ESA Clinical Trials Network 2012: LAS VEGAS--Local Assessment of Ventilatory Management during General Anaesthesia for Surgery and its effects on Postoperative Pulmonary Complications: a prospective, observational, international, multicentre cohort study

Association of preoperative smoking with the occurrence of postoperative pulmonary complications: A post hoc analysis of an observational study in 29 countries

INTRODUCTION

While smoking has been consistently identified as a significant contributor to postoperative complications, the existing literature on its association with postoperative pulmonary complications remains conflicting.

AIM

We examined the association of preoperative smoking with the occurrence of postoperative pulmonary complications (PPCs).

METHODS

Post hoc analysis of an observational study in 146 hospitals across 29 countries. We included patients at increased risk of PPCs, according to the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score (≥ 26 points). The primary endpoint was the occurrence of one or more predefined PPCs in the first five postoperative days, including unplanned postoperative need for supplementary oxygen, respiratory failure, unplanned need for invasive ventilation, ARDS, pneumonia and pneumothorax. Secondary endpoints included length of hospital stay and in-hospital mortality. We performed propensity score matching to correct for factors with a known association with postoperative outcomes.

RESULTS

Out of 2632 patients, 531 (20.2 %) patients were smokers and 2102 (79.8 %) non-smokers. At five days after surgery, 101 (19.0 %) smokers versus 404 (19.2) non-smokers had developed one or more PPCs (P = 0.95). Respiratory failure was more common in smokers (5.1 %) than non-smokers (3.0 %) (P = 0.02), while rates of other PPCs like need for supplementary oxygen, invasive ventilation, ARDS, pneumonia, or pneumothorax did not differ between the groups. Length of hospital stay and mortality was not different between groups. Propensity score matching did not change the findings.

CONCLUSION

The occurrence of PPCs in smokers is not different from non-smokers.

FUNDING

This analysis was performed without additional funding. LAS VEGAS was partially funded and endorsed by the European Society of Anaesthesiology through their Clinical Trial Network and the Amsterdam University Medical Centers, Amsterdam, The Netherlands.

REGISTRATION

LAS VEGAS was registered at Clinicaltrials.gov (NCT01601223).

PRIOR PRESENTATION

Preliminary study results have been presented at the Euroanaesthesia 2024 International Congress, in Munich, Germany.

Sex dependence of postoperative pulmonary complications - A post hoc unmatched and matched analysis of LAS VEGAS

STUDY OBJECTIVE

Male sex has inconsistently been associated with the development of postoperative pulmonary complications (PPCs). These studies were different in size, design, population and preoperative risk. We reanalysed the database of 'Local ASsessment of Ventilatory management during General Anaesthesia for Surgery study' (LAS VEGAS) to evaluate differences between females and males with respect to PPCs.

DESIGN, SETTING AND PATIENTS

Post hoc unmatched and matched analysis of LAS VEGAS, an international observational study in patients undergoing intraoperative ventilation under general anaesthesia for surgery in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs in the first 5 postoperative days. Individual PPCs, hospital length of stay and mortality were secondary endpoints. Propensity score matching was used to create a similar cohort regarding type of surgery and epidemiological factors with a known association with development of PPCs.

MAIN RESULTS

The unmatched cohort consisted of 9697 patients; 5342 (55.1%) females and 4355 (44.9%) males. The matched cohort consisted of 6154 patients; 3077 (50.0%) females and 3077 (50.0%) males. The incidence in PPCs was neither significant between females and males in the unmatched cohort (10.0 vs 10.7%; odds ratio (OR) 0.93 [0.81-1.06]; P = 0.255), nor in the matched cohort (10.5 vs 10.0%; OR 1.05 [0.89-1.25]; P = 0.556). New invasive ventilation occurred less often in females in the unmatched cohort. Hospital length of stay and mortality were similar between females and males in both cohorts.

CONCLUSIONS

In this conveniently-sized worldwide cohort of patients receiving intraoperative ventilation under general anaesthesia for surgery, the PPC incidence was not significantly different between sexes.

REGISTRATION

LAS VEGAS was registered at clinicaltrial.gov (study identifier NCT01601223).

Geo-economic variations in epidemiology, ventilation management and outcome of patients receiving intraoperative ventilation during general anesthesia- posthoc analysis of an observational study in 29 countries

BACKGROUND

The aim of this analysis is to determine geo-economic variations in epidemiology, ventilator settings and outcome in patients receiving general anesthesia for surgery.

METHODS

Posthoc analysis of a worldwide study in 29 countries. Lower and upper middle-income countries (LMIC and UMIC), and high-income countries (HIC) were compared. The coprimary endpoint was the risk for and incidence of postoperative pulmonary complications (PPC); secondary endpoints were intraoperative ventilator settings, intraoperative complications, hospital stay and mortality.

RESULTS

Of 9864 patients, 4% originated from LMIC, 11% from UMIC and 85% from HIC. The ARISCAT score was 17.5 [15.0-26.0] in LMIC, 16.0 [3.0-27.0] in UMIC and 15.0 [3.0-26.0] in HIC (P = .003). The incidence of PPC was 9.0% in LMIC, 3.2% in UMIC and 2.5% in HIC (P < .001). Median tidal volume in ml kg^- 1 predicted bodyweight (PBW) was 8.6 [7.7-9.7] in LMIC, 8.4 [7.6-9.5] in UMIC and 8.1 [7.2-9.1] in HIC (P < .001). Median positive end-expiratory pressure in cmH₂O was 3.3 [2.0-5.0]) in LMIC, 4.0 [3.0-5.0] in UMIC and 5.0 [3.0-5.0] in HIC (P < .001). Median driving pressure in cmH₂O was 14.0 [11.5-18.0] in LMIC, 13.5 [11.0-16.0] in UMIC and 12.0 [10.0-15.0] in HIC (P < .001). Median fraction of inspired oxygen in % was 75 [50-80] in LMIC, 50 [50-63] in UMIC and 53 [45-70] in HIC (P < .001). Intraoperative complications occurred in 25.9% in LMIC, in 18.7% in UMIC and in 37.1% in HIC (P < .001). Hospital mortality was 0.0% in LMIC, 1.3% in UMIC and 0.6% in HIC (P = .009).

CONCLUSION

The risk for and incidence of PPC is higher in LMIC than in UMIC and HIC. Ventilation management could be improved in LMIC and UMIC.

TRIAL REGISTRATION

Clinicaltrials.gov , identifier: NCT01601223.

Epidemiology, ventilation management and outcome in patients receiving intensive care after non-thoracic surgery - Insights from the LAS VEGAS study

INTRODUCTION AND OBJECTIVES

Information about epidemiology, ventilation management and outcome in postoperative intensive care unit (ICU) patients remains scarce. The objective was to test whether postoperative ventilation differs from that in the operation room.

MATERIAL AND METHODS

This was a substudy of the worldwide observational LAS VEGAS study, including patients undergoing non-thoracic surgeries. Of 146 study sites participating in the LAS VEGAS study, 117 (80%) sites reported on the postoperative ICU course, including ventilation and complications. The coprimary outcomes were two key elements of ventilator management, i.e., tidal volume (V_T) and positive end-expiratory pressure (PEEP). Secondary outcomes included the proportion of patients receiving low V_T ventilation (LTVV, defined as ventilation with a median V_T < 8.0 ml/kg PBW), and the proportion of patients developing postoperative pulmonary complications (PPC), including ARDS, pneumothorax, pneumonia and need for escalation of ventilatory support, ICU and hospital length of stay, and mortality at day 28.

RESULTS

Of 653 patients who were admitted to the ICU after surgery, 274 (42%) patients received invasive postoperative ventilation. Median postoperative V_T was 8.4 [7.3-9.8] ml/kg predicted body weight (PBW), PEEP was 5 [5-5] cm H₂O, statistically significant but not meaningfully different from median intraoperative V_T (8.1 [7.3-8.9] ml/kg PBW; P < 0.001) and PEEP (4 [2-5] cm H₂O; P < 0.001). The proportion of patients receiving LTVV after surgery was 41%. The PPC rate was 10%. Length of stay in ICU and hospital was independent of development of a PPC, but hospital mortality was higher in patients who developed a PPC (24 versus 4%; P < 0.001).

CONCLUSIONS

In this observational study of patients undergoing non-thoracic surgeries, postoperative ventilation was not meaningfully different from that in the operating room. Like in the operating room, there is room for improved use of LTVV. Development of PPC is associated with mortality.

Intraoperative mechanical ventilation practice in thoracic surgery patients and its association with postoperative pulmonary complications: results of a multicenter prospective observational study

Background

Intraoperative mechanical ventilation may influence postoperative pulmonary complications (PPCs). Current practice during thoracic surgery is not well described.

Methods

This is a post-hoc analysis of the prospective multicenter cross-sectional LAS VEGAS study focusing on patients who underwent thoracic surgery. Consecutive adult patients receiving invasive ventilation during general anesthesia were included in a one-week period in 2013. Baseline characteristics, intraoperative and postoperative data were registered. PPCs were collected as composite endpoint until the 5th postoperative day. Patients were stratified into groups based on the use of one lung ventilation (OLV) or two lung ventilation (TLV), endoscopic vs. non-endoscopic approach and ARISCAT score risk for PPCs. Differences between subgroups were compared using χ² or Fisher exact tests or Student’s t-test. Kaplan–Meier estimates of the cumulative probability of development of PPC and hospital discharge were performed. Cox-proportional hazard models without adjustment for covariates were used to assess the effect of the subgroups on outcome.

Results

From 10,520 patients enrolled in the LAS VEGAS study, 302 patients underwent thoracic procedures and were analyzed. There were no differences in patient characteristics between OLV vs. TLV, or endoscopic vs. open surgery. Patients received V_T of 7.4 ± 1.6 mL/kg, a PEEP of 3.5 ± 2.4 cmH₂O, and driving pressure of 14.4 ± 4.6 cmH₂O. Compared with TLV, patients receiving OLV had lower V_T and higher peak, plateau and driving pressures, higher PEEP and respiratory rate, and received more recruitment maneuvers. There was no difference in the incidence of PPCs in OLV vs. TLV or in endoscopic vs. open procedures. Patients at high risk had a higher incidence of PPCs compared with patients at low risk (48.1% vs. 28.9%; hazard ratio, 1.95; 95% CI 1.05–3.61; p = 0.033). There was no difference in the incidence of severe PPCs. The in-hospital length of stay (LOS) was longer in patients who developed PPCs. Patients undergoing OLV, endoscopic procedures and at low risk for PPC had shorter LOS.

Conclusion

PPCs occurred frequently and prolonged hospital LOS following thoracic surgery. Proportionally large tidal volumes and high driving pressure were commonly used in this sub-population. However, large RCTs are needed to confirm these findings.

Trial registration

This trial was prospectively registered at the Clinical Trial Register (www.clinicaltrials.gov; NCT01601223; registered May 17, 2012.)

The LAS VEGAS risk score for prediction of postoperative pulmonary complications: An observational study

BACKGROUND

Currently used pre-operative prediction scores for postoperative pulmonary complications (PPCs) use patient data and expected surgery characteristics exclusively. However, intra-operative events are also associated with the development of PPCs.

OBJECTIVE

We aimed to develop a new prediction score for PPCs that uses both pre-operative and intra-operative data.

DESIGN

This is a secondary analysis of the LAS VEGAS study, a large international, multicentre, prospective study.

SETTINGS

A total of 146 hospitals across 29 countries.

PATIENTS

Adult patients requiring intra-operative ventilation during general anaesthesia for surgery.

INTERVENTIONS

The cohort was randomly divided into a development subsample to construct a predictive model, and a subsample for validation.

MAIN OUTCOME MEASURES

Prediction performance of developed models for PPCs.

RESULTS

Of the 6063 patients analysed, 10.9% developed at least one PPC. Regression modelling identified 13 independent risk factors for PPCs: six patient characteristics [higher age, higher American Society of Anesthesiology (ASA) physical score, pre-operative anaemia, pre-operative lower SpO2 and a history of active cancer or obstructive sleep apnoea], two procedure-related features (urgent or emergency surgery and surgery lasting ≥ 1 h), and five intra-operative events [use of an airway other than a supraglottic device, the use of intravenous anaesthetic agents along with volatile agents (balanced anaesthesia), intra-operative desaturation, higher levels of positive end-expiratory pressures > 3 cmH2O and use of vasopressors]. The area under the receiver operating characteristic curve of the LAS VEGAS risk score for prediction of PPCs was 0.78 [95% confidence interval (95% CI), 0.76 to 0.80] for the development subsample and 0.72 (95% CI, 0.69 to 0.76) for the validation subsample.

CONCLUSION

The LAS VEGAS risk score including 13 peri-operative characteristics has a moderate discriminative ability for prediction of PPCs. External validation is needed before use in clinical practice.

TRIAL REGISTRATION

The study was registered at Clinicaltrials.gov, number NCT01601223.

Application of Positive End-Expiratory Pressure (PEEP) in Patients During Prolonged Gynecological Surgery

Introduction: A lot of clinical studies have shown that during prolonged surgery protective ventilation strategy, including low tidal volume, PEEP and recruitment maneuvers (RM) can reduce the rate of postoperative pulmonary complications, which are the second most common cause for postoperative mortality. Therefore, it is important to investigate clinical methods for preventing them. The strategy of protective ventilation is easy and safe for the patients and inexpensive for application during prolonged surgery.

Aims: The objective of this trial was to study whether application of PEEP in patients during prolonged gynecological surgery could decrease the postoperative complications.

Material and Methods: We compared the rates of postoperative complications in patients after prolonged open gynecological surgery, who were divided into 2 groups – group A, which was the control group on non-protective ventilation (35 patients) and group B on protective ventilation (35 patients). The patients in the control group were ventilated with tidal volume (VT) of 8-10 ml/kg without PEEP and RM; the patients in group B were ventilated with VT = 6-8 ml/kg according to their Predicted Body Weight, with a PEEP of 6 cm H2O and RM, which consisted of applying continuous positive airway pressure of 30 cm H2O for 30 seconds. RM was performed after intubation, after every disconnection from ventilator and before extubation. The study was successfully performed without a need for a change in the type of ventilation strategy because of hypoxia or hemodynamic instability. Statistical nonparametric test (e.g. chi-square) was applied.

Results: Total rate of all postoperative complications observed in both groups was 27,1%. We found a significant relationship between application of PEEP and lower rates of postoperative pulmonary complications in group A (39,4%) compared to group B (12,1%), lower rate of respiratory failure (33,3% in group A vs. 9,1% in group B -) and atelectasis (21,2% in group A vs. 0% in group B).

Conclusion: The protective ventilation strategy (low VT, PEEP and RM) in patients during prolonged gynecological surgery can reduce the rate of postoperative pulmonary complications such as respiratory failure and atelectasis.

RELAx - REstricted versus Liberal positive end-expiratory pressure in patients without ARDS: protocol for a randomized controlled trial

BACKGROUND

Evidence for benefit of high positive end-expiratory pressure (PEEP) is largely lacking for invasively ventilated, critically ill patients with uninjured lungs. We hypothesize that ventilation with low PEEP is noninferior to ventilation with high PEEP with regard to the number of ventilator-free days and being alive at day 28 in this population.  METHODS/DESIGN: The "REstricted versus Liberal positive end-expiratory pressure in patients without ARDS" trial (RELAx) is a national, multicenter, randomized controlled, noninferiority trial in adult intensive care unit (ICU) patients with uninjured lungs who are expected not to be extubated within 24 h. RELAx will run in 13 ICUs in the Netherlands to enroll 980 patients under invasive ventilation. In all patients, low tidal volumes are used. Patients assigned to ventilation with low PEEP will receive the lowest possible PEEP between 0 and 5 cm H2O, while patients assigned to ventilation with high PEEP will receive PEEP of 8 cm H2O. The primary endpoint is the number of ventilator-free days and being alive at day 28, a composite endpoint for liberation from the ventilator and mortality until day 28, with a noninferiority margin for a difference between groups of 0.5 days. Secondary endpoints are length of stay (LOS), mortality, and occurrence of pulmonary complications, including severe hypoxemia, major atelectasis, need for rescue therapies, pneumonia, pneumothorax, and development of acute respiratory distress syndrome (ARDS). Hemodynamic support and sedation needs will be collected and compared.

DISCUSSION

RELAx will be the first sufficiently sized randomized controlled trial in invasively ventilated, critically ill patients with uninjured lungs using a clinically relevant and objective endpoint to determine whether invasive, low-tidal-volume ventilation with low PEEP is noninferior to ventilation with high PEEP.

TRIAL REGISTRATION

ClinicalTrials.gov , ID: NCT03167580 . Registered on 23 May 2017.

Current research priorities in perioperative intensive care medicine

INTRODUCTION

Surgical treatments are offered to more patients than ever before, and increasingly to older patients with chronic disease. High-risk patients frequently require critical care either in the immediate postoperative period or after developing complications. The purpose of this review was to identify and prioritise themes for future research in perioperative intensive care medicine.

METHODS

We undertook a priority setting process (PSP). A panel was convened, drawn from experts representing a wide geographical area, plus a patient representative. The panel was asked to suggest and prioritise key uncertainties and future research questions in the field of perioperative intensive care through a modified Delphi process. Clinical trial registries were searched for on-going research. A proposed "Population, Intervention, Comparator, Outcome" (PICO) structure for each question was provided.

RESULTS

Ten key uncertainties and future areas of research were identified as priorities and ranked. Appropriate intravenous fluid and blood component therapy, use of critical care resources, prevention of delirium and respiratory management featured prominently.

CONCLUSION

Admissions following surgery contribute a substantial proportion of critical care workload. Studies aimed at improving care in this group could have a large impact on patient-centred outcomes and optimum use of healthcare resources. In particular, the optimum use of critical care resources in this group is an area that requires urgent research.

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - an observational study in 29 countries

BACKGROUND

Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients.

OBJECTIVES

To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs.

DESIGN

This was a prospective international 1-week observational study using the 'Assess Respiratory Risk in Surgical Patients in Catalonia risk score' (ARISCAT score) for PPC for risk stratification.

PATIENTS AND SETTING

Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes.

RESULTS

A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure.

CONCLUSION

The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.

TRIAL REGISTRATION

The study was registered at Clinicaltrials.gov, number NCT01601223.

Preventing Ventilator-Associated Lung Injury: A Perioperative Perspective

Introduction

Research into the prevention of ventilator-associated lung injury (VALI) in patients with acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) has resulted in the development of a number of lung protective strategies, which have become commonplace in the treatment of critically ill patients. An increasing number of studies have applied lung protective ventilation in the operating room to otherwise healthy individuals. We review the history of lung protective strategies in patients with acute respiratory failure and explore their use in patients undergoing mechanical ventilation during general anesthesia. We aim to provide context for a discussion of the benefits and drawbacks of lung protective ventilation, as well as to inform future areas of research.

Methods

We completed a database search and reviewed articles investigating lung protective ventilation in both the ICU and in patients receiving general anesthesia through May 2015.

Results

Lung protective ventilation was associated with improved outcomes in patients with acute respiratory failure in the ICU. Clinical evidence is less clear regarding lung protective ventilation for patients undergoing surgery.

Conclusion

Lung protective ventilation strategies, including low tidal volume ventilation and moderate positive end-expiratory pressure, are well established therapies to minimize lung injury in critically ill patients with and without lung disease, and may provide benefit to patients undergoing general anesthesia.