Table 3.

Pooled study results

Outcome	Gastric feedings Median (IQR)	Transpyloric feedings Median (IQR)	IRR for transpyloric feedings (95% CI)a
Intermittent hypoxemic events (no. per day)	3 (1-11)	7.5 (1-23.5)	1.8 (1.3, 2.5)
Prolonged hypoxemic events (no. per day)	0 (0-1)	0 (0-2.5)	1.9 (1.1, 3.2)
			Mean change with transpyloric feedings (95% CI)b
Proportion of time with SpO2 ≤ 80% per day (%)	0.4 (0.07-1.8)	0.8 (0.1-2.3)	1.6 (1.1, 2.5)
Mean time-weighted daily FiO2 (%)	29.2 (23.7-34.5)	29.0 (24.0-35.9)	1.0 (1.0, 1.0)

^aMixed effects negative binomial regression models were used to assess the relationship between the feeding route and rates of intermittent and prolonged hypoxemic events. IRR values indicate the average relative increase in the daily number of intermittent or prolonged hypoxemic events with transpyloric compared to gastric feedings.

^bThe daily proportion of time spent hypoxemic and the mean daily time-weighted FiO2 were log transformed and assessed using mixed effects linear regression models. Values shown for these outcomes are back-transformed (exponentiated) model parameter estimates. They indicate the average relative increase (for values >1) in the proportion of time in hypoxemia per day and the time-weighted daily FiO₂ exposure during transpyloric compared to gastric feedings.

A random effect from each individual patient and an unstructured covariance matrix with robust variance estimates were used in all models. A dichotomous variable distinguishing the first and second treatment blocks was included in the models to account for temporal variation in disease severity over time. Use of these model parameters account for the differences in the ratios of the median values for the study outcomes and the estimates of treatment effects shown in the table.

Abbreviations: CI, confidence interval; FiO₂, fraction of inspired oxygen; IQR, interquartile range; IRR, incidence rate ratio; SpO₂ peripheral capillary oxygen saturation level