Blood gas and acid--base status in spontaneously delivered, term-induced and induced premature foals

Six spontaneously delivered foals, 8 Thoroughbred foals induced at term with fluprostenol and 17 Pony foals induced prematurely with fluprostenol and oxytocin at a gestational age of 270 to 330 days were studied to determine PO2, PCO2, pH, base excess and HCO3 values in arterial blood between birth and 7 days of age. The Pony foals were subdivided into those that survived greater than 24 h (N = 9) and less than 9 h (N = 8). Blood gas and acid base values in the term-induced foals were similar to those in spontaneously delivered foals. The induced premature foals surviving greater than 24 h had significantly lower PaO2 values at 15 min, 30 min and 1 h after birth than did the term-induced foals. There were no significant differences in PaCO2 or pHa values between these groups at any measurement time. However, the premature foals had significantly lower base excess values than did the term-induced foals at birth and 30 min after birth. The induced premature foals surviving less than 9 h had significantly lower PaO2 values than did the term-induced foals at all measurement times. At the 1.5-4 h measurement, the foals surviving less than 9 h had PaO2 values significantly lower than those of the foals surviving greater than 24 h. The PaCO2 values were significantly higher and the pHa values significantly lower in the foals surviving less than 9 h than in either of the other 2 groups.