Evaluation of methadone concentrations in bitches and in umbilical cords after epidural or systemic administration for caesarean section: A randomized trial

The influence of anaesthesia drugs on puppy vitality after caesarean section: a systematic review

OBJECTIVE

To review and systematically analyse the literature describing the effects of anaesthesia drugs on puppy vitality scores or survival in dogs undergoing caesarean section.

ANIMALS

Overall 13 randomized controlled trials (RCTs) involving 1978 puppies were included.

METHODS

A comprehensive search using PubMed, Embase and Scopus databases was performed from 1970 until September 2024 to obtain nonrandomized and RCTs examining the effects of anaesthetics on puppy survival rates or vitality scores after caesarean section in dogs. Only studies in English were screened. Search terms included: 'c-section' or 'caesarean section' and 'anaesthesia' and 'dog'. Two authors independently searched, classified and extracted the data. Studies were included if they evaluated the effects of anaesthesia drugs in dogs undergoing general anaesthesia and puppy survival or vitality scores. The level of evidence was scored according to the Oxford Centre for Evidence-based Medicine criteria, and a modified criterion score was used to assess the risk of bias based on the SYRCLE risk of bias tool and the SIGN checklists.

RESULTS

Methodological characteristics varied considerably between studies, including drug doses, titration of anaesthetics, anaesthesia monitoring and puppy outcome scores. Ten studies assessed puppy vitality by using a modified Apgar score (AS). A high risk of bias was identified in six studies, whereas three had a low risk of bias. The scarcity of methodologically consistent studies and the quality of data limit identification of an optimal anaesthetic regimen to improve puppy survival. Low doses of morphine, methadone, dexmedetomidine or meloxicam preoperatively did not produce a significant impact on puppy vitality. Ketamine-midazolam, etomidate or thiopental appear to worsen immediate neonatal outcomes. No difference in neonatal survival was found between alfaxalone and propofol, but AS were higher with alfaxalone than with propofol immediately after birth.

CONCLUSIONS

The use of injectable anaesthetics for maintenance of anaesthesia led to lower puppy vitality.

Retrospective evaluation of the induction of anaesthesia with alfaxalone or propofol in cats undergoing caesarean section

OBJECTIVES

Several anaesthetic protocols for caesarean section (c-section) have been described in dogs; however, anaesthesiological studies in cats undergoing c-section are lacking. The aim of this study was to assess the viability and outcome of kittens born from queens undergoing emergency c-section and receiving propofol or alfaxalone for anaesthetic induction and isoflurane for maintenance of general anaesthesia.

METHODS

All cats admitted to the Veterinary Teaching Hospital of the University of Bologna between January 2014 and December 2022 for dystocia that had undergone an emergency c-section were analysed in this retrospective study. The queens received propofol 2-6 mg/kg IV (group P) or alfaxalone 1-3 mg/kg IV (group A) administered slowly; general anaesthesia was maintained with isoflurane. Survival of all the kittens was evaluated at birth and after 24 h; in addition, heart rate, respiratory rate and mucous membrane colour were evaluated in the kittens at birth.

RESULTS

Of the 14 cats included in the study, eight received alfaxalone (group A) and six received propofol (group P) for induction of the general anaesthesia. A total of 50 kittens were born by c-section: 30 kittens in group A and 20 in group P. The overall survival of the kittens was 90% at birth: 96.7% (29/30) for group A and 80% (16/20) for group P. The 24 h survival rate was 93.1% for group A and 87.5% for group P.

CONCLUSIONS AND RELEVANCE

The results of the present study demonstrated that in cats undergoing c-section, both alfaxalone and propofol are feasible for the induction of general anaesthesia.

Maternal and neonatal effects of epidural levobupivacaine combined with fentanyl or sufentanil for elective cesarean-section in brachycephalic breeds

The aim of this study was to compare the safety and clinical efficacy of epidural levobupivacaine combined with fentanyl or sufentanil for bitches undergoing elective cesarean-section and the impact of these anesthetic protocols on neonatal viability. The anesthetic protocol consisted of intramuscular morphine (0.2 mg/kg), followed by an intravenous bolus of propofol, in a dose sufficient to allowed the puncture of the lumbosacral space. The dogs were randomly allocated to receive 0.5 % levobupivacaine plus fentanyl (2.5 µg/kg; LF: n = 9) or sufentanil (1 µg/kg; LS; n = 11). Maternal cardiorespiratory parameters were monitored at specific time points during surgery. Intraoperative propofol supplementation was based on the presence of head and/or thoracic limb movements. Neonatal reflex responses and the Apgar score (range 0-10 points) were assessed at 5 and 60 minutes after birth. Puppy mortality rate was recorded until 24 hours after birth. Data were analyzed using two-way ANOVA, Tukey's test, Wilcoxon signed rank test, and Fisher's exact test (P < 0.05). Intraoperatively, maternal cardiorespiratory variables and propofol requirements were similar between groups, with no detection of anesthetic complications. The puppy reflex responses did not differ between groups at any time point. The medians (range) of Apgar scores were lower (P = 0.016) in the LF [5 (1-9)] at 5 minutes in comparison with LS [6 (2-9)], while no intergroup differences were recorded at 60 minutes [LF = 8 (2-10); LS = 9 (6-10]. The total mortality rate was 4.1 %. In the LS group, no puppies died, while in the LF 8 % of the puppies died in the first 24 hours after birth (P = 0.11). Epidural levobupivacaine combined with fentanyl or sufentanil provided minimal maternal and neonatal adverse effects, but neither protocol enabled the performance of a C-section in 100 % of the French and English bulldogs, without propofol supplementation.

Parturition in Mammals: Animal Models, Pain and Distress

Parturition is a complex physiological process and involves many hormonal, morphological, physiological, and behavioural changes. Labour is a crucial moment for numerous species and is usually the most painful experience in females. Contrary to the extensive research in humans, there are limited pain studies associated with the birth process in domestic animals. Nonetheless, awareness of parturition has increased among the public, owners, and the scientific community during recent years. Dystocia is a significant factor that increases the level of parturition pain. It is considered less common in polytocous species because newborns' number and small size might lead to the belief that the parturition process is less painful than in monotocous animal species and humans. This review aims to provide elements of the current knowledge about human labour pain (monotocous species), the relevant contribution of the rat model to human labour pain, and the current clinical and experimental knowledge of parturition pain mechanisms in domestic animals that support the fact that domestic polytocous species also experience pain. Moreover, both for women and domestic animal species, parturition's pain represents a potential welfare concern, and information on pain indicators and the appropriate analgesic therapy are discussed.