Q: What is the dose of Hydroxocobalamin in vasoplegia unresponsive to pressors?
Answer: 5 gram over 10 minutes
Hydroxocobalamin is a form of vitamin B12 and is highly bioavailable. It is considered better than methylene blue in resistant vasoplegia as it works via a dual mechanism.
1. By inhibiting nitric oxide (NO) synthase in vascular endothelial cells, causing decrease NO release and increased systemic vascular resistance (SVR)
2. Hydroxocobalamin binds to hydrogen sulfide (H2S) which is found to cause vascular dilatation.
In ICU, it should be kept in mind that hydroxocobalamin may also falsely increase hematocrit and pulse oximetry value.
The dose is 5 gram over 10 minutes and can be repeated once.
1. Cai Y, Mack A, Ladlie BL, Martin AK. The use of intravenous hydroxocobalamin as a rescue in methylene blue-resistant vasoplegic syndrome in cardiac surgery. Ann Card Anaesth. 2017;20(4):462-464. doi:10.4103/aca.ACA_88_17
2. Hessel EA 2nd. What's New in Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2019; 33:2296.