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Evaluation of Vasopressin for Septic Shock in Patients on Chronic Renin-Angiotensin-Aldosterone System Inhibitors
Erwin BL, Denaburg MA, Barker AB, et al. Crit Care Med. 2017; 45: e1226-32.
Study Question: Do patients on chronic RAAS inhibitors (RAASIs) who present with septic shock have a greater response to treatment with vasopressin compared to patients not on chronic RAASI therapy?
Study Description: This was a single-center, retrospective chart review of medical and surgical patients with septic shock who received a vasopressin infusion between January 2014 and December 2015. Notable exclusion criteria were vasopressin initiation greater than 5 days after admission, vasopressin infusion duration of less than 6 hours, vasopressin rate less than 0.02 units/min or greater than 0.04 units/min, or starting a steroidal agent within 6 hours after vasopressin initiation. The primary outcome assessed was mean arterial pressure (MAP) at 6 hours (T6) after vasopressin initiation (T0). Secondary outcomes included MAP and total concomitant vasopressor requirements at different time points and ICU and hospital length of stay and mortality.
Results: Of the 596 patients who received vasopressin, 100 met inclusion criteria (37 in the chronic RAASI group and 63 in the non-RAASI group). Baseline demographics were similar between the two groups with the exception of age (older in RAASI group; 68 vs. 60 years) and prevalence of hypertension (higher in RAASI; 81 vs. 54%). There was no significant difference between the two groups in the primary outcome. MAP was not significantly different between the two groups. A lower total vasopressor requirement was observed in the RASSI group (p = 0.007).
Conclusion(s): Vasopressin was not associated with a significantly greater increase in 6-hour MAP in septic shock patients who were on chronic RAASI therapy prior to admission compared to those who were not.
Perspective: Previous studies evaluated the response to vasopressin in patients in the operative setting who were taking RAASIs, demonstrating higher MAPs, lower total vasopressor requirements, and shorter duration of hypotension. The current study is the first to assess the response to vasopressin infusion in patients with septic shock outside of the operative setting. This study has several limitations including small sample size, retrospective design, and the reliance on documentation in the medical record. Future studies may consider a prospective randomized design assessing total vasopressor requirements as the primary outcome to evaluate the effect of vasopressin.