Critical Care

Question 1

Describe the different levels of care

Answer 1

Level 0:
patients needs can be met in ward setting

Level 1:
patients needs can be met in ward setting with enhanced support/observations
risk of deterioration

Level 2:
support for at least one failed organ system
post operative care
step down from higher level of care

Level 3:
advanced respiratory support (mechanical ventilation) alone or basic respiratory support plus 2 or more failing organ systems.

Question 2

Describe how patients are nutritionally. screened/assessed on critical care ward.

• describe the role of anthropometry on CCU

Answer 2

all patients expected to be mechanically ventilated for > 48 hours need nutritional assessment.

Screening and assessment:

MUST not accurate.
NUTRIC (Nutrition Risk in the Critically Unwell)
NRS - 2002 (nutrition risk screening)
Specifically designed for use in crit care environment.

Anthropometry:

• useful tool on CCU but several barriers to obtaining accurate anthropometric measures.
• should be interpreted with caution.
• inaccurate weights (bed scales not calibrated)
• may be unable to obtain weight history
• fluid retention

Often not appropriate to use HGS.

Question 3

Describe how metabolism can change during critical illness.

Answer 3

ebb phase, flow phase, recovery phase.

Ebb phase:
- days 0-5 post admission
- happens immediately after injury/illness.
- metabolism slows
- body can generate up to 75% glucose

Flow phase:
- gradual increase in metabolism to baseline and then peaks
- can lose up to 2% muscle mass/day
- flow phase appears to last as long as the injury/illness lasts

Recovery phase:
- metabolism slowly decreases back to baseline
- catabolism declines, body becomes anabolic again

Question 4

Describe nutrition delivery in critical illness

Answer 4

Ebb phase:
- 0-5 post ICU admission
- requirements: 15-25kcal/kg/day

Flow phase:
- day 5 + post illness
- requirements: 25-40kcal/kg/day

Recovery:
- achieve energy balance
- meet nutritional requirements

Question 5

Estimating nutritional requirements on Critical Care:

Energy
(overfeeding vs underfeeding)

Protein
?obesity

Answer 5

ENERGY:

Indirect calorimetry is the gold standard for estimating energy requirements in critically ill patients.

If no access to IC machine, weight based predictive equations are used.

• Mifflin St Jeor/ Penn State (uses Mifflin St Jeor)
• Harris Benedict
• ESPEN 20-25 or 25-30kcal/kg/day (depends whether anabolic/catabolic)

Overfeeding vs Underfeeding:
research shows beneficial to give hypocaloric nutrition (70% needs) during first week (?ebb phase) of admission.

PROTEIN:
1.2-1.5g/kg/day

obese patients:
ESPEN:
1.3 g/kg ABW/day
ASPEN:
2.0 g/kg IBW/day (BMI of 30–39.9)
2.5 g/kg IBW/day (BMI ≥ 40)

Question 6

Describe some medications/drugs commonly used on ICU that may interfere with nutrition.

Answer 6

Medication with extra calories:
- propofol 1kcal/ml
- citrate/glucose based dialysis solutions

Analgesics/sedatives:
- reduce gut motility: constipation

Laxatives & anti-diarrhoeal agents

IV Fluids:
- can contribute to fluid retention

Prokinetics:
- increase gut motility: increase gastric emptying

Antibiotics:
- Lots of ICU patients are placed on broad spectrum antibiotics which can alter gut microbiome and cause GI upset

Diuretics e.g., furosemide
- risk of electrolyte derangement (hypokalaemia, hypo/hypernatraemia