Reading aloud compared with positive expiratory pressure after abdominal surgery. a randomized controlled trial

Background: Without evidence, positive expiratory pressure therapy is a part of rehabilitation worldwide to prevent postoperative hypoxia. Reading aloud could be used as an alternative therapy as lung volumes increases while speaking. We aimed to investigate whether reading aloud is superior to positive expiratory pressure therapy for improving oxygen saturation after abdominal surgery. Material and Methods: This crossover randomized controlled trial compared reading a text aloud with positive expiratory pressure therapy in patients on postoperative day 1 or 2 after upper gastrointestinal, colorectal, urological, or gynecological abdominal surgery at Umeå University Hospital, Sweden. The primary outcome was the change in peripheral oxygen saturation compared with baseline at 7 min after the intervention. The secondary outcome was transcutaneous carbon dioxide partial pressure change. Results: This study included 50 patients of which 48 patients were analyzed. Peripheral oxygen saturation rapidly decreased to minimum values below baseline immediately after both interventions and then increased to values above baseline after reading aloud (1%, 95% confidence interval 0.2% to 1%, P = 0.004), but not after positive expiratory pressure therapy (−0.2%, 95% confidence interval −1% to 0.4%, P = 0.436). The difference in oxygen saturation was 1% (95% confidence interval 0.1% to 2%, P = 0.039) at 7 min after termination of the interventions. The interventions reduced transcutaneous carbon dioxide partial pressure by similar amounts. Conclusions: This trial adds to the evidence against the use of positive expiratory pressure therapy after abdominal surgery. It is even slightly better to read aloud.