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 (V T) size was 500 ml, or 7 to 9 ml kg−1 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 V T and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.</p

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p&lt;0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p&lt;0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

Acute abdomen as a consequence of an unusual suicide attempt: intra-abdominal injection of sulfuric acid

Anna Lepore,1 Davide D&rsquo;Antini,1 Pasquale Raimondo,2 Lucia Mirabella,1 Leonardo Pennisi,1 Giuseppe Carrillo,1 Antonella Cotoia,1 Michele Dambrosio,1 Gilda Cinnella1 1Department of Anesthesia and Intensive Care, University of Foggia, Viale Pinto, Foggia, 2Department of Anesthesia and Intensive Care, &ldquo;Santa Maria&rdquo; Hospital, Via De Ferrariis, Bari, Italy Abstract: Caustic ingestion is a common cause of life-threatening upper gastrointestinal tract injuries. It mostly happens in children as accidental exposure, but may occur in adults as a result of suicide attempt. We present a case of an acute abdomen that occurred after a peculiar way of self-administration of sulfuric acid as a suicide attempt in an adult psychiatric male patient, already known for self-harm with caustic agents in the previous years. In a few hours, the patient developed diffuse peritonitis, pneumoperitoneum, and a rapid hemodynamic deterioration, as a consequence of ileum and sigmoid necrosis, requiring an emergency surgery with the application of a damage control strategy. The patient was then transferred to intensive care unit for hemodynamic stabilization, and definitive surgical correction of the abdominal lesions was performed after 3 days with Hartmann procedure. Thirty-nine days after hospital admission, the patient was discharged. In conclusion, to our knowledge, never has been reported in the literature a case of intra-abdominal self-administration of caustic substance causing a rapid evolution of clinical conditions and requiring the application of damage control strategy. Keywords: abdomen, acute, caustics, sulfuric acid, suicide, attempted, peritonitis, laparotomy&nbsp

Physiological effects of the open lung approach during laparoscopic cholecystectomy: focus on driving pressure

BACKGROUND: During laparoscopy, respiratory mechanics and gas exchange are impaired because of pneumoperitoneum and atelectasis formation. We applied an open lung approach (OLA) consisting in lung recruitment followed by a decremental positive-end expiratory pressure (PEEP) trial to identify the level of PEEP corresponding to the highest compliance of the respiratory system (best PEEP). Our hypothesis was that this approach would improve both lung mechanics and oxygenation without hemodynamic impairment. METHODS: We studied twenty patients undergoing laparoscopic cholecystectomy. We continuously recorded respiratory mechanics parameters throughout a decremental PEEP trial in order to identify the best PEEP level. Furthermore, lung and chest wall mechanics, respiratory and transpulmonary driving pressures (ΔP), gas exchange and hemodynamics were recorded at three time-points (a) after pneumoperitoneum induction (TpreOLA); (b) after the application of the OLA (TpostOLA) and (c) at the end of surgery, after abdominal deflation (Tend). RESULTS: The "best PEEP" level was 8.1±1.3 cmH2O (range 6 to 10 cmH2O), corresponding to the highest compliance of the respiratory system (CRS). This "best PEEP" level corresponded with lowest ΔPL. OLA increased the compliance of the lung and of the chest wall, and decreased ΔPRS and ΔPL. PaO2/FiO2 increased from 299±125 mmHg to 406±101 mmHg (p=0.04). Changes in respiratory mechanics, driving pressures and oxygenation were maintained until Tend. Hemodynamic parameters remained stable throughout the study period. CONCLUSIONS: In patients undergoing laparoscopic cholecystectomy, the OLA was suitable for bedside PEEP setting, improved lung mechanics and gas exchange without significant adverse hemodynamic effects

Physiological effects of the open lung approach during laparoscopic cholecystectomy: Focus on driving pressure

BACKGROUND: During laparoscopy, respiratory mechanics and gas exchange are impaired because of pneumoperitoneum and atelectasis formation. We applied an open lung approach (OLA) consisting in lung recruitment followed by a decremental positive-end expiratory pressure (PEEP) trial to identify the level of PEEP corresponding to the highest compliance of the respiratory system (best PEEP). Our hypothesis was that this approach would improve both lung mechanics and oxygenation without hemodynamic impairment. METHODS: We studied twenty patients undergoing laparoscopic cholecystectomy. We continuously recorded respiratory mechanics parameters throughout a decremental PEEP trial in order to identify the best PEEP level. Furthermore, lung and chest wall mechanics, respiratory and transpulmonary driving pressures (?P), gas exchange and hemodynamics were recorded at three time-points: 1) after pneumoperitoneum induction (TpreOLA); 2) after the application of the OLA(TpostOLA); 3) at the end of surgery, after abdominal deflation (Tend). RESULTS: The "best PEEP" level was 8.1±1.3 cmH2O(range 6 to 10 cmH2O), corresponding to the highest compliance of the respiratory system (CRS). This "best PEEP" level corresponded with lowest ?PL. OLAincreased the compliance of the lung and of the chest wall, and decreased ?PRSand ?PL. PaO2/FiO2 increased from 299±125 mmHg to 406±101 mmHg (P=0.04). Changes in respiratory mechanics, driving pressures and oxygenation were maintained until Tend. Hemodynamic parameters remained stable throughout the study period. CONCLUSIONS: In patients undergoing laparoscopic cholecystectomy, the OLAwas suitable for bedside PEEP setting, improved lung mechanics and gas exchange without significant adverse hemodynamic effects

Effects of different levels of variability and pressure support ventilation on lung function in patients with mild-moderate acute respiratory distress syndrome

Background: Variable pressure support ventilation (vPSV) is an assisted ventilation mode that varies the level of pressure support on a breath-by-breath basis to restore the physiological variability of breathing activity. We aimed to compare the effects of vPSV at different levels of variability and pressure support (ΔPS) in patients with acute respiratory distress syndrome (ARDS). Methods: This study was a crossover randomized clinical trial. We included patients with mild to moderate ARDS already ventilated in conventional pressure support ventilation (PSV). The study consisted of two blocks of interventions, and variability during vPSV was set as the coefficient of variation of the ΔPS level. In the first block, the effects of three levels of variability were tested at constant ΔPS: 0% (PSV0%, conventional PSV), 15% (vPSV15%), and 30% (vPSV30%). In the second block, two levels of variability (0% and variability set to achieve ±5 cmH2O variability) were tested at two ΔPS levels (baseline ΔPS and ΔPS reduced by 5 cmH2O from baseline). The following four ventilation strategies were tested in the second block: PSV with baseline ΔPS and 0% variability (PSVBL) or ±5 cmH2O variability (vPSVBL), PSV with ΔPS reduced by 5 cmH2O and 0% variability (PSV−5) or ±5 cmH2O variability (vPSV−5). Outcomes included gas exchange, respiratory mechanics, and patient-ventilator asynchronies. Results: The study enrolled 20 patients. In the first block of interventions, oxygenation and respiratory mechanics parameters did not differ between vPSV15% and vPSV30% compared with PSV0%. The variability of tidal volume (VT) was higher with vPSV15% and vPSV30% compared with PSV0%. The incidence of asynchronies and the variability of transpulmonary pressure (PL) were higher with vPSV30% compared with PSV0%. In the second block of interventions, different levels of pressure support with and without variability did not change oxygenation. The variability of VT and PL was higher with vPSV−5 compared with PSV−5, but not with vPSVBL compared with PSVBL. Conclusion: In patients with mild-moderate ARDS, the addition of variability did not improve oxygenation at different pressure support levels. Moreover, high variability levels were associated with worse patient-ventilator synchrony. Clinical Trial Registration: www.clinicaltrials.gov, identifier: NCT01683669

The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients - a posthoc propensity score-weighted cohort analysis of the LAS VEGAS study

BackgroundIt is uncertain whether the association of the intraoperative driving pressure (Delta P) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time-weighted average Delta P (Delta P-TW) with PPCs. We also tested the association of Delta P-TW with intraoperative adverse events.MethodsPosthoc retrospective propensity score-weighted cohort analysis of patients undergoing open or closed abdominal surgery in the 'Local ASsessment of Ventilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study, that included patients in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs. The secondary endpoint was a composite of intraoperative adverse events.ResultsThe analysis included 1128 and 906 patients undergoing open or closed abdominal surgery, respectively. The PPC rate was 5%. Delta P was lower in open abdominal surgery patients, but Delta P-TW was not different between groups. The association of Delta P-TW with PPCs was significant in both groups and had a higher risk ratio in closed compared to open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P &lt; 0.001 versus 1.05 [95%CI 1.05 to 1.05], P &lt; 0.001; risk difference 0.05 [95%CI 0.04 to 0.06], P &lt; 0.001). The association of &lt;Delta&gt;P-TW with intraoperative adverse events was also significant in both groups but had higher odds ratio in closed compared to open abdominal surgery patients (1.13 [95%CI 1.12- to 1.14], P &lt; 0.001 versus 1.07 [95%CI 1.05 to 1.10], P &lt; 0.001; risk difference 0.05 [95%CI 0.030.07], P &lt; 0.001).Conclusions&lt;Delta&gt;P is associated with PPC and intraoperative adverse events in abdominal surgery, both in open and closed abdominal surgery.Trial registrationLAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223)

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

Summary 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 computergenerated 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