Affiliations: Monash Newborn, Monash Medical Centre, Clayton, VIC,
Australia | Radiology, Monash Medical Centre, Clayton, VIC,
Australia | Monash Institute of Health Services Research, Monash
Medical Centre, VIC, Australia
Abstract: Background: Presence of a hemodynamically significant ductus
arteriosus is common in preterm infants and left atria enlargement is used as a
surrogate marker. Cardiothoracic ratio may not be a reliable indicator of left
atria enlargement given its posterior location. Aims: To assess the ability of angle of naso-gastric tube
deviation to discriminate between babies with and without a hemodynamically
significant ductus arteriosus. Methodology and data analysis: Retrospective chart review and
radiographic measurements of frontal chest radiographs for babies with
hemodynamically significant ductus arteriosus that was proven by
echocardiography (ECHO) (Group I) compared with individually matched babies
with no hemodynamically significant ductus arteriosus matching on corrected
gestation age. Unrotated frontal chest radiographs done within 72 hours of echo
and gestational age matched frontal chest radiographs for Control (Group II)
were assessed for measurements of angle of naso-gastric tube deviation and
carinal angle by digital imaging technique. Results: A total of 32 babies were enrolled in each group.
Mean naso-gastric tube angle was significantly greater in babies from group I,
with average difference 4.5° (95% CI 3° to 6°.
Angle greater than 9° increased the odds of being a Group I baby (Odds
ratio 25.9, 95% CI 3.4–198). Conclusions: Measurement of naso-gastric tube angle deviation
may be helpful in babies with hemodynamically significant ductus arteriosus and
left heart volume overload.