ICU Flashcards
Who would be considered to be critically ill?
- Sepsis
- Trauma (e.g., motor vehicle accident, traumatic brain injury)
- Burns
- Organ failure (pulmonary, renal, liver)
- Severe pancreatitis
- Surgical subsets (e.g., open abdomen)
WHat is metabolic stress?
Metabolic stress is a hypermetabolic, catabolic response to acute injury or disease
What does severity of stress depend on?
Severity of stress = Severity of injury
Tools to measure severity of stress?
Tools: Glasgow Coma Scale (GCS), Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation (APACHE)
Tools for nutrition requirements in stress
Nutrition assessment in the critically ill = NUTRIC or NRS-2002
• Combines metabolic stress with nutrition parameters
How does length of stay in ICU affect the nutrition risk?
the more days in ICU, the higher the nutritional risk
what is SOFA?
Sequential organ failure assessment score (respiratory, cardiovascular, hepatic, coagulation, renal and neurological)
What are the components of NRS-2002
Nutritional status score + severity of disease + age
Score above and below 3 on NRS-2002
Score >3: the patient is nutritionally at risk and the nutrition care plan is initiated
score < 3: weekly rescreening of the patient e.g. if the patient is scheduled for a major operation, a preventative nutrition care plan is considered to avoid the associated risk status
JC is an 80-year-old lady in long term care. Over the past week she has been eating less than half of her meals. No obvious weight changes. She is admitted because of a motor vehicle accident in which she suffered a severe head injury. What is her NRS-2002 score?
1 for age + 3 for head injury + 2 for food= 1. Whole body protein catabolism
2. Hyperglycemia
what are the 2 major metabolic changes in metabolic stress?
- Whole body protein catabolism
2. Hyperglycemia
Name counter-regulatory hormones and cytokines that play a role in metabolic stress
counter-regulatory hormones: glucagon and cortisol
cytokines: IL-6 (messengers in the body to stimulate immune response)
Describe protein catabolism pathway in metabolic stress
AA from lean tissue (respiratory tissue, muscles) are released into the circulation and preferentially taken up by the liver because the liver has 2 important roles during stress
1. maintaining energy levels
2. making proteins that are important in immune response and healing wounds
thus, lean tissue is sacrificed to support the role of the liver
Describe hyperglycemia pathway in metabolic stress
liver produce glucose
normally if there is high BG, normally there is a feedback mechanism to stop excessive glucose production. which is not present in this case
this is refractory somatic glucose production
there is also insulin resistance- glucose in the blood is not being used well and stays in the blood
what happens to GLUT4 during metabolic stress?
normally glucose stimulates a cascade of events via a receptor that eventually results in release of GLUT4 vesicle which goes to a plasma membrane so glucose can freely enter the cell
during metabolic stress- for some reason this does not work properly and glucose stays in the blood
Positive vs negative acute phase proteins
acute phase protein are proteins that are proteins that participate in immune signalling
albumin is negative acute phase protein (during stress albumin levels drop)-
albumin levels in stress have nothing to do with nutrition
fibrinogen is a positive acute protein
Why is there a loss of function in metabolic stress
due to body protein catabolism
Why is there a high chance of malnutrition in metabolic stress
whole body catabolism also increases protein and energy requirements and thus will most likely result in malnutrition (due to increased demands)
the greater the metabolic response (catabolism) the more likely the patient will be malnourished-> the more nutrition needs to be provided
Goal of nutrition care in the ICU
nutrition therapy attenuates the metabolic response to stress, prevents oxidative cellular injury, and favourably modulates the immune response.
lower metabolic response = lower chance of malnutrition= lower chance of losing lean tissue = better recovery
Benefits of EN in modulating stress and improving outcomes
- Maintain gut integrity
- Modulate metabolic response to stress
- Modulate systemic immune response
- Prevent bacterial translocation
Which med will affect the enedgy supplied by nutr support
Subtract propofol energy from total
Is EN or PN preffered ?
EN
When should EN be initiated? What about PN?
EN: If at high risk, aim to start within 24-48 hours and reach >80% of goal within 72hrs.
PN: If high risk (NRS >5) and EN not
feasible, aim to start PN as soon as possible.
EPSEN aim to start EN in all within 48 hours
Guidelines for Hemodynamic instability and EN
In the setting of hemodynamic compromise or instability, EN should be withheld until the patient is fully resuscitated and/or stable. Initiation/re-initiation of EN may be considered with caution in patients undergoing withdrawal of vasopressor support.
Withhold EN if any of the following apply:
• Hypotensive: Mean arterial blood pressure <50 mm Hg
• Calculated using systole and diastole BP: diastole x 2 + systole/3
• Initiation of catecholamines/ vasopressors (norepinephrine, phenylephrine, epinephrine,
dopamine)
• Increased needs of catecholamines to maintain hemodynamic stability
Can consider cautious EN if patient on chronic, stable, low dose vasopressors; Monitor GI tolerance!
What is more important- protein or energy?
In the ICU and critically ill patient, protein intake is more highly related to positive outcomes than provision of energy.
What can a patient benefit from if it is receiving suboptimal EN
Patients with suboptimal EN due to frequent interruptions
may benefit from modular protein flush
What is the recommended protein range in general? Sepsis? Renal replacement? Burn victims?
- Range of 1.2-2.0 g/kg actual body weight per day
- Some use 1.5-2.0 g/kg/d in sepsis (ASPEN pg 466)
- Continuous renal replacement 2-2.5 g/d (pg 479)
- Higher in burn or multi-trauma patients (up to 2.5g/kg)
- Dose higher than previously thought overa;;
How do we use nitrogen balance for protein estimation in ICU?
Use of NPC:N and nitrogen balance of limited use in ICU
• (1 g N = 6.25g protein)
what is the recommended method for energy calculation
Indirect calorimetry (IC) should be used to determine energy requirements
How can we estimate energy needs?
• 25-30 kcal/kg/d (not for obese though)
• Penn State, Ireton-Jones, Swinamer are no more accurate than Harris-Benedict or Mifflin St. Jeor
• Use dry weight or usual body weight
Do not forget to account for propofol
what % of tagret energy is provided in EN to obese patients
should not exceed 65-70%
what is the recommended kcal/kg for BMI 30-50 and BMI 50+
11-14 kcal/kg for ACTUAL body weight BMI 30-50
for BMI >50 its 22-25 kcal of IDEAL body weight
suggested protien range for BMI 30-40 and BMI>40
2g/kg for BMI of 30-40
2.5 g/kg for BMI>40
Patient has edema, how might you determine his dosing weight?
A. Ask family for UBW
B. Use bed scales
C. Check medical history/records for recent weight
D. Use all three methods
E. UseA&C
E. UseA&C
how many kcal/ml does propofol contain?
1.1 kcal/ml
What are the recommendations for EN in critically ill? Formula, volume, timing?
- If the gut works, use it!
- Trophic feeds (10-20 ml/h or up to 500 kcal/d) Polymeric formula usually acceptable
- Nutrient dense, high protein formula usually best Continuous EN feeds
Where should be the EN placed in critically ill? Why? WHich tube?
“in most critically ill patients, it is acceptable to initiate EN in the stomach”
• Easier to place
• May decrease time to initiation of EN
• If patient at risk of aspiration or cannot tolerate gastric feeds, consider SB (small bowel) feed.
NG or OG tube is preferred over G-tube as critical feeding is usually short-term
re-evaluate over time
Describe volume-based feedings?
< 50% ICU patients ever reach target energy intake during ICU stay due to constant pauses in feeding
Volume-based feedings allow to make up for missed feedings: - Prescribed 60 to 80% of needs
• Volume based feeding calculation:
24 hr volume goal - volume already received = volume remaining for today Volume remaining for today / hours remaining for today = New rate
When to start nutrition support in critically ill?
EN or PN?
- ASPEN recommends that EN should be started within 24-48hours of admission when the patient is hemodynamically stable and is at high nutritional risk.
- PN should be reserved for those cases of prolonged NPO status lasting longer than 7 days, or when patient is malnourished or EN access cannot be maintained/EN cannot meets needs (defined a: >60% of energy/protein requirements within >7-10 days).
ASPEN: EN over week one of hospitalization with NRS2002 score ≤ 3
Patients with NRS2002 score < 3 who cannot maintain volitional intakes do not require specialized nutrition therapy over the first week of hospitalization in the ICU
• Risk of EN may exceed benefits
• Reassess daily, if worsen (metabolic state, disease severity, expected LOS) may
warrant EN as benefits may exceed risks
• Note: if NRS2002 score < 3 but u think the patient will be there for a while-> start right away
ASPEN: EN over week one of hospitalization with NRS2002 score ≥5
- Patients at high risk, NRS2002 score ≥5 or severely malnourished, should be advanced toward goal as quickly as tolerated over 24-48 h while monitoring for refeeding syndrome.
- Efforts to provide >80% of estimated or calculated goal energy and protein with 48-72 h should be made to achieve clinical benefits of EN
- Lowest mortality if > 80% met but even >10 kcal/kg/d beneficial
- Needed to maintain gut barrier function
- Reduce mortality (high risk patients)
- Also keep checking that the patient is hemodynamically stable
ASPEN: PN in brief
- Low risk NRS2002 < 3, withhold exclusive PN for 1st 7 days if volitional intake inadequate and early EN not feasible
- High risk NRS2002 > 5 or malnourished, and EN not feasible, initiate PN as soon as feasible.
- Hypocaloric PN (<20 kcal/kg/d or 80% EEE) with adequate protein (> 1.2 g/kg/d) over 1st week in ICU
- Also use PN in high or low risk patients if EN unable to meet > 60% goal after 7-10 days
- Can use EN&PN
- Withhold soybean oil lipids?; If concern for EFAD use divided 2 doses/wk approach
- Glucose target range (<10 mmol/L) for ICU
- d/c PN when EN > 60% target energy