# Hydroxocobalamin for the treatment of vasoplegia after lung transplantation: A case series

## TL;DR

This case series explores the use of hydroxocobalamin to treat vasoplegia in lung transplant patients, showing some improvement in blood pressure and reduced vasopressor use.

## Contribution

The paper is the first to report hydroxocobalamin use for post-lung-transplant vasoplegia in humans.

## Key findings

- Hydroxocobalamin increased mean arterial pressure in all three patients within 2 hours.
- Patients 1 and 2 showed sustained improvements in blood pressure and reduced vasopressor use at 24 hours.
- One patient developed methemoglobinemia and elevated triglycerides as side effects.

## Abstract

The use of hydroxocobalamin following lung transplantation has not been previously reported. We present a series of 3 cases where hydroxocobalamin was used to treat postoperative vasoplegia.

We conducted a single-center, retrospective review of lung transplantation recipients from January 2016 to December 2020. We used cumulative vasopressor index to standardize vasopressor dose administered and mean arterial pressure at 2- and 24-hour time-points following hydroxocobalamin administration to assess treatment effectiveness.

We identified 3 male patients aged 49 to 62, with lung allocation scores between 89.9 and 90.6, requiring extracorporeal membrane oxygenation support (pre- and post-transplant for 5, 5, 9 and 8, 2, 2 days, respectively). Each patient received hydroxocobalamin 5,000 mg infused over 15 minutes, with patient #3 receiving an additional 6 doses over the subsequent 4 days. At the 2-hour time-point, mean arterial pressure increased in all patients (+11%, +17%, and +13%, respectively), although cumulative vasopressor indexes were inconsistent. At 24 hours, patients #1 and #2 demonstrated a marked increase in mean arterial pressure (36% and 23%, respectively) and a decrease in cumulative vasopressor index, while patient #3 displayed stable with slight reduction in cumulative vasopressor index and mean arterial pressure values. No allergic reactions were observed. Patient #3 developed methemoglobinemia and a medication-related false increase in triglycerides. All 3 patients were discharged home.

Hydroxocobalamin may be a valuable adjunct in managing refractory vasoplegia following lung transplantation.