Intensive Nutrition in Critically Ill Adults

Overview

Despite the widespread use of nutrition therapy, no large scale randomized controlled trials (RCTs) have demonstrated positive outcomes with delivery of nutrition therapy early in critical illness, with some showing no effect with delayed nutrition or even harm. There are several possible reasons for the lack of observed benefit from RCTs to date; interventions have been short in duration (usually 3-10 days after intensive care unit (ICU) admission), perhaps applied at the incorrect time in regards to the patients metabolism and recovery, do not consider the patients nutrition risk, and have not addressed what happens to nutrition intake post ICU in critically ill individuals. This may explain why RCTs to date have not observed any positive associations with the delivery of nutrition; our focus to date may have been on the wrong stage of illness. A future study is thus urgently needed, which addresses the deficiencies in current RCTs by optimizing nutrition delivery for the whole hospital stay and collecting meaningful clinical, process and outcome data, which will potentially inform a larger trial of a similar nature. This initial study aims to determine whether optimization of energy using a pre-tested supplemental parenteral nutrition (PN) strategy in the Intensive Care Unit (ICU) and an intensive nutrition intervention in the post ICU period will deliver more total energy than standard nutrition care during hospital admission in a group of critically ill patients with at least one organ system failure.

Background: Nutrition is a commonly provided therapy in critical illness, but data about effectiveness is sparse. Best practice guidelines recommend enteral nutrition (EN), a specialised solution delivered into the gastrointestinal tract, as the first line of nutrition therapy. The majority of best practice guidelines also recommend delivery of energy and protein amounts close to predicted requirements in critical illness over the course of Intensive Care Unit (ICU) admission, however the only evidence to support this is from observational data. Although recommended that energy and protein requirements be met, and observational data suggests this is of benefit, there are practical challenges with the provision of EN. International practice surveys report the average energy and protein provided is approximately 59% of the patients predicted requirements, for multifactorial reasons. The addition of parenteral (intravenous) nutrition has been proposed as a method to provide additional energy when EN is insufficient, termed supplemental parenteral nutrition (PN). The ability of this strategy to deliver additional energy and protein to patients during critical illness has been proven in several feasibility/pilot trials, but the benefit on clinical and functional outcomes is unknown. Despite observational data suggesting benefit when energy and protein delivery is optimised close to requirements, no large scale randomised controlled trials (RCTs) have confirmed improved clinical outcomes in critical illness, with some showing no effect with delayed nutrition or even harm. There are several possible reasons for the lack of observed benefit from RCTs to date; the interventions may have been applied at a time when the patient's metabolism is not in a phase of recovery; interventions have been short in duration and; studies have not addressed what happens to nutrition intake in the post ICU period of hospitalisation in critically ill individuals. Aims: To determine whether the use of a pre-tested supplemental PN strategy in the ICU and an intensive nutrition intervention after discharge to the hospital ward is feasible and will deliver more total energy than standard nutrition care over the entire hospital stay, in critically ill patients with at least one organ system failure. A further aim is to develop a research program that will determine whether optimisation of energy to critically ill patients over the entire period of hospitalisation improves clinically-meaningful outcomes. Hypothesis: In critically ill patients with at least one organ failure, the use of a supplemental PN strategy in ICU and an intensive nutrition intervention on the hospital ward will lead to an increase in daily energy delivery of at least 15% over the entire hospital stay when compared to standard care. Fifteen percent has been estimated as the minimum acceptable clinical difference between the two groups. Objectives: The major objectives are: 1. To determine whether the whole hospital nutrition intervention leads to increased amounts of total energy delivered over the period of hospital stay 2. To determine if the whole hospital nutrition intervention is safe in regards to adverse effects 3. To determine if the post-ICU nutrition intervention is practically feasible when applied in multiple hospitals, across multiple wards 4. To measure the clinical outcomes in patients and provide information to assist design of a larger randomised controlled trial