The formula for orogastric tube insertion length in preterm infants based on growth indicators and gestational age / 中国新生儿科杂志

ABSTRACT

Objective:To develop a formula for estimating the insertion length of orogastric (OG) tube for preterm infants based on growth indicators and gestational age (GA).Methods:From January 2020 to December 2021, preterm infants admitted to the neonatal intensive care unit of our hospital were retrospectively reviewed. OG tubes were inserted within 24 h of admission and the lengths of OG tubes were adjusted according to chest and abdominal X-ray results. The formula for OG tube placement was developed using stepwise regression analysis method with GA, body weight (BW) and body length (BL) as the independent variables and the corrected length of OG tube as the dependent variable. The weight-based formula developed by Freeman et al. were compared.Results:A total of 180 preterm infants were included, with 90 cases GA<32 weeks, 84 cases GA 32~35 weeks and 6 cases GA 36 weeks. No significant differences ( P>0.05) existed in the incidences of misplacement of OG tube and the specific types of misplacement among GA groups. For infants with GA≤35 weeks, the insertion length of OG tube was positively correlated with BW and BL and for preterm infants with GA 36 weeks, the insertion length of OG tube was positively correlated with BW only. Stepwise regression analysis showed the formula as OG tube length (cm)=11.8+2.1×BW (kg) or OG tube length (cm)=9.5+1.6×BW (kg)+0.091×GA (week). Comparing with the formula developed by Freeman et al., the differences of OG tube length estimated using our formula were more prominent as BW increased. Conclusions:The length of OG tube is positively correlated with BW and GA with BW shows more influence.