Review Question - QID 106901

This patient's clinical presentation is consistent with central sleep apnea.

Sleep apnea is defined as a sleep pattern in which there are several episodes of apnea per hour, with each episode lasting at least 10 seconds. The diagnosis is made with a sleep study, in which the "Apnea Hypopnea Index" is the number of apneic or hyponeic episodes per hour. An index of <5 is considered normal. While obstructive sleep apnea (OSA) is caused by pharyngeal collapse that impedes expiration, central sleep apnea is caused by a lack of central nervous system drive to breath. Since a tracheostomy tubes lies distal to the obstruction in OSA, patients who continue to have sleep apnea with a tracheostomy must have central sleep apnea.

Victor discusses the management of OSA. He notes that the most effective known treatment for OSA is continuous positive airway pressure (CPAP), which should be worn by patients during sleep. Patients with larger necks tend to need higher pressures in order to achieve adequate ventilation.

Martinez-Garcia et al. conduct a randomized, controlled trial to evaluate the effect of CPAP on hypertension in patients with known OSA. They note that 70% of patients with resistant hypertension are ultimately found to have OSA, and they find that the number of hours of CPAP use correlates directly with the extent of blood pressure reduction.

Illustration A is a diagram showing the mechanism of ventilatory impedance in OSA. Illustration B shows the progression of obstructive sleep apnea.

Incorrect Answers:
Answer 1: Although this is possible, ventilator settings are usually monitored closely.
Answer 3: This patient continues to have sleep apnea symptoms after placement of a tracheostomy tube, which is distal to the obstruction in OSA.
Answer 4: This patient does not have acute throat swelling or known exposure to precipitants.
Answer 5: There is no evidence of heart failure in this patient.