Pulmonary Hypertension, Hypoxemia, and Hypercapnia in Obstructive Sleep Apnea Patients

doi:10.1378/chest.96.4.729

Chest

Volume 96, Issue 4, October 1989, Pages 729-737

https://doi.org/10.1378/chest.96.4.729 Get rights and content

To define the parameters of respiratory insufficiency in OSA, 114 consecutive patients (108 men, six women) were prospectively studied. In addition to standard polysomnography, they underwent pulmonary function tests, right heart catheterization, and ventilatory response tests to hypercapnia. Nineteen patients (19 percent) had a resting PAP ≥ 20 mm Hg. Multiple regression analysis showed that FEV₁ and PaO₂ (both with a negative coefficient) and PaCO₂ (with a positive coefficient) significantly contributed to PAP. Thirteen patients (12 percent) had a PaCO₂ ≥45 mm Hg. A multiple regression analysis showed that FEV₁ and the minute ventilation at PETCO₂ = 60 mm Hg (both with a negative coefficient) and the cumulative apnea duration (with a positive coefficient) significantly contributed to PaCO₂. Thirty-seven patients (33 percent) had a PaO₂ ≤ 65 mm Hg. A multiple regression analysis showed that FEV₁ (with a positive coefficient) and the hypopnea + apnea index (with a negative coefficient) significantly contributed to PaO₂. These data confirm that impaired daytime pulmonary function (diffuse airway obstruction) contributes to the development of daytime pulmonary hypertension, hypoxemia, and hypercapnia in OSA patients. They show that the amount of sleep-related breathing disorders also plays a significant role.

Section snippets

Patients

As part of the evaluation of the severity of OSA before adequate treatment, 114 consecutive OSA patients (108 men, six women) referred to our Sleep Laboratory for symptoms evocative of OSA, including daytime somnolence (74 patients), snoring (25 patients), respiratory failure without a clear origin (eight patients), and observation of respiratory arrests during sleep (seven patients), underwent standard polysomnography (n = 114), pulmonary function tests (n = 112), right heart catheterization

RESULTS

The patients' anthropometric and main respiratory function, right heart catheterization, and polysomnographic data are given in Table 1. As a group, their values were within the normal range for all parameters studied except BMI. The individual values covered a wide range, from normal to pathologic (Fig 1). None of the observed distributions was significantly different from normal except that of mean minimal SaO₂.

DISCUSSION

In this group of 114 unselected OSA patients, 19 of 100 (19 percent) had daytime pulmonary hypertension, 37 of 112 (33 percent) had daytime hypoxemia, and 13 of 112 (12 percent) had daytime hypercapnia. Pulmonary hypertension may have been slightly underestimated because the 14 patients who did not undergo right heart catheterization were more overweight and had lower TLC, which may be contributory factors to pulmonary hypertension. However, using the model to predict the missing PAP values

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Chest

Clinical InvestigationsPulmonary Hypertension, Hypoxemia, and Hypercapnia in Obstructive Sleep Apnea Patients

Section snippets

Patients

RESULTS

DISCUSSION

Chest

Chest

Chest

Clin Chest Med

The sleep apnea syndrome

Annu Rev Med

Les syndromes d'apnées du sommeil de l'adulte. Sleep apnea syndromes in adults

Bull Eur Physiopathol Respir

Extreme obesity associated with alveolar hypoventilation: a pickwickian syndrome

Am J Med

Role of daytime hypoxemia in the pathogenesis of right heart failure in the obstructive sleep apnea syndrome

Am Rev Respir Dis

Sleep apnea and pulmonary hypertension

Klin Wochenschr

Daytime pulmonary hypertension in patients with obstructive sleep apnea syndrome

Am Rev Respir Dis

Clinical Investigations
Pulmonary Hypertension, Hypoxemia, and Hypercapnia in Obstructive Sleep Apnea Patients