American Association for the Surgery of Trauma/American College of Surgeons Committee on Trauma clinical protocol for nutrition support in adult trauma

ABSTRACT:

The provision of nutrition in adult trauma patients requires a detailed and personalized approach to achieve optimal patient outcomes. Initial assessment for malnutrition is required in all patients, as the hypermetabolic state of acute trauma may exacerbate malnutrition risk during the acute phase. Initial assessment in ICU patients includes determination of nutrition risk (high vs. low) using the modified NUTRIC or NRS scores and evaluation for malnutrition. In critically ill trauma patients, indirect calorimetry is most accurate for determination of calorie/protein requirements. Early enteral nutrition is recommended when resuscitation is complete. Continuous gastric feeds are recommended, with postpyloric jejunal feeding for patients at high risk of aspiration. In patients with enteral feeding intolerance and ileus, prokinetic agents should be implemented first, followed by postpyloric feeding tube if persistent feeding intolerance. Parenteral nutrition should be initiated if enteral nutrition is contraindicated (intestinal obstruction, severe ileus, high-output fistula, ischemia), and in patients who cannot achieve goal enteral nutrition. In patients with shock requiring vasopressors, an individualized approach should evaluate the risks and benefits of early enteral nutrition versus the potential risk of nonocclusive mesenteric ischemia. Critically ill geriatric, obese, and cirrhotic trauma patients warrant specialized nutrition care. Immunonutrition, glutamine, and probiotics/prebiotics are not currently recommended for trauma or burn patients.

Nutrition support is an essential component of comprehensive trauma care to achieve optimal patient outcomes. Nutrition assessment should be performed in all trauma patients to screen for malnutrition and in critically ill patients to assess nutrition risk. Trauma patients with low injury severity, and without malnutrition or critical illness, who can tolerate oral nutrition may not need additional nutrition support. Other trauma patients (critically ill, malnourished, high-injury severity, geriatric, significant comorbidities) require careful nutritional risk assessment to determine optimal nutrition goals. This clinical protocol and algorithm reviews current evidence for the provision of nutrition support to adult trauma patients during the acute hospital admission.

PROTOCOL RATIONALE AND GOALS

The goals of this clinical protocol and algorithm (Fig. 1) are to ensure that adult trauma patients (1) have nutrition risks and needs assessment early during hospitalization, in particular to identify malnutrition, and (2) are treated with evidence-based strategies for nutrition support during hospitalization. Nutrition support for pediatric trauma patients is not included.

Figure 1.

Algorithm for nutritional support in adult trauma.

A workgroup with members from AAST Patient Assessment Committee and the ACS-COT conducted a literature review to identify studies related to nutrition in adult trauma patients. Workgroup members reviewed the studies and developed consensus recommendations; where no literature consensus was available, expert consensus was obtained. This clinical protocol has been reviewed and approved by the AAST Patient Assessment Committee and the ACS-COT Performance Improvement and Patient Safety (PIPS) leadership. The final clinical protocol was reviewed and approved by the AAST Board of Managers and the ACS-COT Executive Committee.

This clinical protocol and evidence-based algorithm are based on best available evidence from national and international guidelines (Table 1) and expert consensus of workgroup members. However, treatment decisions should be individualized and do not exclude other treatment strategies as being within the standard of care. Ultimately, the responsibility for treatment decisions rests with the bedside physician.

TABLE 1.

National and International Guidelines

Organization	Guideline	References
American Society for Parenteral and Enteral Nutrition (ASPEN)1	Guidelines for the provision of nutrition support therapy in the adult critically ill patient: The American Society for Parenteral and Enteral Nutrition	Compher C, Bingham AL, McCall M, et al. JPEN J Parenter Enteral Nutr. 2022 Jan;46(1):12-41. doi: 10.1002/jpen.2267. Erratum in: JPEN J Parenter Enteral Nutr. 2022 Aug;46(6):1458-1459. doi: 10.1002/jpen.2419. PMID: 34784064.
Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (ASPEN)2	Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.)	McClave SA, Taylor BE, Martindale RG, et al; Society of Critical Care Medicine; American Society for Parenteral and Enteral Nutrition. JPEN J Parenter Enteral Nutr. 2016 Feb;40(2):159-211. doi: 10.1177/0148607115621863. Erratum in: JPEN J Parenter Enteral Nutr. 2016 Nov;40(8):1200. doi: 10.1177/0148607116670155. PMID: 26773077.
American Association for the Surgery of Trauma (AAST)3	Nutritional support for the trauma and emergency general surgery patient: what you need to know	Hartwell JL, Evans DC, Martin MJ. J Trauma Acute Care Surg. 2024 Jun 1;96(6):855-864. doi: 10.1097/TA.0000000000004283. Epub 2024 Feb 27. PMID: 38409684.
Western Trauma Association (WTA)4	Nutrition therapy in the critically injured adult patient: a Western Trauma Association critical decisions algorithm.	Hartwell JL, Peck KA, Ley EJ, et al. J Trauma Acute Care Surg. 2021 Nov 1;91(5):909-915. doi: 10.1097/TA.0000000000003326. PMID: 34162798.
European Society for Clinical Nutrition and Metabolism (ESPEN)5	ESPEN guideline on clinical nutrition in the intensive care unit	Singer P, Blaser AR, Berger MM, et al. ESPEN practical and partially revised guideline: Clinical nutrition in the intensive care unit. Clin Nutr. 2023 Sep;42(9):1671-1689. doi: 10.1016/j.clnu.2023.07.011. PMID: 37517372.
Society of Critical Care Medicine (SCCM) and American Society of Health-System Pharmacists (ASHP)6	Society of Critical Care Medicine and American Society of Health-System Pharmacists Guideline for the Prevention of Stress-Related Gastrointestinal Bleeding in Critically Ill Adults	MacLaren R, Dionne JC, Granholm A, et al. Crit Care Med. 2024 Aug 1;52(8):e421-e430. doi: 10.1097/CCM.0000000000006330. PMID: 39007578.
Eastern Association for the Surgery of Trauma (EAST)7	Nutritional Support in Trauma Patients (Update in Process)	Jacobs DG, Jacobs DO, Kudsk KA, et al; the EAST Practice Management Guidelines Work Group. J Trauma 2004 September;57(3):660-679.
National Institute for Health and Care Excellence (NICE)8	NICE Clinical Guideline: Nutrition support for adults: Oral nutrition support, enteral tube feeding and parenteral nutrition.	Clinical guideline Published: 22 February 2006 Last updated: 4 August 2017 www.nice.org.uk/guidance/cg32
Chinese Society of Critical Care Medicine9	Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China	Guan X, Chen D, Xu Y. J Intensive Med. 2024 Feb 2;4(2):137-159. doi: 10.1016/j.jointm.2023.12.002. PMID: 38681796; PMCID: PMC11043647.

EVIDENCE BASE: BRIEF SUMMARY

Assessment for Malnutrition

Adult malnutrition is an underrecognized problem and its incidence and prevalence have been difficult to determine.^10–12 Malnutrition is underdiagnosed in over 50% of surgical patients with possible pre-existing sarcopenia and weakness. In TBI patients, severe malnutrition risk at admission was present in over 60% of patients.¹³ Decades after the Joint Commission mandated that nutrition screening occur on admission, guidelines have outlined an approach to the assessment of malnutrition.¹⁴ The Academy of Nutrition and Dietetics (AND) recommended malnutrition screening for all adults in all clinical settings.¹⁵ In 2020, the diagnosis of malnutrition was standardized by the Global Leadership Initiative on Malnutrition (GLIM) with a combination of phenotypic and etiological criteria^16,17 and recommended a 3-step evaluation for malnutrition:

1. Patients must be identified by a validated screening tool.

2. Malnutrition requires at least one phenotypical criterion and one etiological criterion.

3. Malnutrition severity is based on threshold levels of the phenotypic criteria (Fig. 2).

Figure 2.

Global leadership initiative on malnutrition (GLIM) criteria for malnutrition diagnosis. From: Cederholm T, Jensen GL, Correia MITD, et al. GLIM criteria for the diagnosis of malnutrition—a consensus report from the global clinical nutrition community. Clin. Nutr. 2019, 38, 1–9.

At risk patients should have an early consultation with a nutrition support team for an evidence-based nutrition assessment, which has been shown to improve patient outcomes.¹⁸

Assessment of Nutritional Status and Nutrition Risk in ICU Patients

The first step in determining optimal nutrition support in adult trauma ICU patients is assessment of their nutritional status and nutrition risk. Of the many screening and assessment tools, only the modified NUTRIC (mNUTRIC, without IL-6) and NRS-2002 scores (Supplemental Digital Content, Table 1, Supplemental Digital Content 1, https://links.lww.com/TA/F685, 2, Supplemental Digital Content 1, https://links.lww.com/TA/F685) determine both nutrition status and disease severity and are recommended by the SCCM/ASPEN and ESPEN guidelines.^19–22 ICU patients with high nutrition risk are most likely to benefit from early aggressive nutrition support, defined as mNUTRIC score ≥ 5. No survival benefit to nutrition support was identified in ICU patients with low nutrition risk (mNUTRIC score 0–5).²³ Serum protein markers (albumin, prealbumin, transferrin) should not be used to assess nutrition risk or determine the adequacy of nutrition support in adult trauma patients, as they reflect inflammation and resuscitation status.²⁴

Low BMI alone is rarely used to assess malnutrition in North America given the prevalence of obesity. There is no consensus on how to define or measure reduced muscle mass, particularly in trauma. Measurement by absorptiometry, bioelectrical impedance, ultrasound, or anthropometric measures of calf/arm muscle may be impractical in the trauma patient. While CT is increasingly used to assess skeletal muscle mass and has been validated in various disease settings, its use in trauma is limited due to the practical challenges in obtaining imaging, operational complexity, and variability in protocols.^25–27

Critically Ill Versus General Care Trauma Patient

For general care trauma patients, an oral diet with enteral supplements as needed based on calorie/protein requirements is recommended. Critically ill patients with ICU LOS >48 hours should be considered at risk for malnutrition. Oral diets are also recommended in ICU patients, and if not possible, then early EN is initiated. EN is delayed in patients with shock and intestinal hypoperfusion or contraindications (bleeding, severe ileus, high-output fistula (>500 cc/24 h), obstruction, etc). In ICU patients who do not tolerate full-dose EN, supplemental parenteral nutrition (PN) is considered in an individualized approach (see PN below).²⁸

Enteral Nutrition (EN)

The SCCM/ASPEN joint guideline recommends delivering at least 80% of daily prescribed EN therapy to critically ill patients. Despite this, adequate early EN support is frequently not achieved, in part related to cessation of EN for procedures/surgery required for treatment of injuries and postinjury complications. Successful methods to promote adequate EN include (1) use of algorithms to reduce fasting times and optimize periprocedural nutrition (Fig. 3), (2) use of volume-based EN protocol instead of hourly rate, and (3) increased use of postpyloric and jejunal feeding tubes to avoid gastric ileus issues.^29,30 A 2023 meta-analysis of 16 studies (n=2,896) reported that volume-based feeding protocols significantly improved calorie and protein delivery in critically ill patients with no additional risk.³¹ The topic of endoscopic and surgical enteral access for nutrition support is beyond the scope of this clinical protocol.^32,33

Figure 3.

Periprocedural algorithm to reduce interruption of enteral nutrition.

Parenteral Nutrition (PN)

PN should be delayed in ICU patients who are not at high nutrition risk and do not have malnutrition. Early initiation of PN to supplement insufficient or contraindicated EN was associated with prolonged ICU stay versus withholding supplemental PN until one week after ICU admission in two large RCTs (EPaNIC, n=4,640, and PEPaNIC, n=1,440).^34,35 The prospective 2-year follow-up of the EPaNIC study confirmed that withholding PN until 1 week after ICU admission had no impact on 2-year mortality and physical functioning in any nutritional risk subgroup, confirming long-term safety with this practice.³⁶ In patients with malnutrition, earlier initiation of PN may be indicated, and should be personalized.

The ESPEN guidelines recommend consider PN initiation if >50% of the energy requirement has not been met by EN for >7 days.³⁷ The ASPEN guidelines recommend that PN should be initiated within 3 to 5 days for patients who are at nutritional risk and unlikely to achieve desired oral intake or with insufficient EN (<60% of energy requirement).³⁸ A multicenter RCT compared early (day 3) versus late (day 8) supplemental PN in major abdominal surgery patients with high nutritional risk and poor EN tolerance. Early PN was associated with significantly decreased nosocomial infections with no difference in secondary outcomes (adverse events, LOS, cost) but was limited related to no control of SSI prevention practices, ERAS protocols, and high rates of infectious complications.³⁹

Calorie Recommendations in ICU Patients

Energy expenditure (EE) in trauma ICU patients can fluctuate daily, complicated by injury and disease severity, nutritional status, and treatments making caloric need predictions challenging. ICU nutrition guidelines recommend indirect calorimetry (IC) to determine caloric needs, and guidance by serial IC measurements are associated with improved clinical outcomes.^40,41 Predictive formulas to calculate EE are inaccurate (39–62% agreement with IC) and can result in underfeeding/overfeeding.⁴² Some ICs are inaccurate, challenging to calibrate, and limited by patient need for supplemental oxygen use. Newer easier ICs are available allowing for expanded use to optimize nutritional support prescription.⁴³ Current national guidelines recommend hypocaloric nutrition with adequate protein in the early acute phase of critical illness (hypercatabolic state, first week) in ICU patients, with a personalized approach to increase to adequate calorie/protein repletion in the later stages of critical illness.⁴⁴ This approach is safe in ICU trauma patients with either beneficial or neutral impact on ICU outcomes; however, there is no evidence that it improves outcomes in trauma ICU patients, and additional randomized trials are needed.⁴⁵

Protein Recommendations in ICU Patients

National and international nutrition guidelines recommend 1.3 to 2 g/kg/day protein for hospitalized patients requiring EN or PN. Higher protein delivery, compared with lower, did not improve clinical outcomes in critically ill patients in multiple systematic reviews and was associated with increased mortality rates in patients with acute kidney injury in some studies.^46–48 Two recent large studies have provided additional information.

The EFFORT-Protein international trial (largest to date) randomized 1301 nutritionally high-risk adult ICU patients requiring mechanical ventilation to high protein (≥2.2 g/kg/day) with usual dose protein (≤1.2 g/kg/day) started within 96 h of ICU admission. Both study cohorts did not receive the recommended protein dose (high dose 1.6 g/kg/day versus usual dose 0.9 g/kg/day). No difference in 60-day mortality was identified in the entire cohort, but the subgroups of AKI and higher organ failure scores at baseline had higher mortality with high-protein dose.⁴⁹ In a post-hoc analysis of ICU patients with AKI, the harmful effects of high protein were not noted in those who received renal replacement therapy. High protein treatment did not improve outcomes in ICU patients with malnutrition (43.8% of patients) or with obesity (32.7% of patients).^50,51

The PRECISe trial randomized 935 critically ill patients requiring invasive mechanical ventilation to isocaloric enteral feeds with either standard (1.3 g/kg/day; 1.3 kcal/mL, 0.06 g protein/mL) or high (2.0 g/kg/day; 1.3 kcal/mL, 0.10 g protein/mL) protein. No mortality difference was identified, but high enteral protein supplementation was associated with worse health-related quality of life and did not improve functional outcomes in ICU patients. No adverse effect of high protein was found with AKI or organ failure. Renal replacement therapy was used in more high-protein patients (PRECISe 17% vs. EFFORT Protein 5%). The PRECISe trial also had higher mean caloric intake (19 vs. 13.2 kcal/kg/day).^52,53

Trauma patients comprised only 10% of the study cohort in both of these large trials. A randomized single-center trial in trauma (85%) and surgical ICU patients (n=500) reported that increased protein supplementation did not improve outcomes and was associated with increased complications.⁵⁴ We need additional research to clarify specific protein recommendations in ICU trauma patients, with additional assessment of traumatic injury healing, impact of physical therapy, and maintenance of muscle mass.

ENTERAL NUTRITION AND SHOCK STATES, VASOPRESSOR ADMINISTRATION

Initiation of EN in the setting of circulatory shock is controversial.^55,56 These patients are already at risk for development of nonocclusive mesenteric ischemia (NOMI) potentially leading to intestinal necrosis due to splanchnic vasoconstriction with an associated mortality rate of 50% to 75%.^57,58 The current SCCM/ASPEN Guidelines recommend delaying EN until the patient is “fully resuscitated” and hemodynamically stable. The 2023 ESPEN Guidelines highlight current limitations in the evidence supporting the use of EN in shock states and recommend that EN should be delayed “if shock is uncontrolled and hemodynamic and tissue perfusion goals are not reached” as no randomized interventional studies have been published to date.⁵

Two recent multicenter studies (one randomized,⁵⁹ one retrospective)⁶⁰ evaluated this patient population after resuscitation to assess early (<48 h) versus late (> 48 h) EN initiation and outcomes. Both studies reported decreased ICU LOS in the early EN group, but without mortality benefit. Both studies reported increased gastrointestinal complications (ie, abdominal distension, ileus, emesis/aspiration, diarrhea, intestinal ischemia, and intestinal necrosis) in the early EN group, and one patient in each study developed mesenteric ischemia. The NUTRIVAD study was a multicenter prospective observational study to evaluate EN started 34 hours after ICU admission in mechanically ventilated ICU patients requiring vasoactive drugs and/or mechanical circulatory support (n=200, 26 trauma patients (13%) included).⁶¹ Gastrointestinal complications occurred in 77% of patients and one patient developed NOMI requiring total abdominal colectomy and ileostomy. Mortality was high at 24% and this study had no control group.

The NUTRIREA-2 trial randomized more than 4,000 mechanically ventilated patients in circulatory shock to receive early full-dose EN or PN during the first ICU week. No differences in 28-day mortality were noted, but early full-dose EN, compared with PN, had significantly more clinically relevant bowel ischemia (2% vs. <1%, p=0.007) and feeding intolerance (vomiting and diarrhea).⁶²

The NUTRIREA-3 trial randomized adult ICU patients (n=3036) requiring mechanical ventilation and vasopressors for shock to early EN (within 24 h of intubation) with either low (6 kcal/kg/day, 0.2–0.4 g/kg/day protein) versus standard (25 kcal/kg/day and 1.0–1.3 g/kg/day protein) calorie and protein targets during the first ICU week. The low group had significantly decreased bowel ischemia (HR 0.50, 0.26–0.95; p=0·030), vomiting, diarrhea, and liver dysfunction, with no difference in mortality.

These studies provide a high level of evidence that patients benefit from restricted enteral calorie/protein intake during the resuscitative phase, and that delayed EN is best in shock patients.^63,64 Although many studies have reported that gastrointestinal complications occur in the setting of “high” vasopressor rates, there is no published consensus definition at present.^65–67 Also, some vasopressors have more negative effects on splanchnic vasoconstriction and risk for NOMI than others. Furthermore, some patients may have cardiovascular dysfunction with low ejection fraction in addition to vasopressor need and may be at higher risk for NOMI with initiation of EN. A recent comprehensive review of all published data regarding initiation of EN in patients with shock requiring vasopressors recommended a personalized approach and concluded that the risks/benefits of EN should be weighed carefully for each patient.^68,69

FEEDING INTOLERANCE IN ENTERAL NUTRITION

Feeding intolerance can occur with EN, most commonly manifested by high gastric residual volume (GRV), abdominal distention, nausea, vomiting, and diarrhea. Although no standard definition for feeding intolerance exists, these symptoms may result in inadequate EN support since EN is frequently stopped when these symptoms occur. A systematic review of 26 observational cohort studies (n=25,189) found that 40% of medical/surgical ICU patients had feeding intolerance, which was associated with feeding inadequacy and with increased all-cause ICU mortality (RR 1.99, 95% CI: 1.69 to 2.35).⁷⁰ Although some nutrition guidelines recommend not monitoring GRV based on studies in nontrauma ICU patients, definitive trauma trials are lacking, and a personalized approach may be optimal. Studies in trauma patients confirm feeding intolerance with high GRV (> 500 mL or >250 mL with vomiting) was strongly associated with higher mortality.^71,72 A systematic review in burn patients recommended use of 500 mL GRV thresholds to help balance nutritional needs and aspiration risk.⁷³ Higher EN calorie delivery is associated with increased rates of gastric dysmotility and high GRVs.⁷⁴ Prokinetic agents (metoclopramide, erythromycin) are commonly used to increase gastric emptying when feeding intolerance is related to high GRV, nausea, and vomiting. Combination therapy (IV erythromycin and metoclopramide) was more effective than erythromycin alone in ICU patients with feeding intolerance.⁷⁵ There is moderate quality evidence that prokinetic agents reduce feeding intolerance in ICU patients compared with placebo/no intervention.^76,77 EN-related diarrhea is also very common, confirmed in over 60% of ICU patients, related to multifactorial etiologies, and an algorithmic approach for treatment of EN-related diarrhea is optimal (Fig. 4).⁷⁸

Figure 4.

Algorithm for diarrhea evaluation and treatment with enteral nutrition. Recommended dosing of antimotility medications for diarrhea treatment: • Loperamide: 4 mg once, then 2 mg after each loose stool. Maximum dose: 16 mg per day; may schedule up to 4 mg q6h if effective. • Diphenoxylate/atropine: Start at 1 tab (5 mL liquid, 2.5 mg diphenoxylate) 4 times per day. Maximum dose: 2 tabs (10 mL liquid, 5 mg diphenoxylate) 4 times per day. Maximum of 20 mg diphenoxylate per day. • Banatrol TF: (banana flakes with liquid modular fiber). One (60 mL) packet =5 g soluble fiber (45 calories) 70 mg (∼2 mEq) potassium per packet. Recommended first dose: 1 packet BID (10 gm soluble fiber). Maximum recommended dose: 2 packet BID (20 gm soluble fiber).

Refeeding Syndrome (RS)

Refeeding syndrome is a complication of nutritional support, particularly in the critically ill, with metabolic/electrolyte derangements occurring with provision of EN/PN after a period of decreased caloric intake.⁷⁹ In 2020, ASPEN developed a new clinical definition for RS (criteria below) and proposed consensus recommendations.⁸⁰

• A decrease in any 1, 2, or 3 of serum phosphorus, potassium, and/or magnesium levels by 10% to 20% (mild RS), 20% to 30% (moderate RS), or >30% and/or organ dysfunction resulting from a decrease in any of these and/or due to thiamine deficiency (severe RS).

• And occurring within 5 days of reinitiating or substantially increasing energy provision.

Early identification of patients at moderate/significant risk for RS (Fig. 5) is critical with prompt treatment initiation.⁸¹

Figure 5.

ASPEN consensus criteria for identifying adult patients at risk for refeeding syndrome.

CRITICALLY ILL TRAUMA PATIENT SUBPOPULATIONS

Critically Ill Geriatric Trauma Patients

Age is a significant risk factor for increased mortality in trauma patients.⁸² Compared with younger adults, geriatric trauma patients are more susceptible to complications and adverse outcomes with similar injury severity.⁸³ Malnutrition is common in this patient population. Thus, it is essential to assess the nutritional status of critically ill older adults so care can be optimized early. The Geriatric Nutritional Risk Index (GNRI), developed by modifying the Nutritional Risk Index, is a validated scoring system used to predict malnutrition-related complications related in both trauma and nontrauma patients. Major GNRI risk (GNRI score of <82) is associated with significantly increased mortality and infectious complications in geriatric trauma patients.^84,85 A secondary analysis of the AAST Trauma Frailty Multi-Institutional Trial (n=1321) confirmed that 22% of geriatric trauma patients had poor nutritional status (mild 13%, moderate 6%, severe 3%) measured by the simplified GNRI, and was associated with increased sepsis, pneumonia, hospital, and 3-month mortality.⁸⁶

The assessment of the geriatric patient at risk for malnutrition is complicated, as being overweight may, in fact, decrease the relative risk of increased mortality with age.^87,88 Baseline sarcopenia is also common in geriatric trauma patients, and trauma is associated with further significant loss of skeletal muscle mass due to acquired sarcopenia. A recent study reported sarcopenia increased from 36% at baseline to 60% at 6 months after severe trauma in older patients.⁸⁹ In a study of critically ill medical/surgical older adults, each fasting day increased the mortality risk by 16.7%.⁹⁰ With the concomitant hypercatabolic state of critical illness and the high prevalence of sarcopenia, early administration of nutrition support in geriatric trauma patients is vital. However, few studies inform optimal nutritional management of sarcopenia patients.⁹¹ A recent study in geriatric trauma patients found that predictive equations significantly underpredict energy expenditure and metabolic demands compared with IC and perform worse in lower BMI patients.⁹² Use of IC is recommended to achieve optimal nutrition support in this high-risk group.

Critically Ill Obese Trauma Patients

Determining the nutritional needs of obese ICU patients is challenging because BMI does not assess sarcopenia. Calculating nutritional needs is commonly performed based on actual, adjusted, or ideal body weight, and Society guidelines have differing recommendations.⁹³ Upon ICU admission, nutritional status in overweight/obese critically ill adults can be assessed with the subjective global assessment (SGA) tool and a nutrition focused physical exam (NFPE).⁹⁴ A systematic review (24 studies) found poor agreement between energy targets using predictive equations recommended by ASPEN/ESPEN clinical guidelines and measured REE by IC, with most predictive equations underestimating energy needs.⁹⁵

Guidelines for caloric and protein goals in obese patients are based on low-grade evidence. The ESPEN guidelines recommend that IC be used to determine nutritional needs or ideal body weight with predictive equations if IC is unavailable. Hypocaloric feeding with increased protein (2–2.5 g/kg/day) using ideal body weight is advised. The ASPEN Obesity Guidelines suggest using actual body weight with the Penn State University 2010 predictive equation if IC is unavailable.⁹⁶ And recommend hypocaloric (50–70% of estimated energy requirements) high-protein feeding (low-quality evidence) in patients without renal or liver dysfunction. The ASPEN/SCCM guidelines agree that IC is preferred and, if unavailable, a simple weight-based equation can be used. They recommend EN initiation within 24 to 48 hours of admission providing 11–14 kcal/kg actual body weight for BMI of 30 to 50 kg/m² and 22 to 25 kcal/kg ideal body weight for BMI >50 kg/m².

Critically Ill Trauma Patients With Cirrhosis

Critically ill patients with cirrhosis frequently have pre-existing malnutrition. As many as 80% of patients with decompensated cirrhosis may already be suffering from severe malnutrition with an increased REE.⁹⁷ Furthermore, cirrhosis alters the gut microbiome, impairs motility, is associated with trace mineral deficiency, significant protein loss, sodium retention, and increased total body water content. Vitamin and mineral deficiencies are common, especially in those with significant alcohol intake. It is essential to ensure that nutrition assessment and nutrition goals are prioritized.^98,99

The Royal Free Hospital-Nutrition Prioritizing Tool (RFH-NPT) predicts malnutrition risk better in cirrhosis patients compared with the NRS-2002 score and other scores.^100,101 The RFH-NPT is more specific for patients with liver disease and includes weight loss, dietary intake, presence of alcoholic hepatitis. Risk for malnutrition is assumed if BMI is <18.5 kg/m² or Child-Pugh Class C in cirrhosis. Using GLIM criteria, 38% of outpatients with liver cirrhosis met criteria for malnutrition.¹⁰² As recommended in all adult trauma patients, EN should be initiated as soon as possible in cirrhotic trauma patients with standard polymeric formulation and no protein restriction. Branch chain amino acid (BCAA) enteral formulas are not recommended routinely but can be considered in hepatic encephalopathy.¹⁰³ Supplementation with thiamine, folate, and multivitamins, especially in those with a history of alcohol abuse and evidence of severe malnutrition is important.¹⁰⁴ In patients with severe hepatic encephalopathy or hyperammonemia nutritional protein support may be held for 24–48 hours until the blood ammonia levels decrease or hepatic encephalopathy improves.^105,106

IMMUNONUTRITION

Immunonutrition includes immunomodulating agents such as fish oils (omega-3 fatty acids), glutamine, arginine, nucleotides, RNA, and antioxidants. The use of these agents and immune-enhanced formulas is controversial. Studies are difficult to interpret due to heterogeneity of patient populations and formulations and limited information regarding the individual component supplementation.^107–113 Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been studied in various populations. A small single-center retrospective study in TBI patients with ICU LOS ≥ 2 weeks compared immunonutrition with n-3 PUFA versus standard polymeric formula found no mortality difference, although multivariate regression analysis associated immunonutrition with reduced hospital LOS.¹¹⁴ A small RCT in multisystem trauma patients (n=32) reported increased markers of immune function (IgG, IgM, IgA, total lymphocyte count, CD4 cells, and ratio of CD4/CD8 cells) in the immune-enhanced formula group versus standard formula on days 7 and 14.¹¹⁵ A meta-analysis of 7 RCTs (n=322) of nutritional support with n-3 PUFA in burn patients found no difference in mortality, infectious complications, ventilator days or LOS.¹¹⁶ Similarly, a Cochrane review of immunonutrition in burn patients (16 trials, n=678) with glutamine as the most common supplement (7 of 16 studies) showed no impact on infectious complications.¹¹⁷

Glutamine

Previous guidelines had recommended glutamine administration in trauma and burn patients, based on perceived benefits on the metabolic/stress response to severe injury. However, recent studies do not confirm benefit. The RE-ENERGIZE trial¹¹⁸ was a double-blind placebo-controlled RCT (n=1,209 burn patients, mean burn size 33% TBSA) which compared enteral glutamine (0.5 g/kg/d) versus placebo and found no difference in mortality or time to discharge alive from hospital. A systematic review of glutamine supplementation in severe adult burn patients reported no difference in mortality or infectious complications.¹¹⁹ Similarly, supplemental glutamine had no impact on mortality or infectious complications in adult trauma and critically ill patients.¹²⁰ Glutamine use is not recommended.

PREBIOTICS AND PROBIOTICS

Prebiotics are compounds that stimulate growth of beneficial microorganisms in the gut. No studies with prebiotics in trauma patients were found in the literature search. Probiotics are live nonpathogenic microorganisms administered to improve microbial diversity in the gut.^121,122 A RCT with enteral probiotic supplementation in multiple injured patients for one week found no differences in prognostic scores, inflammatory markers, or outcomes compared with no supplementation.¹²³ A small (n=40) double-blind placebo-controlled RCT in severe TBI patients reported that administration of a 7-strain probiotic led to significant reduction in inflammatory markers (TNF, IL1) and Th17 cells and significant increase in IL-10 and T-regulator cells, but no impact on SOFA or APACHE scores.¹²⁴ The use of prebiotics or probiotics is not recommended in trauma.

Limitations

There are limited high-quality studies in trauma patients. Due to the heterogeneous patient populations and limited subgroup analysis in most studies, data regarding nutritional support in the trauma population is lacking. No formal evaluation of the level of evidence or strength of recommendations was performed for this clinical protocol based on these limitations.

CONCLUSION

Nutrition support is a critical component of comprehensive trauma care to achieve optimal patient outcomes. Nutrition assessment should be performed in all trauma patients to screen for malnutrition and in critically ill patients to assess nutrition risk. Some trauma patients (low injury severity, no malnutrition, no critical illness) who can tolerate oral nutrition may not need additional nutrition support. Other trauma patients (critically ill, malnourished, high-injury severity, geriatric, significant comorbidities) require careful nutrition risk assessment to determine optimal nutrition goals. This clinical protocol and algorithm reviews current evidence regarding recommendations for the essential provision of nutrition support to adult trauma patients during the acute hospital admission.

Supplementary Material

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