To better understand the burden of morbidity and death in patients with compensated hypercapnic respiratory failure and the clinical factors contributing to these outcomes. Using a Pco2 greater than or equal to 50 mm Hg and a pH of 7.35–7.45 on arterial blood gas, the researchers did a query of the electronic medical record to identify individuals hospitalized at the University of Michigan who had compensated hypercapnia. The electronic medical record provided us with demographic and clinical information. They used Kaplan-Meier product-limit estimator to calculate the survival probability for Pco2 subgroups (50.0–54.9, 55.0–64.9, and 65.0 mm Hg). They built Cox proportional hazard models to study the link between Pco2 and all-cause mortality.

Four hundred ninety-one patients were found to have compensatory hypercapnia. The average age was 60.5 and 16.2. Males made up 57.4% of the population, while whites made up 86.2%. The mean pH was 7.38 ± 0.03, and the Pco2 was 58.8± 9.7 mm Hg, respectively. One thousand thirty patients were admitted to the hospital, with 44.4% of them having two or more admissions. The median total number of days spent in the hospital and intensive care unit was 21.0 (interquartile range [IQR], 11.0–38.0) and 7.0 (IQR, 3.0–14.0), respectively. A total of 217 patients (44.2%) died during 592 days. In univariate analysis, every 5 mm Hg increase in Pco2 was linked to a greater risk of mortality from any cause (hazard ratio, 1.09; 95% [CI]: 1.03–1.16; P = 0.004). After controlling for age, gender, BMI, and the Charlson comorbidity index, the connection remained (hazard ratio of 1.09 for every 5 mm Hg increase in Pco2; 95% CI: 1.02–1.16; P = 0.009). In terms of mortality, there was a statistically significant interaction between Pco2 and BMI (P = 0.01 for the interaction term).

Patients with compensated hypercapnic respiratory failure have a high mortality rate and need a lot of healthcare, and a greater Pco2 level is linked to a lower chance of survival. Increases in Pco2 put hypercapnic patients with obesity at a higher risk of death.