I read with interest the recent article by Benson et al. on diphenhydramine dose-response.Citation1 I would like to applaud the authors for their novel approach in studying diphenhydramine overdoses reported to poison centers. Their methodology allowed for better confirmation of ingestion and estimation of amount taken than previous works. I was also encouraged to see that their findings were consistent with the current AAPCC guidelines for hospital referral relating to diphenhydramine.
However, I noticed a limitation of their data that was not addressed in the paper. My concern arises from the patient weight used to calculate individual doses. There does not appear to be any confirmation of weights based on the methods section. It is a common practice at many emergency departments to estimate patients' weight if they are unconscious or display altered mental status. Several studies have demonstrated that health care professionals are poor estimators of body weight. Estimation within 10% of actual body weight is typically achieved by only about half of the medical professionals and can lead to clinically significant dose variation.Citation2–6Underestimation of weight appears to be the most frequent type of error in adults and children by health professionals. Such variation could lead to overestimating the threshold for toxicity.
Again, I would like to applaud the authors for their novel method of estimating the amount of drug taken and encourage them to find a similarly clever method for improving the estimate of weight in poison center data.
Greene Shepherd
University of Georgia,
College of Pharmacy,
Augusta, GA,
USA
References
- Benson BE, Farooqi MF, Klein-Schwartz W, Litovitz T, Webb AN, Borys DJ, et al. Diphenhydramine dose-response: a novel approach to determine triage thresholds. Clin Toxicol 2010; 48:820–831.
- Breuer L, Nowe T, Huttner HB, Blinzler C, Kollmar R, Schellinger PD, et al. Weight approximation in stroke before thrombolysis: the waist-study: a prospective observational “dose-finding” study. Stroke 2010; 41:2867–2871.
- Hall WL, Larkin GL, Trujillo MJ, Hinds JL, Delaney KA. Errors in weight estimation in the emergency department: comparing performance by providers and patients. J Emerg Med 2004; 27:219–224.
- Corbo J, Canter M, Grinberg D, Bijur P. Who should be estimating a patient's weight in the emergency department? Acad Emerg Med 2005; 12:262–266.
- .Partridge RL, Abramo TJ, Haggarty KA, Hearn R, Sutton KL, An AQ, Givens TG. Analysis of parental and nurse weight estimates of children in the pediatric emergency department. Pediatr Emerg Care 2009; 25:816–818.
- Harris M, Patterson J, Morse J. Doctors, nurses, and parents are equally poor at estimating pediatric weights. Pediatr Emerg Care 1999; 15:17–18.