While cesarean section is a common surgical procedure, it may be associated with significant mortality in both dams and puppies. Timing is extremely critical for puppy survival for both emergency and elective c-sections. If delivery is delayed by more than 24 hours after the start of the second stage of labor, the loss of all puppies due to placental detachments usually ensues. Emergency c-section should be performed as soon as possible after it is determined that labor is unproductive, before the occurrence of dam exhaustion or distress of the puppies and/or the dam.
Close coordination of the surgeon, anesthetist, and nursing staff is critical. Good preparation of the dam, correct selection of the anesthesia protocol, fast surgical delivery, and adequate neonatal care are the keys to complete success. Ideally, the dam should be totally awake as soon as possible after the procedure to allow for development of the neonatal/maternal bond and maternal adoption of the neonates. This point is critical when considering anesthesia and surgical protocols.
Procedure Pearl: It is important to master each of the surgical steps to reduce the length of the procedure.
Preparation of the Dam
- Shaving the dam prior to induction of anesthesia reduces the time fetuses are exposed to anesthetic agents.
- Maternal oxygenation for 10 to 15 minutes before anesthesia induction (with either a mask or a nasal tube) reduces hypoxia during both intubation and induction/maintenance of anesthesia. It also improves surfactant production in neonates.
- Many dams in distress are dehydrated. Establishing an IV line for fluid will help maintain blood pressure and prevent the effects of blood loss.
- It is the author's experience that, particularly for elective c-sections, an IV injection of a short-acting corticosteroid such as methylprednisolone (Solu-Delta-Cortef; www.pfizerah.com) 2 to 8 hours before surgery stimulates progesterone decrease, prevents shock development, and stimulates surfactant production in neonates, making the success rate significantly higher. The use of methylprednisolone is essential, particularly if the timing of the c-section is approximate. Since timing can be incorrect due to peculiarities of the dog's cycle, particularly if progesterone plasma concentration has not been monitored to evaluate timing, methylprednisolone may be advisable in most cases.
Selection of Anesthesia
The main concerns when choosing the anesthesia protocol are:
- Welfare of dam
- Viability of fetuses
Ideally, the anesthetic drugs should:
- Not cross the placental barrier (eg, glycopyrrolate vs atropine)
- Be short-acting and rapidly or minimally metabolized
- Not depend on liver metabolism or renal excretion, both of which are highly deficient in the canine neonate (eg, propofol vs barbiturates)
- Be reversible by antagonism (if they are not short-acting) and the antagonist should not have any side effects of its own (eg, benzodiazepines vs phenothiazines)
- Provide adequate analgesia for the dam, without affecting the maternal adoption process, maternal behavior, and lactation (eg, opioid injection after delivery of puppies vs the same at induction of anesthesia, a local block vs systemic opioids, or epidural anesthesia vs systemic) The Table summarizes the advantages and disadvantages of the 2 main surgical approaches for performing a uterotomy. For a fast and easy delivery of the puppies and minimal short- and long-term side effects for the bitch, we prefer the technique involving several openings at the level of the great curvature of each uterine horn rather than using only 1 opening at the level of the uterine body. Our technique is described later in Step 5 of the surgical procedure.
Procedure Pearl: Phenothiazines, barbiturates, ketamine, and atropine can all pass through the placenta and can affect the ability of neonates to thrive. Ideally, they should not be used.
The Surgical Procedure: Step By Step Cesarean Section in the Dog