Does Prophylactic CPAP After Major Abdominal Surgery prevent morbidity?

CPAP Machine
CPAP Machine
A clinical trial assessed the benefit of administering prophylactic continuous positive airway pressure immediately after major abdominal surgery.

The prophylactic use of continuous positive airway pressure (CPAP) within 4 hours of the conclusion of major abdominal surgery was not associated with a lower incidence of pneumonia, reintubation, or death at 30 days, according to clinical trial results published in The Lancet Respiratory Medicine.

The open-label, randomized, phase 3 PRISM trial, a United Kingdom clinical trial involving 70 hospitals in 6 countries, investigated whether CPAP administered immediately after major abdominal surgery could prevent postoperative morbidity. Patients aged 50 years and older undergoing major open abdominal surgery were randomly assigned in a 1:1 ratio to receive CPAP within 4 hours of the end of surgery or usual postoperative care. A computer-generated minimization algorithm with inbuilt concealment was used to randomly assign the patients to 1 of the 2 groups. The primary study outcome was a composite of pneumonia, endotracheal reintubation, or death within 30 days of randomization, which was evaluated in the intent-to-treat population. All patients who received CPAP had their safety assessed as well.

A total of 4806 patients were enrolled in the study between February 2016 and November 2019. Of these, 4793 individuals were included in the primary analysis, 2396 in the CPAP arm and 2397 in the usual-care arm. Patients were enrolled from the following countries: United Kingdom, Italy, Spain, Norway, South Africa, and Sweden. In the CPAP group, the mean duration of CPAP was 194.2 minutes; the median duration of CPAP was 240 minutes.

Overall, 8.1% (195 of 2396) of patients in the CPAP arm and 8.2% (197 of 2397) of those in the usual-care arm met the composite primary outcome (adjusted odds ratio, 1.01; 95% CI, 0.81-1.24; P =.05). Of the participants in the CPAP group, 3.5% (78 of 2241) experienced an adverse event (AE). The most commonly reported AEs in the CPAP arm included claustrophobia in 3.5% of participants, oronasal dryness in 1.9%, excessive air leak in 1.6%, vomiting in 1.2%, and pain in 1.1%. Two serious AEs were reported in the CPAP arm: significant hearing loss in 1 patient and obstruction of the venous catheter caused by a CPAP hood in another individual.

The investigators concluded that the findings from the current study demonstrate that although the use of CPAP plays an important role in treating respiratory failure following surgery, the routine, widespread utilization of prophylactic postoperative CPAP is not recommended. “This trial substantially increases the quality of the available evidence that anaesthetists, surgeons, and critical care physicians can use to inform their clinical practice,” the study authors noted.

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 


PRISM trial group. Postoperative continuous positive airway pressure to prevent pneumonia, re-intubation, and death after major abdominal surgery (PRISM): a multicentre, open-label, randomised, phase 3 trial. Lancet Respir Med. 2021;9(11):1221-1230. doi:10.1016/S2213-2600(21)00089-8