Timing of the initiation of parenteral nutrition in critically ill adults

Abstract

BackgroundCritical illness in hospitalized patients induces anorexia: aninability to eat suitably, predisposing to nutritional deficit,weakness, infections, increased duration of mechanicalventilation, delayed recovery and death [1]. To date,whether artificial nutritional support improves outcomesfor critically ill patients is unclear. Enteral nutrition isassociated with fewer complications than parenteral nutri-tion, and is less expensive [2], but enteral nutrition alonedoes not often achieve caloric targets. Combining paren-teral and enteral nutrition could prevent nutritional deficit.However, this strategy may carry the risk of overfeeding,which has been associated with complications such as liverdysfunction [3]. Current clinical practice guidelines fornutritional support in critically ill patients are largely basedon expert opinion, and differ substantially across conti-nents, in particular about the timing to start parenteralnutrition. The European Society of Parenteral and EnteralNutrition (ESPEN) recommends the commencement ofparenteral nutrition within 2 days after admission to theintensive care unit (ICU) for patients who cannot be ade-quately fed enterally [4], while the American and Canadianguidelines recommend early initiation of enteral nutrition,but suggest starting parenteral nutrition after a week inpatients who are not malnourished at baseline [5].SummaryCasaer and coworkers [6] in a randomized, multicenter trial,comparedanearlytoalateinitiationofparenteralnutritioninadults admitted to the ICU who were not malnourished atbaseline [body-mass index (BMI) of C17] in order to sup-plement insufficient enteral nutrition. The primary endpoints were the number of days spent in ICU (for survivorsand non-survivors), and the time to discharge from the ICU.In 2,312 patients, parenteral nutrition was initiated within48 h after ICU admission, whereas in 2,328 patients, it wasnot initiated before the eighth day from admission. ThemedianstayintheICUwas1 dayshorterinthelate-initiationgroup than in the early-initiation group (3 vs. 4 days,respectively, P = 0.02), which was reflected in a relativeincrease of 6.3% of the likelihood of earlier discharge alivefrom the ICU [hazard ratio 1.06, 95% confidence interval(CI), 1.00–1.13, P = 0.04]. Considering the secondary out-comes, patients in the late-initiation group had fewer healthassistance related infections (22.8 vs. 26.2%, P = 0.008), alowerincidenceofcholestasis(32.6vs.38.4%,P\0.001),areduction in the proportion of patients requiring more than2 days of mechanical ventilation (36.3 vs. 40.2%,P = 0.006), a median reduction of 3 days in the duration ofrenal replacement therapy (7 vs. 10 days, P = 0.008) and areduction in mean health care costs of €1,110 as comparedwith the early-initiation group (€16863 vs. €17973,P = 0.04). The safety outcomes (in-hospital mortality rates,survival at 90 days, rates of nutrition-related complications)weresimilarinthetwogroups,buthypoglycaemiawasmorecommon in the late-initiation group patients (3.5 vs. 1.9%,P = 0.001). Although enteral nutrition was initiated if pos-sible in the majority of patients, the post hoc subgroupanalyses including patients for whom early enteral nutritionwas contraindicated showed the same results.