Norepinephrine dosage: the details go beyond a grain of salt

Norepinephrine Salt Formulations and Risk of Therapeutic Error: Results of a National Survey

OBJECTIVES

Norepinephrine is available commercially in solution containing its salt (eg, tartrate), but only the base form (ie, norepinephrine base) is active pharmacologically. Unfortunately, the outer label of drug packages frequently reports the dosage of norepinephrine as a salt, which can lead potentially to therapeutic errors when prescribing norepinephrine. We performed a survey to assess the level of awareness of this issue.

DESIGN

National survey.

SETTING

Acute care units of Italian hospitals.

PARTICIPANTS

Acute care physicians and nurses.

INTERVENTIONS

A 15-item online survey was emailed to 305 critical care practitioners in Italy. Questions included information on the participants' background, methods of diluting norepinephrine, interpretation of recommended doses from guidelines, and a sample case related to the preparation and administration of the drug.

MEASUREMENTS AND MAIN RESULTS

We collected 106 responses from 54 hospitals. All hospitals used norepinephrine bitartrate salt. Of the participants, 53% responded that the guidelines express norepinephrine dosages as a salt, 23% as the base form, and 24% were unsure or unaware about it. The simulated patient-dose calculation was resolved in 81% of cases with an incorrect calculation referring to the norepinephrine salt and only in 19% referring to the norepinephrine base.

CONCLUSIONS

There is significant variability in dosage management of norepinephrine across different hospital units, as well as a lack of knowledge regarding the salt-to-base ratio. Scientific publications (eg, guidelines) should specify whether they are referring to the base or salt form of norepinephrine. The adoption of different labeling and national standards for dilution may decrease the risk of therapeutic errors.

The impact of norepinephrine dose reporting heterogeneity on mortality prediction in septic shock patients

BACKGROUND

Norepinephrine (NE) is a cornerstone drug in the management of septic shock, with its dose being used clinically as a marker of disease severity and as mortality predictor. However, variations in NE dose reporting either as salt formulations or base molecule may lead to misinterpretation of mortality risks and hinder the process of care.

METHODS

We conducted a retrospective analysis of the MIMIC-IV database to assess the impact of NE dose reporting heterogeneity on mortality prediction in a cohort of septic shock patients. NE doses were converted from the base molecule to equivalent salt doses, and their ability to predict 28-day mortality at common severity dose cut-offs was compared.

RESULTS

4086 eligible patients with septic shock were identified, with a median age of 68 [57-78] years, an admission SOFA score of 7 [6-10], and lactate at diagnosis of 3.2 [2.4-5.1] mmol/L. Median peak NE dose at day 1 was 0.24 [0.12-0.42] μg/kg/min, with a 28-day mortality of 39.3%. The NE dose showed significant heterogeneity in mortality prediction depending on which formulation was reported, with doses reported as bitartrate and tartrate presenting 65 (95% CI 79-43)% and 67 (95% CI 80-47)% lower ORs than base molecule, respectively. This divergence in prediction widened at increasing NE doses. When using a 1 μg/kg/min threshold, predicted mortality was 54 (95% CI 52-56)% and 83 (95% CI 80-87)% for tartrate formulation and base molecule, respectively.

CONCLUSIONS

Heterogeneous reporting of NE doses significantly affects mortality prediction in septic shock. Standardizing NE dose reporting as base molecule could enhance risk stratification and improve processes of care. These findings underscore the importance of consistent NE dose reporting practices in critical care settings.

A common data model for the standardization of intensive care unit medication features

Objective

Common data models provide a standard means of describing data for artificial intelligence (AI) applications, but this process has never been undertaken for medications used in the intensive care unit (ICU). We sought to develop a common data model (CDM) for ICU medications to standardize the medication features needed to support future ICU AI efforts.

Materials and Methods

A 9-member, multi-professional team of ICU clinicians and AI experts conducted a 5-round modified Delphi process employing conference calls, web-based communication, and electronic surveys to define the most important medication features for AI efforts. Candidate ICU medication features were generated through group discussion and then independently scored by each team member based on relevance to ICU clinical decision-making and feasibility for collection and coding. A key consideration was to ensure the final ontology both distinguished unique medications and met Findable, Accessible, Interoperable, and Reusable (FAIR) guiding principles.

Results

Using a list of 889 ICU medications, the team initially generated 106 different medication features, and 71 were ranked as being core features for the CDM. Through this process, 106 medication features were assigned to 2 key feature domains: drug product-related (n = 43) and clinical practice-related (n = 63). Each feature included a standardized definition and suggested response values housed in the electronic data library. This CDM for ICU medications is available online.

Conclusion

The CDM for ICU medications represents an important first step for the research community focused on exploring how AI can improve patient outcomes and will require ongoing engagement and refinement.

Position Paper on the Reporting of Norepinephrine Formulations in Critical Care from the Society of Critical Care Medicine and European Society of Intensive Care Medicine Joint Task Force

OBJECTIVES

To provide guidance on the reporting of norepinephrine formulation labeling, reporting in publications, and use in clinical practice.

DESIGN

Review and task force position statements with necessary guidance.

SETTING

A series of group conference calls were conducted from August 2023 to October 2023, along with a review of the available evidence and scope of the problem.

SUBJECTS

A task force of multinational and multidisciplinary critical care experts assembled by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

INTERVENTIONS

The implications of a variation in norepinephrine labeled as conjugated salt (i.e., bitartrate or tartrate) or base drug in terms of effective concentration of norepinephrine were examined, and guidance was provided.

MEASUREMENTS AND MAIN RESULTS

There were significant implications for clinical care, dose calculations for enrollment in clinical trials, and results of datasets reporting maximal norepinephrine equivalents. These differences were especially important in the setting of collaborative efforts across countries with reported differences.

CONCLUSIONS

A joint task force position statement was created outlining the scope of norepinephrine-dose formulation variations, and implications for research, patient safety, and clinical care. The task force advocated for a uniform norepinephrine-base formulation for global use, and offered advice aimed at appropriate stakeholders.