The most appropriate next step in management is polysomnography in this patient with likely undiagnosed obstructive sleep apnea (OSA). OSA may first come to clinical recognition immediately following a surgical procedure involving general anesthesia and/or narcotic analgesia that exacerbates the underlying pathophysiologic processes that contribute to OSA, and it may present with repeated episodes of postoperative hypoxia or as frank respiratory failure. The increased risk of postoperative complications associated with OSA highlights the importance of identifying the presence of the disorder preoperatively in high-risk patients. This patient has multiple risk factors for OSA, including age, male gender, obesity, hypertension, and a thick neck. His need for reintubation in the postanesthesia period suggests the possible presence of a sleep-related breathing disorder. Therefore, testing with polysomnography is indicated for further evaluation.

Overnight pulse oximetry has not been validated as a method for evaluating for OSA, primarily because of a high rate of false-positive and false-negative results. It would therefore not be an appropriate next study in this patient with a high pretest probability of OSA.

Multiple screening instruments are available that use clinical parameters to assess for the possible presence of OSA; these include the STOP-Bang questionnaire, Sleep Apnea Clinical Score, and the Berlin questionnaire. They are most commonly used to assess risk in patients with symptoms possibly attributable to OSA or as part of preoperative pulmonary assessment. This patient, however, already has a high probability of disease given his known risk factors for OSA along with his postoperative respiratory complications. A low score on a screening instrument would not alter the need for further evaluation.

Not pursuing further diagnostic information in this patient with multiple risk factors accompanied by postoperative pulmonary complications would be inappropriate.