Pulmonary microembolization in experimental aortic surgery

The influence of prostaglandin E1 on systemic and pulmonary haemodynamics after aortic surgery

The influence of a peroperative prostaglandin E1 (PGE1) infusion on systemic and pulmonary haemodynamics in a porcine model of aortic surgery was studied. Twenty-four pigs were randomised to PGE1 (100 ng/kg/min) or 0.9% Saline as placebo. Haemaccel was then infused to maintain a central venous pressure (CVP) of greater than 4 less than 6 mmHg and pulmonary artery wedge pressure (PAWP) of greater than 3 less than 5 mmHg. Standardised aortic surgery consisted of midline laparotomy, small bowel exteriorisation, 1.5 h aortic clamping and 1 h shock before resuscitation. Serial measurements of blood pressure (BP), cardiac output (CO), pulmonary vascular resistance (PVR), pulmonary shunt (A-V shunt), and arterial PO2 (PaO2) were recorded during and three days after surgery. Volume loading with Haemaccel prevented a significant fall in initial BP on PGE1 at 95.1 +/- 48 mmHg compared to 102 +/- 4.9 mmHg in control animals with similar CO in the two groups. Following release of the aortic clamp all animals became profoundly hypotensive with BP falling to 74.6 +/- 3.0 and 68.7 +/- 3.2 mmHg for PGE1 and placebo respectively, but CO was protected in those animals receiving PGE1 at 1.92 +/- 0.04 compared to 1.67 +/- 0.1 L/min/m2 on placebo and remained significantly higher following resuscitation and three days later (P less than 0.05). PGE1 also reduced the marked rise in pulmonary vascular resistance to 922 +/- 84 dynes-s/cm5/m2 during shock in control animals to only 555 +/- 30 (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)