Hemodynamic effects of acute hypoxia and minute amounts of endotoxin in awake swine.

Hemodynamic measurements and arterial blood gases were determined from awake swine (n = 8) during acute hypoxia (12% O2, balance N2 for 5 minutes) and following injection of Escherichia coli endotoxin (4 microgram/kg of body weight) into the pulmonary artery. Comparison of baseline data with these treatments indicated: (1) swine exhibited a marked pulmonary pressor response to acute hypoxia (deltaBPpul = 9 to 12 mm of Hg): (2) injection of minute amounts of endotoxin led to a marked increase of pulmonary arterial blood pressure 10 to 20 minutes following the injection (deltaBPpul = 15 mm of Hg); and (3) the pulmonary pressor response to a 2nd exposure of acute hypoxia was unaffected by the intervening endotoxin injection.