Thalamonal, droperidol and fentanyl in induced hypovolaemic shock in the conscious dog.

Previous studies had shown that Thalamonal exerts a protective activity against hypovolaemic shock in experimental animals as well as in patients. The purpose of the present study was to make a long-term evaluation of the value of single doses of Thalamonal fentanyl and droperidol as shock-protecting agents in conscious dogs which received no replacement of blood loss. The study was conducted in 20 animals in which devices were implanted for measuring heart rate, arterial and venous blood pressure, left ventricular and left atrial blood pressure. The dogs were divided into 4 groups, receiving 20 ml of an i.v. injection containing either 0.025 mg/kg fentanyl, 0.625 mg/kg droperidol, 0.25 ml/kg Thalamonal (0.625 mg/kg droperidol + 0.0125 mg/kg fentanyl), or saline. Thalamonal allowed a 100 per cent survival of the dogs, one of the 5 animals survived in the droperidol group, whereas fentanyl and saline were completely ineffective. As a possible mechanism of action the interruption of the vicious sequence of blood loss, vasoconstriction and circulatory arrest at a peripheral and/or central level is discussed. The hypothesis of intracorporeal blood volume correction under the influence of Thalamonal as an anti-vasoconstrictor seems to be logical but needs further investigation.