Efficacy of continuous positive airway pressure and incentive spirometry on respiratory functions during the postoperative period following supratentorial craniotomy: A prospective randomized controlled study

Abstract

Study objective: Volume controlled ventilation with low PEEP is used in neuro-anesthesia to provide constant PaCO₂ levels and prevent raised intracranial pressure. Therefore, neurosurgery patients prone to atelectasis formation, however, we could not find any study that evaluates prevention of postoperative pulmonary complications in neurosurgery.

Design: A prospective, randomized controlled study.

Setting: Intensive care unit in a university hospital in Istanbul.

Patients: Seventy-nine ASAI-II patients aged between 18 and 70years scheduled for elective supratentorial craniotomy were included in the study.

Interventions: Patients randomized into 3 groups after surgery. The Group IS (n=20) was treated with incentive spirometry 5 times in 1min and 5min per hour, the Group CPAP (n=20) with continuous positive airway pressure 10 cmH₂O pressure and 0.4 F_iO₂ via an oronasal mask 5min per hour, and the Group Control (n=20) 4L·min^-1O₂ via mask; all during the first 6h postoperatively. Respiratory functions tests and arterial blood gases analysis were performed before the induction of anesthesia (Baseline), 30min, 6h, 24h postoperatively.

Main results: The IS and CPAP applications have similar effects with respect to FVC values. The postoperative 30min FEV₁ values were statistically significantly reduced compared to the Baseline in all groups (p<0.0001). FEV₁ values were statistically significantly increased at the postoperative 24h compared to the postoperative 30min in the Groups IS and CPAP (p<0.0001). This increase, however, was not observed in the Group Control, and the postoperative 24h FEV₁ values were statistically significantly lower in the Group Control compared to the Group IS (p=0.015).

Conclusion: Although this study is underpowered to detect differences in FEV₁ values, the postoperative 24h FEV₁ values were significantly higher in the IS group than the Control group and this difference was not observed between the CPAP and Control groups. It might be evaluate a favorable effect of IS in neurosurgery patients. But larger studies are needed to make a certain conclusion.

Keywords: Continuous positive airway pressure; Craniotomy; Incentive spirometry; Postoperative pulmonary complications; Pulmonary function tests.