Sleep Apnea Study Seeks to Identify Patients at Risk for Surgical Complications
A research team from the Jefferson Sleep Disorders Center at Thomas Jefferson University Hospital has utilized a simple, eight-item, pre-operative questionnaire about obstructive sleep apnea syndrome that could help identify patients at risk for complications following surgery, according to a report in the October issue of Archives of Otolaryngology - Head & Neck Surgery, one of the JAMA/Archives journals. Individuals prone to the obstructive sleep apnea syndrome as determined by the questionnaire appear to have an increased risk of heart, lung and other complications following elective surgery.
Obstructive sleep apnea syndrome, a disorder in which individuals periodically stop breathing during sleep, occurs in approximately two percent to four percent of the general population. The condition may be more common among patients undergoing surgery, and the related cardiorespiratory consequences may be exacerbated following surgical procedures because anesthetic agents and pain relievers decrease muscle tone in the upper airways and diminish control of breathing.
"Based on this knowledge, it is important to identify surgical patients who are at high risk for obstructive sleep apnea syndrome," said Tajender S. Vasu, M.D., the study's lead author, and Fellow in Sleep Medicine at the Jefferson Sleep Disorders Center of Thomas Jefferson University.
Polysomnography conducted in a sleep laboratory and home sleep testing have both been used to diagnose obstructive sleep apnea. However, neither procedure has been used extensively among patients preparing for surgery. The research team studied 135 patients undergoing elective surgery in May 2008. Before their procedures, all the patients completed the STOP-BANG (Snoring, Tiredness during daytime, Observed apnea, high blood Pressure, Body mass index, Age, Neck circumference and Gender) questionnaire, which consists of eight yes-or-no questions to assess apnea.
Of the patients, 56 (41.5 percent) had high scores on STOP-BANG, indicating a high risk for obstructive sleep apnea and 12 (8.9 percent) experienced heart or lung-related complications. Patients with higher scores on STOP-BANG had increased rates of postoperative complications (19.6 percent vs. 1.3 percent) and longer hospital stays (3.6 days vs. 2.1 days) compared with patients who had lower scores.
"The high rate of postoperative complications in patients with obstructive sleep apnea syndrome may be owing to a variety of reasons," the authors wrote. "Central nervous system suppression owing to anesthesia, sedation and analgesia [pain relief] can foment sleep-disordered breathing and further asphyxia-related complications."
In addition, rapid eye movement (REM) sleep is diminished the night after surgery, followed by a period of REM rebound. The occurrence of breathing problems during REM sleep can consequently triple on the second and third postoperative nights.