Intraoperative respiratory and hemodynamic strategies for reducing nausea, vomiting, and pain after surgery: Systematic review and meta-analysis.

BACKGROUND: Despite improved medical treatment strategies, postoperative pain, nausea, and vomiting remain major challenges. This systematic review investigated the relationship between perioperative respiratory and hemodynamic interventions and postoperative pain, nausea, and vomiting. METHODS: PubMed and Embase were searched on March 8, 2021 for randomized clinical trials investigating the effect of perioperative respiratory or hemodynamic interventions in adults undergoing non-cardiac surgery. Investigators reviewed trials for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed when feasible. GRADE was used to assess the certainty of the evidence. RESULTS: This review included 65 original trials; of these 48% had pain, nausea, and/or vomiting as the primary focus. No reduction of postoperative pain was found in meta-analyses when comparing recruitment maneuvers with no recruitment, high (80%) to low (30%) fraction of oxygen, low (5-7 ml/kg) to high (9-12 ml/kg) tidal volume, or goal-directed hemodynamic therapy to standard care. In the meta-analysis comparing recruitment maneuvers with no recruitment maneuvers, patients undergoing laparoscopic gynecological surgery had less shoulder pain 24 h postoperatively (mean difference in the numeric rating scale from 0 to 10: -1.1, 95% CI: -1.7, -0.5). In meta-analyses, comparing high to low fraction of inspired oxygen and goal-directed hemodynamic therapy to standard care in patients undergoing abdominal surgery, the risk of postoperative nausea and vomiting was reduced (odds ratio: 0.45, 95% CI: 0.24, 0.87 and 0.48, 95% CI: 0.27, 0.85). The certainty in the evidence was mostly very low to low. The results should be considered exploratory given the lack of prespecified hypotheses and corresponding risk of Type 1 errors. CONCLUSION: There is limited evidence regarding the impact of intraoperative respiratory and hemodynamic interventions on postoperative pain or nausea and vomiting. More definitive trials are needed to guide clinical care within this area.

Fraction of inspired oxygen during general anesthesia for non-cardiac surgery: Systematic review and meta-analysis.

BACKGROUND: Controversy exists regarding the effects of a high versus a low intraoperative fraction of inspired oxygen (FiO2 ) in adults undergoing general anesthesia. This systematic review and meta-analysis investigated the effect of a high versus a low FiO2 on postoperative outcomes. METHODS: PubMed and Embase were searched on March 22, 2022 for randomized clinical trials investigating the effect of different FiO2 levels in adults undergoing general anesthesia for non-cardiac surgery. Two investigators independently reviewed studies for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed for relevant outcomes, and potential effect measure modification was assessed in subgroup analyses and meta-regression. The evidence certainty was evaluated using GRADE. RESULTS: This review included 25 original trials investigating the effect of a high (mostly 80%) versus a low (mostly 30%) FiO2 . Risk of bias was intermediate for all trials. A high FiO2 did not result in a significant reduction in surgical site infections (OR: 0.91, 95% CI 0.81-1.02 [p = .10]). No effect was found for all other included outcomes, including mortality (OR = 1.27, 95% CI: 0.90-1.79 [p = .18]) and hospital length of stay (mean difference = 0.03 days, 95% CI -0.25 to 0.30 [p = .84). Results from subgroup analyses and meta-regression did not identify any clear effect modifiers across outcomes. The certainty of evidence (GRADE) was rated as low for most outcomes. CONCLUSIONS: In adults undergoing general anesthesia for non-cardiac surgery, a high FiO2 did not improve outcomes including surgical site infections, length of stay, or mortality. However, the certainty of the evidence was assessed as low.

Ventilation Strategies During General Anesthesia for Noncardiac Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: The optimal ventilation strategy during general anesthesia is unclear. This systematic review investigated the relationship between ventilation targets or strategies (eg, positive end-expiratory pressure [PEEP], tidal volume, and recruitment maneuvers) and postoperative outcomes. METHODS: PubMed and Embase were searched on March 8, 2021, for randomized trials investigating the effect of different respiratory targets or strategies on adults undergoing noncardiac surgery. Two investigators reviewed trials for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed for relevant outcomes, and several subgroup analyses were conducted. The certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: This review included 63 trials with 65 comparisons. Risk of bias was intermediate for all trials. In the meta-analyses, lung-protective ventilation (ie, low tidal volume with PEEP) reduced the risk of combined pulmonary complications (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.28-0.49; 9 trials; 1106 patients), atelectasis (OR, 0.39; 95% CI, 0.25-0.60; 8 trials; 895 patients), and need for postoperative mechanical ventilation (OR, 0.36; 95% CI, 0.13-1.00; 5 trials; 636 patients). Recruitment maneuvers reduced the risk of atelectasis (OR, 0.44; 95% CI, 0.21-0.92; 5 trials; 328 patients). We found no clear effect of tidal volume, higher versus lower PEEP, or recruitment maneuvers on postoperative pulmonary complications when evaluated individually. For all comparisons across targets, no effect was found on mortality or hospital length of stay. No effect measure modifiers were found in subgroup analyses. The certainty of evidence was rated as very low, low, or moderate depending on the intervention and outcome. CONCLUSIONS: Although lung-protective ventilation results in a decrease in pulmonary complications, randomized clinical trials provide only limited evidence to guide specific ventilation strategies during general anesthesia for adults undergoing noncardiac surgery.

Goal-directed haemodynamic therapy during general anaesthesia for noncardiac surgery: a systematic review and meta-analysis.

BACKGROUND: During general anaesthesia for noncardiac surgery, there remain knowledge gaps regarding the effect of goal-directed haemodynamic therapy on patient-centred outcomes. METHODS: Included clinical trials investigated goal-directed haemodynamic therapy during general anaesthesia in adults undergoing noncardiac surgery and reported at least one patient-centred postoperative outcome. PubMed and Embase were searched for relevant articles on March 8, 2021. Two investigators performed abstract screening, full-text review, data extraction, and bias assessment. The primary outcomes were mortality and hospital length of stay, whereas 15 postoperative complications were included based on availability. From a main pool of comparable trials, meta-analyses were performed on trials with homogenous outcome definitions. Certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). RESULTS: The main pool consisted of 76 trials with intermediate risk of bias for most outcomes. Overall, goal-directed haemodynamic therapy might reduce mortality (odds ratio=0.84; 95% confidence interval [CI], 0.64 to 1.09) and shorten length of stay (mean difference=-0.72 days; 95% CI, -1.10 to -0.35) but with low certainty in the evidence. For both outcomes, larger effects favouring goal-directed haemodynamic therapy were seen in abdominal surgery, very high-risk surgery, and using targets based on preload variation by the respiratory cycle. However, formal tests for subgroup differences were not statistically significant. Goal-directed haemodynamic therapy decreased risk of several postoperative outcomes, but only infectious outcomes and anastomotic leakage reached moderate certainty of evidence. CONCLUSIONS: Goal-directed haemodynamic therapy during general anaesthesia might decrease mortality, hospital length of stay, and several postoperative complications. Only infectious postoperative complications and anastomotic leakage reached moderate certainty in the evidence.

Factors associated with shockable versus non-shockable rhythms in patients with in-hospital cardiac arrest.

AIM: To identify factors associated with the initial rhythm in patients with in-hospital cardiac arrest and to assess whether potential differences in outcomes based on the initial rhythm can be explained by patient and event characteristics. METHODS: Adult patients (≥18 years old) with in-hospital cardiac arrest in 2017 and 2018 were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST). We used population-based registries to obtain data on comorbidities, cardiac procedures, and medications. Unadjusted and adjusted risk ratios (RRs) for initial rhythm, return of spontaneous circulation (ROSC), and survival were estimated in separate models including an incremental number of prespecified variables. RESULTS: A total of 3422 patients with in-hospital cardiac arrest were included, of which 639 (19%) had an initial shockable rhythm. Monitored cardiac arrest, witnessed cardiac arrest, and specific cardiac diseases (i.e. ischemic heart disease, dysrhythmias, and valvular heart disease) were associated with initial shockable rhythm. Conversely, higher age, female sex, and specific non-cardiovascular comorbidities (e.g. overweight and obesity, renal disease, and pulmonary cancer) were associated with an initial non-shockable rhythm. Initial shockable rhythm remained strongly associated with increased ROSC (RR = 1.63, 95%CI 1.51-1.76), 30-day survival (RR = 2.31, 95%CI 2.02-2.64), and 1-year survival (RR = 2.36, 95%CI 2.02-2.76) compared to initial non-shockable rhythm in the adjusted analyses. CONCLUSION: In this study, specific patient and cardiac arrest characteristics were associated with initial rhythm in patients with in-hospital cardiac arrest. However, differences in patient and cardiac arrest characteristics did not fully explain the association with survival for initial shockable rhythm compared to a non-shockable rhythm.