Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis

Abstract

Objective: To identify, appraise, and synthesise the best available evidence on the efficacy of perioperative interventions to reduce postoperative pulmonary complications (PPCs) in adult patients undergoing non-cardiac surgery.

Design: Systematic review and meta-analysis of randomised controlled trials.

Data sources: Medline, Embase, CINHAL, and CENTRAL from January 1990 to December 2017.

Eligibility criteria: Randomised controlled trials investigating short term, protocolised medical interventions conducted before, during, or after non-cardiac surgery were included. Trials with clinical diagnostic criteria for PPC outcomes were included. Studies of surgical technique or physiological or biochemical outcomes were excluded.

Data extraction and synthesis: Reviewers independently identified studies, extracted data, and assessed the quality of evidence. Meta-analyses were conducted to calculate risk ratios with 95% confidence intervals. Quality of evidence was summarised in accordance with GRADE methods. The primary outcome was the incidence of PPCs. Secondary outcomes were respiratory infection, atelectasis, length of hospital stay, and mortality. Trial sequential analysis was used to investigate the reliability and conclusiveness of available evidence. Adverse effects of interventions were not measured or compared.

Results: 117 trials enrolled 21 940 participants, investigating 11 categories of intervention. 95 randomised controlled trials enrolling 18 062 participants were included in meta-analysis; 22 trials were excluded from meta-analysis because the interventions were not sufficiently similar to be pooled. No high quality evidence was found for interventions to reduce the primary outcome (incidence of PPCs). Seven interventions had low or moderate quality evidence with confidence intervals indicating a probable reduction in PPCs: enhanced recovery pathways (risk ratio 0.35, 95% confidence interval 0.21 to 0.58), prophylactic mucolytics (0.40, 0.23 to 0.67), postoperative continuous positive airway pressure ventilation (0.49, 0.24 to 0.99), lung protective intraoperative ventilation (0.52, 0.30 to 0.88), prophylactic respiratory physiotherapy (0.55, 0.32 to 0.93), epidural analgesia (0.77, 0.65 to 0.92), and goal directed haemodynamic therapy (0.87, 0.77 to 0.98). Moderate quality evidence showed no benefit for incentive spirometry in preventing PPCs. Trial sequential analysis adjustment confidently supported a relative risk reduction of 25% in PPCs for prophylactic respiratory physiotherapy, epidural analgesia, enhanced recovery pathways, and goal directed haemodynamic therapies. Insufficient data were available to support or refute equivalent relative risk reductions for other interventions.

Conclusions: Predominantly low quality evidence favours multiple perioperative PPC reduction strategies. Clinicians may choose to reassess their perioperative care pathways, but the results indicate that new trials with a low risk of bias are needed to obtain conclusive evidence of efficacy for many of these interventions.

Study registration: Prospero CRD42016035662.

Fig 1

Screening and selection of studies for systematic review and meta-analysis of postoperative pulmonary complication (PPC) outcomes. CPAP=continuous positive airway pressure; ERAS=enhanced recovery after surgery; FiO₂=fractional inspiration oxygen; HFNC=high flow nasal cannula; NIV=non-invasive ventilation; PEEP=positive end expiratory pressure

Fig 2

Risk of bias graph showing each risk of bias item as percentages across all included studies

Fig 3

Forest plot of strategies for efficacy in reducing risk of postoperative pulmonary complications (PPCs). Strategies were tested with standard medical care as control. CPAP=continuous positive airway pressure; ERAS=enhanced recovery after surgery; FiO₂=fractional inspiration oxygen; HFNC=high flow nasal cannula; n=number of patients with PPC outcome in each group; N=total number of patients in each group; NIV=non-invasive ventilation

Fig 4

Forest plot of strategies for efficacy in reducing risk of respiratory infection. Strategies were tested with standard medical care as control. CPAP=continuous positive airway pressure; ERAS=enhanced recovery after surgery; HFNC=high flow nasal cannula; n=number of patients with respiratory infection outcome in each group; N=total number of patients in each group

Fig 5

Forest plot of strategies for efficacy of reducing risk of atelectasis. Strategies were tested with standard medical care as control. CPAP=continuous positive airway pressure; ERAS=enhanced recovery after surgery; n=number of patients with atelectasis outcome in each group; N=total number of patients in each group

Fig 6

Forest plot of hospital length of stay for strategies investigated to reduce postoperative pulmonary complications. Strategies were tested with standard medical care as a control. CPAP=continuous positive airway pressure; ERAS=enhanced recovery after surgery; NIV=non-invasive ventilation

Fig 7

Forest plot of mortality for strategies investigated to reduce postoperative pulmonary complications. Strategies were tested with standard medical care as control. CPAP=continuous positive airway pressure; ERAS=enhanced recovery after surgery; n=number of patients with mortality outcome in each group; N=total number of patients in each group; NIV=non-invasive ventilation