CHAPTER
Nutrition for the Oral and
3 Maxillofacial Surgery Patient
Pamela Hughes
| Jon P. Bradrick
| Charles J. Yowler
OUTLINE
Fasting- and Starvation-Induced Malnutrition Physiology Mechanics of Enteral Feeding
Trauma-, Stress-, and Sepsis-Induced Malnutrition Physiology Enteral Formula Delivery
Substrate Depletion and Requirements Enteral Diets
Protein Requirements Polymeric Enteral Formulas
Amino Acids Oligomeric Enteral Formulas
Electrolyte Requirements Monomeric Enteral Formulas
Glucose and Insulin Osmolarity
Assessment Tools for Diagnosis of Nutritional Failure Energy Sources in Enteral Formulas
Clinical Assessment Complications of Enteral Nutritional Therapy
Laboratory Assessment Parenteral Nutritional Therapy
Nutritional Support Methods for Patients with Functioning Peripheral Parenteral Nutrition and Total Parenteral
Gastrointestinal Systems Nutrition
Indications for the Use of Nutritional Therapy Initiating Nutritional Support in the Critically Ill Patient
Oral Methods of Nutritional Therapy Intermaxillary Fixation
Nonoral Methods of Nutritional Therapy
Nasogastric Feeding Tubes
Transcutaneous Enteral Feeding Tubes
A
mong the many functions the oral cavity provides, FASTING- AND STARVATION-INDUCED
one of the most important is the entry of nutrients MALNUTRITION PHYSIOLOGY
into the gastrointestinal (GI) tract. The ability of
a patient to ingest a normal diet by mouth can be altered A healthy 75-kg man normally stores 200 to 300 g of
by many things, including neoplasia, infection, congeni- carbohydrate, equal to 800 to 1200 kcal (4 kcal/g),
tal deformities, and injury. Oral and maxillofacial mostly as glycogen.3 Fat is normally 15% to 30% (11 to
surgeons provide form- and function-altering surgical 22 kg) and protein 14% to 20% (10 to 15 kg) of body
procedures to correct these problems, and these proce- weight. The average total caloric reservoir is therefore
dures themselves may limit function of the oral cavity. approximately 200,000 kcal, of which 75% is fat. In the
Most patients are well nourished before their visit. complete absence of nutritional intake, an otherwise
However, those patients with chronic illness, alcoholism, healthy person could catabolize 1 to 2 g/kg of protein
or anorexia and those who are older, institutionalized, or and 2 to 3 g/kg of fat/day. Theoretically, this caloric
homeless may be in various stages of malnutrition. The reserve could sustain life for 3 to 5 months. Realistically,
mortality and morbidity of these malnourished patients death would occur after burning about 140,000 kcal
is clearly higher than well-nourished patients who have (75% body fat and 50% body protein).4
sustained maxillofacial or multisystem trauma, or are Starvation involves a cascade of substitution of energy
undergoing the same operation. Evaluation and correc- substrates as the body attempts to conserve energy
tion of malnutrition are time-consuming and not dra- resources and cellular functions. With the onset of star-
matic, yet its correct recognition and application can vation, glycogenolysis provides most of the necessary
reduce postoperative complications. This chapter will blood glucose. The available glycogen stores are rapidly
compare the physiology of slow compensated starvation depleted, and amino acids become the prime source of
to the all-consuming hypermetabolism of the critically carbon for hepatic gluconeogenesis. The amino acid
injured trauma victim. As is true in many clinical areas, sources are muscle, connective tissue, and visceral pro-
the literature can be contradictory and can offer oppos- teins. As starvation continues, the rate of gluconeogen-
ing opinions. Some believe that early enteral feeding in esis diminishes, coincident with a decrease in metabolic
trauma patients results in decreased morbidity and com- rate and increase in ketone use as fuel by the central
plications.1 Others conclude that nutritional support is nervous system. The early loss of body mass is slowed
currently overused, improperly used, and has failed to and accompanied by a decrease in urinary nitrogen
show an improvement in clinical outcome.2 excretion. In a healthy patient, nitrogen intake equals
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