Determining Esophageal Length from Crown‐Rump Length

Abstract

SummarySince esophageal length varies linearly with height, intraluminal pH monitoring can be performed at a position within the esophagus that is determined by an equation. Alternatively, pH probes can be positioned under fluoroscopic guidance, though no radiographic landmarks indicate the position that is 87% of esophageal length (where the monitoring is usually accomplished). Our aims were to determine whether a relationship might exist between crown‐rump length and esophageal length, for use in patients in whom height is difficult or inappropriate to measure, and to determine whether the mid‐right atrium can be used as a radiographic landmark in fluoroscopic pH probe placement. Height, crown‐rump length, and distance from the suprasternal notch to the left anterior superior iliac spine were measured in 65 consecutive children undergoing 24‐h pH monitoring. As the pH probe was inserted under fluoroscopy, distances from the nose to diaphragm and mid‐right atrium were determined. Equations were derived by simple linear regression to describe the relationships between each of the body measurements and esophageal length. There is excellent correlation between crown‐rump length and the distances from the nose to diaphragm and to mid‐right atrium. The mid‐right atrium corresponds to 87% of the nose to diaphragm distance in many patients.