Relationship of Hospital Mortality with Metabolic Acidosis Severity in Critically Ill Patients

Metabolic acidosis (MA) is a common pathologic process with fatal consequences in critically ill (CI) patients. The more the severity of acidosis the more mortality rate is expected. To evaluate the relationship of hospital mortality with MA severity in CI patients admitted to emergency department (ED).

In this prospective cohort study, we enrolled CI patients (based on physician clinical assumption), most at level 1 or 2 emergency severity index triage system. Patients were followed and evaluated in 2 parallel groups, one with and the other without MA. The severity of acidosis, chief complaints, final diagnosis, demographic data, acute physiologic assessment and chronic health evaluation II (APACHE II) score, serum lactate and bicarbonate level, need for intubation and mechanical ventilation, admission ward, hospital length of stay and in hospital mortality were compared between the 2 groups.

A total of 1811 CI patients including 60.2% males and 39.8% females with and without MA were evaluated. The most common age range was 65-55 years old (31.7%) with the meanSD of 61.348.23. The most common complaints and diagnoses were weakness (40.5%) and pneumosepsis (35.1%), respectively. Patients with severe acidosis had higher lactate level and APACHE II score (p<0.05). Mortality rate was 10.4%. Most of our cases had severe MA. Expired cases had higher lactate level and APACHE II score (p<0.05).

Lactate level, bicarbonate level and APACHE II score were all significant independent predictors of hospital mortality in CI patients.