Signa Vitae. 2023; 19(6): 224-226. doi: 10.22514/sv.2023.036
Letter to the Editor

A shortcut for preparing doses of positive inotropic drug infusions in emergency patient management—”fast inotrope bag (FiB) coefficient”

Suleyman Alpar1, Sarper Yilmaz2,*,, Rohat Ak2

1Faculty of Medicine, Beykent University, 34500 Istanbul, Turkey

2Department of Emergency Medicine, Kartal Dr. Lutfi Kirdar City Hospital, University of Health Sciences, 34865 Istanbul, Turkey

*Corresponding Author(s):sarperyilmaz08@gmail.com (Sarper Yilmaz)

History Submitted: 21 November 2022 | Accepted: 24 February 2023 | Published: 08 November 2023
Copyright:  ©2023  The Author(s). Published by MRE Press.
This is an open access article under the CC BY 4.0 license (https://creativecommons.org/licenses/by/4.0/).

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Abstract

The most basic rule for the management of patients in the emergency departments (EDs) and critical & intensive units (ICUs) are quick decision and quick order medication. For this reason, calculator applications are a necessary part of EDs in order to calculate some drug doses quickly. With the simple formula we discovered, it will be much easier to place an order for the 4 most frequently used drugs of the EDs (dopamine, dobutamine, norepinephrine, epinephrine). We recommend this simple and fast calculation method to all EDs and ICUs with fast inotrope bag (FiB) coefficient. This coefficient has been developed especially for simple pump devices or dosing devices that do not use ready-made inotropic drug bags and that, if needed, first control the preparation of the solution and then the hourly infusion of the prepared solution. These devices are used only because the amount of solution to be given to the patient per hour can be monitored. Taking advantage of this coefficient, the inotrope needed by the patient can be administered easily and quickly with only the patient’s weight information, and the initial dose corresponds to the dose range recommended by the guidelines for inotropes.

Keywords:Inotrope bags;Dopamine;Dobutamine;Norepinephrine;Epinephrine;Coefficient
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Cite this article

Suleyman Alpar, Sarper Yilmaz, Rohat Ak. A shortcut for preparing doses of positive inotropic drug infusions in emergency patient management—"fast inotrope bag (FiB) coefficient''. Signa Vitae. 2023; 19(6): 224-226. doi: 10.22514/sv.2023.036

Dear Editor,

The inotrope agents dopamine, dobutamine, norepinephrine, and epinephrine are among the most commonly used drugs in critically ill patients in the prehospital emergency care, emergency departments (EDs) and critical & intensive units (ICUs). When starting inotropic therapy in these acute care areas that necessitate urgent intervention, administration doses and forms of drugs should be formulated in the simplest way possible. These inotropic treatments are generally hard to order, taking into account complex formulas and multiple calculations for initial administration doses.

As far as the utilization of powerful inotrope dopamine, The American Heart Association (AHA) has provided the following formula: Multiply 6 times the weight in kg times the desired dose in µg/kg/min, divided by the desired amount of fluid to infuse in mL/h which produces the amount of dopamine in mg to add to each 100 mL solution prepared) [1, 2]. In a survey conducted on this issue, only 4 out of 50 physicians were able to bring this formula into practice correctly [3]. The remaining ones used calculation methods they had developed themselves.

Since the calculations of norepinephrine and epinephrine dosages are similarly challenging, we have devised a formula in mL/h for more rapid applicability and simplification of the initial doses of all these inotropes [4, 5]. While deriving this formula, the amount of drugs were taken into consideration as available in vials in hospital EDs and ICUs and prehospital emergency care in Turkey. In the derived formula, the initial infusion rate can be conceived for all four inotropes via the same method (Table 1).

Table 1.Calculation of initial infusion rate in solutions prepared with “FiB Coefficient” for dopamine, noradrenaline, adrenaline, and doputamine [2, 3, 4, 5].
Positive inotropeDose in guidelinesAmount of positive inotrope in a standard vialPreparation of the solutionsCalculation of initial infusion rateInitial infusion rate
Dopamine5–20 mcg/kg/min200 mg/5 mL100 mL normal saline or 5% water in dextrose + 1 vial NA/DA/EPI/DBABody weight ×0.15* (mL/hr)5 mcg/kg/min
Noradrenaline0.05–0.15 mcg/kg/min4 mg/4 mL0.1 mcg/kg/min
Epinephrine0.01–0.5 mcg/kg/min1 mg–1/10000.025 mcg/kg/min
Dobutamine2–5 mcg/kg/min250 mg/20 mL5 mcg/kg/min
* FiB Coefficient: 0.15, NA: noradrenaline, DA: dopamine, EPI: adrenaline, DBA: dobutamine.

When the Fast inotrope bag (FiB) Coefficient is multiplied by the patient weight (kg), the initial rate of the prepared standard solution is produced. In this way, the clinician is able to initiate treatment with a single formula for the initial dose of these three agents. Another advantage of this approach is that the calculation can be performed in a standard fashion in each of these four inotropic agents.

The advantages of this formula are its easy computability, no need for additional mathematical operations at any stage, starting the treatment by applying the same coefficient for all four inotropes, and calculating the result in mL/hour, which has been readily accustomed by a majority of healthcare personnel. At the same time, the infusion dose can be modified with a simple calculation, even if the amount of fluid in which the drug is administered changes. For example, if we use a bottle of 500 mL (instead of 100 mL taken in the standard formula), the infusion rate can be adjusted by multiplying the result in the formula by 5.

We know that the value of our formula is limited by the widespread availability in many countries of pre-mixed inotrope bags and smart infusion pumps that do the involved math.

When we consider all the EDs of the world, disaster conditions and EDs managed with limited facilities, we think that our formula will be used very frequently and will contribute to both emergency medicine and intensive care literature.

This coefficient will not only enable physicians to calculate the preparation rate of inotrope bags, but also will enable nurses preparing inotropic bags to check whether the inotropic bag orders given are in the appropriate dose range or will enable paramedics to initiate inotropes easily and practically for patients who may need inotropes in the prehospital period. Preparation examples for different age and weight groups are given in Table 2. The following two important notes should be kept in mind by anyone using this formula:

Note 1: Calculated initial doses are recommended starting doses for patients in need of inotropes. “Standard” doses of each drug differ in various clinical situations.

Note 2: The doses calculated by the formula are within the recommended ranges for the beginning, and doses can be adjusted up and down in accord with the given clinical situation.

Table 2.Calculation of initial infusion rate in sample populations [2, 3, 4, 5].
Positive inotrope dose in guidelines (mcg/kg/min)PopulationsMean weightPreparation of inotropic bagInitial infusion rate (mL/hour)
DA: 5.00–20.00 NA: 0.05–0.15 EPI: 0.01–0.50 DBA: 2.00–5.00Infant5 kg100 mL normal saline or 5% water in dextrose + 1 vial NA/DA/EPI/DBA5 × 0.15 = 0.75
Toddler10 kg10 × 0.15 = 1.50
Child20 kg20 × 0.15 = 3.00
Adult70 kg70 × 0.15 = 10.50
Adult100 kg100 × 0.15 = 15.00
NA: noradrenaline, DA: dopamine, EPI: adrenaline, DBA: dobutamine.

Availability of data and materials

The data presented in this study are available on reasonable request from the corresponding author.

Author contributions

SA, SY and RA—conceived the study, designed the trial; supervised the conduct of the trial and data collection; takes responsibility for the paper as a whole; undertook recruitment managed the data, including quality control; drafted the manuscript. All authors contributed substantially to its revision.

Ethics approval and consent to participate

Not applicable.

Acknowledgment

Thanks to all the peer reviewers and Ali Cankut Tatliparmak for their opinions and suggestions and for their support of this research.

Funding

This research received no external funding.

Conflict of interest

The authors declare no conflict of interest.

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