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!