Vet360 Vol 4 Issue 4 August 2017 Vet 360 - Page 20

CPD ACCREDITED ARTICLE done at 15 minutes and 60 minutes after delivery 26,27,69 . This may be because more time was allowed to elapse for removal of depressive effects of the anaes- thetic agents before an Apgar score was evaluated. In the current study the delay from delivery till Apgar score evaluation may have allowed for complete re- versal of medetomidine in the puppy and for the con- centration of propofol in the central nervous system to diminish by redistribution which is reported to take 15 to 20 min 8,72 . Furthermore, the low induction dose of propofol used and atipamezole administration, may also have favourably influenced Apgar scores. In agreement with the studies by others 27,26 , the cur- rent study shows that Apgar scores correlate with mortality, with lower scores being associated with higher mortality rates. Although another study has shown that English Bulldog puppies were at increased risk compared to other breeds for suffering from poor vigour after CS 11 , our study showed only slightly re- duced Apgar scores when compared to other pure- breds and Boerboel puppies. The method of delivery may impact puppy vigour. In contrast to findings by others, we recorded higher Apgar scores for puppies from caesarean deliveries than those of the eutocic vaginally delivered puppies reported in the literature 73,74 . These differences may reflect the different anaes- thetic protocols used in the studies and the timing of obstetric intervention. Our results show that me- detomidine appeared not to have affected the Apgar score. The effect of early intervention by CS (at the first ob- servation of a dilated cervix), prior to foetal compro- mise may in part explain the good results obtained in our study. This agrees with the literature reporting positive correlation between timeous intervention and puppy survival 12,21,75-81 Conclusions This study shows that anaesthetic protocol using medetomidine hydrochloride at 7 µg/kg iv as pre- medicant combined with 1 to 2 mg/kg propofol as induction agent and 2% sevoflurane in oxygen as maintenance, is safe for CS in the bitch. The Apgar scores 15 min after delivery, as well as the puppy and maternal survival rates at delivery, 2h and 7d compare favourably to those reported in publications using other anaesthetic protocols. The use of medetomi- dine as premedicant permits the use of less than half the induction dose of propofol usually required when no premedicant is used. Practical hints The primary author has been using medetomidine in more than 2000 CSs and in bitches of all sizes. The weight (real mass not lean body mass) of the bitch requires discussion. In this study, all anaesthetic subjects were 20kg or more. It is however the experience of the primary author when using medetomidine at 7 µg/kg for CSs in toy breeds, the dose of propofol required to allow intubation approaches 2-3 mg/kg as opposed to 1-2 mg/kg. Furthermore, the time allowed following in- duction and intubation in the prep room whilst not on gas inhalation, is reduced when using medetomi- dine at the low dose of 7 µg/kg. Therefore, the author uses 10 µg/kg medetomidine premedication for CS in dogs under 20 kg with no observable differences in outcome. Not all practices perform CSs frequently and many may not have sufficient experienced staff to ensure rapid surgical preparation and neither do all prep rooms have access to gas-inhalation anaesthe- sia. Therefore, if delays between intubation and con- nection to gas-inhalation maintenance of anaesthesia are expected, the author advises using medetomidine premedication at 10 µg/kg irrespective of the weight of the bitch and has observed no differences in out- come when doing so. Practitioners are reminded that propofol is available in 1% and 2% concentrations and should make sure that they adjust their volumes ac- cordingly. The question whether a bitch should be surgically prepped prior to premedication, after premedication or after premedication, induction and intubation is not straight forward. Some bitches are combative and will resist the restrai ЁɕեɕѼəɴɝɕ)ɅѥM٥ɕЁэ́䁉ɕ)ѡЁɔͅɕյ䁑ͅɅєݡ)͠ձ́ՙɥɽɅ单)Սѥٔ݅幑ɽ =L͕ٕɕ䁑ͅɅє)ݡͼչՉ͡ф ɅȤȴ)ѡɵɔ٥ɕЁэ́ՙɥɽ) =Lѡɕѥѡ݅䁥Սɔ)ѥ͕͕ٕ́ɔͅɅѥ٥ͥ兹)̤ٕͥѡѥЁѡЁ́Ёɕ)ѡхȁͥѥͥѥչՉ͡є) ɅȤ ͔ЁЁ݅́ɕѕ)܁эݥɕѼɕɅЁ͔)Չхѥɽѥ Ḿɔəɵ)Ʌ单э̰ѡɥѡȁɕ́Ѽ)ɝɕɔэ́ݥՍѥ)Չѥ)QٽյѡѽЁѡ͕́)͍ɥѡ́ȁ́͵ѡɕɔɅє)ɕЁѡɕեɕٽյɔɕ)䁵ݡͥāɥͼݡͥ)ٕ͵ٽյ́ѽ䁉ɕ̰ͥЁٽյ)ѽ䁉ЁѡՈѡ)Ʌٕ́ѡѕȁѡѥѡɥ)ѡɕɔѕѡѽٽյݥѠ)ɥ́ȁͅ䁕ɔɅѥѡձ)ɕեɕٽյAɅѥѥ́䁉ѕѕѼ͔)ѡѽɅ͍ձɱ䁥ɕͥٔэ)́Ѽ܁ȁѡЁɅٕ́Ѡ)ѕȸY䁱ɝ͕́ѽɔɕեɕ)Ʌ͍ձɱѼٔѡ́ѡ́Ʌѥ)Ё٥͕́́ͅ䁡́Ёх)͡)II9 Lمܹٕٕѱ)ٕ)%ՔЁUUMP܁