Nutrition in hospitalized patients is often overlooked in the early hours of illness. With blood work to run and radiographs to take, diarrhea to clean up and blood pressures to measure we forget that our patient has not eaten in two days in the hospital, and maybe not for two days before admitting to the hospital. The body relies on nutrition to function, and more importantly to heal, so why do we ignore nutrition until days later?
The GI tract is one of the first lines of immune defense in the body. Without nutrition, the cells lining the intestines begin to die off leaving breaks in the armor. The patient becomes more susceptible to bacterial infection which leads to inflammation and increased vessel permeability. With a systemically ill patient this becomes one more front to fight and can contribute to morbidity and mortality. In both sick and healthy patients the link between immune function and nutrition is important to stress to pet owners.
When a sick animal stops eating, their body responds differently than an otherwise healthy animal that suddenly does not have access to food. In that otherwise healthy animal, the animal begins to break down fat stores to be used for energy. In the diseased patient, the body begins breaking down lean muscle for energy. The loss of lean muscle mass can lead to immune system dysfunction, increased time for wound healing, and weakness. All of these are important functions for general healing and getting out of the hospital. Early nutritional intervention can contribute to better healing. So what are barriers to nutrition in the hospital environment? Some of these barriers we as hospital workers can control, others we cannot, but it is our job to remove as many barriers as possible to encourage oral nutrition.
- Trauma – some patients will not eat because their face or body has sustained trauma that makes it impossible to eat. Jaw fractures, esophageal trauma, penetrating foreign body, mechanical obstruction causing tissue death, ingestion of a corrosive substance; all of these issues can take days or weeks to heal and certainly need nutritional intervention.
- Disease – many disease processes result in nausea and the patient unwilling to eat. Pain can be a giant hurdle to eating and must be taken into consideration. Mechanical obstruction and/or ileus can cause discomfort and vomiting.
- Hypoperfusion – during shock, the gut is often hypoperfused and can lead to ileus, ulceration, vomiting and diarrhea. A patient experiencing hypoperfusion for any period of time may have difficulty returning to normal eating habits right away.
- Fear – we all know that the hospital is not the most comfortable environment for our patients. The fear they experience may prevent them from settling down enough to eat.
- Owner resistance – some owners do not want to expend the emotional or financial commitment to have their pet in the hospital receiving nutrition. It can fall to the technician to further explain the options and answer basic questions about feeding tubes.
The decision to intervene with nutritional support is made by the veterinarian and client, and occurs when it is known the patient does not have a GI obstruction or other physical impairment to eating. The role of the technician should be to keep nutrition top of mind, work with the patient to remove as many barriers as possible to encourage eating, and understand how to administer the medications prescribed. Before jumping to interventions like feeding tubes, there are various medications that can and should be used in an attempt to encourage eating. First, look at pain. Managing pain is not only important to nutrition, but to the overall ability of your patient to heal efficiently. Sometimes the only outward sign of pain that can be identified is reluctance to eat. When deciding to intervene, be sure pain is adequately managed. That being said, opioids can cause ileus and be the cause of an animal not eating. Motility disorders are difficult to treat. Low dose erythromycin (0.5mg-1.0mg/kg q8-12h PO or IV) and ranitidine (2mg/kg q8h IV or PO) may improve gastric emptying but the true efficacy of this is questionable. Metoclopramide, when used as a CRI (1-2mg/kg/day IV), has the best potential to improve motility and therefore stimulate appetite.
Anti-emetics will reduce nausea and vomiting and should be considered in patients with these clinical signs. Ondansetron (0.1-0.2mg/kg q6-8hr IV) and dolansetron (1.0mg/kg q24h IV) suppresses vomiting receptors in the vagus nerve and in the brain and can help with nausea. Maropitant (1mg/kg q24h SC) works against neurotransmitters to suppress vomiting. Stress ulceration is a common occurence in humans with critical illness and the possibility exists with dogs. Gastric acid reducing medications such as famotidine (canine 0.1-0.2mg/kg q12h IV/IM/SC/PO; feline 0.2mg/kg q24h IM/SC/PO) and omeprazole (canine 20mg/dog q24h PO; pantoprazole 0.7mg/kg q24h IV) can aid in patients with GI ulceration. When the use of these drugs still does not result in a patient willing to take in nutrition, or trauma/illness will not allow for voluntary intake of nutrition, intervention becomes necessary. The decision to intervene with nutrition should be made early in the patient’s hospital stay, but it is important to ensure the patient is ready to receive nutrition. The animal needs to be cardiovascularly stable prior to the introduction of enteral nutrition. Shock results in decreased perfusion to the gut which in turn impairs digestion and motility. Patients should be fluid resuscitated and the underlying cause of shock determined and treated. Patients who are vomiting are not candidates for almost all types of feeding tubes. Vomiting can change the placement of many tubes and vomiting will render enteral nutrition a waste of time and resources. In the face of intractable vomiting, IV nutrition should be considered.
Feeding the gut is vital. Without food in the gut, the top layers of epithelial cells, as well as the mivrovilli, will begin to die off. Enterocytes need food in order to maintain the tight junctions between each cell, thus keeping gut bacteria where it belongs. Without food, permeability increases, bacterial translocation may occur, and inflammation occurs. Providing IV nutrition will provide energy to organs and cells, but will not maintain the gut tissues like enteral feeding will. Providing enteral nutrition is more cost effective, less technically challenging, and better overall for the health of the intestines. If caloric demands cannot be met with enteral feeding along, a combination of IV and enteral nutrition can occur.
Once the decision is made to provide nutrition, each patient will need their energy requirements calculated and the correct amount of food ordered. Many patients will be started on a liquid diet, but some canned preparations can be blenderized and fed through larger tubes. A resting energy rate (RER) is calculated for each patient, regardless of disease process. Even through a critically ill animal has higher energy requirements than a healthy animal it is possible to provide too much nutrition and cause vomiting and/or diarrhea. If the patient is tolerating enteral feeding well their caloric intake should still take 48-72 hours to increase to full RER. When calculating RER it is important to use the patient’s current weight and not adjust for ideal weight. Use either of the following formulas:
RER = 70*(weight in kg)0.75 OR RER= (30*weight in kg) + 70
In many cases feeding is started at 1/4 to 1/3 RER and increased slowly over 48 hours. The patient should be monitored closely for signs of nausea and vomiting. Vomiting can easily cause tube dislodgement and in these circumstances feeding should be discontinued immediately and only restarted when the patient has gone a period of time (normally 8-12 hours) with no vomiting. Most patients with feeding tubes will begin eating when they are ready, and as they begin to take in a significant amount of nutritional orally the amount fed through the tube can be decreased and eventually discontinued.
Types of feeding tubes:
- Nasoesophageal/Nasogastric Tube: Allow for trickle feeding of gut and can provide full RER via liquid diet (often CRI). Used for anorexic patients with functional GI tract. Nasogastric tube has added benefit of allowing suction and decompression of the stomach. Simple to place, requires sedation +/- brief anesthesia. For in-hospital nutrition, removed before patient returns home.
- Esophagostomy Tube: Allow for nutritional bypass of mouth in trauma, larger tube size allows for canned preparation to be fed in bolus feedings. Surgical placement necessary but owners can be taught to feed via esophagostomy tube and take the pet home.
- Percutaneous Endoscopically placed Gastrostomy Tube (PEG): Allow for nutritional bypass of mouth and esophagus in trauma/disease, tube placed directly into stomach. Larger bore tube allows for canned diet feeding in bolus feedings. Surgical placement necessary but owners can be taught to feed via PEG tube and take the pet home.
- Jejunostomy Tube: Allow for nutritional bypass of mouth, esophagus and stomach, for severe pancretitis/pancreatectomy cases. Surgical placement of tube directly into jejunum. Liquid diet only, and only in hospital setting.
Technicians play an important role in providing nutrition for patients. As patient advocates, technicians are monitoring for patient well-being and will bring anorexia to the veterinarian’s attention. The placement of some feeding tubes is performed by the technician; and the use, care, and client training with feeding tubes falls to the technician team. Nutrition is vital to healing and health in all of our patients, and should be evaluated early and often in illness and health.
Brunetto, Marcio A., Marcia O. S. Gomes, Marco R. Andre, Eliana Teshima, Karina N. V. Gonçalves, Gener T. Pereira, Antonio S. Ferraudo, and Aulus C. Carciofi. "Effects of Nutritional Support on Hospital Outcome in Dogs and Cats." Journal of Veterinary Emergency and Critical Care 20.2 (2010): 224-31. Print.
Yu, Melissa K., Lisa M. Freeman, Cailin R. Heinze, Valerie J. Parker, and Deborah E. Linder. "Comparison of Complication Rates in Dogs with Nasoesophageal versus Nasogastric Feeding Tubes." Journal of Veterinary Emergency and Critical Care23.3 (2013): 300-04. Print.
Campbell, Jennifer A., L. Ari Jutkowitz, Kari A. Santoro, Joe G. Hauptman, Melissa L. Holahan, and Andrew J. Brown. "Continuous versus Intermittent Delivery of Nutrition via Nasoenteric Feeding Tubes in Hospitalized Canine and Feline Patients: 91 Patients (2002-2007)." Journal of Veterinary Emergency and Critical Care 20.2 (2010): 232-36. Print.
Chan, Daniel L., DVM, DACVECC, DACVN, FHEA, MRCVS. "Dealing With Gastrointestinal Dysfunction in the ICU." 19th IVECCS. San Diego, CA.
VanEnkevort, Bruce A., DVM, DACVS. Surgical Feeding Tube Placement. 15th IVECCS, Chicago, IL
Papich, Mark G. Saunders Handbook of Veterinary Drugs. 2nd ed. Philadelphia, PA: Elsevier/Saunders, 2011. Print.