Caesarean sections can evoke stress in even the most experienced small animal veterinarians. They often present as emergencies due to dystocia or elective procedures on economically valuable animals. Anaesthesia for C-sections presents a challenge as the needs of the whelping bitch and her puppies must be balanced, complicating peri-anaesthetic medication choices.
“Heavily pregnant animals have reduced physiological reserves, increasing the complexity of anaesthesia, and that’s before we even take into account the effects of anaesthetics on the foetuses,” says Jurox Technical Services Veterinarian Dr Karen Kerr. “Anaesthetising a patient for C-section requires consideration of maternal and foetal physiology, as well as any concurrent pathology.”
Healthy pregnant animals exhibit a number of physiologic compensations that need to be considered, including increased cardiac output and blood volume to fill the vascular space of developing foetuses. Maintaining the dam’s blood pressure is essential for placental (and foetal) perfusion and should be a priority during anaesthesia.
The oxygen demand of growing foetuses, uterine muscles and mammary tissue increase overall maternal oxygen consumption, while abdominal distension decreases total lung volume. Pre-oxygenation prior to anaesthesia reduces the risk of hypoxia by creating a buffer of oxygen in the lungs that can be drawn on in the case of hypoventilation or apnoea. Decreased oesophageal sphincter tone means regurgitation and aspiration are more likely in pregnant animals, so securing an airway rapidly on induction is essential.
Alfaxan® has been demonstrated to be a suitable anaesthetic induction choice for C-section anaesthesia in the dog. Maternal cardiovascular and respiratory parameters were well maintained, and subsequent puppy vitality assessments were considered better than those where the mother was induced with propofol.
“It is important that newborn animals suckle as soon as possible after birth, making the high-vigour assessments of these puppies especially valuable,” explains Dr Kerr. “The studies also demonstrate that the stability we expect when using Alfaxan extends to use in C-sections, making it an excellent choice for both dam and foetuses and providing the veterinarian with confidence in their protocol.”
In line with their commitment to helping veterinarians practice high-quality anaesthesia, Jurox has compiled a guide to the use of Alfaxan in caesarean sections. The guide includes a summary of the most important physiological and anaesthetic considerations for C-sections, with suggestions of suitable medication choices for each stage of the procedure, epidural anaesthesia protocols and information on resuscitation and care of newborns. There is also a quick reference guide containing practical, concise information for when time is limited.
C-sections may never become completely stress-free, with inherent risk to both mother and offspring, but preparation and consideration of protocols can reduce this and increase staff confidence in achieving the best outcomes for their clients and patients.