Incidence of hypo- and hyper-capnia in a cross-sectional European cohort of ventilated newborn infants.

OBJECTIVE: To determine the incidence of hypo- and hyper-capnia in a European
cohort of ventilated newborn infants. DESIGN AND SETTING: Two-point
cross-sectional prospective study in 173 European neonatal intensive care units.
PATIENTS AND METHODS: Patient characteristics, ventilator settings and
measurements, and blood gas analyses were collected for endotracheally ventilated
newborn infants on two separate dates. RESULTS: A total of 1569 blood gas
analyses were performed in 508 included patients with a mean+/-SD Pco2 of 48+/-12
mm Hg or 6.4+/-1.6 kPa (range 17-104 mm Hg or 2.3-13.9 kPa). Hypocapnia (Pco2<30
mm Hg or 4 kPa) and hypercapnia (Pco2>52 mm Hg or 7 kPa) was present in,
respectively, 69 (4%) and 492 (31%) of the blood gases. Hypocapnia was most
common in the first 3 days of life (7.3%) and hypercapnia after the first week of
life (42.6%). Pco2 was significantly higher in preterm infants (49 mm Hg or 6.5
kPa) than term infants (43 mm Hg or 5.7 kPa) and significantly lower during
pressure-limited ventilation (47 mm Hg or 6.3+/-1.6 kPa) compared with
volume-targeted ventilation (51 mm Hg or 6.8+/-1.7 kPa) and high-frequency
ventilation (50 mm Hg or 6.7+/-1.7 kPa). CONCLUSIONS: This study shows that
hypocapnia is a relatively uncommon finding during neonatal ventilation. The
higher incidence of hypercapnia may suggest that permissive hypercapnia has found
its way into daily clinical practice.