When to Proceed with the C-Section
By Richard Wheeler, DVM
Breeding dogs is not cheap monetarily, emotionally, or with the amount of time invested. Precious lives are involved. Please breed responsibly.
As a breeder you may have been or will be faced with the decision to proceed to C-section for management of a whelping bitch. For those of you who would like me to give you the definitive answer as to when to proceed to c-section, proper anesthetic protocol, and best surgical approach; I am sorry to inform you that there are too many variables and too many options for one simple answer.
Veterinarians experienced in dystocia management and cesarean delivery are perhaps the single most important factor for a successful outcome. Expedient delivery increases the survival of pups., shortening the duration of surgery and minimizing the potential for complications.
Fetal oxygenation is the foremost liability during the operation. All anesthetic and surgical decisions pivot around fetal oxygen delivery. Without oxygen, puppies suffocate or become severely debilitated and expire soon after delivery.
Fetal oxygenation can be affected in 3 ways; first, decreased maternal blood flow to the uterus. Uterine blood flow is primarily affected by blood pressure, either being too high or too low. Low blood pressure routinely occurs with the use of any anesthetic. To minimize this effect, maintain the lowest level of anesthesia possible and avoid sedatives such as Acepromazine. Fluid administration before induction of anesthesia and during the surgery will also help maintain normal blood pressures. Finally, avoid hypothermia; low body temperature contributes to low blood pressure.
Anxiety, stress, and pain result in high blood pressure, which also decreases perfusion of the uterus. Sedation of animals can minimize this effect but should be done judiciously so as not to adversely affect the fetuses. Avoid use of Xylazine (which increases blood pressure), and Acepromazine (as previously mentioned). Opioids (morphine derivatives) are the sedative of choice. Further, hyperventilation of the dam increases blood pressure and should be
Second, fetal oxygenation can be affected by decrease concentration of oxygen in the dams blood. This can occur if the dam stops breathing or is unable to take deep breaths. Pre-oxygenating the bitch for 3-5 minutes with 100% oxygen before she is anesthetized maximizes the oxygen concentration in her blood. Positioning the bitch at an angle on her right side (as opposed to directly on her back) will facilitate blood flow to her heart and lungs for re-oxygenation. And administering a deep breath occasionally to the bitch with the ventilator will also improve oxygenation during surgery.
Because it is impossible to directly measure fetal oxygen status, monitoring the blood pressure of the dam and oxygen saturation of her blood provides appropriate estimations of fetal oxygen perfusion. Many veterinary clinics are capable of evaluating these vital signs with capnographs, oximeters, and blood pressure monitoring equipment.
Third, fetal oxygenation is affected by the fetuses ability to breathe at delivery. Use of Xylazine and/or Ketamine have been associated with decrease puppy survival, presumably from residual affects on the puppies delaying spontaneous respiration. Stimulation of fetal breathing is best accomplished using gentle, yet vigorous stimulation in towel drying. Clear the airway using an infant suction bulb or a dry cotton-tipped swab, as opposed to swinging the puppy; which may result in neck or head trauma or regurgitation and aspiration of stomach contents. Warming the puppy with a warm hair dryer, incubator, or radiant heat source will also facilitate respiration. If the puppies do not begin breathing within 30 seconds, or the heart rate begins to decrease, provide supplemental oxygen, and attempt positive pressure ventilation with a face mask or intubation. Stimulation of the acupuncture point at the juncture between the base of the nose and upper lip using a 25 gauge needle with rapid, pecking motions may also stimulate respiration. If the heart rate continues to drop and breathing does not ensue, administration of Epinephrine is warranted. Routine use of Doxipram is not advocated: it has not been proven to be efficacious, and may cause cardiac infarction.
Recent studies demonstrate that no single anesthetic drug is superior to another in affecting survival of puppies; with the exception of Xylazine and Ketamine mentioned above. My preferred anesthetic protocol is Propofol induction with gas anesthesia using either Isoflurane or Sevoflurane.
There is no single surgical approach which has been proven more effective then another. The important factor is that the surgeon is competent at the approach she/he elects to use. If hysterectomy (spaying) is elected or required (because of uterine rupture or uterine artery rupture) at the time of c-section, fastidious attention must be paid to ligation of engorged uterine vessels. There is no consequence to the bitch or the puppies if spaying is accomplished at the time of delivery. Anecdotal reports of decreased lactation have been reported; but have no physiologic substance. If the owner elects to delay spaying the bitch, my recommendation is to proceed with the subsequent surgery after weaning the pups and before the next heat ensues.
Post-operatively, greater puppy survival is achieved when the bitch is alert and attentive to the puppies. Maternal stimulation of urination, defecation, nursing, activity and body heat are critical. To this end, decreased exposure to sedatives and anesthetics by lowering doses and decreasing surgery time are most beneficial. Second, use of post-operative analgesics provide pain relief so the bitch will allow the puppies to nurse and be attentive to them. Intra-operative administration of opioids, or post operative use of non-steroidal anti-inflammatories are most effective. Local infusion of a line block over the incision site may provide temporary relief.
Richard Wheeler, DVM, Diplomate ACT (Board Certified, Reproduction)
Poudre River Veterinary Clinic
Affiliate: CSU Veterinary Teaching Hospital
Fort Collins, CO