Fasting and surgery timing (FaST) audit

Effects of the periodic fasting-mimicking diet on health, lifespan, and multiple diseases: a narrative review and clinical implications

Dietary restriction and fasting have been recognized for their beneficial effects on health and lifespan and their potential application in managing chronic metabolic diseases. However, long-term adherence to strict dietary restrictions and prolonged fasting poses challenges for most individuals and may lead to unhealthy rebound eating habits, negatively affecting overall health. As a result, a periodic fasting-mimicking diet (PFMD), involving cycles of fasting for 2 or more days while ensuring basic nutritional needs are met within a restricted caloric intake, has gained widespread acceptance. Current research indicates that a PFMD can promote stem cell regeneration, suppress inflammation, extend the health span of rodents, and improve metabolic health, among other effects. In various disease populations such as patients with diabetes, cancer, multiple sclerosis, and Alzheimer's disease, a PFMD has shown efficacy in alleviating disease symptoms and improving relevant markers. After conducting an extensive analysis of available research on the PFMD, it is evident that its advantages and potential applications are comparable to other fasting methods. Consequently, it is proposed in this review that a PFMD has the potential to fully replace water-only or very-low-energy fasting regimens and holds promise for application across multiple diseases.

Ultrasound Evaluation of Gastric Emptying and Comparison with Patient-Reported Risk Factors in Elective Surgical Patients

Background/Objectives: Despite standard preoperative fasting guidelines, residual gastric content can persist in some patients, increasing the risk of aspiration pneumonitis. Multiple patient-specific factors may predict gastric content retention, but their predictive accuracy is limited. We hypothesized that ultrasound would more reliably identify residual gastric content compared to a comprehensive questionnaire and aimed to determine the most practical approach for risk assessment in elective surgical patients. Methods: We conducted a prospective, observational study in adult patients scheduled for elective surgery at a single center. All participants adhered to an 8 h fasting period. The primary outcome was the incidence of a "full stomach" on ultrasound. Secondary outcomes included the Perlas risk classification, comparisons of established volume estimation formulas, correlations with self-reported fasting duration, agreement between questionnaire-based predictions and ultrasound findings, and the time efficiency of each method. Multivariable logistic regression and Cohen's kappa were used for analyses. Results: Data from 404 patients were analyzed. Despite prolonged fasting, 16.3% had a full stomach by ultrasound, suggesting incomplete gastric emptying. Early satiety and cholelithiasis significantly predicted a full stomach; prolonged fasting duration and female sex were protective. Questionnaire-based predictions demonstrated fair agreement with ultrasound (kappa = 0.327). The Michiko formula often yielded negative volumes, highlighting limitations in volume estimations. Ultrasound examination (3 min median) was faster than questionnaire completion (5 min). Conclusions: Ultrasound accurately detects residual gastric content, outperforming questionnaire-based assessments. Integrating it into routine preoperative evaluation may improve patient safety, although research is needed to refine volume estimation formulas and expand feasibility for patients with positioning limitations.

Fasting vs. no fasting prior to catheterization laboratory procedures: the SCOFF trial

BACKGROUND AND AIMS

Current guidelines recommend 6 h of solid food and 2 h of clear liquid fasting for patients undergoing cardiac procedures with conscious sedation. There are no data to support this practice, and previous single-centre studies support the safety of removing fasting requirements. The objective of this study was to determine the non-inferiority of a no-fasting strategy to fasting prior to cardiac catheterization procedures which require conscious sedation.

METHODS

This is a multicentre, investigator-initiated, non-inferiority, randomized trial conducted in Australia with a prospective open-label, blinded endpoint design. Patients referred for coronary angiography, percutaneous coronary intervention, or cardiac implantable electronic device (CIED)-related procedures were enrolled. Patients were randomized 1:1 to fasting as normal (6 h solid food and 2 h clear liquid) or no-fasting requirements (encouraged to have regular meals but not mandated to do so). Recruitment occurred from 2022 to 2023. The primary outcome was a composite of aspiration pneumonia, hypotension, hyperglycaemia, and hypoglycaemia assessed with a Bayesian approach. Secondary outcomes included patient satisfaction score, new ventilation requirement (non-invasive and invasive), new intensive care unit admission, 30-day readmission, 30-day mortality, 30-day pneumonia.

RESULTS

A total of 716 patients were randomized with 358 in each group. Those in the fasting arm had significantly longer solid food fasting (13.2 vs. 3.0 h, Bayes factor >100, indicating extreme evidence of difference) and clear liquid fasting times (7.0 vs. 2.4 h, Bayes factor >100). The primary composite outcome occurred in 19.1% of patients in the fasting arm and 12.0% of patients in the no-fasting arm. The estimate of the mean posterior difference in proportions with credibility interval (CI) in the primary composite outcome was -5.2% (95% CI -9.6 to -.9), favouring no fasting. This result confirms the non-inferiority (posterior probability >99.5%) and superiority (posterior probability 99.1%) of no fasting for the primary composite outcome. The no-fasting arm had improved patient satisfaction scores with a posterior mean difference of 4.02 points (95% CI 3.36-4.67, Bayes factor >100). Secondary outcome events were observed to be similar.

CONCLUSIONS

In patients undergoing cardiac catheterization and CIED-related procedures, no fasting was non-inferior and superior to fasting for the primary composite outcome of aspiration pneumonia, hypotension, hyperglycaemia, and hypoglycaemia. Patient satisfaction scores were significantly better with no fasting. This supports removing fasting requirements for patients undergoing cardiac catheterization laboratory procedures that require conscious sedation.

Design Specifications for an Automated System to Deliver Instructions About Preprocedure Fasting

PURPOSE

Many patients undergoing surgical and other medical procedures requiring sedation or anesthesia receive standardized "no eating or drinking after midnight" instructions. This "standardized" instruction does not change regardless of potential alterations in scheduling that result in significant delays in procedure start times. As a result, the duration of preprocedure fasting often far exceeds recommended requirements. A technological solution that automates the delivery of preprocedure fasting instructions to patients would likely improve the patient experience. The purpose of this study was to determine design specifications for the delivery of notifications to patients as part of an automated system.

DESIGN

A qualitative study was conducted with 14 adult participants using the persona-scenario method.

METHODS

Participants worked in groups to create realistic but fictitious personas and scenarios that described how individuals like themselves would interact with an automated preprocedure fasting instruction system. Data generated through the development of the scenarios were analyzed to first identify important themes, which were then interpreted into design specifications.

FINDINGS

Seven women and seven men, aged 25 to 75, developed 9 persona-scenarios, which captured outpatient and inpatient preprocedure fasting experiences, as well as perspectives of individuals who were not comfortable with technology, or those for which English was not the primary spoken language. Most scenarios described preprocedure fasting instructions delivered by an automated bidirectional short message service system. Two major themes were identified as patient priorities, including: (1) enhancing communication between patients and healthcare providers; and (2) the importance of using simple technology so that a greater number of patients with varying degrees of comfort and capabilities would be able to use the system confidently. A corresponding set of proposed design specifications was devised.

CONCLUSIONS

The results of this study provide actionable ways to operationalize patient-centered ideas in the design of an automated preprocedure fasting instruction system.

Comparing preoperative fasting and ultrasound-measured intravascular volume status in elective surgery, enhanced recovery patients versus inpatient, urgent surgery patients and the ability of IVC collapsibility to predict post-induction hypotension

Hypotension following induction of general anaesthesia has been shown to result in increased complications and mortality postoperatively. Patients admitted to the hospital undergoing urgent surgery are often fasted from fluids for significant periods compared to elective patients subject to Enhanced Recovery After Surgery protocols despite guidelines stating that a two-hour fast is sufficient. The aim of this prospective, observational study was to compare fasting times and intravascular volume status between elective surgery patients subject to enhanced recovery protocols and inpatient, urgent surgery patients and to assess differences in the incidence of post-induction hypotension. Fasting data was obtained by questionnaire in the preoperative area in addition to inferior vena cava collapsibility index, a non-invasive measure of intravascular volume. Blood pressure readings and drug administration for the ten minutes following induction were obtained from patients' charts. Inpatients undergoing urgent surgery were fasted significantly longer than enhanced recovery patients and had lower intravascular volume. However, no difference was found in the incidence of post-induction hypotension.

Factors influencing the fasting decisions of day-case surgery patients

BACKGROUND

Patients admitted on the day of surgery are asked to arrive fasted, and they often fast for longer than necessary. Although pre-assessment supports patients to prepare for surgery, little is known about how they make fasting decisions.

AIMS

To explore factors influencing the fasting decisions of day-case patients and how to provide information pre-operatively.

METHODS

A qualitative descriptive study design was used. Semi-structured telephone interviews were carried out with 10 patients recruited from a single day-case unit. Data were analysed using thematic analysis.

FINDINGS

Three themes provided context for fasting decisions: the operation as a serious event; the patient as an active partner; and the patient as a rule follower. Length of fast is determined by fasting decisions and practicalities.

CONCLUSION

Patients approach fasting decisions according to their knowledge and experience and their individual preferences for information. Pre-assessment nurses should tailor information to the patient and explain the rationale for fasting.

Liberal Preoperative Fasting in Adults Undergoing Elective Surgery: A Scoping Review Protocol

Background

Prolonged fasting before surgery has negative effects on the physiology and psychology of patients. Preoperative liberal fasting proposes that patients can drink clear liquids before entering the operating theater, challenging the guideline strategy of a two-hour preoperative liquid fast for adults. In recent years, there have been an increasing number of studies on liberal preoperative fasting in adults. However, currently there is no consensus on the safe amount of fluid consumed, adverse effects, or benefits of this new policy.

Objective

This scoping review protocol will map the existing evidence of liberal preoperative fasting in adults undergoing elective surgery for clinical practice, to summarize more scientific evidence to healthcare professionals when providing perioperative care. Methods and Analysis. The methodology will follow the six steps of the Arksey and O'Malley methodological framework and be guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review. A comprehensive search of six databases will be performed from their inception to 31 May 2023 to identify suitable English studies. Two trained investigators will independently screen and extract the data, and any disagreements will be judged by a third investigator. The results of the study will be presented as graphs or tables. Ethics and Dissemination. This scoping review only examines literature in the database, without reference to human or animal studies, and therefore does not require ethical approval. The findings of this scoping review will be published in peer-reviewed journals or presented at conferences. The Registration Number. This scoping review has been registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/PMW7C).

The activation impact of lactobacillus-derived extracellular vesicles on lipopolysaccharide-induced microglial cell

Perioperative neurocognitive dysfunction (PND) emerges as a common postoperative complication among elderly patients. Currently, the mechanism of PND remains unclear, but there exists a tendency to believe that inflammation plays a significant role in PND. Alterations in the abundance of intestinal microbiota can increase the permeability of the intestinal mucosal barrier and incite extraintestinal inflammatory responses. Metabolites from these microbiota can be absorbed by the intestinal mucosa into the bloodstream, exerting influence upon the central nervous system (CNS). Lactobacillus (Lac), serving as an intestinal probiotic bacterium, possesses the capacity to modulate emotional behavior and cognitive functions. Extracellular vesicles (EVs) are recognized as novel therapeutic carriers for targeted delivery to regulate physiology and pathogenesis. While the mechanism governing the primary function of Lac-EVs in the CNS remains uncertain. Therefore, we established an in vitro neuroinflammation model to induce PND and then treated the mice with Lac-EVs to observe the effect of these EVs on neuroinflammation, particularly on microglial (MG) polarization. Our research unveils that Lac-EVs reduced inflammation induced by LPS in microglia and the activation of related proteins, including the mRNA expression of M1 labeled protein (iNOS). Moreover, the mRNA expression of M2-labeled protein (Arg1) increased. In addition, flow cytometry revealed that the ratio of M1/M2 microglia also changed significantly. Therefore, Lac-EVs promoted the differentiation of M2 microglia by inducing the preferential expression of specific markers related to M2 macrophages and inflammation. In terms of inflammatory cytokine expression, Lac-EVs decreased the secretion of proinflammatory cytokines (IL-1β and IL-6) and increased IL-10 production after lipopolysaccharide (LPS) stimulation. Therefore, Lac-EVs induce the activation of M2 microglial cells without inducing cellular harm in vitro, and they demonstrate anti-inflammatory effects against lipopolysaccharide-induced neuroinflammation. This finding suggested that it is an effective anti-inflammatory strategy for alleviating inflammation-driven PNDs.

Ultrasound evaluation of gastric emptying time of standardized high-calorie liquid meals in healthy adults: A double-blind cross-over randomized study

BACKGROUND AND AIMS

Commercially available high-calorie drinks containing fat and protein can be used as dietary supplements in surgical patients. According to preoperative fasting guidelines, high-calorie drinks are non-clear fluids and should not be consumed 6 h before elective procedures. The aim of this study was to evaluate the gastric emptying time of commercially available high-calorie drink formulations in healthy adults using gastric ultrasound.

METHODS

25 healthy adult volunteers were included in this double-blind, cross-over prospective study. On three study sessions, fasted volunteers ingested one of the three study products: a solution of 75 g of glucose in 200 ml of water, a fat-free liquid meal, and a nutritionally complete liquid meal with equal volume and energy content. Gastric ultrasound examinations were performed to evaluate the gastric contents qualitatively and the volume of the gastric contents was calculated from the cross-sectional area of the gastric antrum measured in right lateral position by using a validated model. Repeated gastric ultrasounds were performed at baseline and half-hourly after ingesting the products in supine and right lateral position until the criteria for an empty stomach were met.

RESULTS

The glucose solution and the standard fat-free high-calorie drink with the same caloric content had a median gastric emptying time of 150 min. The nutritionally complete liquid meal had a median gastric emptying time of 180 min. Gastric emptying was complete in all participants before 6 h had elapsed since ingesting the study products.

CONCLUSIONS

High calorie liquid meals have a gastric emptying time longer than the recommended fasting time for clear fluids, but shorter than the recommended fasting time for solids in healthy adults.

Preoperative Patient Education: Perceptions and Actual Practice among Nurses Working in Surgical Units

Introduction

Preoperative education is an essential nursing task that can be affected by the nurses' perception. Patients may be receiving insufficient vital information before surgery. However, the essential information that should be provided to patients undergoing surgery is not fully addressed.

Objective

To assess the essential elements of preoperative information as perceived by the surgical nurses.

Methods

This was a cross-sectional study. A convenience sample of 224 registered nurses who were working at surgical units was recruited from two hospitals. A preoperative teaching questionnaire was used.

Results

Details about the operation (4.39 ± 0.61) and preoperative preparation (4.36 ± 0.61) were the most important domains of preoperative education as perceived by nurses. The results show significant differences between the perceived and actual preoperative educational practice across all domains except the preoperative preparation.

Conclusions

The delivery of preoperative education could be affected by nurses' perceptions. Efforts to facilitate the implementation of effective education as perceived by nurses should be conducted by minimizing potential barriers.

The 2023 Sir David Cuthbertson Lecture. A fluid journey: Experiments that influenced clinical practice

This review summarises some of my work on fluid and electrolyte balance over the past 25 years and shows how the studies have influenced clinical practice. Missing pieces in the jigsaw are filled in by summarising the work of others. The main theme is the biochemical, physiological and clinical problems caused by inappropriate use of saline solutions including the hyperchloraemic acidosis caused by 0.9% saline. The importance of accurate and near-zero fluid balance in clinical practice is also emphasised. Perioperative fluid and electrolyte therapy has important effects on clinical outcome in a U-shaped dose response fashion, in which excess or deficit progressively increases complications and worsens outcome. Salt and water overload, with weight gain in excess of 2.5 kg worsens surgical outcome, impairs gastrointestinal function and increases the risk of anastomotic dehiscence. Hyperchloraemic acidosis caused by overenthusiastic infusion of 0.9% saline leads to adverse outcomes and dysfunction of many organ systems, especially the kidney. Salt and water deficit causes similar adverse effects as fluid overload at the cellular level and also leads to worse outcomes. Serum albumin is shown to be affected mainly by dilution and inflammation and is not a good nutritional marker. These findings have been incorporated in the British consensus Guidelines on Intravenous Fluid Therapy for Adult Surgical Patients (GIFTASUP) and National Institute for Health and Care Excellence (NICE) guidelines on intravenous fluid therapy in adults in hospital and are helping change clinical practice and improve outcomes.

An Audit on the Pre-operative Fasting Time of Trauma-List Orthopaedic Patients at a District General Hospital in Chichester, United Kingdom

INTRODUCTION

Pre-operative fasting of patients awaiting non-emergency surgeries has been a common practice to minimise the risk of vomiting and aspiration at the time of induction of anaesthesia. Current standard guidelines recommend that this fasting time be limited to two hours for clear fluids and six hours for solids and semi-solids, as prolonged fasting has been shown to be harmful to the patient.

METHODS

A descriptive cross-sectional study of the fasting times of all adult trauma orthopaedic patients who were operated on under anaesthesia between June 1 and 30, 2023. Fifty patients who met the inclusion criteria were included in the study.

RESULTS

The minimum and maximum fasting times observed for solids and semi-solids were 9 and 24 hours, respectively. The mean fasting time for solids and semi-solids was 15.8 hours. The minimum and maximum fasting times observed for clear fluids were 2 and 20 hours, respectively. The mean fasting time for clear fluids was 10.5 hours. Elderly patients accounted for a significant portion of the patients, with 64% (n=32) being above the age of 70 years.

CONCLUSION

A significant disparity was noted between the current fasting practices and the recommended standards set out by the Royal College of Nursing, the Association of Anaesthetists of Great Britain and Ireland, the European Society of Anaesthesiology, and the American Society of Anaesthesiologists. The knowledge of pre-operative fasting among the orthopaedic team doctors and the ward nursing staff was found to be inadequate.

The Impact of Fluid Therapy on Glycemic Variation in Non-diabetic Patients Undergoing Laparoscopy

Background Hyperglycemia is a risk factor for perioperative morbidity and mortality. A surgical procedure triggers a physiological stress response, which culminates in insulin resistance by activating the sympathetic autonomic system. The impact of fluid management in the perioperative period on the glycemic variation of patients has not been thoroughly investigated. Methods This study, which included 42 non-diabetic patients undergoing laparoscopic surgeries, was an observational, prospective cohort study. The sample was split into two groups according to the type of fluid used intraoperatively: polyelectrolyte and 5% glucose polyelectrolyte. Results No significant differences were found between the groups in demographic and baseline data, including age, BMI, and American Society of Anesthesiologists (ASA) physical status. There were no differences in glycemic variation between the two groups. Blood glucose varied over time with statistical significance in the perioperative period but with no difference between the two groups. Conclusion Using 5% glucose polyelectrolyte in laparoscopic surgery for non-diabetic patients with ASA physical status 3 or lower did not significantly affect glycemic variation compared to polyelectrolyte. These results suggest the possibility of optimizing resources and minimizing waste without compromising patient homeostasis in perioperative care.

Association of a Liberal Fasting Policy of Clear Fluids Before Surgery With Fasting Duration and Patient Well-being and Safety

Importance

Current fasting guidelines for procedures under anesthesia are poorly implemented, leading to negative metabolic sequelae. Recent studies in children showed support of liberal clear fluid intake; adult physiology can support clear fluid intake, but implementation studies are lacking.

Objective

To evaluate the successfulness of implementation of a liberal clear fluid policy with regard to fasting duration, well-being, and safety in adults scheduled for anesthesia.

Design, Setting, and Participants

This was a quality improvement study conducted from January 2016 to July 2021 at a tertiary referral hospital in the Netherlands. Adults scheduled for nonemergency procedures under anesthesia were included in the study. Patients undergoing obstetrics procedures or those who were intubated preoperatively were excluded.

Interventions

Stepwise introduction of a liberal fluid fasting policy, allowing for ingestion of clear fluids until arrival at the operating room.

Main Outcomes and Measures

The primary outcome was change in fasting duration. Secondary outcomes were patient well-being, measured as preoperative thirst, amount of fluid ingested, postoperative nausea and vomiting (PONV), and administration of antiemetics. Safety was measured as incidence of regurgitation and aspiration (pneumonia).

Results

Of the 76 451 patients (mean [SD] age, 56 [17] years; 39 530 male individuals [52%] 36 921) included in the study, 59 036 (78%) followed the standard policy, and 16 815 (22%) followed the liberal policy. Time series analysis showed an estimated fasting duration decrease of 3:07 hours (IQR, 1:36-7:22; P < .001) after implementation of the liberal policy. Postimplementation median (IQR) fasting duration was 1:20 (0:48-2:24) hours. The incidence of regurgitation changed from 18 (95% CI, 14-21) to 24 (95% CI, 17-32) in 10 000 patients, and the incidence of aspiration changed from 1.7 (95% CI, 0.6-2.7) to 2.4 (95% CI, 0.5-4.7) in 10 000 patients. In the liberal policy, thirst feelings decreased (37% [4982 of 8615] vs 46% [3373 of 7362]; P < .001). PONV incidence decreased from 10.6% (6339 of 59 636) to 9.4% (1587 of 16 815; P < .001) and antiemetic administration decreased from 11.0% (6538 of 59 636) to 9.5% (1592 of 16 815; P < .001).

Conclusions and Relevance

Results of this quality improvement study suggest that a liberal fasting policy was associated with a clinically relevant reduction in fasting duration and improved patient well-being with regard to preoperative thirst and PONV. Although a slightly higher incidence of regurgitation could not be ruled out, wider implementation of such a policy may be advocated as results are still within the clinically accepted risks margins. Results suggest that surgical procedures in patients who drink clear fluids within 2 hours before anticipated anesthesia should not be postponed or canceled.

Real-World Evidence: How Long Do Our Patients Fast?-Results from a Prospective JAGO-NOGGO-Multicenter Analysis on Perioperative Fasting in 924 Patients with Malignant and Benign Gynecological Diseases

BACKGROUND

Despite the key role of optimized fasting in modern perioperative patient management, little current data exist on perioperative fasting intervals in routine clinical practice.

METHODS

In this multicenter prospective study, the length of pre- and postoperative fasting intervals was assessed with the use of a specifically developed questionnaire. Between 15 January 2021 and 31 May 2022, 924 gynecology patients were included, from 13 German gynecology departments.

RESULTS

On average, patients remained fasting for about three times as long as recommended for solid foods (17:02 ± 06:54 h) and about five times as long as recommended for clear fluids (9:21 ± 5:48 h). The average perioperative fasting interval exceeded one day (28:23 ± 14:02 h). Longer fasting intervals were observed before and after oncological or extensive procedures, while shorter preoperative fasting intervals were reported in the participating university hospitals. Smoking, treatment in a non-university hospital, an increased Charlson Comorbidity Index and extensive surgery were significant predictors of longer preoperative fasting from solid foods. In general, prolonged preoperative fasting was tolerated well and quality of patient information was perceived as good.

CONCLUSION

Perioperative fasting intervals were drastically prolonged in this cohort of 924 gynecology patients. Our data indicate the need for better patient education about perioperative fasting.

Preoperative fasting: exploring guidelines and evidence to ensure consistent, high-quality care

Many nurses will still be familiar with the instruction 'nil by mouth from midnight' traditionally given to patients preparing to undergo surgery. National and international guidelines now promote much shorter preoperative fasting times, encapsulated in the '2-4-6 rule' - two hours for clear fluids, four hours for breast milk and six hours for solids. The latest evidence appears to show that these fasting times are in need of revision. Furthermore, there are inconsistencies in how guidelines are implemented. This article explores the guidelines and literature on preoperative fasting in adults and children to determine what the evidence is and what changes could be made to ensure consistent, high-quality patient care.

Patient Education Regarding Fasting Recommendations to Shorten Fasting Times in Patients Undergoing Esophagogastroduodenoscopy: A Controlled Pilot Study

This study evaluated the applicability and efficacy of patient education regarding fasting recommendations to shorten fasting times in patients undergoing esophagogastroduodenoscopy (EGD). A prospective nonrandomized controlled pilot study was performed. The intervention group (IG) was educated by nurses to eat until 6 hours and drink until 2 hours before EGD. The control group (CG) received usual care. Outcomes were applicability as perceived by patients, adherence to fasting recommendations, gastric visibility, and patients' comfort. A total of 109 patients were included of whom 42 were IG patients (37%). Patients' perspectives on fasting, their experienced discomfort, professional support, and circadian rhythm influenced application of fasting recommendations. Adherence to length of fasting from foods improved with 3:14 hours ( p < .001) and from liquids with 5:22 hours ( p < .001) in the IG compared with the CG. Gastric visibility during EGD was better in the IG than in the CG. The IG patients experienced significant less thirst, hunger, headache, and anxiety. To successfully reduce fasting times, fasting education should include positive, individual instructions, which help patients apply the fasting recommendations within their biorhythm. Positive, concrete instructions by nurses shortened fasting times before EGD, which improved gastric visibility and reduced patient discomfort.

Effects of Preoperative Oral Electrolyte-Carbohydrate Nutrition Supplement on Postoperative Outcomes in Elderly Patients Receiving Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

Objective

Patients undergoing total knee arthroplasty (TKA) were primarily geriatric, with high risk of postoperative electrolyte disorders and malnutrition. Randomized controlled trials regarding oral nutrition supplement (ONS) strategies in TKA was sparse. This study aimed to evaluate the efficacy of preoperative oral electrolyte‐carbohydrate nutrition supplement (OECNS) on patients (aged >65 years) undergoing TKA.

Methods

From April 2019 to January 2020, 94 patients undergoing primary elective unilateral TKA in our hospital were considered in this prospective randomized controlled study. This study included patients aged over 65 years with ASA I‐III, and excluded patients with electrolyte disorders, malnutrition, and comorbidities. The control group (control group) received meal nutrition supplements (preoperative 6 h [Pre 6h]) and water (Pre 2h), while OECNS group (intervention group) received meal nutrition supplements (Pre 6h) and OECNS (Pre 2). The Student's t test and χ² test was used. The primary outcomes were the patient‐reported comfort indicators (PRCIs) including hunger, thirst, nausea, vomiting, weakness, pain, anxiety, and general comfort. The secondary outcomes included indicators of electrolyte, nutrition, functional scores, clinical results, and complications.

Results

The scores of preoperative hunger (0.43 ± 0.10), pain (2.30 ± 0.34), and anxiety (9.04 ± 2.71) were significantly lower in OECNS group compared with control group (hunger, 1.19 ± 0.21; pain, 3.79 ± 0.26; anxiety, 11.21 ± 3.02) (Pre 1h) (all p < 0.05) as well as the weakness score on the first postoperative day (POD1) (OECNS group 3.57 ± 0.24; control group 5.15 ± 0.29; p < 0.001). A higher level of Na + (OECNS group 140.54 ± 3.39; control group 138.07 ± 5.21; p = 0.008) and a reduced rate of hyponatremia (OECNS group 6.4%; control group 21.3%; p = 0.036) on POD1 were found. Moreover, the higher level of blood glucose (Post 2h) and reduced rates of abnormal blood glucose (Pre 2h, Post 6h) were verified in control group (all p < 0.05). There was no significant difference regarding the other outcomes.

Conclusion

The administration of OECNS significantly improved subjective comfort, electrolytes, and blood glucose without increasing the rates of complications in patients (aged over 65 years) undergoing TKA.

The effects of elective abdominal surgery on protein turnover: A meta-analysis of stable isotope techniques to investigate postoperative catabolism

BACKGROUND & AIMS

Elective surgery induces skeletal muscle wasting driven by an imbalance between muscle protein synthesis and breakdown. From examination of diverse stable isotope tracer techniques, the dynamic processes driving this imbalance are unclear. This meta-analysis aimed to elucidate the mechanistic driver(s) of postoperative protein catabolism through stable isotope assessment of protein turnover before and after abdominal surgery.

METHODS

Meta-analysis was performed of randomized controlled trials and cohort studies in patients undergoing elective abdominal surgery that contained measurements of whole-body or skeletal muscle protein turnover using stable isotope tracer methodologies pre- and postoperatively. Postoperative changes in protein synthesis and breakdown were assessed through subgroup analysis of tracer methodology and perioperative care.

RESULTS

Surgery elicited no overall change in protein synthesis [standardized mean difference (SMD) -0.47, 95% confidence interval (CI): -1.32, 0.39, p = 0.25]. However, subgroup analysis revealed significant suppressions via direct-incorporation methodology [SMD -1.53, 95%CI: -2.89, -0.17, p = 0.03] within skeletal muscle. Changes of this nature were not present among arterio-venous [SMD 0.61, 95%CI: -1.48, 2.70, p = 0.58] or end-product [SMD -0.09, 95%CI: -0.81, 0.64, p = 0.82] whole-body measures. Surgery resulted in no overall change in protein breakdown [SMD 0.63, 95%CI: -0.06, 1.32, p = 0.07]. Yet, separation by tracer methodology illustrated significant increases in urinary end-products (urea/ammonia) [SMD 0.70, 95%CI: 0.38, 1.02, p < 0.001] that were not present among arterio-venous measures [SMD 0.67, 95%CI: -1.05, 2.38, p = 0.45].

CONCLUSIONS

Elective abdominal surgery elicits suppressions in skeletal muscle protein synthesis that are not reflected on a whole-body level. Lack of uniform changes across whole-body tracer techniques are likely due to contribution from tissues other than skeletal muscle.

Effect of Carbohydrate-Enriched Drink Compared to Fasting on Hemodynamics in Healthy Volunteers. A Randomized Trial

Fasting prior to surgery can cause dehydration and alter hemodynamics. This study aimed to determine the impact of a carbohydrate-enriched drink (NutriciaTM Pre-op®) on selected hemodynamical parameters, measured in a non-invasive manner. We enrolled 100 healthy volunteers and measured their weight, height, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), thoracic fluid content (TFC), thoracic fluid index (TFCI), stroke volume (SV), stroke volume variation (SVV), stroke index (SI), cardiac output (CO), cardiac index (CI), heather index (HI), systolic time ration (STR), systemic time ratio index (STRI), systemic vascular resistance (SVR), and systemic vascular resistance index (SVRI) by a Niccomo™ device, implementing the impedance cardiography (ICG) method. Measurements were performed at the beginning of the study, and after 10 h and 12 h. We randomly allocated participants to the control group and the pre-op group. The pre-op group received 400 mL of Nutricia™ preOp®, as suggested in the ERAS guidelines, within 10 h of the study. Student's t-test or the Mann-Whitney U test were used to compare the two groups, and p < 0.05 was considered significant. We did not observe any changes in hemodynamical parameters, blood pressure, and heart rate between the groups. We have proven that carbohydrate-enriched drink administration did not have a significant impact on the hemodynamical parameters of healthy volunteers.