Pulmonology (Sep 2021)
Noninvasive ventilatory support in morbid obesity
Abstract
Background: In the conventional management of the morbidly obese that normalizes the apnea-hypopnea index (AHI), CO2 levels often remain elevated. Methods: A retrospective review of morbidly obese patients using volume preset settings up to 1800 ml to positive inspiratory pressures (PIPs) of 25–55 cm H2O, or pressure control at 25–50 cm H2O pressure via noninvasive interfaces up to continuously (CNVS). Results: Twenty-six patients, mean 55.6 ± 14.8 years of age, weight 108–229 kg, mean BMI 56.1 (35.5–77) kg/m2, mean AHI 69.0 ± 24.9, depended on up to CNVS for 3 weeks to up to 66 years. There were eleven extubations and seven decannulations to CNVS despite failure to pass spontaneous breathing trials. Thirteen were CNVS dependent for 92.2 patient-years with little to no ventilator free breathing ability (VFBA). Six used NVS from 10 to 23 h a day, and others only for sleep. Fifteen patients with cough peak flows (CPF) less than 270 L/m had access to mechanical insufflation-exsufflation (MIE) in the peri-extubation/decannulation period and long-term. The daytime end-tidal (Et)CO2 of 14 who were placed on sleep NVS without extubation or decannulation to it decreased from mean EtCO2 61.0 ± 9.3–38.5 ± 3.6 mm Hg and AHI normalized to 2.2. Blood gas levels were normal while using NVS/CNVS. Pre-intubation PaCO2 levels, when measured, were as high as 183 mm Hg before extubation to CNVS. Conclusions: Ventilator unweanable morbidly obese patients can be safely extubated/decannulated and maintained indefinitely using up to CNVS rather than resort to tracheotomies.
