Alameda County Medical Center / Highland General Hospital
Trauma Service

 Nutritional Assessment
Background
Significant limitations exist in clinicians’ ability to quantify the degree of malnutrition, identify the degree of metabolic injury and stress, and measure the effectiveness of nutrition in reversing nutrition-related immunological and metabolic abnormalities.  Numerous parameters have been used to classify patients into the states of mild, moderate, and severe malnutrition.  Nutritional assessment begins during the history and physical exam with the calculation of the % of body weight loss. In general, 5% to 10% weight loss over a month or 10% to 20% over 6 months is associated with increased complications.(1)
 
%  body weight loss = [(Usual body weight - current body weight)/ usual body weight] x 100
 
Transport Proteins
Albumin is considered the single best serum marker of malnutrition in an otherwise stable patient (T1/2 = 21days).  Other transport proteins measured are transferrin (T1/2 = 8 days) and pre-albumin (T1/2 = 2-3days).  Serum levels of these transport proteins are influenced by synthesis rates, degradation rates and vascular losses into the interstitium, and losses through the gut or kidney.  Levels drop in inflammation, trauma, sepsis, peritonitis or burns where high levels of IL-6 stimulate acute phase protein production as it inhibits transport protein production. (2)  In protein energy malnutrition, synthesis rate of albumin is reduced and likewise degradation rate and thus, for example, in marasmus you have normal albumin levels until nutritional support is provided and then it drops precipitously.
 
Delayed Cutaneous Hypersensitivity (DH)
This is a known marker for severe malnutrition. 
DH is delayed hypersensitivity reaction to one of three recall antigens(0, nonreactive: 1, <5-mm induration: 2, >5-mm induration)
It is influenced by injury, hepatic and renal failure, infections, edema and steroids.
  
Prognostic Nutritional Index (PNI) (3)
As a predictive tool a combination of all these measurements have been used to qualify the risk for subsequent complication.  The Prognostic Nutritional Index correlates with poor outcome in the following equation:
 
PNI%= 158- 16.6(albumin) – 0.78(TSF) – 0.2(TFN) – 5.8(DH)
 
TSF= Triceps skin fold thickness in mm
TFN= Tranferrin
DH = Delayed hypersensitivity (may be substituted with lymphocyte score)
 
The higher the score the higher the risk of infection.
In acute disease, elevations in acute phase proteins occur with simultaneous reductions in transport proteins, the Prognostic Inflammatory Nutrition index (PINI) (4) appears to correlate with recovery from injury in the following equation:
PINI =  (CRP)(AAG) 
            (PA)(ALB)   
 
where CRP= C-reactive protein,  AAG= alpha 1-acid-glycoprotein, PA= pre-albumin, ALB=albumin
In summary, there is no “gold standard” for determining nutritional status due to the influence of illness and injury on assessment parameter and the difficulty in isolating the individual influences of malnutrition and disease on clinical outcome.
 
Enteral Nutrition 
Both clinical and economic considerations suggest the use of enteral route for feeding whenever possible.  The observation that ileus is often limited to the stomach and colon whereas the small intestine remains a site capable of absorption of nutrients has advanced the clinician’s ability to successfully feed via the GI tract.  Patients undergoing laparotomy for major torso trauma or major intestinal surgery or patients with severe closed head injury develop gastropariesis that prevent early intragastric feeding but nutrition delivered beyond the ligament of Treitz is well tolerated.  This would encourage the surgeon to plan for post-operative enteral feeding by placing a jejunal feeding tube.  Multiple class 1 studies show that in the above group of patients a demonstrable significant reduction in pneumonia and intra-abdominal abscess is noted with early use of small bowel feeding.
  • Moore et al. in 1989 randomized 75 patients with ATI>15 and <40 to either enteral feeding or immediate TPN.  Results showed that infectious complications, primarily pneumonia, were significantly lower in the enteral than TPN group.(5)  
  • In 1992 Kudsk, et al. randomized 96 patients to either early jejunal feeds or TPN; patients in the enteral group sustained significantly fewer pneumonias, intra-abdominal abscesses and line sepsis than parenterally fed patients.(6)
  • Rapp et al. in 1983 randomized 38 patients with blunt or penetrating head injuries within 48hrs into either TPN or intragastric feeding. Mortality increased in the enterally fed patients vs. none in the TPN group, and sepsis was approximately 30% in the intragastric group vs. none in the TPN group. (7)
  • Grahm in 1989 studied 22 patients with blunt or penetrating wounds with GCS < 10 and randomized them to nasojejunal feeding within 36hrs of admission or intragastric feeding after day three with return of GI function. Early jejunal feeding resulted in significantly fewer respiratory bacterial infections.(8)
  • And finally Borzotta in 1994 compared TPN and surgical jejunostomy starting feeds 72 hrs after injury and there was no difference in infectious complications, he noted that diarrhea was more common in the TPN group.(9)
 
Complications of Enteral Feeding
The most common complications of tube feeding include diarrhea, aspiration, vomiting, metabolic abnormalities and tube dislodgement.  Small bowel necrosis and pneumatosis intestinalis have been associated with direct small-bowel feedind.It is speculated that this is caused by inability to increase blood flow to the splanchnic bed when products are into the small intestine and thus it is prudent to delay jejunal feedings until hemodynamic stability is achieved.
 
 
References
1. Blackburn et al. Nutritional and metabolic assessment of the hospitalized patient. J Parenteral Enteral Nutrition 1977;1:11-22.
2. Kudsk et al. Visceral protein response to enteral vs parenteral  nutrition and sepsis in trauma patients  Surgery 1994;116(3):516-523
3. Buzby GP, et al . Prognostic nutritional index in gastrointestinal surgery, Am J Surg 1980:139:160-167
4. Ingenbleek Y, Carpenter YA. A prognostic inflammatory and nutritional index scoring in critically ill patients, Int J Vitam Nutr Res 1984;55:91-101
5. Moore FA, Moore EE, Jones TN, et al . TEN versus TPN following major abdominal trauma- reduced septic morbidity, J Trauma 1989;29:916-923
6. Kudsk KA, et al. Enteral versus parenteral feeding. Effects on septic morbidity after blunt and penetrating abdominal trauma, Ann Surg 1992;215:503-511.
7. Rapp RP, et al. The favorable effect of early parenteral feeding on survival in head injured patients,  J Neurosurg 1983;58:906-911
8. Graham TW, Zadronzy DB, Harrington T. The benefits of early jejunal hyperalimentation in the head-injured patient, Neurosurgery 1989;25:729-735
9. Borzotta AP, et al. Enteral vs parenteral nutrition after severe closed head injury,  J Trauma 1994;37:459-468.
 
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