Comparing Heel Stick Glucoses in Neonates

Newborn babies can develop low blood sugar (glucose) which can lead to brain injury and poor developmental outcomes. Therefore, it is important to accurately measure the blood glucose in babies. One way to measure the blood glucose is to test blood from the baby's heel with a bedside device called a point of care glucometer. This method is very common and easy; however, multiple factors can lead to an inaccurate reading. A false low reading may require additional blood testing and admission to the NICU. A false high reading could result in the medical provider missing the diagnosis of low blood glucose. Our team wants to know if there is a difference between blood glucose measurements taken from warmed and un-warmed heels of infants. Blood flow farther away from the heart, such as in the feet and heels, may be less than the rest of the body, and might move more slowly. This could cause the glucose level to be lower in the feet and heels. Therefore, sampling blood from an un-warmed heel may result in a falsely low glucose reading. There is some research that suggests warming the heel increases blood flow to the area; however, only one study that we know of has evaluated differences in blood glucose readings from warmed and un-warmed heels. They found significantly higher blood glucose readings from warmed heels compared to un-warmed heels in 57 babies. However, these babies were part of a larger study comparing different diets on blood glucose levels, and the heels were warmed using warm water which is no longer a current practice. The goal of this study is to compare the capillary blood glucose levels from warmed and un-warmed heels in about 100 infants who are breast and/or formula fed using the current practice of warming heels with gel heat packs. The null hypothesis is that there will be no difference between capillary blood glucose levels sampled from an infants warmed and un-warmed heel. The alternative hypothesis is that capillary blood glucose levels sampled from warmed heels will be higher than those samples from un-warmed heels.