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.

Effect of Intraoperative Ventilation Strategies on Postoperative Pulmonary Complications: A Meta-Analysis

Introduction: The role of intraoperative ventilation strategies in subjects undergoing surgery is still contested. This meta-analysis study was performed to assess the relationship between the low tidal volumes strategy and conventional mechanical ventilation in subjects undergoing surgery.Methods: A systematic literature search up to December 2020 was performed in OVID, Embase, Cochrane Library, PubMed, and Google scholar, and 28 studies including 11,846 subjects undergoing surgery at baseline and reporting a total of 2,638 receiving the low tidal volumes strategy and 3,632 receiving conventional mechanical ventilation, were found recording relationships between low tidal volumes strategy and conventional mechanical ventilation in subjects undergoing surgery. Odds ratio (OR) or mean difference (MD) with 95% confidence intervals (CIs) were calculated between the low tidal volumes strategy vs. conventional mechanical ventilation using dichotomous and continuous methods with a random or fixed-effect model.Results: The low tidal volumes strategy during surgery was significantly related to a lower rate of postoperative pulmonary complications (OR, 0.60; 95% CI, 0.44–0.83, p &lt; 0.001), aspiration pneumonitis (OR, 0.63; 95% CI, 0.46–0.86, p &lt; 0.001), and pleural effusion (OR, 0.72; 95% CI, 0.56–0.92, p &lt; 0.001) compared to conventional mechanical ventilation. However, the low tidal volumes strategy during surgery was not significantly correlated with length of hospital stay (MD, −0.48; 95% CI, −0.99–0.02, p = 0.06), short-term mortality (OR, 0.88; 95% CI, 0.70–1.10, p = 0.25), atelectasis (OR, 0.76; 95% CI, 0.57–1.01, p = 0.06), acute respiratory distress (OR, 1.06; 95% CI, 0.67–1.66, p = 0.81), pneumothorax (OR, 1.37; 95% CI, 0.88–2.15, p = 0.17), pulmonary edema (OR, 0.70; 95% CI, 0.38–1.26, p = 0.23), and pulmonary embolism (OR, 0.65; 95% CI, 0.26–1.60, p = 0.35) compared to conventional mechanical ventilation.Conclusions: The low tidal volumes strategy during surgery may have an independent relationship with lower postoperative pulmonary complications, aspiration pneumonitis, and pleural effusion compared to conventional mechanical ventilation. This relationship encouraged us to recommend the low tidal volumes strategy during surgery to avoid any possible complications.

Protective ventilation measures improve outcomes during major vascular surgery

Background: In major endovascular and open vascular surgery cases, pulmonary complications remain persistently high and the most prevalent. Despite strong evidence from intensive care unit (ICU) practices demonstrating benefits of ventilation management with low tidal volume and high positive end expiratory pressure (PEEP), no consensus exists regarding protective ventilation use intraoperatively. Methods: A single institute, patient and surgeon blinded, prospective, randomized study design was used. Patients undergoing major vascular surgery (vascular surgery scheduled for >120 minutes and requiring general anesthesia) from 2015-2016 were randomized to pre-defined control (n = 14) or intervention (n =19) intraoperative ventilation arms. As described later, intervention consisted of a combination of low tidal volume, optimized positive end expiratory pressure (PEEP) and low intraoperative FiO2. Primary outcomes included all-cause mortality, myocardial infarction (MI) and reintubation within 7 post-operative days (POD). Secondary outcomes included atelectasis, pulmonary function measures, hospital length of stay and post-operative complications of re-intubation, pneumonia, sespsis, unplanned readmission or return to operating room, and/or mortality. Results: The intervention arm had significantly reduced post-operative atelectasis ((p <0.02) and increased post-operative SpO2 (p< 0.02). The intervention arm also had a significantly lower length of hospital stay (6.9±5.5 vs 3.3±1.8, p < 0.016). This was corroborated by a multivariate regression analysis that showed therapy was independently correlated with decreased length of stay (p<0.007). Conclusion: Our data indicate a combination of low tidal volumes, optimized PEEP and low FiO2 improves outcomes of patients undergoing major vascular surgery. Importantly, our study demonstrates that these study parameters for evaluation of intraoperative ventilation management are feasible in a busy academic center and a larger clinical trial is worthy. Protective intraoperative ventilation measures could have significant effects on vascular surgery outcomes.

Anesthesia management in neonatal congenital bronchobiliary fistula: case report and literature review

Background There is very little published literature and none that discussed care in a neonate regarding anesthetic risk and management of neonate with congenital bronchobiliary fistula during thoracoscopy and thoracotomy. This article analyzes related risk factors and literature review from perioperative ventilation, circulation and other aspects of management. Case presentation A neonate diagnosed as congenital bronchobiliary fistula combined with severe chemical pneumonia, consolidation of the lungs, and infection was facing the risk of anaesthesia under thoracoscopy exploration surgery, who experiened more than 20 days diagnostic period before operation. Many risk factors have led to conversion from minimally invasive surgery to thoracotomy, including persistent hypoxemia, hypercapnia, difficult surgical exposure and extremly difficulty of intraoperative ventilation management. Anesthesia maintenance after conversion to open access remained problematic. Fortunately the patient showed no sign of any adverse CNS effects after 4 months of follow-up. Conclusions The most prominent anesthesia challenges are hypoxemia, increased airway resistance, impaired ventilation, and the risk of metabolic acidosis. Close cooperation among the entire neonatal medical team is the key factors in successful management of this rare case.