Effect of sustained inflation duration; resuscitation of near-term asphyxiated lambs.
OBJECTIVE
The 2010 ILCOR neonatal resuscitation guidelines do not specify appropriate inflation times for the initial lung inflations in apnoeic newborn infants. The authors compared three ventilation strategies immediately after delivery in asphyxiated newborn lambs.


METHODS
Experimental animal study.


METHODS
Facility for animal research.


METHODS
Eighteen near-term lambs (weight 3.5-3.9 kg) delivered by caesarean section.


METHODS
Asphyxia was induced by occluding the umbilical cord and delaying ventilation onset (10-11 min) until mean carotid blood pressure (CBP) was ≤22 mm Hg. Animals were divided into three groups (n=6) and ventilation started with: (1) inflation times of 0.5 s at a ventilation rate 60/min, (2) five 3 s inflations or (3) a single 30 s inflation. Subsequent ventilation used inflations at 0.5 s at 60/min for all groups.


METHODS
Times to reach a heart rate (HR) of 120 bpm and a mean CBP of 40 mm Hg. Secondary outcome was change in lung compliance.


RESULTS
Median time to reach HR 120 bpm and mean CBP 40 mm Hg was significantly shorter in the single 30 s inflation group (8 s and 74 s) versus the 5×3 s inflation group (38 s and 466 s) and the conventional ventilation group (64 s and 264 s). Lung compliance was significantly better in the single 30 s inflation group.


CONCLUSIONS
A single sustained inflation of 30 s immediately after birth improved speed of circulatory recovery and lung compliance in near-term asphyxiated lambs. This approach for neonatal resuscitation merits further investigation.
Department of Paediatrics, University Hospital of North Norway, N-9038 Tromsø, Norway. claus.klingenberg@unn.no
Claus
C
Klingenberg
Kristina S
KS
Sobotka
Tracey
T
Ong
Beth J
BJ
Allison
Georg M
GM
Schmölzer
Timothy J M
TJ
Moss
Graeme R
GR
Polglase
Jennifer A
JA
Dawson
Peter G
PG
Davis
Stuart B
SB
Hooper
D000818:Animals; D000831:Animals, Newborn; D001237:Asphyxia / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D007327:Insufflation / Q000379:methods*; D008168:Lung / Q000503:physiopathology*; D012151:Resuscitation / Q000379:methods*; D034561:Sheep, Domestic