HOW GOOD ARE DOCTORS AT ESTIMATING CHILDRENS WEIGHT

Objective-(1) To see whether children are weighed before drugs are pre scribed in an accident and emergency (A&E) department; (2) to assess h ow safe it is for doctors to guess children's weight if they prescribe ''by eye''. Methods-An audit of 100 sets of notes was performed to se e if children were weighed a before drugs were prescribed. A&E senior house officers were asked to estimate the weight of 75 children aged 1 2 years and under. Results-Children were weighed before prescribing in only two out of 100 cases. The mean difference between the actual and estimated weights was -0.21 (not significantly different from zero; P = 0.40); 95% of the estimates were within two standard deviations of the mean difference. The percentage difference between the actual and estimated weight varied between overestimates of 300% and underestimat es of nearly 100%. Conclusions-The average guess of doctors as a group was approximately correct. However, there was a wide range of estimat es for individuals. If the child's weight is guessed, the doctor could risk under- or overprescribing analgesia, sedation, or intravenous fl uids. Given the wide range of estimates, actual weights are required f or accurate prescribing. Prescribing on an age basis may be acceptable for drugs such as paracetamol or amoxycillin, but it is imperative to prescribe on a mg/kg basis for opiates, sedatives, and intravenous fl uids because of the large variation in weight that can occur for a sin gle age.