PURPOSE: To determine whether obese patients who have an elevated serum bicarbonate are more likely to have pulmonary hypertension compared to those who have a normal serum bicarbonate.
METHODS: Retrospective case control study focused in obese male and female patients, 18 years-old and older admitted to the general medical floor at Albert Einstein Medical Center from December 2003 to December 2008. Selected patients had echocardiogram performed within 6 months prior to admission and no evidence of COPD or CHF or other established causes of pulmonary hypertension. The patients were divided in two groups: serum bicarbonate of 27 mEq/l or above and those that had a serum bicarbonate less than 27 mEq/l (control group) on admission.
RESULTS: Of the 291 patients that fulfilled the above inclusion criteria, 96 had Pulmonary Artery Systolic Pressure reported; among these, 41 were eligible for the study. The control group had 22 patients and the elevated bicarbonate group had 19. The two groups were similar regarding demographics, BMI and presence of comorbidities. Pulmonary hypertension (estimated by echocardiogram) was present in 13 patients (68.4%) in the elevated serum bicarbonate group compared to 12 (54.5%) in the control group (P >0.05).
CONCLUSION: Preliminary results show that obese patients with an elevated serum bicarbonate had a higher incidence of pulmonary hypertension compared to the control group, but the difference is not statistically significant. The absence of statistical significance may be related to the small sample analyzed. We expect more conclusive results as more patients are included in the study.
CLINICAL IMPLICATIONS: Elevated serum bicarbonate due to metabolic compensation for chronic respiratory acidosis is a common finding. Recent studies suggest that the test could be used as a screening tool for hypercapnia with the advantages that it is readily available, physiologically sensible and less invasive. Early detection of obesity hypoventilation syndrome and its complications is essential, appropriate treatment improves or stabilizes pulmonary hypertension and quality of life, decreases morbidity and mortality therefore decreasing health care expenses and hospital readmission rates.
DISCLOSURE: Alejandra Carpio, No Financial Disclosure Information; No Product/Research Disclosure Information