Final Recommendation to Ensure Accurate Patient Weights

[48 Pa.B. 5679]
[Saturday, September 8, 2018]

 This document outlines final recommendations to acute care facilities in this Commonwealth regarding patient weights. The Patient Safety Authority (Authority) is responsible for submitting recommendations to the Department of Health (Department) for changes in health care practices and procedures which may be instituted for the purpose of reducing the number and severity of serious events and incidents. These recommendations were approved by both the Authority and the Department and were issued for public comment at 48 Pa.B. 4191 (July 14, 2018). The Authority did not receive any public comment.

 Having accurate patient information (for example, age, allergies, laboratory results) helps practitioners select medications, doses and routes of administration.1 One vital piece of information, the patient's weight, is especially important, because it is used to calculate the appropriate dose of a medication (for example, mg/kg, mcg/kg, mg/m2). A prescribed or dispensed medication dose can differ significantly from the appropriate dose because of missing or inaccurate patient weights.

 Patients in oncology treatment, patients with renal insufficiency, or who are elderly, pediatric or neonatal are at greater risk for adverse drug events, because they are more vulnerable to the effects of an error, and their weight may change frequently over short periods of time.2 Formulas such as the Cockcroft-Gault equation, which is used to calculate creatinine clearance to aid in the dosing of medications, and the Harris-Benedict formula, which is used to calculate basal metabolic rate, rely on knowledge of an accurate patient weight. Also, both height and weight are needed to use nomograms to determine body surface area and body mass index, for example, when calculating doses for chemotherapy.

 In the United States, most patients are weighed in pounds, both in their homes and in health care organizations. But weighing and documenting patients' weights in pounds introduces the need to convert the weight into kilograms—an error-prone process2—to conduct weight-based and other dosing. Another risk when measuring the patient's weight in pounds is failing to convert the weight into kilograms but recording that weight in kilograms (that is, documenting a weight of 200 lbs. as 200 kg instead of 90.9 kg), resulting in more than two-fold dosing errors.

 A missing or inaccurate patient weight can cause a prescribed medication dose to be significantly different from the appropriate dose and negatively impact patient outcomes.3 This problem often originates at the beginning of the patient encounter. There are times when patients arriving at hospitals may not be weighed; for example, a patient who is admitted for an emergency or is not ambulatory.2 Care units may also not be provided with appropriate scales to weigh patients, such as bed or wheelchair scales. These barriers may lead clinicians to forgo weighing a patient and decide to use a previously documented weight or estimate a patient's weight.4—7 Abundant literature exists highlighting inaccuracies of clinicians and patients or caregivers estimating patient weights and the association of these inaccuracies with medication errors, adverse events and clinical ineffectiveness.2,4,7,8

 Analysis of medication reports submitted to the Authority revealed ample evidence that health care organizations in this Commonwealth experience many of these same barriers to obtaining current, accurate patient weights. In 2010, analysis of medication errors associated with patient weights showed that more than 40% of medication reports were categorized as wrong dose/overdosage events, and 27% of all medication reports specifically mentioned mix-ups between pounds and kilograms.8 Although few events specifically mentioned that organizations were estimating weights, 27% of medication reports mentioned cases in which patients' documented weights were either higher or lower than their actual weight.

 Similar analysis was performed in 2016 to determine whether there was improvement in this area since the publication of the first Advisory. Similar to the results from 2010, the most common type of medication error was wrong dose/overdosage, representing 42% of all medication reports, and 23% of medication reports cited mix-ups between pounds and kilograms.1 Almost 40% of reports in analysis stated that patients' documented weights were inaccurate compared with their actual weights.

Final Recommendations to Ensure Accurate Patient Weights8,9

 The Authority recommends that licensed acute care facilities in this Commonwealth perform the following procedures regarding patient weights:

 1. Organizations must have processes in place to weigh each patient as soon as possible on admission, when a patient experiences a change in condition that may lead to significant changes in his weight, and during each appropriate* outpatient or emergency department encounter, with the exception of emergency situations. The use of estimated, historical or stated weight should be avoided.

 *Appropriate encounters include all encounters in which the patient is being seen by a licensed independent practitioner, excluding life-threatening situations where the delay in weighing the patient could lead to serious harm (for example, major trauma). It excludes laboratory and other services that do not prescribe or administer medications.

 2. Organizations must have a process in place to measure and document a patient's weight in metric units (for example, grams or kilograms) only. This would include computer information systems, infusion pumps and other medication devices, printouts and preprinted order forms that prompt users to record patient weight.


 • Expectation of improved quality care:

 o Accurate dosing of weight-based medications by avoiding over-doses or under-doses and subsequent harm due to toxicities or delayed response for patients not being weighed.

 o Improve patient outcomes and prevent over/under doses by standardizing the unit of measure (for example, g, kg) that is used to dose weight-based drugs and eliminating the need to convert from pounds to kilograms.

 • Implementation feasibility and other relevant implementation practices:

 o Change in the culture, attitudes and practices regarding the need to actually weigh patients and that the weight should be in metric units only.

 o Locations where a patient's weight is documented may need to be modified, including:

 ▪ Paper-based document such as policies, guidelines and protocols and orders sets.

 ▪ Computer-based documentation, including electronic health records.

 o Resources required to assess the number and types of scales within the facility.

 o Need to set current scales to measure in metric units only or purchase scales that weigh only in metric units.

 o Need to purchase metric scales for those locations that do not have scales available to accommodate various patient populations (for example, stretchers with scales, floor scales that can weigh the patient and stretcher).

 o Have charts that provide conversions from kilograms (or grams for pediatric patients) to pounds available near all scales so patients and caregivers can be told the patient's weight in pounds, if requested.

 • Cost impact to patients, payors and medical facilities:

 o Purchase of scales where needed.

 o Resources:

 ▪ Make software modifications

 ▪ Update policies and medication-related forms that include areas to document patient weights.

 ▪ Provide staff education.

 1. Importance of measuring in metric units.

 2. Updates to policies, procedures, protocols, forms and software.


1 Bailey, B. R., Gaunt, M. J., Grissinger, M. (2016), ''Update on Medication Errors Associated with Incorrect Patient Weights,'' Pennsylvania Patient Safety Advisory, 13(2), 50—57, retrieved from

2 Stucky, E. R. (2003), ''Prevention of Medication Errors in the Pediatric Inpatient Setting,'' Pediatrics, 112(2), 431—436.

3 Barrow, T., et al. (2016), ''Estimating Weight of Patients with Acute Stroke When Dosing for Thrombolysis,'' Stroke, 47(1), 228—231, retrieved from

4 Lin, B. W., et al. (2009), ''A Better Way to Estimate Adult Patients' Weights,'' The American Journal of Emergency Medicine, 27(9), 1060—1064, retrieved from

5 Herout, P. M., Erstad, B. L. (2004), ''Medication Errors Involving Continuously Infused Medications in a Surgical Intensive Care Unit,'' Critical Care Medicine, 32(2), 428—432, retrieved from

6 Fuller, B. M., et al. (2013), ''Emergency Department Vancomycin Use: Dosing Practices and Associated Outcomes,'' The Journal of Emergency Medicine, 44(5), 910—918, retrieved from

7 Michaels, A. D., et al. (2010), ''Medication Errors in Acute Cardiovascular and Stroke Patients: A Scientific Statement from the American Heart Association,'' Circulation, 121(14):1664—1682, retrieved from

8 ''Medication Errors: Significance of Accurate Patient Weights,'' Pennsylvania Patient Safety Advisory, 2009, 6(1), 10—15, retrieved from

9 Institute for Safe Medication Practices (2017), ''Targeted Medication Safety Best Practices for Hospitals,'' retrieved from

Executive Director
Patient Safety Authority

Department of Health

[Pa.B. Doc. No. 18-1430. Filed for public inspection September 7, 2018, 9:00 a.m.]

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