The effects of vasopressin on hemodynamics and renal function in severe septic shock: a case series.

OBJECTIVE: To review all cases of septic shock treated with vasopressin to determine the effects on hemodynamic and renal function and to document any adverse effects.

SETTING: A 14-bed mixed medical-surgical ICU of St. Paul's Hospital, a 450-bed tertiary referral hospital affiliated with the University of British Columbia.

PATIENTS: All ICU patients who received vasopressin for treatment of severe septic shock between August 5, 1997, and March 21, 1999.

RESULTS: We identified 50 patients: age 60 (+/-14); APACHE II score 27 (+/-7). Baseline data (T0) was compared to data at T4, T24 and T48 (4, 24 and 48 h) on infusion. Mean arterial pressure (MAP) increased by 18% from T0 to T4 and remained stable at T24 (p=0.006) and T48 (p=0.008). Systolic pulmonary artery pressure (PAP) was unchanged at 45+/-13 mmHg. Mean cardiac index (CI) decreased by 11% at T4 (p=0.03). Urine output increased 79% at T4 (p=0.005) and further increases were not significant at T24 and T48. Mean pressor dosage decreased by 33% at T4 (p=0.001), by 53% at T24 (p=0.002) and by 48% at T48 (p=0.01). Hospital mortality was 85%. There were six cardiac arrests; all but one occurred at a vasopressin dose of 0.05 U/min or more.

CONCLUSIONS: In this group of patients with severe septic shock, vasopressin infusion increased MAP and urine output and decreased catecholamine requirements. Doses higher than 0.04 U/min were not associated with increased effectiveness and may have been associated with higher adverse effects.