Hypercapnia as a marker of ICU admission and prolonged hospitalization in patients with community-acquired pneumonia

Abstract

Background: Hypoxemic respiratory failure is well known prognostic marker in community acquired pneumonia (CAP) while a PaCO2 level is not considered as a prognostic indicator. Objective: To examine the association between abnormal Paco 2 and ICU admission, length of stay and in-hospital mortality in patients with CAP. Methods: A prospective study was conducted in hospitalized patients with CAP at tertiary care hospital in Karachi, Pakistan. Arterial blood gas analyses were obtained on admission. Multivariate analyses were performed using in-hospital mortality and ICU admission and length of stay as the dependent measures. Results: Total 115 patients enrolled. The mean age was 60.20 ± 17.0 years and 61 (53%) were male. Hypocapnia (PaCO2 2 > 45 mm Hg) in 22(19.1%) patients. Overall mortality was found in 16 (13.9%) and there was no statistical difference among groups (p: 0.74).After adjusting for severity of illness, hypercapnic patients had greater length of hospital stay (OR: 1.13; 95% CI, 1.01-1.27; p: 0.01), higher need for Noninvasive ventilation (NIV) on admission (OR: 3.07; 95%CI .07-8.75; p: 0.04) and ICU admission/ mechanical ventilation (OR: 0.45; 95% CI, 0.16-1.41; p: 0.23) as compare to hypocapnic patients.When COPD were excluded from the analysis, the differences persisted. Conclusion: In hospitalized patients with CAP, hypercapnia was associated with an increased need for NIV use and prolonged length of stay as compared to hypocapnic patients. Therefore, hypercapnia should be considered as important severity criteria to identify patients who will require a higher level of care and prolonged hospitalization.