Nutritional Assessment in the Critically Ill
OVERVIEW
- poor nutritional state is a common feature of critically ill patients, either pre-existing or as a result of the illness
HISTORY
- recent weight loss
- thorough dietary assessment
- changes in appetite or bowel habit
- presence of GI symptoms
- stomas
- liver disease
- diabetes mellitus
- medications (may effect absorption of micronutrients, produce N+V)
- allergies (medications and dietary)
- social: where they live, who cooks, family support, alcohol intake, smoking and illicit drug use
- ROS: immunocompetence, infections, organ function
EXAMINATION
- assessment of metabolic activity (T, HR, BP, RR, level of arousal)
- hydration status
- muscle wasting
- signs of micro-nutrient deficiency (glossitis, angular stomatitis, anaemia, bleeding gums, skin/hair/nail condition)
INVESTIGATIONS
Bedside
- urine: ketones
- ABG: metabolic state
Laboratory
- electrolytes: refeeding syndrome
- albumin: chronic nutritional state
- prealbumin: acute nutritional state
- transferrin: synthetic function of liver
- coagulation: synthetic function of liver
- fat soluble vitamin levels: DEKA
- water soluble vitamins levels: thiamine, zinc, selenium, B12, folate
Special Tests
- delayed hypersensitivity skin testing
- total lymphocyte count
- anthropometric measurements: mid-arm muscle circumference and skin fold thickness
- indirect calorimetry: measures energy expenditure (VO2, VCO2)
- nitrogen balance: inaccurate in liver and renal failure
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC
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Hi Chris, great summary.
Important to note influence of CRP when interpreting albumin, micronutrient and trace elements levels.
Also important to recognise that mid-arm muscle circumference and tricep skin folds as well as subjective physical assessment are not reliable methods to identify patients with lower than normal muscularity at ICU admission (with fluid often masking muscle wasting)(1, 2). Quantification of muscularity using CT scans is the reference method to identify patients with low muscularity – although time consuming and specialist training required. Bedside ultrasound (imaging muscle thickness at biceps & quadriceps) shows the most promise for this purpose although more validation required before the method can be used as part of routine care (3, 4).
Cheers,
Kate
ICU Dietitian, Melbourne