Sequential changes of hemodynamics and blood gases in newborn piglets with developing pneumothorax.
BACKGROUND
Little information is available regarding the temporal changes in hemodynamics and blood gases during the development of a moderate pneumothorax in a neonate. In this study, we aim to investigate the temporal changes of hemodynamics and arterial blood gases in a neonatal swine model of unilateral pneumothorax.


METHODS
Prospective observational controlled animal research.


METHODS
Experimental pneumothorax (n = 9) was created by intermittent progressive introduction of 10 ml/kg of room-air every 5 min to a total 40 ml/kg, via a 20G Insyte(R) angiocatheter placed in the fourth intercostal space in line with the right frontal limb. Changes in heart rate, mean arterial pressure, central venous pressure (CVP), common carotid arterial flow (CCAF) and arterial blood gases were measured and compared with the normoxic baseline and a control group (n = 7) (ANOVA).


RESULTS
As the pneumothorax developed, SaO2 and PaO2 deteriorated after injecting 20 ml/kg of room-air (P < 0.001 vs. baseline and control), whereas the pH and PaCO(2) remained unchanged. CVP increased after injecting 30 ml/kg of room-air (P < 0.001), with no significant changes in heart rate and mean arterial pressure. Meanwhile, CCAF increased and carotid oxygen delivery declined after 30 ml/kg (P < 0.05).


CONCLUSIONS
Deterioration in oxygenation was noted early in the development of pneumothorax in newborn piglets followed by metabolic acidosis. CVP progressively increased despite the lack of significant changes in systemic hemodynamics when moderate pneumothorax developed. Although CCAF increased during a moderate pneumothorax, carotid oxygen delivery decreased.
Liu
Jiangqin
J
Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
Joynt
Chloe
C
Tymafichuk
Corinne
C
Cheung
Po-Yin
PY
D000818:Animals; D000831:Animals, Newborn; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D006439:Hemodynamics; D011030:Pneumothorax / Q000097:blood* / Q000503:physiopathology*; D012720:Severity of Illness Index; D013552:Swine