Prognosis of patients presenting extreme acidosis (pH <7) on admission to intensive care unit

Abstract

Purpose: The purpose was to determine prognosis of patients presenting extreme acidosis (pH <7) on admission to the intensive care unit (ICU) and to identify mortality risk factors.

Materials and methods: We retrospectively analyzed all patients who presented with extreme acidosis within 24 hours of admission to a polyvalent ICU in a university hospital between January 2011 and July 2013. Multivariate analysis and survival analysis were used.

Results: Among the 2156 patients admitted, 77 patients (3.6%) presented extreme acidosis. Thirty (39%) patients suffered cardiac arrest before admission. Although the mortality rate predicted by severity score was 93.6%, death occurred in 52 cases (67.5%) in a median delay of 13 (5-27) hours. Mortality rate depended on reason for admission, varying between 22% for cases linked to diabetes mellitus and 100% for cases of mesenteric infarction (P = .002), cardiac arrest before admission (P < .001), type of lactic acidosis (P = .007), high Simplified Acute Physiology Score II (P = .008), and low serum creatinine (P = .012).

Conclusions: Patients with extreme acidosis on admission to ICU have a less severe than expected prognosis. Whereas mortality is almost 100% in cases of cardiac arrest before admission, mortality is much lower in the absence of cardiac arrest before admission, which justifies aggressive ICU therapies.

Keywords: Acidosis; Lactate; Prognosis.