Effect of Body Weight on Hemodynamic Response to Vasopressin in Patients With Septic Shock

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.

This study seeks to evaluate whether body weight affects hemodynamic response (HDR) to AVP in critically ill patients with septic shock.

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.

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.

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.