Obesity-Hypoventilation Syndrome: Baseline Hemodynamic Status and Impact of non-Invasive Ventilation

Obesity-hypoventilation syndrome (OHS) is a risk factor for heart failure (HF). Some studies associate the use of non-invasive ventilation (NIV) with changes in hemodynamic parameters. Our objective was to describe the hemodynamic status of a group of patients with OHS and to study the effect of NIV.

Patients with stable OHS treated with NIV were included in this cross-sectional repeated measurements study. Hemodynamics were measured by bioimpedance: 30minutes at baseline and another 30minutes on NIV. Cardiac output (CO), cardiac index, and systolic volume were measured. The CO calculated for each patient expressed as a percentage of the lower limit of normal (LLN) was taken as reference, and 2 groups were formed: patients without HF and normal CO (≥ 100% of LLN) and patients with HF and low CO (< 100% of LLN). The Mann-Whitney U test was used to compare independent variables and the Wilcoxon test was used for paired variables, with significance set at P<.05.

The final sample comprised 36 patients, aged 66 (± 8) years, 19 (52%) men. In 17 (46%) patients, HF was detected with a CO of 3.7 l/min (66%) compared to the group without HF, whose CO was 7 l/min (107%). After NIV, patients with HF showed improvement in CO (4.5 l/min (77%), P=.009, while the non-HF group remained unchanged, with CO 6.8 l/min (104%), P=.2.

A total of 46% of patients with stable OHS present HF; NIV improves hemodynamics and does not affect patients with normal CO.