Parenteral Nutrition
Parenteral nutrition refers to nutrients delivered to the
patient in a manner other than through the gastrointestinal (GI)
tract. This type of nutrition is used in the most critical patients
which may have one or more of the following symptoms:
- Intestinal obstruction or ileus
- Inadequate digestive or absorptive capacity
- Uncontrollable vomiting (this is particularly life threatening
to a diabetic animal)
- Inability to tolerate food for any reason (eg., head trauma,
burns to mouth/face/esophagus)
- High risk of aspiration because the patient is unconscious or
has a neurologic problem
- Need for complete GI tract rest due to digestive disease,
healing time needed for GI tract lesions or surgical repairs, acute
pancreatitis or hepatitis
Parenteral nutrition can be delivered to the patient by
intravenous, intramuscular, subcutaneous, intraosseous or
intraperitoneal routes, but the preferred method in veterinary
medicine for the majority of patients requiring this type of
nutrition is via a jugular intravenous catheter. The risk of
infection is the greatest worry with this type of catheter and
aseptic (sterile) technique must be used at all times. This type of
support is generally given for a period of no more than 14 days, at
which point the patient has hopefully begun to recover from the
symptoms that caused the need for the catheter.
The solution fed through the catheter is a carefully balanced
solution of dextrose, lipids, amino acids, electrolytes (which may
be supplemented if needed by a peripheral catheter) and B-vitamins.
The formulation is tailored to the patient's daily needs for
calories, fluids and electrolytes, protein and whether the patient
will do better getting the majority of its energy requirement from
dextrose (sugar) or lipids (fats). Complete blood counts (CBC) and
blood chemistrics are monitored at least daily to measure the
patient's progress on the chosen solution and adjustments are made
as needed.
This type of nutritional support can only be administered within
the hospital due to the need to use sterile technique in handling
the catheter and solution. Also, patients requiring this support
are generally very critical and need the supervision of 24-hour
intensive care support. This kind of care is given at Texas
A&M's Intensive Care Unit where many critical patients have
received parenteral nutritional support as part of their hospital
care.
References:
Lon D. Lewis, Mark L. Morris, Jr. and Michael S. Hand.
Intravenous feeding. Small Animal Clinical Nutrition III. p5-35,
1994.
Michael S. Hand, Craig D. Thatcher, Rebecca L. Remillard and
Philip Roudebush. Parenteral Assisted Feeding. Small Animal
Clinical Nutrition 4th Edition. p375, 2000.
J.M. Wills and K.W. Simpson. Parenteral Nutrition. The Waltham
Book of Clinical Nutrition of the Dog and Cat. p49, 1994.