Prospective volumetric analysis of gallbladders in critically ill newborns: the impact of nutrition.

Background: Neonatal reference values of gallbladder size have been assessed in healthy newborns with enteral feeding regimen. Their applicability to critically ill patients under total parenteral nutrition (TPN) remains to be questioned.

Objective: Our aim was to evaluate the impact of short-term TPN versus enteral nutrition (EN), gender and birth weight on neonatal gallbladder volume.

Method: A prospective pilot study was initiated with a single sonographic investigator blinded towards feeding regimen. In total, 61 neonates (33 males, 28 females) were consecutively enrolled on the intensive care unit; 31 newborns were examined both under TPN and bolus EN (breast milk/formula). Patients with malformations of the biliary tract were excluded. Prior to ultrasound examinations, a minimum fasting period of 2 h was maintained. Sonographic measurements of gallbladder length, depth and width were performed to calculate gallbladder volume using the ellipsoid formula.

Results: Neonatal gallbladder volume differed significantly between TPN and EN (p < 0.001). Using TPN, range of gallbladder length, width and volume exceeded reference values. Birth weight was weakly correlated with gallbladder volume (correlation index 0.3776, p = 0.01). We found no gender-related differences.

Conclusions: Neonatal gallbladder volume under TPN was significantly larger compared to EN. Using TPN, gallbladder dimensions exceeded reference values without causing clinical complications. The benign course of gallbladder enlargement required no specific medication or surgical treatment.