Model to estimate abdominal wall thickness in children undergoing placement or replacement of gastrostomy devices

Abdominal wall thickness (AWT) is a key measurement when placing or replacing low profile gastrostomy devices. This measurement varies, depending on nutritional status and body habitus. We developed a mathematical model to estimate AWT using a compendium of body measurements.

Ultrasonography was used to measure AWT at the initial gastrostomy site in subjects aged 22 days to 24 years old. Other body measurements (height, weight, waist circumference and distance from xiphisternum to pubis) were also obtained. Multiple linear regression was used to develop two separate models using age of 2 years to separate the groups. For analysis, AWT is log transformed.

Data from 97 subjects were used for analysis. The final model for those ≤24 months old is the following: ln(Estimated AWT) = -1.255 + 0.082*(1 if age 3-24 months, 0 if <3 months) + 0.022*(waist circumference in cm). The final model for those >24 months old is the following: ln(Estimated AWT) = -1.335 + 0.271*(1 if age >84 months, 0 if 24-84 months) + 0.082*(BMI) CONCLUSION: This model to estimate AWT is useful for determining the length of a gastrostomy device at initial placement and with subsequent changes. More data are needed to refine and further validate the model.

Level IV, study of prognostic test.