Background: Guidelines recommend arginine vasopressin (AVP) at a fixed dose for patients with septic shock who remain hypotensive after fluid resuscitation and norepinephrine, regardless of body weight. Objective: This study seeks to evaluate whether body weight affects hemodynamic response (HDR) to AVP in critically ill patients with septic shock. Methods: This was a single-center, retrospective cohort study of adult patients with septic shock. Patients received AVP at a fixed rate of 0.03 units/min in addition to catecholamine vasopressors and were grouped into 4 categories according to admission body weight. The primary endpoint was the time from AVP initiation to HDR, defined as a decrease in norepinephrine equivalents (NEEs) by at least 0.03 mcg/kg/min while maintaining a mean arterial pressure of at least 65 mm Hg for 1 hour. Secondary endpoints included a time to HDR defined as reduction in NEE of 0.05 mcg/kg/min, intensive care unit (ICU) length of stay (LOS), total duration of vasoactive agents, incidence of renal replacement therapy (RRT), and 28-day mortality. Results: A total of 170 patients were included in the study. No differences were observed between categories in time to HDR of 0.03 NEE ( P = 0.854) or 0.05 NEE ( P = 0.985). The total duration of vasopressors and ICU LOS were also similar between categories ( P > 0.05). Patients weighing <75 kg had a lower incidence of RRT ( P < 0.001) and patients weighing <100 kg had a lower 28-day mortality ( P = 0.006). These findings remained significant after regression analysis. Conclusion and Relevance: Although body weight did not have a significant impact on the time to HDR, there was a significant difference in the incidence of RRT and 28-day mortality favoring those who weighed <75 and <100 kg, respectively. These findings contribute to the existing body of evidence, though larger trials are warranted to assess this further.
Jorgensen et al. (Mon,) studied this question.