Veterinarian wearing gloves and holding the neck of a dog

Pet Anesthesia and Patient Monitoring

At our hospital, each patient has one or more technicians dedicated full time to your pet’s anesthetic monitoring under the care of the veterinarian. These technicians are with your pet from induction (initiation of anesthesia) right through to their full recovery.


Westbridge Veterinary Hospital staff member wearing a mask and touching a knob on a monitor

We take the safety of your pet under anesthesia very seriously. Each patient undergoing anesthesia has a specific drug protocol tailored individually based on their species, age, breed, and the procedure in which they are undergoing.

Anesthetic maintenance and monitoring are crucial for a successful surgical procedure. As such, in addition to a technician dedicated to hands-on monitoring including pulse quality (to identify blood pressure and arrythmias), mucous membrane colour and capillary refill time, and other parameters such as jaw tone and the presence of a palpebral reflex (to assess anesthetic depth), the anesthetic patient is hooked up to our monitors which are at all times monitoring over eight different parameters.

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Every patient at Westbridge Veterinary Hospital undergoing a procedure requiring anesthesia is placed on intravenous fluids. This is important in maintaining blood pressures, the importance of which is outlined below. In addition, it provides intravenous access which is crucial to the administration of life saving drugs in the event of an anesthetic emergency.

A dog being placed on intravenous fluids and undergoing a procedure requiring anesthesia

Blood Pressure Monitoring
Blood pressure monitoring is essential to a patient under anesthesia. Blood pressure is the driving force for blood flow (perfusion) through capillaries that supply oxygen to organs and tissue beds of the body. Low blood pressure results in decreased oxygen delivery, resulting in the death of important cells and organ damage, most sensitively the kidney and brain. Because lowered blood pressure is a common side effect of many anesthetic drugs, monitoring these values under anesthesia is crucial. At Westbridge, a state-of-the-art non-invasive blood pressure monitor is hooked up to your pet at all times, using the two leaders in non-invasive blood pressure monitoring. Changes in blood pressure can be determined quickly and accurately, allowing for appropriate interventions, increasing the safety for your pet.

Capnography – CO2 (carbon dioxide) Monitoring
CO2 monitoring is extremely valuable to a patient under anesthesia. It is the most accurate tool conventionally available to assess the respiratory system in a patient under anesthesia. Inadequate ventilation (or ‘breathing’) can result in increased CO2 levels, which can cause arrythmias, altered blood flow to the brain, and potentially death. This is particularly important to patients with airway disease (such as asthma), or to overweight animals. CO2 is also the most accurate tool we have to assess cardiac output, or the strength and effectiveness of the hearts contractions.

Anesthesia always results in a dramatic reduction in body temperature, particularly in long procedures. Decreased body temperatures is associated with prolonged recovery and increase in post-surgical infections. Every anesthesia patient is monitored through an esophageal thermometer which gives an accurate representation of core body temperatures. Every anesthetic patient is provided with a Bair Hugger, a forced-air device that safely fills a blanket around the patient with warm air at 39 degrees to maintain body temperatures extremely effectively.

ECG / EKG / Electrocardiogram
An electrocardiogram detects and amplifies tiny electrical changes on the skin that are caused when the heart muscle “depolarizes” during each heart beat. This helps to detect arrhythmias which can be caused by anesthesia or heart disease, and when present can be potentially fatal if left untreated.

Heart and Respiratory (Breathing) Rate
Heart rate and respiratory rate are measure constantly though an anesthetic procedure. These values are useful for many reasons, including assessing anesthetic depth, body temperature, drug reactions, etc. These are monitored both by our anesthetic monitor, as well as by the technician by visualizing and characterizing each breath, as well as through a stethoscope.

SPO2 – Oxygen Saturation
SPO2 is a measure of the amount of oxygen that is dissolved in the blood stream, carried by red blood cells. This ensures that a patient is receiving adequate amounts of oxygen. Lowered O2 can be a result of inadequate breathing, lung disease, excessive intravenous fluids, bleeding, and much more.

The Human Touch
Arguably as important as any monitored parameter is the presence of a trained technician managing your pets anesthesia at all times, under the supervision of the veterinarian. Our technicians undergo year round training and continuing education to further their anesthesia skills, and to stay up to date with modern anesthesia. Their presence is imperative to the safety of your pet, and to verify the accuracy of the various monitors. Changes in the parameters monitored can be assessed immediately, allowing various interventions necessary, such as adjusting the depth of anesthesia, or to deliver necessary medications.

Screenshot of monitor screen with lines

Anesthetic Machine
Our anesthetic machines are designed specifically for the use in small animal anesthesia. Our machines are tested every morning by our technicians prior to surgery to ensure their function and accuracy. Oxygen flow rates, re-breathing bag sizes, and circuit type are carefully modified for each patient.

Coaxial anesthetic tubing on anesthetic machines (below) helps retain body heat while the pet is under anesthetic.


Dog thinking about ticks and fleas

Year-round protection means more peace of mind!

“Tick season” used to mean spring/summer/fall, with a break over the winter – the colder weather meant that we could take a break from worrying about these pesky bugs and the diseases they can transmit. But in the last few years, we’ve seen a change creeping up on us, with the weather staying warm later into the season, and spring arriving earlier each year – and the bugs are loving it! You may have already heard us talking about how any day that the temperature is above the freezing point, ticks are potentially active. This past year, we had days above 0°C in all 12 months! Ticks aren’t killed by the cold, they simply go dormant, waiting until it’s warm enough to come back out – so last year, even January and February had days warm enough for ticks to be active! This means that we are now recommending that all dogs (and cats that go outdoors) take advantage of year-round flea and tick protection. There are several options, our first choice being an all-in-one that protects against fleas, ticks, and heartworm, as well as providing regular deworming against roundworms. One pill, once a month – what could be simpler? If your pet is already on a monthly preventative, all you need to do is pick up a refill and continue throughout the winter months. If your pet hasn’t yet started on comprehensive parasite prevention, we’re happy to answer any questions you may have and set you up with the best option for your pet. What does this mean for testing? The 4DX test that we recommend most commonly screens for heartworm disease, Lyme, Ehrlichia, and Anaplasma. Heartworm is transmitted by mosquitoes (so every dog in Ontario is potentially at risk – at Westbridge we treat a few cases every year!), and the others are all transmitted via tick bites. We have seen an increase in Lyme-positive dogs in the last few years, one of the reasons we are recommending some of these changes. For better early detection and the safety of your pet, we are recommending annual 4DX testing for all dogs. This simple blood test can be done at any time, although the optimal time is in the spring. Catching disease early is key to successful treatment – and no matter how careful you are with preventative medications, there is always some risk of infection. As always, our veterinarians and registered veterinary technicians are available to answer any questions you may have about the best options for your pet. Email us at info@westbridgevet.com, or call us at 905-285-0002

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Last updated: December 17, 2020

Dear Clients,

With recent changes to restrictions on businesses, we are pleased to advise that effective May 19, 2020 some restrictions on veterinary practices have been lifted. Based on these changes, below are some important updates to our operating policies.


This includes vaccines, wellness exams, blood work, heartworm testing, spays and neuters, dental services, and more!



We are OPEN with the following hours:

- Monday to Friday: 10:00 am - 6:00 pm
- Saturday: 8:00 am - 1:00 pm
- Sunday: CLOSED


Have you welcomed a new furry family member to your home? We’d love to meet them! Visit our Must Know New Pet Owner Information page for useful resources and helpful recommendations for new pet owners.

Thank you for your patience and understanding and we look forward to seeing you and your furry family members again!

Your dedicated team at Westbridge Veterinary Hospital