Benefits and risks of ventilator hyperinflation in mechanically ventilated intensive care patients: A systematic review and meta-analysis

Patients requiring mechanical ventilation in the intensive care unit (ICU) have diminished respiratory defences and are at high risk of respiratory compromise, leading to an increased risk of pulmonary infection and prolonged ventilation. Ventilator hyperinflation (VHI) is an airway clearance technique used by physiotherapists and is suggested to improve respiratory mechanics. The objective of this study was to review the evidence for the benefits and risks of VHI in intubated and mechanically ventilated patients in the ICU. We conducted a systematic review. We searched PubMed, Embase, CINAHL, CENTRAL, and Scopus from inception to 31st May 2022 for all randomised control trials evaluating VHI in intubated and mechanically ventilated adults in the ICU. Two authors independently performed study selection and data extraction. Individual study risk of bias was assessed using the Physiotherapy Evidence Database scale, and certainty in outcomes was assessed using the Grading of Recommendations, Assessment, Development and Evaluations framework. We included 10 studies enrolling 394 patients. Compared to standard care, VHI had significant effects on sputum clearance (Standardise mean difference: 0.36, 95% confidence interval [CI]: 0.12 to 0.61; very low certainty), static pulmonary compliance (mean difference [MD]: 4.77, 95% CI: 2.40 to 7.14; low certainty), dynamic pulmonary compliance (MD: 1.59, 95% CI: 0.82 to 2.36; low certainty) and oxygenation (MD: 0.28, 95% CI: 0.01 to 0.55; low certainty). No significant adverse events or immediate side effects relating to VHI were reported. There is a paucity of data available on the effects of VHI on clinical outcomes including mechanical ventilation duration, ICU length of stay, and mortality. Our findings suggest VHI has potential short-term respiratory benefits including increased secretion clearance, pulmonary compliance, and oxygenation, with no immediate adverse effects in intubated and mechanically ventilated ICU patients. However, there remains limited data on the longer term influence of VHI on clinical outcomes, and further research to inform clinical practice is needed. This study is registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022341421).