Early oral protein-containing diets following elective lower gastrointestinal tract surgery in adults: a meta-analysis of randomized clinical trials

Background

Although current guidelines make consensus recommendations for the early resumption of oral intake after surgery, a recent comprehensive meta-analysis failed to identify any patient-centered benefits. We hypothesized this finding was attributable to pooling studies providing effective protein-containing diets with ineffective non-protein liquid diets. Therefore, the aim of this paper was to investigate the safety and efficacy of early oral protein-containing diets versus later (traditional) feeding after elective lower gastrointestinal tract surgery in adults.

Methods

PubMed, Embase, and the China National Knowledge Infrastructure databases were searched from inception until 1 August 2019. Reference lists of retrieved studies were hand searched to identify randomized clinical trials reporting mortality. No language restrictions were applied. Study selection, risk of bias appraisal and data abstraction were undertaken independently by two authors. Disagreements were settled by obtaining an opinion of a third author. Majority decisions prevailed. After assessment of underlying assumptions, a fixed-effects method was used for analysis. The primary outcome was mortality. Secondary outcomes included surgical site infections, postoperative nausea and vomiting, serious postoperative complications and other key measures of safety and efficacy.

Results

Eight randomized clinical trials recruiting 657 patients were included. Compared with later (traditional) feeding, commencing an early oral protein-containing diet resulted in a statistically significant reduction in mortality (odds ratio [OR] 0.31, P = 0.02, I² = 0%). An early oral protein-containing diet also significantly reduced surgical site infections (OR 0.39, P = 0.002, I² = 32%), postoperative nausea and vomiting (OR 0.62, P = 0.04, I² = 37%), serious postoperative complications (OR 0.60, P = 0.01, I² = 25%), and significantly improved other major outcomes. No harms attributable to an early oral protein-containing diet were identified.

Conclusions

The results of this systematic review can be used to upgrade current guideline statements to a grade A recommendation supporting an oral protein-containing diet commenced before the end of postoperative day 1 after elective lower gastrointestinal surgery in adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-021-00179-3.

Intravenous amino acid therapy for kidney function in critically ill patients: a randomized controlled trial

IMPORTANCE

Acute kidney injury (AKI) is characterized by severe loss of glomerular filtration rate (GFR) and is associated with a prolonged intensive care unit (ICU) stay and increased risk of death. No interventions have yet been shown to prevent AKI or preserve GFR in critically ill patients. Evidence from mammalian physiology and small clinical trials suggests higher amino acid intake may protect the kidney from ischemic insults and thus may preserve GFR during critical illness.

OBJECTIVE

To determine whether amino acid therapy, achieved through daily intravenous (IV) supplementation with standard amino acids, preserves kidney function in critically ill patients.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, phase II, randomized clinical trial conducted between December 2010 and February 2013 in the ICUs of 16 community and tertiary hospitals in Australia and New Zealand. Participants were adult critically ill patients expected to remain in the study ICU for longer than 2 days.

INTERVENTIONS

Random allocation to receive a daily supplement of up to 100 g of IV amino acids or standard care.

MAIN OUTCOMES AND MEASURES

Duration of renal dysfunction (primary outcome); estimated GFR (eGFR) derived from creatinine; eGFR derived from cystatin C; urinary output; renal replacement therapy (RRT) use; fluid balance and other measures of renal function.

RESULTS

474 patients were enrolled and randomized (235 to standard care, 239 to IV amino acid therapy). At time of enrollment, patients allocated to receive amino acid therapy had higher APACHE II scores (20.2 ± 6.8 vs. 21.7 ± 7.6, P = 0.02) and more patients had pre-existing renal dysfunction (29/235 vs. 44/239, P = 0.07). Duration of renal dysfunction after enrollment did not differ between groups (mean difference 0.21 AKI days per 10 patient ICU days, 95 % CI -0.27 to 1.04, P = 0.45). Amino acid therapy significantly improved eGFR (treatment group × time interaction, P = 0.004), with an early peak difference of 7.7 mL/min/1.73 m(2) (95 % CI 1.0-14.5 mL/min/1.73 m(2), P = 0.02) on study day 4. Daily urine output was also significantly increased (+300 mL/day, 95 % CI 145-455 mL, P = 0.0002). There was a trend towards increased RRT use in patients receiving amino acid therapy (13/235 vs. 25/239, P = 0.062); however, this trend was not present after controlling for baseline imbalance (P = 0.21).

CONCLUSION AND RELEVANCE

Treatment with a daily IV supplement of standard amino acids did not alter our primary outcome, duration of renal dysfunction.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12609001015235.

Intensive care specialists' knowledge, attitudes, and professional use of published research evidence: a mail-out questionnaire survey of appropriate use of research evidence in clinical practice

PURPOSE

This survey investigates the knowledge, attitudes, and use of published research in clinical practice by intensive care specialists.

MATERIALS AND METHODS

A mail-out questionnaire was sent to randomly selected intensive care specialists registered with the Australian and New Zealand College of Intensive Care Medicine.

RESULTS

The response rate was 55.9% (133/238). The average score for research knowledge was 2.9 of 6. Eighty-five (65.4%) of 130 respondents reported positive feelings toward using published research evidence in clinical practice, with 96.6% (126/130) reporting use of the concepts of evidence-based medicine at least sometimes. Randomized trials were rated as the most frequently read evidence (rank score, 3.7 of 5), with "Information obtained from the Cochrane Library" the least frequently read (rank score, 2.8 of 5). The most inhibiting barrier to use of published research evidence in practice was "a lack of good evidence providing meaningful answers to clinical problems" (rank score, 3.5 of 5). Eighty-eight (67.7%) of 130 respondents appropriately used published research evidence in clinical practice.

CONCLUSIONS

Respondents reported generally positive attitudes toward using published research evidence, in clinical practice; however, room for improvement in technical knowledge relating to published research evidence was noted.

Early parenteral nutrition in critically ill patients with short-term relative contraindications to early enteral nutrition: a randomized controlled trial

IMPORTANCE

Systematic reviews suggest adult patients in intensive care units (ICUs) with relative contraindications to early enteral nutrition (EN) may benefit from parenteral nutrition (PN) provided within 24 hours of ICU admission.

OBJECTIVE

To determine whether providing early PN to critically ill adults with relative contraindications to early EN alters outcomes.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, randomized, single-blind clinical trial conducted between October 2006 and June 2011 in ICUs of 31 community and tertiary hospitals in Australia and New Zealand. Participants were critically ill adults with relative contraindications to early EN who were expected to remain in the ICU longer than 2 days.

INTERVENTIONS

Random allocation to pragmatic standard care or early PN.

MAIN OUTCOMES AND MEASURES

Day-60 mortality; quality of life, infections, and body composition.

RESULTS

A total of 1372 patients were randomized (686 to standard care, 686 to early PN). Of 682 patients receiving standard care, 199 patients (29.2%) initially commenced EN, 186 patients (27.3%) initially commenced PN, and 278 patients (40.8%) remained unfed. Time to EN or PN in patients receiving standard care was 2.8 days (95% CI, 2.3 to 3.4). Patients receiving early PN commenced PN a mean of 44 minutes after enrollment (95% CI, 36 to 55). Day-60 mortality did not differ significantly (22.8% for standard care vs 21.5% for early PN; risk difference, -1.26%; 95% CI, -6.6 to 4.1; P = .60). Early PN patients rated day-60 quality of life (RAND-36 General Health Status) statistically, but not clinically meaningfully, higher (45.5 for standard care vs 49.8 for early PN; mean difference, 4.3; 95% CI, 0.95 to 7.58; P = .01). Early PN patients required fewer days of invasive ventilation (7.73 vs 7.26 days per 10 patient × ICU days, risk difference, -0.47; 95% CI, -0.82 to -0.11; P = .01) and, based on Subjective Global Assessment, experienced less muscle wasting (0.43 vs 0.27 score increase per week; mean difference, -0.16; 95% CI, -0.28 to -0.038; P = .01) and fat loss (0.44 vs 0.31 score increase per week; mean difference, -0.13; 95% CI, -0.25 to -0.01; P = .04).

CONCLUSIONS AND RELEVANCE

The provision of early PN to critically ill adults with relative contraindications to early EN, compared with standard care, did not result in a difference in day-60 mortality. The early PN strategy resulted in significantly fewer days of invasive ventilation but not significantly shorter ICU or hospital stays.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN012605000704695.

Early enteral nutrition reduces mortality in trauma patients requiring intensive care: a meta-analysis of randomised controlled trials

INTRODUCTION

To determine whether the provision of early standard enteral nutrition (EN) confers treatment benefits to adult trauma patients who require intensive care.

MATERIALS AND METHODS

MEDLINE and EMBASE were searched. Hand citation review of retrieved guidelines and systematic reviews was undertaken and academic and industry experts were contacted. Methodologically sound randomised controlled trials (RCTs) conducted in adult trauma patients requiring intensive care that compared the delivery of standard EN, provided within 24 h of injury, to standard care were included.The primary analysis was conducted on clinically meaningful patient-oriented outcomes, which included mortality, functional status and quality of life. Secondary analyses considered vomiting/regurgitation, pneumonia, bacteraemia, sepsis and multiple organ dysfunction syndrome. Meta-analysis was conducted using an analytical method known to minimise bias in the presence of sparse events. The impact of heterogeneity was assessed using the I2 metric.

RESULTS

Three RCTs with 126 participants were found to be free from major flaws and were included in the primary analysis. The provision of early EN was associated with a significant reduction in mortality(OR = 0.20, 95% confidence interval 0.04–0.91, I2 = 0). No other outcomes could be pooled. A sensitivity analysis and a confirmatory analysis conducted using a different analytical method confirmed the presence of a mortality reduction.

CONCLUSION

Although the detection of a statistically significant reduction in mortality is promising,overall trial quality was low and trial size was small. The results of this meta-analysis should be confirmed by the conduct of a large multi-center trial.

An overview of evidence from systematic reviews evaluating early enteral nutrition in critically ill patients: more convincing evidence is needed

International quality improvement initiatives such as Fast-Hug bring a focus on improving the delivery of early enteral nutrition to critically ill patients, however surveys demonstrate current practice remains variable. One way to reduce variability in practice is to provide strong evidence to convince clinicians to change. The purpose of this overview was to identify current best evidence supporting the delivery of early enteral nutrition in critical illness. We sought high-quality evidence in the form of systematic reviews containing meta-analyses of randomised controlled trials. Two authors independently identified studies and assessed methodological quality. Data sources included Medline, EMBASE and hand-searching of guideline reference lists. The literature search identified five systematic reviews that summarised 30 clinical trials. These systematic reviews focused on acutely hospitalised patients, critical illness, burns, elective intestinal surgery and pancreatitis. Early enteral nutrition significantly reduced mortality in elective intestinal surgery patients (relative risk 0.41, 95% confidence interval 0.18 to 0.93, P = 0.03, I2 = 0.0%) and significantly reduced infectious complications in acutely ill hospitalised patients (relative risk 0.45, 95% confidence interval 0.3 to 0.66, P = 0.00006, heterogeneity P = 0.049). Four of five identified systematic reviews had key methodological quality deficiencies. The results of this overview highlight the variability in the evidence regarding the benefits of early enteral nutrition in critically ill patient populations. The inconsistent delivery to critically ill patients may be explained by the lack of convincing evidence. Better evidence may be needed to reduce the irregularity in the provision of early enteral nutrition to critically ill patients.

Early enteral nutrition, provided within 24 h of injury or intensive care unit admission, significantly reduces mortality in critically ill patients: a meta-analysis of randomised controlled trials

PURPOSE

To determine whether the provision of early standard enteral nutrition (EN) confers treatment benefits to critically ill patients.

METHODS

Medline and EMBASE were searched. Hand citation review of retrieved guidelines and systematic reviews were undertaken, and academic and industry experts were contacted. Methodologically sound randomised controlled trials (RCTs) conducted in critically ill patient populations that compared the delivery of standard EN, provided within 24 h of intensive care unit (ICU) admission or injury, to standard care were included. The primary analysis was conducted on clinically meaningful patient-oriented outcomes. Secondary analyses considered vomiting/regurgitation, pneumonia, bacteraemia, sepsis and multiple organ dysfunction syndrome. Meta-analyses were conducted using the odds ratio (OR) metric and a fixed effects model. The impact of heterogeneity was assessed using the I (2) metric.

RESULTS

Six RCTs with 234 participants were analysed. The provision of early EN was associated with a significant reduction in mortality [OR = 0.34, 95% confidence interval (CI) 0.14-0.85] and pneumonia (OR = 0.31, 95% CI 0.12-0.78). There were no other significant differences in outcomes. A sensitivity analysis and a simulation exercise confirmed the presence of a mortality reduction.

CONCLUSION

Although the detection of a statistically significant reduction in mortality is promising, overall trial quality was low, trial size was small, and the findings may be restricted to the patient groups enrolled into included trials. The results of this meta-analysis should be confirmed by the conduct of a large multi-centre trial enrolling diverse critically ill patient groups.