How Much Does a Minimum Weight Requirement at Discharge Delay Discharge from the NICU?

Background: Our policy requires a minimum weight (wt) of 1800 grams (g) for discharge regardless of corrected gestational age. However, current AAP and Canadian guidelines recommend discharge at “physiologic maturity” (PM), regardless of wt.

Methods: We performed a retrospective chart review to 1) test the hypothesis that a clinically relevant number of hospital days ( ≥ 20days annually) could be saved if discharge occurred at PM even if < 1800g; and 2) to determine whether the difference in PM (“virtual discharge”) and actual discharge was greater in small for gestational age (SGA) infants. We studied infants with birthweight of 1300g-1800g to target those we thought would be most likely to be affected by this minimum wt policy. Sample size calculation indicated 8 babies needed to not miss a difference of 20d of hospitalization comparing virtual discharge at PM and actual discharge. Pm was defined as: 1) maintaining temperature in an open crib of ≥36.3°C for at least 48h; 2) oral feed volume of ≥120 ml/kg/day; 3) gaining wt for 2d consecutively with no enteric tube; 4) no apneas/bradycardias for 5d; 5) no desaturations for 1d. Infants with major congenital malformation/other problems that would affect discharge were excluded. Not normally distributed continuous variables were analyzed by Wilcoxon rank sum test, and chi-square or Fisher exact test used for categorical variables.

Results: There were 143 infants with birthweight of 1300g-1800g discharged in 2019. Fourteen were excluded (missing information (4), congenital anomalies (10)). Thirty-six of the remaining 129 were SGA. There was a significant difference between the day of age at discharge and when the infant reached PM of 0.55 days per infant (P-value 0.0333) resulting in 71 total hospital days for the cohort. For SGA babies, this difference was 1.47 days, while it was 0.19 days in the non-SGA babies (P–value 0.0243). For 19 infants who reached PM <1800g, there was an average of 2.63 days difference between PM and actual discharge (P-value 0.0006), contributing 50 of the 71 hospital days potentially saved; 63% of these 19 infants were SGA.

Conclusion: There is a ~0.55 day difference between age at discharge and age at PM. If these infants were discharged when they reached PM, 71 hospital days per year could have been saved. With a one day hospital room charge of $7850, ~$557,350 can be saved with discharge at PM. The minimum weight policy could have contributed to 50/71 (65%) of these hospital days. Our study did not examine if other reasons (e.g. transportation issues) would have precluded discharge at PM. If a QI project were undertaken, the SGA population would be an ideal target.