Clinical significance of early lactate clearance rate in patients with respiratory failure

Abstract

To investigate the clinical significance of early lactate clearance rate in patients with respiratory failure. A prospective clinical trial was carried out.A hundred and ten patients with respiratory failure, including 59 males and 51 females, with mean age (59 +/- 22) yrs were admitted into the respiratory ward in affiliated Zhongda Hospital of Southeast University from August 2005 to April 2009. There were 50 cases of type I respiratory failure and 60 cases of type II respiratory failure. The acute physiology and chronic health evaluation II (APACHE II) score was evaluated, 6 h arterial blood lactate and arterial blood gas analysis were measured before and after the treatment, and then 6 h lactate clearance rate were calculated in all the 110 patients. Patients were divided into the survival group (80 cases) and the death group (28 cases) from hospital admission to the study end of discharging or death of the patients. The high lactate clearance rate group (68 cases) was defined as a lactate clearance rate > or = 10%, and the low lactate clearance rate group (42 cases) with a lactate clearance rate < 10%. Data were compared between the survival group and the death group, the high lactate clearance rate group and the low lactate clearance group. T test was used in the comparison between groups, group paired t test was used in the comparison between before and after the treatment, and chi-square test was used in the comparison between rates. There were no statistical differences in arterial blood lactate, APACHE II score, pH value, PaO2, PaCO2 and oxygenation index between the survival group and the death group or between the high lactate clearance rate group and the low lactate clearance rate group before the treatment. There were statistical differences in arterial blood lactate, PaO2, PaCO2 and oxygenation index between groups 6 h after the treatment (P < 0.05) except for pH values and APACHE II score. The 6 h lactate clearance rate of the survival group (31% +/- 11%) was significantly higher than that of the death group (14% +/- 6%) (chi2 = 161.2, P < 0.01). Mortality of the high lactate clearance rate group (15%) was significantly lower than that of the low lactate clearance rate group (43%) (chi2 = 178.4, P < 0.01). Early lactate clearance rate could be used as a marker for prognosis of patients with respiratory failure.