Haemodynamic, diuretic and hormonal responses to prostaglandin E1 infusion in halothane anaesthetized dogs: comparison among epidural lidocaine, epidural fentanyl and epidural saline.

Deliberate hypotension decreases blood loss and transfusion but it may be accompanied by adverse effects due either to the hypotensive agents themselves or to haemodynamic alterations. Prostaglandin E1 (PGE1) has the advantage of a diuretic effect coupled with systemic hypotension. To elucidate the mechanisms by which PGE1 induces diuresis we compared the haemodynamic, diuretic and hormonal responses to PGE1 infusion simultaneously with epidural lidocaine (EP-L n = 7), epidural fentanyl (EP-F n = 8) or epidural saline (CONT n = 7) in halothane anaesthetized mongrel dogs. All groups developed a decrease in mean arterial pressure during PGE1 infusion (from 105 +/- 24 to 77 +/- 18 mmHg in EP-L; 106 +/- 19 to 79 +/- 13 mmHg in the EP-F; and 129 +/- 14 to 106 +/- 18 mmHg in the CONT groups (mean +/- SD)) (P < 0.05). In the EP-F and CONT groups urinary output increased during PGE1 infusion (from 4.31 +/- 1.89 to 6.15 +/- 2.03 ml.min-1 and 2.71 +/- 1.23 to 4.48 +/- 1.66 ml.min-1 (P < 0.05), respectively) and was accompanied by increases in renal blood flow (from 87.0 +/- 40.7 to 111.0 +/- 42.8 ml.min-1 and from 121.6 +/- 46.6 to 158.4 +/- 64.9 ml.min-1 (P < 0.05), respectively) and in fractional excretion of sodium (FENa) (from 4.78 +/- 3.88 to 7.63 +/- 5.20% in CONT group).(ABSTRACT TRUNCATED AT 250 WORDS)