Effects of a prolonged infusion of fentanyl, with or without atropine, on the minimum alveolar concentration of isoflurane in dogs

Comparison of fentanil or remifentanil prolonged continuous infusion in dogs undergoing elective ovariohysterectomy

“…Opioids typically induce bradycardia by affecting vagal nuclei (REITAN et al, 1978). This bradycardic response can be mitigated by the administration of anticholinergics, with act on M2 muscarinic receptors found in the sinoatrial and atrioventricular nodes (ILKIW et al, 1994;SIMÕES et al, 2016). A canine study evaluating CI of fentanyl at bolus dose of 5 µg/kg and CI of 9 µg/kg/h, either with or without concurrent atropine CI, yielded results akin to those reported in the presented study, resulting in HR reduction of 35% and 43% at 120 and 300 minutes in the fentanyl group, as compared to the group administered both fentanyl and atropine (SIMÕES et al, 2016).…”

“…This bradycardic response can be mitigated by the administration of anticholinergics, with act on M2 muscarinic receptors found in the sinoatrial and atrioventricular nodes (ILKIW et al, 1994;SIMÕES et al, 2016). A canine study evaluating CI of fentanyl at bolus dose of 5 µg/kg and CI of 9 µg/kg/h, either with or without concurrent atropine CI, yielded results akin to those reported in the presented study, resulting in HR reduction of 35% and 43% at 120 and 300 minutes in the fentanyl group, as compared to the group administered both fentanyl and atropine (SIMÕES et al, 2016). Comparable findings were reported in a study assessing the hemodynamic profile of remifentanil in dogs at infusion rates of 9 and 54 µg/kg/h, which led to a decrease in HR of up to 32 bpm (MONTEIRO et al, 2010b).…”

“…This observation might be attributed to the potential release of vasopressin associated with remifentanil infusion, which could serve to mitigate its blood pressure depressant effects (MONTEIRO et al, 2010b). Moreover, opioids have been shown to reduce the vaporization of inhalation agents (MONTEIRO et al, 2010a;SIMÕES et al, 2016), thereby reducing their harmful effects. The administration of fentanyl at rates of 9 and 12 µg/ kg/h resulted in an EtISO of 0.69 V% and 0.3 V%, respectively (SIMÕES et al, 2016); WILLIAMSON et al, 2017).…”

“…Moreover, opioids have been shown to reduce the vaporization of inhalation agents (MONTEIRO et al, 2010a;SIMÕES et al, 2016), thereby reducing their harmful effects. The administration of fentanyl at rates of 9 and 12 µg/ kg/h resulted in an EtISO of 0.69 V% and 0.3 V%, respectively (SIMÕES et al, 2016); WILLIAMSON et al, 2017). Similarly, when remifentanil (18 µg/ kg/h) was administered in female dogs undergoing mastectomy, it was observed 47% of reduction in EtISO (BEIER et al, 2015), consistent with the present study, in which a maximum reduction in isoflurane vaporization of up to 47% and 42% relative to M0 was observed in GF and GR, respectively.…”