The utility of pediatric age‐based weight estimation formulas for emergency drug dose calculations in obese children

Abstract

Objectives In obese children, when drug therapy is required during emergency care, an estimation of ideal body weight is required for certain drug dose calculations. Some experts have previously speculated that age‐based weight estimation formulas could be used to predict ideal body weight. The objectives of this study were to evaluate how accurately age‐based formulas could predict ideal body weight and total body weight in obese children. Methods Three age‐based weight estimation formulas were evaluated in a secondary analysis, using a pooled sample of children from 3 academic emergency departments in South Africa. The estimates produced by the 3 formulas (and the PAWPER XL tape as a control) were compared against measured total body weight and ideal body weight. The percentages of estimates falling within 10% of the standard weight were used as the primary outcome measure (PW10). Results This study included 1026 children. For ideal body weight estimations in obese children, the old Advanced Life Support formula, the new Advanced Life Support formula, and the Best Guess formula achieved PW10s (with 95% confidence intervals [CIs]) of 29% (27.2%, 30.8%), 41.4% (38.9%, 43.9%), and 48.3% (45.3%, 51.3%), respectively. For total body weight estimations, the formulas achieved PW10s of 3.6% (3.4%, 3.8%), 5.2% (4.9%, 5.5%), and 19.0% (17.8%, 20.2%). The PAWPER XL tape achieved an accuracy of ideal body weight estimation of 100% (93.9%, 100%) and total body weight estimation of 49.7% (46.7%, 52.7%) in obese children. Conclusions The age‐based formulas were substantially less accurate at estimating total body weight and ideal body weight than existing length‐based methods such as the PAWPER XL tape, and should not be used for this purpose.

Estimating Lean Body Weight in Adults With the PAWPER XL-MAC Tape Using Actual Measured Weight as an Input Variable

“…Weight-based drug therapy in obese patients is complicated by the need to use the appropriate weight scalar for each drug administered [ 1 , 2 ]. In general, lipophilic drugs should be dosed to total body weight (TBW) and hydrophilic drugs to ideal body weight (IBW) or lean body weight (LBW) [ 3 , 4 ].…”

Human Factor Errors in the use of the PAWPER Tape Systems: An Analysis of Inter-Rater Reliability

“…However, it is important to establish the human factor errors that could potentially be associated with its use by untrained or minimally trained individuals. Since an accurate drug dose depends on an accurate estimation of weight, this is a critical consideration [18].…”