Effects Of Induction Agents Research Articles

Effect of induction agent on vasopressor and steroid use, and outcome in patients with septic shock

IntroductionIn seriously ill patients, etomidate gives cardiovascular stability at induction of anaesthesia, but there is concern over possible adrenal suppression. Etomidate could reduce steroid synthesis and increase the need for vasopressor and steroid therapy. The outcome could be worse than in patients given other induction agents.MethodsWe reviewed 159 septic shock patients admitted to our intensive care unit (ICU) over a 40-month period to study the association between induction agent and clinical outcome, including vasopressor, inotrope, and steroid therapy. From our records, we retrieved induction agent use; vasopressor administration at induction; vasopressor, inotrope, and steroid administration in the ICU; and hospital outcome.ResultsHospital mortality was 65%. The numbers of patients given an induction agent were 74, etomidate; 25, propofol; 26, thiopental; 18, other agent; and 16, no agent. Vasopressor, inotrope, or steroid administration and outcome were not related to the induction agent chosen. Corticosteroid therapy given to patients who received etomidate did not affect outcome. Vasopressor therapy was required less frequently and in smaller doses when etomidate was used to induce anaesthesia. We found no evidence that either clinical outcome or therapy was affected when etomidate was used. Etomidate caused less cardiovascular depression than other induction agents in patients with septic shock.ConclusionEtomidate use for critically ill patients should consider all of these issues and not simply the possibility of adrenal suppression, which may not be important when steroid supplements are used.

383 EFFECT OF TIME OF OVULATION INDUCTION BY GONADOTROPIN-RELEASING HORMONE OR PITUITARY LUTEINIZING HORMONE ON OVA/EMBRYO PRODUCTION IN SUPERSTIMULATED BEEF COWS INSEMINATED AT A FIXED TIME

It has been shown than it is possible to AI embryo donors at a fixed time (FTAI) by removing the progestin-releasing device at the time of the last FSH treatment and inducing ovulation with gonadotropin-releasing hormone (GnRH) or porcine luteinizing hormone (pLH) at either 12 h (dairy cows: Bos indicus) or 24 h (beef cows: Bos taurus) after device removal (Bo et al. 2006 Theriogenology 65, 89–101). An experiment was designed to determine the best interval from device removal to GnRH or pLH treatment in Angus (beef cow) donors. Red Angus donors (43 cows and 56 heifers) were blocked by parity and randomly assigned to 1 of 4 treatment groups in a 2 × 2 factorial design. On Day 0, all donors received a DIB vaginal device (Syntex, Buenos Aires, Argentina) plus 2.5 mg estradiol-17β and 50 mg progesterone (P4; Laboratorio Rio de Janeiro, Argentina) IM. Superstimulatory treatments were initiated on Day 4, with a total dose of 320 mg (cows) or 200 mg (heifers) NIH-FSH-P1 of Folltropin-V (Bioniche Animal Health Inc., Belleville, Ontario, Canada) in twice daily IM injections over 4 days. All cows received prostaglandin-F treatment (150 µg d-cloprostenol; Bioprost; Biotay, Buenos Aires, Argentina) on Day 6 (AM and PM); DIB devices were removed with the last Folltropin-V treatment on Day 7 PM. Donors received 0.050 mg GnRH (Lecirelina; Gonasyn; Syntex, Buenos Aires, Argentina) or 25 mg Armour pLH (Lutropin-V; Bioniche) 12 h (Day 8 AM) or 24 h (Day 8 PM) later and were FTAI 12 and 24 h after GnRH or pLH. Ova/embryos were collected nonsurgically and classified according to IETS recommendations on Day 15 AM for donors receiving GnRH or pLH on Day 8 AM and on Day 15 PM for those receiving GnRH or pLH on Day 8 PM. Data were analyzed by two-way ANOVA. Although there was no effect of induction agent (GnRH vs. pLH; P > 0.2) and/or interaction between the induction agent and the time of treatment (P > 0.13) on ova/embryo production, treatment with GnRH or pLH on Day 8 AM (i.e. 12 h after DIB removal) resulted in a significantly lower (P < 0.05) number of fertilized ova and Grades 1 and 2 embryos than treatment on Day 8 PM (i.e. 24 h after DIB removal; Table 1). It was concluded that GnRH and pLH were equally efficacious for inducing ovulation in superstimulated donors that were fixed-time AI. Furthermore, a 24-h interval from progestin device removal to GnRH or pLH administration was preferable for Bos taurus beef donors. Table 1. Ova/embryo production in Angus donors treated with GnRH or pLH 12 or 24 h after removal of a progestin-releasing device and FTAI 12 and 24 h later

The effects of induction agents on mouse convulsions during the recovery period

In the post-operative recovery period, patients are prone to convulsions. A tonic convulsion is a neurological emergency condition. In this study we evaluate the protective effects of intravenous induction agents against convulsions induced by pentylenetetrazol (PTZ) in mice. 174 Caviya parcellus Angora mice were separated randomly into four groups. Induction agents were given via the intravenous route (Midazolam 50 mg kg−1, (42); hypnomidate 3 mg kg−1 (36); thiopentone 25 mg kg−1, (42); propofol 30 mg kg−1, (30). In the control group (24) no induction agent was used. After determining the recovery time by Tail Pinch and Righting reflex, PTZ was administered via the other vein in the tail, tonic-clonic seizures which occurred were evaluated. To determine the mortality rate, we observed the mice for four hours. Groups were compared using the Mann-Whitney U-test. There was no statistical difference in the recovery period between the hypnomidate, thiopentone and propofol groups (P>0.005). PTZ doses that did not cause death by convulsions were induced by 267 mg kg−1 (midazolam) 133 mg kg−1 (hypnomidate) (propofol), 233 mg kg−1 (thiopentone). Time to first convulsions was significantly longer in the midazolam group (P<0.001). The duration of the convulsions was shorter in the midazolam and the thiopentone groups (P<0.005). We conclude that induction of anaesthesia with midazolam or thiopentone may be preferred for patients subject to convulsions.