Two-Hour Lactate Clearance Predicts Negative Outcome in Patients with Cardiorespiratory Insufficiency

Sean Scott,Giovanna Guiotto,Fernando Schiraldi,Vittorio Antonaglia,Fiorella Paladino

doi:10.1155/2010/917053

Abstract

Objective. To evaluate 2-hour lactate clearance as a prognostic marker in acute cardiorespiratory insufficiency. Design. Prospective observational study. Setting. Emergency Department (ED) and 16-bed medical High Dependency Unit (HDU). Methods and Main Results. 95 consecutive admissions from the ED for acute cardiorespiratory insufficiency were prospectively enrolled. Arterial lactate concentration was assessed at ED arrival and 1, 2, 6, and 24 hours later. The predictive value of 2-hour lactate clearance was evaluated for negative outcomes defined as hospital mortality or need for endotracheal intubation versus positive outcomes defined as discharge or transfer to a general medical ward. Logistic regression and ROC curves found 2-hour lactate clearance >15% was a strong predictor of negative outcome (P < .0001) with a sensitivity of 86% (95%CI = 67%–95%) and a specificity of 91% (95%CI = 82%–96%), Positive predictive value was 80% (95%CI = 61%–92%), and negative predictive value was 92% (95%CI = 84%–98%). Conclusions. Systematic monitoring of lactate clearance at 2 hours can be used in to identify patients at high risk of negative outcome and perhaps to tailor more aggressive therapy. Equally important is that a 2-hour lactate clearance >15% is highly predictive of positive outcome and may reassure clinicians that the therapeutic approach is appropriate.

Highlights

Acute cardiorespiratory failure from any cause creates an imbalance between energy supply, demand, and consumption
At enrolment 56 patients were in acute pulmonary oedema (68%), 25 patients had acute respiratory failure for severe exacerbation of COPD (21%), 7 were in cardiogenic shock (6%), and 5 patients presented with acute myocardial infarction. 34 patients required noninvasive positive pressure ventilation (NPPV) (43%)
Lactate at baseline was not different between groups but 2-hour lactate and 2-hour lactate clearance were significantly worse in patients with negative outcomes (Table 1)

Summary

Introduction

Acute cardiorespiratory failure from any cause creates an imbalance between energy supply, demand, and consumption. A high lactate concentration associated with a low blood pH is useful to depict the gravity of such a mismatch [1]. Lactate overproduction can be promptly removed from blood if renal and hepatic perfusion and function are near normal [2, 3]. A huge bulk of research has been focused on lactate production/removal in critically ill patients. Some evidence suggests that persistent elevation in lactate is associated with high mortality rate [4,5,6]. It is generally agreed that the longer lactate levels remain high, the worse the prognosis [7, 8]. A question remains regarding the timing needed to guide the therapy based on evaluation of lactate clearance [9]

Methods

Results

Discussion

Conclusion