Mechanical Power Density Predicts Prolonged Ventilation Following Double Lung Transplantation

Prolonged mechanical ventilation (PMV) after lung transplantation poses several risks, including higher tracheostomy rates and increased in-hospital mortality. Mechanical power (MP) of artificial ventilation unifies the ventilatory variables that determine gas exchange and may be related to allograft function following transplant, affecting ventilator weaning. We retrospectively analyzed consecutive double lung transplant recipients at a national transplant center, ventilated through endotracheal tubes upon ICU admission, excluding those receiving extracorporeal support. MP and derived indexes assessed up to 36 h after transplant were correlated with invasive ventilation duration using Spearman's coefficient, and we conducted receiver operating characteristic (ROC) curve analysis to evaluate the accuracy in predicting PMV (>72 h), expressed as area under the ROC curve (AUROC). PMV occurred in 82 (35%) out of 237 cases. MP was significantly correlated with invasive ventilation duration (Spearman's ρ = 0.252 [95% CI 0.129-0.369], p < 0.01), with power density (MP normalized to lung-thorax compliance) demonstrating the strongest correlation (ρ = 0.452 [0.345-0.548], p < 0.01) and enhancing PMV prediction (AUROC 0.78 [95% CI 0.72-0.83], p < 0.01) compared to MP (AUROC 0.66 [0.60-0.72], p < 0.01). Mechanical power density may help identify patients at risk for PMV after double lung transplantation.

Heat and Moisture Exchanger Occlusion Leading to Sudden Increased Airway Pressure: A Case Report Using ChatGPT as a Personal Writing Assistant

Heat and moisture exchangers (HMEs) are commonly used during general anesthesia to provide appropriate humidification and warming of inspired gases. While they play a critical role in mechanical ventilation, they can also lead to acute difficult ventilation if not correctly monitored and drained. We present a case of a 56-year-old female patient who underwent lower extremity vascular bypass surgery under general anesthesia and experienced sudden increased airway pressures due to occlusion of the HME caused by excessive moisture accumulation. Proper monitoring and management of the airway circuit and HMEs can help prevent complications and ensure proper ventilation during surgery. When acute difficult ventilation is encountered during general anesthesia, a systematic approach should be taken to differentiate between patient and external factors. Other differential diagnoses for acute difficult ventilation include bronchospasm, aspiration, endotracheal tube misplacement, pulmonary embolism, and tension pneumothorax. HME occlusion should be considered as part of the differential diagnosis for intraoperative hypoxia. Proactive replacement of HMEs in long cases can prevent occlusion and ensure proper ventilation.

Off-pump versus on-pump coronary artery bypass grafting for octogenarians: A meta-analysis involving 146 372 patients

There is an ongoing debate concerning the optimal surgical option of myocardial revascularization for octogenarians. The current meta‐analysis aimed to compare clinical outcomes following off‐pump coronary artery bypass grafting (OPCABG) or conventional coronary artery bypass grafting (CCABG) in octogenarians. PubMed, Cochrane, Web of Science, and EMBASE databases were searched to identify eligible studies from inception to March 2021. The analysis was performed using STATA 15.1. A literature search yielded 18 retrospective studies involving 146 372 patients (OPCABG = 44 522 vs. CCABG = 101 850). Pooled analysis showed a strong trend toward reducing mortality risk in the OPCABG group (odds ratio: 0.75, 95% confidence interval: 0.56–1.00, p = .05). However, it did not reach statistical significance. The sensitive analysis demonstrated that OPCABG was less likely to cause death than CCABG. There were comparable data in myocardial infarction, renal failure, deep sternal wound infection, and hospital stays between the two groups, although the incidence of stroke, atrial fibrillation, prolonged ventilation, and reoperation for bleeding was significantly lower in the OPCAGB group. OPCABG may be an effective surgical strategy for myocardial revascularization, especially in reducing the incidence of postoperative stroke, atrial fibrillation, prolonged ventilation, and reoperation for bleeding.

Improved survival in children with HPS: Experience from two high volume liver transplant centers across continents

BACKGROUND

Severe HPS increases morbidity and mortality after LT in children. We reviewed the combined experience of LT for HPS in children from two LT centers in Europe and Asia.

METHODS

All children with "proven" HPS as per ERS Task Force criteria (detailed in manuscript) who underwent LT were categorized into M (PaO₂ ≥80 mmHg), Mo (PaO₂  = 60-79 mmHg), S (50-59 mmHg), and VS (PaO₂ <50 mmHg) HPS, based on room air PaO₂ .

RESULTS

Twenty-four children with HPS underwent 25 LT (one re-transplantation) at a median age of 8 years (IQR, 5-12), after a median duration of 8 (4-12) months following HPS diagnosis. Mechanical ventilation was required for a median of 3 (1.5-27) days after LT. Ten children had "S" post-operative hypoxemia, requiring iNO for a median of 5 (6-27) days. "VS" category patients had significantly prolonged invasive ventilation (median 35 vs. 3 and 1.5 days; p = .008), ICU stay (median 39 vs. 8 and 8 days; p = .007), and hospital stay (64 vs. 26.5 and 23 days; p < .001) when compared to "S" and "M/Mo" groups, respectively. The need for pre-transplant home oxygen therapy was the only factor predicting need for re-intubation. Patient and graft survival at 32 (17-98) months were 100% and 95.8%. All children ultimately had complete resolution of HPS.

CONCLUSIONS

VS HPS is associated with longer duration of mechanical ventilation and hospital stay, which emphasizes the need for early LT in these children.

Obesity Hypoventilation Syndrome-Related Challenges in Acute Respiratory Failure

Obesity hypoventilation syndrome (OHS) is a condition commonly found in severely obese patients in which they fail to breathe deeply or rapidly enough to offset the body's need for oxygen consumption and carbon dioxide release. This report presents a case of a 49-year-old super-super-morbid obese female with a body mass index (BMI) of 90 kilogram per meter squared (kg/m²), chronic obstructive pulmonary disease (COPD), and end-stage cor pulmonale, who was brought to the emergency department for altered mental status and requiring emergent airway due to respiratory failure secondary to OHS. The continued increase in rates of obesity worldwide, especially in those with BMI ≥ 50 kg/m², may lead to an increase in the incidence of OHS. With comorbidities secondary to obesity and associated complexity, this medically challenging case emphasizes the need for refined management strategies in caring for OHS in super-super-morbidly obese patients.

Postoperative Changes in Pulmonary Function after Valve Surgery: Oxygenation Index Early after Cardiopulmonary Is a Predictor of Postoperative Course

Objective: To determine pulmonary functional changes that predict early clinical outcomes in valve surgery requiring long cardiopulmonary bypass (CPB). Methods: This retrospective study included 225 consecutive non-emergency valve surgeries with fast-track cardiac anesthesia between January 2014 and March 2020. Blood gas analyses before and 0, 2, 4, 8, and 14 h after CPB were investigated. Results: Median age and EuroSCORE II were 71.0 years (25–75 percentile: 59.5–77.0) and 2.46 (1.44–5.01). Patients underwent 96 aortic, 106 mitral, and 23 combined valve surgeries. The median CPB time was 151 min (122–193). PaO₂/FiO₂ and AaDO₂/PaO₂ significantly deteriorated two hours, but not immediately, after CPB (both p < 0.0001). Decreased PaO₂/FiO₂ and AaDO₂/PaO₂ were correlated with ventilation time (r² = 0.318 and 0.435) and intensive care unit (ICU) (r² = 0.172 and 0.267) and hospital stays (r² = 0.164 and 0.209). Early and delayed extubations (<6 and >24 h) were predicted by PaO₂/FiO₂ (377.2 and 213.1) and AaDO₂/PaO₂ (0.683 and 1.680), measured two hours after CPB with acceptable sensitivity and specificity (0.700–0.911 and 0.677–0.859). Conclusions: PaO₂/FiO₂ and AaDO₂/PaO₂ two hours after CPB were correlated with ventilation time and lengths of ICU and hospital stays. These parameters suitably predicted early and delayed extubations.

Elective Tracheostomy in Critically Ill Children: A 10-Year Single-Center Experience From a Lower-Middle Income Country

Objective

Tracheostomy is a commonly performed procedure amongst critically ill patients, especially in cases of prolonged mechanical ventilation (PMV). This study aimed to describe the indications, clinical characteristics, and outcomes of elective pediatric tracheostomies in critically ill children at our center.

Methods

A retrospective review of medical records of children who underwent elective tracheostomies in our pediatric intensive care unit (PICU) was conducted from January 2009 to June 2018. Data were extracted based on demographics, indications of tracheostomy, and patient outcomes. Results were reported as mean with standard deviation and as frequencies with percentage.

Results

Of the 3,200 patients admitted to the PICU during the study period, 1,130 were intubated. A total of 48 (4.2% of 1,130) children underwent an elective tracheostomy. 30/48 (62.5%) children had an early tracheostomy. 34/48 (71%) patients were males. Approximately 25% of our patients undergoing a tracheostomy had an underlying neurological condition as the primary diagnosis, followed by respiratory conditions (23%). The most common indications for elective tracheostomy were PMV (>7 days) (n=24, 50%) and extubation failure (n=9, 18.7%). Early tracheostomy (<14 days) had better patient outcomes in terms of ventilator-free days (8.57±4.64 in early tracheostomy vs. 6.38±6.17 days in late tracheostomy, P=0.04). The sedation-free days and ICU-free days were also significantly increased in the early tracheostomy group than in the late tracheostomy group. The successful weaning and ICU discharge rate were significantly higher in the early tracheostomy group than in the late tracheostomy group (78.1% vs. 59.7%, P<0.05; and 69.2% vs. 49.5%, P<0.05, respectively). Ventilator-associated pneumonia was more common in the late tracheostomy group (n= 14, 77%), compared to early tracheostomy group (n=12, 40%) (P=0.03). Two patients expired from tracheostomy-related complications.

Conclusion

PMV was the most common indication for an elective tracheostomy. Early tracheostomy is associated with improved patient outcomes; therefore, a standardized approach toward mechanically ventilated children is recommended.

Predictors of extubation outcomes following myasthenic crisis

Objective Myasthenic crisis (MC) is considered the most severe adverse event in patients with myasthenia gravis. The present retrospective study was performed to evaluate the predictors of clinical outcomes in patients with MC. Methods The medical charts of 33 patients (19 women, 14 men) with 76 MC attacks from 2002 to 2014 were retrospectively reviewed. Early extubation (≤7 days) and prolonged ventilation (>15 days) during the MC were used to assess patient outcomes. Results Among the 33 patients, 24 (72.7%) had positive acetylcholine receptor antibody test results and 20 (60.6%) experienced recurrent MC attacks (≥2 episodes) during follow-up (median 83.6 months, range 1.5-177 months). Plasma exchange during an MC was significantly associated with early extubation. Male sex, older age (>50 years), atelectasis, and ventilator-associated pneumonia significantly contributed to prolonged ventilation. In 22 patients who underwent thymectomy, both the duration between MC attacks and the mean number of MC attacks were significantly reduced after surgery. Conclusions Plasma exchange during MC attacks was found to be important for early extubation; older patients and those with atelectasis or ventilator-associated pneumonia were more vulnerable to prolonged ventilation. Thymectomy may be useful to prevent recurrence of MC.

Evaluation of a Mapleson D CPAP system for weaning of mechanical ventilation in pediatric patients

Background:

Over the last years, we have used a flow-inflating bag circuit with a nasotracheal or nasopharyngeal tube as an interface to deliver effective CPAP support in infants (“Mapleson D CPAP system”). The primary goal of this study was to assess the usefulness of the “Mapleson D CPAP system” for weaning of mechanical ventilation (MV) in infants who received MV over 24 h.

Materials and Methods:

All infants who received MV for more than 24 h in the last year were enrolled in the study. Demographic data included age, gender, weight, and admission diagnosis. Heart rate, respiratory rate, blood pressure, and oxygen saturation were measured during MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation. Patients were classified into two groups: patients MV more than 48 h, and patients with MV fewer than 48 h. P < 0.05 was considered statistically significant.

Results:

A total of 50 children were enrolled in the study, with a median age was 34 ± 45 months (range, 1–59 months) and median weight was 11.98 ± 9.31 kg (range, 1–48 kg). Median duration of MV was 480 h (range, 2–570). There were no significant differences in PaO₂, PaCO₂, and pH among MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation and spontaneous ventilation with the nasopharyngeal Mapleson D CPAP system or with nasal prongs. The overall extubation failure rate was 26% (n = 13). Weight and age were significantly associated with extubation failure (P < 0.05).

Conclusions:

The Mapleson D CPAP system, in our opinion, is a useful and safe alternative to more complex and expensive noninvasive CPAP and BiPAP weaning from MV in infants.

Late tracheotomy is associated with higher morbidity and mortality in mechanically ventilated patients

OBJECTIVES/HYPOTHESIS

To determine whether the timing of tracheotomy placement impacts ventilation weaning status and mortality.

STUDY DESIGN

Multi-institution retrospective cohort study.

METHODS

Demographic data, procedural details, and clinical outcomes were recorded for patients undergoing tracheotomy for prolonged mechanical ventilation across eight sites. The study group was divided into two groups: those undergoing tracheotomy within 14 days of initiation of mechanical ventilation and those undergoing tracheotomy at or after 14 days. Groups were compared for primary outcome measures of mortality and ability to wean from mechanical ventilation within the study period.

RESULTS

Of the 539 patients intubated for ventilator dependence with complete data available, 280 (51.9%) underwent tracheotomy within 14 days. Patients who underwent late tracheotomy were 1.72 times more likely to remain ventilator dependent during the follow-up period (95% confidence interval [CI]: 1.12-2.66), and had a 40% increased risk of death (odds ratio: 1.4, 95% CI: 0.96-1.99).

CONCLUSIONS

In this multicenter retrospective review of tracheotomy outcomes, late tracheotomy placement (>14 days) was associated with increased mortality and prolonged ventilator dependence. Standardized multidisciplinary management protocols for prolonged mechanical ventilation are recommended, and future work should confirm these results in a prospective manner.

LEVEL OF EVIDENCE

4.

Tracheostomy after cardiac surgery: timing of tracheostomy as a risk factor for mortality

OBJECTIVES

The optimal timing for tracheostomy after cardiac surgery in patients undergoing prolonged ventilation is controversial. The aim of this study was to assess the effect of tracheostomy timing on short- and long-term mortality of these patients.

DESIGN

Retrospective study of prospectively collected data.

SETTING

Cardiac surgical intensive care unit (ICU) in a tertiary-care, university-affiliated hospital.

PARTICIPANTS

All patients undergoing tracheostomy after cardiac surgery between September 2004 and March 2013 were included.

INTERVENTIONS

The authors compared the outcome in 2 groups of patients according to the timing of tracheostomy: Group I, early-intermediate tracheostomy (0-14 days) and Group II, late tracheostomy (≥15 days).

MEASUREMENTS AND MAIN RESULTS

During the study period, 6,069 patients underwent cardiac surgery; among them, 199 patients (3.26%) received a tracheostomy. There were 90 patients in Group I and 109 patients in Group II. There was no significant difference in the severity of the patients' illness between the groups. The mortality rate at 3 months, 6 months, 1 year, and 2 years was 37%, 48%, 56%, and 58% in Group I, respectively, and 58%, 70%, 74%, and 77% in Group II, respectively (p< 0.01).

CONCLUSIONS

Early-intermediate (0-14 days) tracheostomy after cardiac surgery in patients requiring prolonged mechanical ventilation was associated with reduced mortality compared with late tracheostomy (≥15 days).

Risk factors of prolonged mechanical ventilation following open heart surgery: what has changed over the last decade?

OBJECTIVE

To identify the risk factors for prolonged invasive mechanical ventilation after open heart surgery in Pakistan.

DESIGN

This study is based on retrospective analysis of database.

PLACE AND DURATION

We conducted study of all patients who underwent open heart surgery at CPE Institute of Cardiology, Multan from March 2009 to May 2011.

PATIENTS & METHODS

The data was retrieved from the database in the form of electronic spreadsheet which was then analyzed using SPSS software. The patients with incomplete data entries were removed from the analysis resulting in a set of 1,617 patients. The data of each patient consisted of 65 preoperative, operative and postoperative variables. The data was summarized as means, medians and standard deviations for numeric variables and frequencies and percentages or categoric variables. These risk factors were compared using Chi-sqaure test. Their ODDs ratios and 95% confidence intervals of ODD's Ratios and P values were calculated.

RESULTS

Out of a total of 1,617 patients, 77 patients (4.76%) had prolonged ventilation for a cumulated duration of more than over 24 hours. Preoperative renal failure, emphysema, low EF (<30%), urgent operation, preoperative critical state, prolonged bypass time, prolonged cross clamp time, complex surgical procedures and peri-operative myocardial infarction were found to be risk factors for PIMV. Old age, female gender, advanced ASA class, advanced NYHA class, diabetes mellitus, smoking, history of COPD, redo surgery, left main stenosis, obesity and use of intra-aortic balloon pump were not found to have significant ODDs ratios for PIMV. The patients with prolonged ventilation had significantly high mortality i.e. 32.47% while the normal ventilation group had 0.32% overall mortality.

CONCLUSIONS

Many of the previously considered risk factors for prolonged ventilation after open heart study are no more significant risk factors. However, prolonged ventilation continues to be associated with very high mortality.