How safe is intermittent positive pressure ventilation in preterm babies ventilated from delivery to newborn intensive care unit?
OBJECTIVE
To examine whether clinically determined ventilator settings will produce acceptable arterial blood gas values on arrival, in preterm infants ventilated from delivery to the newborn intensive care unit (NICU). Further, to examine the usefulness of tidal volume and minute ventilation measurements at this time.


METHODS
A prospective observational cohort study in a tertiary level 3 NICU.


METHODS
Twenty six preterm infants requiring intubation and mechanical ventilation at the point of delivery to the NICU.


METHODS
Infants who required mechanical ventilation were monitored with a blinded Ventrak 1550 dynamic lung function monitor from the point of delivery to the NICU. A Dräger Babylog 2000 transport ventilator was set up to achieve adequate chest wall movement, and FIO(2) was adjusted to achieve preductal SaO(2) of 90-98%. Dynamic lung function monitoring data were recorded and related to the arterial blood gas taken on arrival.


RESULTS
Mean gestation was 28 weeks (range 23-34) and mean birth weight was 1180 g (range 480-4200). A quarter (26% (95% confidence interval (CI) 12% to 48%)) were hypocarbic, with 20% (95% CI 7% to 39%) below 25 mm Hg, and 38% (95% CI 20% to 60%) had hyperoxia. Some (20% (95% CI 7% to 39%)) were both hypocarbic and hyperoxic. Total minute ventilation per kilogram correlated significantly with the inverse of PaCO(2) (p < 0.001).


CONCLUSIONS
Clinically determining appropriate mechanical ventilation settings from the point of delivery to the NICU is difficult, and inadvertent overventilation may be common. Severe hyperoxia can occur in spite of adjustment of the FIO(2) concentration to achieve an SaO(2) range of 90-98%. Limiting minute ventilation during resuscitation may prevent hypocarbia.
Tracy
M
M
Department of Paediatrics and Child Health Sydney University, Nepean Hospital, Sydney, NSW 2747, Australia. tracym@wahs.nsw.gov.au
Downe
L
L
Holberton
J
J
D001724:Birth Weight; D001784:Blood Gas Analysis / Q000379:methods; D002245:Carbon Dioxide / Q000032:analysis; D036861:Delivery, Obstetric; D005260:Female; D005865:Gestational Age; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000503:physiopathology / Q000628:therapy*; D007363:Intensive Care Units, Neonatal; D007385:Intermittent Positive-Pressure Ventilation / Q000009:adverse effects*; D008297:Male; D011446:Prospective Studies; D012129:Respiratory Function Tests / Q000379:methods; D012151:Resuscitation / Q000379:methods; D013990:Tidal Volume
D002245:Carbon Dioxide