Positive airway pressure (PAP) does not increase the risk of morbidity or mortality and can be safely used to treat obstructive sleep apnoea (OSA) in patients undergoing noncardiac surgery, according to a study presented here at the 2014 Annual Meeting of the Canadian Anesthesiologists’ Society (CAS).
Presentation title: Obstructive Sleep Apnea and 30 Day Postoperative Mortality. Abstract 37354
OSA is common in surgical patients, but reported associations of PAP with postoperative cardiopulmonary complications have created concern about using the treatment during surgery, explained lead author Daniel I. McIsaac, MD, MPH, University of Ottawa, Ottawa, Ontario, on June 17.
“These studies have been limited, and the evidence is not particularly strong,” said Dr. McIsaac.
“Adverse events are rare, and longer-term outcomes, like 30-day all-cause mortality, are unclear. The present study, which…validated pre- and post-PAP morbidity and mortality data, addressed these points.”
Dr. McIsaac and colleagues undertook a retrospective cohort study of 333,344 Ontario residents (≥40 years of age) who underwent major elective noncardiac surgery from 2002 to 2012 (excluding those whose surgery was specifically for OSA). Physician-billing claims data accurately captured the use of a polysomnogram (PSG) as the validated method to detect OSA, use (if any) of PAP devices, demographics, surgery, use of healthcare resources, and deaths.
In all, 324,151 patients did not receive a PSG and were included as the reference group. Of the remaining patients, 7,682 did not receive PAP for OSA (untreated OSA), and 1,511 received PAP (treated OSA).
Breaking down the data by time, postoperatively, revealed no significant differences between the 3 patient groups at days 0 to 3 and days 11 to 30. From postoperative day 4 to 10, those with treated OSA were more apt to die than patients in the other groups, but whether this reflected the therapy or the OSA was unclear.
Other results were more conclusive. Death within 30 days of surgery was comparable in patients with PAP-treated OSA (0.6%) and those untreated for OSA (0.6%) (adjusted odds ratio [aOR] = 1.06; 95% confidence interval [CI], 0.76-1.48), as well as in the reference group (0.9%) (aOR = 1.00; 95% CI, 0.52-1.96).
Use of PAP to treat OSA was associated with increased intensive-care-unit (ICU) admission and mechanical ventilation compared with the reference group (OR = 1.93; 95% CI, 1.63-2.29; and OR = 1.37; 95% CI, 1.04-1.82, respectively) and compared with patients untreated for OSA (OR = 1.25; 95% CI, 1.04-1.51; and OR = 1.37; 95% CI, 1.04-1.82, respectively).
No differences in length of hospital stay were evident between those treated for OSA and the reference group (incidence rate ratio [IRR] = 1.00; 95% CI, 0.99-1.01). Similarly, no differences were observed between these groups for hospital readmission (OR = 1.05; 95% CI, 0.77-1.42) or emergency visits (IRR = 1.00; 95% CI, 0.99-1.01).
“Patients receiving PAP therapy for OSA do not experience increased odds of mortality within 30 days of elective intermediate- to high-risk noncardiac surgery,” stated Dr. McIsaac. “Increased odds of ICU admission and mechanical ventilation were observed but did not result in increased hospital length of stay or postdischarge resource utilisation.”
Whether the more resource-intensive care actually improves patient outcomes remains unclear and will require prospective study, the researchers noted.
“The data show that these patients don’t appear to have a worse outcome, but definitive conclusions are beyond the scope of the study,” Dr. McIsaac concluded.