Clinical Utility of Venous Blood Gas Analysis for the Evaluation of Psychogenic Hyperventilation in the Emergency Department.

Background Patients with psychogenic hyperventilation frequently visit emergency departments (EDs). Arterial blood gas (ABG) analysis is performed to evaluate patients with dyspnea. This may show respiratory alkalosis in patients with hyperventilation. ABG may also reveal elevated serum lactate levels, although psychogenic hyperventilation syndrome is a benign condition. However, arterial puncture is a painful and risky procedure. We hypothesized that venous blood gas (VBG) analysis would be sufficient for evaluating patients with suspected psychogenic hyperventilation. Objectives To compare the clinical utility of VBG analysis with ABG analysis for evaluating psychogenic hyperventilation. Methods This was a single-center retrospective cross-sectional study of patients aged ≥18 years with psychogenic hyperventilation attending a tertiary care hospital. We extracted data on age, sex, vital signs, blood gas components, and serum lactate. Spearman's rank correlation coefficient (ρ) was used to examine the associations between the serum lactate levels and the carbon dioxide partial pressure (PCO2) in the ABG and VBG groups. Results A total of 236 patients (ABG group, n=57; VBG group, n=179) were included in the analysis. Both the ABG and VBG groups had respiratory alkalosis and similarly elevated serum lactate levels (p=0.44). The PCO2 and serum lactate levels were inversely correlated, and the ρ values were -0.74 and -0.50 for the ABG and VBG groups, respectively (both p<0.001). In addition, the bicarbonate ion ([Formula: see text]) level was inversely correlated with the serum lactate level, and the pH was positively correlated with the serum lactate levels in both the ABG and VBG groups. Conclusions Among patients with psychogenic hyperventilation, respiratory alkalosis, and the correlation between the PCO2 and serum lactate levels were similar in the ABG and VBG groups, indicating that VBG analysis might be used as an alternative to ABG analysis for evaluating psychogenic hyperventilation.