- Email: [email protected]
Rapid Dosing of Critical Care Infusions: The Dopamine and Norepinephrine “Clocks”
PHARM/TOX CORNER
RAPID DOSING OF CRITICAL CARE INFUSIONS: THE DOPAMINE AND NOREPINEPHRINE “CLOCKS” Authors: Robert V. DiGregorio, PharmD, and Horatio B. Fung, PharmD, BCPS, Brooklyn and Bronx, NY Section Editor: Allison A. Muller, PharmD, D.ABAT
Earn Up to 7 CE Hours. See page 175.
M
edication errors can occur at any point throughout the course of drug therapy. Errors are commonly made in drug prescribing, dispensing, administering, or monitoring. According to published data, the majority of errors that lead to patient harm come from the administration process.1 Errors made in the administration of intravenous medications are particularly troubling, because systemic absorption of the medication into the patient is virtually instantaneous and the ability to prevent the effects of such an error is often limited. Over the past few years, much attention has been paid to reducing errors of high-risk medications, including many emergency and critical care infusions. Organizations such as the Institute of Medicine,2 The Joint Commission,3 and The Institute for Safe Medication Practices4 have advocated for standardized concentrations of intravenous medications and the use of technology with decision support, including “smart” pumps, to prevent dosing errors. Published data on the use of smart pumps show that although smart pump implementation identified errors, the rate of errors did not change.5,6 If not dosed correctly, infused medications, such as dopamine, norepinephrine, and lidocaine, can lead to grave consequences. A dosing scheme for lidocaine, known as the “lidocaine clock” has been taught in Advanced Cardiac Life Support and paramedic training courses for many years. Robert V. DiGregorio is Professor of Pharmacy Practice, Arnold & Marie Schwartz College of Pharmacy & Health Sciences, Long Island University, and Director of Pharmacotherapy Services, The Brooklyn Hospital Center, Brooklyn, NY. Horatio B. Fung, is Clinical Pharmacy Specialist, Medicine/Surgical Patient Care Center, James J. Peters Veterans Affairs Medical Center, Bronx, NY. For correspondence, write: Robert DiGregorio, PharmD, 73 County Courthouse Rd, Garden City Park, NY 11040-5222; E-mail: Robert.DiGregorio@ liu.edu.
Detailed information on this dosing scheme can be found on the Internet,7 although it has not been described in the medical literature. A variety of methods for dosing infusions have been described in the literature, including charts, formulas, the “key number” conversion method, and the “factor of 15” method.8-11 We have developed a “clock” method for dosing dopamine and norepinephrine and have used it for more than 15 years with great success. Despite the growing use of smart pumps,12,13 a quick, accurate, and reliable dosing tool for critical care infusions serves as a valuable method of providing safe medication dosing and administration without delay. We believe that others may benefit from these clocks and will use them to enhance patient safety in the chaotic environment of the emergency department, in the ICU, and in the prehospital care setting. The dopamine and norepinephrine clocks rely on the use of standardized medication concentrations and are described in this article. Norepinephrine
To use the norepinephrine clock, an intravenous norepinephrine solution is prepared by adding 2 mg of norepinephrine to 500 mL of 5% dextrose in water (D5W) or normal saline (NS). Like lidocaine, norepinephrine is not dosed based on body weight; therefore the clock simply works by finding the dose desired and the corresponding “minute hand” of the clock. The minute hand translates the dose to infusion rate in milliliters per hour (Figure 1). Dopamine
doi: 10.1016/j.jen.2008.07.019
Dopamine dosing is based on patient weight and the desired pharmacologic effect. Dosing and administration are complex. In addition, converting micrograms per kilogram per minute to milliliters per hour is time-consuming and a frequent source of errors. An example of such an error has been reported in the August 2007 issue of a newsletter published by The Institute for Safe Medication Practices.4 To use the dopamine clock, an intravenous dopamine solution is prepared by adding 400 mg of dopamine to
March 2009 35:2
JOURNAL OF EMERGENCY NURSING
J Emerg Nurs 2009;35:165-8. 0099-1767/$36.00 Copyright © 2009 published by Elsevier Inc on behalf of the Emergency Nurses Association.
165
PHARM/TOX CORNER/DiGregorio and Fung
FIGURE 1 Norepinephrine dosing clock.
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35:2 March 2009
PHARM/TOX CORNER/DiGregorio and Fung
FIGURE 2 Dopamine dosing clock.
March 2009 35:2
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500 mL of D5W or NS. Dopamine is dosed based on body weight and is infused in micrograms per kilogram per minute. The clock works by finding the “hour” that approximately corresponds to the patient’s body weight. The body weight is found around the outer perimeter of the clock, with 40-kg increments every 3 hours. If a patient’s exact weight is known, it can be transferred to the clock, near the closest hour; thus a 60-kg patient would correspond to 4:30, and a 70-kg patient would correspond to 5:15. Because the weight of most patients in the emergency setting either is not known or may fluctuate based on volume status, the weight can be approximated and rounded to the nearest hour. The dose is typically titrated; thus a precise starting dose based on weight is not clinically significant. The designated hour represents the infusion rate in milliliters per hour that delivers dopamine at 1 μg · kg−1 · min−1. Multiplying the hour, or multiplier, by the desired dose will give the desired infusion rate in milliliters per hour (Figure 2). Conclusion
The emergency clocks are useful tools for use in settings where orders of critical care drugs are often written in micrograms per kilogram per minute or require frequent titration by fixed increments. The clocks described not only facilitate these conversions but also provide simple references for checking the appropriateness and accuracy of doses. It is important to remember to select the right clock for the right drug and not to interchange the clocks. It is also important to note that each clock only works for the standard concentrations specified. The purpose of introducing the various clocks is to provide an alternative method that will reduce the possibility of errors and the time involved in calculating infusions commonly used in the critical care and emergency setting. Acknowledgment
2. Institute of Medicine. Aspden JA, Wolcott J, Bootman L, Cronenwett LR, eds. Preventing medication errors: quality chasm series. Washington, DC: National Academy of Sciences; 2006. p. 256. 3. The Joint Commission. 2008 National Patient Safety Goals, Hospital Program. Available at: http://www.jointcommission.org/ PatientSafety/NationalPatientSafetyGoals/08_hap_npsgs.htm. Accessed November 23, 2007. 4. The Institute for Safe Medication Practices. Lack of standard dosing methods contributes to IV errors. Available at: http:// www.ismp.org/Newsletters/acutecare/articles/20070823.asp. Accessed November 23, 2007. 5. Rothschild JM, Keohane CA, Cook EF, Orav EJ, Burdick E, Thomson S, et al. A controlled trial of smart infusion pumps to improve medication safety in critically ill patients. Crit Care Med 2005;33:533-40. 6. Adachi W, Lodolce AE. Use of failure mode and effects analysis in improving the safety of i.v. drug administration. Am J Health Syst Pharm 2005;62:917-20. 7. Spitler KR. IV and drug calculations for busy paramedics. Available at: http://www.gaems.net/download/drugcalc.pdf. Accessed November 23, 2007. 8. Rosenthal KA. Chart vs. formula method. Dimens Crit Care Nurs 1982;1:326-31. 9. Keenan PA. The “key number” conversion method. Dimens Crit Care Nurs 1982;1:332-3. 10. DeAngelis R, Brott WH. The “factor of 15” method. Dimens Crit Care Nurs 1982;1:334-7. 11. Carey BE. Microdrop calculation for neonates. Dimens Crit Care Nurs 1982;1:338-9. 12. Pedersen CA, Schneider PJ, Scheckelhoff DJ. ASHP national survey of pharmacy practice in hospital settings: dispensing and administration—2002. Am J Health Syst Pharm 2003;60:52-65. 13. Pedersen CA, Schneider PJ, Scheckelhoff DJ. ASHP national survey of pharmacy practice in hospital settings: dispensing and administration—2005. Am J Health Syst Pharm 2006;63: 327-45.
We acknowledge Kathleen Catania, RN, for her review of this article.
REFERENCES 1. Leape LL, Bates DW, Cullen DJ, Cooper J, Demonaco T, Gallivan R, et al. Systems analysis of adverse drug events. ADE Prevention Study Group. JAMA 1995;274:35-43.
168
Submissions to this column are encouraged and may be sent to Allison A. Muller, PharmD, D.ABAT [email protected]
JOURNAL OF EMERGENCY NURSING
35:2 March 2009
RAPID DOSING OF CRITICAL CARE INFUSIONS: THE DOPAMINE AND NOREPINEPHRINE “CLOCKS” Authors: Robert V. DiGregorio, PharmD, and Horatio B. Fung, PharmD, BCPS, Brooklyn and Bronx, NY Section Editor: Allison A. Muller, PharmD, D.ABAT
Earn Up to 7 CE Hours. See page 175.
M
edication errors can occur at any point throughout the course of drug therapy. Errors are commonly made in drug prescribing, dispensing, administering, or monitoring. According to published data, the majority of errors that lead to patient harm come from the administration process.1 Errors made in the administration of intravenous medications are particularly troubling, because systemic absorption of the medication into the patient is virtually instantaneous and the ability to prevent the effects of such an error is often limited. Over the past few years, much attention has been paid to reducing errors of high-risk medications, including many emergency and critical care infusions. Organizations such as the Institute of Medicine,2 The Joint Commission,3 and The Institute for Safe Medication Practices4 have advocated for standardized concentrations of intravenous medications and the use of technology with decision support, including “smart” pumps, to prevent dosing errors. Published data on the use of smart pumps show that although smart pump implementation identified errors, the rate of errors did not change.5,6 If not dosed correctly, infused medications, such as dopamine, norepinephrine, and lidocaine, can lead to grave consequences. A dosing scheme for lidocaine, known as the “lidocaine clock” has been taught in Advanced Cardiac Life Support and paramedic training courses for many years. Robert V. DiGregorio is Professor of Pharmacy Practice, Arnold & Marie Schwartz College of Pharmacy & Health Sciences, Long Island University, and Director of Pharmacotherapy Services, The Brooklyn Hospital Center, Brooklyn, NY. Horatio B. Fung, is Clinical Pharmacy Specialist, Medicine/Surgical Patient Care Center, James J. Peters Veterans Affairs Medical Center, Bronx, NY. For correspondence, write: Robert DiGregorio, PharmD, 73 County Courthouse Rd, Garden City Park, NY 11040-5222; E-mail: Robert.DiGregorio@ liu.edu.
Detailed information on this dosing scheme can be found on the Internet,7 although it has not been described in the medical literature. A variety of methods for dosing infusions have been described in the literature, including charts, formulas, the “key number” conversion method, and the “factor of 15” method.8-11 We have developed a “clock” method for dosing dopamine and norepinephrine and have used it for more than 15 years with great success. Despite the growing use of smart pumps,12,13 a quick, accurate, and reliable dosing tool for critical care infusions serves as a valuable method of providing safe medication dosing and administration without delay. We believe that others may benefit from these clocks and will use them to enhance patient safety in the chaotic environment of the emergency department, in the ICU, and in the prehospital care setting. The dopamine and norepinephrine clocks rely on the use of standardized medication concentrations and are described in this article. Norepinephrine
To use the norepinephrine clock, an intravenous norepinephrine solution is prepared by adding 2 mg of norepinephrine to 500 mL of 5% dextrose in water (D5W) or normal saline (NS). Like lidocaine, norepinephrine is not dosed based on body weight; therefore the clock simply works by finding the dose desired and the corresponding “minute hand” of the clock. The minute hand translates the dose to infusion rate in milliliters per hour (Figure 1). Dopamine
doi: 10.1016/j.jen.2008.07.019
Dopamine dosing is based on patient weight and the desired pharmacologic effect. Dosing and administration are complex. In addition, converting micrograms per kilogram per minute to milliliters per hour is time-consuming and a frequent source of errors. An example of such an error has been reported in the August 2007 issue of a newsletter published by The Institute for Safe Medication Practices.4 To use the dopamine clock, an intravenous dopamine solution is prepared by adding 400 mg of dopamine to
March 2009 35:2
JOURNAL OF EMERGENCY NURSING
J Emerg Nurs 2009;35:165-8. 0099-1767/$36.00 Copyright © 2009 published by Elsevier Inc on behalf of the Emergency Nurses Association.
165
PHARM/TOX CORNER/DiGregorio and Fung
FIGURE 1 Norepinephrine dosing clock.
166
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35:2 March 2009
PHARM/TOX CORNER/DiGregorio and Fung
FIGURE 2 Dopamine dosing clock.
March 2009 35:2
JOURNAL OF EMERGENCY NURSING
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PHARM/TOX CORNER/DiGregorio and Fung
500 mL of D5W or NS. Dopamine is dosed based on body weight and is infused in micrograms per kilogram per minute. The clock works by finding the “hour” that approximately corresponds to the patient’s body weight. The body weight is found around the outer perimeter of the clock, with 40-kg increments every 3 hours. If a patient’s exact weight is known, it can be transferred to the clock, near the closest hour; thus a 60-kg patient would correspond to 4:30, and a 70-kg patient would correspond to 5:15. Because the weight of most patients in the emergency setting either is not known or may fluctuate based on volume status, the weight can be approximated and rounded to the nearest hour. The dose is typically titrated; thus a precise starting dose based on weight is not clinically significant. The designated hour represents the infusion rate in milliliters per hour that delivers dopamine at 1 μg · kg−1 · min−1. Multiplying the hour, or multiplier, by the desired dose will give the desired infusion rate in milliliters per hour (Figure 2). Conclusion
The emergency clocks are useful tools for use in settings where orders of critical care drugs are often written in micrograms per kilogram per minute or require frequent titration by fixed increments. The clocks described not only facilitate these conversions but also provide simple references for checking the appropriateness and accuracy of doses. It is important to remember to select the right clock for the right drug and not to interchange the clocks. It is also important to note that each clock only works for the standard concentrations specified. The purpose of introducing the various clocks is to provide an alternative method that will reduce the possibility of errors and the time involved in calculating infusions commonly used in the critical care and emergency setting. Acknowledgment
2. Institute of Medicine. Aspden JA, Wolcott J, Bootman L, Cronenwett LR, eds. Preventing medication errors: quality chasm series. Washington, DC: National Academy of Sciences; 2006. p. 256. 3. The Joint Commission. 2008 National Patient Safety Goals, Hospital Program. Available at: http://www.jointcommission.org/ PatientSafety/NationalPatientSafetyGoals/08_hap_npsgs.htm. Accessed November 23, 2007. 4. The Institute for Safe Medication Practices. Lack of standard dosing methods contributes to IV errors. Available at: http:// www.ismp.org/Newsletters/acutecare/articles/20070823.asp. Accessed November 23, 2007. 5. Rothschild JM, Keohane CA, Cook EF, Orav EJ, Burdick E, Thomson S, et al. A controlled trial of smart infusion pumps to improve medication safety in critically ill patients. Crit Care Med 2005;33:533-40. 6. Adachi W, Lodolce AE. Use of failure mode and effects analysis in improving the safety of i.v. drug administration. Am J Health Syst Pharm 2005;62:917-20. 7. Spitler KR. IV and drug calculations for busy paramedics. Available at: http://www.gaems.net/download/drugcalc.pdf. Accessed November 23, 2007. 8. Rosenthal KA. Chart vs. formula method. Dimens Crit Care Nurs 1982;1:326-31. 9. Keenan PA. The “key number” conversion method. Dimens Crit Care Nurs 1982;1:332-3. 10. DeAngelis R, Brott WH. The “factor of 15” method. Dimens Crit Care Nurs 1982;1:334-7. 11. Carey BE. Microdrop calculation for neonates. Dimens Crit Care Nurs 1982;1:338-9. 12. Pedersen CA, Schneider PJ, Scheckelhoff DJ. ASHP national survey of pharmacy practice in hospital settings: dispensing and administration—2002. Am J Health Syst Pharm 2003;60:52-65. 13. Pedersen CA, Schneider PJ, Scheckelhoff DJ. ASHP national survey of pharmacy practice in hospital settings: dispensing and administration—2005. Am J Health Syst Pharm 2006;63: 327-45.
We acknowledge Kathleen Catania, RN, for her review of this article.
REFERENCES 1. Leape LL, Bates DW, Cullen DJ, Cooper J, Demonaco T, Gallivan R, et al. Systems analysis of adverse drug events. ADE Prevention Study Group. JAMA 1995;274:35-43.
168
Submissions to this column are encouraged and may be sent to Allison A. Muller, PharmD, D.ABAT [email protected]
JOURNAL OF EMERGENCY NURSING
35:2 March 2009