Predicting Dexamethasone-Associated Extubation Success in Preterm Infants

Dexamethasone improves respiratory status in some preterm infants with lung disease. Dexamethasone increases heart rate (HR) variability, which decreases the heart rate characteristics index (HRCi), a sepsis risk score that reflects inflammation. Respiratory improvement can be measured by the ability to wean support, quantified by a respiratory severity score (RSS). We hypothesized that HRCi and RSS early in dexamethasone treatment are associated with respiratory improvement marked by successful extubation.

We retrospectively reviewed neonatal intensive care unit (NICU) patients born at < 32 weeks gestational age (GA) admitted from 2012 to 2022 who received > 3 days of dexamethasone for lung disease while on mechanical ventilation. Daily mean FiO₂, HRCi, and RSS (mean airway pressure × FiO₂) were calculated for the dexamethasone start day and 2 days before and after. Successful extubation was defined as occurring during the dexamethasone course without reintubation within 7 days. We compared variables between infants with and without successful extubation.

A total of 65 infants (mean GA: 25 ± 1 weeks) were included. HRCi, FiO₂, and RSS significantly decreased by day 3 of dexamethasone. Successful extubation (n = 38) was associated with higher postmenstrual age (PMA), lower FiO₂ and RSS, and being on conventional rather than high-frequency ventilation (all p < 0.05). Multivariable analysis found that RSS and PMA, but not HRCi, predicted successful extubation.

Dexamethasone treatment decreased the HRCi, but this was not associated with extubation success. Higher PMA and lower respiratory support were associated with successful extubation during dexamethasone treatment.

· Fifty-eight percent of preterm infants were successfully extubated during dexamethasone treatment.. · Higher PMA and lower RSS were associated with extubation success.. · HRCs improved with dexamethasone but did not predict extubation success..