Best Practice #3 FAQ

Best Practice #3:
a) Weigh each patient as soon as possible on admission and during each appropriate1 outpatient or emergency department encounter. Avoid the use of a stated, estimated, or historical weight.
b) Measure and document patient weights in metric units only.

1 Appropriate encounters include all encounters where the patient is being seen by a licensed independent practitioner, excluding life-threatening situations where the delay involved in weighing the patient could lead to serious harm (e.g., major trauma). It is specifically meant to exclude laboratory and other services where medications are not prescribed or administered.

1. Question: Our hospital system is looking at scales and hoping to make changes to weigh patients in kilograms only. However, a question has arisen about self-reported weights; patients will know how much they weigh in pounds, not kilograms. If a field for pounds is locked out in the system, and kilograms is the only choice, the value in pounds may accidently be entered in the kilograms field, leading to possible overdose of medications. Of course, we will strive to minimize self-reported weights, but if a bed scale does not work, and the patient can’t be moved, we may rely on a self-reported weight until the patient can be moved. Besides staff awareness and education, does ISMP have any other recommendations? 

Answer: As part of this Best Practice, we recommend that staff always obtain the actual patient’s weight using scales that measure in the metric system. Numerous errors have been reported to ISMP caused by inaccurate self-reported weights, historical weights in the record, and estimated weights. In rare circumstances that a measured weight cannot be obtained, determine the best approach to obtaining the most accurate weight possible until the patient can be weighed (e.g., moved to bed with a working bed scale). If the interim weight is in non-metric units, staff will need to convert it to metric units prior to entry into the system. In these cases, pound to kilogram conversion charts at scales will help. We realize this won’t prevent all incorrect entries, especially if the conversion chart isn’t readily available or used. However, we believe there will be fewer errors if all patients are weighed on scales that weigh in metric units only. Also, hospital staff need to be engaged in finding ways to overcome barriers that may occur, such as broken bed scales, patients that shouldn’t be moved, and other issues that may arise.

The goal is to ensure that actual patient weights, not stated or estimated weights, are used, and that all patients are weighed in metric units when they enter a healthcare environment. Having scales that measure only in the metric scale is a key factor in achieving success.
Rev. 3/26/2014

2. Question: Our computer system allows entry of a patient’s weight in either pounds or kilograms, but the final weight is displayed in kilograms. Is this acceptable?

Answer: ISMP continues to receive reports of medication errors that occurred because the patient’s weight had been entered into the wrong field in the information system (e.g., pounds entered into the kilogram field, and vice versa). Subsequently, the wrong dose was calculated, ordered, dispensed, and administered. ISMP believes it is crucial to measure and document weights using only metric units (g or kg).
Rev. 3/26/2014

3. Question: What do you do when patients (especially heart failure patients or parents of newborns) want to know their weight in pounds?

Answer: Conversion charts should be available for nurses and other healthcare personnel to use when discussing measured weights with the patient and family. Having patients ask for their weight in pounds should not be a barrier to collecting or documenting the information in the metric units.
Rev. 3/26/2014