CPAP Compliance Improves Outcomes

For many, complying with CPAP at home can be a chore. When you add a post-surgical hospital stay, a treatment that may have been just annoying at home becomes downright impossible.

Cumbersome though it may be, perioperative continuous positive airway pressure (CPAP) is a boon to obstructive sleep apnea (OSA) patients undergoing surgery, according to a meta-analysis. Researchers from Toronto Western Hospital found that CPAP reduces the perioperative Apnea-Hypopnea Index (AHI) and hospital length of stay (LOS) in this at-risk patient population.

Though it’s logical that CPAP would offer benefits after surgery, Mahesh Nagappa, MD, DNB, MNAMS, a fellow at Toronto Western, said there’s not enough patient education in the pre-operative period.

“Many patients use CPAP irregularly at home,” he acknowledged. “In the hospital, many experience post-operative nausea, pain or anxiousness and don’t want to add CPAP to that. Others who’ve had surgery involving the nose or oral cavities can’t do CPAP.”

Shockingly Low Post-OP CPAP Compliance

When used correctly, CPAP can significantly shorten recovery. Since that rarely happens in the hospital setting, complications frequently follow the surgery.

“We already know that the prevalence of obstructive sleep apnea in the general population is very high,” said Nagappa. “The prevalence is not only higher in the surgical population than in the general population, but most OSA patients who come for surgery may be undiagnosed, untreated and have many coexisting diseases. All of these may lead to increased perioperative adverse events.”

The most common complication is desaturation, noted Nagappa. However, re-intubation, failed extubation, hypertension and other cardiovascular issues are on the typical trajectory for many patients after surgery.

“People had a tendency to stay in the post-op area for observation for a long time,” he commented. “The stay in the PACU would increase. When they use CPAP, the general hospital length of stay decreases because they can use opiates more liberally and go home sooner.”

SEE ALSO Sleeping Easy During Home Studies

This study evaluated whether the administration of CPAP during the perioperative period, and its effect on the length of hospital stay and the Apnea-Hypopnea Index.

Nagappa and his colleagues performed an English-language literature search for OSA studies of adult surgical patients who were either using or not using perioperative CPAP, with reported data on AHI and hospital LOS. A total of five manuscripts were analyzed.

As Nagappa reported at the 2014 annual meeting of the American Society of Anesthesiologists, two studies provided data on preoperative (n=100) and postoperative (n=51) AHI in patients treated with CPAP. These studies revealed that CPAP significantly reduced the perioperative API. Indeed, the preoperative index of 37±19 events per hour fell to 12±16 events per hour (P<0.001).

“So we saw a decrease of about 25 events per hour when using CPAP,” Nagappa confirmed. “It’s important to remember that 12 events every hour is still on the high side, so the CPAP was not completely effective in resolving sleep-breathing disorders.”

Three studies provided data on hospital LOS, revealing that CPAP patients (n=264) had a significantly shorter stay than their counterparts who did not receive CPAP (3.9±4.0 vs. 4.3±4 days; P>0.05). A shorter length of stay directly translates to greater health care financial savings, both to the system and the patient.

“We also examined the data regarding the continued use of CPAP in these patients,” Nagappa said. “Among the studies, preoperative CPAP was as used by 278 patients, but only 117 patients used it in the postoperative period. So the compliance rate was very poor, only 42%.

Even Nagappa admits the compliance rate was much lower than he expected. Still, he’s optimistic that the reality could improve with more clinician awareness and, subsequently, better patient education.

“So the two important messages I want to convey is we really need to educate our patients as well as other health care professionals regarding the importance of using CPAP in the preoperative and postoperative period,” he said. “

Groundwork for Future Studies
Nagappa and his team hope to use this study as a springing base for more involved research on CPAP in the post-operative environment. For one, his study did not differentiate between the type of surgery performed or the duration of the operation. Hospitals use different reporting criteria so it’s difficult to gauge without a larger study.

He also noted that this study, as with many others focusing on CPAP compliance, was retroactive. “This is not something that can be studied in a randomized clinical trial,” he concluded. “If that was attempted, patients would have to enroll in the CPAP or no CPAP group. If they’re enrolled in the no CPAP group, they’ll have questions and may even drop out of the study. Everybody knows that using CPAP will improve outcomes.”

Robin Hocevar is on staff at ADVANCE. Contact

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