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  1. Kato, Yuta RN
  2. Hirata, Katsuya MD
  3. Oshima, Yukari RN
  4. Wada, Kazuko MD


Background: Nasogastric (NG) tubes are used in the neonatal intensive care unit (NICU) for various indications. However, evidence of the best practice for estimating the NG tube insertion length in extremely low birth-weight (ELBW) infants is limited.


Purpose: To determine a weight-based estimation formula of NG tube length in ELBW infants.


Methods: This prospective study was performed at a single-center level III neonatal intensive care unit. Low birth-weight infants admitted between May 2009 and May 2010 who required radiography for clinical reasons were included. Radiographs of participants whose current body weights (BWs) were less than 2500 g were reviewed, and the appropriate ideal insertion length of the NG tube adjusted based on radiographs and the infant's current BW was assessed. A regression model was used to determine the ideal insertion length of the NG tube with respect to the current BW.


Results: Overall, 533 radiographs (152 patients weighing 422-2486 g) were analyzed. Among the patients, 246 had BWs less than 1000 g and 287 had BWs more than 1000 g. Formulas that predicted NG tube length (centimeters) were derived as follows: (5 x weight [kg] + 10 [BW < 1.0 kg]) or (3 x weight [kg] + 12.5 [1.0 < BW <2.5 kg]).


Implications for Practice: The application of the weight-based formula for estimating the NG tube length derived from the present study together with commonly used morphological methods may improve the accuracy of the NG tube insertion procedure in ELBW infants.


Implications for Research: Further studies in other cohorts are needed.