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

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). 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. 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. 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). 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.