Anaesthetic management for caesarean sections in dogs and cats

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.

Feline breeding and pregnancy management: What is normal and when to intervene

Practical relevance:

Cats are common pets worldwide. Successful breeding of cats starts with the selection of suitable breeding animals, and care should be taken to avoid inbreeding. Keeping cats in smaller groups reduces stress and facilitates management.

Clinical challenges:

Breeding cats is challenging in many ways. Group housing is a common scenario, and care should be taken not to have groups that are too large, because of the risk of stress and infectious diseases. Feline pregnancy and parturition both vary in length, which is one reason why it may be challenging to diagnose dystocia. In queens with pyometra, a vaginal discharge may not be evident due to their meticulous cleaning habits.

Audience:

This review is aimed at clinicians in small animal practice, especially those in contact with cat breeders.

Patient group:

Reproductive emergencies occur in both intentionally and unintentionally bred cats, and more often in young or middle-aged queens. Pyometra tends to be a disease of older queens.

Evidence base:

Evidence is poor for many conditions in the breeding queen, and information is extrapolated from the dog or based on case reports and case series.

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.

Maternal and neonatal wellbeing during elective C-section induced with a combination of propofol and dexmedetomidine: How effective is the placental barrier in dogs?

Anaesthetics administered during C-section (CS) can cross the placenta and the foetal blood-brain barrier contributing to distress up to neonatal mortality. Therefore, to prevent neonatal risks, sedatives and analgesics are not commonly administered to the bitch until all pups are delivered. This study aims to evaluate the effect of a new anaesthetic and analgesic protocol for elective CS in dogs, focused on both maternal and neonatal wellbeing. General anaesthesia was induced by a combination of propofol (PPF) and dexmedetomidine (DEX) and maintained with isoflurane. DEX was added to PPF in order to provide analgesia and to reduce PPF dose. Propofol and DEX concentrations in maternal blood, amniotic fluid, and placenta were correlated to maternal and neonatal parameters. Maternal pain score was assessed with Glasgow Composite Measure Pain Scale short-form. Nine healthy purebred dogs scheduled for elective CS delivered 54 pups. The 77.8% of pups were vigorous at birth and assigned to the highest Apgar score (AS). The lowest AS was recorded in pups from mothers receiving additional doses of PPF (p < 0.001). Apgar scores improved with the increase in time between induction and pups' extraction, starting from 30 min after induction (p < 0.01). This study could contribute to clarify the controversy about the optimal extraction's time of pups after induction i.e. the best time between PPF administration and birth. No bitch showed post-operative pain or required additional analgesic doses based on their pain score. Maternal blood PPF and DEX, as well as placental PPF concentrations, decreased over time (p < 0.01). Conversely, placental DEX was fair uniformly detected in littermate pups. Both PPF and DEX were not detectable in amniotic fluid. Placenta resulted an effective barrier against foetal DEX exposure, making this protocol safe, analgesic and advisable for elective CS in dogs.

Neonatal puppy survival after planned caesarean section in the bitch using aglepristone as a primer: A retrospective study on 74 cases

Since most of dystocia end up in caesarean sections (C-sections), the history of any problem during whelping is a good reason to plan in advance a further C-section. Our aim was to confirm that on a large sample and over an extended period of time, mortality in puppies <2 weeks of age was low, born after a planned C-section using aglepristone as a primer. Seventy-four C-sections on 59 different bitches were included. Bitches were monitored during oestrus to estimate the day of ovulation by progesterone assays; 60, 61 or 62 days after ovulation, foetal viability was checked by ultrasonography and progesterone plasma level was measured. None of the bitches was at term (progesterone plasma level >2 ng/ml). An injection of aglepristone was performed in late afternoon to block the effect of progesterone, mimicking its drop at the end of pregnancy. The C-section was conducted the following morning. Twenty-one breeds were represented most of which were bulldogs (26%, 21/74) and Great Danes (16%, 13/74). Four hundred and thirty-five puppies were born. A total of 43/435 puppies died within the first 2 weeks (9.89%). None of the puppies showed any external signs of prematurity. The average number of deaths per litter relative to the date after ovulation was similar (0.5 pups per litter at day 60, 0.7 at day 61, 0.4 at day 62). This study shows that planned C-section after an accurate determination of ovulation and using aglepristone as a primer is a safe procedure for bitches and their offspring. It may be offered to owners if a pregnant bitch is "at risk" of dystocia.

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

OBJECTIVE

To measure plasma methadone concentrations in bitches and the umbilical cords of their puppies after systemic or epidural administration.

STUDY DESIGN

Prospective, randomized, clinical study.

ANIMALS

A total of 27 healthy pregnant female dogs undergoing caesarean section, 4.3 ± 2.3 years of age and weighing 19.9 ± 13.2 kg.

METHODS

The dogs were randomly divided into three groups: 1) intramuscular methadone (0.3 mg kg^-1) (group MET; n = 9); 2) epidural methadone (0.1 mg kg^-1) (group METEPI; n = 9); and 3) epidural lidocaine (4.4 mg kg^-1) [group CON (control group); n = 9]. Ten minutes before induction, methadone was administered intramuscularly to the group MET dogs. Anaesthesia was induced with propofol and maintained with isoflurane. Cardiovascular and respiratory parameters were monitored throughout the anaesthesia. After induction, epidural anaesthesia was administered to dogs in groups METEPI and CON. Before any treatment (T0) and, as soon as the last foetus was removed from the uterus (T1), venous blood samples were collected from each dog into heparinized tubes; the umbilical cords were collected and stored at -80 °C until pharmacological analysis was carried out. The samples were analysed using ultra performance liquid chromatography.

RESULTS

The cardiorespiratory parameters of the bitches and of the puppies at birth, and the Apgar scores did not differ significantly between groups. At T1 both the median maternal methadone plasma concentration and the median methadone umbilical cord concentration were higher in group MET compared to group METEPI (p = 0.0018 and p = 0.004, respectively). The maternal plasma concentration was higher than the concentration in the umbilical cords (p = 0.05) in group METEPI but not in group MET (p = 0.25).

CONCLUSIONS AND CLINICAL RELEVANCE

Epidural methadone (0.1 mg kg^-1) administered to bitches undergoing caesarean section is associated with lower umbilical cord methadone concentrations as compared with intramuscularly administered methadone at higher dosages (0.3 mg kg^-1).