Is Your Pup Safer Asleep? Comparing Sedation and Anesthesia for Dogs

Introduction

Sedation and general anesthesia are two common techniques veterinarians use to keep dogs relaxed and pain-free during medical procedures. Sedation involves administering medications to make the dog drowsy and calm but still responsive, while general anesthesia causes the dog to be fully unconscious.

Both sedation and general anesthesia allow vets to safely examine, diagnose and treat dogs. However, they differ significantly in the medications used, level of consciousness, monitoring required and potential risks. Determining which is most appropriate depends primarily on the specific procedure being performed.

1. Definition of Sedation

Sedation refers to administering medication to induce a state where the dog is relaxed, calm, and less anxious but is still awake and able to respond to stimuli (Paws and More Vet, 2022). The medications used for sedation, often combinations of benzodiazepines like midazolam and opioids like butorphanol, result in some depression of the central nervous system. This causes muscle relaxation and moderates the dog’s behavior and reaction to stressors. However, the dog remains conscious and retains normal reflexes like swallowing and blinking. Their level of consciousness is lowered but they are still somewhat alert and awake (Gladesville Veterinary Clinic, 2021).

Since sedation does not induce full unconsciousness, dogs may still feel some pain but their response will be diminished. Sedation does not eliminate pain entirely but provides effective management for mild to moderate pain associated with minor procedures. It reduces anxiety and discomfort but allows procedures to be performed with the dog still awake.

Definition of General Anesthesia

General anesthesia induces a state of total unconsciousness and lack of sensation in order to perform medical procedures on a patient without causing pain or distress. According to the VCA Animal Hospitals, general anesthesia makes the patient “completely unconscious, unaware, and unable to feel pain” (https://vcahospitals.com/know-your-pet/anesthesia-for-dogs). It involves administering intravenous and/or inhalant anesthetic drugs that depress the central nervous system, blocking the brain’s perception of and response to noxious stimuli (AKC.org). General anesthesia causes a reversible loss of consciousness, amnesia, analgesia (pain relief), reflex suppression, and muscle relaxation to ensure the patient remains still and does not respond during surgical procedures.

Procedures Using Sedation

Sedation is commonly used for procedures like dental cleanings and minor surgeries in dogs. Dental cleanings require the dog to remain still for an extended period, which sedation allows. According to Paws & More Vet, injectable sedatives like dexmedetomidine or a combination of acepromazine and butorphanol are often used. They induce a sleepy, relaxed state so the dog can tolerate the dental cleaning.

a vet performing a dental cleaning on a sedated dog.

Sedation is also useful for minor surgeries like laceration repairs or lump removals. It reduces anxiety and discomfort while allowing the dog to maintain normal respiration and protective reflexes. Per Buzzards Bay Vet Associates, injectable sedatives provide safe and effective sedation for minor procedures. The dog remains sleepy but can still be roused if stimulated.

Procedures Requiring General Anesthesia

General anesthesia is required for major surgeries where the dog needs to be fully unconscious and immobilized to ensure safety and precision. This includes orthopedic procedures like total hip replacements, ligament repairs, fracture repairs, and bone realignment surgeries. Keeping the dog completely still is crucial in orthopedic surgeries to enable the surgeon to manipulate and repair the bones and joints. According to the AKC, general anesthesia lasts for 1-2 hours for most orthopedic surgeries to allow enough time for the procedure while keeping the dog unconscious.

a vet monitoring a dog under general anesthesia during surgery.

Other major surgeries requiring general anesthesia include spleen removals, tumor removals, organ transplants, Cesarean sections, gastric bypass, and invasive dental procedures. The level of sedation needed for minor procedures is not enough to perform major invasive surgeries safely. General anesthesia ensures the dog’s muscles are fully relaxed, pain receptors are blocked, and reflexes are eliminated to enable complex surgical techniques.

Monitoring Sedated Dogs

When dogs are sedated, it is crucial to monitor their vital signs closely to ensure their safety and wellbeing. Key parameters to monitor include:

  • Respiratory rate: Respiratory rate may decrease with sedation but should remain >6 breaths/min. Abnormally slow or irregular breathing requires prompt intervention (https://todaysveterinarypractice.com/anesthesiology/anesthetic-monitoring-your-questions-answered/).
  • Heart rate: Bradycardia (slow heart rate) is common with sedation but rates <60 bpm suggest excessive drug effects. Tachycardia (fast heart rate) may signal light anesthesia or pain (http://www.ruralareavet.org/PDF/Anesthesia-Patient_Monitoring.pdf).
  • Reflexes: Important reflexes to check include palpebral (eyelid), corneal, swallowing, and jaw tone. Presence of these reflexes indicates a lighter plane of sedation (https://todaysveterinarypractice.com/anesthesiology/anesthetic-monitoring-your-questions-answered/).

Additionally, monitoring sedation depth, mucous membrane color, jaw relaxation, and response to stimuli provides key information. Close monitoring allows adjustment of sedative doses to maintain desired effects.

Monitoring General Anesthesia

using a pulse oximeter to monitor a dog's oxygen level.

Monitoring general anesthesia in dogs is crucial as it allows veterinarians to detect and address any concerning changes in the patient’s condition during the procedure. The key parameters that are monitored include:

Respiratory Rate: This measures the rate of breathing and detects any abnormalities like apnea or hyperventilation. Respiratory rate is tracked continuously via devices like capnography, which monitor exhaled carbon dioxide.[https://www.dispomed.com/veterinary-anesthesia-monitoring/]

Oxygen Levels: Pulse oximetry uses a sensor clipped to the tongue, ear or paw to measure hemoglobin oxygen saturation. Normal levels are 95-100%, with anything under 90% warranting intervention.[https://todaysveterinarypractice.com/anesthesiology/anesthetic-monitoring-devices-to-use-what-the-results-mean/]

Heart Rate: Electrocardiography (ECG) monitors the electrical activity of the heart to detect abnormal rhythms. Typical heart rate is 60-160 bpm in an anesthetized dog.[https://todaysveterinarypractice.com/anesthesiology/anesthetic-monitoring-devices-to-use-what-the-results-mean/] Blood pressure is also tracked as it relates to cardiac output.

Veterinarians continuously monitor these parameters during general anesthesia and quickly intervene if any dangerous changes occur that could compromise the patient’s wellbeing.

Risks of Sedation

Sedation in dogs does carry some risks, although they are generally less severe than with full anesthesia. The main risks of sedation are:

Respiratory depression – Sedative drugs can cause slowed or ineffective breathing. Mild sedatives may just cause slight respiratory depression, but stronger drugs can severely inhibit the drive to breathe (Source: RVAC Study). Monitoring breathing rate and oxygen levels is important.

Vomiting – Some sedative drugs can cause nausea and vomiting. This is generally mild, but can lead to aspiration pneumonia if vomit enters the lungs. Using antiemetic drugs can help prevent vomiting.

Risks of General Anesthesia

General anesthesia carries more risks than sedation. Some of the most concerning risks of general anesthesia in dogs include:

a vet checking an anesthetized dog's blood pressure.

Low blood pressure – Also known as hypotension, low blood pressure during general anesthesia can deprive the dog’s organs and tissues of oxygen (VCA Animal Hospitals). This happens because anesthesia dilates blood vessels while also depressing cardiac function. Low blood pressure may require medical intervention to maintain adequate perfusion.

Prolonged unconsciousness – General anesthesia depresses the central nervous system more profoundly than sedation. This makes it harder for the dog to emerge from unconsciousness after the procedure is complete (AKC). Prolonged unconsciousness may require medical intervention to stimulate and support the dog’s breathing and cardiovascular function during recovery.

Conclusion

Both sedation and general anesthesia carry risks for dogs undergoing procedures. However, sedation is generally safer and has fewer risks than general anesthesia.

Sedation produces a state where the dog is relaxed but can still swallow and breathe on its own. It is typically used for minor procedures like x-rays, dental cleanings, stitching lacerations, and ultrasound imaging. The risks of sedation include lowered blood pressure and slowed heart/breathing rates. With proper monitoring, these side effects can be managed.

General anesthesia causes total unconsciousness and loss of pain sensation. It is required for surgeries and major procedures where the dog must be completely still and unaware. There are greater risks with general anesthesia including dangerous drops in blood pressure and oxygen levels. Dogs can experience heart or breathing failure. Careful monitoring by trained staff is essential.

In conclusion, for minor veterinary procedures, sedation presents fewer risks and is safer for most dogs. However, general anesthesia remains necessary for surgeries and complex procedures despite greater risks. The choice depends on weighing the benefits vs potential dangers based on the dog’s health status and the procedure being performed. With proper precautions, both can be administered safely.

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