Friday, May 12, 2006

vasopressin/norepinephrine ratio

Friday May 12, 2006
vasopressin/norepinephrine ratio in septic shock

Role of vasopressin in septic shock seems promising but we don't have enough data yet to support its regular use. Interesting study in Taiwan was done by Lin and co. and published 6 months ago in Am J Emerg Med. 182 patients (consecutive patients visiting the emergency department), who met the inclusive criteria were divided into 3 groups (per standard guidelines):

  • septic shock,
  • severe sepsis, and
  • sepsis.

30 healthy subjects were included as control.

The plasma vasopressin level at baseline was drawn early in course in emergency department. The plasma vasopressin level was significantly lower for those who finally developed septic shock (3.6 +/- 2.5 pg/mL) than severe sepsis (21.8 +/- 4.1 pg/mL) and sepsis group (10.6 +/- 6.5 pg/mL) - kind of bell curve.

Simultaneouly norepinephrine level was measured in the same groups. Norepinephrine level was highest for septic shock group, (3650 +/- 980 pg/mL) in comparion to severe sepsis (3600 +/- 1000 pg/mL) and sepsis group (1720 +/- 320 pg/mL).

The vasopressin/norepinephrine ratio (very early in the course) was significantly lower for the patients with final diagnosis of septic shock (P less than .001).

This study lead us to logical question: Should we use vasopressin early in septic shock instead later ? but probably it is still early to jump on vasopressin, atleast till we get results from evidence based studies such as pending VASST (Vasopressin Vs. Norepinephrine in Septic Shock) study.

*VASST is an ongoing multi-centre triple-blind randomized controlled trial being conducted in Canada and Australia to determine the effectiveness of Vasopressin compared to Norepinephrine (28-day and 90-day survival).

Previous related pearl:
Vasopressin .07 units/min ?

Reference: (click to get abstract)
Low plasma vasopressin/norepinephrine ratio predicts septic shock. Am J Emerg Med. 2005 Oct;23(6):718-24.