CRITICAL CARE
3. CALORIC needs
Critically ill patients should start receiving RER as soon
as they are haemodynamically stable.3,4 Previously RER
was multiplied by an illness factor to provide higher
energy levels.7 This practice was discontinued, as it
was shown that it is not necessary to feed patients
more than RER and may in fact be detrimental.2,3,4
Should it become evident that a patient requires more
nutrition than what is being provided – weight changes, ongoing losses (vomiting and diarrhoea) - the
number of calories can be increased by up to 25% at
a time.3
The resting requirements are calculated using
one of the following formulae7:
•
Fig 1: A cat with a nasoenteric tube placed. A collar is placed to
prevent the patient from dislodging the tube. (Photograph Courtesy Dr van Schoor. Onderstepoort Veterinary Academic Hospital)
by artificial means, when to commence feeding, how
much food to supply, how often to feed, the type of
food to feed, which route of nutrient supply to use,
and how to monitor the nutritional status of the patient. This all forms part of the nutritional plan.
•
For animals > 2kg <30kg body weight (BW) –
linear formula:
°° [BW x 30] +100 = kcal/24hours
For all animals <2kg and >30kg – allometric formula
°° 100 x (BW)0.75 = kcal/24 hours
Alternatively, the WSAVA RER chart can be used to determine the RER of the patient based on its body weight.
1. ASSESS nutritional status
4. ROUTE of administation
A subjective assessment is made in order to decide
on the nutrition of a critically ill patient.4 This includes
a history of a loss of appetite, weight loss observed
by the owner and the presence of vomiting or diarrhoea.3,4
The preferred route of nutrition is always to use the
gut, and use parenteral nutrition as a last resort. Enteral nutrition is the safest, simplest, most cost effective
and most physiological route.
Clinical assessment of the body condition, weight of
the patient, muscle condition score, quality of the hair
coat and mental status can guide the clinician in the
nutritional assessment.3,4,6,10
Used in cats with partial anorexia. Commonly
used drugs include diazepam, cyproheptadine
and mirtazapine. Diazepam should be avoided in
cats with liver disease because of its potential hepatic side effects.
In many canine diseases nil per os for the first 24 – 72
hours was recommended in the past. However, studies in general hospital populations of critically ill small
animals have shown that nutritional supplementation,
even in moderation and providing close to RER, was
positively associated with discharge from hospital.2,6
The exact timing of initiation of early enteral nut