A 55-year-old female with a BMI of 42 kg·m−2, presented for total thyroidectomy for a long-standing multinodular goiter. She appeared clinically euthyroid and her thyroid function tests were normal. Although mild retrosternal extension, high tracheal deviation and compression were demonstrated on the CT scan, the patient did not exhibit any compressive symptoms. On preoperative screening using the STOP-Bang Questionnaire, the patient was deemed to be at high risk for OSA in view of the presence of loud snoring, daytime sleepiness, history of hypertension, BMI more than 35 kg·m−2, and age above 50 years old. She offered the information that she was told “it was difficult to insert a breathing tube” during her previous surgery 10 years ago, but could not recall further details. Airway examination demonstrated good mouth opening, a short neck but good cervical range of movement, Mallampati Class IV and thyromental distance of 6 cm. Referral to sleep physician for sleep study evaluation was offered but the patient declined due to financial reasons. She also adamantly refused awake intubation despite a thorough explanation of the indications. After discussion with the surgeon and patient, the plan was to proceed with the surgery with risk mitigating strategies in view of patient's refusal for further investigations.
Obstructive sleep apnea (OSA) is the most common sleep-disordered breathing and is a growing problem with substantial economic cost. The presence of OSA in patients negatively influences postoperative outcomes.1 Severe perioperative complications (i.e., death and anoxic brain injury) directly related to OSA are being increasingly reported as the central contention of medical malpractice suits, with a substantial medico-legal burden.2,3 The prevalence of moderate to severe OSA among the general population is estimated at 13% in men and 6% in women between the ages of 30 and 70 years, with increased prevalence in the older age group of 50 to 70 years (17% in men, 9% in women). This reflects a substantial relative increase of OSA in the general population by 14% to 55% over the last two decades.4 The prevalence of OSA in surgical patients is even higher, with a quarter of the surgical population at high risk of OSA.5-7 Up to 90% of these patients may have undiagnosed OSA, and 40% of them may have moderate to severe OSA if subjected to testing by polysomnography (PSG).6,7
What Are the Perioperative Risks of a Patient with OSA?
OSA is an independent predictor of uncontrolled hypertension in patients less than 50 years old. Chronic nocturnal hypoxemia and hypercarbia trigger increased sympathetic activity, and the subsequent hemodynamic stress may lead to cardiovascular diseases through multiple mechanisms.8 Moderate to severe OSA is also associated with multiple medical comorbidities, including metabolic syndrome, obesity, insulin resistance, uncontrolled hypertension, heart failure, arrhythmias, coronary heart disease, and stroke.8...