Ornipressin is a potent vasoconstrictor agent, and plasma volume expansion with albumin to improve effective arterial blood volume. In vitro: Ornipressin produces a profound vasoconstrictive effect by contracting smooth-muscle cells in the vascular bed, especially in capillaries, small arterioles and venules. Ornipressin is most commonly used to treat bleeding oesophageal varices.
The haemostatic effect of a high concentration of ornipressin 5 IU/10 mls lidocaine was studied in 127 patients undergoing rhinosurgery under two types of general anaesthesia. Under halothane/enflurane anaesthesia blood pressure and heart rate remained nearly constant up to 15 minutes following local injection of ornipressin into the nasal tissues. Good haemostasis was achieved in 86.5 percent of cases. Under diazepam/fentanyl anaesthesia an elevation of blood pressure was observed following infiltration of ornipressin. Thus the high concentration cannot be recommended for cases with blood pressure dyscrasias. The haemostatic effect was either good in only 60 percent of the patients.
Sigg, O., Pirsig, W., & Hirlinger, W. K. (1983). Ornipressin as vasoconstrictor in rhinosurgery. Rhinology, 21(2), 159-164.
We sought to evaluate the efficacy and side effect profile of a small dose of ornipressin, a vasopressin agonist specific for the V1 receptor, administered to reverse the hypotension associated with combined general/epidural anesthesia. A total of 60 patients undergoing intestinal surgery were studied. After the induction of anesthesia, 7-8 mL of bupivacaine 0.5% with 2 microg/kg clonidine and 0.05 microg/kg sufentanil after an infusion of 5 mL of bupivacaine 0.06% with 0.5 microg x kg(-1) x h(-1) clonidine and 0.1 microg/h of sufentanil were administered by an epidural catheter placed at T7-8 vertebral interspace. When 20% reduction of baseline arterial blood pressure developed, patients were randomly assigned to receive, in a double-blinded design, dopamine started at 2 microg x kg(-1) x min(-1), norepinephrine started at 0.04 microg x kg(-1) x min(-1), or ornipressin started at 1 IU/h. Fifteen patients presenting without hypotension were used as control subjects. Beside routine monitoring, S-T segment analysis, arterial lactacidemia, and gastric tonometry were performed. Ornipressin restored arterial blood pressure after 8 +/- 2 vs 7 +/- 3 min in the norepinephrine group and 11 +/- 3 min in the dopamine group (P < 0.05). This effect was achieved with 2 IU/h of ornipressin in most of the patients (11 of 15). Ornipressin did not induce any modification of the S-T segment; however, it significantly increased intracellular gastric PCO(2) (P < 0.05), indicating splanchnic vasoconstriction.
De Kock, M., Laterre, P. F., Andruetto, P., Vanderessen, L., Dekrom, S., Vanderick, B., & Lavand’homme, P. (2000). Ornipressin (Por 8): an efficient alternative to counteract hypotension during combined general/epidural anesthesia. Anesthesia & Analgesia, 90(6), 1301-1307.