Introduction:

Obtaining the maximum oxygen consumption (VO2max) in a direct way requires equipment and trained personnel, which are not available in most intensive care units. We modified the formula from Uths Niels et al: VO2max = 15 x (maximum heart rate during exercise/heart rate at rest), replacing the maximum rate during exercise with maximum heart rate for age and frequency at rest with heart rate at 24 hours from admission to the intensive care unit (ICU). VO2max modified = 15 x maximum heart rate for age/heart rate at 24 hours.

Objective:

To determine the threshold of maximum oxygen uptake estimated in patients with sepsis and septic shock that represents a prognostic marker.

Material and methods:

Cohort, prospective, longitudinal study. Patients over 18 years old admitted to the ICU with a diagnosis of sepsis. The maximum oxygen consumption upon the admission of patients with sepsis was calculated, and compared between groups based on VO2max modified. A bivariate analysis was performed using χ 2, ROC curve and relative risk.

Results:

Seventy-eight patients were analyzed, 42 men (54%), aged 68 ± 16 years; on 57%, the primary site of infection was the lungs, followed by the urinary tract (19%), with MODS 6 ± 3 points; 39% with sepsis and 61% with septic shock; 21 patients died (27%). The ROC curve was obtained for VO2max at 24 hours modified, with an AUC 0.70, CI from 0.64 to 0.89; p = 0.03, with a cutoff of 25 mL/kg/min, sensitivity and specificity of 70 and 70%, respectively. Patients with VO2max higher than 25 mL/kg/min have RR of 0.4 (CI 0.2-0.7) for mortality at 30 days.

Conclusions:

Modified VO2max could be a useful tool to identify septic patients with adequate reanimation. This trial suggests that a VO2max value calculated at 24 hours from ICU admission greater than 25 mL/kg/min is a reflection of good reanimation. However, future research is needed to corroborate the prognostic utility and to set a reanimation goal.

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