Your Pet’s Kidneys Crashed After Surgery. Now What.

Quick answer

If you are reading this at 2 am while watching your pet breathe shallowly after surgery, you are not overreacting. A post-surgical kidney crash—known medically as acute kidney injury—is a serious emergency, but with immediate veterinary intervention and aggressive intravenous fluids therapy, many dogs and cats can make a full recovery.

If your dog or cat is facing acute kidney injury (AKI) after anesthesia or surge

:::key-facts

• Time is critical: The sooner your pet receives intravenous fluids to flush out toxins, the better their prognosis.
• It is not your fault: Post-op kidney crashes are usually caused by unpredictable drops in blood pressure during anesthesia, not owner neglect.
• Monitoring is key: Tracking urine output, hydration levels, and appetite is vital during the recovery phase.
• Reversible damage: Unlike chronic kidney disease, acute kidney injury can often be reversed if caught and treated early.
  :::

Why it matters

It is incredibly heavy to watch your pet go in for a routine procedure and come out fighting for their life. Please know this: you did nothing wrong, and your veterinary team did not do this on purpose.

During anesthesia, a pet’s blood pressure can naturally drop. This condition, called hypotension, reduces the flow of oxygen-rich blood to vital organs. The kidneys are highly sensitive, blood-thirsty filters. If their blood supply is restricted for even a brief period during surgery, or if they have an underlying sensitivity to pre-surgical pain medications like non-steroidal anti-inflammatory drugs (NSAIDs), the kidney cells can suffer sudden, acute damage. This sudden shutdown is called acute kidney injury.

When the kidneys crash, they stop filtering waste products like blood urea nitrogen (BUN) and creatinine from the bloodstream. These toxins build up rapidly, making your pet feel incredibly nauseous, weak, and disoriented. Understanding this mechanism helps you see why immediate hospitalization is not just recommended—it is lifesaving.

:::ask-boo
Why did my pet's blood pressure drop during surgery?
:::

What good looks like

When your pet is receiving the right treatment, you will see a gradual, steady turnaround. In the hospital, "good" looks like a pet whose kidney values on daily blood tests are trending downward toward normal ranges.

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Continuous intravenous fluids in a hospital setting are the cornerstone of treating acute kidney injury.
:::

At home, a recovering pet should be bright, alert, and increasingly interested in food. Their hydration levels will stabilize, their gums will feel wet and pink rather than dry and tacky, and they will produce a normal, steady volume of urine. They will transition from a state of profound lethargy back to their usual, curious selves, even if they need to take things slow for a few weeks.

Step-by-step

If your vet has confirmed or suspected a post-surgical kidney crash, here is the exact roadmap of what needs to happen next to give your pet the best chance at recovery.

Step 1: Hospitalization and IV Fluid Therapy

Your pet must be admitted to a veterinary hospital immediately. Subcutaneous fluids (fluids injected under the skin) are not enough for a true kidney crash. They require precise, continuous intravenous fluids delivered via an IV catheter. This directly flushes the kidneys, restores blood pressure, and helps clear the buildup of toxic waste products from the blood.

Step 2: Monitor Urine Output

Your vet will closely monitor how much urine your pet is producing. In some severe cases of acute kidney injury, the kidneys stop producing urine entirely (anuria) or produce very little (oliguria). If the kidneys are receiving fluids but not producing urine, the body will fluid-overload, which is highly dangerous. Your vet may place a urinary catheter to measure output down to the milliliter.

Step 3: Daily Blood Chemistry Panels

Expect your vet to run daily blood tests to check creatinine, blood urea nitrogen (BUN), and electrolytes like potassium and phosphorus. You want to see these numbers peaking and then steadily declining. Do not be discouraged if they do not drop instantly on day one; sometimes it takes 48 to 72 hours of fluid therapy to see a positive trend.

Healthy gums should be pink and moist; dry or tacky gums are a key indicator of dehydration.

Step 4: Supportive Medications

While the fluids do the heavy lifting, your pet will likely need medications to manage the severe nausea and stomach ulcers associated with kidney crashes. Your vet may administer anti-nausea medications (like [maropitant](</p/knowledge/drugs/maropitant>)), gastroprotectants, and appetite stimulants to encourage them to eat as their kidneys recover.

:::pro-tip
When your pet comes home, place multiple water bowls around the house or use a pet water fountain. Keeping them hydrated is the single most important thing you can do to protect their recovering kidneys.
:::

Step 5: Transitioning to Home Care

Once your pet's blood values have stabilized and they are eating on their own, they can come home. You will need to monitor their water intake, feed them a highly palatable, easily digestible diet (sometimes a temporary prescription kidney diet), and administer any prescribed oral medications exactly as directed.

The skin tent test: if the skin remains tented or returns to place slowly, your pet is dehydrated.

Signs something's wrong

When your pet is recovering at home, you must act as their guardian. The kidneys can sometimes suffer secondary setbacks, or the recovery can stall. You need to watch for subtle and obvious signs that their kidney function is slipping again.

Keep a close eye out for:

• Profound lethargy: If your pet cannot lift their head, refuses to stand, or seems completely unresponsive.
• Repeated vomiting: A single vomit might be a dietary hiccup, but continuous vomiting means toxins are building up in the blood again.
• Changes in urination: If your pet is straining to urinate, producing no urine at all, or suddenly drinking and urinating in massive, abnormal quantities.
• Uremic breath: A distinct, foul, chemical, or ammonia-like smell coming from your pet's mouth.
• Complete refusal to eat: Missing one meal is common after hospital discharge, but refusing food for more than 24 hours is a red flag.

:::warning
If your pet stops producing urine entirely, begins vomiting uncontrollably, or experiences seizures, this is a red-flag emergency. Their kidneys may have stopped functioning completely, causing a life-threatening buildup of potassium. Go to an emergency vet clinic immediately.
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When to call your vet

You should never hesitate to call your vet if you feel something is off. However, you must contact them immediately if you notice:

• Your pet has not urinated in 12 hours.
• Your pet refuses to drink water or cannot keep water down.
• Their gums feel dry, sticky, or tacky to the touch (a sign of worsening dehydration).
• They show signs of extreme weakness, such as hind-limb wobbliness or collapse.
• You notice any swelling in their face, paws, or legs (which can indicate fluid overload or poor circulation).

:::ask-boo
How long can a dog or cat go without urinating after surgery?
:::

Common mistakes

When dealing with a highly stressful medical crisis, it is easy to make well-intentioned mistakes. Avoiding these common pitfalls will help keep your pet safe:

• Giving pain medications at home without consulting your vet: Never give leftover post-op pain medications (especially NSAIDs) if your pet is not eating, drinking, or if you suspect kidney issues. These drugs can severely worsen acute kidney injury.
• Restricting water to prevent accidents: If your pet is urinating frequently inside the house, do not take their water bowl away. Their kidneys currently require massive amounts of water to function. Restricting water can cause an immediate, fatal crash.
• Assuming "they are just tired from surgery": While some post-op sleepiness is normal, profound weakness and refusal to stand are not. Do not wait out these symptoms; assume it is an emergency until proven otherwise.
• Stopping medications early: Even if your pet seems completely back to normal, finish every single dose of medication prescribed by your vet unless they explicitly tell you to stop.

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Encouraging continuous hydration at home is vital for supporting recovering kidney tissues.
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Quick FAQs

Can a pet's kidneys fully recover from a post-surgical crash?

Yes. Unlike chronic kidney disease, which is a gradual, irreversible loss of function, acute kidney injury involves sudden damage. If the underlying cause is addressed quickly with IV fluids, the remaining healthy kidney cells can often compensate, and damaged cells can regenerate over weeks or months.

How long will my pet need to stay in the hospital?

Most pets hospitalized for a post-surgical kidney crash require between 3 to 7 days of continuous intravenous fluids therapy, depending on how quickly their blood values stabilize.

Is a kidney crash always the vet's fault?

No. While it is incredibly frustrating, anesthesia carries inherent risks for every living being. Even with perfect monitoring, pre-operative bloodwork, and active fluid therapy during surgery, some pets experience unpredictable drops in blood pressure or idiosyncratic drug reactions that lead to kidney injury.

:::ask-boo
What is the survival rate for pets with post-surgical acute kidney injury?
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Summary of hope

It is completely natural to feel overwhelmed, scared, and even angry right now. You chose to get surgery to help your pet, and facing this complication is incredibly painful. But please take a deep breath: you are doing the right thing by educating yourself and acting quickly.

By keeping a close eye on their hydration, partner-shipping with your veterinarian for aggressive fluid therapy, and monitoring their recovery step-by-step, you are giving your beloved companion the best possible chance to heal. The kidneys are remarkably resilient, and with your dedicated care, this terrifying chapter can soon become a distant memory.