Volume-targeted ventilation and arterial carbon dioxide in neonates

To review the arterial carbon dioxide tensions (PaCO(2)) in newborn infants ventilated using synchronized intermittent mandatory ventilation (SIMV) in volume guarantee mode (using the Dräger Babylog 8000+) with a unit policy targeting tidal volumes of approximately 4 mL/kg.

Data on ventilator settings and arterial PaCO(2) levels were collected on all arterial blood gases (ABG; n = 288) from 50 neonates (<33 weeks gestational age) ventilated using the Dräger Babylog 8000+ ventilator (Dräger Medizintechnik GmbH, Lübeck, Germany) in SIMV plus volume guarantee mode. Data were analysed for all blood gases done on the entire cohort in the first 48 h of life and a subanalysis was done on the first gas for each infant (n = 38) ventilated using volume guarantee from admission to the nursery. The number of ABG showing severe hypocapnoea (PaCO(2) < 25 mmHg) and/or severe hypercapnoea (PaCO(2) > 65 mmHg) were determined.

The mean (SD) PaCO(2) during the first 48 h was 46.6 (9.0) mmHg. The mean (SD) PaCO(2) on the first blood gas of those infants commenced on volume guarantee from admission was 45.1 (12.5) mmHg. Severe hypo- or hypercapnoea occurred in 8% of infants at the time of their first blood gas measurement, and in <4% of blood gas measurements in the first 48 h.

Infants ventilated with volume guarantee ventilation targeting approximately 4 mL/kg (range: 2.9-5.1) have acceptable PaCO(2) levels at the first blood gas measurement and during the first 48 h of life; and avoid severe hypo- or hypercapnoea over 90% of the time.