The following is a summary of “Exploring the norepinephrine to angiotensin II conversion ratio in patients with vasodilatory hypotension: A post-hoc analysis of the ARAMIS trial,” published in the October 2023 issue of Critical Care by See et al. 

Researchers performed a retrospective study to determine the optimal conversion dose ratio from norepinephrine to angiotensin II in catecholamine-refractory vasodilatory shock patients. 

The study conducted a post-hoc analysis of the Acute Renal effects of Angiotensin II Management in Shock (ARAMIS) trial, which included vasodilatory hypotension patients. They assessed the norepinephrine equivalent dose before initiating angiotensin II and computed the conversion dose ratio between norepinephrine and angiotensin II. Subgroup analysis were conducted based on recent exposure to angiotensin receptor blockers (ARBs) and baseline renin levels. 

In 37 patients, the median conversion dose ratio between norepinephrine equivalent and angiotensin II was 10:1 for norepinephrine bitartrate (5:1 for norepinephrine base). The conversion ratio remained consistent regardless of baseline renin levels, with a median ratio of 10 (7–21) in the high renin group and 12 (5–22) in the low renin group. Notably, prior exposure to ARBs before admission was associated with a reduced conversion ratio, with a median ratio of 7 (4–13) in ARB patients compared to 12 (7–22) in non-ARB patients. 

The study found that the norepinephrine to angiotensin II conversion ratio in vasodilatory hypotension is 10:1, which can guide clinicians in using angiotensin II in critical care. 

Source: sciencedirect.com/science/article/abs/pii/S0883944123002022