Nutritional support is an important component of modern critical care. The practice of vitamin and micronutrient supplementation is variable and official guidelines are not consistent. The primary objective of this observational study is to investigate the clinical practice of micronutrient supplementation during critical illness and to explore the factors underpinning clinical decisions.

Nutritional support is an integral component of modern critical care. Malnutrition is common, but measurement of serum concentrations of most vitamins and micronutrients does not form part of routine care for most critically ill adults in the UK. When measured in a research setting, a large proportion of critically ill patients have low serum concentrations of many essential nutrients. Nutrient deficiency is associated with adverse outcomes, including delirium and increased mortality. To date, it is unclear whether there is a role for micronutrient supplementation in critically ill patients. Official guidelines from the European Society of Parenteral and Enteral Nutrition (ESPEN), American Society of Parenteral and Enteral Nutrition (ASPEN), German Intensive Care Society and Kidney Disease Improving Global Outcome (KDIGO) vary and are contradictory to some extent. Additionally, vitamins B1 and C have been administered as an intervention in the treatment of septic shock and other disease states, but methodological flaws with such studies have left many clinicians with equipoise over the place of vitamin and micronutrients in clinical practice.

There is a need for a well designed, adequately powered intervention study. In preparation, we would like to explore current practice and decision making of doctors, pharmacists and dieticians who are directly involved in prescribing nutritional support.

The primary objective of this observational study is to investigate the clinical practice of micronutrient supplementation during critical illness and to explore the factors underpinning clinical decisions.

Inclusion Criteria:

• healthcare professional who is involved in prescribing vitamins or micronutrients to critically ill patients in the ICU

Exclusion Criteria:

• none

health care professionals working in the ICU

individual participant data will not be made available