Using Point-of-Care Ultrasound to Assess Gastrostomy Balloon Placement

Fluoroscopy is the gold standard for evaluation of gastrostomy tube (GT) placement, though it is costly and resource-intensive. Point-of-care ultrasound (POCUS) has potential as a low-risk alternative to confirm GT placement.

To determine the diagnostic accuracy of POCUS for identification of correct gastrostomy balloon placement as compared to fluoroscopy.

This was a prospective convenience sample of children presenting to interventional radiology for routine GT or gastrojejunal (GJ) tube exchange. Prior to exchange, POCUS operators scanned and interpreted ultrasound images for GT placement, followed by fluoroscopy. A blinded radiologist interpreted fluoroscopic studies. Diagnostic test characteristics, concordance with 95% confidence intervals, and interrater agreement (Cohen's Kappa) between POCUS and fluoroscopy were calculated.

Four (3%) of 118 evaluated GT balloons were displaced. Compared to fluoroscopy, novice POCUS assessment of GT/GJ balloon placement had a sensitivity of 87% (79%-92%), specificity of 25% (1%-81%), PPV of 97% (92%-99%), NPV of 6% (1%-30%), proportion agreement of 85%, (77%-91%) kappa 0.04. Expert POCUS interpretation exhibited sensitivity of 91% (84%, 96%), proportion agreement of 89% (82%-94%), kappa 0.09. pH testing had the highest sensitivity of 93% (85%, 97%), proportion of agreement 92% (84%-97%) and kappa 0.19.

POCUS demonstrated a high sensitivity and concordance for GT/GJ balloon placement, with low interrater agreement with fluoroscopy. POCUS may not add additional clinical benefit in routine evaluation of GTs over current standards of care. However, POCUS may serve as a useful screening test in settings where fluoroscopy is unavailable or pH is unobtainable.