The use of continuous and bilevel positive airway pressure in the PACU for patients with sleep apnea is a debated topic. While some recommend the technology’s use, others have called its benefits uncertain.
Obstructive sleep apnea (OSA) is a disorder in which a person stops breathing intermittently during sleep. It occurs because upper respiratory muscles relax excessively during sleep and allow upper airway tissues to collapse into and block the airway, thereby causing a cessation in breathing (ie, apnea). The consequent drop in blood oxygen ultimately triggers an arousal, which restores an open airway. On resuming sleep, another episode of OSA can occur.
Because of the muscle-relaxant and respiratory effects of many anesthetics, a person with OSA may be more at risk for respiratory complications after surgery (eg, postoperative apnea, hypoxia, sputum retention, bronchopulmonary infections, and pneumonia).1 The most effective treatment for OSA is continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) treatment, which maintains an open airway by blowing pressurized air through the upper airway. In people with OSA, using CPAP/BiPAP treatment during the postanesthesia period should ideally reduce or prevent respiratory complications. Some recent research indicates CPAP/BiPAP treatment may not affect respiratory complications during the postanesthesia period.
A patient is taken to the postanesthesia care unit (PACU) after undergoing surgery with general anesthesia, regional anesthesia, or local anesthesia. In a PACU, the nursing staff monitors the patient’s vital signs (ie, heart rate, blood pressure, temperature, and respiratory rate); manages postoperative pain, postoperative nausea and vomiting, and postanesthetic shivering; and monitors the patient’s surgical site for potential complications such as excessive bleeding, discharge, swelling, hematoma, and redness. Postsurgical complications that can occur as a person recovers from surgery range from none or minimal to life-threatening (eg, laryngospasm, respiratory arrest, pulmonary edema, collapsed lung). Unless complications occur, most patients stay in a PACU for only a few hours. After recovery, a patient may be returned to a same-day surgery unit before returning home or may be returned to another department of the hospital.
Some research indicates noninvasive ventilatory support (eg, BiPAP, CPAP) in the PACU improves respiration during recovery. For example, Spanish researchers found that short-term BiPAP use (approximately 1 hour) during the postanesthesia period improved the efficiency of gas exchange in the lungs of patients who had undergone lung resection2; Belgian researchers found that using BiPAP or CPAP during the first 24 hours postoperatively significantly reduces pulmonary restrictive syndrome (ie, a condition in which distensibility of the lungs is impaired) that can occur after gastroplasty.3 In addition, German researchers found that CPAP can reduce the risk of acute respiratory distress syndrome after upper abdominal surgery.4
Many people with OSA are not diagnosed with the disorder, which may contribute to their having complications after surgery. However, the prevalence of patients with undiagnosed OSA is unclear. To address this issue, a Johns Hopkins University research team, headed by Tracey Stierer, used a questionnaire to identify patients with possible OSA to determine if there was an association between the patients’ risk of OSA and adverse outcomes.5 During a 2-year period, adult patients 18 years or older filled out a questionnaire that obtained data on age, gender, race, body mass index, presence of sleep disturbance symptoms, frequency of sleep-related symptoms (eg, snoring, witnessed apneas), and cardiovascular problems (eg, history of angina, myocardial infarction, stroke, heart failure, and coronary artery revascularization). The likelihood of their having OSA was calculated, based on their answers. A patient having a score over 70% was considered at high risk for OSA.
The researchers also collected information from the anesthesiologists’ reports and reviewed factors such as the choice of anesthetic technique, changes in the anesthetic plan (ie, need to alter airway management from the original plan because of the inability to adequately ventilate the patient’s lungs), difficulty in endotracheal intubation (eg, multiple attempts at laryngoscopy or an inability to properly visualize anatomic structures), a patient having been prescribed vasoactive medications (ie, drugs that constrict or dilate blood vessels), a patient having received an oral airway or nasal trumpet during conscious sedation, and a patient having undergone unplanned placement of a laryngeal mask airway or endotracheal intubation.
Stierer found that 75% of the patients who had a score of 70% or greater had not been diagnosed with OSA. They also found that patients with an increased risk of OSA tended to be more difficult to intubate; were more frequently intraoperatively prescribed pressors (ie, drugs that increase blood pressure); and had lower postoperative oxygen saturation or needed prolonged supplemental oxygen while in the PACU. Stierer concluded that undiagnosed OSA may be relatively common in patients undergoing surgery and that patients who have a diagnosis of OSA or are at risk of having OSA may require additional anesthetic management.
In 2012, the Society for Ambulatory Anesthesia (SAMBA) in its consensus statement recommended that patients with OSA who are to undergo ambulatory surgery should bring their own positive airway pressure machine with them on the day of surgery, and to use their device for several days postoperatively since risks can potentially last for several days after surgery.6 These recommendations were proposed because reports in the medical literature at that time had added data concerning validated screening tools that identify surgical patients with OSA who are likely to develop postoperative complications, and data concerning perioperative complications in OSA patients after outpatient surgery, laparoscopic bariatric surgery, and upper airway surgery.
To the extent these SAMBA recommendations are beneficial is unclear. In the Stierer study, the researchers found that the need for postoperative ventilatory assistance was not significantly different between patients who were and were not at risk for OSA. However, most patients who had a high risk of OSA in their study had not undergone a sleep study to confirm the diagnosis, and therefore the researchers could not record the impact of the severity of OSA on the factors they assessed. This could have affected their results.
There are some drawbacks of patients bringing their machine to a sleep center:
- One, CPAP devices in a PACU setting should be used only by patients who are arousable, are cooperative, and have intact protective airway reflexes (eg, coughing).
- Two, a personal CPAP machine in a PACU setting would require additional hospital resources such as staff time needed to process and inspect the machine, which could be time-consuming and challenging because of the many varieties of positive airway pressure machines; and a PACU staff may not be familiar with how to use different positive airway pressure machines.
- Three, patients with OSA who are treated with CPAP/ BiPAP have an increased risk for upper airway infections5; in a clinical setting, infections may be even more problematic because of hospital-acquired microbes coming home with patients on their machines after surgery. In addition, other hospital patients and staff may become contaminated by microbes from a patient’s machine.
- Four, depending on the type of surgery (eg, head and neck surgery), a patient with OSA may not be able to use the face mask because of the risk of damaging incision sites.
- Five, some physicians may be reluctant to allow a patient to use CPAP/BiPAP immediately after abdominal surgery (eg, gastric bypass) because of fears that the pressure could inflate the stomach (ie, aerophagia) and counteract the goals of the surgery by causing leakage at surgical sites or damaging sutures. However, some research refutes this fear by demonstrating that CPAP does not cause leakage at stitches or excessive pressure on the stomach pouch in patients recovering after bariatric surgery.1,7
The likelihood of a patient using a CPAP or BiPAP machine may increase as the prevalence of OSA increases with rising rates of obesity, which is a risk factor for OSA. Scientists continue to assess the benefit and drawbacks of CPAP/BiPAP in the PACU. However, PACUs can take some actions to address this issue until more definitive information is known. For example, PACUs may have on hand standardized hospital-based machines that can be used in conjunction with a patient’s own face mask. This could minimize the drawbacks of patients bringing in their own machines while allowing them to be treated and potentially avoid postoperative complications. RT
Regina Patrick, RPSGT, is a contributing writer for RT. For further information, contact [email protected].
- Huerta S, DeShields S, Shpiner R, et al. Safety and efficacy of postoperative continuous positive airway pressure to prevent pulmonary complications after Roux-en-Y gastric bypass. Journal of Gastrointestinal Surgery. 2002;6:354-358.
- Aguilo R, Togores B, Pons S, Rubi M, Barbe F, Agusti AG. Noninvasive ventilatory support after lung resectional surgery. Chest. 1997;112:117-121.
- Joris JL, Sottiaux TM, Chiche JD, Desaive CJ, Lamy ML. Effect of bi-level positive airway pressure (BiPAP) nasal ventilation on the postoperative pulmonary restrictive syndrome in obese patients undergoing gastroplasty. Chest. 1997;111:665-670.
- Schmidt GB, Bombeck CT, Bennett EJ, Kotb KM. Continuous positive airway pressure in the prophylaxis of the adult respiratory distress syndrome (ARDS). Langenbecks Archiv fur Chirurgie. 1975;Suppl:439-442.
- Sanner BM, Fluerenbrock N, Kleiber-Imbeck A, Mueller JB, Zidek W. Effect of continuous positive airway pressure therapy on infectious complications in patients with obstructive sleep apnea syndrome. Respiration. 2001;68:483-487.
- Joshi GP, Ankichetty SP, Gan TJ, et al. Society for Ambulatory Anesthesia consensus statement on preoperative selection of adult patients with obstructive sleep apnea scheduled for ambulatory surgery. Anesthesia and Analgesia. 2012;115:1060-1068.
- Weingarten TN, Kendrick ML, Swain M, et al. Effects of CPAP on gastric pouch pressure after bariatric surgery. Obesity Surgery. 2011;21:1900-1905.