Low-concentration norepinephrine in the French operating theatre: A study of daily practices and pharmacological dosages in real-life conditions.

Abstract

Background: Traditionally, ephedrine and phenylephrine have been used to maintain blood pressure during anaesthesia. The use of low-concentration norepinephrine ('baby norepinephrine', bNOR) appears to be increasing.

Objectives: To better define the current role of norepinephrine in the management of intra-operative hypotension and to identify the challenges associated with its use.

Design: A practice survey (including collection of vasopressor usage data and a questionnaire on the use of bNOR in French operating rooms), combined with pharmacological assessments of norepinephrine dilutions.

Setting: Vasopressor usage data were collected between 2017 and 2022 in 21 French hospitals. The survey was conducted from July 2021 to April 2022 among anaesthesia personnel within the French-speaking community. Pharmacological analyses were performed in two French university hospitals.

Patients: None.

Intervention: None.

Main outcome measures: To assess vasopressor use in operating theatres in France, and to evaluate the accuracy and stability of manually prepared bNOR dilutions.

Results: Usage data demonstrated an increase in norepinephrine use from 28 518 to 59 598 vials (+92.4%), whereas phenylephrine use decreased over the same period from 49 407 vials and prefilled syringes to 14 252 (-71.1%). Survey findings indicated that a majority of respondents (72.5%) use bNOR diluted to concentrations of 10 and 16 μg ml^-1. The principal barrier to routine use identified was the risk of dilution inaccuracy. Norepinephrine concentrations were then measured in 16 samples of 10 μg ml^-1 and 50 samples of 5 μg ml^-1 manually prepared bNOR. Median concentration errors were 10.8% (± 1.34 μg ml^-1) for 10 μg ml^-1 dilutions and 13.4% (± 0.54 μg ml^-1) for 5 μg ml^-1 dilutions. Stability testing revealed a reduction in norepinephrine concentration of up to 32% over 24 h.

Conclusion: bNOR is emerging as a standard approach for the management of intra-operative hypotension in French operating theatres. However, dilution inaccuracies and stability limitations highlight the need for ready-to-use formulations in order to reduce errors and improve peri-operative care.