January 2015 Issue
Optimizing Nutrition Before Surgery
By Densie Webb, PhD, RD
Vol. 17 No. 1 P. 10
RDs can ensure patients are well nourished before procedures to ease recovery, shorten hospital stays, and reduce complications.
It's a little-appreciated fact that up to 50% of patients are malnourished when they're admitted to the hospital, yet according to a Johns Hopkins study, only about 20% of patients receive a nutritional consult.1 Another surprising fact: Malnutrition increases the risk of death after surgery, significantly raises the risk of postoperative complications, and is a chief reason why patients are readmitted to the hospital.2 In addition, hospital stays are longer and health care costs can be more than 60% greater for malnourished patients.3 It affects all ages, but the elderly are especially vulnerable. So why aren't nutrition assessments and pre- and postsurgical nutrition interventions routine in many hospitals?
David Evans, MD, of The Ohio State University, an outspoken advocate for nutrition assessment and support both pre- and postsurgery, offered some insight at the Academy of Nutrition and Dietetics' Food & Nutrition Conference & Expo in October 2014, when he said, "Traditional beliefs still persist among surgeons to delay initiating nutrition support, despite recommendations to the contrary." The recommendations he's referring to, known as "enhanced recovery of patient after surgery," or ERAS, urge preoperative nutrition assessments and counseling; prebiotic/probiotics administration; limiting preoperative fasting to two to three hours, rather than the traditional six to 12 hours; and immediate postoperative fluid and diet initiation, to name a few approaches. Formed in Sweden, the ERAS Society has developed protocols, which include such nutrition guidelines. The third congress of the society is slated to meet in May 2015 in Washington, D.C., to discuss these protocols and determine if they need to be updated.
The Stress of Surgery
Surgery poses a catabolic stress on the body, which triggers inflammation and depletes nutrients; this, in turn, can impair the immune response and increase the risk of postoperative complications, especially infections.4
"Surgery is like a sport," Evans said, "and we have to be the trainers. If you're not well trained, if you're not ready for surgery, you're not going to do well."
Two main approaches to pre- and postoperative nutrition have been studied the most: standard oral nutrition supplements (ONS) and immunonutrition (IN) supplements. ONS, most often in liquid form, provide extra protein and calories to supplement a patient's diet. Available in a wide variety of flavors, ONS products, such as Ensure, Boost, and Resource 2.0, typically are much less expensive and far more palatable than IN, resulting in better patient compliance. Poor palatability, leading to poor patient compliance, defeats the purpose of any nutrition prescription.4 Moreover, a recent literature review found no statistical difference in infections, complications, and length of hospital stay between patients given IN or ONS.4
Findings from studies on ERAS protocols contradict traditional management of postsurgical patients, which typically calls for prolonged fasting before surgery and a clear liquid postsurgery diet. In addition to a shorter length of hospital stay, some of the benefits of ERAS may be earlier return of bowel function, decreased time to mobilization for patients, fewer postoperative complications, ability to tolerate solid foods sooner, and lower readmission within 30 days postsurgery. But ERAS protocols incorporate several components in various combinations, many of them unrelated to nutrition, such as rapid mobilization following surgery, no nasogastric tube, early removal of catheters, and the use of warm IV fluids, making it difficult to specifically identify nutritional support as the deciding factor in a patient's ease of recovery.
IN supplements, such as Impact Advanced Recovery and Nutren Optimum, vary in ingredients and concentrations, and the ideal dosages for the best surgical outcome haven't been defined. Because of the varying formulations (some product preparations differ from country to country from a single manufacturer), the ingredients most responsible for benefiting surgical outcome aren't easily identified.4 Among the ingredients found in these types of supplements are arginine, omega-3s, nucleotides, prebiotics, probiotics, vitamin E, and high-quality protein, and antioxidants often are included. A synergy among the ingredients could play an important role.4 However, the two ingredients that appear to provide the most benefit are the conditionally essential amino acid arginine and omega-3s derived from fish oils. Arginine is essential for the functioning of immune cells and operates as a precursor to proline and polyamines, which are necessary for tissue repair and wound healing.4 Fish oil-derived omega-3s mediate the inflammatory response.4
There's much more research on the effect of ONS products on surgical outcome, and they've been shown in several studies to reduce postsurgical complications.4 Standard ONS products are high in protein, contain vitamins and minerals, and are widely available. Some also contain arginine and omega-3s, but in lesser amounts than IN products.
Hydration, Carbohydrate Loading, and Muscle Strengthening
While six to 12 hours of fasting before surgery currently is the norm, Evans said long periods of fasting can lead to insulin resistance, hyperglycemia, failure to achieve a postsurgery anabolic state, and sometimes, the need for insulin. Rather, he said, carbohydrate loading before surgery may be beneficial for ease of recovery. Carbohydrate-loading protocols are common in other countries, but there are no such protocols in the United States.
Hydration before surgery also is important. Studies show that when patients are well hydrated, they report less pain and nausea after surgery. Despite the fact that prolonged fasting before surgery is the norm, the American Society of Anesthesiologists suggests that patients can consume clear liquids up to two hours before surgery with no increased risk of aspiration.5
Because surgery puts the body in a catabolic state, building lean body mass with increased protein intake and exercise before the procedure may increase the ease of recovery. Again, no specific protocols are in place, but increasing protein intake along with exercise, when possible, should be encouraged.
Who Needs Preoperative Nutrition?
While nearly everyone potentially can benefit from a preoperative nutritional assessment and therapy, not everyone will benefit equally. There's a need to first identify the high- vs low-nutrition risk patients and the surgeries that pose high vs low nutrition risk. Evans said high-risk patients are those who have lost more than 5% of their weight in the last one to three months, have a BMI of less than 18.5, and have a significant reduction in food intake (25% to 75%); take steroids; and have cancer or immunosuppression, whether the result of medication or disease. High-risk surgeries include esophageal, gastric, and some colorectal surgeries. Major orthopedic and neurological surgeries also are high risk, but these patients are less likely to be malnourished going into surgery. Hernia, gallbladder, and outpatient surgeries are relatively safe with little nutrition risk. For severely malnourished patients, Evans recommends total parenteral nutrition before surgery. Two widely accepted tools to determine the nutrition status of surgical patients are the Subjective Global Assessment and Nutrition Risk Screening 2002.6
Preoperative Nutrition of the Future
Evans believes dietitians are poised for a revolution in nutrition therapy for pre- and postsurgical patients, which will include greater adherence to ERAS protocols, carbohydrate loading before surgery, and more acceptance of IN and muscle-strengthening protocols. All of these presurgical nutrition protocols, with the exception of total parenteral nutrition, apply to both well-nourished and mildly malnourished surgical patients and could reduce postsurgical complications and the rate of readmittance to the hospital. What can RDs do to get surgeons and anesthesiologists on board? Evans said, "Bring evidence that will encourage them to buy into these nutrition protocols." And that evidence in the nutrition and medical literature has been building exponentially.
— Densie Webb, PhD, RD, is a freelance writer, editor, and industry consultant based in Austin, Texas.
1. Somanchi M, Tao X, Mullin GE. The facilitated early enteral and dietary management effectiveness trial in hospitalized patients with malnutrition. JPEN J Parenter Enteral Nutr. 2011;35(2):209-216.
2. Kotze V. Perioperative nutrition: What do we know? S Afr J Clin Nutr. 2011;24(3):S19-S22.
3. Gallagher LG. The high cost of poor care: the financial case for prevention in American nursing homes. The National Consumer Voice for Quality Long-Term Care website. http://theconsumervoice.org/uploads/files/issues/The-High-Cost-of-Poor-Care.pdf. Updated April 2011.
4. Hegazi RA, Hustead DS, Evans DC. Preoperative standard oral nutrition supplements vs immunonutrition: results of systematic review and meta-analysis. J Am Coll Surg. 2014;219(5):1078-1087.
5. Hayhurst C, Durieux ME. Enteral hydration prior to surgery: the benefits are clear. Anesth Analg. 2014;118(6):1163-1164.
6. Raslan M, Gonzalez MC, Torrinhas RS, Ravacci GR, Pereira JC, Waitzberg DL. Complementarity of Subjective Global Assessment (SGA) and Nutrition Risk Screening 2002 (NRS 2002) for predicting poor clinical outcomes in hospitalized patients. Clin Nutr. 2011;30(1):49-53.