How long does it take for the cat to wake up from the anesthesia?

Author: John Stephens
Date Of Creation: 25 January 2021
Update Date: 19 May 2024
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What to expect when your cat is recovering from anesthesia
Video: What to expect when your cat is recovering from anesthesia

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There are many reasons why a cat should be sedated or anesthetized, from aggression or fear in a veterinarian visit or for minor surgical procedures or large scale operations. the anesthesia, especially the general one, it's very safe, contrary to what many tutors think, as with current knowledge of medications, the percentage of death from anesthesia is less than 0.5%.

But how long does it take for the cat to wake up from the anesthesia? What is the cat's estimated recovery time after surgery? In this article by PeritoAnimal, we tell you everything about anesthesia and sedation in cats, what to do before, its phases, effects, medications and recovery. Good reading.


Difference between sedative and anesthesia

Many people confuse sedation with anesthesia, but the truth is, they are two very different processes. THE sedation it consists of a state of central nervous system depression in which animals fall asleep with little or no response to external stimuli. On the other hand, the anesthesia, which can be local or general, the general one causing loss of generalized sensation by hypnosis, muscle relaxation and analgesia.

However, before submitting your cat to surgery, your veterinarian will talk to you about the pre-anesthetic exam. This is very important to assess your feline companion's health status and to plan the best anesthetic protocol for your individual case. This consists of:

  • Complete medical history (existing diseases and medications)
  • Physical examination (vital signs, mucous membranes, capillary refill time and body condition)
  • Blood analysis and biochemistry
  • Urine analysis
  • Electrocardiogram to assess the state of the heart
  • In some cases, also radiographs or ultrasound

How long does sedation last for a cat?

A cat's sedation time depends on the type of procedure performed, which varies according to the duration and intensity of the procedure and the individual feline variability. To sedate a cat, combinations of sedatives, tranquilizers or analgesics can be used, such as the following:


Phenothiazines (acepromazine)

How long does sedation last for a cat with phenothiazines? About 4 hours. This is a sedative that takes a maximum of 20 minutes to act, but with an effect of 4 hours on average. the animal must be oxygenated if used as a sedative due to the cardiovascular depression it produces. It is characterized by:

  • Antiemetic (does not cause vomiting)
  • deep sedation
  • It has no antagonist, so the cat will wake up when the drug is metabolized
  • Bradycardia (low heart rate)
  • Hypotension (low blood pressure) of up to 6 hours in duration
  • Do not produce analgesia
  • moderate muscle relaxation

Alpha-2 agonists (xylazine, medetomidine and dexmedetomidine)

How long does it last to sedate a cat with alpha-2 agonists? They are good sedatives that take a maximum of 15 minutes to act and have a shorter duration of sedation, about 2 hours. They have an antagonist (atipamezole), so if used, they will wake up in a short time without having to wait the necessary time until the sedative effect wears off. It must be oxygenated due to the cardiovascular effects they produce:


  • Good muscle relaxation.
  • Moderate analgesia.
  • Emetic (induces vomiting).
  • Bradycardia.
  • Hypotension.
  • Hypothermia (drop in body temperature).
  • Diuresis (more urine production).

Benzodiazepines (diazepam and midazolam)

How long does sedation last for a cat with benzodiazepines? From 30 minutes to 2 hours. Benzodiazepines are relaxants that take a maximum of 15 minutes that have an antagonist (flumacenil) and produce the following effects:

  • powerful muscle relaxation
  • Has no effect on the cardiovascular system
  • do not sedate
  • Do not produce analgesia

Opioids (butorphanol, morphine, methadone, fentanyl and pethidine)

How long does the sedation of a cat with opioids last? About two hours. Opioids are good analgesics used on many occasions with sedatives to contribute to sedation or to prepare the cat for anesthesia. They tend to depress the cardiorespiratory center a lot and some, like morphine, are emetic. In the past, it was believed that opioids, such as morphine, were contraindicated in cats because of their stimulant effects. Nowadays can be used without problems, but maintaining the dosage, route, schedule and combination of medications, as problems arise if they are overdosed, causing dysphoria, delirium, motor excitability and seizures.

On the other hand, while butorphanol produces less analgesia and is used in sedation or for premedication before general anesthesia, methadone and fentanyl are the most used in this species for control the pain during surgery due to its greater analgesic potency. They have an antagonist to reverse their effects called naloxone.

Therefore, the duration of sedation will depend on the cat's own metabolism and state. The average is about 2 hours if not reverse sedation with the antagonist. By combining two or more drugs from different classes, it allows to increase the desired pharmacological effects and, thus, reduce doses and Side effects. For example, the combination of butorphanol with midazolam and dexmedetomidine is usually very effective to sedate a nervous, painful, stressed or aggressive cat in consultation, and having an antagonist reverses the effects, being able to go home awake or slightly drowsy.

How long does it take for the cat to wake up from the anesthesia?

a cat takes a long time an hour, less or even several hours to wake up from the anesthesia. This depends on the procedure performed and the cat's health conditions. Therefore, it is important to note that anesthetic procedures consist of four phases:

Phase 1: premedication

Your main objective is to create a "anesthetic mattress" to decrease the dose of subsequent anesthetics, reducing the side effects of dependent doses, reducing stress, fear and pain in the cat. This is done by administering different combinations of the sedatives, muscle relaxants, and pain relievers that we discussed in the previous section.

Phase 2: anesthetic induction

By administering an injectable inducing anesthetic, such as alfaxalone, ketamine or propofol to make the cat lose its reflexes and, thus, allow intubation (insertion of a tube in the feline trachea for the introduction of inhaled anesthetic) to continue the anesthetic process.

These phases usually last about 20-30 minutes in total until the drugs take effect and allow for the next step.

Phase 3: maintenance

consists of the continuous administration of an anesthetic agent, either in the form of:

  • Inhalation: (such as isoflurane) along with analgesia (opioids such as fentanyl, methadone or morphine) and/or non-steroidal anti-inflammatory drugs such as meloxicam which will improve postoperative pain and inflammation. The latter can also be administered at the end of anesthesia together with the antibiotic to prevent possible infections.
  • intravenous: Propofol and alfaxalone in continuous infusion or repeated bolus with a potent opioid such as fentanyl or methadone. Its use is not recommended for more than an hour or two in cats to avoid slow recoveries, especially with propofol.
  • Intramuscular: ketamine and opioid for short 30-minute surgeries. If more time is needed, a second dose of intramuscular ketamine can be given, but not more than 50% of the initial dose.

The duration of this phase is variable and it will depend on the type of surgery what your cat will be subjected to. If it's a cleaning, around one hour; a castration, a little more, like taking biopsies; if you operate on a foreign body, such as hairballs, it may take a little longer, while if it's trauma operations, they may last several hours. It also depends on the surgeon's skill and possible intraoperative complications.

Phase 4: recovery

After completion of anesthesia, resuscitation begins, which must be quick, stress-free and pain-free if the procedure, combinations and doses of medications used are respected. You will need to monitor your constants, your condition, your temperature and, later, possible complications such as fever and vomiting, which may indicate an infection. Generally, a healthy, well-fed, vaccinated, and dewormed adult cat recovers from anesthesia 2 days after the intervention and its sequelae 10 days later.

Thus, the duration of anesthesia varies according to the duration of the surgery, the animal's state and metabolism, the surgeon's skills, complications, medications used and resuscitation time. So, in relation to the question about how long it takes the cat to wake up from the anesthesia, the answer is that some anesthesia lasts an hour or less, others can last several hours. But don't worry, with a correct anesthetic protocol, analgesia, control of vital constants and temperature by the anesthesiologist, your cat will be safe and without feeling any pain or stress, regardless of the duration of anesthesia.

My cat is not recovering from anesthesia

The time it takes the animal to recover from the anesthesia will depend on the amount administered, the type of anesthesia used and also the cat itself. Even if your little cat has fasted before surgery, it may still have some bile or food leftovers in its stomach or feel nauseous.

Don't worry, it's normal if alpha-2 sedatives or some opioids are used. It is also normal for a cat after waking to go sideways disoriented or meow for no reason, take a few hours to eat, or urinate heavily that day to eliminate the extra fluid administered with fluids during anesthesia. During the postoperative recovery of a neutered cat, for example, it is necessary for him to stay in a hot, dark and silent place.

sometimes cats can take a long time to wake up. Keep in mind that cats are very different from dogs in many ways. In anesthesia, they would be no less. In particular, the metabolism of medications in cats is much slower than in dogs, so they may take longer to wake up. Your cat may take longer to recover from anesthesia for the following reasons:

Enzyme Deficiencies

One of the most important ways of metabolizing drugs for their subsequent elimination is their conjugation with glucuronic acid. However, cats have a glucuronyltransferase enzyme deficiency, who is responsible for this. Because of this, the metabolization of drugs that use this pathway becomes much slower when having to use an alternative: sulfoconjugation.

The origin of this deficit is found in the eating habits of felines. Being strict carnivores, have not evolved to develop systems to metabolize plant phytoalexin. Therefore, in cats certain drugs (ibuprofen, aspirin, paracetamol and morphine) should be avoided or used in much lower doses than in dogs, which do not have this problem.

Propofol as an anesthetic

The use of propofol in maintenance as an anesthetic for over an hour can prolong recovery time in cats. In addition, repeated propofol anesthesia in felines can produce oxidative damage and the production of Heinz bodies (inclusions that form in the periphery of red blood cells by the destruction of hemoglobin).

Drug overdose

Cats tend to weigh little, especially if they are small, so they can more easily overdose with the consequent lengthening of the recovery process, taking much longer to metabolize, so that they stop performing their action. In these cases, only antagonist drugs would be indicated, but taking into account that awakening can be sudden and dysphoric. In fact, the tendency is to try to wake up more progressively and slowly, with the help, if necessary, of relaxants such as benzodiazepines.

Hypothermia

Hypothermia in cats or a drop in body temperature is common due to their small size and weight. The more the temperature drops, the more difficult it is to metabolize drugs, due to reduced enzymatic function, prolonging recovery and awakening from anesthesia. This condition must be prevented by applying insulating materials over the animal and covering it with blankets or using heated surgical tables, applying heated fluids, as well as maintaining the operating room temperature around 21-24 ºC.

Now that you know how long it takes for the cat to wake up from the anesthesia, this video on castration in cats might interest you:

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