When nutrition is critical: preventing malnutrition in hospital

Did you know that patients of any age can become malnourished from inadequate nutrient intake? Malnutrition is defined as any disorder with inadequate or unbalanced nutrition associated with either nutritional deficiencies or excesses. This can occur in a variety of ways, but we often see patients come through to the clinic already in some state of malnutrition, especially in critical cases. Some patients may then become further malnourished while in hospital as a result of their disease or conditions, therefore nutrition should be a cornerstone of every patient’s treatment while in our care.

Nutrition should always form part of a patient’s care plan at admission to hospital.

Risk factors for developing malnutrition:

  • Patients who lack appetite or lack the ability to eat
  • Nutrient losses through diarrhea or vomiting
  • Patients with wounds and/or burns
  • Diseases that can impact appetite such as renal disease, diabetes, thyroid disease or pancreatitis
  • Patients with unintentional weight loss that exceeds 10% bodyweight
  • Oral intake disrupted for more than 3-5 days (intervene sooner in patient under 6 months of age)
  • Patients eating unconventional or unbalanced diets (home cooking, raw, etc) without guidance from a veterinary nutritionist
  • Some forms of cancer
  • Some medications that change appetite or interfere with absorption of nutrients

So how can we support our patients in hospital through to discharge to ensure they are getting the best nutrition possible to improve their outcomes and ensure they do not become malnourished while in hospital undergoing treatment? Firstly, every patient should receive a nutritional assessment upon admission to hospital, including an assessment of any nutritional risk factors (as above) that may impact their health. Every patient should be Body and Muscle Condition scored at admission, and have an RER/DER calculated to form a feeding plan for their hospital stay. This information needs to be included in the animal’s care plan. It’s also important that we continue to regularly monitor these parameters (weight, daily intake of food, BCS/MCS) while the patient is in hospital to ensure they are not deteriorating. The feeding plan can be reevaluated throughout the pets stay and at discharge, depending on their particular circumstances.

Goals of nutritional support in critical cases:

  • Support immunity to prevent secondary or hospital-acquired infections.
  • Provide the building blocks for tissue repair and synthesis to promote wound healing
  • Promote normal metabolic processes through the provision of energy-dense food to allow for normal drug metabolism
  • Maintain body condition which is linked to better patient outcomes
Proper nutrition can ensure a smooth and successful recovery from surgery or a hospital stay.

So when providing a diet in hospital, what Key Nutritional Factors are we looking for?

Select a complete and balanced diet that provides all the necessary nutrients for the pet in a highly digestible and highly palatable form. You are looking for either a prescription diet designed for inpatient use (eg Hills a/d or i/d, Royal Canin Recovery or ProPlan CN) or a diet with 10-20% carbs, 40-50% fat and 40-50% protein. Typically only a therapeutic diet will contain these levels, however some diets may still be suitable for short term use, if you intend on sending the patient home with the recovery diet and do not want to trigger food aversions by feeding it in hospital. Carbs are restricted in convalescent diets as they are poorly utilized in sick pets as a source of glucose – fat is a lot more energy dense and is readily available. Fats are high in these diets for this reason, in addition to increasing the palatability of the diet to encourage food intake in sick pets, fats can provide a source of essential fatty acids and aid in the absorption of fat-soluble vitamins. For pets that are suffering from fat sensitive diseases (such as pancreatitis or GI conditions), a low fat alternative can be used and most of these therapeutic diets will have a low fat version you can use. Protein of high quality and digestibility is also in relatively high proportions in these diets; this is important in maintaining muscle condition, providing a source of amino acids to aid recovery and overcome muscle wastage that recumbent patients may be at risk for. A diet high in moisture such as a wet diet is also a good choice, as in most cases it is easier and less energy heavy to digest. It’s also suitable for patients who are unwilling or unable to drink and could do with the extra hydration. These patients should never be fed raw meat due to their impaired immunity and potential for severe infection to occur. In majority of cases, these patients are also not good candidates for a home cooked diet due to changes in taste perception (making it hard to actually get them to eat and accept the food) and potential for any underlying or early deficiencies to be exacerbated.

Getting sick pets to eat can be as frustrating as it is rewarding

Of course, a diet is only going to work if the pet eats it. As a result of some of the conditions described above that place pets at risk of malnutrition, these patients may not want to eat. Particularly renal patients, those with dental disease or oral pain, or pets with gastrointestinal pain may become nauseated in the presence of food or refuse to eat on their own. Voluntary oral intake of food is always preferred to more invasive techniques, so here are some techniques to try and stimulate oral food intake in hospitalised pets:

  • Calm stress free environment: cats like a hiding place, dogs may like to eat somewhere other than their kennel
  • Increase palatability: gently warm food to below body temp as this enhances the smell, choose a suitable food
  • Increase moisture: wet diets are often preferred
  • Use fresh food, right out of the package
  • Provide one type of food at a time: too many foods can lead to food aversions
  • Some animals may benefit from an appetite stimulant in the short term (your vet will advise if this is suitable)

If these techniques fail, and your patient will not eat anything for three days, a feeding tube should be considered to avoid malnutrition and anorexia progressing.

What is your go-to diet for critical patients? What’s your clinic’s protocol for patients at risk of malnutrition?


Saker & Remillard (2019) Critical Care Nutrition and Enteral Assisted Nutrition. Chapter 25. Small Animal Clinical Nutrition 5th Ed. Mark Morris Institute. Available online at: http://www.markmorrisinstitute.org/sacn5_download.html

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