Test weighing: determining precision using a ‘double-check weighing’ method

Rationale: test weighing is used extensively to assess intake in breastfed infants. Data regarding its precision however differ and are contradictory. There is discussion about the technique and scales used. Our goal is to use a double check weighing procedure on 2 different scales and determine precision in a large group of newborn infants.

Objective: to determine the precision of test weighing on 2 different scales in 2 different intake groups: feeds up to 20 cc and feeds of 20cc and more.

Study design: diagnostic accuracy study in a cohort of newborn infants.

Study population: All exclusively bottle or nasogastric fed infants in the neonatal ward are deemed eligible.

Intervention: infants are weighed twice before and twice after a feed in a standardized way by an independent investigator, unaware of the amount drunk. The weights before, as well as the weights after feeding, have to be within 5 grams. Otherwise a third weight has to be obtained. The difference between the averaged weights before and the averaged weights after feeding is taken to reflect intake in cc. The actual amount drunk will be determined by weighing the bottles before and after feeding.

Main study parameters/endpoints: precision will be calculated by determining the standard deviation of the mean of the difference between the test weighing amount and actual amount drunk.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Risks are negligible. Weighing is a routine procedure done in all neonatal wards. Weighing will be done in infants who are about to be fed, so it will not interfere with sleep or resting.

Test weighing using a double-check weighing method is precise in determining infant intake: in more than 90% of weighings test weighing will be within 5ml of the actual amount drunk

not applicable.

none