Comparison of the safety of alfaxalone and propofol as anaesthetic induction agents in bitches undergoing c-section

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The evidence
Six studies in total were found relevant to the PICO, including four randomised controlled trials ( No exclusions were made for breed, parity, urgency or whether any pups had been born naturally prior to presentation. The mean age for alfaxalone group was 48.9 ± 21.4 months. The mean age for the propofol group was 58.3 ± 18.1 months.

Sample size: 74 bitches
Intervention details: Cases were randomised in blocks of three so that two in three would receive alfaxalone induction and one in three would receive propofol induction: 1. Alfaxalone induction n = 48/74 (65%) 2. Propofol induction n = 26/74 (35%) Experimental details:  Before anaesthesia was induced, the clinical status of each patient was determined by physical examination.
Ultrasonographic examination of the bitch was performed. Venous blood samples for haematology and biochemistry were collected immediately prior to induction.  No patients received a premedication.  Patients in the alfaxalone group received an induction volume equalling 2 mg/kg body weight intravenously (IV).  Patients in the propofol group received an induction volume equalling 7 mg/kg body weight IV.  The dose was administered until the investigator determined the depth of anaesthesia to be sufficient for endotracheal intubation or until the whole dose had been administered over 60 seconds. If intubation was not possible 60 seconds after the induction dose was given, one further induction dose could be administered to effect. Mean induction dose for the alfaxalone group was 1.87 ± 0.39 mg/kg and for the propofol group was 5.46 ± 1.05 mg/kg.  The quality of induction, maintenance and recovery was assessed in each patient. Apnoea during maintenance was recorded if more than 30 seconds occurred between inspirations.  General anaesthesia was maintained in all patients using inhalational isoflurane and oxygen.  Respiratory rate, pulse rate and oxygen saturation of haemoglobin were recorded during the procedure and assigned to one of three time categories: after induction, during the anaesthesia and during the recovery phase.  Following delivery of the pups, local anaesthesia, analgesia, anti-emetics, antibiotics, procoagulants and tocomimetics were administered as indicated by the needs of the bitch and the preference of each investigator.  As soon as possible after delivery, each pup was assessed as live or dead. Each live pup was then scored as positive or negative for withdrawal reflex, sucking reflex, anogenital response and flexion reflex.
 At 24 hours after delivery, each pup was reassessed as live or dead.
Study design: Prospective, non-blinded, randomised, positive controlled trial Outcome studied: 1. Quality of anaesthetic induction, maintenance and recovery in the subjects. This was measured as percentage of bitches in which apnoea was recorded and by a subjective scoring system as described by Ko et al. (1998 .35) did not differ between the alfaxalone and propofol group respectively (P = 0.5, 0.9, 0.6 and 0.8). • The alfaxalone group puppy survival percentages at birth did not differ from those in the propofol group (93% vs 94% respectively; P = 0.7). • The alfaxalone group puppy survival percentages at 24 hours did not differ from those in the propofol group (89% vs 89% respectively; P = 0.9).  There was no effect detected of treatment group on the total number of deaths (P = 0.7).

Limitations:
 Not blinded.  The number of brachycephalic bitches (12/26) in the propofol group was recorded as 25% of the population. It truly represents 46% of the propofol population.  9/48 (19%) of the alfaxalone group were represented by brachycephalic breeds whereas 12/26 (46%) of the propofol group was represented by the same. Brachycephalic breeds tend to be more unstable under anaesthesia (Gaynor et al., 1999) so this difference in demographics may have affected anaesthetic scores.  This study was carried out between four different locations with seven different veterinary surgeons in total, which may have had an effect particularly on scoring anaesthetic quality due to its subjective measurement. However, the use of a scoring system (Ko et al., 1998) will have reduced the amount of inter-investigator variation.  Apnoea was recorded in six bitches during anaesthetic maintenance but the duration of this apnoea was only recorded on one occasion possibly impacting scores for quality of anaesthesia.  Withholding of analgesics and local anaesthetics may have affected the quality scores for anaesthetic maintenance and recovery.  The propofol sample size was half the size of the alfaxalone sample size.  No analysis of respiratory rates, pulse rates, oxygen saturations and rectal temperatures.

Doebeli et al. (2013)
Population: Bitches presenting with dystocia for which caesarean section was indicated and the puppies born to them. Mean age of the bitches was 3 years, ranging from 1 to 11 years. Mean body weight of the bitches was 7.3 kg, ranging from 1.6 to 51 kg.

Sample size: 22 bitches 81 puppies
Intervention details: Cases divided in half between those receiving alfaxalone induction and those receiving propofol induction: 1. Alfaxalone group n=11 (50%) 2. Propofol group n=11 (50%) Experimental Details:  All bitches received IV fluids (Lactated Ringer's solution, 10-20 mL/kg/h) immediately after presentation until after recovery. In those bitches with poor general condition or severe dehydration, HAES-steril 10% was added (1-2 mL/kg/h).  Before induction, all bitches were preoxygenated for 5 minutes using flow by oxygen at 2 L/minute and received a 20 mg/kg IV dose of cefazolin.  Bitches in the alfaxalone group received an induction volume equaling 1-2 mg/kg body weight IV.  Bitches in the propofol group received an induction volume equaling 2-6 mg/kg body weight IV.  The surgeons and the observer who performed the evaluations after anaesthesia induction were blind to the agent used.  Anaesthesia maintained using isoflurane to effect.  Immediately after the last puppy was delivered, all bitches were started on 5 mcg/kg/h continuous rate infusion of fentanyl.  All bitches received 14 mcg/kg buprenorphine and 4 mg/kg carprofen IV 20 minutes before the end of surgery.  After delivery, all puppies had fluid cleared from the upper airways using suctioning. They were actively warmed and were oxygenated using flow by oxygen at 2 L/m. If breathing was inadequate, Respirot was given at a dose of 1-2 drops orally and 3-5 mL/100g 5% glucose was given subcutaneously.  Body weight was recorded and a clinical examination of each puppy was performed. Outcome studied: 1. Neonatal viability determined using a modified Apgar score developed by Veronesi et al. (2009) at 5, 15 and 60 minutes after delivery. Heart rate, respiratory effort, reflex irritability, motility and mucous membrane colour were rated 0 (absent), 1 (detectable, weak) or 2 (detectable, strong). 2. Puppy survival measured as percentage alive at birth, 60 minutes, 24 hours, 3 days and 3 months after. 3. Pre and intra-operative parameters in bitches including temperature, heart rate, respiratory rate, packed cell volume (PCV), total protein, anaesthesia duration, mean blood pressure and delivery time.

Main findings: (relevant to PICO question):
 Puppy survival did not differ between the alfaxalone and the propofol group at any of the measured time intervals.  4 puppies from each group were born dead over the course of the study.  At the first assessment 5 minutes after birth, the proportion of puppies in the alfaxalone group (N = 36) with high (7-10), medium (4-6) and low (0-3) Apgar scores were 68%, 15% and 17% respectively. The same proportions for the propofol group (N = 45) were 19%, 31% and 50% respectively.  The Apgar scores at 5, 15 and 60 minutes after delivery were greater in the alfaxalone group than in the propofol group. The overall estimated score difference between the groups was 3.3 (P<0.001).  Pre and intra-operative parameters did not differ between the alfaxalone and the propofol group. Maternal recovery was uneventful and rapid in both groups.

Limitations:
 A rather small sample size was used. Although a significant difference in Apgar scores was found between the alfaxalone and propofol groups, a larger population may provide better information on the range of patients seen in practice.  Ranges were given for alfaxalone and propofol induction dose but no indication as to how doses were chosen.  No indication as to how patients were distributed between study groups.  Although the authors report maternal recovery as uneventful and rapid, no values are provided with regards to recovery time.  The value of Apgar scores in predicting short-term survival of puppies is not fully known.

Vilar et al. (2018)
Population: Bitches undergoing elective caesarean section. 2. Group PS: propofol induction, sevoflurane maintenance (n = 14) 3. Group PES: propofol induction and maintenance, lidocaine epidural analgesia (n = 14) • All bitches premedicated with morphine (0.2 mg/kg) ten minutes before induction with 3 mg/kg propofol. • Bitches in group P were taken straight to surgery and maintained on repeated boluses of propofol. Once the last neonate was removed, maintenance was swapped to sevoflurane (0-8%) in oxygen. • Bitches in group PS were intubated following induction and maintained on sevoflurane (0-8%). • Bitches in group PES were intubated and then epidural anaesthesia was performed using lidocaine (2%) into the lumbosacral intervertebral space. Once the last neonate was removed, maintenance was swapped to sevoflurane (0-8%) in oxygen. • Intramuscular tramadol and postoperative oral amoxicillin plus clavulanic acid was given to all patients. In all groups 1-2 mcg/kg fentanyl IV was provided when required to manage intraoperative pain. • Once the bitch was transferred to the surgical area, heart rate, respiratory rate, oxygen saturation, rectal temperature and blood pressure were monitored every 5 minutes. • At 60 and 120 minutes after surgery, it was assessed whether the female was conscious, able to get up and/or walk and accept the puppies. • Immediately following delivery, the puppies were evaluated and Apgar scored using a modified Apgar score model (Batista et al., 2014). Puppies with an Apgar score < 5 were provided with neonatal resuscitation protocols. • Puppies were classified as born dead, born alive but with severe defects, born alive but dead within 6h or viable and still alive after 6h. Neonatal viability was also assessed at 12, 24 and 48h after birth.

Study design: Non-blinded, randomised controlled trial
Outcome studied: 1. Intra and postoperative parameters in bitches including heart rate, respiratory rate, oxygen saturation, rectal temperature, consciousness, ability to get up and/or walk and accept the puppies. 2. Anaesthetic variables in bitches including number of propofol boluses required, time taken to start surgery following intubation and sevoflurane concentration required intraoperatively. 3. Puppy survival measured as percentage alive at birth and percentage mortality after 12 hours and 48 hours. 4. Puppy vitality measured via a modified Apgar scoring system (Batista et al., 2014) at birth and 60 minutes after. Numbers of neonates requiring neonatal resuscitation was also recorded. The PS group is the only group in this study satisfying my inclusion/exclusion criteria and are therefore the only findings included here.
• Mean values of parameters measured between the beginning of inhalatory anaesthesia and the end of surgery in the PS group were: o Drugs administration -6/51 (11.7%)

Limitations:
 Not blinded.  Comparisons drawn between groups are not relevant for the purposes of this review.  Bitches were premedicated with morphine which may have affected puppy vitality.  Brachycephalics were heavily represented, however this may correlate with the relevant clinical population.  A scoring system for the quality of anaesthesia experienced by the bitches may have been useful, for example that described by Ko et al. (1998).  Results were not provided for some of the parameters measured in the bitchesconsciousness, ability to get up and/or walk and accept the puppies.  It would be useful to know the longer term outcome of the puppies, for example over a few weeks or months.

De Cramer et al. (2017)
Population: Bitches selected from the general obstetric population as being at increased obstetric risk. p a g e | 10 of 23  Bitches were admitted 3-4 days prior to predicted parturition date (calculated as day 57 following day 0 of pregnancy). In these days bitches were observed for signs of impending parturition and by 6 hourly vaginal speculum examinations of the cervix.  The decision on when to perform a caesarean section was based upon the first appearance of any dilation of the cervix.  Medetomidine was given as a predmedicant at 7 mcg/kg IV.  Induction performed 1 minute later with a 1 mg/kg IV bolus of propofol. Top ups were given if required up to 2 mg/kg total.  Patients were intubated immediately after induction but were not connected to a closed circuit until surgical preparation had been carried out (averaging 3-5 minutes).  All bitches were given a set amount of lactated ringers commencing following induction and finishing when 35 mLl/kg had been infused.  10 mg/kg cefazolin was administered IV at induction.
Antibiotics were continued postoperatively with 20 mg/kg BID oral amoxicillin for 5 days. 0.1 mg/kg meloxicam was administered IV only when the last puppy had been removed.  Following removal of the puppies, atipamezole hydrochloride was given subcutaneously (SC) to each puppy at the dose of 50 mcg/puppy. 10% povidone iodine was applied to the umbilicus. Puppies were dried, fluid was shaken from the airways and they were placed in an incubator set at 35°C.  After surgery 20 mcg/kg atipamezole hydrochloride was administered IV to the bitch.  It was recorded whether the bitches were fully ambulatory at 15 minutes following extubation.  After delivery of the puppies, records were made of total puppies delivered, live, dead, deformed and euthanised.  Apgar scores were assessed 15 minutes after delivery of the last puppies using the system described by Veronesi  and other purebreed puppies respectively was 9.77, 9.35 and 9.68.  2 hour survival rate was negatively correlated with the proportion of puppies in a litter with Apgar scores of 8 or below (P = 0.01) but was not correlated to the mean Apgar score of litters (P = 0.11).  Maternal survival rate was 291/292 with one Boerboel bitch dying from gastric dilation and volvulus 2 days following surgery.  The average GCPS for bitches at discharge was 6.4.  No bitch had a haematocrit of below 30% after surgery.  All bitches were fully ambulatory 15 minutes after extubation.

Limitations:
 Non-comparative study therefore hard to assess how a different protocol may compare under the same conditions.  There was little measurement of the safety of anaesthesia for bitch. Although number of bitches ambulatory at 15 minutes gives some indication of recovery, it would be useful to know intraoperative parameters or to use an anaesthetic scoring system.  It could be useful to include GCPS following recovery as well as at discharge.  The pain score at discharge is presented as an average score of all bitches included in the study. This is broad and is not particularly useful in knowing if bitches who underwent a more complicated anaesthesia were more painful postoperatively for example.  The population in this study was made predominantly of two breeds which is not representative of the full clinical population. However, English bulldogs are commonly among those presenting for caesarean section.  All caesarean sections in this study were elective and results may differ to animals undergoing an emergency surgery.  The medetomidine premedication may contribute to changes in puppy vitality.  Puppies given SC atipamezole prior to Apgar scoring. Sample size: 141 bitches -age ranged from 13 months to 9 years and represented 60 breeds. 412 puppies.

Veterinary Evidence
Intervention details:  The veterinary surgeon on duty determined when caesarean section was indicated and performed the surgery. In some cases, puppies had been delivered per vaginum prior to caesarean section.  Anaesthesia was induced using propofol given IV to effect. 6.5 mg/kg was drawn up. Estimated weight of the puppies was deducted from the bitch's weight before calculating this dose. 20 minutes was allowed to elapse following induction before delivery of the puppies was begun.  Patients were immediately intubated and maintained using gaseous isoflurane (0.5 -2.0%) in a mixture of 65:35 oxygen:nitrous oxide.  Immediately after delivery, each puppy's nasal passages, mouth and pharynx were cleared of mucus. Puppies were also gently swung to remove fluid.  In some puppies, a combination of crotethamide and cropropamide were given orally (2 -12 mg of each drug).  Viability of puppies were monitored during a period of 1-3 hours until bitches and puppies were discharged.  Postoperative condition of the bitches and puppies were determined by telephone interview of owners 3 months after caesarean section.

Study design: Non-comparative study
Outcome studied: 1. Status of the bitchesduring anaesthesia and in recovery, whether they could care for their puppies postoperatively and complications encountered. 2. Puppy survival measured as percentage born alive and percentage alive after the 3 month observation period. 3. Puppy vitality by looking at how many puppies required more active resuscitation than usual.

Bitches
 Induction and maintenance of anaesthesia was uneventful in all bitches.  Bitches recovered quickly from anaesthesia and without excitation.  101/141 of the bitches were considered by the owners to be alert and were unaffected by the anaesthesia. The other 40 were lethargic for 1-2 days after surgery.  One brachycephalic bitch developed dyspnoea after surgery and a tracheotomy was performed following extubation. It subsequently recovered.  One bitch had aggressive behaviour toward her puppies and was unwilling to care for them for 2 days after surgery. She then cared for them but had less interest than was considered normal. Her milk production was also insufficient.  One bitch developed metritis and mastitis 24 hours after surgery.  Two bitches developed metritis within 1 week of surgery and another developed mastitis 4 weeks after surgery.  Also after surgery, two bitches had slight bleeding, one had peritonitis and diarrhoea and another had diarrhoea and dehydration.
Puppies  74% (306/412) puppies delivered by caesarean section were born alive (26% (106/412) puppies delivered by caesarean section were stillborn).  4% (13/306) of puppies born alive died within 20 minutes.  Of the 293 surviving puppies, 36 (12%) were euthanised or died during the 3 month postoperative period.  Most puppies had evidence of some respiratory depression and required more active resuscitation.  The degree of respiratory depression did not differ between the first and last puppy delivered during each caesarean section.

Limitations:
 Non-comparative study therefore hard to assess how a different protocol may compare under the same conditions.  Several vets were involved in performing the caesarean sections and accompanying anaesthesia.  There were no values given relating to how many puppies needed more active resuscitation.  There was no indication of what measurements were used when determining if bitches had a good anaesthetic induction, maintenance and recovery.  The follow-up was done by telephone communication. It may not be reliable to count on owners to give an accurate assessment of their animals.  In some cases variable numbers of puppies had been removed from the uterus before caesarean section and in others none had.  Some puppies were given crotethamide and cropropamide if required and others were not which may influence mortality over the course of the study.

Luna et al. (2004)
Population: Healthy 2-5 year old bitches requiring caesarean section due to lack of uterine contractions or inadequate vaginal dilation. Bitches weighed between 7 and 14 kg.

Sample size: 24 bitches
Intervention details: Bitches divided into four groups:  Experimental details: • All bitches sedated with 0.5 mg/kg chlorpromazine IV.
• Groups 1-3 were given their induction and then immediately intubated and given gaseous enflurane maintenance anaesthesia. • Group 4 underwent epidural anaesthesia at the lumbosacral space and were not intubated. • 10 mL/kg/hr lactated Ringer's solution infused into all bitches during the anaesthetic. • Equal numbers of each group were operated on by one of two experienced veterinary surgeons. • Following removal from the uterus, the airways of the neonates were cleared and the following measurements were recorded: heart and respiratory rates, rectal temperature and neurological reflexes (including pain reflex, suction reflex, anogenital reflex, magnum reflex and flexion reflex).  The puppies were examined 7 days later and the numbers which had died were recorded.

Study design: Non-blinded randomised controlled trial
Outcome studied: 1. Puppy vitality measured using various parameters including heart and respiratory rate, temperature, and presence or absence of the reflexes mentioned above. 2. Puppy mortality.

Main findings: (relevant to PICO question):
The only group relevant to this evidence summary is the propofol induction group and are therefore the only results included here. The following was found in this group: • Mean values for heart and respiratory rate of the puppies were 123 beats/minute and 16 breaths/minute respectively. • Mortality was 1/24 puppies (4%). • The percentage of puppies testing positive for each of the reflexes tested was as follows: Limitations:  Not blinded.  The epidural group does not utilise inhalational anaesthesia, making it difficult to draw comparisons to the other groups.  Narrow weight range of dogs (7-14 kg) may not be representative of a clinical population.  Small sample sizes for each group.  Cases were divided between two veterinary surgeons. However, cases in each group were divided equally and each veterinary surgeon was described as experienced.  Although the paper was primarily focused on the effects on the puppies, it may have been useful to record parameters in the bitches to better evaluate the safety of the protocols on them too.  No follow-up of puppy vitality/mortality following the initial measurements. Safety of anaesthesia can be defined in many different ways and in the case of caesarean sections, relates to both the bitches and the puppies individually; I will therefore consider each of these in turn.

Maternal Safety
With regards to the bitches, perioperative mortality is one potential measure of safety. However, there was a single bitch mortality in only one of the studies (De Cramer et al., 2017), which was a gastric dilation 2 days postoperatively, likely unrelated to the anaesthesia. The relatively small sample sizes used by most of the studies make it difficult to assess differences in mortality between a propofol and alfaxalone induction. In a study by Moon et al. (1998) of 808 bitches undergoing caesarean section, a maternal mortality rate of 1% (n=9) was found. We can therefore see that differences in mortality may not be apparent with the sample sizes used in these studies. Five of the studies attempted in some way to measure the effect of the anaesthetic protocol on the bitches intraoperatively and postoperatively (Metcalfe et al., 2014;Doebeli et al., 2013;Vilar et al., 2018;De Cramer et al., 2017;and Funkquist et al., 1997). One study using propofol (Funkquist et al., 1997) subjectively assessed the status of the bitches, reporting induction and maintenance of anaesthesia to be uneventful in all cases. They also found that 101/141 of the bitches were considered by the owners to be alert and unaffected by the anaesthesia in the 1-2 days following surgery. One brachycephalic bitch developed dyspnoea postoperatively which may be related to the anaesthetic protocol, however this probably falls in line with the expected anaesthetic risks in brachycephalic dogs (Gaynor et al., 1999). Low numbers of other postoperative complications were seen in this study, all of which were unlikely to be related to the anaesthesia. Three studies recorded objective variables pre, intra or postoperatively. De Cramer et al. (2017), one of the propofol studies, found a maternal survival rate of 291/292, with the death due to a gastric dilation and volvulus 2 days postoperatively which is unlikely to be related to the anaesthesia. All bitches were ambulatory 15 minutes after extubation and no bitches had a haematocrit below 30% following the surgery. Average pain score at discharge was 6.4 which is on the boundary of requiring further pain relief but is probably to be expected following abdominal surgery. Vilar et al. (2018), one of the propofol studies, recorded heart rate, respiratory rate, oxygen saturation, rectal temperature, consciousness, ability to get up and/or walk and accept the puppies. Only results for heart rate, respiratory rate, oxygen saturation and rectal temperature were reported and there were no adverse findings. In the comparison study by Doebeli et al. (2013) temperature, heart rate, respiratory rate, PCV, total protein, anaesthesia duration, mean blood pressure and delivery time were recorded. No differences were found between the propofol and the alfaxalone group. Although reporting objective variables such as in these three studies is useful, I believe an anaesthetic scoring system such as that used in the study by Metcalfe et al. (2014) to be much more useful at deciding the quality of anaesthesia undergone by the patient. The scoring system in this study was described by Ko et al. (1998). They found that of bitches in the alfaxalone group, 47 (98%), 39 (81%) and 35 (73%) scored a top score for induction, anaesthetic effectiveness and recovery respectively. For the same parameters with propofol, 23 (88%), 17 (65%) and 18 (69%) scored top scores, lower in every category when compared to the alfaxalone group. Also in this study, induction apnoea was recorded in 15% of bitches in the alfaxalone group compared to 25% of bitches in the propofol group. Maintenance apnoea was recorded in 4% of bitches in the alfaxalone group compared to 17% of bitches in the propofol group. Although these values differ, the sample sizes may be too low to draw meaningful conclusions.
From these studies, very few anaesthetic complications were encountered, highlighting that with regards to the bitches, both propofol and alfaxalone are relatively safe to use. This is the conclusion found by the two randomised controlled trials (Metcalfe et al., 2014;and Doebeli et al., 2013) which are the most reliable studies to consider when answering this question. The only real differences between the two induction agents was found by Metcalfe et al. (2014), with the anaesthetic scoring system suggesting that patients induced using alfaxalone may have a slightly better quality of anaesthesia than those induced using propofol. The differences in the numbers of bitches experiencing apnoea in each of the groups may be relevant as both alfaxalone and propofol can cause respiratory depression. However, we probably can't draw conclusions about this from this study alone so further investigation with larger sample sizes may be required to see if apnoea is more apparent using either induction agent.

Puppy Safety
All six studies looked at two major variables when assessing safety of the anaesthesia relating to the puppiespuppy survival, which is directly comparable between studies, and puppy vitality, which each study assessed in different ways. In the four studies including a propofol but not an alfaxalone experimental group ( The two randomised controlled trials (Metcalfe et al., 2014;and Doebeli et al., 2013) found no significant difference in the puppy survival between the alfaxalone and propofol groups at birth (93% vs 94% respectively; P = 0.7) or at 24 hours after (89% vs 89% respectively; P = 0.9). In light of the strength of evidence of the other papers, these studies are more reliable, indicating that alfaxalone and propofol probably have similar effects regarding puppy mortality. Perioperative puppy mortality in the propofol groups of the other studies ranged from 1.  (Funkquist et al., 1997) found a much higher puppy mortality rate than in any of the others and when discounting this study puppy mortality would range from 1.79-5.7%. Therefore, puppy mortalities when undergoing a propofol induction fell within acceptable limits for a majority of the studies evaluated.
Nevertheless, it is difficult to use these values in context when comparing the two induction agents due to large differences in study protocols and populations. We are therefore best drawing conclusions from the two randomised controlled trials directly comparing alfaxalone and propofol, which found that both agents perform similarly with regards to puppy mortality perioperatively.
Puppy vitality is harder to quantify and compare between groups. , we can be more certain that propofol is safe for this purpose. However, current evidence suggests that alfaxalone is a safe alternative and further research with regards to its use will increase certainty of this.
The most reliable studies from those I found, the two randomised controlled trials (Metcalfe et al., 2014;and Doebeli et al., 2013), suggested that there may be small differences between the safety of alfaxalone and propofol inductions in bitches undergoing caesarean section, both for the bitches and the puppies. There is evidence to suggest that alfaxalone may provide a slightly better quality of anaesthesia for the bitches, although only one study supported this (Metcalfe et al., 2014). With regards to the puppies, no significant differences in mortality was observed. Doebeli et al. (2013) found significantly higher Apgar scores in the alfaxalone group compared to the propofol group in the first 60 minutes of life. Metcalfe et al. (2014) found a greater percentage of puppies in the alfaxalone group were positive for each of the reflexes tested, however this was not statistically significant. Therefore there is some evidence that alfaxalone may also be associated with increased neonatal viability in the first 60 minutes following parturition, however further investigation would help to clarify this.

CONFLICT OF INTEREST
The author declares no conflicts of interest.