Effectiveness of continuous enteral nutrition versus intermittent enteral nutrition in intensive care patients: a systematic review

Background Feeding by nasogastric tube in critically ill adults is a controversial form of nursing care due to its great clinical variability. Research does not indicate which is the best form of administering enteral nutrition. Objectives To determine the existing evidence regarding the effectiveness of continuous enteral nutrition versus intermittent enteral nutrition by measuring the nutritional status, digestive intolerance and complications in adult patients with a nasogastric tube in an intensive care unit. Inclusion criteria Types of participants Patients over the age of 18, with nasogastric tube and enteral nutrition, in an intensive care unit. Types of intervention(s) Continuous enteral nutrition: gravity administered or by feeding pump continuously for 12 hours/day or more. Intermittent enteral nutrition: administered by bolus, gravity or feeding pump several times a day with a rest between feeds. Types of studies Randomized clinical trials, clinical trials without randomization, and before and after studies. Types of outcomes The selected studies included at least one of the following outcome measures: Nutritional status Digestive intolerance Bronchoaspiration Search strategy The search was conducted in Cochrane Library, MEDLINE, EMBASE, AMED, CINAHL, DARE, National Research Register, Cuiden, Lilacs, IME, and Web of Science. Grey literature sources were also searched and hand-searching was performed to locate additional studies. Methodological quality The studies were assessed by two independent reviewers. The methodological quality of those which fulfilled the inclusion criteria was assessed with the Joanna Briggs Institute critical appraisal form for effectiveness studies. Data collection Data was collected with an ad-hoc form by two independent reviewers. Data synthesis The studies presented lacked homogeneity both in the way of defining intermittent enteral nutrition and in the measurement of the result variables, and so a meta-analysis was rejected. Statistical pooling was not possible therefore the findings are presented in a narrative form. Results Following the search, 2853 studies were retrieved of which six articles that fulfilled the inclusion criteria were finally included. Nutritional results: On the seventh day after commencing enteral nutrition, one included study concluded that patients with intermittent nutrition were more likely to meet the caloric objective than those with continuous nutrition (chi2 = 6.01, p = 0.01) and another included study concluded the caloric objective was achieved in 30 out of 51 patients in continuous nutrition and 52 out of 56 in intermittent nutrition (p = .000). Digestive intolerance: There were no significant differences between groups in any of the studies. Bronchoaspiration: One included study showed that intermittent nutrition offered a lower risk of aspiration pneumonia (8 out of 56, p = 0.00) than continuous (26 out of 51, p = 0.049). OR = 0.146, (95% CI = 0.062-0.413; p = .000). Conclusions There is not sufficient evidence to support a continuous or intermittent enteral nutrition method, although the two highest quality included studies established that the intermittent form obtained better nutritional results in less time and with a reduced risk of aspiration pneumonia. Implications for practice The protocols of the studies reviewed reflect the variability of clinical practice regarding the administration method, the way of interpreting digestive intolerance and the taking of decisions concerning the continuity of enteral nutrition. Implications for research It would be relevant to continue RCTs which compare both methods of administration, taking into account the variables studied in this review, and also all the factors that affect these patients such as their pathology, severity, medication, use of ventilator and the position of the patient when feeding.