Chest
Volume 119, Issue 4, April 2001, Pages 1102-1107
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Clinical Investigations: Control of Breathing
The Obesity Hypoventilation Syndrome Can Be Treated With Noninvasive Mechanical Ventilation

https://doi.org/10.1378/chest.119.4.1102Get rights and content

Study objectives

To assess the effectiveness of nasal noninvasive mechanical ventilation (NIMV) in patients with obesity hypoventilation syndrome (OHS).

Design

Clinical assay that compares two groups of patients with hypercapnic respiratory failure, one group with OHS and the other group with kyphoscoliosis, in their basal situation and after 4 months of treatment with nocturnal NIMV. Thirty-six patients (22 patients with OHS and 14 patients with kyphoscoliosis) completed the study protocol.

Results

The frequency of symptoms, such as morning headache, morning drowsiness, dyspnea, and leg edema, improved in a statistically significant way in both groups of patients. The sleepiness improved only in the group with OHS. The comparison of frequency of symptoms between both groups of patients after NIMV treatment did not present statistically significant differences. In the resting situation and without nasal ventilation in place, the Po2 (mean ± SD) changed from 51 ± 10 to 64 ± 11 mm Hg (p < 0.001) and Pco2 from 58 ± 10 to 45 ± 5 mm Hg (p < 0.001) when the patients with OHS were treated with NIMV. In the group of patients with kyphoscoliosis, likewise without nasal ventilation in place, Po2 changed from 53 ± 6 to 65 ± 5 mm Hg (p < 0.001) and Pco2 from 59 ± 11 to 45 ± 4 mm Hg (p < 0.001) with NIMV treatment. When we compared Po2 and Pco2 in both groups of patients at the beginning and at the end of NIMV treatment, we did not find statistically significant differences between OHS and kyphoscoliosis.

Conclusions

NIMV improves the clinical symptoms and the respiratory failure of patients with OHS to a similar degree to that reported for diseases in which its use is completely established, such as kyphoscoliosis. Therefore, NIMV could be an alternative to the treatment of patients with OHS.

Section snippets

Study Design

This clinical trial compared patients at baseline and after 4 months of treatment with NIMV. There were two groups of patients: one group with OHS and one group with kyphoscoliosis. The inclusion criteria for the patients with OHS were as follows: body mass index> 33, failure of dietetic treatment to induce weight loss with persistence of hypercapnic respiratory failure (Pco2 > 47 mm Hg) for at least 3 months before NIMV treatment, and refusal of surgical treatment of obesity based either on

Follow-up

Sixteen patients (73%) from the OHS group and 12 patients (86%) from the kyphoscoliotic group had been admitted to the hospital for respiratory failure at least once in the previous 3 years. During this time, the number (mean ± SD) of emergency visits per patient was 5.2 ± 2.1 visits for those in the OHS group and 4.6 ± 1.7 visits for those in the kyphoscoliotic group. Neither emergency visits nor hospitalizations occurred during the follow-up period. All the patients were receiving NIMV

Discussion

This study shows that NIMV is effective in alleviating the symptoms and reversing the respiratory failure of patients with OHS. The effect is similar to that seen in patients with kyphoscoliosis.

The mechanism by which OHS causes respiratory failure has not been well established, although a central component characterized by a defect in the respiratory controller appears to be the most important in causing it.9 A decreased ventilatory response to CO2 rebreathing has been generally observed.10 In

ACKNOWLEDGMENT

We are indebted to Verónica Rodríguez for assistance in the preparation of the article.

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This work was performed at “San Pedro de Alcántara” Hospital, Cáceres, Spain.

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