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 in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, 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