Clinical Evaluation of potential Sleep Apnea patients

It is important to take a good sleep history in any patient with risk factors or clinical features suggesting the possibility of OSA (see Fig. 67-4). Patients may notice several symptoms during wakefulness. Excessive daytime sleepiness is the most common complaint. Initially, daytime sleepiness may be mild and develops during relaxing activities such as reading or watching TV. As the disorder progresses, daytime sleepiness becomes more irresistible. Unwanted sleep may eventually interrupt activities such as driving a motor vehicle. By-products of excessive daytime sleepiness such as inability to concentrate, memory and judgment impairment, irritability, depression, and personality changes also become more common as the disorder progresses. Decreased libido and impotence are common complaints, although the etiology is unknown. Early morning headache is occasionally reported and may be related to the nocturnal episodes of hypercapnia causing increased cerebral blood flow and edema.

Patients do not always realize that their sleep quality is poor and disrupted by frequent, brief arousals. However, they may complain of restless sleep or being awakened by their own snoring or a choking sensation. The sleeping partner usually describes loud snoring, although not all snorers have sleep apnea. It is more helpful if the sleeping partner has observed frequent apneas associated with snoring cessation and terminated by snorting, gasping, or restless movement.

On physical examination, patients are often overweight. The neck may be short and thick. The upper airway should be examined for nasal obstruction, large tonsils, an elongated palate, macroglossia, micrognathia, or pharyngeal tumor. Systemic hypertension may be present. Signs of left ventricular dysfunction, pulmonary hypertension, right heart failure, polycythemia, and chronic alveolar hypoventilation may develop in severe OSA. Neurologic examination may reveal excessive sleepiness and impaired memory and cognition in severe cases.

Routine laboratory tests are of limited value in the diagnosis of OSA. Screening tests for hypothyroidism and acromegaly should be performed if these disorders are suspected based on clinical findings. A minority of patients with very severe OSA have polycythemia or an elevated arterial carbon dioxide tension on awake arterial blood gas testing.