The Power of Nutrition

Dear Readers: Increasing evidence supports the importance of nutrition in wound care. Proper nutrition provides the essential amino acid building blocks of cells, extracellular matrix and granulation tissue proteins, essential fatty acids and carbohydrates to fuel cell migration and proliferation, the function and production of molecules required to repair or regenerate all aspects of damaged tissue, and the water that permits function of the metabolic pathways involved. Two recent studies summarized in this edition of Evidence Corner suggest that nutritional effects on the immune system may improve clinical healing outcomes and reduce complications. Laura Bolton, PhD, FAPWCA Adjunct Associate Professor Department of Surgery, UMDNJ WOUNDS Editorial Advisory Board Member and Department Editor

Immunonutrition for High-risk Surgical Patients

  Reference: Marik PE, Zaloga GP. Immunonutrition in high-risk surgical patients: a systematic review and analysis of the literature. J Parenter Enteral Nutr. 2010;34(4):378–386.   Rationale: Immunomodulating diets (IMDs) improve immune function and modulate inflammation. Effects remain to be proven on clinical outcomes for high-risk patients undergoing elective surgery.   Objective: Perform a meta-analysis of controlled clinical trials to evaluate IMD impact on clinical outcomes of high-risk patients undergoing major elective surgery.   Methods: The authors reviewed literature including prospective, controlled clinical studies that compared clinical outcomes of high-risk patients undergoing elective major surgery randomized to receive either an IMD or a control enteral diet. Studies were stratified by type and timing of IMD initiation. Data on study design, IMD used, and patient numbers and characteristics were abstracted. Meta-analyses analyzed incidence of mortality, new infections, wound complications, and length of hospital stay.   Results: Twenty-one relevant studies with a total of 1918 qualifying patients were analyzed. Only IMDs containing both arginine and fish oil significantly reduced the risk of acquired postoperative infections, wound complications, and length of hospital stay. These effects were independent of IMD initiation timing. Mortality was 1% for both IMD and control patients.   Authors’ Conclusions: Enteral IMD with both arginine and fish oil should be considered for all high-risk patients undergoing major surgery.

Nutrition and Pressure Ulcer Healing

  Reference: Cereda E, Gini A, Pedrolli C, Vanotti A. Disease-specific, versus standard, nutritional support for the treatment of pressure ulcers in institutionalized older adults: a randomized controlled trial. J Am Geriatr Soc. 2009;57(8):1395–1402.   Rationale: Nutritional support interventions have reported mixed effects on pressure ulcer healing. Randomized controlled clinical trials (RCT) are needed to clarify efficacy.   Objective: Conduct a RCT to compare pressure ulcer healing effects of a disease-specific nutritional supplement with those of a standard dietary approach.   Methods: A randomized controlled study provided a standard diet of 30 kcal/kg/day to 28 older patients with Stage II to IV pressure ulcers in four long-term care facilities in Como, Italy. Of these, 15 patients received standard enteral formula with 16% of calories from protein. The remaining 13 patients were randomized to receive the same standard diet enriched with 20% of the total calories as protein supplemented with arginine, zinc, and vitamin C administered as 400 mL daily of a specialized oral supplement. The primary outcome was ulcer healing after 12 weeks defined as percent or mm2 of pressure ulcer area reduction or PUSH Scale score improvement.   Results: Baseline age, gender, type of feeding, oral intake, and pressure ulcer severity were similar for both intervention and control groups. After 12 weeks, both control and specialized diet groups significantly improved in pressure ulcer healing (P < 0.001). Patients receiving the specialized diet improved more in 8-week mm2 (P < 0.05) and percent (P < 0.02) area reduction and 12-week PUSH scores (P < 0.05) than control patients.   Authors’ Conclusions: The rate of pressure ulcer healing may be accelerated when a standard diet is supplemented with an oral or enteral diet rich in protein, arginine, zinc, and vitamin C.

Clinical Perspective

  Adequate nutrition is recognized as an important factor in chronic^1,2 and acute³ wound management, prevention,⁴ and rehabilitation.⁵ The systematic review and meta-analysis by Marik and colleagues adds strong evidence supporting efficacy of preoperative enteral nutritional interventions in reducing incidence of post-operative hospital-acquired infections or wound complications and length of hospital stay for high-risk patients undergoing major elective surgery. These effects were consistent only if the enteral supplements contained both fish oil and the amino acid arginine. The small RCT by Cereda et al generates interesting questions for further research. It lays the foundation for a larger prospective RCT to confirm efficacy of the arginine-zinc-vitamin C supplement in healing pressure ulcers and to identify which dietary component(s) produce this effect. In view of the post-operative effects in high-risk elective surgery patients confirmed by Marik et al, one might wonder if adding effective levels of fish oil to the arginine-zinc-vitamin C supplement may further improve pressure ulcer healing outcomes. Prior research has shown that zinc supplementation improves healing only in zinc-deficient subjects. Future research may determine if the supplement effects on pressure ulcer prevention, healing, or complications are related to patient nutritional deficiencies. Both studies offer food for thought. Future research is needed to identify and optimize the effective nutritional intervention(s) to improve chronic and acute wound outcomes. What other prevention, healing, or related outcomes are affected by nutrition? Which factors identify a patient who is likely to respond to these nutritional interventions? Further research will reveal the answers to these questions.

References

1. Coutts P, Barton P, Burrows C, et al. Assessment and Management of Venous Leg Ulcers Guideline Supplement. Toronto, ON: Registered Nurses Association of Ontario, Nursing Best Practice Guidelines Program; 2007. 2. Ratliff CR. WOCN’s evidence-based pressure ulcer guideline. Adv Skin Wound Care. 2005;18(4):204–208. 3. Pearl ML, Frandina M, Mahler L, Valea FA, DiSilvestro PA, Chalas E. A randomized controlled trial of a regular diet as the first meal in gynecologic oncology patients undergoing intra-abdominal surgery. Obstet Gynecol. 2002;100(2):230–234. 4. Lyder CH, Shannon R, Empleo-Frazier O, McGeHee D, White C. A comprehensive program to prevent pressure ulcers in long-term care: exploring costs and outcomes. Ostomy Wound Manage. 2002;48(4):52–62. 5. Wells JL, Seabrook JA, Stolee P, Borrie MJ, Knoefel F. State of the art in geriatric rehabilitation. Part II: clinical challenges. Arch Phys Med Rehabil. 2003:84(6):898–903.