Home > Related Diseases > Anaesthesia
Overview
- Many cats will need anaesthesia at some point in their lives.
- Anaesthesia always carries a small risk, and this risk can be higher in a CKD cat.
- This page explains more about the precautions you can take to minimise the risks.
Introduction
Sometimes a CKD cat needs to have a general anaesthetic. The most usual reason in a CKD cat is dental surgery, but cats sometimes need anaesthesia for other reasons, perhaps to have a growth removed or to have kidney stones treated.
I know you don’t want your cat to undergo general anaesthesia. The mere thought of it terrifies me, and I’m a gibbering wreck whenever one of my cats needs it. There are always risks associated with anaesthesia, but if your cat is in pain (and believe me, dental pain is horrible), or if s/he won’t survive much longer without surgery, then you will have to decide whether to go ahead.
Long Beach.Animal Hospital has detailed information on anaesthesia written for laypeople.
Pet Place gives an overview of anaesthesia.
Risks of Anaesthesia
The risks of anaesthesia are varied, but breathing and heart rate may be affected, and aspiration may occur if the airway is not protected.
Low blood pressure (hypotension) can be caused by anaesthesia. AAFP feline anesthesia guidelines (2018) Robertson SA, Gogolski SM, Pascoe P, Shafford HL, Sager J & Griffenhagen GM Journal of Feline Medicine and Surgery 20(7) pp602-634 say “hypotension is a common anesthetic complication, even in healthy cats undergoing short procedures.”
Hypotension is a particular concern for CKD cats because it may damage the kidneys and therefore increase the risk of CKD developing or worsening. Risk factors associated with the development of chronic kidney disease in cats evaluated at primary care veterinary hospitals (2014) Greene JP, Lefebvre SL, Wang M, Yang M, Lund EM & Polzin DJ Journal of the American Veterinary Medical Association 244 pp320–327 found that “Risk factors for CKD in cats included … prior periodontal disease or cystitis, anesthesia or documented dehydration in the preceding year.”
What is considered hypotension? AAHA Anesthesia and Monitoring Guidelines for Dogs and Cats (2020) Grubb T, Sager J, Gaynor JS, Montgomery E, Parker JA, Shafford H & Tearney C Journal of the American Animal Hospital Association 56(2) pp59-82 say “hypotension is a common complication during anesthesia and is defined as BP values of systolic ,80–90 mm Hg, mean ,60–70 mm Hg, and diastolic ,40 mm Hg.”
Fortunately, many of the risks can be managed, which reduces the chances of problems developing. The risk of death: the confidential enquiry into perioperative small animal fatalities (2008) Brodbelt DC, Blissitt KJ, Hammond RA, Neath PJ, Young LE, Pfeiffer DU & Wood JL Veterinary Anaesthesia & Analgesia 35(5) pp365-73 reports on the anaesthesia of 79,178 cats and found the risk of death was 0.24%, rising to 1.4% in sick cats. The study states that “Greater patient care in the postoperative period could reduce fatalities.”
Preparing for Surgery
According to AAHA Anesthesia and Monitoring Guidelines for Dogs and Cats (2020) Grubb T, Sager J, Gaynor JS, Montgomery E, Parker JA, Shafford H & Tearney C Journal of the American Animal Hospital Association 56(2) pp59-82, ““anesthesia” is not limited to the period when the patient is unconscious but is a continuum of care that begins before the patient leaves home and ends when the patient is returned home with appropriate physiologic function and absent or minimal pain levels.”
The first thing to do is to find a vet you trust to perform the surgery. As Robert Smith MD put it, “There are no safe anesthetic agents, there are no safe anesthetic procedures. There are only safe anesthetists.” (Smith’s Anesthesia for Infants and Children (1959) Mosby).
You also need to decide whether to use a specialist. Most vets can perform a variety of surgical procedures, but for certain types of surgery, such as kidney stone treatment such as SUBs or stents, you will need a specialist. You may also wish to use a dental specialist if your cat is undergoing dental surgery (see Dental Problems for more information).
You should always have a physical exam and bloodwork performed and blood pressure checked before surgery, so any problems can be addressed. If your cat has heart issues, you may also wish to see a veterinary cardiologist prior to surgery.
If your cat is on blood pressure medication such as amlodipine (Norvasc) or benazepril (Fortekor), ask your vet if you need to stop the medication before the surgery (since anaesthetics may reduce blood pressure). AAHA Anesthesia and Monitoring Guidelines for Dogs and Cats (2020) Grubb T, Sager J, Gaynor JS, Montgomery E, Parker JA, Shafford H & Tearney C Journal of the American Animal Hospital Association 56(2) pp59-82 advises stopping benazepril and has a list of which medications can normally be given and which not.
It is very important to fast your cat before anaesthesia. This will usually be done for several hours before surgery, often overnight, but a shorter period may be possible in some cases, so be guided by your vet. Your cat may be allowed to drink water until a couple of hours before surgery, which can be helpful for a CKD cat, but your vet will decide what is the best approach for your cat.
You may be pushing your luck a little with this, but it may be worth asking your vet how warn the operating theatre is. Cats under general anaesthetic are prone to hypothermia, but Decreased incidence of perioperative inadvertent hypothermia and faster anesthesia recovery with increased environmental temperature: a nonrandomized controlled study (2020) Rodriguez-Diaz J, Hayes GM, Boesch J, Martin-Flores M, Sumner JP, Hayashi K, Ma E & Todhunter RJ Veterinary Surgery 49(2) pp256-264 found that if the operating room temperature was 75°F (24°C), it reduced the incidence of hypothermia by over 50%.
Intravenous Fluids
All cats should be placed on intravenous (IV) fluids during and after any procedures. This is to avoid falls in blood pressure during the procedure, which may damage the kidneys (see above).
CKD cats should also be placed on intravenous fluids for a few hours before any surgery. Not every vet wishes to place a CKD cat on IV fluids before anaesthesia, but this is very important for your cat’s safety. In Chronic kidney disease (2007) Polzin DJ Delaware Valley Academy of Veterinary Medicine, Dr Polzin (a kidney specialist) states “It appears that the medical prophylaxis most likely to be effective is related to pre-intervention fluid support. Pre-loading patients with fluids before potential ischemic or nephrotoxic interventions has thus far been shown to be the most effective therapy. Other options that have been investigated include diuretics, vasodilators, and some forms of metabolic support. However, none have thus far proven to be superior to support with a saline-based fluid. Usually, fluids should be administered in sufficient volume to induce diuresis.”
AAFP feline anesthesia guidelines (2018) Robertson SA, Gogolski SM, Pascoe P, Shafford HL, Sager J & Griffenhagen GM Journal of Feline Medicine and Surgery 20(7) pp602-634 are quite technical but have a section about anaesthesia in CKD cats which states “Preanesthetic fluid therapy may be of value to restore normovolemia and hydration.”
2013 AAHA/AAFP fluid therapy guidelines for dogs and cats (2013) Davis H, Jensen T, Johnson A, Knowles P, Meyer R, Rucinsky R & Shafford H Journal of the American Animal Hospital Association 49(3) pp149-159 state “patients with uremia benefit from preanesthetic fluid administration.”
Depending upon the type of surgery involved, antibiotics may need to be given to the cat for several days in advance, and continued for 5-7 days afterwards.
10 questions to ask your veterinary health care provider when your animal needs general anesthesia Narkovet Consulting helps you plan for surgery.
During Surgery
All cats should be placed on IV fluids during and after any procedures. This is to avoid reduced blood flow and falls in blood pressure during the procedure, which may damage the kidneys. Perioperative anaesthetic care of the cat undergoing dental and oral procedures: key considerations (2015) De Vries M & Putter G Journal of Feline Medicine and Surgery 17 pp23-36 states “It is recommended that IV fluids are provided during anaesthesia, not only to compensate for ongoing losses and potential haemorrhage but also to counteract any relative hypovolaemia resulting from anaesthetic agent-induced hypotension.”
This is even more important for CKD cats. Anesthesia for patients with renal disease (2015) Rezende M & Mama K Clinician’s Brief Mar 2015 pp41-44 states “The kidneys are particularly susceptible to ischemic injury because the distribution of blood flow within the kidneys is not uniform or proportional to demand; despite its higher metabolic rate, for example, the renal medulla only gets 15% of the overall renal blood flow (RBF). Therefore, a decrease in cardiac output and blood pressure— as may be observed with anesthetic drug administration—has the potential to further compromise renal function.” They go on to say “vascular volume and blood pressure support remain the most important aspects of protecting renal function during anesthesia management.”
The American Association of Feline Practitioners Senior Care Guidelines (2009) Pittari J, Rodan I, Beekman G, Gunn-Moore D, Polzin D, Taboada J, Tuzio H & Zoran D Journal of Feline Medicine & Surgery 11 pp763-778 gives guidance on anaesthesia for older cats, especially those with CKD.
What monitors can and can’t tell you: real world monitoring for field and high volume anaesthesia (2014) McCobb E Pet Smart Charities National Spay/Neuter Conference gives an overview of standard monitoring procedures which can give you some idea of the basics.
Any drugs used on a CKD cat during anaesthesia which are cleared by the kidneys may require a reduction in the dose, since damaged CKD kidneys may not clear them as fast as healthy kidneys.
Anesthetic hypotension (2017) Jimenez Lozano MA Clinician’s Brief Mar 2017 pp27-30 discusses steps your vet can take should your cat’s blood pressure fall too low during the procedure.
Anaesthetic Choices
The main concern during the surgery is often the anaesthetic. You should discuss with your vet the type of anaesthesia that will be used on your cat. Generally speaking, animals undergoing surgery receive two types of anaesthesia:
- an induction agent to induce unconsciousness; and
- general anaesthesia to keep them unconscious whilst the procedure is being performed.
Anaesthesia for the geriatric dog and cat (2008) Hughes JML Irish Veterinary Journal 61(6) pp380–387 discusses the use of anaesthesia in older cats, including cats with kidney disease.
Renal disease management basics (2004) Stein B Veterinary Anesthesia and Analgesia Support Group recommends a particular anaesthesia protocol for patients with kidney disease. Ask your vet to follow this, or to explain any changes to you.
No more kidney around: anesthesia and the renally impaired cat (2019) Cooley K firstline discusses safe anaesthetic choices for CKD cats.
Anesthesia for patients with renal disease (2015) Rezende M & Mama K Clinician’s Brief Mar 2015 pp41-44 discusses anaesthetics which are suitable for CKD cats.
The Veterinary Anesthesia and Analgesia Support Group provides information on anesthesia protocol generally.
Induction Agents
Induction agents used in cats are usually in the form of injections. A commonly used induction agent is propofol.
Veterinary Anaesthesia and Analgesia Support Group mentions that “alfaxalone has little or no cardiovascular effects when given in the normal dose.” This might make it a better choice for a cat with heart disease.
Ketamine is not recommended because it has to be cleared by the kidneys.
Some vets do not use an injectable induction agent, but instead use an inhaled anaesthetic both to induce unconsciousness and to provide general anaesthesia. Using inhaled anaesthetics in this way is sometimes referred to as “masking down.” I would ask your vet not to do this, because injected induction agents are safer. Serenity now: practical sedation options for cats (2015) Shafford HL, a veterinary anaesthetist, says “Box inductions should be avoided because they are 1) scary and stressful for patients, 2) dangerous to personnel (exposure to inhalants associated with numerous adverse health effects including impaired reproductive function), and 3) dangerous to the patient (exposure to high levels of potent cardiorespiratory depressant, inability to monitor and support cardiovascular or respiratory system during induction, increased mortality).”
General Anaesthetics
General anaesthetics take various forms. Although inhaled anaesthetics are not the best choice for induction purposes, as general anaesthetics they can be a good choice for CKD cats. These are gases, which put less strain on the cat’s body than other types of anaesthetic, and they also enable the vet to stop the procedure and bring your cat round immediately if there are any problems during surgery.
One commonly used inhaled anaesthetic is isoflurane. Some vets prefer another inhaled anaesthetic called sevoflurane, but Anesthesia for patients with renal disease (2015) Rezende M & Mama K Clinician’s Brief Mar 2015 pp41-44 states “Because of the known nephrotoxic metabolites (eg, compound A) produced by sevoflurane, it is best to avoid this drug even though any toxic effect may be minimal in a stable patient with renal disease. Therefore, the use of isoflurane is generally recommended.”
If your cat is to receive an inhaled anaesthetic following induction with an injectable induction agent, usually an endotracheal tube is inserted into the cat’s throat to administer the inhaled anaesthetic and to help the cat to breathe.
The main downside of inhaled anaesthetics is that they may cause low blood pressure, which can damage the kidneys. It is therefore essential that your cat’s blood pressure is monitored during the procedure and that intravenous fluids are given before, during and after the procedure.
After Surgery
Your cat should be monitored closely after surgery. AAFP feline anesthesia guidelines (2018) Robertson SA, Gogolski SM, Pascoe P, Shafford HL, Sager J & Griffenhagen GM Journal of Feline Medicine and Surgery 20(7) pp602-634 state that “Sixty percent of all anesthetic-related cat deaths occur during the recovery period, especially the first 3 h.”
The risk of death: the confidential enquiry into perioperative small animal fatalities (2008) Brodbelt DC, Blissitt KJ, Hammond RA, Neath PJ, Young LE, Pfeiffer DU & Wood JL Veterinary Anaesthesia & Analgesia 35(5) pp365-73 states that “Greater patient care in the postoperative period could reduce fatalities.”
Some cats develop a low temperature during or following anaesthesia. Perioperative anaesthetic care of the cat undergoing dental and oral procedures: key considerations (2015) De Vries M & Putter G Journal of Feline Medicine and Surgery 17 pp23-36 states “Cats are prone to hypothermia due to their high body surface area to volume ratio. Unfortunately, the importance of body temperature monitoring and support is largely still underestimated in veterinary medicine.” Also see above for the optimal temperature in the operating room.
Therefore you should ensure that your cat’s temperature is closely monitored after surgery. Some vets warm the fluids given to the cat but Heated intravenous fluids alone fail to prevent hypothermia in cats under general anaesthesia (2017) Jourdan G, Didier C, Chotard E, Jacques S & Verwaerde P Journal of Feline Medicine and Surgery 19(12) pp1249-1243 found that “heated fluid alone fails to prevent intraoperative hypothermia in cats.” It speculates that this might have been the case in this study because of the low infusion rate of 5 ml per kg of cat per hour.
Your cat might benefit from a heat pad immediately following surgery. The American Association of Feline Practitioners Senior Care Guidelines (2009) Pittari J, Rodan I, Beekman G, Gunn-Moore D, Polzin D, Taboada J, Tuzio H & Zoran D Journal of Feline Medicine & Surgery 11 pp763-778 states “Since hypothermia is common, evaluate body temperature every 15 mins, continuing postoperatively until the cat is ambulatory or normothermic. Support body temperature by using tools such as a heated cage, hot air blankets, water-circulating heating pad, and/or booties.” If your vet uses a heat pad, this should only be used once the cat is able to move off the pad of his/her own volition should they start to feel too hot.
Your cat should also receive intravenous fluids during the recovery period. The Winn Feline Foundation (2020) is funding research into the effects of general anaesthesia on kidney function in cats and whether intravenous fluids may reduce these effects, but in the meantime 2013 AAHA/AAFP fluid therapy guidelines for dogs and cats (2013) Davis H, Jensen T, Johnson A, Knowles P, Meyer R, Rucinsky R & Shafford H Journal of the American Animal Hospital Association 49(3) pp149-159 state “Patients that may benefit from fluid therapy after anesthesia include geriatric patients and patients with either renal disease or ongoing fluid losses from gastrointestinal disease.”
Anaesthesia for the geriatric dog and cat (2008) Hughes JML Irish Veterinary Journal 61(6) pp380–387 also states “All recovering geriatric patients should receive oxygen supplementation and be monitored closely until their protective pharyngeal reflexes have returned.”
Blood pressure should also be monitored for a week or so afterwards because although low blood pressure is a risk during surgery, surgery and anaesthesia may cause increases in blood pressure following the procedure.
If inhaled anaesthesia has been used, your cat will have a tube down the throat during surgery (intubation), which can cause the throat to feel a little sore for a day or two afterwards.
After most types of surgery painkillers are necessary. WSAVA guidelines for recognition, assessment and treatment of pain (2014) Mathews K, Kronen PW, Lascelles D, Nolan A, Robertson S, Steagall PVM, Wright B & Yamashita K Journal of Small Animal Practice 55(6) ppE10–E68 points out that “pain associated with surgery is 100% predictable.”
Your cat may be able to come home a few hours after surgery, or may have to stay in the hospital overnight or for a day or so. If you bring him or her home soon after surgery, keep him/her in a warm, quiet place. Your cat may be a little wobbly at first, but this should soon improve. If you have any concerns, contact your vet.

This page last updated: 11 November 2020
Links on this page last checked: 02 May 2020