Canine First Aid: Primary Survey

Showing where to locate the mucous membranes in a dog

Primary Survey -Evaluating the Mucous Membranes:


In canine first aid, the emergency responder should be able to make a rapid, primary survey of the dog. This is designed to help detect immediate threats to life so that they can be dealt with first.  Immediate life threats typically involve the dog’s Airway, Breathing and Circulation.

Evaluating the mucous membranes is an extremely useful technique to learn when carrying out canine first aid. It provides vital insights on the condition of the dog’s circulation and also helps assess their state of health.

What is a mucous membrane?

A mucous membrane is a moist, inner lining, found in certain body cavities and organs. It has a network of blood vessels and glands within it make mucus (a thick, slippery fluid). Also called mucosa. A healthy mucous membrane should look pink, shiny and moist.

The most frequently used, and easiest to assess, are the oral mucous membranes around the gums, observed by gently lifting the dog’s lip in the region of its canine tooth.

The conjunctiva (the inside lining of the eye) may also be used by gently pulling the bottom lid down.

Making an assessment of the mucous membranes in canine first aid situations

This includes making observations of the following:

  • Assess the colour

The mucous membranes should be a health pink colour. However this can vary amongst dogs. For example Chow Chows can have a lot of black pigmentation in the mouth, making it more difficult to assess the colour and some breeds have naturally pinker membranes. It makes sense to observe your own dog’s mucous membranes whilst they are well and healthy to see what they look like normally. Check them when they are resting and not just after a session of heavy exercise.

  • Pale mucous membranes can indicate advanced shock and blood loss.
  • A brick red colour can be associated with sepsis or heatstroke (hyperthermia). See image.
  • A blue tinge (known as cyanosis) or a “muddy” appearance can indicate a lack of oxygen in the bloodstream. See image.
  • Dental problems and gum disease may result in inflammation which can alter the appearance of the gums. However, this change usually develops over time and is accompanied by a bad breath. Learning how to brush your dog’s teeth is one way to prevent problems.
Image shows a brick red mucous membrane
An example of what a brick red mucous membrane looks like

Cyanosis of the mucous membranes

  • Evaluate the capillary refill time (CRT)

This is performed by briefly pressing down on their gum with your finger in order to displace the blood in the vessels until it turns white.  You then release your finger, taking note of the time for the area to turn pink again. This is the time it takes for the blood to flow back in to the vessels. Normal capillary refill time is less than 2 seconds. A delay indicates that the circulation is affected. Conditions that cause a slow CRT include: haemorrhage, shock and hypothermia (a decrease in body temperature).

  • The degree of moisture

The mucous membranes should be moist and the lip should glide easily against it. If they are tacky or dry it may indicate dehydration which occurs in a number of conditions including prolonged diarrhoea, vomiting and heatstroke.

In dog first aid, being able to evaluate the state of the casualties mucous membranes is an extremely useful skill to learn. It is quick, easy and provides valuable information about conditions that are an immediate threat to life. To become an canine first aider and gain an accredited certificate please click HERE for details. And, if you want to learn more about canine health, for details of the accredited Higher Certificate in Canine Health and Welfare click HERE 

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