HYPERLACTATEMIA DURING ACUTE SEVERE ASTHMA

Objective. To evaluate arterial lactate levels during treatment of acu te severe asthma (ASA) and the prognostic value of arterial hyperlacta temia in ASA. Design: Prospective study. Setting: A respiratory intens ive care unit (ICU) of a university hospital. Patients: 29 consecutive patients admitted to the ICU for ASA not intubated on admission and w ith a peak expiratory flow (PEF) < 150 l/min or an arterial carbondiox ide tension (PaCO2) > 40 mm Hg. All patients received standardized tre atment during the first 24 h including i.v. and nebulized salbutamol, i.v. theophylline, and dexamethasone. Measurements and results: Arteri al lactate levels were serially measured by an enzymatic method during the first 24 h following admission. On admission, the mean arterial l actate level was 3.1 +/- 0.38 mmol/l (range 1.1-10.4); 17 patients (59 %) had arterial hyperlactatemia with a lactate level > 2 mmol/l. No di fference was found in lactate levels between patients with progressive ly worsening asthma and those with an acute onset of severe asthma. No correlation was found between arterial lactate levels on admission, o n the one hand, and respiratory rate (RR), heart rate, PEF, pH, PaCO2, arterial oxygen tension, potassium, phosphorus, creatine kinase, or t ransaminase values on admission, on the other hand. All patients devel oped an important but transient increase in arterial lactate levels du ring treatment, with a peak at 7.72 +/- 0.46 mmol/l and a mean elevati on of 4.62 +/- 0.45 mmol/l (range 0.4-12.1), from the initial admissio n value contrasting with a significant clinical improvement assessed b y RR, PEF, and arterial blood gas parameters. Conclusion: This study s uggests that, in ASA, arterial hyperlactatemia is frequently present o n admission to the ICU. Delayed hyperlactatemia is a constant finding during treatment of ASA. Initial or delayed hyperlactatemia seems of n o prognostic value because none of the patients required mechanical ve ntilation, The effects of therapy for acute asthma on lactate metaboli sm still need to be studied.