Is it Possible and Necessary to Is it Possible and Necessary to Estimate Energy Requirements in the Estimate Energy Requirements in the

Critically Ill?Critically Ill?

Pete TurnerPete Turner

Senior Nutritional Support DietitianSenior Nutritional Support Dietitian

Estimating energy requirementsEstimating energy requirements

This could be relatively easy in a healthy This could be relatively easy in a healthy individual…individual…

Formulae to estimate BMR (REE)Formulae to estimate BMR (REE) Schofield/Harris BenedictSchofield/Harris Benedict Activity factors / PARsActivity factors / PARs Is an ITU patient different?Is an ITU patient different?

The ICU PatientThe ICU Patient

The inflammatory response.The inflammatory response.

Similar responses seen in trauma, burns, Similar responses seen in trauma, burns, sepsis and surgery. sepsis and surgery.

Involves local and systemic reactions.Involves local and systemic reactions. Extent of reaction proportional to severity Extent of reaction proportional to severity

of insult.of insult. Excessive response can produce a systemic Excessive response can produce a systemic

response e.g. SIRS and MODS.response e.g. SIRS and MODS.

Inflammatory response.Inflammatory response.

Tissue injury results in release of cytokines.Tissue injury results in release of cytokines. Important cytokines include TNFImportant cytokines include TNFα, IL-1, IL-2, α, IL-1, IL-2,

IL-6, interferon and prostaglandins e.g. E2… IL-6, interferon and prostaglandins e.g. E2… regulate response.regulate response.

Endocrine response includes the release of Endocrine response includes the release of glucocorticoids eg cortisol…. Catabolic… insulin glucocorticoids eg cortisol…. Catabolic… insulin antagonism.antagonism.

?Proteolysis inducing factor (PIF) and intracellular ?Proteolysis inducing factor (PIF) and intracellular catabolic processes in skeletal muscle (Curtis et al catabolic processes in skeletal muscle (Curtis et al 2002, Nutrition 18, 971-977). 2002, Nutrition 18, 971-977).

Effects of inflammatory responseEffects of inflammatory response Catabolism… negative nitrogen balance (up to 20g /day, Catabolism… negative nitrogen balance (up to 20g /day,

Campbell 1999).Campbell 1999). Weight loss, Weight loss, ↓skeletal muscle & contractile proteins – ↓skeletal muscle & contractile proteins –

weakness and fatigue (Curtis et al 2002)weakness and fatigue (Curtis et al 2002) Acute ICU patients can lose 5-10% muscle per week (Griffiths Acute ICU patients can lose 5-10% muscle per week (Griffiths

2003) 2003) Synthesis of acute phase proteins.Synthesis of acute phase proteins. Lipolysis and gluconeogenesis.Lipolysis and gluconeogenesis. Insulin resistance & hyperylcaemiaInsulin resistance & hyperylcaemia HypermetabolismHypermetabolism AnorexiaAnorexia ↑ ↑ vascular permeability and hypoalbuminaemia. vascular permeability and hypoalbuminaemia.

Nutritional Support on ICU.Nutritional Support on ICU.

Can we completely reverse the malnutrition Can we completely reverse the malnutrition caused by the inflammatory response with caused by the inflammatory response with nutritional support?nutritional support?

Nutritional Support on ICUNutritional Support on ICU

It would seem logical to give as much energy and It would seem logical to give as much energy and protein as possible to try to reverse these effects… protein as possible to try to reverse these effects…

But several studies show aggressive nutritional But several studies show aggressive nutritional support does not prevent loss of lean mass support does not prevent loss of lean mass (Frankenfield et al 1997, JPEN, 21(6): 324-9, (Frankenfield et al 1997, JPEN, 21(6): 324-9, Shaw et al 1987, Ann Surg, 209, 63-72.)Shaw et al 1987, Ann Surg, 209, 63-72.)

Streat et al 1987, J. Trauma 27, 262-266. MOF Streat et al 1987, J. Trauma 27, 262-266. MOF patients lost 12.5% body protein despite 10 days patients lost 12.5% body protein despite 10 days of PN giving 2400kcal, 20gN. of PN giving 2400kcal, 20gN.

Energy BalanceEnergy Balance

Achieving energy balance does not prevent Achieving energy balance does not prevent muscle wasting in critically ill.muscle wasting in critically ill.

Shown in 2 studies on mid arm Shown in 2 studies on mid arm circumference on ITUs (Reid et al Clin Nut circumference on ITUs (Reid et al Clin Nut 2004, 23(2) 273-80, Green et al Clin Nut 2004, 23(2) 273-80, Green et al Clin Nut 1995 11(6): 739-461995 11(6): 739-46

Achieving energy balance may be over Achieving energy balance may be over feedingfeeding

So what if we are overfeeding?So what if we are overfeeding?

Studies on outcome - TPNStudies on outcome - TPN

Heyland meta-analyses in the critically ill and Heyland meta-analyses in the critically ill and surgical patients (JAMA 1998 280(3) 2013-9. Can surgical patients (JAMA 1998 280(3) 2013-9. Can J Surg 2001 44(2) 102-11)J Surg 2001 44(2) 102-11)

MayMay↑morbidity compared to standard treatment, ↑morbidity compared to standard treatment, especially sepsis.especially sepsis.

Only beneficial in malnourished surgical patients.Only beneficial in malnourished surgical patients. Did not recommend TPN in the critically ill.Did not recommend TPN in the critically ill. Speculation that Speculation that ↑morbidity due to excess energy ↑morbidity due to excess energy

as lipid or dextrose.as lipid or dextrose. Can we explain these findings?Can we explain these findings?

Complications of TPNComplications of TPN Hyperglycaemia… sepsisHyperglycaemia… sepsis HyperlipidaemiaHyperlipidaemia AzotaemiaAzotaemia HypercapniaHypercapnia Abnormal LFTsAbnormal LFTs Hepatic steatosisHepatic steatosis Impaired immune function.Impaired immune function. Line sepsis.Line sepsis. Bacterial translocation (Deitch 2002, Surgery, 31(3) 241-4)Bacterial translocation (Deitch 2002, Surgery, 31(3) 241-4) Klein 1998 JADA ,7, 795 – 806, Angelico et al Aliment Klein 1998 JADA ,7, 795 – 806, Angelico et al Aliment

Pharmacol Ther 2000 Supp 2: 54-57.Pharmacol Ther 2000 Supp 2: 54-57.

Peritonitis (animal model)Peritonitis (animal model)

0

10

20

30

40

50

60

Survival @ 17 days

100kcal/kg/day125kcal/kg/day150kcal/kg/day175/kcal/kg/day

Peck et al 1989

Intensive Insulin Therapy in Critically Ill Intensive Insulin Therapy in Critically Ill PatientsPatients

Van den Berghe et al. NEJM 2001; 345:1359-1367.Van den Berghe et al. NEJM 2001; 345:1359-1367. PRCT in 1548 adults on surgical ICU. Insulin to maintain PRCT in 1548 adults on surgical ICU. Insulin to maintain

glucose <6.0 mmol vs. insulin to maintain glucose <12 mmol glucose <6.0 mmol vs. insulin to maintain glucose <12 mmol

Also reduced in-hospital mortality by 34%, bloodstream Also reduced in-hospital mortality by 34%, bloodstream infections by 46%, ARF requiring haemo-filtration by 41%.infections by 46%, ARF requiring haemo-filtration by 41%.

0

5

10

15

20

25

ICU mortality ICU >5 daymortality

InsulinConventional

P<0.04

P<0.005

OverfeedingOverfeeding

Overfeeding increases morbidity in metabolically Overfeeding increases morbidity in metabolically stressed patients.stressed patients.

Key paper: Changing concepts of nutrient Key paper: Changing concepts of nutrient requirements in disease. Elia 1995, Lancet 345, requirements in disease. Elia 1995, Lancet 345, 1279-1284.1279-1284.

Energy requirements previously overestimated… Energy requirements previously overestimated… infusion of large amounts of nutrients raises infusion of large amounts of nutrients raises energy expenditure by up to 30%.energy expenditure by up to 30%.

Hypermetabolism offset by inactivity. Hypermetabolism offset by inactivity.

What should we do?What should we do? Impossible to reverse the catabolic response.Impossible to reverse the catabolic response. Overfeeding increases morbidity.Overfeeding increases morbidity. Provision of adequate nutrients to attenuate losses…Provision of adequate nutrients to attenuate losses… But not enough to cause problems of overfeeding.But not enough to cause problems of overfeeding. Although we cannot stop catabolism we can reduce Although we cannot stop catabolism we can reduce

losses with feeding (losses with feeding (Michie 1996 World J. Surg 20(4) 460-4, Michie 1996 World J. Surg 20(4) 460-4, Shaw 1987)Shaw 1987)

ACCEPT study showed improved ICU survival when ACCEPT study showed improved ICU survival when evidence based nutrition guideline is followedevidence based nutrition guideline is followed

Replete losses in recovery - when metabolically Replete losses in recovery - when metabolically stable increase energy and nitrogen.stable increase energy and nitrogen.

Recommendations for energy Recommendations for energy American College of Chest Physicians 25kcal/kg (Cerra, American College of Chest Physicians 25kcal/kg (Cerra,

Chest 1997. 111: 769-78)Chest 1997. 111: 769-78) ASPEN (2002) 20 – 30kcal/kg (JPEN 26(1) Supp)ASPEN (2002) 20 – 30kcal/kg (JPEN 26(1) Supp) Muller (1995) 14kcal/kgMuller (1995) 14kcal/kg Patino et al ’99 20kcal/kg Patino et al ’99 20kcal/kg (World J Surg 23 (6) 553-9) (World J Surg 23 (6) 553-9)

Pomposelli 1994 estimated BMR (Pomposelli 1994 estimated BMR (New Horizons 2, 224 – 9)New Horizons 2, 224 – 9)

Intensive Care Society (ICS) 2000 estimated BMRIntensive Care Society (ICS) 2000 estimated BMR ICS 2004. 25 kcal/kg ICS 2004. 25 kcal/kg ((www.ics.ac.ukwww.ics.ac.uk standards and publications) standards and publications)

Keep energy low while unstable - increase when Keep energy low while unstable - increase when recovering recovering (Mechanick Crit Care Med 2002,18 (3) 597-618)(Mechanick Crit Care Med 2002,18 (3) 597-618)

Energy requirementsEnergy requirements

Many recommendations / methodsMany recommendations / methods All All ESTIMATE ESTIMATE requirementsrequirements Just give a starting pointJust give a starting point Should we just start at 1500kcal?Should we just start at 1500kcal? Or small, medium and large regimens?Or small, medium and large regimens? Monitoring and adjusting MORE important Monitoring and adjusting MORE important Requirements changeRequirements change Patients can arrive looking like…Patients can arrive looking like…

And leave looking like…And leave looking like…

Most Recent RecommendationsMost Recent Recommendations

ESPEN 2006ESPEN 2006 Feeding more than 20 – 25kcal/kg may be Feeding more than 20 – 25kcal/kg may be

associated with poor out come outcome associated with poor out come outcome when metabolically stressed when metabolically stressed

Give 25-30kcal/kg in the anabolic flow Give 25-30kcal/kg in the anabolic flow phase… 10 – 40 daysphase… 10 – 40 days

NICE 25-35kcal/kg when stable – less NICE 25-35kcal/kg when stable – less when metabolically stressed (e.g on ICU).when metabolically stressed (e.g on ICU).

Stress FactorsStress Factors

ControversialControversial Survey of 115 UK dietitians found a vast variation Survey of 115 UK dietitians found a vast variation

in stress factor use (AJ Green 2006)in stress factor use (AJ Green 2006) Designed to estimate energy expenditureDesigned to estimate energy expenditure Achieving energy balance is not beneficialAchieving energy balance is not beneficial Stress factors add energy at the Stress factors add energy at the worstworst time – when time – when

patients are most metabolically stressedpatients are most metabolically stressed ESPEN and NICE say give ESPEN and NICE say give lessless energy when energy when

metabolically stressed.metabolically stressed.

ExampleExample

75kg severely septic male, 28 yrs old.75kg severely septic male, 28 yrs old. BMR = 15.1x 75=692BMR = 15.1x 75=692 Stress factor = 20% – 60%Stress factor = 20% – 60% 2190 – 2920kcal/day2190 – 2920kcal/day Bed bound immobile + 10%Bed bound immobile + 10% 2409 – 3212kcal/day2409 – 3212kcal/day 32 – 43kcal/kg/day32 – 43kcal/kg/day Contrary to ESPEN and NICEContrary to ESPEN and NICE

Other ProblemsOther Problems AACN – equation predictions vary 15-20% in AACN – equation predictions vary 15-20% in

healthy… healthy… 30 – 40% in critically ill30 – 40% in critically ill Other Formulae e.g Ireton Jones?Other Formulae e.g Ireton Jones? Require accurate weight – oedema etc?Require accurate weight – oedema etc?

Practical recommendations.Practical recommendations.

Feed to 20 – 25 kcal/kg or BMR by Schofeild or Feed to 20 – 25 kcal/kg or BMR by Schofeild or low starting point when metabolically unstable.low starting point when metabolically unstable.

Monitor carefully for signs of overfeeding e.g. Monitor carefully for signs of overfeeding e.g. hyperglycaemia, hypercapnia, hyperglycaemia, hypercapnia, ↑lipids,↑lipids, ↑LFTs. ↑LFTs.

Increase energy and nitrogen when recovering.Increase energy and nitrogen when recovering. It is argued that patients build up a nutritional debt It is argued that patients build up a nutritional debt

on the ICU that must be repaid (Villet et al 2005)on the ICU that must be repaid (Villet et al 2005) This debt can only be repaid when the bank is This debt can only be repaid when the bank is

open…open… i.e. when the patient is in an anabolic phase…i.e. when the patient is in an anabolic phase…

Recognising recoveryRecognising recovery

Signs that a patient is entering an anabolic phase Signs that a patient is entering an anabolic phase include:include:

Oedema resolving.Oedema resolving. Hyperglycaemia resolving & Hyperglycaemia resolving & ↓insulin ↓insulin

requirements.requirements. ↓↓C reactive protein levels (CRP)C reactive protein levels (CRP) Patient is mobilising.Patient is mobilising. Appetite returningAppetite returning Serial prealbumin measurements may show the Serial prealbumin measurements may show the

switch to anabolism. Weekly increase over 40mg/l switch to anabolism. Weekly increase over 40mg/l Bernstein et al 1995, Nutrition11(2), 169-171.Bernstein et al 1995, Nutrition11(2), 169-171.

ConclusionsConclusions

Impossible to calculate requirementsImpossible to calculate requirements Many methods – huge variationMany methods – huge variation Just a staring pointJust a staring point Dietitians should be more involved with metabolic Dietitians should be more involved with metabolic

monitoring and adjustingmonitoring and adjusting Keep energy low when stressed – increase in Keep energy low when stressed – increase in

recoveryrecovery Energy expenditure and requirements – not the Energy expenditure and requirements – not the

samesame Stress factors add energy at the wrong timeStress factors add energy at the wrong time Using them is contrary to ESPEN and NICEUsing them is contrary to ESPEN and NICE