Prediction of postoperative pulmonary complications in a population-based surgical cohort. Anesthesiology. 2010;113:1338-1350. [PMID: 21045639 DOI: 10.1097/aln.0b013e3181fc6e0a]

Anesthesia for esophagectomy

Esophagectomy is a high-risk operation with significant perioperative morbidity and mortality. Attention to detail in many areas of perioperative management should lead to an aggregation of marginal gains and improvement in postoperative outcome. This review addresses preoperative assessment and patient selection, perioperative care (focusing on pulmonary prehabilitation, ventilation strategies, goal-directed fluid therapy, analgesia, and cardiovascular complications), minimally invasive surgery, and current evidence for enhanced recovery in esophagectomy.

[Non-invasive mechanical ventilation in the pre- and intraoperative period and difficult airway]

Non-invasive mechanical ventilation is a method of ventilatory assistance aimed at increasing alveolar ventilation, thus achieving, in selected subjects, the avoidance of endotracheal intubation and invasive mechanical ventilation, with the consequent improvement in survival. There has been a systematic review and study of the technical, clinical experiences, and recommendations concerning the application of non-invasive mechanical ventilation in the pre- and intraoperative period. The use of prophylactic non-invasive mechanical ventilation before surgery that involves significant alterations in the ventilatory function may decrease the incidence of postoperative respiratory complications. Its intraoperative use will mainly depend on the type of surgery, type of anaesthetic technique, and the clinical status of the patient. Its use allows greater anaesthetic depth without deterioration of oxygenation and ventilation of patients.

[Cardiac surgery in underlying chronic pulmonary disease. Prognostic implications and efficient preoperative evaluation]

Cardiac surgery in patients with chronic pulmonary diseases carries a high risk of postoperative pulmonary complications (ppc) because both are known to cause ppc. Autopsy studies have revealed ppc as the main cause of mortality in approximately 5-8% of patients after cardiac surgery. Not all pulmonary diseases are high risk comorbidities in cardiac surgery: whereas chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea significantly increase the risk of ppc, a well controlled asthma does not carry an additional risk of ppc. A thorough preoperative risk stratification is crucial for risk estimation and some validated risk calculators, such as the Canet risk score exist. Surprisingly the additional value of pulmonary function testing beyond a thorough patient history and physical examination is low. No validated thresholds exist in pulmonary function testing below which cardiac surgery should be denied if clearly indicated. Perioperative strategies for risk reduction should be applied to all patients whenever possible.

Low oxygen saturation and mortality in an adult cohort: the Tromsø study

Background

Oxygen saturation has been shown in risk score models to predict mortality in emergency medicine. The aim of this study was to determine whether low oxygen saturation measured by a single-point measurement by pulse oximetry (SpO₂) is associated with increased mortality in the general adult population.

Methods

Pulse oximetry was performed in 5,152 participants in a cross-sectional survey in Tromsø, Norway, in 2001–2002 (“Tromsø 5”). Ten-year follow-up data for all-cause mortality and cause of death were obtained from the National Population and the Cause of Death Registries, respectively. Cause of death was grouped into four categories: cardiovascular disease, cancer except lung cancer, pulmonary disease, and others. SpO₂ categories were assessed as predictors for all-cause mortality and death using Cox proportional-hazards regression models after correcting for age, sex, smoking history, body mass index (BMI), C-reactive protein level, self-reported diseases, respiratory symptoms, and spirometry results.

Results

The mean age was 65.8 years, and 56% were women. During the follow-up, 1,046 (20.3%) participants died. The age- and sex-adjusted hazard ratios (HRs) (95% confidence intervals) for all-cause mortality were 1.99 (1.33–2.96) for SpO₂ ≤ 92% and 1.36 (1.15–1.60) for SpO₂ 93–95%, compared with SpO₂ ≥ 96%. In the multivariable Cox proportional-hazards regression models that included self-reported diseases, respiratory symptoms, smoking history, BMI, and CRP levels as the explanatory variables, SpO₂ remained a significant predictor of all-cause mortality. However, after including forced expiratory volume in 1 s percent predicted (FEV₁% predicted), this association was no longer significant. Mortality caused by pulmonary diseases was significantly associated with SpO₂ even when FEV₁% predicted was included in the model.

Conclusions

Low oxygen saturation was independently associated with increased all-cause mortality and mortality caused by pulmonary diseases. When FEV₁% predicted was included in the analysis, the strength of the association weakened but was still statistically significant for mortality caused by pulmonary diseases.

How slow is too slow? Correlation of operative time to complications: an analysis from the Tennessee Surgical Quality Collaborative

BACKGROUND

The Tennessee Surgical Quality Collaborative analyzes NSQIP data from 21 participating hospitals. The Tennessee Surgical Quality Collaborative has reduced surgical complications, but causative factors are unclear. We sought to correlate surgical duration with complications to reveal mitigating strategies.

STUDY DESIGN

Risk-adjusted Tennessee Surgical Quality Collaborative data on 104,632 general and vascular cases had a standard duration for 35 procedures (eg, breast, colectomy) calculated and NSQIP outcomes complication rates recorded. We derived a marginal time risk for each extra hour of operative time and reported per 1,000 cases.

RESULTS

Procedures taking <95% upper confidence standard time limit (n = 99,741) were deemed "not long" and had significantly fewer urinary tract infections, organ-space surgical site infection, sepsis/septic shock, prolonged intubation, and pneumonia. "Long" cases had increased rates of these complications and also deep venous thrombosis, deep incisional infection, and wound disruption. Per 1,000 cases, there were 116 occurrences per operating room hour. Surgical site infections occurred in 14.4/1,000 cases per hour; risk started at 42 minutes of operative time. Death, pneumonia, and prolonged intubation saw their risks begin before the operation. The highest marginal time risk was for sepsis, occurring 16.6 times per additional hour of operative time over standard. Studying only the 25,146 clean procedures, a significant correlation (p < 0.001) to operation duration persisted, despite an occurrence incidence of 4.5%.

CONCLUSIONS

Duration of operation correlates with complications and time longer than a statewide established standard carries higher risk. To reduce risk of complications, these data support expeditious surgical technique and preoperative pulmonary training, and offer accurate outcomes assessment for patient counseling based on case duration. These data can be used directly to counsel individual surgeons to improve outcomes.

Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD): explanation and elaboration

The TRIPOD (Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis) Statement includes a 22-item checklist, which aims to improve the reporting of studies developing, validating, or updating a prediction model, whether for diagnostic or prognostic purposes. The TRIPOD Statement aims to improve the transparency of the reporting of a prediction model study regardless of the study methods used. This explanation and elaboration document describes the rationale; clarifies the meaning of each item; and discusses why transparent reporting is important, with a view to assessing risk of bias and clinical usefulness of the prediction model. Each checklist item of the TRIPOD Statement is explained in detail and accompanied by published examples of good reporting. The document also provides a valuable reference of issues to consider when designing, conducting, and analyzing prediction model studies. To aid the editorial process and help peer reviewers and, ultimately, readers and systematic reviewers of prediction model studies, it is recommended that authors include a completed checklist in their submission. The TRIPOD checklist can also be downloaded from www.tripod-statement.org.

Predicting postoperative pulmonary complications: implications for outcomes and costs

PURPOSE OF REVIEW

This review of progress toward reliable prediction of postoperative pulmonary complications (PPCs) discusses risk assessment against the background of patient management strategies, clinical outcomes, and cost of healthcare.

RECENT FINDINGS

Among the variety of conditions grouped as PPCs are pneumonia, aspiration pneumonitis, respiratory failure, reintubation within 48 h, weaning failure, pleural effusion, atelectasis, bronchospasm, and pneumothorax. PPC incidence rates range from 2 to 40% depending on context. These events increase mortality, postoperative length of stay, ICU admissions, hospital readmissions, and costs. PPC-associated mortality varies, but can reach as high as 48% in some contexts. ICU admission rates are between 9.5 and 91% higher in patients with PPCs. The mean increase in PPC-related postoperative length of stay is approximately 8 days. The cost of surgery can be two-fold to 12-fold higher when PPCs develop. Strategies proposed to reduce the impact of modifiable risk factors include alcohol and smoking abstinence before surgery, shortening the duration of surgery, and physiotherapy and incentive spirometry techniques; however, little scientific evidence supports them at this time.

SUMMARY

PPCs are associated with a higher incidence of life-threatening events and higher costs. Reliable PPC risk-stratification tools are essential for guiding clinical decision-making in the perioperative period. The care team can act on modifiable factors and optimize vigilance over nonmodifiable ones. It would be useful to focus resources on determining whether low-cost preemptive interventions improve outcomes satisfactorily or new strategies need to be developed.

Early effect of tidal volume on lung injury biomarkers in surgical patients with healthy lungs

BACKGROUND

The early biological impact of short-term mechanical ventilation on healthy lungs is unknown. The authors aimed to characterize the immediate tidal volume (VT)-related changes on lung injury biomarkers in patients with healthy lungs and low risk of pulmonary complications.

METHODS

Twenty-eight healthy patients for knee replacement surgery were prospectively randomized to volume-controlled ventilation with VT 6 (VT6) or 10 (VT10) ml/kg predicted body weight. General anesthesia and other ventilatory parameters (positive end-expiratory pressure, 5 cm H2O, FIO2, 0.5, respiratory rate titrated for normocapnia) were managed similarly in the two groups. Exhaled breath condensate and blood samples were collected for nitrite, nitrate, tumor necrosis factor-α, interleukins-1β, -6, -8, -10, -11, neutrophil elastase, and Clara Cell protein 16 measurements, at the onset of ventilation and 60 min later.

RESULTS

No significant differences in biomarkers were detected between the VT groups at any time. The coefficient of variation of exhaled breath condensate nitrite and nitrate decreased in the VT6 but increased in the VT10 group after 60-min ventilation. Sixty-minute ventilation significantly increased plasma neutrophil elastase levels in the VT6 (35.2 ± 30.4 vs. 56.4 ± 51.7 ng/ml, P = 0.008) and Clara Cell protein 16 levels in the VT10 group (16.4 ± 8.8 vs. 18.7 ± 9.5 ng/ml, P = 0.015). Exhaled breath condensate nitrite correlated with plateau pressure (r = 0.27, P = 0.042) and plasma neutrophil elastase (r = 0.44, P = 0.001). Plasma Clara Cell protein 16 correlated with compliance (r = 0.34, P = 0.014).

CONCLUSIONS

No tidal volume-related changes were observed in the selected lung injury biomarkers of patients with healthy lungs after 60-min ventilation. Plasma neutrophil elastase and plasma Clara Cell protein 16 might indicate atelectrauma and lung distention, respectively.

Predictive Factors Involved in Development of Postoperative Pulmonary Complications

OBJECTIVE

In the present study, we applied the method of the multi-center Prospective Evaluation of a Risk Score for postoperative pulmonary Complications in Europe (PERISCOPE) study, which was designed to predict postoperative complications and funded by the European Society of Anaesthesiology, to patients in our institution with the aim of prospectively analyzing the postoperative risk factors of pulmonary complications.

METHODS

One hundred patients over 18 years of age who had emergency or elective non-thoracic or non-obstetric surgery under general anaesthesia or neuraxial blocks were included in the study. Collected data regarding the preoperative and postoperative period were filled in separate forms for all patients.

RESULTS

A total of 11 patients developed pulmonary complications. We observed respiratory failure in 8 patients, pleural effusion in 3 patients, atelectasis in 5 patients, bronchospasm in 3 patients, and pneumothorax in 1 patient. In the univariate logistic regression model, patient age, gender, weight, rate of preoperative respiratory symptoms, cough test results, American Society of Anesthesiology (ASA) score, and the duration of surgery did not significantly increase the complication risk (p>0.05). However, in the univariate logistic regression model, the presence of respiratory symptoms increased the risk for complications approximately 5.34-fold (p=0.014). There was an increase in the possibility of complications in parallel with the increase in the duration of postoperative hospital stay (p=0.012). More respiratory symptoms (p=0.019) and longer hospital stay (6.5 vs. 3.5 days respectively, p=0.029) were recorded in patients with postoperative pulmonary complications.

CONCLUSION

Considering patients undergoing non-thoracic or non-obstetric surgery, the prevalence of postoperative pulmonary complications is higher in patients diagnosed with respiratory symptoms in the preoperative period. These complications significantly extend the length of hospital stay.

Development of a prediction rule for estimating postoperative pulmonary complications

Patient- and procedure-related factors associated with postoperative pulmonary complications (PPCs) have changed over the last decade. Therefore, we sought to identify independent risk factors of PPCs and to develop a clinically applicable scoring system. We retrospectively analyzed clinical data from 2,059 patients who received preoperative evaluations from respiratory physicians between June 2011 and October 2012. A new scoring system for estimating PPCs was developed using beta coefficients of the final multiple regression models. Of the 2,059 patients studied, 140 (6.8%) had PPCs. A multiple logistic regression model revealed seven independent risk factors (with scores in parentheses): age ≥70 years (2 points), current smoker (1 point), the presence of airflow limitation (1 point), American Society of Anesthesiologists class ≥2 (1 point), serum albumin <4 g/dL (1 point), emergency surgery (2 points), and non-laparoscopic abdominal/cardiac/aortic aneurysm repair surgery (4 points). The area under the curve was 0.79 (95% CI, 0.75–0.83) with the newly developed model. The new risk stratification including laparoscopic surgery has a good discriminative ability for estimating PPCs in our study cohort. Further research is needed to validate this new prediction rule.

Recent advances in mechanical ventilation in patients without acute respiratory distress syndrome

While being an essential part of general anesthesia for surgery and at times even a life-saving intervention in critically ill patients, mechanical ventilation has a strong potential to cause harm. Certain ventilation strategies could prevent, at least to some extent, the injury caused by this intervention. One essential element of so-called ‘lung-protective’ ventilation is the use of lower tidal volumes. It is uncertain whether higher levels of positive end-expiratory pressures have lung-protective properties as well. There are indications that too high oxygen fractions of inspired air, or too high blood oxygen targets, are harmful. Circumstantial evidence further suggests that spontaneous modes of ventilation are to be preferred over controlled ventilation to prevent harm to respiratory muscle. Finally, the use of restrictive sedation strategies in critically ill patients indirectly prevents ventilation-induced injury, as daily spontaneous awakening and breathing trials and bolus instead of continuous sedation are associated with shorter duration of ventilation and shorten the exposure to the injurious effects of ventilation.

Intraoperative positive end-expiratory pressure evaluation using the intratidal compliance-volume profile

BACKGROUND

Lung-protective mechanical ventilation during general surgery including the application of PEEP can reduce postoperative pulmonary complications. In a prospective clinical observation study, we evaluated volume-dependent respiratory system compliance in adult patients undergoing ear-nose-throat surgery with ventilation settings chosen empirically by the attending anaesthetist.

METHODS

In 40 patients, we measured the respiratory variables during intraoperative mechanical ventilation. All measurements were subdivided into 5 min intervals. Dynamic compliance (CRS) and the intratidal volume-dependent CRS curve was calculated for each interval and classified into one of the six specific compliance profiles indicating intratidal recruitment/derecruitment, overdistension or all. We retrospectively compared the occurrences of the respective compliance profiles at PEEP levels of 5 cm H2O and at higher levels.

RESULTS

The attending anaesthetists set the PEEP level initially to 5 cm H2O in 29 patients (83%), to 7 cm H2O in 5 patients (14%), and to 8 cm H2O in 2 patients (6%). Across all measurements the mean CRS was 61 (11) ml cm H2O(-1) (40-86 ml cm H2O(-1)) and decreased continuously during the procedure. At PEEP of 5 cm H2O the compliance profile indicating strong intratidal recruitment/derecruitment occurred more often (18.6%) compared with higher PEEP levels (5.5%, P<0.01). Overdistension was practically never observed.

CONCLUSIONS

In most patients, a PEEP of 5 cm H2O during intraoperative mechanical ventilation is too low to prevent intratidal recruitment/derecruitment. The analysis of the intratidal compliance profile provides the rationale to individually titrate a PEEP level that stabilizes the alveolar recruitment status of the lung during intraoperative mechanical ventilation.

TRIAL REGISTRATION NUMBER

DRKS00004286.

Incidence of mortality and morbidity related to postoperative lung injury in patients who have undergone abdominal or thoracic surgery: a systematic review and meta-analysis

BACKGROUND

Lung injury is a serious complication of surgery. We did a systematic review and meta-analysis to assess whether incidence, morbidity, and in-hospital mortality associated with postoperative lung injury are affected by type of surgery and whether outcomes are dependent on type of ventilation.

METHODS

We searched MEDLINE, CINAHL, Web of Science, and Cochrane Central Register of Controlled Trials for observational studies and randomised controlled trials published up to April, 2014, comparing lung-protective mechanical ventilation with conventional mechanical ventilation during abdominal or thoracic surgery in adults. Individual patients' data were assessed. Attributable mortality was calculated by subtracting the in-hospital mortality of patients without postoperative lung injury from that of patients with postoperative lung injury.

FINDINGS

We identified 12 investigations involving 3365 patients. The total incidence of postoperative lung injury was similar for abdominal and thoracic surgery (3·4% vs 4·3%, p=0·198). Patients who developed postoperative lung injury were older, had higher American Society of Anesthesiology scores and prevalence of sepsis or pneumonia, more frequently had received blood transfusions during surgery, and received ventilation with higher tidal volumes, lower positive end-expiratory pressure levels, or both, than patients who did not. Patients with postoperative lung injury spent longer in intensive care (8·0 [SD 12·4] vs 1·1 [3·7] days, p<0·0001) and hospital (20·9 [18·1] vs 14·7 [14·3] days, p<0·0001) and had higher in-hospital mortality (20·3% vs 1·4% p<0·0001) than those without injury. Overall attributable mortality for postoperative lung injury was 19% (95% CI 18-19), and differed significantly between abdominal and thoracic surgery patients (12·2%, 95% CI 12·0-12·6 vs 26·5%, 26·2-27·0, p=0·0008). The risk of in-hospital mortality was independent of ventilation strategy (adjusted HR 0·71, 95% CI 0·41-1·22).

INTERPRETATION

Postoperative lung injury is associated with increases in in-hospital mortality and durations of stay in intensive care and hospital. Attributable mortality due to postoperative lung injury is higher after thoracic surgery than after abdominal surgery. Lung-protective mechanical ventilation strategies reduce incidence of postoperative lung injury but does not improve mortality.

FUNDING

None.

Cons: endoscopic endonasal transsphenoidal pituitary surgery is not superior to microscopic transsphenoidal surgery for pituitary adenomas

The introduction of the endoscope to transsphenoidal pituitary surgery is not new and it has been abandoned in the past. Now, after some technological advances has been proposed again as an advancement in this field. However, there is still a debate on this topic and some authors consider endoscopic surgery a form of developing surgery in an evolution step. The use of the endoscope to visualize the sella has been suggested to offer a better visualization as well as an improved range of motion compared to the operating microscope. However, the real advantage in terms of efficacy and safety is still matter of debate. The conversion to microsurgery has been reported in a significant number of cases, particularly in recurrences, where the difficulties of reoperation require more skill. There is evidence in recent studies that the endonasal and bleeding complications are significantly higher in endoscopic approaches than in microscopic ones. In particular, patient discomfort, smell, and taste impairment are higher with the endoscopic method compared with microscopic approaches. At present pure endoscopic transsphenoidal surgery is not a cost effective technology. In fact, the operative time is longer than in microscopic approaches and the number of surgeons required for the procedure is usually double compared to microscopic approaches. This paper will outline on the basis of the data available in literature the reasons why, at present, the pure endoscopic endonasal transsphenoidal surgery should not be yet considered the standard technique for transsphenoidal surgery in patients with pituitary adenomas.

Postoperative respiratory failure: pathogenesis, prediction, and prevention

PURPOSE OF REVIEW

This review discusses our present understanding of postoperative respiratory failure (PRF) pathogenesis, risk factors, and perioperative-risk reduction strategies.

RECENT FINDINGS

PRF, the most frequent postoperative pulmonary complication, is defined by impaired blood gas exchange appearing after surgery. PRF leads to longer hospital stays and higher mortality. The time frame for recognizing when respiratory failure is related to the surgical-anesthetic insult remains imprecise, however, and researchers have used different clinical events instead of blood gas measures to define the outcome. Still, studies in specific surgical populations or large patient samples have identified a range of predictors of PRF risk: type of surgery and comorbidity, mechanical ventilation, and multiple hits to the lung have been found to be relevant in most of these studies. Recently, risk-scoring systems for PRF have been developed and are being applied in new controlled trials of PRF-risk reduction measures. Current evidence favors carefully managing intraoperative ventilator use and fluids, reducing surgical aggression, and preventing wound infection and pain.

SUMMARY

PRF is a life-threatening event that is challenging for the surgical team. Risk prediction scales based on large population studies are being developed and validated. We need high-quality trials of preventive measures, particularly those related to ventilator use in both high risk and general populations.

Low FEV1, smoking history, and obesity are factors associated with oxygen saturation decrease in an adult population cohort

Background

Worsening of pulmonary diseases is associated with a decrease in oxygen saturation (SpO₂). Such a decrease in SpO₂ and associated factors has not been previously evaluated in a general adult population.

Aim

We sought to describe SpO₂ in a sample of adults, at baseline and after 6.3 years, to determine whether factors predicting low SpO₂ in a cross-sectional study were also associated with a decrease in SpO₂ in this cohort.

Methods

As part of the Tromsø Study, 2,822 participants were examined with pulse oximetry in Tromsø 5 (2001/2002) and Tromsø 6 (2007/2008). Low SpO₂ by pulse oximetry was defined as an SpO₂ ≤95%, and SpO₂ decrease was defined as a ≥2% decrease from baseline to below 96%.

Results

A total of 139 (4.9%) subjects had a decrease in SpO₂. Forced expiratory volume in 1 second (FEV₁) <50% of the predicted value and current smoking with a history of ≥10 pack-years were the baseline characteristics most strongly associated with an SpO₂ decrease in multivariable logistic regression (odds ratio 3.55 [95% confidence interval (CI) 1.60–7.89] and 2.48 [95% CI 1.48–4.15], respectively). Male sex, age, former smoking with a history of ≥10 pack-years, body mass index ≥30 kg/m², and C-reactive protein ≥5 mg/L were also significantly associated with an SpO₂ decrease. A significant decrease in FEV₁ and a new diagnosis of asthma or chronic obstructive pulmonary disease during the observation period most strongly predicted a fall in SpO₂. A lower SpO₂ decrease was observed in those who quit smoking and those who lost weight, but these tendencies were not statistically significant.

Conclusion

A decrease in SpO₂ was most strongly associated with severe airflow limitation and a history of smoking. Smoking cessation and reducing obesity seem to be important measures to target for avoiding SpO₂ decreases in the general population.

Current ventilation practice during general anaesthesia: a prospective audit in Melbourne, Australia

BACKGROUND

Recent evidence suggests that the use of low tidal volume ventilation with the application of positive end-expiratory pressure (PEEP) may benefit patients at risk of respiratory complications during general anaesthesia. However current Australian practice in this area is unknown.

METHODS

To describe current practice of intraoperative ventilation with regard to tidal volume and application of PEEP, we performed a multicentre audit in patients undergoing general anaesthesia across eight teaching hospitals in Melbourne, Australia.

RESULTS

We obtained information including demographic characteristics, type of surgery, tidal volume and the use of PEEP in a consecutive cohort of 272 patients. The median age was 56 (IQR 42-69) years; 150 (55%) were male. Most common diagnostic groups were general surgery (31%), orthopaedic surgery (20%) and neurosurgery (9.6%). Mean FiO2 was 0.6 (IQR 0.5-0.7). Median tidal volume was 500 ml (IQR 450-550). PEEP was used in 54% of patients with a median value of 5.0 cmH2O (IQR 4.0-5.0) and median tidal volume corrected for predicted body weight was 9.5 ml/kg (IQR 8.5-10.4). Median peak inspiratory pressure was 18 cmH2O (IQR 15-22). In a cohort of patients considered at risk for respiratory complications, the median tidal volume was still 9.8 ml/kg (IQR 8.6-10.7) and PEEP was applied in 66% of patients with a median value of 5 cmH20 (IQR 4-5). On multivariate analyses positive predictors of tidal volume size included male sex (p < 0.01), height (p = 0.04) and weight (p < 0.001). Positive predictors of the use of PEEP included surgery in a tertiary hospital (OR = 3.11; 95% CI: 1.05 to 9.23) and expected prolonged duration of surgery (OR = 2.47; 95% CI: 1.04 to 5.84).

CONCLUSION

In mechanically ventilated patients under general anaesthesia, tidal volume was high and PEEP was applied to the majority of patients, but at modest levels. The findings of our study suggest that the control groups of previous randomized controlled trials do not closely reflect the practice of mechanical ventilation in Australia.

Postoperative pulmonary complications updating

Postoperative pulmonary complications (PPCs) are a major contributor to the overall risk of surgery. PPCs affect the length of hospital stay and are associated with a higher in-hospital mortality. PPCs are even the leading cause of death either in cardiothoracic surgery but also in non-cardiothoracic surgery. Thus, reliable PPCs risk stratification tools are the key issue of clinical decision making in the perioperative period. When the risk is clearly identified related to the patient according the ARISCAT score and/or the type of surgery (mainly thoracic and abdominal), low-cost preemptive interventions improve outcomes and new strategies can be developed to prevent this risk. The EuSOS, PERISCOPE and IMPROVE studies demonstrated this care optimization by risk identification first, then risk stratification and new care (multifaceted) strategies implementation allowing a decrease in PPCs mortality by optimizing the clinical path of the patient and the care resources.

Postoperative outcomes following preoperative inspiratory muscle training in patients undergoing cardiothoracic or upper abdominal surgery: a systematic review and meta analysis

Objective:

To evaluate whether preoperative inspiratory muscle training is effective in preventing postoperative pulmonary complications and reducing length of hospital stay in people undergoing cardiothoracic or upper abdominal surgery.

Data sources:

Medline, CINAHL, AMED, PsychINFO, Scopus, PEDro, and the Cochrane Library.

Review methods:

A systematic review and meta analysis of randomized controlled trials (or quasi-randomized controlled trials) investigating a form of preoperative inspiratory muscle training, compared with sham or no inspiratory muscle training. Participants were adults (16 years and over) awaiting elective open cardiac, thoracic, or upper abdominal surgery. Methodological quality was assessed using the PEDro scale.

Results:

Eight studies involving 295 participants were eligible for inclusion. The trained group had significantly higher maximal inspiratory pressure at the end of the preoperative training period (mean difference: 15 cm H2O, 95% confidence interval (CI): 9 to 21). This benefit was maintained through the early postoperative period, when lung function also recovered significantly more quickly in the trained group. Inspiratory muscle training also substantially reduced postoperative pulmonary complications (relative risk 0.48, 95% CI 0.26 to 0.89). Although not statistically significant, length of hospital stay also tended to favour the trained group. There were no statistically significant differences between the groups for the remaining outcomes. Participant satisfaction with inspiratory muscle training was high.

Conclusion:

Preoperative inspiratory muscle training significantly improves respiratory (muscle) function in the early postoperative period, halving the risk of pulmonary complications. The training does not increase length of stay, but more data are required to confirm whether it reduces length of stay.

Mechanical ventilation in abdominal surgery

One of the key challenges in perioperative care is to reduce postoperative morbidity and mortality. Patients who develop postoperative morbidity but survive to leave hospital have often reduced functional independence and long-term survival. Mechanical ventilation provides a specific example that may help us to shift thinking from treatment to prevention of postoperative complications. Mechanical ventilation in patients undergoing surgery has long been considered only as a modality to ensure gas exchange while allowing maintenance of anesthesia with delivery of inhaled anesthetics. Evidence is accumulating, however, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary function and clinical outcome in patients undergoing abdominal surgery. Non-protective ventilator settings, especially high tidal volume (VT) (>10-12mL/kg) and the use of very low level of positive end-expiratory pressure (PEEP) (PEEP<5cmH2O) or no PEEP, may cause alveolar overdistension and repetitive tidal recruitment leading to ventilator-associated lung injury in patients with healthy lungs. Stimulated by previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung protective mechanical ventilation. In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of mechanical ventilation in patients undergoing abdominal surgery.

High versus low positive end-expiratory pressure during general anaesthesia for open abdominal surgery (PROVHILO trial): a multicentre randomised controlled trial

BACKGROUND

The role of positive end-expiratory pressure in mechanical ventilation during general anaesthesia for surgery remains uncertain. Levels of pressure higher than 0 cm H2O might protect against postoperative pulmonary complications but could also cause intraoperative circulatory depression and lung injury from overdistension. We tested the hypothesis that a high level of positive end-expiratory pressure with recruitment manoeuvres protects against postoperative pulmonary complications in patients at risk of complications who are receiving mechanical ventilation with low tidal volumes during general anaesthesia for open abdominal surgery.

METHODS

In this randomised controlled trial at 30 centres in Europe and North and South America, we recruited 900 patients at risk for postoperative pulmonary complications who were planned for open abdominal surgery under general anaesthesia and ventilation at tidal volumes of 8 mL/kg. We randomly allocated patients to either a high level of positive end-expiratory pressure (12 cm H2O) with recruitment manoeuvres (higher PEEP group) or a low level of pressure (≤2 cm H2O) without recruitment manoeuvres (lower PEEP group). We used a centralised computer-generated randomisation system. Patients and outcome assessors were masked to the intervention. Primary endpoint was a composite of postoperative pulmonary complications by postoperative day 5. Analysis was by intention-to-treat. The study is registered at Controlled-Trials.com, number ISRCTN70332574.

FINDINGS

From February, 2011, to January, 2013, 447 patients were randomly allocated to the higher PEEP group and 453 to the lower PEEP group. Six patients were excluded from the analysis, four because they withdrew consent and two for violation of inclusion criteria. Median levels of positive end-expiratory pressure were 12 cm H2O (IQR 12-12) in the higher PEEP group and 2 cm H2O (0-2) in the lower PEEP group. Postoperative pulmonary complications were reported in 174 (40%) of 445 patients in the higher PEEP group versus 172 (39%) of 449 patients in the lower PEEP group (relative risk 1·01; 95% CI 0·86-1·20; p=0·86). Compared with patients in the lower PEEP group, those in the higher PEEP group developed intraoperative hypotension and needed more vasoactive drugs.

INTERPRETATION

A strategy with a high level of positive end-expiratory pressure and recruitment manoeuvres during open abdominal surgery does not protect against postoperative pulmonary complications. An intraoperative protective ventilation strategy should include a low tidal volume and low positive end-expiratory pressure, without recruitment manoeuvres.

FUNDING

Academic Medical Center (Amsterdam, Netherlands), European Society of Anaesthesiology.

The role of plasma gelsolin in cardiopulmonary bypass induced acute lung injury in infants and young children: a pilot study

BACKGROUND

Acute lung injury (ALI) induced by cardiopulmonary bypass (CPB, CPB-ALI) is a common and serious complication after cardiac surgery. And infants and young children are more prone to CPB-ALI. The purpose of this study was to investigate the perioperative changes of plasma gelsolin (pGSN) in patients below 3 years of age with cardiac surgeries and CPB, and determine whether pGSN are associated with the occurrence and severity of CPB-ALI.

METHODS

Seventy-seven consecutive patients ≤3 years of age with congenital heart diseases (CHD) performed on open heart surgery with CPB were finally enrolled, and assigned to ALI and non-ALI groups according to the American-European Consensus Criteria. Plasma concentrations of gelsolin and total protein were measured at following 8 time points: before CPB (a), after CPB (b), 2 hours after CPB (c), 6 hours after CPB (d), 12 hours after CPB (e), 24 hours after CPB (f), 48 hours after CPB (g) and 72 hours after CPB (h).

RESULTS

Twenty-seven (35.1%) patients developed CPB-ALI in the study, including eleven (14.3%) patients with ARDS. The earliest significant drop of pGSN and normalized pGSN (pGSNN) of ALI group both occurred at 6 hours after CPB (p = 0.04 and p < 0.01), which was much earlier than those of non-ALI group (48 hours, p = 0.03 and 24 hours, p < 0.01); PGSN of ALI group before CPB and 6 hours after CPB were both significantly lower than those of non-ALI group (p < 0.01); PGSNN of ALI group before CPB and 6 hours after CPB were both significantly lower than those of non-ALI group (p < 0.01, p = 0.04); PGSN before CPB was the only independent risk factor predicting the occurrence of CPB-ALI (OR, 1.023; 95% CI, 1.007-1.039; p < 0.01) with an AUC of 0.753 (95% CI, 0.626-0.880); The optimal cutoff value of pGSN before CPB was 264.2 mg/L, with a sensitivity of 58.3% and a specificity 94.7%. And lower pGSN before CPB was significantly associated with the severity of CS-AKI (r = -0.45, p < 0.01).

CONCLUSIONS

Patients developing CPB-ALI had lower plasma gelsolin reservoir and a much more amount and rapid consumption of plasma gelsolin early after operation. PGSN before CPB was an early and sensitive predictor of CPB-ALI in infants and young children undergoing cardiac surgery, and was negatively correlated with the severity of CPB-ALI.

Prospective External Validation of a Predictive Score for Postoperative Pulmonary Complications

Background:

No externally validated risk score for postoperative pulmonary complications (PPCs) is currently available. The authors tested the generalizability of the Assess Respiratory Risk in Surgical Patients in Catalonia risk score for PPCs in a large European cohort (Prospective Evaluation of a RIsk Score for postoperative pulmonary COmPlications in Europe).

Methods:

Sixty-three centers recruited 5,859 surgical patients receiving general, neuraxial, or plexus block anesthesia. The Assess Respiratory Risk in Surgical Patients in Catalonia factors (age, preoperative arterial oxygen saturation in air, acute respiratory infection during the previous month, preoperative anemia, upper abdominal or intrathoracic surgery, surgical duration, and emergency surgery) were recorded, along with PPC occurrence (respiratory infection or failure, bronchospasm, atelectasis, pleural effusion, pneumothorax, or aspiration pneumonitis). Discrimination, calibration, and diagnostic accuracy measures of the Assess Respiratory Risk in Surgical Patients in Catalonia score’s performance were calculated for the Prospective Evaluation of a RIsk Score for postoperative pulmonary COmPlications in Europe cohort and three subsamples: Spain, Western Europe, and Eastern Europe.

Results:

The full Prospective Evaluation of a RIsk Score for postoperative pulmonary COmPlications in Europe data set included 5,099 patients; 725 PPCs were recorded for 404 patients (7.9%). The score’s discrimination was good: c-statistic (95% CI), 0.80 (0.78 to 0.82). Predicted versus observed PPC rates for low, intermediate, and high risk were 0.87 and 3.39% (score &lt;26), 7.82 and 12.98% (≥26 and &lt;45), and 38.13 and 38.01% (≥45), respectively; the positive likelihood ratio for a score of 45 or greater was 7.12 (5.93 to 8.56). The score performed best in the Western Europe subsample—c-statistic, 0.87 (0.83 to 0.90) and positive likelihood ratio, 11.56 (8.63 to 15.47)—and worst in the Eastern Europe subsample. The predicted (5.5%) and observed (5.7%) PPC rates were most similar in the Spain subsample.

Conclusions:

The Assess Respiratory Risk in Surgical Patients in Catalonia score predicts three levels of PPC risk in hospitals outside the development setting. Performance differs between geographic areas.

[Analysis of factors conditioning admission at the critical care unit of surgical patients. Prospective study of 764 patients operated for 1 year at a university and reference hospital]

OBJECTIVE

Assess what factors determine the income of surgical patients in critical care unit after surgery.

MATERIAL AND METHODS

It included a survey of the 10% of all patients operated by the services of General Surgery, Thoracic Surgery, Maxillofacial Surgery, Vascular Surgery, Urology and Otolaryngology during 2012. We performed a prospective, observational study. Pre-, intra-, and post-operative variables were analyzed. Comparisons were made between patients operated under elective and emergency surgery, and between patients admitted in critical care and admitted directly in the ward, using χ(2) of Pearson correlation with a confidence interval of 95%.

RESULTS

Seven hundred and sixty-four patients were included into the study, 304 were admitted in critical care after surgery and 460 were admitted in the ward. The medical history showed a statistically significant association with intensive care unit admission, well as the fact of being labeled with a high risk for the risk scales. Complexity and duration of the surgery showed a statistically significant association with intensive care unit admission, as well as the fact of present intra-operative complications. Emergency surgery was not significantly associated with intensive care unit admission of surgical patients, although these patients had significantly higher numbers of intra- and post-operative complications, and more exitus than those undergoing elective surgery.

CONCLUSIONS

A greater incidence of intensive care unit admission of patients undergoing emergency surgery should significantly reduce morbimortality rate. The existence of specific protocols for intensive care unit admission for urgent surgery, and greater availability of beds could be useful in this regard.

Is postoperative epidural analgesia better than patient-controlled analgesia for radical cystectomy?

Background:

The purpose of this study was to evaluate postoperative epidural analgesia (EPA) and intravenous patient-controlled analgesia (PCA) in terms of morbidity and mortality in patients undergoing radical cystectomy for bladder cancer.

Methods:

A retrospective study on patients undergoing radical cystectomy for clinical Tis-4N0M0 urothelial carcinoma of the bladder was performed. Patients were separated into two groups: primary EPA or PCA for postoperative analgesia. The surgical complication severity was determined according to the Clavien system. Mann-Whitney U tests, χ2 with Yates’ correction, or Fisher’s exact test were used. Predictive risk factors were explored using univariable and multivariable Cox regression models.

Results:

Of the 274 patients studied, 209 (76%) received EPA and 65 (24%) had PCA. Baseline balance was observed. Similar complication rates were observed between the EPA (36%) and PCA (34%) ( p=0.382). Patients greater than 70 years of age had more complications (35% vs 21%, p=0.002). PCA patients had higher rates of high-grade complications compared with EPA patients [40% vs 20% ( p=0.0007)]. Only age at time of surgery ( p=0.032) was associated with complications. Patients with pulmonary disease had a higher risk of complications ( p=0.001). EPA or PCA were not predictors for overall survival.

Conclusions:

There does not appear to be a significant difference in terms of morbidity or mortality between EPA and PCA following radical cystectomy (RC). Rare, catastrophic complications specific to EPA may occur. Standardized reporting of surgical complications is essential to compare studies and appropriately counsel patients.

Monitoring respiration: what the clinician needs to know

A recent large prospective cohort study showed an unexpectedly high in-hospital mortality after major non-cardiac surgery in Europe, as well as a high incidence of postoperative pulmonary complications. The direct effect of postoperative respiratory complications on mortality is still under investigation, for intensive care unit (ICU) and in the perioperative period. Although respiratory monitoring has not been actually proven to affect in-hospital mortality, it plays an important role in patient care, leading to appropriate setting of ventilatory support as well as risk stratification. The aim of this article is to provide an overview of various respiratory monitoring techniques including the role of conventional and most recent methods in the perioperative period and in critically ill patients. The most recent techniques proposed for bedside respiratory monitoring, including lung imaging, are presented and discussed, comparing them to those actually considered as gold standards.

Low intraoperative tidal volume ventilation with minimal PEEP is associated with increased mortality

Background

Anaesthetists have traditionally ventilated patients’ lungs with tidal volumes (TVs) between 10 and 15 ml kg⁻¹ of ideal body weight (IBW), without the use of PEEP. Over the past decade, influenced by the results of the Acute Respiratory Distress Syndrome Network trial, many anaesthetists have begun using lower TVs during surgery. It is unclear whether the benefits of low TV ventilation can be extended into the perioperative period.

Methods

We reviewed the records of 29 343 patients who underwent general anaesthesia with mechanical ventilation between January 1, 2008 and December 31, 2011. We calculated TV kg⁻¹ IBW, PEEP, peak inspiratory pressure (PIP), and dynamic compliance. Cox regression analysis with propensity score matching was performed to examine the association between TV and 30-day mortality.

Results

Median TV was 8.6 [7.7–9.6] ml kg⁻¹ IBW with minimal PEEP [4.0 (2.2–5.0) cm H₂O]. A significant reduction in TV occurred over the study period, from 9 ml kg⁻¹ IBW in 2008 to 8.3 ml kg⁻¹ IBW in 2011 (P=0.01). Low TV 6–8 ml kg⁻¹ IBW was associated with a significant increase in 30-day mortality vs TV 8–10 ml kg⁻¹ IBW: hazard ratio (HR) 1.6 [95% confidence interval (CI) [1.25–2.08], P=0.0002]. The association remained significant after matching: HR 1.63 [95% CI (1.22–2.18), P<0.001]. There was only a weak correlation between TV kg⁻¹ IBW and dynamic compliance (r=−0.006, P=0.31) and a weak-to-moderate correlation between TV kg⁻¹ IBW and PIP (r=0.32 P<0.0001).

Conclusions

Use of low intraoperative TV with minimal PEEP is associated with an increased risk of 30-day mortality.

Anaesthetic perioperative management of patients with pancreatic cancer

Pancreatic cancer remains a significant and unresolved therapeutic challenge. Currently, the only curative treatment for pancreatic cancer is surgical resection. Pancreatic surgery represents a technically demanding major abdominal procedure that can occasionally lead to a number of pathophysiological alterations resulting in increased morbidity and mortality. Systemic, rather than surgical complications, cause the majority of deaths. Because patients are increasingly referred to surgery with at advanced ages and because pancreatic surgery is extremely complex, anaesthesiologists and surgeons play a crucial role in preoperative evaluations and diagnoses for surgical intervention. The anaesthetist plays a key role in perioperative management and can significantly influence patient outcome. To optimise overall care, patients should be appropriately referred to tertiary centres, where multidisciplinary teams (surgical, medical, radiation oncologists, gastroenterologists, interventional radiologists and anaesthetists) work together and where close cooperation between surgeons and anaesthesiologists promotes the safe performance of major gastrointestinal surgeries with acceptable morbidity and mortality rates. In this review, we sought to provide simple daily recommendations to the clinicians who manage pancreatic surgery patients to make their work easier and suggest a joint approach between surgeons and anaesthesiologists in daily decision making.

The postoperative airway: unique challenges?

PURPOSE OF REVIEW

The review is focused on the challenge of managing airway and ventilation in the intraoperative and postoperative period.

RECENT FINDINGS

In past years, a lot of attention was focused on tracheal intubation in difficult airway, whereas only in recent years extubation time of difficult airway is also covering an important role. Protective ventilation strategies have been studied in acute respiratory distress syndrome and then in general anesthesia, either for thoracic or bariatric surgery, whereas in general abdominal surgery, in healthy lung, few studies are present demonstrating the effective protective role of low tidal volume, lung recruitment maneuvers (LRM) and positive end-expiratory pressure (PEEP). In the early postoperative period, the role of noninvasive ventilation is growing as it reduces postoperative pulmonary complications, postoperative length of stay and costs.

SUMMARY

The combination of planning extubation of predicted and unpredicted difficult airway, both intraoperative low tidal volume and low FiO2 with LRM and PEEP at different points of surgery and postoperative noninvasive ventilation should be considered in patients undergoing surgery to decrease the rate of postoperative pulmonary complications and major fatal complications such as brain damage and death.

Postoperative pulmonary complications after surgery in patients with interstitial lung disease

BACKGROUND

Patients with interstitial lung disease (ILD) have a high incidence of postoperative pulmonary complications (PPCs) after lung resection, but there is little data about these complications in ILD after other types of surgery.

OBJECTIVES

The aim of this study was to examine the characteristics and predictors of PPCs after major surgery in patients with ILD.

METHODS

We included 336 patients with ILD who underwent major surgery between January 2005 and December 2010 at two tertiary hospitals in Korea. All types of surgery that had been performed under general anesthesia were included. Demographic characteristics, preoperative lung function, and operative conditions including anesthesia time and estimated blood loss were compared between patients with and without PPCs.

RESULTS

PPCs occurred in 37 patients (11%). Thirteen patients developed pneumonia, the most common PPC, and 11 had acute exacerbation of ILD. In multivariable analysis, BMI <23 (OR = 2.488, 95% CI: 1.084-5.710, p = 0.031), emergency surgery (OR = 23.992, 95% CI: 2.629-218.949, p = 0.005), lung surgery (OR = 5.090, 95% CI: 1.391-18.628, p = 0.014), and longer anesthesia time (OR = 1.595, 95% CI: 1.143-2.227, p = 0.006) were statistically significant risk factors.

CONCLUSIONS

The incidence of PPCs detected over all surgeries was not as high as that reported for lung surgery alone in ILD patients. Lower BMI, emergency surgery, lung surgery, and longer anesthesia time were risk factors. Operative conditions as well as lung function should be considered in preoperative planning and management for ILD patients undergoing major surgery.

Effectiveness of high dose remifentanil in preventing coughing and laryngospasm in non-paralyzed patients for advanced bronchoscopic procedures

BACKGROUND:

Anesthesia for bronchoscopy presents unique challenges, as constant stimulus due to bronchoscope needs to be obtunded using drugs with a minimal post-procedure residual effect. Remifentanil for maintenance is an ideal choice, but optimal doses are yet to be determined.

MATERIALS AND METHODS:

Bronchoscopic procedures were prospectively evaluated for 4 months studying the frequency of complications and anesthesia techniques. Anesthesia was maintained on remifentanil/propofol infusion avoiding neuromuscular blockers. Laryngeal mask airway was used for the controlled ventilation (with high oxygen concentration) that also served as a conduit for bronchoscope insertions. Anesthesiologists were blinded to the study (avoiding performance bias) and the Pulmonologist was blinded to the anesthesia technique (to document unbiased procedural satisfaction scores). Procedures were divided into 2 groups based on the dose of remifentanil used for maintenance: Group-H (high dose −0.26 to 0.5 μg/kg/min and Group-NH (non-high dose ≤0.25 μg/kg/min).

RESULTS:

Observed 75 procedures were divided into Group-H (42) and Group-NH (33). Number of statistical difference was found in demography, procedural profile, hemodynamic parameters and total phenylephrine used. Chi-square test showed Group-NH had significantly higher frequency of laryngospasm (P = 0.047) and coughing (P = 0.002). The likelihood ratio of patient coughing and developing laryngospasm in Group-NH was found to be 4.56 and 10.97 times respectively. Minimum pulse-oximeter saturation was statistically higher in Group-H (98.80% vs. 96.50% P = 0.009). Pulmonologist satisfaction scores were significantly better in Group-H.

CONCLUSIONS:

High dose of remifentanil infusion is associated with a lower incidence of coughing and laryngospasms during bronchoscopy. Simultaneously, it improves Pulmonologist's satisfaction and procedural conditions.

REGEUR J, GÄTKE MR. Minimal impairment in pulmonary function following laparoscopic surgery

BACKGROUND

Pulmonary function may be impaired in connection with laparoscopic surgery, especially in the head-down body position, but the clinical importance has not been assessed in detail. The aim of this study was to assess pulmonary function after laparoscopic hysterectomy and laparoscopic cholecystectomy. We hypothesised that arterial oxygenation would be more impaired after hysterectomy performed in the head-down position than after cholecystectomy in the head-up position.

METHODS

We included 60 women in this prospective, observational study. The patients underwent elective laparoscopic cholecystectomy in the 20° head-up position or hysterectomy in the 30° head-down position. The primary outcome was the difference between arterial oxygenation (PaO2 ) 2 h postoperatively and the preoperative value. Two hours and 24 h after surgery, pulmonary shunt and ventilation-perfusion mismatch were assessed by use of an automatic lung parameter estimation system.

RESULTS

Two hours after surgery, the mean change from baseline in PaO2 was -0.65 kPa [95% confidence interval (CI) -3.5 to 3.4, P = 0.14] in the hysterectomy group and -0.22 kPa [95% CI -3.4 to 2.0, P = 0.12] in the cholecystectomy group (P = 0.88). Shunt was significantly greater in the cholecystectomy group 24 h after surgery compared to the hysterectomy group [4%, 95% CI 0 to 9 vs. 0%, 95% CI 0 to 7, P = 0.02].

CONCLUSIONS

Minimal impairment in pulmonary gas exchange was found after laparoscopic surgery. Pulmonary shunt was larger after laparoscopic cholecystectomy, but no clinically significant differences in postoperative pulmonary gas exchange or spirometry were found between laparoscopic hysterectomy and laparoscopic cholecystectomy.