Intermittent versus continuous tube feeding in patients with hemorrhagic stroke: a randomized controlled clinical trial

Bolus Versus Continuous Enteral Feeding for Critically Ill Patients: A Systematic Review and Meta-Analysis

Enteral feeding is a crucial aspect of nutritional support for critically ill patients. However, the optimal feeding approach, whether bolus or continuous, remains a subject of debate. This systematic review and meta-analysis aimed to compare the outcomes of bolus feeding and continuous enteral feeding in critically ill patients. A systemic search was carried out in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL) Ultimate, Web of Science, Scopus, and Google Scholar to identify relevant studies. To ensure that we obtain the latest evidence on the topic, the search was limited to the last five years. Risk of bias assessments and meta-analyses were performed for relevant clinical outcomes. A total of nine randomized controlled trials (RCTs) were included, involving a total of 863 patients. All the studies were published between 2020 and 2023. High-risk performance bias was observed in seven studies, with unclear risk in two studies. In terms of clinical outcomes, no statistically significant differences were found between bolus and continuous enteral feeding in terms of diarrhea (odds ratio {OR} 0.60, 95% CI 0.27 to 1.30, p=0.20), constipation (OR 1.52, 95% CI 0.91 to 2.53, p=0.11), vomiting (OR 0.74, 95% CI 0.36 to 1.49, p=0.39), distention (OR 0.70, 95% CI 0.14 to 3.58, p=0.66), aspiration (OR 0.61, 95% CI 0.16 to 2.73, p=0.48), and gastric residual volume (GRV) (OR 0.80, 95% CI 0.30 to 2.15, p=0.66). Furthermore, no significant differences between bolus and continuous feeding were observed in terms of intensive care unit (ICU) mortality (OR 0.66, 95% CI 0.42 to 1.04, p=0.07), hospital mortality (OR 0.57, 95% CI 0.31 to 1.03, p=0.06), ICU length of stay (OR 0.70, 95% CI 0.50 to 1.90, p=0.25), and hospital length of stay (OR -0.86, 95% CI -3.04 to 1.33, p=0.44). This systematic review and meta-analysis suggest that bolus and continuous enteral feeding methods exhibit comparable outcomes in critically ill patients. However, both ICU mortality and hospital mortality outcomes were close to achieving statistical significance, which favored the continuous feeding approach.

The effect of intermittent versus continuous enteral feeding for critically ill patients: a meta-analysis of randomized controlled trials

Objectives

The appropriate strategy for enteral feeding in critically ill patients still remains controversial. Therefore, we conducted this meta-analysis to compare the effect of intermittent versus continuous enteral feeding method for critically ill patients.

Methods

Electronic databases including PubMed, Embase, Scopus, and Cochrane Library were searched up to April 10th, 2023 for randomized controlled trials evaluating the effect of intermittent versus continuous enteral feeding for critically ill patients. The primary outcomes were feeding intolerances, including diarrhea, vomiting, distension, constipation, gastric retention, and aspiration pneumonia. The secondary outcomes were mortality in intensive care unit (ICU), length of stay in ICU, and achievement of nutritional goal.

Results

Thirteen studies with a total of 884 patients were analyzed in this meta-analysis. Overall, the use of intermittent enteral feeding was associated with higher incidence of diarrhea (OR 1.66, 95%CI 1.13 to 2.43, I2 = 16%) and distension (OR 2.29, 95%CI 1.16 to 4.51, I2 = 0%), lower incidence of constipation (OR 0.58, 95%CI 0.37 to 0.90, I2 = 0%), and longer length of ICU stay (MD 1.09, 95%CI 0.53 to 1.64, I2 = 0%). Moreover, no significant difference was identified for other outcome measures.

Conclusion

In critically ill patients, the implementation of intermittent enteral feeding was associated with higher incidence of diarrhea and distension, longer length of ICU stay, but lower occurrence of constipation. Nevertheless, the absence of sufficient high-quality randomized controlled clinical trials precludes any definitive conclusions regarding the optimal approach to enteral feeding in this population. There is an imperative need for more studies to further assess the efficacy of the two enteral feeding strategies.

Intermittent feeding and circadian rhythm in critical illness

PURPOSE OF REVIEW

Circadian rhythms, i.e., periodic oscillations in internal biological processes, modulate metabolic processes such as hormonal signalling, nutrient absorption, and xenobiotic detoxification. Meal timing is a strong entraining cue for peripheral clocks in various organs, and eating out of circadian phases can impair glucose, gastrointestinal, and muscle metabolism. Sleep/wake cycles and circadian rhythms are extremely disrupted during critical illness. Timing of nutritional support may help preserve circadian rhythms and improve post-Intensive Care Unit (ICU) recovery. This review summarises circadian disruptors during ICU admission and evaluates the potential benefits of intermittent feeding on metabolism and circadian rhythms.

RECENT FINDINGS

Rhythmic expression of core clock genes becomes rapidly disturbed during critical illness and remains disturbed for weeks. Intermittent, bolus, and cyclic enteral feeding have been directly compared to routine continuous feeding, yet no benefits on glycaemic control, gastrointestinal tolerance, and muscle mass have been observed and impacts of circadian clocks remain untested.

SUMMARY

Aligning timing of nutritional intake, physical activity, and/or medication with circadian rhythms are potential strategies to reset peripheral circadian rhythms and may enhance ICU recovery but is not proven beneficial yet. Therefore, selecting intermittent feeding over continuous feeding must be balanced against the pros and cons of clinical practice.

Are periods of feeding and fasting protective during critical illness?

PURPOSE OF REVIEW

To review the mechanisms how intermittent feeding regimens could be beneficial in critically ill patients.

RECENT FINDINGS

Large randomized controlled trials (RCTs) have failed to demonstrate consistent benefit of early, enhanced nutritional support to critically ill patients, and some trials even found potential harm. Although speculative, the absence of a clear benefit could be explained by the continuous mode of feeding in these trials, since intermittent feeding regimens had health-promoting effects in healthy animals and humans through mechanisms that also appear relevant in critical illness. Potential protective mechanisms include avoidance of the muscle-full effect and improved protein synthesis, improved insulin sensitivity, better preservation of circadian rhythm, and fasting-induced stimulation of autophagy and ketogenesis. RCTs comparing continuous versus intermittent feeding regimens in critically ill patients have shown mixed results, albeit with different design and inclusion of relatively few patients. In all studies, the fasting interval was relatively short (4-6 h maximum), which may be insufficient to develop a full fasting response and associated benefits.

SUMMARY

These findings open perspectives for the design and clinical validation of intermittent feeding regimens for critically ill patients. The optimal mode and duration of the fasting interval, if any, remain unclear.

Intermittent versus continuous enteral nutrition on feeding intolerance in critically ill adults: A meta-analysis of randomized controlled trials

OBJECTIVES

Enteral formula delivery strategy is an important part of enteral nutrition. We aimed to synthesize up-to-date studies to clarify the effects of intermittent versus continuous feeding on feeding intolerance during enteral nutrition in critically ill adults.

DESIGN

A meta-analysis of randomized controlled trials.

DATA SOURCES

Embase, PubMed, Information Sciences Institute Web of Science, CINAHL EBSCO, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure databases were searched from inception to 17th of June 2020.

REVIEW METHODS

The Cochrane "risk of bias" tool was used to assess the quality of individual studies, and the quality of each outcome was assessed by GRADE approach. Fixed or random effect meta-analysis was used pending the presence of heterogeneity. Dichotomous data synthesis was presented as risk ratio and 95% confidence interval, and quantitative data synthesis was shown as mean difference and 95% confidence interval.

RESULTS

Fourteen trials with 1025 critically ill adults were included in the meta-analysis. We found that intermittent feeding could significantly increase the occurrence of feeding intolerance (risk ratio = 1.64, 95% confidence interval = 1.23 to 2.18, P < 0.001) compared with continuous feeding, as well as the incidence of high gastric volume (risk ratio = 3.62, 95% confidence interval = 1.43-9.12, P = 0.006) and aspiration (risk ratio = 3.29, 95% confidence interval = 1.18-9.16, P = 0.02) in > 1-week trial duration, while constipation rate was reduced in intermittent feeding group (risk ratio = 0.66, 95% confidence interval = 0.45-0.98, P = 0.04). Patients in intermittent feeding group received more calories compared with continuous feeding group (mean difference = 184.81, 95% confidence interval = 56.61-313.01, P = 0.005). The quality of all evidence synthesis was "low" or "very low".

CONCLUSIONS

In critically ill adults, continuous feeding was associated with lower overall incidence of feeding intolerance, especially in high gastric volume and aspiration. However, decreased constipation incidence and more calorie intake were observed in intermittent feeding group. Because quality of the synthesized evidence was "low" or "very low", there is considerable uncertainty about this estimate.