Nutrition in the ICU

BY
RD.BURHAN AHMAD
 Malnutrition and the inflammatory
process
• Critical illness is associated with a catabolic stress state
– Breakdown of protein reserves
– Movement of protein to extravascular spaces
– Decreased vascular concentrations
– Increased risk for malnutrition, worsens existing malnutrition

– During increased metabolism , amino acids are taken from

skeletal muscle for gluconeogenesis
– 1g of urinary urea nitrogen = 30g lean tissue
– Patient can lose up to 3kg/week of lean body mass if kept NPO.
 Malnutrition and the inflammatory
process
• Albumin/prealbumin are not used to determine nutritional
status in critical illness/hypercatabolic state
• Negative acute phase reactants
– Albumin
– Prealbumin
– Transferrin

– Elevated CRP
– 0.3-1mg/dl minor inflammation
– Greater than 1 ml/dl significant inflammation
 Defining Malnutrition
• “Starvation/Social/Environmental-Related Malnutrition”
– Pure chronic starvation, anorexia nervosa

– “Chronic Disease-Related Malnutrition”

– Chronic diseases => 3mo (ESLD, pancreatic cancer, sarcopenic obesity)

– “Acute Disease or Injury-Related Malnutrition”

– Major infection, burns, trauma, closed head injury
How to Assess for Malnutrition
Nutrition Risk Screening [NRS]
Nutric
Score
 Malnutrition in the ICU
• In an epidemiologic study analysis by Fry DE, et al in Arch
Surg.
2010;145(2):48-151 0f 887, 189 major surgery cases drawn
from the Healthcare Cost and Utilization Project (HICUP)
Nationwide [National] Inpatient Sample (NIS), malnutrition
was associated with the following increased risk of severe
events:

– 4 times more likely to develop pressure ulcers

– 2 times more likely to develop surgical site infections
– 16 times more likely to develop intravascular device infections
– 5 times more likely to develop catheter-associated urinary tract infections
 Malnutrition in the ICU
• As many as 40% of critically ill patients may suffer from
malnutrition

• Malnutrition in critical illness is associated with:

– Impaired immune function
– Impaired ventilatory drive
– Increased risk of infectious morbidity and mortality
– Increased frequency and length of hospital stay
– Higher health care costs
 Malnutrition in the ICU
• Delivering early nutrition support therapy (primarily by the
enteral route) is seen as a proactive therapeutic strategy that
may:

– Reduce disease severity

– Diminish complications
– Decrease LOS in the ICU
– Favorably impact patient outcomes
 Enteral Nutrition in the ICU
• Early Enteral Nutrition (within 48hr):
– Promotes protein synthesis involved in immunologic defense
– Acts as stress ulcer prophylaxis
– Lowers risk for nosocomial infections by stimulating GI blood flow,
promotes maintenance of tight junctions between cells, supports
immunocytes that from GALT
– Maintain gut integrity
– Reduces hospital LOS, overall hospital mortality
 Enteral Nutrition in the ICU
• Primary concern for EN in the ICU = gut ischemia
– Occurs in < 1% patients

– Patients requiring low dose stable vasopressors who had early

delivery of EN had lower ICU mortality (2.5% vs 28.3%: p =0.03)
and hospital mortality (34% vs 44%: p less than 00.1) than those
receiving late EN, respectively

– Results suggest that the use of concomitant vasopressors

(especially with stable or decreasing doses) should not
preclude a trial of EN
 Enteral Nutrition in the ICU
• Guidelines discourage early EN in critically ill patients
who are both Hemodynamically unstable and have not
had their intravascular volume fully resuscitated

• In every unstable patients, EN may not have priority,

and potential positive effects of EN are unlikely to help
improve instability
 Assessing Tolerance to EN
• EN should be withheld:
– If mean arterial blood pressure < 50 mm Hg
– In patients for whom catecholamine agents (eg,
norepinephrine, phenylephrine, epinephrine, dopamine)
are being initiated
– Escalating doses are required to maintain hemodynamic
stability
• Ensure adequate bowel regimen
• Pro-motility agents
– Metoclopramide, erythromycin
• May need post pyloric tube
• Diarrhea = Infectious related? Med related?
Osmotic Diarrhea?
 Gastric Residual Volumes
• Several RCTs have shown GRVs do not correlate with
incidences of PNA, regurgitation, or aspiration, and lead
to potential tube clogging, inappropriate cessation of
EN, and consumption of nursing time

• Per ASPEN guidelines: do NOT check residuals, and for

those ICUs where GRVs are still utilized, hold for >500ml
residuals

• Per Loyola as of 6/017: No need to check residuals

 Preventing Aspiration
• HOB should be >45 degrees
• Daily oral care
• Reduce level of sedation when possible
• Minimize transportation in and out of the ICU for
tests/procedures
• Consider post-pyloric tube for high risk aspiration or previous
incidences of aspiration PNA
– Although small bowel EN decreases the risk of pneumonia, there is no
difference in mortality or LOS between small bowel and gastric EN
 Contraindications to EN
• Hemodynamically unstable and have not had their
intravascular volume fully resuscitated
• Bowel obstruction
• Severe and protracted ileus
• Major upper gastrointestinal bleeding
• Intractable vomiting or diarrhea
• Gastrointestinal ischemia
• High output fistula
 Parenteral Nutrition
• Supplemental PN has been shown to increase infection,
length of stay, and total cost
• Current ASPEN recommendations:
– Provide hypo-caloric enteral feedings as able (i.e, trophic TFs) until day
7, then initiate supplemental PN
– If patient is at low nutrition risk, exclusive PN should be withheld for
the first 7 days following ICU admission if the patient cannot maintain
volitional intake and if early EN is not feasible
– If patient is at high nutritional risk and EN is contraindicated, initiate
PN as soon as possible following ICU admission
 When should PN be initiated in the adult
critically ill patient at low nutrition risk?
• In the patient at low nutrition risk (NUTRIC score ≤5),
exclusive PN be withheld over the first 7 days following ICU
admission if early EN is not feasible.

• Casaer et al showed that those patients for whom use of PN

was started on ICU day 3 had worse infectious morbidity and
were less likely to be discharged alive than those patients for
whom PN was started instead on day 8.

N Engl J Med. 2011;365(6):506-517

 Contraindications to PN
• Hyper osmolality
• Severe hyperglycemia
• Severe electrolyte abnormalities
• Volume overload
 Difference In Outcome Between The
Use of EN or PN For Adult Critically Ill Patients
• In 12 studies, 9 reported significantly less infectious
complications with EN than PN
• (RR = 0.56; 95% CI, 0.39–0.79; P < .00001)

• ICU LOS also was shorter with EN compared with PN by nearly

1 full day
• (WMD = −0.82 days; 95% CI, −1.29 to −0.34; P = .0007)

Stephen A. McClave et al. JPEN J Parenter

Enteral Nutr 2016;40:159-211
 Calculating Nutrient Needs
• Weight based equation for calorie needs:
– 24-30kcal/kg actual body weight
– If BMI 30-50, use 11-14kcal/kg actual body weight
– If BMI 50, use 22-25kcal/kg IBW

Protein needs:
– 1.2-2g/kg in septic/ICU patients
– If BMI 30-40, from 2.0g/kg IBW
– If BMI > or equal to 40, up to 2.5g/kg IBW
 Dosing Weight
• Actual weight may be inaccurate in trauma and burn patients who
have been fluid resuscitated

• Lean body mass is highly correlated with actual weight in persons of

all sizes

• Usual weights may not be available

• Best:
– Adjusted BW/ Dosing weight = IBW + 0.25 (ABW - IBW).

• An alternative method: use 10 percent of the ideal body weight.

Dosing weight = 1.1 * IBW.
Nutritonal Support in
Specific Conditions
 Respiratory failure (ARF)
• Specialty high-fat/low-carbohydrate formulations designed to
reduce CO2 production should not be used in ICU patients
with (ARF)

• Fluid-restricted energy-dense EN formulations should be

considered for patients with (ARF)
• (especially if in a state of volume overload)

• Serum phosphate concentrations should be monitored closely

.
 Renal Failure
• ICU patients with AKI should be placed on a standard enteral
formulation with protein (1.2–2 g/kg per day) and energy (25–
30 kcal/kg/d)

• Patients receiving frequent hemodialysis should receive

increased protein, up to a maximum of 1.2- 2.5 g/kg/d.

• Protein should not be restricted in patients with renal

insufficiency as a means to avoid or delay initiating dialysis
therapy
 Hepatic Failure
• A dry weight or usual weight should be used instead of actual
weight in predictive equations

• Protein should not be restricted as a management strategy

aimed at reducing hepatic encephalopathy.

• This may worsen nutrition status, decrease lean muscle mass,

and ironically lead to less ammonia removal.
 Hepatic Failure
• EN be used preferentially when providing nutrition therapy in
ICU patients with acute and/or chronic liver disease.

• Standard enteral formulations should be used in ICU patients

with acute and chronic liver disease.

• There is no evidence of further benefit of branched-chain

amino acid (BCAA) formulations on coma grade
 Sepsis
• Critically ill patients should receive EN therapy within 24–48
hours of making the diagnosis of severe sepsis/septic shock as
soon as resuscitation is complete and the patient is
Hemodynamically stable.

• Exclusive PN or supplemental PN should not use in

conjunction with EN in the acute phase of severe sepsis or
septic shock, regardless of patients’ degree of nutrition risk.
 Sepsis
• 10–20 kcal/h or up to 500 kcal/d for the initial phase of sepsis,
advancing as tolerated after 24–48 hours to >80% of target
energy goal over the first week.

• 1.2–2 g protein/kg/d.
Landmark Articles in ICU nutrition