Nutrition in Challenging Conditions

Continuing Professional Education Session


Nutrition in patients with CRRT

(Pierre Singer)


AKI – metabolic modifications, hypercatabolism, hyperglycaemia

Nutrients and solutes levels affected by haemodialysis/haemofiltration

IMG_0432 IMG_0434

Equations to calculate energy expenditure (EE) can be misleading in CRRT, likely to result in overfeeding – measure EE by indirect calorimetry after 6 hours stabilisation


Pts use more fat than carbohydrates, therefore give 50% fat + 50% carbs


Amino acids lost through convection and ultrafiltration: 8g/day, total loss including catabolism: 10-15g/day, therefore give at least 1.3g/kg/day protein and more to compensate for losses


Loss of micronutrients in effluent: Selenium, Copper, Zinc –replace with trace element solutions



Hypophosphataemia in AKI treated with haemodialysis is associated with adverse events


Nutrition of obese patients

(Mette Berger)


BMI poor indicator of body composition / obesity, doesn’t account for muscle loss in ageing and disease, and does not detect sarcopenia (measured on cross sectional CT imaging at Lumbar L3 level)



Obesity associated with increased all-cause mortality in hospitalised pts (increased prevalence of hypertension, Type 2 DM, hypercholesterolaemia)


High rates of central obesity and sarcopenia in CKD irrespective of RRT


Obesity and trauma:

  • Relative block on lipolysis and fat oxidation
  • Shift to preferential use of proteins and carbohydrates
  • Resultant catabolism


Glucose handling in obesity:

  • Relative insulin resistance and risk of Type 2 DM
  • Sepsis/trauma induces post-receptor insulin resistance
  • Significant risk of hyperglycaemia (conventional feeds use carbohydrates as predominant energy source)


Obesity can co-occur with malnutrition – MDT approach to handle various aspects of obesity


How much to feed obese pts?

  • Penn State Equations: 80% validity in predicting resting metabolic rate in critically ill pts at extremes of BMI

(Prediction of resting metabolic rate in critically ill patients at the extremes of body mass index.)


Simple guide:

  • Assess nutritional need and develop plan within 48hrs of ICU admission (pt usually has little reserves)
  • Will need Indirect Calorimetry or Penn State Equations for more accurate calculation of energy expenditure
  • Feeding should not be hypocaloric, but rather Aim for Iso-caloric for lean mass
  • Ideal body weight used to calculate protein needs (2-2.5 g/kg)
  • Careful attention to micronutrients, B12, Cu, Fe to avoid anaemia / neurological problems
  • Convert to Enteral feeding as soon as pt is stabilised



Nutrition during non-invasive ventilation

(Steffen Weber-Carstens)


Reasons NOT to feed enterally during NIV:

  • Potential need for intubation
  • NGT presence may cause air leakage, compromising effectiveness of NIV
  • Gastric distension associated diaphragmatic splinting
  • Removal of mask to consume oral diet may cause deterioration



In this group of pts, TPN is in fact preferred to EN – no increase in mortality / gastrointestinal infection rate with TPN compared to EN; EN associated with significantly more GI infections

Enteral versus parenteral early nutrition in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2).


Nutrition in necrotising pancreatitis

(Valentin Fuhrmann)


Severe acute pancreatitis

  • shock, respiratory failure, AKI, delirium, abdominal compartment syndrome
  • mortality 20%
  • Early enteral nutrition (EN) important in the multimodal therapy



Mild- oral feed once pain / vomiting resolved

Severe- Early EN – ESPEN 2018; Parenteral nutrition only when EN route not available / not tolerated / not meeting energy requirements (ACG 2013)


NG tube feeding safe and well-tolerated compared to NJ feeding

Nasogastric or nasojejunal feeding in predicted severe acute pancreatitis: a meta-analysis


Feeding intolerance is common in acute pancreatitis (nausea, vomiting, ileus, diarrhoea)

Early versus on-demand nasoenteric tube feeding in acute pancreatitis.


Managing feeding intolerance:

  • Start EN early to avoid extended ileus
  • Re-assess GI function early
  • Slow start, do not aim for full energy needs
  • Prokinetics
  • Post-pyloric feeding is an option if prokinetics not helping
  • Diagnose and manage of intraabdominal hypertension
  • Consider parenteral route




ESICM guidelines:  DELAY enteral feeding in cases of

  • Uncontrolled shock
  • Uncontrolled hypoxia / hypercapnoea / acidosis
  • Abdominal compartment syndrome
  • Gastric aspirates > 500mls / 6hrs




Nutrition in elderly frail patients

(Jean-Charles Preiser)



Nutritional management in frailty:

  • Acute phase: refeeding risk
  • Recovery phase: Need adequate calories, high protein intake, exercise, selected pharmaconutrients


ESPEN Recommendations for refeeding hypophosphataemia

  • Measure electrolytes 2-3x/day, supplement if needed
  • Restrict energy supply for 48hrs then gradually increase


Positive energy balance is associated with accelerated muscle atrophy (Positive energy balance is associated with accelerated muscle atrophy and increased erythrocyte glutathione turnover during 5 wk of bed rest)


Burden of critical illness in frail pts lasts for long period after d/c from ICU and hospital

  • huge task of rebuilding
  • Vit D deficiency associated with muscle loss (type 2 myocytes), supplementation increases muscle protein synthesis in non-critically ill
  • Selected amino acids, in particular leucine, can stimulate muscle protein synthesis
  • Combination of increased protein intake, amino acid supplementation and exercise



Nutrition in malnourished patients

(Michael Hiesmayr)


Risk factors for malnutrition include:

  • Unintentional weight loss >5% in 1 month
  • Starvation >7days
  • Prolonged hypocaloric feeding / chronic swallowing difficulties
  • Idiosyncratic diets (qualitative malnutrition)
  • Nutrient losses / reduced absorption e.g. GI condition, chronic pancreatitis, chronic antacid use (by binding minerals), chronic high-dose diuretics, post bariatric surgery


Malnourished pts do not always look thin (e.g. bariatric surgery); low BMI does not mean malnourishment (e.g. endurance sports)


Those who tend to eat less in hospital are either the elderly or pts <39 yrs of age: ? related to unusual situation of being hospitalised at this age / history of chronic illness



  • BMI – fluctuates with fluid resuscitation
  • Muscle mass – visualisation by CT / Ultrasound (degree of subjectivity)
  • Muscle function – MRC grading of strength, Dynamometer
  • Bioimpedance


Muscle layer thickness is dynamic and fluid-sensitive

  • up to 15% apparent increase in muscle mass after 8-hr surgical procedure
  • reflects lean tissue, but also fluid, impaired venous return and inflammation





Nutrition risk assessment:


Estimate body weight if unknown

Investigate nutrition history

  • history from pt / family
  • If malnourished, start slow feed and increase progressively
  • Prophylactic thiamine
  • Supplement K+, Mg++, PO4- (measure)

Observe pt for GI tolerance, cardio/pulmonary tolerance


Sensible take home messages:

  • Due to loss of autonomy, ICU pts are often dependent on nutrition care
  • Always consider malnutrition once the pt has been on ICU >7 days even if body size appears fine
  • Look at the patient, not just the numbers – muscle bulk, hands, overall appearance
  • NO reason not to feed early once condition stabilised
  • If the pt is ‘eating independently’ on ICU, always monitor intake to avoid false reassurances of adequate nutrition
  • Aim to retrain pt to eat while on ICU + swallowing test before discharge to the ward, where there is less direct nursing care and risk of further malnutrition