[Study of automated acid-base mapping on diagnose and treatment of community acquired pneumonia in emergency department].

Objective: To analyze the value of automated acid-base mapping on diagnose and treatment of patients with community acquired pneumonia (CAP) in emergency department.

Methods: According to medical history, pulmonary function test, diagnosing guideline of chronic obstructive pulmonary disease (COPD), 111 patients with CAP were divided into two groups: single CAP group (n=56) and COPD complicated with CAP group [acute exacerbation of chronic obstructive pulmonary disease (AECOPD) group, n=55]. After enquiring medical history, arterial blood samples were drawn for blood gas analysis and automated acid-base mapping was analyzed.

Results: Arterial blood gas analysis showed arterial carbon dioxide partial pressure (PaCO(2)), HCO(3)(-), base excess of AECOPD group were obviously higher than those in CAP group (PaCO(2): 7.714±2.414 kPa vs. 5.896±1.308 kPa, HCO(3)(-): 30.767±7.185 mmol/L vs. 25.014±3.043 mmol/L, BE: 4.345±5.371 mmol/L vs. -0.354±3.180 mmol/L, all P<0.01). Automated acid-base mapping showed acid-base disturbance of AECOPD group was 89.1% and CAP group was 66.1%. Chi-square analysis were done for patients of normal (10.9%, 33.9%), acute respiratory acidosis (12.7%, 14.3%), chronic respiratory acidosis (49.1%, 10.7%), respiratory alkalosis (7.3%, 14.3%), metabolic acidosis (12.7%, 17.9%), metabolic alkalosis (12.7%, 8.9%) between AECOPD group and CAP group, and statistical significance was found between AECOPD group and single CAP group (χ (2)=24.421, P=0.001). Advanced Chi-square analysis for patients of normal, acute respiratory acidosis, respiratory alkalosis, metabolic acidosis, metabolic alkalosis were done and showed no statistical difference (χ (2)=5.280, P=0.260). It is indicated chronic respiratory acidosis occurrences rate in AECOPD patients was higher than single CAP patients.

Conclusions: Our study demonstrated that automated acid-base mapping may be helpful for emergency physician to rapidly recognize multi-acid-base disturbance in patients with CAP, and to promptly identify acute or chronic phase of respiratory disease.