Introduction: Definitive guidance or supporting literature to guide the choice of weight-based or flat rate dosing of norepinephrine use for hemodynamic support in septic shock is variable. With the utilization of a weight-based approach, there is an increased potential for side effects such as tachycardia. The purpose of this study was to retrospectively evaluate the incidence of tachycardia as defined by any heart rate ≥110 beats per minute (BPM), in obese patients compared to normal BMI patients receiving norepinephrine during acute septic shock. Methods: A retrospective analysis was conducted in patients who were identified as normal weight or obese, admitted to intensive care units at two hospitals, receiving norepinephrine as a first line vasopressor for the treatment of septic shock. Results: A total of 240 patients were included in this study, 97 in the normal weight BMI,105 obese BMI, and 38 in the morbidly obese BMI group. Baseline characteristics between the three groups were similar with average age being 65 54.5, 76.5 and 52.9% female. There was a significant difference in dosing weights between the three classes, reflective of the BMI stratification (p= < 0.0001). A total of 122 patients (50.8%) overall had an incidence of tachycardia. However, there was no significant difference between the three BMI groups (p=0.4845). Additionally, there was no significant difference in new start arrythmias (p=0.2584), and total norepinephrine exposure (p=0.0991). There was a difference approaching significance seen in initiation of additional vasopressors where epinephrine was more likely to be started in the morbidly obese group (p=0.0515). Conclusions: Evaluation of patients receiving weight-based norepinephrine of septic shock did not result in a statistical difference between the three BMI classes in the incidence of tachycardia.
Valencia et al. (Sun,) studied this question.