Hit-by-car trauma: the first response at the scene

Hit-by-car (HBC) is the single most common cause of severe trauma I see in my emergency practice. The good news is that survival rates for HBC patients have improved dramatically in the last 20 years — from below 30% to over 80% in some centres, thanks to better trauma protocols, blood products, and surgical techniques. The bad news is that the cases that don't make it almost always share one feature: the first response at the scene made the injuries worse.

This article is about the 10 minutes that decide whether your dog or cat lives.

First: assess safety

Before you run to the pet, check the scene. A second car is the most common additional casualty in HBC incidents.

Is traffic still moving around the pet? If yes, you need to move yourself and the pet out of the roadway. Flag down traffic, turn on hazard lights, send someone to flag traffic further up the road

Is there leaking fluid (fuel, oil)? Move the pet away from fuel and oil. Both are toxic and flammable

Is the animal in a place where you can safely approach? A frightened or painful dog may bite, even one that has never bitten before

If the scene is unsafe, wait for emergency services. A dead owner does not save a dead pet.

Approach the pet carefully

An injured, frightened dog or cat in pain is dangerous. Even the most gentle family dog can bite when hit by a car. Approach with these precautions:

Move slowly, talking in a low voice

Have a towel or blanket ready to throw over the pet if needed

Avoid direct eye contact (perceived as threatening by a stressed animal)

Approach from the side, not from the front or behind

Be ready to retreat if the pet shows aggressive warning signs (snarling, growling, ear pinning)

If the pet cannot be safely approached and is in danger (in the road, near traffic), call animal control or the non-emergency police line for assistance. Don't risk your life.

Initial assessment: 30-second triage

Once you are at the pet, do a rapid ABCDE assessment:

A: Airway

Is the pet's airway clear? Open the mouth, pull the tongue forward, look for blood, debris, vomit. If the pet is unconscious, clear the airway before anything else.

B: Breathing

Watch the chest. Is it rising and falling? How fast? A normal dog breathes 15–30 times per minute; a normal cat 20–40. Fast, shallow breathing suggests pain or shock. No breathing means cardiac arrest — begin CPR.

C: Circulation

Check the gums. Pink gums = good perfusion. Pale, white, or grey gums = shock or severe blood loss. Press a finger on the gum; colour should return within 2 seconds. Longer refill time = poor circulation.

Feel the femoral pulse (in the groin). Fast and weak = shock. Absent = cardiac arrest.

D: Disability (neurological)

Are the pupils equal in size? Are they responsive to light? Unequal pupils or unresponsive pupils suggest head injury or shock.

Can the pet move its limbs? Paralysis, especially of the hind limbs, suggests spinal injury. Be very careful moving the pet if paralysis is present.

E: External bleeding

Look for obvious bleeding. The most common sites are:

Mouth or nose: usually indicates chest injury or head trauma

Limbs: usually visible wounds

Abdomen: internal bleeding may not be visible externally but the abdomen may be distended

What to do for visible external bleeding

For limb or body wounds:

Apply direct pressure with a clean cloth, towel, or even a t-shirt

Maintain pressure for at least 5–10 minutes. Do not lift the cloth to check — you will disrupt clot formation

If bleeding soaks through, add more cloth on top rather than removing the original

Elevate the bleeding limb above the heart if possible without moving the pet more than necessary

For severe limb bleeding that does not respond to pressure:

A tourniquet is a last resort. Apply only if bleeding is life-threatening and direct pressure fails

Use a wide band (not thin rope or wire — these damage tissue)

Note the time of application

Loosen the tourniquet every 10 minutes to allow some circulation

Most HBC bleeding is controllable with direct pressure. Tourniquets are rarely needed and often cause more damage than they prevent.

Moving the pet to the car

The most common error I see at the scene is improper lifting. Pet owners often pick up the pet like a baby — cradling the abdomen and supporting the hindquarters. For a pet with suspected spinal injury or internal bleeding, this can be lethal.

The correct lift:

Slide a flat board, blanket, or coat underneath the pet. A large towel works for cats and small dogs. A flat piece of wood, a baking sheet, or a car sun visor works for medium dogs. A large blanket or plywood panel works for large dogs.

Have one person at the head, one at the hips. Lift together, keeping the pet's spine in a neutral position.

Carry flat to the car, not draped. The pet's body should remain horizontal and supported the entire time.

Place on a flat surface in the car — the back seat floor, the cargo area, or a flat board across the back seat.

If you are alone, the emergency lift is:

Grasp the pet's skin over the back of the neck and over the rump (the loose skin there)

Lift and drag onto a blanket or board

Drag the blanket with the pet on it to the car

Lift into the car

This is not ideal but is better than lifting a 30 kg dog with possible spinal injury by cradling.

What NOT to do at the scene

A list of the errors that complicate emergency treatment or worsen injuries:

1. Do not give food or water

The pet may need sedation or anaesthesia. Anaesthesia on a full stomach risks aspiration (vomit into the lungs). Even water is avoided in case surgery is needed.

2. Do not attempt to set broken bones

You will worsen the fracture, may damage nerves and blood vessels, and will cause severe pain. Splinting in the field is appropriate only for obvious limb fractures during transport, and only if the splint does not require moving the limb further.

3. Do not clean wounds aggressively

A quick rinse to remove visible debris is fine. Aggressive scrubbing or pouring hydrogen peroxide into wounds causes tissue damage and bleeding. The emergency vet will clean properly under sedation.

4. Do not give over-the-counter pain medications

Human pain medications are toxic to pets:

Ibuprofen (Advil): causes kidney failure and GI ulceration in dogs

Acetaminophen (Tylenol): toxic to cats at any dose, toxic to dogs at high doses (liver failure)

Aspirin: causes GI bleeding and is not a great analgesic for acute trauma pain

Pain relief is important but only after the vet has assessed the pet.

5. Do not delay transport to "stabilise" the pet

The pet's internal injuries are best assessed by the emergency vet, not in the field. Stabilisation is something the emergency team does with IV access, oxygen, and pain medication. The best thing you can do at the scene is get the pet to the vet quickly and safely.

6. Do not assume the pet is OK because it can walk

Cats and dogs with severe internal injuries often walk away from the scene. Internal bleeding, pulmonary contusions (bruised lungs), and diaphragmatic hernia can all present with a pet that is walking but dying internally. Any pet hit by a car needs veterinary assessment even if it appears fine.

Calling ahead

If you have a passenger or can call hands-free, call the emergency vet while en route. Tell them:

Animal hit by car (or whatever mechanism)

Approximate weight (small, medium, large)

Visible injuries (bleeding, limping, unresponsive)

Time of incident

Estimated time of arrival at the clinic

This allows the emergency team to prepare — IV catheter, fluids, oxygen, blood products, surgical team on standby.

What the emergency vet will do

The first hour at the emergency clinic follows a standard trauma protocol:

Primary survey: ABCDE again, plus rapid assessment of major bleeding

IV catheter and fluid resuscitation: large-bore catheter, isotonic crystalloid (LRS or Plasmalyte), shock dose if indicated

Pain control: opioid (methadone, hydromorphone) — much safer than NSAIDs in trauma

Bloodwork: PCV/TS (haematocrit), lactate, electrolytes, blood gas

Imaging: chest X-rays (looking for pulmonary contusion, pneumothorax, diaphragmatic hernia), abdominal ultrasound (FAST scan for internal bleeding), orthopaedic X-rays if limb injury suspected

Stabilisation based on findings: oxygen, chest tube, blood transfusion, surgery if indicated

For a stable pet with minor injuries: treat wounds, monitor for 24 hours, go home with rest and pain medication.

For an unstable pet: hours to days of hospitalisation, potentially surgery, recovery over weeks.

For a pet with severe injuries (especially cats with severe trauma): humane euthanasia may be the kindest option. The emergency vet will discuss this honestly with you.

Survival rates by injury type

Based on published veterinary trauma data:

| Injury | Survival rate with treatment |

|---|---|

| Soft tissue wounds only | >95% |

| Single long bone fracture | >90% |

| Multiple fractures | 70–85% |

| Pulmonary contusion | 60–80% |

| Pneumothorax | 70–90% with chest tube |

| Diaphragmatic hernia | 50–80% depending on chronicity |

| Splenic laceration | 70–90% with splenectomy |

| Liver laceration | 50–70% |

| Head trauma (severe) | 30–60% |

| Spinal fracture with paralysis | 20–50% depending on location |

| Cardiac tamponade | <30% |

The data varies by region and clinic. The trend over the last 20 years has been significant improvement in survival for most categories.

Prevention

The single biggest prevention measure is restraint:

Cats should be indoor-only. Outdoor cats have a dramatically higher risk of HBC

Dogs should be on leash near roads. The backyard should be securely fenced

Driveway awareness. Dogs under or behind a car in a driveway are a common HBC scenario

Training for reliable recall. A dog that comes when called can be recalled away from roads

Visibility: reflective collars and harnesses for evening walks reduce HBC risk

The bottom line

HBC is a high-stakes emergency. The first 10 minutes at the scene determine the next 10 days of medical care. Approach safely, do a rapid ABCDE assessment, control visible bleeding with direct pressure, lift the pet flat onto a board or blanket, do not give food or water, transport to the nearest emergency clinic, and call ahead. The cases that survive are the cases where the owner did the basics right at the scene and got the pet to the vet quickly. The cases that don't are the ones where well-meaning intervention — feeding, water, improper lifting, unapproved pain meds — made the injuries worse before the vet could help.

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About the author: [Dr. Sofia Martinez](../Sofia%20Martinez.md), DVM, CertECC, is a UCM-trained veterinarian with 13 years of practice and former head of emergency surgery at Hospital Veterinari 24h in Barcelona.