Weight-Based Estimation of Insertion Length of the Nasogastric Tube in Extremely Low Birth-Weight Infants.

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 × weight [kg] + 10 [BW < 1.0 kg]) or (3 × 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.

Application of transcutaneous carbon dioxide tension monitoring with low electrode temperatures in premature infants in the early postnatal period.

OBJECTIVE: The aim of this article is to evaluate the accuracy, precision, and safety of transcutaneous carbon dioxide tension (TcPCO2) monitoring at different electrode temperatures in preterm infants in the early postnatal period. STUDY DESIGN: A total of 26 neonates with a median birth weight of 974 g (432-1,694 g) and gestational age of 28.0 weeks (26.1-31.3 weeks) were studied in the first 5 days of life. A total of 252 simultaneous pairs (TcPCO2 and arterial carbon dioxide tension [PaCO2]) were analyzed at 38, 39, and 40°C at 26 and 27 weeks, and at 38, 39, 40, and 42°C at 28 to 31 weeks. RESULTS: The mean difference of TcPCO2 and PaCO2 (bias) increased from 3.93 mm Hg at 42°C to 5.64 mm Hg at 40°C, 6.58 mm Hg at 39°C, and 6.07 mm Hg at 38°C. Standard deviation (SD) of the bias increased from 4.17 mm Hg at 42°C to 4.76 mm Hg at 40°C, 5.29 mm Hg at 39°C, and 5.07 mm Hg at 38°C. Adverse skin lesions were not observed. CONCLUSION: TcPCO2 measurements are the most accurate and precise at an electrode temperature of 42°C. However, in premature babies, monitoring at 38, 39, and 40°C is possible provided a bias correction of 6 mm Hg and SD of 5 mm Hg are applied.

Nonlinear mixed effects model analysis of the pharmacokinetics of routinely administered bepridil in Japanese patients with arrhythmias.

This study was performed to evaluate variability in the pharmacokinetics of bepridil in 38 Japanese patients with arrhythmias, and to investigate the effects of aprindine as well as CYP2D6 and CYP3A5 polymorphisms on the oral clearance of bepridil. We determined the polymorphic alleles of CYP2D6 and CYP3A5 in each subject. The plasma concentration of bepridil at steady-state following repetitive oral administration was measured with an HPLC-based method, and the oral clearance was estimated using the nonlinear mixed effects model (NONMEM) program. Mean oral clearance was significantly greater in the patients with the CYP2D6*10 allele than in those without it. On the other hand, no significant effect of the CYP3A5 polymorphism was observed on the pharmacokinetics of bepridil. In addition, aprindine seemed to reduce the oral clearance of bepridil in the patients with the CYP2D6*10 allele.