Comparison of the depressive effects of four anesthetic regimens on ventilatory and cardiovascular variables in the guinea pig.

BACKGROUND AND PURPOSE: Guinea pigs are one of the most difficult rodents to anesthetize safely, and as a consequence, there is a paucity of reports regarding the effects of anesthesia on their cardiorespiratory variables. We used long-term indwelling cannulas for studying the guinea pig in the conscious state, and subsequently investigated the effects of four types of injectable anesthetic regimens on cardiorespiratory variables. METHODS: Using barometric plethysmography (conscious: long-term cannulated, n = 11; no cannulation, n = 28) or trachea-out plethysmography (anesthetized: n = 7 for each of the four groups), we recorded ventilatory, cardiovascular, metabolic, and arterial gas variables during air breathing and in response to 10 min of hypoxia (8% O2) and 10 min of hypercapnia (8% CO2). The four anesthetic regimens tested were: Saffan (infused at 9.75 mg/kg of body weight/h, i.v.); ketamine/xylazine (14.6/3.7 mg/kg/h, i.v.); pentobarbitone (8.3 mg/kg/h, i.v.) plus Innovar Vet (0.15 mg/kg every 1 to 1.5 h, s.c.); or pentobarbitone alone (22 mg/kg/h, i.v.). RESULTS: The least depressive anesthetic with regard to ventilation (VE) was ketamine/xylazine. Air breathing was depressed by only 17% (cf approx 50 to 60% for all other regimes), and the VE responses to hypoxia and hypercapnia were attenuated the least. All anesthetics equally depressed mean arterial blood pressure (from 70 mmHg to 56 mmHg) and ketamine/xylazine was the only anesthetic to reduce heart rate (from 260 beats/min to 198 beats/min). CONCLUSION: Although all anesthetics induce cardiorespiratory depression to some extent, the use of ketamine/ xylazine is recommended for future use in respiratory studies of the guinea pig where anesthesia cannot be avoided.

Complications of saffan anaesthesia in cats.

Complications associated with Saffan anaesthesia were recorded following 100 administrations of the anaesthetic to cats. Hyperaemia or oedema of the pinnae or forepaws was recorded in 69 per cent of administrations. Other common complications included coughing and partial laryngean spasm at intubation, cyanosis, postoperative vomiting and opisthotonus. Suggestions are made for minimising the incidence of such complications.

Clinical study of althesin and hypnomidate.

A simple clinical and a more elaborate instrumental study are presented on the cardio-circulatory action of Althesine and Etomidate (Hypnomidate) compared to thiopental (Pentothal). Statistically is Althesin not significantly worse than thiopental but significantly worse than Hypnomidate. Hypnomidate is less aggressive than thiopental although non significantly. Succinylcholine (1 mg/kg) aggravates the heart depressant actions of the tested drugs, while the intubation of the trachea produces sometimes a serious pressor response which can not be always blocked by prior administration of a low dose (0.1 mg i.v.) Fentanyl.

[Epidemiologic characteristics of 21 peranesthetic anaphylactoid accidents observed in a population of 12,855 surgically treated patients]. / Caractéristiques épidémiologiques de 21 accidents anaphylactoïdes peranesthésiques observés dans une population de 12 855 sujets opérés.

A study of anaphylactoid reactions (AR) observed between September 1982 and September 1983 was carried out in the surgical departments of a French regional hospital. The patients who had presented clinical symptoms suggesting an AR (bronchospasm, collapse, tachycardia, with or without skin rash) during a general anaesthesia were included in this study. A precise history of previous anaesthesias and allergy was taken; allergological testing was carried out six to eight weeks after the AR. It included intradermal skin tests (ST) and a human basophil degranulation test (HBDT) with the suspected drugs. Out of 12,855 patients operated on under general anaesthesia in the hospital, 21 AR were seen during the year under study, in 18 women and 3 men, of median age 27 years (extreme values: 11 and 62). The median number of previous anaesthesias was 2 (extreme values: 0--in 4 cases- and 22). Cardiocirculatory abnormalities were the most frequent clinical symptoms of the AR: they consisted of decreased arterial pressure in 13 cases, with 8 cases of vascular collapse. Respiratory symptoms were less frequent but severe bronchospasm was observed in 5 cases. Skin rashes were seen simultaneously in 13 out of the 21 observations. A history of allergy was found in 11 patients. Total IgE serum concentration averaged 134 kU X 1(-1) (extreme values: 32-378). Results of histamine-sensitivity skin tests were not significantly different from those observed in a control group. Calcemia and magnesemia were in the normal range. One to four drugs were tested in each patient: 41 tests combining ST and HBDT were carried out.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaphylactic and anaphylactoid reactions to intravenous anesthetic agents.

A brief review of anaphylactic and anaphylactoid reactions to some i.v. anaesthetic agents is presented. Etiology, mechanisms, preventive aspects and treatment are discussed.

[Blood histamine level and anaphylactic reaction under alphadione]. / Histaminémie et réactions anaphylactoïdes sous alfadione.

Histamine release is generally thought to play a major role in anaesthetic-induced anaphylactoid reactions. In 12 patients who were developing such a reaction at the start of a slow rate intra-venous infusion of alphadione, serum histamine was measured using the enzyme-isotopic assay from a blood sample drawn within the first 5 minutes following the onset of clinical signs. Histaminemia above normal value was noted in 3 patients only without clear clinical correlation. These results would suggest that histamine release is unlikely to be principally involved in this kind of adverse reaction.