Characteristics of Obese Patients with Acute Hypercapnia Respiratory Failure Admitted in the Department of Pneumology: An Observational Study of a North African Population

Background. Acute hypercapnic respiratory failure (AHRF) is a common life-threatening event in patients with obesity hypoventilation syndrome (OHS). Objectives. To study the clinical pattern, noninvasive ventilatory support, as well as the short- and long-term outcomes of patients with OHS admitted in a ward because of AHRF. Methods. We conducted a retrospective cohort study including all adults with OHS , admitted in a 90-bed-ward for AHRF. Results. A total of 44 patients were included. Fifteen (34.1%) and 29 (65.9%) patients were diagnosed with malignant OHS (mOHS) and nonmalignant OHS (non-mOHS), respectively, while 36 (81.8%) had coexisting obstructive sleep apnea hypopnea syndrome (OSAHS). Patients with mOHS had a significantly higher rate of heart failure (100% vs. 31%; ), chronic renal insufficiency (CRI) (73.3% vs. 41.4%; ), and dyslipidemia (66.7% vs. 34.5%; ) than those with non-mOHS. The mean forced vital capacity (FVC) in our patients was of of the predicted value, lower than what is usually reported in stable patients with OHS. At hospital admission, more than two-thirds (, 77.3%) were misdiagnosed as having asthma exacerbation (, 4.9.1%), chronic obstructive pulmonary disease (COPD) exacerbation (, 27.3%) and/or heart failure (, 65.9%). Acute pulmonary oedema (ACPE) (, 36.4%) and acute viral bronchitis (, 27.3%) were the main identified causal factors, while no cause could be determined in 5 (11.4%) patients. Noninvasive positive pressure ventilation (NIPPV) using bilevel positive airway pressure (BIPAP) was very highly effective to treat AHRF, with only 2.27% of patients failing the modality. Median overall duration of ventilation was 9 hours per day (1.3–20) and was significantly longer in patients with mOHS than in those with non-mOHS (10 [6–18] vs. 8 [1.3–20], respectively; ). Forty two of the forty-three patients discharged alive were treated with BIPAP or continuous positive airway pressure (CPAP) in 26 and 16 patients, respectively. The probability of survival was 90% at 12 months, while the probability of readmission for a new episode of AHRF was 56% at 6 months and 22% at 12 months, respectively. Conclusion. AHRF in OHS patients is a life-threatening event which can be successfully and safely treated with BIPAP, with a low long-term mortality even in patients with mOHS.