Perioperative Pulmonary Atelectasis: Part II. Clinical Implications

Sutureless aortic valve and post-operative atrial fibrillation: Five-year outcomes from a propensity matched cohort study

BACKGROUND

The Perceval Sorin S (perceval valve) is a sutureless bioprosthetic designed for use in a high-risk cohort who may not be suitable for transcatheter aortic valve implantation or a conventional surgical aortic valve replacement (AVR).

AIM

To compare five-year post-operative outcomes in a cohort undergoing isolated AVR with the perceval valve to a contemporary cohort undergoing surgical AVR with a sutured bioprosthesis.

METHODS

This study was a retrospective, cohort study at a single tertiary unit. Between 2017 and 2023, 982 suitable patients were identified. 174 Perceval valve replacements were matched to 174 sutured valve replacements. Cohort characteristics, intra-operative details, and post-operative outcomes were compared between the two groups.

RESULTS

Time under the aortic cross-clamp (P < 0.001), time on the cardiopulmonary bypass (P < 0.001) and total operative time (P < 0.001) were significantly reduced in the Perceval group. Patients in the Perceval valve group were at a lower risk of postoperative pneumonia [odds ratio (OR) = 0.53 (0.29-0.94)] and atrial fibrillation [OR = 0.58 (0.36-0.93)]. After propensity-matching, all-cause mortality did not significantly differ between the two groups in the five-year follow-up period. Larger valve sizes conferred an increased risk of mortality (P = 0.020).

CONCLUSION

Sutureless surgical AVR (SAVR) is a safe and efficient alternative to SAVR with a sutured bioprosthesis, and may confer a reduced risk of post-operative atrial fibrillation. Clinician tendency towards ‘oversizing’ sutureless aortic valves translates into adverse clinical outcomes. Less time on the cardiopulmonary bypass circuit allows for the treatment of otherwise high-risk patients.

A Review of Non-Cardiac Complications of General Anesthesia: The Current State of Knowledge

General anesthesia, despite the constant development of anesthesiology, still carries certain risks. To provide safe anesthesia, it is crucial to properly qualify patients and to react in an appropriate manner when problems occur. It is therefore essential to have knowledge of risk factors, pathophysiology, symptoms, and management patterns regarding complications. This review comprehensively describes respiratory complications such as airway spasm, conditions leading to intraoperative hypoxemia, postoperative pulmonary complications (PPC), and complications of cross airway compromise, from aspects including respiratory complications and mechanical injuries. Moreover, events characteristic of this type of anesthesia, such as anaphylaxis, postoperative nausea and vomiting (PONV), neurological complications, accidental awakening during general anesthesia (AAGA), hypothermia, and malignant hyperthermia (MH), have been included. Each complication is elaborated on in terms of risk groups and factors, symptoms, and prevention and treatment options, taking into account the interrelationship of particular conditions. Although that issue is well reported in the literature, this review, in addition to a comprehensive summary of the most important non-cardiovascular and hemodynamic complications, takes into account the latest findings on methods of prevention, diagnosis, and intraoperative monitoring. The article combines a comprehensive compilation of basic information on the most significant complications, including their diagnosis and methods of intervention, along with consideration of the latest scientific developments and indication of future research directions. This review is based on the most recent articles possible, published between 2006 and 2024.

Analysis of risk factors for hypoxemia in PACU for patients undergoing thoracoscopic lung cancer resection based on logistic regression model

OBJECTIVE

This study aims to identify risk factors of hypoxemia in patients undergoin thoracoscopic lung surgery during their stay in the post-anesthesia care unit (PACU). Hypoxemia was defined as any instance of SpO₂ ≤90% lasting for more than one minute during the PACU stay.

METHODS

We conducted a prospective research involving 398 patients who underwent elective thoracoscopic lung surgery in West China Hospital, Sichuan University, from April to July 2024. Patients were classified into hypoxemia and non-hypoxemia groups based on the presence of hypoxemia in the PACU. We compared clinical data between the two groups to identify factors influencing hypoxemia. Variables with statistical significance (P < 0.05) in univariate analysis were included in logistic regression to identify independent risk factors for hypoxemia.

RESULTS

Among the 398 patients studied, 149 (37.4%) experienced hypoxemia. Univariate analysis indicated significant differences in age, BMI, height, ASA classification, hypertension, diabetes, lung function test with Forced Expiratory Volume at 1 s / Forced Vital Capacity (FEV1/FVC), and awakening time between the groups. Logistic regression revealed that age, BMI, ASA classification, hypertension, diabetes, and awakening time were independent risk factors for hypoxemia during anesthesia recovery, while preoperative SpO2 upon entering operating room (OR = 0.882, 95% CI: 0.783-0.993, P = 0.038) was identified as a protective factor.

CONCLUSION

Age, BMI, ASA classification, and preoperative conditions such as hypertension and diabetes are found to contribute to an increased incidence of hypoxemia in PACU following thoracoscopic lung surgery. Emphasizing preoperative lung function assessments and enhanced monitoring may also facilitate timely interventions, thereby improving post-anesthesia recovery and patient outcomes.

Radiological comparison of atelectasis formation and pleural effusion after open versus thoracoscopic minimally invasive esophagectomy

BACKGROUND

Esophagectomy is associated with pulmonary complications. This study evaluated if thoracoscopic minimally invasive esophagectomy (MIE) mitigates these risks by comparing pulmonary findings on postoperative computed tomography (CT) between open esophagectomy and MIE.

METHOD

Postoperative (day 5) thoracic CT from 40 patients (20 open and 20 MIE) who had undergone esophagectomy with epidural analgesia and right-sided thoracic drainage were reviewed. On an axial view, the areas of atelectasis and pleural effusion were measured at 1 and 5 cm above the right diaphragmatic dome and at the level of the carina. In addition, the total distribution of atelectasis and pleural effusion was estimated on an ordinal scale (0-5), with ≥3 considered clinically important.

RESULTS

The groups were well-matched in terms of age, sex, and smoking status. There were no differences in the areas of atelectasis or pleural effusion for open surgery compared with MIE. The groups did not differ in the proportion of patients with clinically important atelectasis (right: 30% vs. 25%, left: 65% vs. 65%) or pleural effusion (right: 15% vs. 15%, left: 65% vs. 45%). More pleural effusion and atelectasis at the 1-cm level was present on the left side at day 5 in both open and MIE patients.

CONCLUSION

Despite major differences in surgical trauma and ventilation strategies between open and MIE, CT evaluation at day 5 was surprisingly similar. Less right-sided pleural effusion demonstrates the effect of surgical drains. We believe that the defined levels of measurement used in this study, performed at clear anatomical landmarks, can be of value in future studies.

Impact of Preoperative COVID-19 on Postoperative Outcomes in Patients Undergoing Bariatric/Metabolic Surgery: an Updated Analysis of TrinetX Databases

BACKGROUND

The impact of preoperative coronavirus disease (COVID-19) on outcomes after metabolic and bariatric surgery (MBS) remains incompletely understood, as previous studies were conducted early in the pandemic, when viral strains and management differed.

METHODS

Using the TriNetX database, we conducted a retrospective analysis of patients who underwent MBS between June 2022 and December 2024. Patients with COVID-19 within 4 weeks before surgery were propensity-score matched 1:1 with controls without prior COVID-19 based on demographics, obesity-associated medical condition, and laboratory values. The primary outcome was the incidence of postoperative pulmonary complications (i.e., pneumonia or acute respiratory failure), while the secondary outcomes included the incidence of acute kidney injury (AKI), intensive care unit (ICU) admission, other infections (i.e., surgical site infection or urinary tract infection), mortality, and emergency department (ED) visits.

RESULTS

Among 34,652 matched patients, 30-day pulmonary complications showed no significant difference between the COVID-19 and control groups (odds ratio[OR]: 0.898, 95%CI:0.674-1.197, p = 0.4646). However, the COVID-19 group experienced higher rates of AKI (OR:1.407, 95%CI:1.087-1.823, p = 0.0093) and ED visits (OR:1.169, 95%CI:1.082-1.264, p < 0.0001). Other secondary outcomes were similar between the groups. COPD, anemia, and old age were significant risk factors for pulmonary complications. Risk factors for AKI include chronic kidney disease, male sex, anemia, diabetes mellitus, and cardiovascular diseases.

CONCLUSION

Recent preoperative COVID-19 was not associated with increased risk of pulmonary complications following MBS, suggesting surgery need not be delayed for this concern. However, enhanced monitoring of renal complications and post-discharge care may be warranted in patients with identified risk factors.

Early mobilization after anatomical lung resection with thoracotomy

In the past, patients who underwent thoracic surgery were advised to rest, recover, and save energy, avoiding engaging in tiring physical activity. Postoperative rest-centered management of patients following anatomical resection can cause pulmonary and cardiovascular complications. Inability to cough, not deep breathing, dysfunctional diaphragm, pain and lying down cause lung atelectasis, pneumonia, and respiratory failure. Early postoperative mobilization's effects on mental or physical recovery and morbidity rate are unclear. Although advanced technological developments, thoracotomy is still the main incision for thoracic surgery. Lung resection and thoracotomy reduce the quality of patients' daily ambulatory activities. The exercise was shown to have anti-inflammatory effects. Anxiety, fear, and pain activate the same brain regions. Postoperative early mobilization could reduce anxiety and help to reduce the intensity of pain. Many different procedures that stop bed rest, start mobilization, and the walking distance or number of steps during postoperative the first mobilization are applied in the departments of thoracic surgery. How many meters the patient can walk and how many steps he/she needs to take are variable. Protocols to facilitate and enforce early mobilization would be beneficial. Early mobilization can reduce the rate of postoperative complications and length of hospital. Early mobilization as soon as possible within the first 24 h is supported as safe and acceptable in literature.

Efficacy of bronchoalveolar lavage in treating mycoplasma pneumonia and bacterial pneumonia with atelectasis in children

Background

Pulmonary atelectasis (PA) is a severe complication of pneumonia in children. Despite the growing use of fiberoptic bronchoscopy, the effectiveness of bronchoalveolar lavage (BAL) in treating PA caused by various pathogens remains uncertain. This study aims to evaluate the efficacy of BAL in PA associated with different pathogens and to identify factors influencing treatment outcomes.

Methods

We conducted a retrospective analysis on 185 children with PA between 2017-2021. Clinical data were collected and compared between different groups using a propensity score-matching analysis.

Results

A total of 185 patients were included in the study, divided into two groups based on whether BAL was performed (BAL group, n=146; non-BAL group, n=39). The patients in the BAL group had a longer fever duration, a higher proportion of neutrophils, elevated lactate dehydrogenase (LDH) levels, and a longer duration of antibiotic use prior to admission (all P<0.05). After applying propensity score matching (PSM), 35 cases were enrolled in each group. We further stratified the patients based on the pathogens identified. Furthermore, we found that patients in the Mycoplasma pneumoniae pneumonia (MPP) subgroup had shorter time of C-reactive protein (CRP) recovery and higher incidence of lung recruitment after BAL (all P<0.05), while these results were not observed in the bacterial pneumonia subgroup (P>0.05).

Conclusions

BAL could increase the incidence of lung recruitment and shorten the CRP recovery time in MPP patients with PA, but it could not make any improvement in PA patients caused by the bacterium.

Perioperative oxygen administration for adults undergoing major noncardiac surgery: a narrative review

Perioperative oxygen administration, a topic under continuous research and debate in anesthesiology, strives to optimize tissue oxygenation while minimizing the risks associated with hyperoxia and hypoxia. This review provides a thorough overview of the current evidence on the application of perioperative oxygen in adult patients undergoing major noncardiac surgery. The review begins by describing the physiological reasoning for supplemental oxygen during the perioperative period and its potential benefits while also focusing on potential hyperoxia risks. This review critically appraises the existing literature on perioperative oxygen administration, encompassing recent clinical trials and meta-analyses, to elucidate its effect on postoperative results. Future research should concentrate on illuminating the optimal oxygen administration strategies to improve patient outcomes and fine-tune perioperative care protocols for adults undergoing major noncardiac surgery. By compiling and analyzing available evidence, this review aims to provide clinicians and researchers with comprehensive knowledge on the role of perioperative oxygen administration in major noncardiac surgery, ultimately guiding clinical practice and future research endeavors.

Comparison of remimazolam-based and propofol-based general anaesthesia on postoperative quality of recovery in patients undergoing laparoscopic sleeve gastrectomy: protocol for a prospective, randomised, parallel-group, non-inferiority trial

INTRODUCTION

Remimazolam is a novel short-acting benzodiazepine that exhibits sedative and hypnotic properties without compromising respiratory function and while maintaining haemodynamic stability. Its safety and efficacy have been demonstrated to be non-inferior to those of propofol in the context of general anaesthesia. Nevertheless, the non-inferiority in terms of postoperative recovery quality in obese patients has not been established. Thus, we conducted a prospective, randomised, parallel-group, non-inferiority study to compare remimazolam-based general anaesthesia with propofol-based general anaesthesia on the postoperative quality of recovery (QoR) in patients undergoing laparoscopic sleeve gastrectomy.

METHODS AND ANALYSIS

All participants meeting the included criteria will be enrolled after signing an informed consent form. Patients will be randomly allocated to either the propofol group (n=63; induction and maintenance with propofol) or the remimazolam group (n=63; induction and maintenance with remimazolam). The primary endpoint of the study is the 15-item QoR Scale assessed at 24 hours postoperatively. Secondary endpoints include the doses of anaesthetic required for loss of consciousness (LOC), the time to LOC, the time to recovery of consciousness, the total amount of anaesthetic administered during the surgery and the incidence of hypotension and bradycardia. Additionally, postoperative profiles of pain, nausea and vomiting, delirium, intraoperative awareness, adverse events and patient satisfaction will be collected. Statistical analyses will be performed using IBM SPSS Statistics V.26.0 and GraphPad Prism V.5.01. Statistical significance is set at two-sided p values<0.05.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the ethics committees of Beijing Chaoyang Hospital, Capital Medical University (No. 2023ke715-1). The findings will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2400083700.

Perioperative lung expansion and pulmonary outcomes after open abdominal surgery versus usual care in the USA (PRIME-AIR): a multicentre, randomised, controlled, phase 3 trial

BACKGROUND

Postoperative pulmonary complications (PPCs) are a leading cause of morbidity, death, and increased use of health-care resources. We aimed to determine whether a perioperative lung expansion bundle including individualised intraoperative management reduces PPC severity in patients undergoing major open abdominal surgery compared with usual care.

METHODS

In this multicentre, randomised controlled phase 3 trial (PRIME-AIR), we enrolled adult patients (age ≥18 years) scheduled for an elective open abdominal surgery that would last at least 2 h, who were at intermediate or high risk for PPCs on the basis of their Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score (a score of ≥26), and who had a BMI below 35 kg/m2 at 17 academic hospitals across ten states in the USA. Participants were randomly assigned (1:1), using permuted block randomisation (a mixture of blocks sizes of 2 and 4; in a 1:2 ratio), stratified by centre, to either usual care or a lung expansion bundle. The bundle comprised preoperative education on PPCs, intraoperative protective ventilation with individualised positive end-expiratory pressure (PEEP) to maximise respiratory system compliance, intraoperative neuromuscular blockade administration and reversal based on patient's weight and neuromuscular transmission monitoring, and postoperative supervised incentive spirometry and mobilisation encouragement. Anaesthesiologists at each site were also randomly assigned to either the intervention bundle group or usual care group, and at each site, at least one unmasked and one masked investigator was designated for each participant. Assessors were masked to treatment assignment. The primary outcome was the highest severity (grade 0-4) of a composite of PPCs by postoperative day 7, including hypoxaemia, respiratory symptoms, atelectasis, bronchospasm, respiratory infection, hypercapnia, pneumonia, pleural effusion, pneumothorax, and ventilatory dependence. The primary endpoint and safety were assessed in the modified intention-to-treat (mITT) population (ie, all participants randomly assigned to treatment who received surgery, and did not withdraw consent or verbal agreement, and excluded those found to be ineligible after randomisation, or for whom consent was not obtained for other reasons). This study is registered with ClinicalTrials.gov, NCT04108130, and is now complete.

FINDINGS

Between Jan 24, 2020, and April 5, 2023, we screened 1462 patients, of whom 794 were enrolled and randomly assigned to treatment. The mITT population included 751 participants, of whom 379 (50%) were in the intervention bundle group and 372 (50%) were in the usual care group. Mean age was 61·8 years (SD 12·8); 360 (48%) of 751 patients were female and 391 (52%) were male; 572 (76%) were White, 44 (6%) were Black, 35 (5%) were Asian, and ten (1%) were other races or more than one race. Adherence to bundle components was high (72-98%). Patients in the intervention bundle group received higher mean PEEP (7·5 cmH2O [SD 2·5] vs 5·6 cmH2O [1·4]) and more frequent per-protocol dosing of neuromuscular blockade (334 [88%] of 379 vs 214 [58%] of 372) and reversal (322 [86%] of 375 who received reversal medication vs 250 [70%] of 358) than did those in the usual care group. By postoperative day 7, the most common PPC severity was grade 2 (211 [56%] of 379 in intervention bundle group vs 225 [60%] of 372 in the usual care group). Mean PPC severity was similar in both groups (1·60 [SD 0·94] vs 1·53 [0·93]; mean difference 0·07 [95% CI -0·03 to 0·18]; p=0·19). Occurrence of serious adverse events was similar in both groups. At 7 days postoperatively, one (<1%) patient in the intervention bundle group and two (1%) in the usual care group had died; at 30 days, cumulatively, one (<1%) patient and four (1%) patients had died; and at 90 days, cumulatively, six (2%) patients and five (1%) patients had died, respectively. Adverse events occurred in 71 (19%) of 379 patients in the intervention bundle group and 54 (14%) of 372 in the usual care group, and 35 (9%) patients in each group had serious adverse events.

INTERPRETATION

In patients with a BMI of less than 35 kg/m2 who are at moderate-to-high risk of PPCs and undergoing prolonged major open abdominal surgery, a perioperative lung expansion bundle did not reduce PPC severity compared with usual care provided at US academic hospitals.

FUNDING

US National Institutes for Health National Heart, Lung, and Blood Institute.

Airway clearance technique therapy for atelectasis induced by scoliosis surgery: a case report

The patient, a 55-year-old female presenting with spinal deformity and exertional dyspnea, was referred to the hospital. Radiographic evaluation of her spine revealed an "S"-shaped scoliosis with a Cobb angle measuring 68°, indicative of severe scoliosis. Despite receiving medication for expectoration, postoperative symptoms including chest tightness, breathlessness, and ineffective coughing persisted and progressively worsened. Subsequent chest CT scans demonstrated extensive atelectasis, and pharmacological interventions proved to be ineffective. Considering the patient's clinical condition, we implemented airway clearance technique (ACT) along with prone ventilation to optimize cough effectiveness and mitigate atelectasis formation. The airway clearance techniques (ACT) employed include nebulization, continuous positive expiratory pressure (CPEP), and continuous high frequency oscillation (CHFO). Chest CT imaging confirmed that ACT substantially alleviated the patient's pulmonary atelectasis. Moreover, blood gas analysis indicated significant improvements in both the PaO2/FiO2 ratio and base excess of whole blood. Follow-up evaluation 1 year post-discharge revealed a favorable prognosis for the patient. We anticipate that our experience utilizing these novel therapeutic modalities will provide valuable insights for clinicians managing similar complications.

Mapping Trends and Hotspots Regarding the Use of Lung Ultrasound in the Field of Anesthesiology: A Bibliometric Analysis of Global Research

Purpose

Lung ultrasound (LUS) is increasingly utilized in the field of anesthesiology due to its focused, quick application and the advantage of not exposing patients to ionizing radiation. This study aims to analyze the status and trends in this area from a macroscopic perspective.

Methods

A bibliometric analysis was conducted using the Web of Science (WoS) Core Collection. The analysis and visualization were performed using WoS, Excel, VOSviewer, and CiteSpace. Parameters such as publications, countries, institutions, journals, and keywords were analyzed.

Results

A total of 133 articles published over the last 10 years were analyzed to clarify the current status and future trends on the use of LUS in anesthesiology. The number of publications increased markedly from May 1, 2014, to April 30, 2024. China is the highest productive country, while the USA had the highest number of citations. In the institution, Seoul National University in South Korea published the most articles and had the highest number of citations. Kim Jin-Tae emerged as the most prolific and influential author. BMC Anesthesiology and the Journal of Cardiothoracic and Vascular Anesthesia were identified as the most popular journals in the field. Keywords such as "atelectasis", "mechanical ventilation", and "pulmonary complications" were closely related to the use of LUS in anesthesiology.

Conclusion

This study provides a comprehensive analysis of research on the use of LUS in anesthesiology, highlighting the growing interest in LUS and its relevance to pulmonary complications.

High Positive End-expiratory Pressure (PEEP) with Recruitment Maneuvers versus Low PEEP during General Anesthesia for Surgery: A Bayesian Individual Patient Data Meta-analysis of Three Randomized Clinical Trials

BACKGROUND

The influence of high positive end-expiratory pressure (PEEP) with recruitment maneuvers on the occurrence of postoperative pulmonary complications after surgery is still not definitively established. Bayesian analysis can help to gain further insights from the available data and provide a probabilistic framework that is easier to interpret. The objective was to estimate the posterior probability that the use of high PEEP with recruitment maneuvers is associated with reduced postoperative pulmonary complications in patients with intermediate-to-high risk under neutral, pessimistic, and optimistic expectations regarding the treatment effect.

METHODS

Multilevel Bayesian logistic regression analysis was performed on individual patient data from three randomized clinical trials carried out on surgical patients at intermediate to high risk for postoperative pulmonary complications. The main outcome was the occurrence of postoperative pulmonary complications in the early postoperative period. This study examined the effect of high PEEP with recruitment maneuvers versus low PEEP ventilation. Priors were chosen to reflect neutral, pessimistic, and optimistic expectations of the treatment effect.

RESULTS

Using a neutral, pessimistic, or optimistic prior, the posterior mean odds ratio for high PEEP with recruitment maneuvers compared to low PEEP was 0.85 (95% credible interval, 0.71 to 1.02), 0.87 (0.72 to 1.04), and 0.86 (0.71 to 1.02), respectively. Regardless of prior beliefs, the posterior probability of experiencing a beneficial effect exceeded 90%. Subgroup analysis indicated a more pronounced effect in patients who underwent laparoscopy (odds ratio, 0.67 [0.50 to 0.87]) and those at high risk for postoperative pulmonary complications (odds ratio, 0.80 [0.53 to 1.13]). Sensitivity analysis, considering severe postoperative pulmonary complications only or applying a different heterogeneity prior, yielded consistent results.

CONCLUSIONS

High PEEP with recruitment maneuvers demonstrated a moderate reduction in the probability of postoperative pulmonary complication occurrence, with a high posterior probability of benefit observed consistently across various prior beliefs, particularly among patients who underwent laparoscopy.

EDITOR’S PERSPECTIVE

The effect of lung-recruitment maneuver on postoperative shoulder pain in patients undergoing laparoscopic cholecystectomy: a randomized controlled trial

PURPOSE

Lung-recruitment maneuvers (LRM) have been shown to reduce postoperative pain after laparoscopic surgery. This study aimed to investigate the association of LRM with the incidence of shoulder pain after laparoscopic cholecystectomy.

METHODS

A randomized controlled study was conducted with 110 patients undergoing elective laparoscopic cholecystectomy from July 2022 to March 2023. Participants were randomized to receive either routine exsufflation or LRM at pneumoperitoneum release. The postoperative shoulder pain and abdominal pain were assessed at 1, 4, 6, 12, and 24 h after surgery using a numeric rating scale. Analgesic consumption and postoperative nausea or vomiting (PONV) were evaluated during the first 24 h after surgery.

RESULTS

The incidence of shoulder pain during the first 24 h after surgery was significantly lower in the LRM group compared to the control group (26.9 vs. 59.3%; P = 0.001). The median [interquartile range] score of worst shoulder pain was significantly lower compared to the control group (3 [2-3] vs 4 [3-5.5]; P = 0.003). Participants in the LRM group showed reduced abdominal pain at rest at 4 and 24 h after surgery, and experienced significantly lower intensities of abdominal pain during mobilization at all time points over 24 h after surgery. There were no significant differences in opioid consumption or the incidence of PONV between the groups.

CONCLUSIONS

LRM reduces both the incidence and intensity of shoulder pain during 24 h after laparoscopic cholecystectomy. Additionally, LRM was associated with reduced intensity of abdominal pain during mobilization over the study period.

Effect of ultrasound-guided individualized positive end-expiratory pressure on the severity of postoperative atelectasis in elderly patients: a randomized controlled study

Postoperative pulmonary complications (PPCs) are common in patients undergoing general anesthesia, with atelectasis being a key contributor that increases postoperative mortality and prolongs hospitalization. Our research hypothesis is that ultrasound-guided individualized PEEP titration can reduce postoperative atelectasis. This single-center randomized controlled trial recruited elderly patients for laparoscopic surgery. Patients were randomly assigned to two group: the study group (individualized PEEP groups, PEEP Ind group) and the control group (Fixed PEEP group, PEEP 5 group). All patients in these two groups received volume-controlled ventilation during general anesthesia. Patients in the study group were given ultrasound-guided PEEP, while those in the control group were given a fixed 5 cmH2O PEEP. Bedside ultrasound assessed lung ventilation. The primary outcome was the severity of atelectasis within seven days post-surgery. Eighty-nine patients scheduled for elective laparoscopic radical surgery for colorectal cancer were enrolled in our study. Lung ultrasound scores (LUSs) in the study group during postoperative seven days was significantly decreased compared with that in the control group (P < 0.05). The severity of postoperative atelectasis in the study group was significantly improved. The incidence of PPCs during postoperative 7 days in the study group was significantly less than that in the control group (48.6% vs. 77.8%; RR = 0.625; CI = 0.430-0.909; P = 0.01). In elderly patients undergoing laparoscopic radical resection, lung ultrasound-guided individualized PEEP can alleviate the severity of postoperative atelectasis.Clinical trial number and registry URL: No. ChiCTR2200062979 ( https://www.chictr.org.cn ).

The Protective Role of the Ratio of Arterial Partial Pressure of Oxygen and Fraction of Inspired Oxygen after Re-Supination in the Survival of Patients with Severe COVID-19 Pneumonia

Background

The role of the ratio between the arterial partial pressure of oxygen and the inspired fraction of oxygen (PaO2/FiO2 ratio) during the change in position is not fully established.

Methods

This retrospective, single-center cohort study included 98 patients with severe COVID-19 pneumonia.

Objective

This study aimed to evaluate the predictive value of the PaO2/FiO2 ratio for survival in patients with severe COVID-19 pneumonia between changing from supine to prone positions and vice versa. The PaO2/FiO2 ratio was measured preproning (T0), 30 min to 1 hour (T1), and 48 h after prone positioning (T2), and 30 min to 1 h after re-supination (T3).

Results

The PaO2/FiO2 ratio at T2 and T3 was higher in the survivors than in the non-survivors (T2= 251.5 vs. 208.5, p= 0.032; T3= 182 vs. 108.5, p<0.001). The PaO2/FiO2 ratio at T3 was an independent protective factor (Hazard Ratio (HR)= 0.993; 95% Confidence Interval (CI)= 0.989-0.998; p= 0.006) for survival. A threshold of ≤129 for the PaO2/FiO2 ratio at T3 predicted non-survival with a sensitivity and specificity of 67.86 and 80.95, respectively (Area Under the Curve (AUC)= 0.782; 95% CI 0.687-0.859).

Conclusion

The PaO2/FiO2 ratio is a significant protective factor of survival in severe COVID-19 pneumonia within 30 min-1 hour after returning to the supine position (re-supination).

Pulmonary Atelectasis After Sedation With Propofol vs Propofol-Ketamine for Magnetic Resonance Imaging in Children: A Randomized Clinical Trial

Importance

Little is known about the impact of different anesthetic agents used for routine magnetic resonance imaging (MRI) sedation on pulmonary function in children.

Objective

To compare the incidence of pulmonary atelectasis after MRI sedation with propofol vs propofol-ketamine.

Design, Setting, and Participants

This double-masked randomized clinical trial screened 117 consecutive pediatric patients aged 3 to 12 years with American Society of Anesthesiologists physical status I to II undergoing elective MRI under deep sedation from November 2, 2022, to April 28, 2023, at a tertiary referral center. Four patients met the exclusion criteria, and 5 patients refused to participate. The participants and outcome assessors were masked to the group allocation.

Interventions

During the MRI, the propofol group received 0.2 mL/kg of 1% propofol and 2 mL of 0.9% saline followed by a continuous infusion of propofol (200 μg/kg/min) and 0.9% saline (0.04 mL/kg/min). The propofol-ketamine group received 0.2 mL/kg of 0.5% propofol and 1 mg/kg of ketamine followed by a continuous infusion of propofol (100 μg/kg/min) and ketamine (20 μg/kg/min).

Main Outcome and Measure

The incidence of atelectasis assessed by lung ultrasonography examination.

Results

A total of 107 children (median [IQR] age, 5 [4-6] years; 62 male [57.9%]), with 54 in the propofol group and 53 in the propofol-ketamine group, were analyzed in this study. Notably, 48 (88.9%) and 31 (58.5%) patients had atelectasis in the propofol and propofol-ketamine groups, respectively (relative risk, 0.7; 95% CI, 0.5-0.8; P < .001). The incidence of desaturation and interruption of the MRI due to airway intervention or spontaneous movement did not significantly differ between the groups. The propofol-ketamine group showed a faster emergence time than the propofol group (15 [9-23] vs 25 [22-27] minutes in the propofol-ketamine vs propofol group; median difference in time, 9.0 minutes; 95% CI, 6.0-12.0 minutes; P < .001). No patient was withdrawn from the trial due to adverse effects.

Conclusions and Relevance

In this randomized clinical trial, the propofol-ketamine combination reduced sedation-induced atelectasis while allowing for faster emergence compared with propofol alone.

Trial Registration

cris.nih.go.kr Identifier: KCT0007699.

Individualized positive end-expiratory pressure in laparoscopic surgery: a randomized controlled trial

BACKGROUND

The reduction in functional residual capacity (FRC) is a significant pathological factor in the development of postoperative pulmonary complications. Appropriate positive end-expiratory pressure (PEEP) is critical to preserve FRC during mechanical ventilation. Our previous study suggests that using driving pressure-guided PEEP can reduce postoperative pulmonary complications. In this study, we hypothesize that individualized PEEP can increase immediate postoperative FRC and improve lung ventilation.

METHODS

This single-centered, randomized controlled trial included a total of 91 patients scheduled for laparoscopic surgery for colorectal carcinoma. Patients were randomly assigned to receive individualized PEEP guided by minimum driving pressure or a fixed PEEP of six cmH2O. The primary outcome was postoperative FRC. Secondary outcomes included the incidence of postoperative pulmonary complications, postoperative Oxygenation Index, alveolar-arterial oxygen tension difference (PA-aO2), intrapulmonary shunt (QS/QT), and Respiratory Index, as well as lung ventilation measured by electrical impedance tomography.

RESULTS

The median value of PEEP in the individualized group was 14 cmH2O, with an interquartile range of 12-14 cmH2O. The postoperative FRC was significantly higher in the individualized PEEP group than that in the PEEP six cmH2O group (32.8 [12.8] vs. 25.0 [12.6] mL/kg, P=0.004). Patients receiving driving pressure-guided PEEP also had significantly higher Oxygenation Index, better ventilation distribution, and lower PA-aO2, QS/QT, and Respiratory Index.

CONCLUSIONS

Driving pressure-guided PEEP can preserve postoperative FRC and provide better ventilation and oxygenation for patients undergoing laparoscopic colorectal surgery.

The effects of laryngeal mask versus endotracheal tube on atelectasis after general anesthesia induction assessed by lung ultrasound: A randomized controlled trial

STUDY OBJECTIVE

This study aims to evaluate the impact of Supreme™ laryngeal masks versus endotracheal tubes on atelectasis during general anesthesia using lung ultrasound (LUS), and provide evidence for respiratory management.

DESIGN

A single-center, double-blind, randomized controlled trial was conducted.

SETTING

The study was conducted in both the operating room and the post-anesthesia care unit, with follow-up assessments performed in the ward.

PATIENTS

Enrollment included 180 cases undergoing non-laparoscopic surgeries in gynecology, urology, and orthopedic limb surgeries.

INTERVENTIONS

Patients were randomly assigned 1:1 to the endotracheal intubation or laryngeal mask group.

MEASUREMENTS

LUS scores were recorded across 12 lung regions at baseline, 15 min after airway establishment, at the end of surgery, and 30 min following airway removal. Outcome measures encompassed the oxygenation index, dynamic lung compliance, incidence of postoperative pulmonary complications, throat pain, and other postoperative complications assessed at 24 and 48 h postoperatively. The primary outcome focused on the LUS score in all 12 lung regions at 15 min after airway establishment.

MAIN RESULTS

Intention-to-treat analysis of 177 subjects revealed endotracheal intubation led to significantly higher LUS scores at 15 min {P < 0.001, mean difference 4.15 ± 0.60, 95% CI [2.97, 5.33]}, end of surgery (P < 0.001, mean difference 3.37 ± 0.68, 95% CI [2.02, 4.72]), and 30 min post-removal (P < 0.001, mean difference 2.63 ± 0.48, 95% CI [1.68, 3.58]). No major complications occurred in the two groups.

CONCLUSIONS

Compared to endotracheal intubation, laryngeal masks effectively reduce atelectasis formation and progression in gynecological, urological non-laparoscopic, and orthopedic limb surgeries. However, caution is warranted when generalizing these findings to surgeries with a higher risk of laryngeal mask leakage or obese patients. Additionally, the efficacy of laryngeal masks in reducing postoperative atelectasis remains uncertain when comprehensive monitoring of muscle relaxation and reversal therapy is employed.

Rescue analgesia with a transversus abdominis plane block alleviates moderate-to-severe pain and improves oxygenation after abdominal surgery: a randomized controlled trial

Background

Abdominal surgery is a common surgical procedure that is frequently associated with substantial postoperative pain. However, rescue analgesia using opioids is associated with several adverse effects. The transversus abdominis plane block (TAPB) has been demonstrated to be effective as part of multimodal analgesia. This study aims to evaluate the effects of rescue analgesia using the TAPB following abdominal surgery.

Methods

Ninety patients undergoing abdominal surgery and reporting a numeric rating scale (NRS) score of cough pain ≥4 on the first postoperative day were randomized to receive either sufentanil or TAPB for rescue analgesia. Pain scores and arterial oxygen pressure (PaO2) were evaluated before and after the administration of rescue analgesia. Sleep quality and gastrointestinal function were assessed postoperatively. The primary outcome was the degree of pain relief on coughing 30 min after the administration of rescue analgesia.

Results

Patients of both groups reported a significantly reduced NRS score on coughing 30 min after receiving rescue analgesia (P paired < 0.001 for both groups). Notably, the degree of pain relief was significantly higher in the TAPB group than in the sufentanil group [median (interquartile range), -3 (-4 to -2) vs. -2 (-2 to -1), median difference = -1; 95% confidence interval, -2 to -1; P < 0.001]. Moreover, patients in the TAPB group experienced less pain than those in the sufentanil group during the following 24 h. When evaluated, PaO2 increased significantly after rescue analgesia was administered in the TAPB group (P paired < 0.001); however, there were no significant intragroup differences in the sufentanil group (P paired = 0.129). Patients receiving the TAPB experienced better quality of sleep than those receiving sufentanil (P = 0.008), while no statistical differences in gastrointestinal function were observed between the two groups.

Conclusion

Rescue analgesia with the TAPB on the first postoperative day alleviated pain, enhanced oxygenation, and improved sleep quality in patients undergoing abdominal surgery; however, its effect on gastrointestinal function requires further research.

Clinical Trial Registration

This study was registered in the Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj=170983, ChiCTR2200060285) on 26 May 2022: Patients were recruited during the period between 30 May 2022 and 14 February 2023, and a follow-up of the last enrolled patient was completed on 16 March 2023.

A comparison of the effects of lung protective ventilation and conventional ventilation on the occurrence of atelectasis during laparoscopic surgery in young infants: a randomized controlled trial

Objective

This study utilized lung ultrasound to investigate whether lung protective ventilation reduces pulmonary atelectasis and improves intraoperative oxygenation in infants undergoing laparoscopic surgery.

Methods

Eighty young infants (aged 1-6 months) who received general anesthesia for more than 2 h during laparoscopic surgery were randomized into the lung protective ventilation group (LPV group) and the conventional ventilation group (control group). The LPV group received mechanical ventilation starting at 6 mL/kg tidal volume, 5 cmH2O PEEP, 60% inspired oxygen fraction, and half-hourly alveolar recruitment maneuvers. Control group ventilation began with 8-10 mL/kg tidal volume, 0 cmH2O PEEP, and 60% inspired oxygen fraction. Lung ultrasound was conducted five times-T1 (5 min post-intubation), T2 (5 min post-pneumoperitoneum), T3 (at the end of surgery), T4 (post-extubation), and T5 (prior to discharge from the PACU)-for each infant. Simultaneous arterial blood gas analysis was performed at T1, T2, T3, and T4.

Results

Statistically significant differences were observed in pulmonary atelectasis incidence, lung ultrasound scores, and the PaO2, PaCO2, PaO2/FiO2 ratios at T2, T3, and T4. However, at T5, no statistically significant differences were noted in terms of lung ultrasound scores (4.30 ± 1.87 vs. 5.00 ± 2.43, 95% CI: -1.67 to 0.27, p = 0.153) or the incidence of pulmonary atelectasis (32.5% vs. 47.5%, p = 0.171).

Conclusion

In infants aged 1-6 months, lung protective ventilation during laparoscopy under general anesthesia significantly reduced the incidence of pulmonary atelectasis and enhanced intraoperative oxygenation and dynamic lung compliance compared to conventional ventilation. However, these benefits did not persist; no differences were observed in lung ultrasound scores or the incidence of pulmonary atelectasis at PACU discharge.

Clinical trial registration

http://www.chictr.org.cn/, identifier: ChiCTR2200058653.

Lung ultrasound assessment of atelectasis following different anesthesia induction techniques in pediatric patients: a propensity score-matched, observational study

INTRODUCTION

Atelectasis is a well-documented complication in pediatric patients undergoing general anesthesia. Its incidence varies significantly based on surgical procedures and anesthesia techniques. Inhalation induction, commonly used to avoid the discomfort of venipuncture, is suspected to cause higher rates of respiratory complications, including atelectasis, compared to intravenous induction. This study aimed to evaluate the impact of inhalation versus intravenous anesthesia induction on atelectasis formation in pediatric patients, as assessed by lung ultrasound (LUS).

METHODS

This propensity score-matched observational study was conducted at a tertiary pediatric hospital in Milan, Italy. Inclusion criteria were children ≤ 18 years undergoing elective surgery with general anesthesia. Patients were divided into inhalation and intravenous induction groups. LUS was performed before and after anesthesia induction to assess lung aeration. The primary endpoint was the global LUS score post-induction, with secondary endpoints including the incidence and distribution of atelectasis.

RESULTS

Of the 326 patients included, 65% underwent inhalation induction and 35% intravenous induction. The global LUS score was significantly higher in the inhalation group (12.0 vs. 4.0, p < 0.001). After propensity score matching (for age, presence of upper respiratory tract infection, duration of induction, and PEEP levels at induction), average treatment effect (ATE) of mask induction was 5.89 (95% CI, 3.21-8.58; p < 0.001) point on LUS global score and a coefficient of 0.35 (OR 1.41) for atelectasis.

DISCUSSION

Inhalation induction is associated with a higher incidence of atelectasis in pediatric patients also when we adjusted for clinically relevant covariates.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT06069414.

Strategy of Severe Pneumonia and Management of Related Complications After Autogenous Cartilage Microtia Reconstruction

Since the pioneering use of autologous costal cartilage for microtia reconstruction, significant progress has been made in treating microtia, effectively improving patients' quality of life and reducing their psychological burden. Cartilage auricle reconstruction is the primary treatment, but many postoperative complications can occur. Common postoperative complications include infection and hematoma at the recipient site, pleural tears at the donor site, and thoracic scoliosis. Among these, severe postoperative pneumonia is a rare but potentially fatal complication. This study presents a case of severe pneumonia after auricular reconstruction with autologous cartilage. It details the complications associated with autologous cartilage microtia reconstruction, especially pulmonary complications, and suggests a possible relationship between pulmonary complications and auricular reconstruction using cartilage.

A Comparison of the Effects of Different Positive End-Expiratory Pressure Levels on Respiratory Parameters During Prone Positioning Under General Anaesthesia: A Randomized Controlled Trial

Background and objective In general anesthesia, for certain surgical procedures in the prone position, patients often face increased airway pressures, reduced pulmonary and thoracic compliance, and restricted chest expansion, all of which can affect venous return and cardiac output, impacting overall hemodynamic stability. Positive end-expiratory pressure (PEEP) is used to address these issues by improving lung recruitment and ventilation while reducing stress on lung units. However, different PEEP levels also present risks such as increased parenchymal strain, higher pulmonary vascular resistance, and impaired venous return.  Proper positioning and frequent monitoring are key to ensuring adequate oxygenation and minimizing complications arising from prolonged periods in the prone position. This study aimed to evaluate the effects of different PEEP levels (0 cmH2O, 5 cmH2O, and 10 cmH2O) in the prone position to determine the optimal setting for balancing improved oxygenation and lung recruitment against potential adverse effects. The goal is to refine individualized PEEP strategies beyond what is typically outlined in standard PEEP tables. We endeavored to examine the impact of different PEEP levels during pressure-controlled ventilation (PCV) on arterial oxygenation, respiratory parameters, and intraoperative blood loss in patients undergoing spine surgery in a prone position under general anesthesia. Methodology This randomized, single-blinded, controlled study enrolled 90 patients scheduled for elective spine fixation surgeries. Patients were randomized into three groups: Group A (PEEP 0), Group B (PEEP 5), and Group C (PEEP 10). Standardized anesthesia protocols were administered to all groups, with ventilation set to pressure-controlled mode at desired levels. PEEP levels were adjusted according to group allocation. Arterial blood gases were measured before induction, 30 minutes after prone positioning, and 30 minutes post-extubation. Arterial line insertion was performed, and dynamic compliance, mean arterial pressure (MAP), heart rate (HR), and intraoperative blood loss were recorded at regular intervals. Data were analyzed using SPSS Statistics version 21 (IBM Corp., Armonk, NY). Results Arterial oxygenation was significantly higher in Groups B (PEEP 5) and C (PEEP 10) compared to Group A (PEEP 0) at both 30 minutes post-intubation and post-extubation. Specifically, at 30 minutes post-intubation, arterial oxygenation was 142.26 ±24.7 in Group B and 154.9 ±29.88 in Group C, compared to 128.18 ±13.3 in Group A (p=0.002). Similarly, post-extubation arterial oxygenation levels were 105.1 ±8.28 for Group B and 115.46 ±15.2 for Group C, while Group A had levels of 97.07 ±9.90 (p<0.001). MAP decreased significantly in Groups B and C compared to Group A. Dynamic compliance was also improved in Groups B and C. Furthermore, intraoperative blood loss was notably lower in Group C (329.66 ±93.93) and Group B (421.16 ±104.52) compared to Group A (466.66 ±153.76), and these differences were statistically significant. Conclusions Higher levels of PEEP (10 and 5 cmH2O) during prone positioning in spine surgery improve arterial oxygenation, dynamic compliance, and hemodynamic stability while reducing intraoperative blood loss. These findings emphasize the importance of optimizing ventilatory support to enhance patient outcomes during prone-position surgeries.

Effect on post-operative pulmonary complications frequency of high flow nasal oxygen versus standard oxygen therapy in patients undergoing esophagectomy for cancer: study protocol for a randomized controlled trial-OSSIGENA study

Background

Postoperative pulmonary complications (PPCs) remain a challenge after esophagectomy. Despite improvement in surgical and anesthesiological management, PPCs are reported in as many as 40% of patients. The main aim of this study is to investigate whether early application of high-flow nasal cannula (HFNC) after extubation will provide benefit in terms of reduced PPC frequency compared to standard oxygen therapy.

Methods

Patients aged 18-85 years undergoing esophagectomy for cancer treatment with radical intent, excluding those with American Society of Anesthesiologists (ASA) score >3 and severe systemic comorbidity (cardiac, pulmonary, renal or hepatic disease) will be randomized at the end of surgery to receive HFNC or standard oxygen therapy (Venturi mask or nasal goggles) after early extubation (within 12 hours after the end of surgery) for 48 hours. The main postoperative goals are to obtain SpO2 ≥94% and adequate pain control. Oxygen therapy after 48 hours will be stopped unless the physician deems it necessary. In case of respiratory clinical worsening, patients will be supported with the most appropriate tool (noninvasive ventilation or invasive mechanical ventilation). Pulmonary [pneumonia, pleural effusion, pneumothorax, atelectasis, acute respiratory distress syndrome (ARDS), tracheo-bronchial injury, air leak, reintubation, and/or respiratory failure] complications will be recorded as main outcome. Secondary outcomes, including cardiovascular, surgical, renal and infective complications will also be recorded. The primary analysis will be carried out on 320 patients (160 per group) and performed on an intention-to-treat (ITT) basis, including all participants randomized into the treatment groups, regardless of protocol adherence. The primary outcome, the PPC rate, will be compared between the two treatment groups using a chi-square test for categorical data, or Fisher's exact test will be used if the assumptions for the chi-square test are not met.

Discussion

Recent evidence demonstrated that early application of HFNC improved the respiratory rate oxygenation index (ROX index) after esophagectomy but did not reduce PPCs. This randomized controlled multicenter trial aims to assess the potential effect of the application of HFNC versus standard oxygen over PPCs in patients undergoing esophagectomy.

Trial Registration

This study is registered at clinicaltrial.gov NCT05718284, dated 30 January 2023.

Hypercapnia during transcatheter aortic valve replacement under monitored anaesthesia care: a retrospective cohort study

BACKGROUND

Acute intraoperative hypercapnia and respiratory acidosis, which can occur during monitored anaesthesia care (MAC), pose significant cardiopulmonary risks for patients with aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). The goal of the present study is to assess the incidence, risk factors and impact of intraoperative hypercapnia during MAC for patients undergoing transfemoral TAVR.

METHODS

Data was collected retrospectively from the electronic medical record of 201 consecutive patients with available intraoperative arterial blood gas (ABG) data who underwent percutaneous transfemoral TAVR with MAC using propofol and dexmedetomidine. ABGs (pH, arterial partial pressure of carbon dioxide (PaCO2) and arterial partial pressure of oxygen) were performed at the start of each case (baseline), immediately prior to valve deployment (ValveDepl), and on arrival to the postanaesthesia care unit. Data was analysed using Fisher's exact test, unpaired Student's t-test, Wilcoxon rank sum or univariate linear regression as appropriate based on PaCO2 and pH during ValveDepl (PaCO2-ValveDepl, pH-ValveDepl) and change in PaCO2 and pH from baseline to ValveDepl (PaCO2-%increase, pH-%decrease) to determine their association with preoperative demographic data, intraoperative anaesthetic and vasoactive medications and postoperative outcomes.

RESULTS

PaCO2 increased by a mean of 28.4% and was higher than baseline in 91% of patients. Younger age, male sex, increased weight and increased propofol dose contributed to higher PaCO2-ValveDepl and greater PaCO2-%increase. Patients with PaCO2-ValveDepl>60 mm Hg, pH≤7.2 and greater pH-%decrease were more likely to receive vasoactive medications, but perioperative PaCO2 and pH were not associated with adverse postoperative outcomes.

CONCLUSIONS

Transient significant hypercapnia commonly occurs during transfemoral TAVR with deep sedation using propofol and dexmedetomidine. Although the incidence of postoperative outcomes does not appear to be affected by hypercapnia, the need for vasopressors and inotropes is increased. If deep sedation is required for TAVR, hypercapnia and the need for haemodynamic and ventilatory support should be anticipated.

Preoperative Atelectasis in Patients with Obesity Undergoing Bariatric Surgery: A Cross-Sectional Study

BACKGROUND

Pulmonary atelectasis is present even before surgery in patients with obesity. We aimed to estimate the prevalence and extension of preoperative atelectasis in patients with obesity undergoing bariatric surgery and to determine if variation in preoperative Spo2 values in the seated position at room air is explained by the extent of atelectasis coverage in the supine position.

METHODS

This was a cross-sectional study in a single center specialized in laparoscopic bariatric surgery. Preoperative chest computed tomographies were reassessed by a senior radiologist to quantify the extent of atelectasis coverage as a percentage of total lung volume. Patients were classified as having atelectasis when the affection was ≥2.5%, to estimate the prevalence of atelectasis. Crude and adjusted prevalence ratios (aPRs) and odds ratios (aORs) were obtained to assess the relative prevalence of atelectasis and percentage coverage, respectively, with increasing obesity category. Inverse probability weighting was used to assess the total, direct (not mediated), and indirect (mediated through atelectasis) effects of body mass index (BMI) on preoperative Spo2, and to quantify the magnitude of mediation (proportion mediated). E-values were calculated, to represent the minimum magnitude of association that an unmeasured confounder with the same directionality of the effect should have to drive the observed point estimates or lower confidence intervals (CIs) to 1, respectively.

RESULTS

In 236 patients with a median BMI of 40.3 kg/m2 (interquartile range [IQR], 34.6-46.0, range: 30.0-77.3), the overall prevalence of atelectasis was 32.6% (95% CI, 27.0-38.9) and by BMI category: 30 to 35 kg/m2, 12.7% (95% CI, 6.1-24.4); 35 to 40 kg/m2, 28.3% (95% CI, 17.2-42.6); 40 to 45 kg/m2, 12.3% (95% CI, 5.5-24.3); 45 to 50 kg/m2, 48.4% (95% CI, 30.6-66.6); and ≥50 units, 100% (95% CI, 86.7-100). Compared to the 30 to 35 kg/m2 group, only the categories with BMI ≥45 kg/m2 had significantly higher relative prevalence of atelectasis-45 to 50 kg/m2, aPR = 3.52 (95% CI, 1.63-7.61, E-value lower bound: 2.64) and ≥50 kg/m2, aPR = 8.0 (95% CI, 4.22-15.2, E-value lower bound: 7.91)-and higher odds of greater atelectasis percentage coverage: 45-50 kg/m2, aOR = 7.5 (95% CI, 2.7-20.9) and ≥50 kg/m2, aOR = 91.5 (95% CI, 30.0-279.3). Atelectasis percent alone explained 70.2% of the variation in preoperative Spo2. The proportion of the effect of BMI on preoperative Spo2 values <96% mediated through atelectasis was 81.5% (95% CI, 56.0-100).

CONCLUSIONS

The prevalence and extension of atelectasis increased with higher BMI, being significantly higher at BMI ≥45 kg/m2. Preoperative atelectasis mediated the effect of BMI on Spo2 at room air in the seated position.

Positive end-expiratory pressure and postoperative pulmonary complications in laparoscopic bariatric surgery: systematic review and meta-analysis

BACKGROUND

This study compares the effect of positive end-expiratory pressure (PEEP) on postoperative pulmonary complications (PPCs) in patients with obesity undergoing laparoscopic bariatric surgery (LBS) under general anesthesia with mechanical ventilation.

METHODS

A comprehensive search was conducted in PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, China National Knowledge Internet, Wanfang database, and Google Scholar for studies published up to July 29, 2023, without time or language restrictions. The search terms included "PEEP," "laparoscopic," and "bariatric surgery." Randomized controlled trials comparing different levels of PEEP or PEEP with zero-PEEP (ZEEP) in patients with obesity undergoing LBS were included. The primary outcome was a composite of PPCs, and the secondary outcomes were intraoperative oxygenation, respiratory compliance, and mean arterial pressure (MAP). A fixed-effect or random-effect model was selected for meta-analysis based on the heterogeneity of the included studies.

RESULTS

Thirteen randomized controlled trials with a total of 708 participants were included for analysis. No statistically significant difference in PPCs was found between the PEEP and ZEEP groups (risk ratio = 0.27, 95% CI: 0.05-1.60; p = 0.15). However, high PEEP ≥ 10 cm H2O significantly decreased PPCs compared with low PEEP < 10 cm H2O (risk ratio = 0.20, 95% CI: 0.05-0.89; p = 0.03). The included studies showed no significant heterogeneity (I2 = 20% & 0%). Compared with ZEEP, PEEP significantly increased intraoperative oxygenation and respiratory compliance (WMD = 74.97 mm Hg, 95% CI: 41.74-108.21; p < 0.001 & WMD = 9.40 ml cm H2O- 1, 95% CI: 0.65-18.16; p = 0.04). High PEEP significantly improved intraoperative oxygenation and respiratory compliance during pneumoperitoneum compared with low PEEP (WMD = 66.81 mm Hg, 95% CI: 25.85-107.78; p = 0.001 & WMD = 8.03 ml cm H2O- 1, 95% CI: 4.70-11.36; p < 0.001). Importantly, PEEP did not impair hemodynamic status in LBS.

CONCLUSIONS

In patients with obesity undergoing LBS, high PEEP ≥ 10 cm H2O could decrease PPCs compared with low PEEP < 10 cm H2O, while there was a similar incidence of PPCs between PEEP (8-10 cm H2O) and the ZEEP group. The application of PEEP in ventilation strategies increased intraoperative oxygenation and respiratory compliance without affecting intraoperative MAP. A PEEP of at least 10 cm H2O is recommended to reduce PPCs in patients with obesity undergoing LBS.

REGISTRATION NUMBER

CRD42023391178 in PROSPERO.

Weaning from mechanical ventilation in the operating room: a systematic review

BACKGROUND

Postoperative pulmonary complications (PPCs) are associated with postoperative mortality and prolonged hospital stay. Although intraoperative mechanical ventilation (MV) is a risk factor for PPCs, strategies addressing weaning from MV are understudied. In this systematic review, we evaluated weaning strategies and their effects on postoperative pulmonary outcomes.

METHODS

Our protocol was registered on PROSPERO (CRD42022379145). Eligible studies included randomised controlled trials and observational studies of adults weaned from MV in the operating room. Primary outcomes included atelectasis and oxygenation; secondary outcomes included lung volume changes and PPCs. Risk of bias was assessed using the Cochrane Risk of Bias (RoB2) tool, and quality of evidence with the GRADE framework.

RESULTS

Screening identified 14 randomised controlled trials including 1719 patients; seven studies were limited to the weaning phase and seven included interventions not restricted to the weaning phase. Strategies combining pressure support ventilation (PSV) with positive end-expiratory pressure (PEEP) and low fraction of inspired oxygen (FiO2) improved atelectasis, oxygenation, and lung volumes. Low FiO2 improved atelectasis and oxygenation but might not improve lung volumes. A fixed-PEEP strategy led to no improvement in oxygenation or atelectasis; however, individualised PEEP with low FiO2 improved oxygenation and might be associated with reduced PPCs. Half of included studies are of moderate or high risk of bias; the overall quality of evidence is low.

CONCLUSIONS

There is limited research evaluating weaning from intraoperative MV. Based on low-quality evidence, PSV, individualised PEEP, and low FiO2 may be associated with reduced postoperative pulmonary outcomes.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42022379145).

A stepwise lung recruitment maneuver using I-gel can improve respiratory parameters: A prospective observational study

I-gel has been used in various clinical situations. The study investigated alterations in respiratory parameters following a stepwise lung recruitment maneuver (LRM) using the i-gel. The research involved 60 patients classified as American Society of Anesthesiologists class I-II, aged 30 to 75 years, undergoing elective urologic surgery. Various respiratory parameters, including lung compliance, airway resistance, leak volume, airway pressure, and oxygen reserve index, were recorded at different time points: before LRM, immediately after LRM, and at 5, 15, and 30 minutes after LRM, as well as at the end of the surgery. The primary outcome was to assess an improvement in lung compliance. Dynamic lung compliance (mean ± SD) was significantly increased from 49.2 ± 1.8 to 70.15 ± 3.2 mL/cmH2O (P < .05) after LRM. Static lung compliance (mean ± SD) was increased considerably from 52.4 ± 1.7 to 65.0 ± 2.5 mL/cmH2O (P < .05) after the LRM. Both parameters maintained a statistically significant increased status for a certain period compared to baseline despite a decreased degree of increment. Airway resistance (mean ± SD) was significantly reduced after the LRM from 12.05 ± 0.56 to 10.41 ± 0.64 L/cmH2O/s (P < .05). Stepwise LRM using i-gel may improve lung compliance and airway resistance. Repeated procedures could lead to prolonged improvements in respiratory parameters.

Continuous positive airway pressure is unsafe for radiofrequency ablation of lung cancer under sedation: a randomised controlled trial

OBJECTIVE

To evaluate the safety of a minimum continuous positive airway pressure of 4 cmH2O (CPAP + 4) during computed tomography (CT)-guided radiofrequency ablation (RFA) for lung malignancies under procedural sedation and analgesia (PSA).

METHODS

This was a prospective, randomised, single-blind, parallel-group, placebo-controlled trial with an open-label medical device conducted at a single tertiary university hospital in Barcelona, Spain. Forty-six patients over 18 years of age scheduled for CT-guided RFA of a malignant pulmonary tumour under PSA were randomised to receive either CPAP + 4 or a modified mask for placebo CPAP (Sham-CPAP). Exclusion criteria included contraindications for RFA, refusal to participate, inability to understand the procedure or tolerate the CPAP test, lung biopsy just prior to RFA, intercurrent diseases, or previous randomisation for additional pulmonary RFA. Primary outcomes were the percentage of patients reporting at least one serious adverse event (SAE), classification for complications from the Cardiovascular and Interventional Radiological Society of Europe (CIRSE), and Clavien-Dindo classifications for complications, hospital stay, and readmissions. Secondary outcomes included adverse events (AEs), respiratory parameters, airway management, and the local radiological efficacy of pulmonary ablation.

RESULTS

CPAP + 4 prolonged hospital stay (1.5 ± 1.1 vs. 1.0 ± 0 inpatient nights, p = 0.022) and increased the risk of AE post-RFA (odds ratio (95% CI): 4.250 (1.234 to 14.637), p = 0.021 with more pneumothorax cases (n = 5/22, 22.7% vs. n = 0/24, 0%, p = 0.019). Per-protocol analysis revealed more SAEs and CIRSE grade 3 complications in the CPAP + 4 group (23.5% vs. 0%, p = 0.036). No significant differences were found in the effectiveness of oxygenation, ventilation, or pulmonary ablation.

CONCLUSION

CPAP is unsafe during CT-guided RFA for lung cancer under PSA even at the lowest pressure setting.

TRIAL REGISTRATION

ClinicalTrials.Gov, ClinicalTrials.gov ID NCT02117908, Registered 11 April 2014, https://www.

CLINICALTRIALS

gov/study/NCT02117908 CRITICAL RELEVANCE STATEMENT: This study highlights the hazards of continuous positive airway pressure during radiofrequency ablation of lung cancer, even at minimal pressures, deeming it unsafe under procedural sedation and analgesia in pulmonary interventional procedures. Findings provide crucial insights to prioritise patient safety.

KEY POINTS

No prior randomised controlled trials on CPAP safety in percutaneous lung thermo-ablation. Standardised outcome measures are crucial for radiology research. CPAP during lung RFA raises hospital stay and the risk of complications. CPAP is unsafe during CT-guided RFA of lung cancer under procedural sedoanalgesia.

Obesity and anesthesia

PURPOSE OF REVIEW

Surgical procedures on obese patients are dramatically increasing worldwide over the past few years. In this review, we discuss the physiopathology of predominantly respiratory system in obese patients, the importance of preoperative evaluation, preoxygenation and intraoperative positive end expiratory pressure (PEEP) titration to prevent pulmonary complications and the optimization of airway management and oxygenation to reduce or prevent postoperative respiratory complications.

RECENT FINDINGS

Many patients are coming to preoperative clinic with medication history of glucagon-like-peptide 1 agonists ( GLP-1) agonists and it has raised many questions regarding Nil Per Os (NPO)/perioperative fasting guidelines due to delayed gastric emptying caused by these medications. American Society of Anesthesiologists (ASA) has come up with guiding document to help with such situations. Ambulatory surgery centers are doing more obesity cases in a safe manner which were deemed unsafe at one point . Quantitative train of four (TOF) monitoring, better neuromuscular reversal agents and gastric ultrasounds seemed to have made a significant impact in the care of obese patients in the perioperative period.

SUMMARY

Obese patients are at higher risk of perioperative complications, mainly associated with those related to the respiratory function. An appropriate preoperative evaluation, intraoperative management, and postoperative support and monitoring is essential to improve outcome and increase the safety of the surgical procedure.

Electrical Impedance Tomography-based Ventilation Patterns in Patients after Major Surgery

Rationale: General anesthesia and mechanical ventilation have negative impacts on the respiratory system, causing heterogeneous distribution of lung aeration, but little is known about the ventilation patterns of postoperative patients and their association with clinical outcomes. Objectives: To clarify the phenotypes of ventilation patterns along a gravitational direction after surgery by using electrical impedance tomography (EIT) and to evaluate their association with postoperative pulmonary complications (PPCs) and other relevant clinical outcomes. Methods: Adult postoperative patients at high risk for PPCs, receiving mechanical ventilation on ICU admission (N = 128), were prospectively enrolled between November 18, 2021 and July 18, 2022. PPCs were prospectively scored until hospital discharge, and their association with phenotypes of ventilation patterns was studied. The secondary outcomes were the times to wean from mechanical ventilation and oxygen use and the length of ICU stay. Measurements and Main Results: Three phenotypes of ventilation patterns were revealed by EIT: phenotype 1 (32% [n = 41], a predominance of ventral ventilation), phenotype 2 (41% [n = 52], homogeneous ventilation), and phenotype 3 (27% [n = 35], a predominance of dorsal ventilation). The median PPC score was higher in phenotype 1 and phenotype 3 than in phenotype 2. The median time to wean from mechanical ventilation was longer in phenotype 1 versus phenotype 2. The median duration of ICU stay was longer in phenotype 1 versus phenotype 2. The median time to wean from oxygen use was longer in phenotype 1 and phenotype 3 than in phenotype 2. Conclusions: Inhomogeneous ventilation patterns revealed by EIT on ICU admission were associated with PPCs, delayed weaning from mechanical ventilation and oxygen use, and a longer ICU stay.

Erector spinae plane block reduces opioid consumption and improves incentive spirometry volume after cardiac surgery: A retrospective cohort study

BACKGROUND

Effective postoperative pain management is vital in cardiac surgery to prevent opioid dependency and respiratory complications. Previous studies on the erector spinae plane (ESP) block have focused on single-shot applications or immediate postoperative outcomes. This study evaluates the efficacy of continuous ESP block vs conventional care in reducing opioid consumption and enhancing respiratory function recovery postcardiac surgery over 72 hours.

METHODS

A retrospective study at a tertiary hospital (January 2021-July 2022) included 262 elective cardiac surgery patients. Fifty-three received a preoperative ESP block, matched 1:1 with a control group (n = 53). The ESP group received 0.5% ropivacaine intraoperatively and 0.16% ropivacaine every 4 hours postoperatively. Outcomes measured were cumulative oral morphine equivalent (OME) dose within 72 hours postextubation, daily maximum numerical rating scale (NRS) ≥3, incentive spirometry volume, and %baseline performance, stratified by surgery type (sternotomy or thoracotomy).

RESULTS

Significant OME reduction was observed in the ESP group (sternotomy: median decrease of 113 mg, 95% CI: 60-157.5 mg, p < 0.001; thoracotomy: 172.5 mg, 95% CI: 45-285 mg, p = 0.010). The ESP group also had a lower risk of daily maximum NRS ≥3 (adjusted OR sternotomy: 0.22, p < 0.001; thoracotomy: 0.07, p < 0.001), a higher incentive spirometry volumes (sternotomy: mean increase of 149 mL, p = 0.019; thoracotomy: 521 mL, p = 0.017), and enhanced spirometry %baseline (sternotomy: mean increase of 11.5%, p = 0.014; thoracotomy: 26.5%, p < 0.001).

CONCLUSION

Continuous ESP block was associated with a reduction of postoperative opioid requirements, lower instances of pain scores ≥3, and improve incentive spirometry performance following cardiac surgery. These benefits appear particularly prominent in thoracotomy patients. Further prospective studies with larger sample size are required to validate these findings.

Noninvasive respiratory support in the perioperative setting: a narrative review

The application of preoperative noninvasive respiratory support (NRS) has been expanding with increasing recognition of its potential role in this setting as a physiological optimization for patients with a high risk of developing atelectasis and postoperative pulmonary complications (PPC). The increased availability of high-performance anesthesia ventilator machines providing an easy way for NRS support in patients with reduced lung function should not be under-evaluated. This support can reduce hypoxia, restore lung volumes and theoretically reduce atelectasis formation after general anesthesia. Therapeutic purposes should also be considered in the perioperative setting, such as preoperative NRS to optimize treatment of patients' pre-existing diseases, e.g., sleep-disordered breathing. Finally, the recent guidelines for airway management suggest preoperative NRS application before anesthesia induction in difficult airway management to prolong the time needed to secure the airway with an orotracheal tube. This narrative review aims to revise all these aspects and to provide some practical notes to maximize the efficacy of perioperative noninvasive respiratory support.

Influence of Fractional Inspired Oxygen Tension on Lung Perfusion Distribution, Regional Ventilation, and Lung Volume during Mechanical Ventilation of Supine Healthy Swine

BACKGROUND

Lower fractional inspired oxygen tension (Fio2) during general anesthesia can reduce lung atelectasis. The objectives are to evaluate the effect of two Fio2 (0.4 and 1) during low positive end-expiratory pressure (PEEP) ventilation over lung perfusion distribution, volume, and regional ventilation. These variables were evaluated at two PEEP levels and unilateral lung atelectasis.

METHODS

In this exploratory study, 10 healthy female piglets (32.3 ± 3.4 kg) underwent mechanical ventilation in two atelectasis models: (1) bilateral gravitational atelectasis (n = 6), induced by changes in PEEP and Fio2 in three combinations: high PEEP with low Fio2 (Fio2 = 0.4), zero PEEP (PEEP0) with low Fio2 (Fio2 = 0.4), and PEEP0 with high Fio2 (Fio2 = 1); and (2) unilateral atelectasis (n = 6), induced by left bronchial occlusion, with the left lung aerated (Fio2 = 0.21) and low aerated (Fio2 = 1; n = 5 for this step). Measurements were conducted after 10 min in each step, encompassing assessment of respiratory mechanics, oxygenation, and hemodynamics; lung ventilation and perfusion by electrical impedance tomography; and lung aeration and perfusion by computed tomography.

RESULTS

During bilateral gravitational atelectasis, PEEP reduction increased atelectasis in dorsal regions, decreased respiratory compliance, and distributed lung ventilation to ventral regions with a parallel shift of perfusion to the same areas. With PEEP0, there were no differences between low and high Fio2 in respiratory compliance (23.9 ± 6.5 ml/cm H2O vs. 21.9 ± 5.0; P = 0.441), regional ventilation, and regional perfusion, despite higher lung collapse (18.6 ± 7.6% vs. 32.7 ± 14.5%; P = 0.045) with high Fio2. During unilateral lung atelectasis, the deaerated lung had a lower shunt (19.3 ± 3.6% vs. 25.3 ± 5.5%; P = 0.045) and lower computed tomography perfusion to the left lung (8.8 ± 1.8% vs. 23.8 ± 7.1%; P = 0.007).

CONCLUSIONS

PEEP0 with low Fio2, compared with high Fio2, did not produce significant changes in respiratory system compliance, regional lung ventilation, and perfusion despite significantly lower lung collapse. After left bronchial occlusion, the shrinkage of the parenchyma with Fio2 = 1 enhanced hypoxic pulmonary vasoconstriction, reducing intrapulmonary shunt and perfusion of the nonventilated areas.

EDITOR’S PERSPECTIVE

Respiratory effects of pressure support ventilation in spontaneously breathing patients under anaesthesia: Randomised controlled trial

BACKGROUND

Lung volume loss is a major risk factor for postoperative respiratory complications after general anaesthesia and mechanical ventilation. We hypothesise that spontaneous breathing without pressure support may enhance the risk for atelectasis development. Therefore, we aimed at characterising whether pressure support prevents changes in lung function in patients breathing spontaneously through laryngeal mask airway.

METHODS

In this randomised controlled trial, adult female patients scheduled for elective gynaecological surgery in lithotomy position were randomly assigned to the continuous spontaneous breathing group (CSB, n = 20) or to the pressure support ventilation group (PSV, n = 20) in a tertiary university hospital. Lung function measurements were carried out before anaesthesia and 1 h postoperatively by a researcher blinded to the group allocation. Lung clearance index calculated from end-expiratory lung volume turnovers as primary outcome variable was assessed by the multiple-breath nitrogen washout technique (MBW). Respiratory mechanics were measured by forced oscillations to assess parameters reflecting the small airway function and respiratory tissue stiffness.

RESULTS

MBW was successfully completed in 18 patients in both CSB and PSV groups. The decrease in end-expiratory lung volume was more pronounced in the CSB than that in the PSV group (16.6 ± 6.6 [95% CI] % vs. 7.6 ± 11.1%, p = .0259), with no significant difference in the relative changes of the lung clearance index (-0.035 ± 7.1% vs. -0.18 ± 6.6%, p = .963). The postoperative changes in small airway function and respiratory tissue stiffness were significantly lower in the PSV than in the CSB group (p < .05 for both).

CONCLUSIONS

These results suggest that pressure support ventilation protects against postoperative lung-volume loss without affecting ventilation inhomogeneity in spontaneously breathing patients with increased risk for atelectasis development.

TRIAL REGISTRATION

NCT02986269.

Intraoperative Mechanical Power and Postoperative Pulmonary Complications in Noncardiothoracic Elective Surgery Patients: A 10-Year Retrospective Cohort Study

BACKGROUND

Postoperative pulmonary complications is a major issue that affects outcomes of surgical patients. The hypothesis was that the intraoperative ventilation parameters are associated with occurrence of postoperative pulmonary complications.

METHODS

A single-center retrospective cohort study was conducted at the Lille University Hospital, France. The study included 33,701 adults undergoing noncardiac, nonthoracic elective surgery requiring general anesthesia with tracheal intubation between January 2010 and December 2019. Intraoperative ventilation parameters were compared between patients with and without one or more postoperative pulmonary complications (respiratory infection, respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm, and aspiration pneumonitis) within 7 days of surgery.

RESULTS

Among 33,701 patients, 2,033 (6.0%) had one or more postoperative pulmonary complications. The lower tidal volume to predicted body weight ratio (odds ratio per -1 ml·kgPBW-1, 1.08; 95% CI, 1.02 to 1.14; P < 0.001), higher mechanical power (odds ratio per 4 J·min-1, 1.37; 95% CI, 1.26 to 1.49; P < 0.001), dynamic respiratory system compliance less than 30 ml·cm H2O (1.30; 95% CI, 1.15 to 1.46; P < 0.001), oxygen saturation measured by pulse oximetry less than 96% (odds ratio, 2.42; 95% CI, 1.97 to 2.96; P < 0.001), and lower end-tidal carbon dioxide (odds ratio per -3 mmHg, 1.06; 95% CI, 1.00 to 1.13; P = 0.023) were independently associated with postoperative pulmonary complications. Patients with postoperative pulmonary complications were more likely to be admitted to the intensive care unit (odds ratio, 12.5; 95% CI, 6.6 to 10.1; P < 0.001), had longer hospital length of stay (subhazard ratio, 0.43; 95% CI, 0.40 to 0.45), and higher in-hospital (subhazard ratio, 6.0; 95% CI, 4.1 to 9.0; P < 0.001) and 1-yr mortality (subhazard ratio, 2.65; 95% CI, 2.33 to 3.02; P < 0.001).

CONCLUSIONS

In the study's population, decreased rather than increased tidal volume, decreased compliance, increased mechanical power, and decreased end-tidal carbon dioxide were independently associated with postoperative pulmonary complications.

EDITOR’S PERSPECTIVE

High flow nasal oxygen vs. conventional oxygen therapy over respiratory oxygenation index after esophagectomy: an observational study

Background

Postoperative pulmonary complications after esophagectomy still represent a matter of concern. High flow nasal cannula (HFNC) early after major abdominal and thoracic surgery has demonstrated some advantages over conventional oxygen therapy. Data about respiratory effect of HFNC after esophagectomy is scarce. The primary aim of this study is to investigate if the early use of HFNC after esophagectomy could enhance patients' postoperative respiratory oxygenation (ROX) index and, ultimately, reduce postoperative pneumonia.

Methods

In this single center retrospective study all patients undergoing to esophagectomy for cancer from May 2020 to November 2022 were evaluated. Historical cohort (HC) received postoperative oxygen supplementation with Venturi mask or nasal goggles, and a cohort was put under HFNC (HFNC cohort). ROX index, blood gas analysis, radiological atelectasis score (RAS), post-operative complications' data and information on hospital stay have been collected and analyzed.

Results

Seventy-one patients were included for the final statistical analysis, 31 in the HFNC and 40 in the HC cohort. Mean age was 64±10 years and body mass index (BMI) was 26 [24-29] kg/m2. ROX index was higher in the HFNC patients than in the HC, 20.8 [16.7-25.9] vs. 14.9 [10.8-18.2] (P<0.0001). In the HFNC cohort patients, pH was higher, 7.42 [7.40-7.44] vs. 7.39 [7.37-7.43] than HC, while PaCO2 was lower in HFNC cohort compared with HC, 39 [36-41] vs. 42 [39-45] mmHg, respectively (P=0.01). RAS was similar between the two cohorts of patients, 1.5±0.98 vs. 1.4±1.04 in the HFNC and the HC cohort, respectively (P=0.611). Lower acute respiratory failure (ARF) rate was recorded among HFNC than HC cohort, 0% vs. 13% respectively, P=0.06. No difference in pneumonia frequency between two cohorts was shown.

Conclusions

HFNC improved the ROX index after esophagectomy through significant respiratory rate reduction. This tool should be considered for early respiratory support after extubation in this category of patients, not only as a rescue therapy for ARF, but also to optimize early postoperative respiratory function. Whether this will improve patients' outcomes requires further large randomized controlled trials.

Effect of ultrasound-guided transversus abdominis plane block in reducing atelectasis after laparoscopic surgery in children: A randomized clinical trial

Background

Atelectasis is a commonly observed postoperative complication of general anesthesia in children. Pulmonary protective ventilation strategies have been reported to have a beneficial effect on postoperative atelectasis in children. Therefore, the present study aimed to evaluate the efficacy of the ultrasound-guided transversus abdominis plane (TAP) block technique in preventing the incidence of postoperative atelectasis in children.

Materials and methods

This study enrolled 100 consecutive children undergoing elective laparoscopic bilateral hernia repair and randomly divided them into the control and TAP groups. Conventional lung-protective ventilation was initiated in both groups after the induction of general anesthesia. The children in the TAP group received an ultrasound-guided TAP block with 0.3 mL/kg of 0.5% ropivacaine after the induction of anesthesia.

Results

Anesthesia-induced atelectasis was observed in 24% and 84% of patients in the TAP (n = 50) and control (n = 50) groups, respectively, before discharge from the post-anesthetic care unit (T3; PACU) (odds ratio [OR], 0.062; 95% confidence interval [CI], 0.019-0.179; P < 0.001). No significant difference was observed between the control and TAP groups in terms of the lung ultrasonography (LUS) scores 5 min after endotracheal intubation (T1). However, the LUS scores were lower in the TAP group than those in the control group at the end of surgery (T2, P < 0.01) and before discharge from the PACU (T3, P < 0.001). Moreover, the ace, legs, activity, cry and consolability (FLACC) pain scores in the TAP group were lower than those in the control group at each postoperative time point.

Conclusion

Ultrasound-guided TAP block effectively reduced the incidence of postoperative atelectasis and alleviated pain in children undergoing laparoscopic surgery.

Stubborn hypoxemia after mild to moderate sedation and analgesia: A case report

INTRODUCTION

Atelectasis typically denotes the partial or complete collapse of lung segments, lobes, or lobules in individuals, leading to a compromised respiratory function. The prevalence of perioperative atelectasis may be significantly underestimated, particularly among patients subjected to general anesthesia.

PATIENT CONCERNS

This article conducts a retrospective analysis of a case involving refractory hypoxemia in a patient with a liver tumor who was admitted to Yanbian University Affiliated Hospital (Yanbian Hospital) after undergoing mild-to-moderate sedation and analgesia outside the operating room.

DIAGNOSIS

Based on the results of CT examination and present history, the patient was diagnosed with intraoperative atelectasis.

INTERVENTION

After the surgery, the patient was transferred to the recovery ward, where nasal oxygen therapy and nebulized inhalation treatment were administered. Vital signs were closely monitored at the bedside, gradually returning to the preoperative baseline.

OUTCOME

Postoperatively, the patient developed atelectasis, with the percentage of lung opacity shown in the image decreasing from 9.2% of the total thoracic cage area to 8.4%.

CONCLUSION

During non-intubated intravenous anesthesia, patients with compromised pulmonary conditions are more susceptible to refractory hypoxemia. Therefore, a personalized approach should be adopted regarding oxygen concentration and the dosage and type of medication. Additionally, preparations for appropriate airway management measures are essential to safeguard patient safety in the event of respiratory issues.

Change in stroke volume during alveolar recruitment maneuvers through transient continuous positive airway pressure or stepwise increase in positive end expiratory pressure in anesthetized patients: a prospective randomized double-blind study

PURPOSE

Intraoperative alveolar recruitment maneuvers (ARM) used during protective ventilation strategy may have severe adverse hemodynamic effects, reported mainly during abrupt continuous positive airway pressure (CPAP). Stepwise increase and decrease in positive end expiratory pressure (PEEP) may be used. We compared the hemodynamic effects of these two maneuvers.

METHODS

We enrolled patients scheduled for intermediate to high-risk surgery with continuous arterial pressure and stroke volume (esophageal Doppler) monitoring in a prospective, single-centre, randomized, double-blind study. After induction of anesthesia, we ensured preload independence of stroke volume before an ARM was randomly performed: 30 cm H2O CPAP for 30 sec (CPAP group) or stepwise increase in PEEP from 8 to 20 cm H2O with inspiratory pressure of 10 cm H2O followed by a stepwise decrease in PEEP from 20 to 8 cm H2O (STEP group). The primary outcome was the relative variation in stroke volume.

RESULTS

Thirty-five patients were included in the CPAP and STEP groups. Mean (standard deviation) relative variation in stroke volume was -57 (24)% in the CPAP group and -32 (24)% in the STEP group (difference, -25; 95% confidence interval, -37 to -14; P < 0.001). Changes in systolic, mean, and diastolic arterial pressure over time were not different between groups. The ARM was stopped because of a systolic arterial pressure < 70 mm Hg in four patients in the CPAP group and in one patient in the STEP group.

CONCLUSIONS

Alveolar recruitment maneuvers through stepwise increase and decrease in PEEP have a better hemodynamic tolerance than transient CPAP.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04802421); first submitted 15 March 2021.

Estimation of normal lung weight index in healthy female domestic pigs

INTRODUCTION

Lung weight is an important study endpoint to assess lung edema in porcine experiments on acute respiratory distress syndrome and ventilatory induced lung injury. Evidence on the relationship between lung-body weight relationship is lacking in the literature. The aim of this work is to provide a reference equation between normal lung and body weight in female domestic piglets.

MATERIALS AND METHODS

177 healthy female domestic piglets from previous studies were included in the analysis. Lung weight was assessed either via a CT-scan before any experimental injury or with a scale after autopsy. The animals were randomly divided in a training (n = 141) and a validation population (n = 36). The relation between body weight and lung weight index (lung weight/body weight, g/kg) was described by an exponential function on the training population. The equation was tested on the validation population. A Bland-Altman analysis was performed to compare the lung weight index in the validation population and its theoretical value calculated with the reference equation.

RESULTS

A good fit was found between the validation population and the exponential equation extracted from the training population (RMSE = 0.060). The equation to determine lung weight index from body weight was: [Formula: see text] At the Bland and Altman analyses, the mean bias between the real and the expected lung weight index was - 0.26 g/kg (95% CI - 0.96-0.43), upper LOA 3.80 g/kg [95% CI 2.59-5.01], lower LOA - 4.33 g/kg [95% CI = - 5.54-(- 3.12)].

CONCLUSIONS

This exponential function might be a valuable tool to assess lung edema in experiments involving 16-50 kg female domestic piglets. The error that can be made due to the 95% confidence intervals of the formula is smaller than the one made considering the lung to body weight as a linear relationship.

Perioperative Diaphragm Dysfunction

Diaphragm Dysfunction (DD) is a respiratory disorder with multiple causes. Although both unilateral and bilateral DD could ultimately lead to respiratory failure, the former is more common. Increasing research has recently delved into perioperative diaphragm protection. It has been established that DD promotes atelectasis development by affecting lung and chest wall mechanics. Diaphragm function must be specifically assessed for clinicians to optimally select an anesthetic approach, prepare for adequate monitoring, and implement the perioperative plan. Recent technological advancements, including dynamic MRI, ultrasound, and esophageal manometry, have critically aided disease diagnosis and management. In this context, it is noteworthy that therapeutic approaches for DD vary depending on its etiology and include various interventions, either noninvasive or invasive, aimed at promoting diaphragm recruitment. This review aims to unravel alternative anesthetic and operative strategies that minimize postoperative dysfunction by elucidating the identification of patients at a higher risk of DD and procedures that could cause postoperative DD, facilitating the recognition and avoidance of anesthetic and surgical interventions likely to impair diaphragmatic function.

Severity of Atelectasis during Bronchoscopy: Descriptions of a New Grading System (AtelectasisSeverity Scoring System-"ASSESS") and At-Risk-Lung Zones

Atelectasis during bronchoscopy under general anesthesia is very common and can have a detrimental effect on navigational and diagnostic outcomes. While the intraprocedural incidence and anatomic location have been previously described, the severity of atelectasis has not. We reviewed chest CT images of patients who developed atelectasis in the VESPA trial (Ventilatory Strategy to Prevent Atelectasis). By drawing boundaries at the posterior chest wall (A), the anterior aspect of the vertebral body (C), and mid-way between these two lines (B), we delineated at-risk lung zones 1, 2, and 3 (from posterior to anterior). An Atelectasis Severity Score System ("ASSESS") was created, classifying atelectasis as "mild" (zone 1), "moderate" (zones 1-2), and "severe" (zones 1-2-3). A total of 43 patients who developed atelectasis were included in this study. A total of 32 patients were in the control arm, and 11 were in the VESPA arm; 20 patients (47%) had mild atelectasis, 20 (47%) had moderate atelectasis, and 3 (6%) had severe atelectasis. A higher BMI was associated with increased odds (1.5 per 1 unit change; 95% CI, 1.10-2.04) (p = 0.0098), and VESPA was associated with decreased odds (0.05; 95% CI, 0.01-0.47) (p = 0.0080) of developing moderate to severe atelectasis. ASSESS is a simple method used to categorize intra-bronchoscopy atelectasis, which allows for a qualitative description of this phenomenon to be developed. In the VESPA trial, a higher BMI was not only associated with increased incidence but also increased severity of atelectasis, while VESPA had the opposite effect. Preventive strategies should be strongly considered in patients with risk factors for atelectasis who have lesions located in zones 1 and 2, but not in zone 3.

Effects of "Timing It Right" nursing on clinical outcome and psychological resilience for lung cancer patients undergoing radical thoracoscopic surgery

AIM

To investigate the effects of "Timing It Right (TIR)" nursing on clinical outcome and psychological resilience in lung cancer patients undergoing radical thoracoscopic surgery.

METHODS

In this retrospective study, 60 patients from January 2022 to June 2023 were studied. Among them, observation group received TIR intervention (n = 34), while control group received routine nursing intervention (n = 26). The self-care ability, psychological resilience, quality of life (QoL), postoperative recovery, postoperative complications, and postoperative pulmonary function recovery were compared between the two groups.

RESULTS

The scores of ESCA (Exercise of Self-Care Agency) and CD-RISC (Connor-Davidson Resilience Scale), lung function, and QoL-C30 in observation group were significantly higher than those in control group after discharge, while the incidence of postoperative complications in observation group was significantly lower than that in the control group (all P<0.05). Furthermore, time to first bedtime activity and chest drain removal, and the length of postoperative hospitalization in the observation group were obviously shorter than those in the control group (all P<0.05).

CONCLUSION

TIR nursing can effectively enhance the self-care ability of lung cancer patients undergoing radical thoracoscopic surgery, improve their psychological elasticity, enhance their quality of life, shorten the hospitalization time, and reduce the incidence of adverse reactions.

Doppler images of intrapulmonary arteries within atelectasis and its impact on right ventricular afterload with transesophageal echocardiography

Video-assisted thoracoscopy (VATS) cardiac surgery requires one-lung ventilation (OLV) and transoesophageal ultrasound (TOE) monitoring. Colour and spectral Doppler make it possible to study the pattern of blood flow in the pulmonary vessels within the atelectatic lung. In this case report we describe how TOE can be used to detect blood flow within the atelectatic lung and to assess pulmonary vascular resistance (PVR) and right ventricular (RV) afterload. FINDINGS: Three anaesthetised, mechanically ventilated adults scheduled for cardiac surgery by VATS were scanned with TOE. After left OLV, the transducer was rotated away from the heart to obtain 2D colour Doppler images of blood flow within the consolidated lung parenchyma. We were able to identify the flow pattern of the intrapulmonary branches of the pulmonary artery. PVR was recorded using pulsed cardiac Doppler at baseline, after induction of general anaesthesia, 20 min after OLV and at the end of OLV, and after performing an alveolar recruitment manoeuvre (ARM) that led to complete resolution of the aforementioned consolidation. CONCLUSIONS: TOE is a semi-invasive imaging tool that can be used to diagnose and study PVR-induced atelectasis and to analyse the resulting pulmonary shunt and its possible effect on PVR.