Chest
Volume 92, Issue 5, November 1987, Pages 807-813
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Determinants of Hypercapnia in Occlusive Sleep Apnea Syndrome

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To assess the relative contributions of age, gender, obesity, pulmonary function, and the severity of sleep-induced respiratory abnormalities to the development of alveolar hypoventilation in patients with occlusive sleep apnea syndrome, prospective data from 111 patients with occlusive sleep apnea were analyzed by stepwise logistic and multiple regression techniques. The significant variables in a logistic regression model predicting the presence of hypercapnia were daytime arterial oxygen pressure (PaO2; p<0.0001) and gender (p<0.04), the latter reflecting the higher number of hypercapnic women in our patient population. Multiple regression analysis performed in the hypercapnic group to study the determinants of the severity of elevation of arterial carbon dioxide tension (PaCO2) revealed significant contribution from the PaO2, the apnea-plus-hypopnea index (AHI), and the percent predicted forced vital capacity (r2 = O.56; p<0.0001), whereas in the normocapnic patients, PaCO2 related to PaO2 only. These results suggest that daytime hypoxemia, mechanical impairment of the respiratory system due to obesity or obstructive airway disease (or both), and the severity of sleep-induced respiratory abnormalities as assessed by AHI contribute to the severity of carbon dioxide retention in patients with occlusive sleep apnea in a multifactorial fashion.

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MATERIALS AND METHODS

One hundred and fifty-two consecutive adult patients undergoing nocturnal polysomnography at the University of Illinois Hospital were prospectively considered for entry into the study during a two-year period. This patient population is derived from the inpatients and outpatients of our institution, as well as referrals from community hospitals and clinics. From this population, patients with occlusive sleep apnea defined on the basis of a history of hypersomnolence and snoring, and an

RESULTS

There were 75 men and 36 women, of whom 22 and 19, respectively, were hypercapnic at the time of presentation. The chronicity of hypercapnia was evident by the mean value (± 1 SE) for arterial pH, which for hypercapnic individuals was 7.39±0.01.

The mean (±1 SE) and the range for age, weight-height ratio, arterial blood gas levels, and selected pulmonary function and sleep study variables for the hypercapnic and normocapnic patients are shown in Table 1. The patient population was predominantly

DISCUSSION

The results of this study suggest that the development of alveolar hypoventilation in patients with occlusive sleep apnea syndrome is indeed multifactorial. Conflicting results from previous studies regarding the importance of weight, muscle function, obstructive disease of the airways, and the severity of sleep-induced respiratory abnormalities1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 1, 16, 17, 18, 19 may have arisen from the small number of hypercapnic patients studied. In addition to

ACKNOWLEDGMENT

We thank Dr. Patricia Langenberg for her helpful suggestions regarding the statistical methods.

REFERENCES (38)

  • BurwellCS et al.

    Extreme obesity associated with alveolar hypoventilation: a pickwickian syndrome

    Am J Med

    (1956)
  • NaimarkA et al.

    Compliance of the respiratory system in health and obesity

    J Appl Physiol

    (1960)
  • SharpJT et al.

    Effects of mass loading the respiratory system in man

    J Appl Physiol

    (1964)
  • LopataM et al.

    Mass loading, sleep apnea and the pathogenesis of obesity hypoventilation

    Am Rev Respir Dis

    (1982)
  • FilbertR et al.

    Respiratory control and work of breathing in obese subjects

    J Appl Physiol

    (1961)
  • LourencoRV

    Diaphragm activity in obesity

    J Clin Invest

    (1969)
  • EmirgilC et al.

    The effects of weight reduction on pulmonary function and the sensitivity of the respiratory center in obesity

    Am Rev Respir Dis

    (1973)
  • GuilleminaultC et al.

    Progressive improvement of apnea index and ventilatory response to CO2 after tracheostomy in obstructive sleep apnea syndrome

    Am Rev Respir Dis

    (1982)
  • JonesJB et al.

    Oxyhemoglobin saturation during sleep in patients with and without the obesity-hypoventilation syndrome

    Chest

    (1986)
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    Supported by the Medical Research Service of the Veterans Administration and the Chicago Lung Association.

    Published in an abstract form in the American Review of Respiratory Diseases (1986; 133:A342).

    Manuscript received October 2; revision accepted March 4

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