Patient selection: from 3 days to 10.8 years of age
Parameters:
(1) crown-heel length (height) in centimeters
(2) crown-rump length in centimeters
(3) distance from suprasternal notch to the anterior superior iliac spine (SIS) in centimeters
When a tube is placed for monitoring the intraluminal esophageal pH, its position is checked by an imaging study. The 2 standard placements are:
(1) at the level of the lower esophageal sphincter (LES), which corresponds to the level of the diaphgram
(2) at a point 87% of the distance to the LES (which ensures it is not placed in the stomach), which corresponds to the level of the mid right atrium
Equations for Estimating the Distance from the Nares to the Diaphragm
distance from nares to diaphragm =
= (0.24 * (height in cm)) + 5.2
= (0.47 * (crown rump length in cm)) + 0.57
= (0.90 * (SIS in cm)) + 1.3
Equations for Estimating the Distance from the Nares to the Mid-Right Atrium (MRA)
distance from nares to mid-right atrium =
= (0.20 * (height in cm)) + 4.8
= (0.40 * (crown rump length in cm)) + 0.86
= (0.70 * (SIS in cm)) + 1.2
