Optimizing nutrition in surgical patients and the elderly for strengthened recovery
Surgery is a significant physiologic challenge, particularly in an ageing population with several comorbid conditions. In Singapore, 15–30% of patients admitted to hospital for surgery were found to be malnourished.1 Malnutrition is a precursor for progressive loss of muscle mass and a strong predictor of adverse perioperative outcomes. Nutrition screening plays an important role in the prevention and reversal of malnutrition and low muscle mass, which are likely to positively impact patient outcomes and healthcare costs.
Prevalence of surgical malnutrition
Almost 30–50% of hospitalized adults worldwide are malnourished upon admission, and the rate could further worsen with prolonged hospital stay.2 About 65% of patients undergoing gastrointestinal (GI) surgery are malnourished, and these patients have a higher mortality rate compared with well-nourished patients (23% vs 4%).3 Likewise, complications in GI surgery is almost 5-fold higher in patients who are malnourished than those who are not.3 Malnutrition is the only modifiable risk factor for mortality in surgery. This risk can be effectively predicted based on albumin level, at a cut-off level of <3.5 g/dL.4
Enhanced Recovery After Surgery
Enhanced Recovery After Surgery (ERAS) is a multifactorial programme consisting of interventions at preadmission, preoperative, intraoperative, and postoperative stages, with nutrition as the central pillar.5 Studies have shown that pre- and postoperative nutrition is mismanaged for most patients, with evidence showing that only one in five hospitals in the US has formal nutrition screening processes.6 Additionally, only one out of five patients receive any preoperative nutrition intervention,7-8 despite evidence showing that every USD 1 spent on nutrition therapy in hospitalized patients saves USD 52 on hospital costs.
The Perioperative Quality Initiative (POQI) workgroup has provided key recommendations for perioperative nutrition care, called POQI Nutrition Six, within the ERAS pathway, summarized as follows:8 (1) preoperative and postoperative nutrition screening is essential; (2) protein is more important than calories; (3) stop feeding late preoperatively and restart early postoperatively; (4) consider oral nutrition supplements (ONSs) for all; (5) oral before enteral before parenteral; and (6) nutrition management is a team game.
The ERAS programme is currently utilized by Duke University Preoperative Enhancement Team (POET) nutrition clinic. This programme is one of the referral clinics for patients scheduled for surgery at Duke University Hospital (Figure 1).8 Patients are referred to the POET nutrition clinic via phone-based assessment tool, the Perioperative Nutrition Screen (PONS), comprising the following questions (Table 1):8
The transition from outpatient to inpatient setting is managed using a unique multidisciplinary model and consult service which conduct follow-up.8
Muscle break down and the role of protein
Critical illness is a major cause of muscle glycogen content depletion leading to a pronounced risk of sarcopenia.9 Sarcopenia is associated with early death after surgery and increased risk of infection.10 The recommended assessment can be done via ultrasound imaging to measure leg muscle layer thickness and can assist with nutritional risk prediction preoperatively.8,11
Reaching an overall protein intake goal (>1.2 g/kg daily) is more important than total calorie intake during the preoperative period to prevent sarcopenia.8 Furthermore, patients screened at nutritional risk prior to a major surgery are recommended to receive preoperative ONS for at least 7 days and possibly for 4 weeks or more.8 This may be achieved with either immunonutrition or high-protein ONS given 2-3 times a day, at a minimum dose of 18 g protein.8 Postoperatively, a high-protein diet (via diet/ONS) should be initiated on the day of surgery.8
Optimal nutritional support pre- and postoperatively has been shown to reduce the risk of infections while compliance with ERAS significantly reduces 5-year mortality after surgery.12-14 Remarkably, oral intake on postoperative day 1 is an independent predictor of survival.14 High-protein consumption over the first three postoperative days is associated with shorter hospital length of stay (LOS) compared with low-protein consumption.15 At this point, ONS plays an important role in delivering the required nutrition and additional protein as patients recover from surgery. Studies show that ONS reduces hospital mortality, complications, and LOS, and is a cost-effective intervention.7,16
The addition of β-hydroxy- β-methylbutyrate (HMB) to ONS has been found to further improve muscle mass during recovery.17-18 Accelerated muscle mass loss occurs in inactive hospitalized patients, especially with ageing.19 This muscle loss was attenuated by HMB supplementation at 92% compared with the control group in elderly patients on prolonged bed rest.20 Additionally, the NOURISH study showed that high-protein ONS with HMB significantly increased survival (Figure 2) and reduced mortality at 90 days post-hospital discharge compared with placebo.21 Study shows that the use of high-protein ONS with HMB is a very cost-effective intervention available to improve health outcomes and compares favourably to other well-accepted healthcare interventions, including warfarin for atrial fibrillation, dialysis for kidney injury, and influenza vaccinations.22
Perioperative nutrition must be improved and this can be done by following the POQI Nutrition Six recommendations, as well as by initiating a simple evidence-based by algorithm for nutrition care in the pre- and postoperative settings. Finally, the use of high-protein ONS with HMB in all patients undergoing surgery is essential as this has been proven to attenuate muscle loss due to ageing and illness, support recovery, confer survival benefit, and reduce hospital readmission rates in malnourished patients.
The prevalence of malnutrition in patients at admission is worrying.23 Another cause for concern is that many patients with normal nutrition status experience a decline during hospitalization, while weight and muscle loss during the hospital stay increased the risk of readmissions.25 Recent Singapore data showed that 27.6% of community-dwelling older adults were at risk of malnutrition,26 as were 33% of inpatients at the time of admission27 and 28% of ICU admissions.28
Prolonged metabolic stress without the provision of adequate energy and protein can lead to impaired organ systems.29 Depending on the severity of hypermetabolic catabolism, critically ill patients can lose up to a kilogram of lean body mass daily. This loss of muscle mass has serious implications; a 10% loss of lean body mass has been associated with increased risk of infection. Further loss can result in increased muscle weakness, pneumonia, and the inability to heal. Ultimately, a muscle loss of 40% increases the risk of death.17
The GLIM guidelines for diagnosing malnutrition
The new Global Leadership Initiative on Malnutrition (GLIM) criteria for the diagnosis of malnutrition is an initiative that supports classification of malnutrition into four aetiologic-related diagnosis categories.30 The initiative was developed by an international consortium, and thus helps standardize definitions for detection and interventions. To diagnose malnutrition, at least one phenotypic criterion (non-volitional weight loss, low BMI, and reduced muscle mass) and one aetiologic criterion (reduced food intake or assimilation, and disease burden/inflammation) should be present.31
Early detection of malnutrition and importance of rapid nutritional intervention
Even though the effects of malnutrition can sometimes be reversed after complications occur, it is easier and more effective when malnutrition is anticipated, and preventive action is taken before clinical evidence of malnutrition occurs.
Patients with metabolic stress have a higher nutritional requirement, especially protein, than those without.31 If a patient with metabolic stress is not given adequate nutrition therapy, the body will use its protein stores to supply energy requirements.31 This will cause a delay in wound healing and compromise immune function, thus increasing overall morbidity, mortality, hospital LOS, and costs.
Enteral or oral feeding must be administered early to attenuate the effects of malnutrition on patient outcomes.32 Common objections to early nutrition provision, including haemodynamic instability, high gastric residual volume, no bowel sounds, GI anastomosis, and diarrhoea can be suitably managed and are not reasons to delay enteral or oral feeding. Early recognition of malnutrition and the provision of ONS is applicable to all patients, both with surgical and medical diagnoses. This is critical as greater dietary protein intake can lessen the muscle loss that occurs during illness, as it reduces protein breakdown in the body.31
A nutrition-focused programme to improve patient outcomes, reduce cost
The ADVOCATE study aimed to assess a nutrition-focused quality improvement programme (QIP) on hospital readmission and LOS.32 The malnutrition screening tool (MST) was used to evaluate weight loss and appetite, and quantify patients’ malnutrition risk level.32 Patients with an MST score of ≥2 who received ONS on their next meal tray had reduced 30-day readmission rate and LOS from baseline, and significant cost savings.32-33 In a post hoc analysis, surgical patients had a substantial decline in 30-day readmission rates and shortened LOS by >2 days with QIP (Figure 3).34 Further analysis following patient discharge showed that significant hospitalization risk reductions were observed for all patients regardless of admission source (Figure 4).35
Disease-related malnutrition occurs rapidly in hospitalized patients and carries the risk of sarcopenia, which results in increased episodes of hospital readmission and LOS. The early provision of ONS is an evidence-based intervention that is able to reverse or prevent the effects of malnutrition, thereby leading to improved patient outcomes and cost savings.