Table 2 Investigative workup for etiology of chronic cough and sleep-apnea specific workup in patients with chronic cough
From: Chronic cough and obstructive sleep apnea in a community-based pulmonary practice
INVESTIGATIONS PERFORMED | N (%) |
|---|---|
Pulmonary Function Tests | Â |
Spirometry | 70/75 (93%) |
Diffusion capacity | 60/75 (80%) |
Lung volumes | 44/75 (59%) |
Methacholine challenge testing | 2/75 (3%) |
Six-minute walk test | 1/75 (1%) |
Radiologic studies | Â |
Chest X-ray | 54/75 (72%) |
Chest CT scan | 10/75 (13%) |
Sinus imaging | 10/75 (13%) |
Endoscopic studies | Â |
Bronchoscopy | 0/75 |
Upper GI endoscopy | 2/75 (3%) |
24 hour pH monitoring | 1/75 (1%) |
(Bravo* pH probe) | Â |
Laboratory studies | 5/75 (7%) |
SLEEP APNEA RELATED WORKUP | Â |
Sleep history obtained | 41/75 (55%) |
Abnormal | 36/75 (48%) |
Screening overnight oximetry | 6/75 (8%) |
Abnormal | 6/75 (8%) |
Polysomnography | 38/75 (51%) |
   Sleep disordered breathing | 33/75 (44%) |
No OSA (AHI < 5) | 4/75 (5%) |
Mild OSA (AHI 6-15) | 6/75 (8%) |
Moderate OSA (AHI 16-30) | 6/75 (8%) |
Severe OSA (AHI >31) | 14/75 (19%) |
   Periodic limb movement disorder | 1/75 (1%) |
   Sleep efficiency (mean) | 89% |
   Arousal index (mean) | 17 |
   Oxygen saturation (mean) | 91% |
   Lowest oxygen saturation (mean) | 78% |