Nutrition in Surgical Patients

Ronald Merrell, MD

Chairman of Surgery

Virginia Commonwealth University

What?

• Carbohydrate

• Lipid

• Protein

• Trace elements

• Vitamins

Who?

• Malnourished (>10% lean body mass)

• Incapable of eating (>10 days)

Why?

• Risks of malnutrition including infection, poor healing and higher mortality

• Malnutrition is exacerbated by physiological stress

When?

• Preoperative?

• Early?

• Late?

• ---after initial resuscitation following injury or surgery

How?

• Parenteral

• Enteral

• Total

• Partial

Issues

• Metabolic response to injury

• Cytokines, inflammation, hormones

• Biology of substrates

• Enteral vs. Parenteral

“Ashen faces, a thready pulse and cold clammy extremities…”

The Ebb Phase

Cuthbertson, Quart. J. Med.25:233,1932

The Ebb Phase

• Hypometabolic• Hypothermic• Hypoinsulinemic• Hypoperfusion

• Hypercortisolism• Hyperglucagonemia• Hyperglycemia• Hypercatecholemia

“The patient warms up,cardiac output increases and the surgical

team relaxes…”

The Flow Phase

Cuthbertson. Lancet 1:233, 1942

The Flow Phase

• Hypermetabolic• Hyperthermic• Catabolic

• Hyperinsulinism• Hypercortisolism• Hyperglucagonemia• High cardiac output

Nutritional Assessment

• Body weight

• Body mass index

• creatinine height index

• Serum proteins:albumin, prealbumin, transferrin

• Immune competence: lymphocytes, DH

• Nitrogen balance

Caloric Requirement

• Formula

• Indirect calorimetry

• PRN for nitrogen balance

• Approximation

Nutritional Requirements

• 25 cal/kg/day

• carbohydrate ~70%

• Lipid 15-30%

• Protein 1.5-2.0g/kg/day. Not for calories

• Additional 50% to 100% for stress as in ICU patients

Nutritional Goals

• Nitrogen balance

• Preserve or restore visceral protein

• Reduce morbidity

• Reduce mortality

• Reduce hospital stay

Early Enteral Feeding: a meta-analysis

• Eight prospective randomized trials with trauma and high risk surgical patients(118 enteral, 112 parenteral)

• Septic complications:enteral 18%, parenteral 35%

• Moore. Ann. Surg. 216:172,1992

Parenteral requirements

• Dilution in right heart return because of hyperosmolarity…….Central Venous Line

• Delivery of simple carbohydrate (20%glucose)

• Lipid emulsion

• Amino acids

Enteral Requirements

• Delivery into the GI tract by tube with minimum risk of aspiration or patient effort

• Delivery of nutrients with minimal need for digestion

• Control of rate to prevent osmotic diarrhea

Advantages of enteral nutrition

• Easier

• GI bacterial translocation

• Cheaper

• Fewer specific complications

Nutrients with specific putative contributions

• Branch chain amino acids

• Glutamine

• Arginine

• Nucleotides

• Omega-3 fatty acids

Immune Enhancing Diet

• Arginine, nucleotide, fish oil

• Shorter stay, fewer infections

• Bower Critical Care Medicine. 23:436, 1995

Parenteral Nutrition Immunosuppressive

IF...• Poorly administered

• Hyperglycemia

• No nucleotides

• No arginine

• No taurine

• Excessive fats

Overfeeding with parenteral diets

• Carbohydrate: hyperglycemia, hypercarbia, fatty liver

• Lipids: hypertriglyceridemia, hypoxia, infection

• Protein: azotemia

Conclusions

• Nutrition is a powerful determinate of patient outcome

• The proper provision of nutrition is a component of basic patient care

• Nutrition is a precise and potentially very hazardous form of intervention