Is Serum Lactate Level a Prognostic Factor for the Incidence and Mortality of Ventilator-Associated Pneumonia Among Poisoned ICU-Admitted Patients?

Abstract

Background: Lactate level is known to increase among the majority of patients with toxicity. This study aimed to determine whether lactate level upon admission is higher among patients with ventilator-associated pneumonia (VAP). Objectives: We aimed to determine whether serum lactate level is associated with the increased risk of VAP in intensive care unit (ICU)-admitted patients with toxicity. Methods: This retrospective study was conducted in a training medical poisoning center in Iran, using convenience sampling. A total of 157 poisoned patients, aged ≥ 13 years, who were admitted to the ICU over the past seven months, were included in the study. Subjects were categorized into two groups, based on their VAP diagnosis (VAP-positive and non-VAP) and the outcomes (surviving or non-surviving). The VAP-positive patients were compared with others with regard to the mean level of serum lactate level upon admission. Additionally, non-surviving patients were compared with their surviving counterparts. Results: Overall, 71 (45.2 %) VAS-positive cases were reported, in addition to 36 cases of mortality. Alkaline phosphatase (ALP) was the most common toxic agent (36%), followed by methanol. Significant differences were noted between the groups in terms of Simplified Acute Physiology Score-II (SAPS-II), Glasgow Coma Scale (GCS) score, length of ICU stay, and percentage of ventilation process. The mean levels of lactate at admission were 3.71 ± 3.35 and 4.19 ± 4.09 among VAP-positive and non-VAP patients, respectively; the difference was not statistically significant. Also, non-surviving patients had a longer ICU stay (12.20 days), compared to surviving patients (5.39) (P = 0.008). Moreover, admission lactate level was 7.06 ± 5.29 mmol/L among non-surviving patients and 3.01 ± 2.53 among surviving cases (P < 0.001). Conclusions: Based on the findings, the mortality rate was 22.9% among poisoned patients with an elevated serum lactate level. We can conclude that mortality is associated with toxicants, but not the occurrence of VAP; in fact, VAP scenarios do not elevate serum lactate level.