Hemodynamic effects of tracheal administration of vasopressin in dogs

Background: Intravenous administration of vasopressin during cardiopulmonar y resuscitation (CPR) has been shown to be more effective than optimal dose s of epinephrine. Earlier studies had been performed on a porcine model, bu t pigs produce lysine vasopressin hormone, while humans and dogs do not. Th is study was designed to compare the effects of tracheal vasopressin with t hose of NaCl 0.9% (placebo) on haemodynamic variables in a dog model. Metho ds: Five dogs were allocated to receive either vasopressin 1.2 U/kg or plac ebo (10 ml of NaCl 0.9%) via the tracheal route after being anesthetized an d ventilated. Haemodynamic variables were determined and arterial blood gas es were measured. Results: All animals of the vasopressin group demonstrate d a significant increase of the systolic (from 135 +/-7 to 165 +/-6 mmHg, P <0.05), diastolic (from 85<plus/minus>10 to 110 +/- 10 mmHg, P<0.05) and me an blood pressure (from 98.5<plus/minus>3 to 142.2 +/-5, P<0.05). Blood pre ssure rose rapidly and lasted for more than an hour (plateau effect). Heart rate decreased significantly following vasopressin (from 54<plus/minus>9 t o 40 +/-5 beats per min, P<0.05) but not in the placebo group. These change s were not demonstrated with placebo injection. Conclusion: Tracheal admini stration of vasopressin was followed by significantly higher diastolic, sys tolic and mean blood pressures in the vasopressin group compared with the p lacebo group. Blood gases remained unchanged in both groups. Vasopressin ad ministered via the trachea may be an acceptable alternative for vasopressor administration during CPR, when intravenous access is delayed or not avail able, however, further investigation is necessary. (C) 2001 Elsevier Scienc e Ireland Ltd. All rights reserved.