Going Under

Even when they are routine, surgical procedures in the giant-breed dog can be stressful for the veterinarian and owner alike. While the surgery itself is often the center of the discussion, attention to appropriate anesthesia can be equally as important for a successful outcome.

 

Any anesthetic event involves a three-tiered approach: premedication, induction and maintenance. There can be many simple modifications within that protocol to increase the safety and success of the procedure for Molosser breeds. 

 

In the first step, premedication, drugs are given to sedate the animal. Typically this includes a tranquilizer and/or pain medication. The important points concerning this area of anesthesia include:

 

Basic blood work will help verify that the dog’s liver and kidneys are healthy enough to appropriately metabolize any drugs. Blood work can also give hints that the dog may have an underlying illness and thus may necessitate additional supportive measures during surgery. Some conditions may even require surgery to be postponed.

 

The gold standard for pre-anesthetic bloodwork includes the complete blood count (CBC) and the blood chemistry (CHEM). For the young, stable and healthy dog, the packed cell volume (PCV) total protein (TP) and blood urea nitrogen (BUN) are often considered the bare minimum for pre-anesthetic bloodwork.

 

Many Molosser health organizations also recommend testing for bleeding disorders such as von Willebrands disease (vWD). A clotting panel is a great additional test to include prior to surgery to help avoid some of these dangerous bleeding complications.

 

It is common knowledge among many veterinary anesthesiologists that giant-breed dogs require lower dosages per body weight than medium and large-breed dogs. Most veterinarians are familiar with this, but it never hurts to remind them before your dog undergoes a procedure.

 

As far as specific drugs go, acepromazine, or ace, usually gets the most press. Ace is a drug commonly used during premedication for sedation. Giant breeds are known to be more sensitive to the drug and are thus at higher risk for overdose. If given in excess, ace can cause dangerous drops in blood pressure and can prolong sedation. Ace can easily be excluded from the premedication drug mixture, especially if your dog is calm and well behaved. It is worthwhile to discuss this option with your veterinarian before your dog undergoes an anesthetic procedure. 

 

After the premedication drugs are administered, the dog should remain visible so that adverse reactions can be dealt with quickly. It is a good idea to check to make sure your veterinarian has a crash cart and an emergency resuscitation policy, so if an adverse reaction or emergency occurs during surgery and anesthesia, the veterinarian and staff can be immediately prepared.

 

Proper pain control prior to the procedure can decrease the amount of drugs required during the surgery, the amount of pain medication required after the surgery and can help prevent many post-operative complications. Please note that pain control, or analgesia, is a highly debated area of veterinary medicine.

 

The second step of the anesthetic procedure is induction, where a variety of drugs can be used to begin the state of anesthesia. These drugs can be the only ones used, especially if the procedure is short. The specific drugs are often of less importance; what is important is that the veterinarian is familiar with the drug and prepared to deal with all of the possible side effects. The drug xylazine, Rompun®, often gets a lot of press. Xylazine has fallen out of favor with most modern small-animal anesthesiologists as it can cause more adverse reactions than the other induction drugs. The important areas concerning induction of anesthesia include:

 

In this day and age of piecemeal surgeries, be sure you clarify beforehand if an IV catheter will be used. An IV catheter increases the chance that appropriate administration of the drugs will occur during induction. It also provides quick access so that rescue medications can be given if things go wrong and gives a route for supportive fluids. 

 

In many states, a licensed veterinary technician or a veterinarian must administer drugs. Experienced personnel are usually more capable of identifying abnormal reactions and quickly dealing with an emergency.  It is never wrong to ask who will be administering drugs to your dog.

 

The third step is maintenance, during which injectable drugs are given at a continuous rate, or the dog is intubated and gas anesthesia is used. The important areas concerning maintenance include:

 

Because giant-breed dogs are inherently at higher risk during anesthesia, there should always be someone watching your dog in addition to the surgeon. Whether it is manually or via electrical monitoring, ideal monitoring includes: heart rate, rhythm, blood pressure, core body temperature and respiratory rate.

 

No matter the procedure, supportive care is critical to the success of the surgery and to a smooth recovery from anesthesia. Appropriate supportive care for the giant-breed dog includes: padding, IV fluids, temperature regulation and extra vigilance. 

 

The heavy body weight of the Molossers can cause pressure injuries to muscles and nerves during the procedure. Extra padding should always be used to protect the spine, hips, neck and head. Finding a veterinary hospital that uses a lift table can also help prevent the muscle strains that can occur if giant dogs are physically moved. If a lift table is not available, two to three people should always be used to move a giant-breed dog, giving extra support to the head, neck and limbs.

 

Except in short (less then 10 minute), simple procedures, IV fluids should be used throughout anesthesia. They are absolutely critical with procedures where large volumes of blood may be lost or when the abdomen is opened. Low blood pressure, or hypotension, is a common side effect of many anesthetic drugs, and IV fluids provide an easy means of counteracting this effect. A dog with IV fluids usually stays well hydrated, and this can help flush the anesthetic drugs out of the system more quickly after the procedure.

 

Some type of temperature regulation is also important during anesthesia, as a giant-breed dog’s temperature can drop dramatically, especially during long procedures. Low core body temperature increases the rate of infection and prolongs the duration of recovery.

 

Lastly, anesthesia ends when the dog is fully awake and recovered; proper monitoring includes watching the dog until he is fully awake – not just until the end of the procedure.  Dogs commonly can thrash and flail as they recover; having extra padding and someone there to monitor can help minimize injuries during this period. Molossers with short muzzles should be left intubated for as long as possible to encourage appropriate postoperative oxygenation.

 

Please note that while ideal, these measures are not always possible with many Molossers. While recovering, many dogs are disoriented and scared, and this can make them dangerous. With giant guardian breeds, this effect is often amplified. Being in a quiet, dark padded area with someone calmly monitoring is the best place for recovery.

 

The risks of a surgical procedure do not end on the day of the surgery. In addition to the usual complications – infection, self-trauma, dehiscence (where the staples or suture fails and the wound opens) – giant-breed dogs are at greater risk for bloat. In addition to fasting before a procedure, keeping a Molosser off food until the day after anesthesia can reduce the risk of bloat. Extra vigilance for a couple days after any anesthetic procedure, no matter how small, is always recommended. 

 

Anesthesia will always be a nerve-wracking experience for the Molosser owner. These simple tips will hopefully allow a greater degree involvement during the anesthetic procedure to minimize some of the anesthetic risks commonly found in the Molosser. 

 

Dr. White is a breeder-veterinarian who breeds and shows Neapolitan Mastiffs. She owns a mixed-animal house-call practice in Oregon. She enjoys working with breeders and performance-dog enthusiasts and is a founding member of the Mastino Health Foundation.