Preoperative Fluid Fasting Times and Postinduction Low Blood Pressure in Children

Effects of Ciprofol and Propofol General Anesthesia on Postoperative Recovery Quality in Patients Undergoing Ureteroscopy: A Randomized, Controlled, Double-Blind Clinical Trial

Objective

This study compares postoperative recovery quality between Ciprofol and Propofol, providing a reference for the clinical application of anesthetics.

Methods

We randomized 112 patients undergoing ureteroscopic surgery into two groups: the Ciprofol group (Group C), with an induction dose of 0.4 mg/kg and a maintenance dose of 0.8-1.5 mg/(kg·h), and the Propofol group (Group P), with an induction dose of 2 mg/kg and a maintenance dose of 4-10 mg/(kg·h). Both groups received sevoflurane at a concentration of 1%. The Bispectral Index (BIS) was maintained between 40 and 60. The primary outcomes were the Quality of Recovery-15 (QoR-15) scores on postoperative day 1 (POD1). Secondary outcomes included hemodynamic parameters, vasopressor use, timing indicators, sedative consumption, BIS values, Riker Sedation-Agitation Scale (R-SAS) scores, urinary tract symptoms, patient satisfaction, and adverse events.

Results

No significant differences were observed in QoR-15 scores between the two groups. Although Group C had higher pain (P = 0.004) and comfort (P = 0.002) scores on POD1, these differences were not clinically significant. The incidence of hypotension and vasopressor use was lower in Group C, which had more stable hemodynamics. Additionally, the time from induction to BIS ≤ 60 was shorter in Group P (P = 0.001), while Group C had lower BIS values from drug discontinuation to full recovery of consciousness (P = 0.001). The incidence of urinary tract symptoms on POD1 was lower in Group C (P = 0.043). There were no significant differences in time to spontaneous breathing recovery, extubation, recovery room stay, time to first ambulation, hospital stay, patient satisfaction, or other adverse events.

Conclusion

Ciprofol provides comparable early postoperative recovery to Propofol during ureteroscopy and may be a preferable alternative for urological procedures, especially in patients with blood pressure concerns.

Trial Registration

Chinese Clinical Trial Registry (ChiCTR2400082736).

Pharmacogenetic and pharmacokinetic factors for dexmedetomidine-associated hemodynamic instability in pediatric patients

Purpose

The incidence of hemodynamic instability associated with dexmedetomidine (DEX) sedation has been reported to exceed 50%, with substantial inter-individual variability in response. Genetic factors have been suggested to contribute significantly to such variation. The aim of this study was to identify the clinical, pharmacokinetic, and genetic factors associated with DEX-induced hemodynamic instability in pediatric anesthesia patients.

Methods

A cohort of 270 pediatric patients scheduled for elective interventional surgery received an intranasal dose of 3 mcg·kg-1 of dexmedetomidine, and subsequent propofol induction was conducted when patients had a UMSS of 2-4. The primary endpoint was hemodynamic instability-defined as a composite of hypotension and/or bradycardia, which is characterized by a 20% reduction from age-specific baseline values. Plasma concentrations of dexmedetomidine were determined, and single-nucleotide polymorphisms (SNPs) were genotyped. A validated population pharmacokinetic model was used to estimate pharmacokinetic parameters. LASSO regression was used to identify significant factors, and a Cox's proportional hazards model-derived nomogram for hemodynamic instability was developed.

Results

Hemodynamic instability was observed in 52 out of 270 patients (209 events), resulting in a cumulative incidence of 16.30% at 90 min, as estimated by Kaplan-Meier estimation, and it was associated with a median time to event of 35 min. The interval time between DEX initiation and propofol induction was 16 min (IQR: 12-22 min). The cumulative incidence was 8.2% within 22 min after DEX initiation. The identified significant risk factors for DEX-associated hemodynamic instability included weight, DEX clearance, concomitant propofol use, and the following gene variants UGT2B10 rs1841042 (hazard ratio (HR):1.41, 95% confidence interval (CI): 1.12-1.79), CYP2A6 rs8192733 (HR:0.28, 95%CI:0.09-0.88), ADRA2B rs3813662 (HR:1.39,95%CI:1.02-1.89), CACNA2D2 rs2236957 (HR:1.46, 95%CI:1.09-1.96), NR1I2 rs3814057 (HR:0.64, 95%CI:0.43-0.95), and CACNB2 rs10764319 (HR:1.40,95%CI:1.05-1.87). The areas under the curve for the training and test cohorts were 0.881 and 0.762, respectively. The calibration curve indicated excellent agreement.

Conclusion

The predictive nomogram, which incorporates genetic variants (UGT2B10, CYP2A6, ADRA2B, CACNA2D2, NR1I2, and CACNB2) along with clinical factors such as weight, DEX clearance, and propofol use, may help prevent DEX-associated hemodynamic instability. Delayed hemodynamic instability is likely to occur after 35-min DEX initiation in patients with lower DEX clearance after propofol induction.

Gastric ultrasound assessment of two preoperative fasting regimens in pediatric patients: A randomized clinical trial

BACKGROUND

Preoperative fasting aims to reduce the risk of pulmonary aspiration. Our aim was to compare the incidence of increased gastric content after preoperative liberal versus a standard fasting in children.

METHOD

Two hundred children, presented for elective surgeries, were instructed to follow either 6-4-2 (standard group) or 6-4-0 (liberal group) preoperative fasting regimens. Preoperative ultrasound was used to evaluate gastric contents. The primary outcome was the proportion of patients with an "at-risk stomach." Secondary outcomes included qualitative and quantitative gastric assessment, last meal, actual fasting duration, regurgitation, vomiting, aspiration incidence, surgery cancellation rate, and complications of prolonged fasting (e.g., hunger).

RESULTS

The actual fasting duration was significantly longer than prescribed in each group (p < 0.001 for both groups) and was significantly longer in the standard group (CI95%: 0.744-2.016, medium effect size η2 = 0.068). In the liberal group, 3% of patients had an "at-risk stomach," and 2% of cases were canceled. Qualitative gastric assessment was comparable between the two groups (OR 1.536, CI95%: 0.883-2.670, low effect size Cramer V = 0.139). However, the estimated gastric volume/weight ratio was significantly increased in the standard group (CI95%: 0.114-0.214; large effect size η2 = 0.171). In the standard group, 9% of patients were hungry, and 10% were thirsty; no patients experienced adverse effects in either group.

CONCLUSION

Prolonged preoperative fasting may be unnecessary. The 6-4-0 fasting regimen can be applied to pediatric patients before elective surgeries without increasing the incidence of "at risk stomach," but further studies with larger sample size are needed to confirm these results.

TRIAL REGISTRATION

ClinicalTrials.gov (Trial no.: NCT04961814).

Effect of Preoperative Gum Chewing on Postoperative Nausea and Vomiting in Women Undergoing Robotic Laparoscopic Surgery for Uterine Myomas: A Randomized Controlled Trial

BACKGROUND

Postoperative nausea and vomiting (PONV) remains a frequent and uncomfortable complication in women undergoing robotic gynecological procedures. Despite the use of various preventive strategies, PONV continues to negatively impact recovery and increase healthcare expenses. This study aimed to evaluate whether the preoperative use of sugar-free chewing gum could effectively minimize the dependence on anti-emetic drugs in women undergoing robot-assisted laparoscopic surgery for uterine myomas.

METHODS

In this randomized, single-blind study, 92 adult women scheduled for robot-assisted laparoscopic surgery were enrolled. The participants were randomly assigned to one of two groups: a gum-chewing group, which was instructed to chew sugar-free gum for 15 min in the preoperative holding area, or a control group that did not chew gum. The primary outcome was the requirement for anti-emetic medication within the first hour after surgery, when the patient was in the post-anesthesia care unit (PACU). Secondary outcomes included the overall frequency of anti-emetic use. To assess the intervention's effectiveness independent of any other factors, no prophylactic anti-emetics were administered during surgery.

RESULTS

Of the 92 participants, 89 completed the study, with 44 assigned to the gum-chewing group and 45 to the control group. The gum-chewing group showed a significantly lower rate of PONV, requiring anti-emetic treatment (79.5%), compared to the control group (95.6%). Additionally, the control group demonstrated a higher overall need for anti-emetic medications. Notably, there were no reported adverse effects, such as jaw discomfort, dental injuries, or gastric regurgitation, in either group.

CONCLUSIONS

Chewing sugar-free gum for 15 min prior to surgery was found to be a safe, simple, and effective method to reduce the occurrence of PONV in women undergoing robot-assisted laparoscopic surgery for benign uterine tumors. This non-invasive intervention reduced the reliance on anti-emetic drugs and improved patient comfort, without introducing risks. These findings suggest that preoperative gum chewing could be routinely implemented in clinical settings to enhance surgical outcomes.

Reviewing "Nil Per Os" Guidance for Clear Fluids in Children Before Anesthesia: Survey of the Pediatric Anesthesia Leadership Council

BACKGROUND

Several international pediatric anesthesia societies have endorsed a change in the traditional nil per os (NPO) cutoff of clear fluids (CF) from 2 hours to 1 hour. These recommendations were compiled from large-scale outcomes, gastric ultrasound, and quality improvement studies. The American Society of Anesthesiologists (ASA) recently published their updated guidelines. Despite the lack of prospective randomized studies with conclusive outcomes, several major children's health systems in North America have already implemented or are modifying their institutional guidelines for CF. The objectives of this survey were to evaluate the current practices, changing trends, perceived benefits, and barriers in reducing the NPO times for CF in children presenting for anesthesia.

METHODS

After approval from the Penn State University Institutional Review Board, an electronic survey of the Pediatric Anesthesia Leadership Council (PALC, consortium of Pediatric Anesthesiology Chairs and Division Chiefs across the United States) members was conducted by the Society for Pediatric Anesthesia Quality and Safety Committee (SPA-QS) NPO Clears Task Force between June 2023 and October 2023. Inclusion criteria were PALC membership and single response from each institution.

RESULTS

A total of 88 member institutions were represented by the PALC group. The final response rate was 75 of 88 (85.2%) from across 33 states. Eighty-eight percent of the respondents belonged to a tertiary pediatric center, and 94.7% belonged to an academic setting. At the time of the survey, 8 out of 75 (10.6%) responding institutions followed 1-hour CF cutoff, 7 (9.3%) were in the process of changing to 1-hour and 60 (80%) followed a 2-hour cutoff. 55(73%) respondents actively encouraged CF up to the time they had to be NPO. 46.7% of the respondents reported significant issues (hypoglycemia, dehydration, difficulty in establishing intravenous access, patient and parental dissatisfaction) with prolonged fasting in children. The survey responses included multiple comments in favor of changing guidelines to 1 hour for CF in healthy young children. The overarching concern for implementation of 1-hour cutoff for CF was the potential medicolegal ramification of a policy change in the absence of an official statement from national professional societies.

CONCLUSIONS

The survey demonstrates growing trends toward implementing the reduced NPO time for CF to 1 hour nationally. Based on the current ASA guidelines, the SPA-QS committee recommends close attention to NPO times and strongly encourages CF consumption up to the recommended cutoff time. It appears reasonable to follow a 1-hour cutoff for CF as deemed appropriate by the attending anesthesiologist or the institution.

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.

Adherence to Preoperative Fasting Guidelines in Elective Surgical Patients

INTRODUCTION

Preoperative fasting is recommended by international guidelines as a means to minimize the risk of aspiration of gastric content during induction of anesthesia or surgery. Prolonged preoperative fasting is, however, discouraged due to the associated side effects such as dehydration and electrolyte imbalance, which can negatively impact recovery after surgery. An initial quality improvement study revealed poor implementation of the best practice guidelines on preoperative fasting in three departments of a hospital and an institutional action plan was devised to enforce adherence to these guidelines. This present study aimed to assess compliance with the action plan and for that matter, adherence to international consensus on preoperative fasting in three surgical departments.

METHODS

Adult patients undergoing elective cardiac, thoracic, and vascular surgery at a university teaching hospital were surveyed over four months (September October, November, and December of 2023). Data on the length of preoperative fasting was collected using a standardized questionnaire. A total of 306 patients who were scheduled for elective surgery were included in the study.

RESULTS

Of the 306 patients, 139 (45.4%) had vascular surgeries, 108 (35.4%) received cardiac surgeries, and 59 (19.3%) had thoracic surgeries. For clear fluids, the overall median fasting time (Q1, Q3) was 4.5 (2.7, 7.4) hours, and for solid food, 14.5 (12.1, 19.0) hours. Extended abstinence from clear fluids and solid food for more than 12 hours was observed in 43 (14.1%) and 231 (75.5%) instances, respectively, while abstinence from solid food for more than 24 hours was noticed in 40 (13.1%) cases. When compared to patients having operations in the morning, those scheduled for afternoon surgery had longer median fasting periods from clear fluids and solid food, p<0.001: 6.2 (4.0, 12.0) hours vs. 3.4 (2.0, 5.2) hours for clear fluids and 16.7 (12.6, 22.6) hours vs. 13.2 (9.6, 15.2) hours for solid food, respectively.

CONCLUSION

Patients continue to abstain from clear fluids and solid food for extended periods of time, despite the fact that there is worldwide agreement regarding shorter periods of preoperative fasting. Compared to patients undergoing morning surgery, individuals hospitalized for afternoon procedures were more likely to fast for extended periods of time.

Prevention of hypotension after induction of general anesthesia using point-of-care ultrasound to guide fluid management: a randomized controlled trial

PURPOSE

Hypotension after induction of general anesthesia (GAIH) is common and is associated with postoperative complications including increased mortality. Collapsibility of the inferior vena cava (IVC) has good performance in predicting GAIH; however, there is limited evidence whether a preoperative fluid bolus in patients with a collapsible IVC can prevent this drop in blood pressure.

METHODS

We conducted a single-centre randomized controlled trial with adult patients scheduled to undergo elective noncardiac surgery under general anesthesia (GA). Patients underwent a preoperative point-of-care ultrasound scan (POCUS) to identify those with a collapsible IVC (IVC collapsibility index ≥ 43%). Individuals with a collapsible IVC were randomized to receive a preoperative 500 mL fluid bolus or routine care (control group). Surgical and anesthesia teams were blinded to the results of the scan and group allocation. Hypotension after induction of GA was defined as the use of vasopressors/inotropes or a decrease in mean arterial pressure < 65 mm Hg or > 25% from baseline within 20 min of induction of GA.

RESULTS

Forty patients (20 in each group) were included. The rate of hypotension after induction of GA was significantly reduced in those receiving preoperative fluids (9/20, 45% vs 17/20, 85%; relative risk, 0.53; 95% confidence interval, 0.32 to 0.89; P = 0.02). The mean (standard deviation) time to complete POCUS was 4 (2) min, and the duration of fluid bolus administration was 14 (5) min. Neither surgical delays nor adverse events occurred as a result of the study intervention.

CONCLUSION

A preoperative fluid bolus in patients with a collapsible IVC reduced the incidence of GAIH without associated adverse effects.

STUDY REGISTRATION

ClinicalTrials.gov (NCT05424510); first submitted 15 June 2022.

International consensus on fasting terminology

Although fasting is increasingly applied for disease prevention and treatment, consensus on terminology is lacking. Using Delphi methodology, an international, multidisciplinary panel of researchers and clinicians standardized definitions of various fasting approaches in humans. Five online surveys and a live online conference were conducted with 38 experts, 25 of whom completed all 5 surveys. Consensus was achieved for the following terms: "fasting" (voluntary abstinence from some or all foods or foods and beverages), "modified fasting" (restriction of energy intake to max. 25% of energy needs), "fluid-only fasting," "alternate-day fasting," "short-term fasting" (lasting 2-3 days), "prolonged fasting" (≥4 consecutive days), and "religious fasting." "Intermittent fasting" (repetitive fasting periods lasting ≤48 h), "time-restricted eating," and "fasting-mimicking diet" were discussed most. This study provides expert recommendations on fasting terminology for future research and clinical applications, facilitating communication and cross-referencing in the field.

Development and validation of a predictive model for PACU hypotension in elderly patients undergoing sedated gastrointestinal endoscopy

BACKGROUND

Hypotension, characterized by abnormally low blood pressure, is a frequently observed adverse event in sedated gastrointestinal endoscopy procedures. Although the examination time is typically short, hypotension during and after gastroscopy procedures is frequently overlooked or remains undetected. This study aimed to construct a risk nomogram for post-anesthesia care unit (PACU) hypotension in elderly patients undergoing sedated gastrointestinal endoscopy.

METHODS

This study involved 2919 elderly patients who underwent sedated gastrointestinal endoscopy. A preoperative questionnaire was used to collect data on patient characteristics; intraoperative medication use and adverse events were also recorded. The primary objective of the study was to evaluate the risk of PACU hypotension in these patients. To achieve this, the least absolute shrinkage and selection operator (LASSO) regression analysis method was used to optimize variable selection, involving cyclic coordinate descent with tenfold cross-validation. Subsequently, multivariable logistic regression analysis was applied to build a predictive model using the selected predictors from the LASSO regression. A nomogram was visually developed based on these variables. To validate the model, a calibration plot, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) were used. Additionally, external validation was conducted to further assess the model's performance.

RESULTS

The LASSO regression analysis identified predictors associated with an increased risk of adverse events during surgery: age, duration of preoperative water abstinence, intraoperative mean arterial pressure (MAP) <65 mmHg, decreased systolic blood pressure (SBP), and use of norepinephrine (NE). The constructed model based on these predictors demonstrated moderate predictive ability, with an area under the ROC curve of 0.710 in the training set and 0.778 in the validation set. The DCA indicated that the nomogram had clinical applicability when the risk threshold ranged between 20 and 82%, which was subsequently confirmed in the external validation with a range of 18-92%.

CONCLUSION

Incorporating factors such as age, duration of preoperative water abstinence, intraoperative MAP <65 mmHg, decreased SBP, and use of NE in the risk nomogram increased its usefulness for predicting PACU hypotension risk in elderly patient undergoing sedated gastrointestinal endoscopy.

Effect of Preoperative Clear Liquid Consumption on Postoperative Recovery in Pediatric Patients Undergoing Minimally Invasive Repair of Pectus Excavatum: A Prospective Randomized Controlled Study

Background/Objectives: Preoperative fasting guidelines traditionally aim to reduce pulmonary aspiration risk. However, concerns over the adverse effects of prolonged fasting have led to exploring alternatives. This study aimed to investigate the impact of preoperative clear liquid intake on postoperative outcomes in children undergoing minimally invasive repair of pectus excavatum (MIRPE). Methods: A prospective randomized controlled study was conducted on children aged 3-6 years scheduled for elective MIRPE. Patients were randomized into either a routine overnight fasting group (NPO) or a clear liquid group. The incidence and severity of emergence delirium (ED) were assessed using Pediatric Anesthesia Emergence Delirium (PAED) and Watcha scales at recovery room. Postoperative pain scores and opioid requirements were evaluated at intervals of 1-6 h, 6-12 h, and 12-24 h after surgery. Results: Fasting time was 178.6 ± 149.5 min and 608.9 ± 148.4 min in the clear liquid group compared and NPO group, respectively. The incidence of ED, measured by PAED and Watcha scales, was lower in the clear liquid group (PAED score ≥ 12: 55.6% vs. 85.2%, p = 0.037; Watcha score ≥ 3: 51.9% vs. 85.2%, p = 0.019). The highest PAED score recorded in the recovery room was significantly lower in the clear liquid group (11.4 ± 2.8 vs. 14.6 ± 2.8, p < 0.001). Clear liquid group showed significantly lower pain scores at 1-6, 6-12, and 12-24 h postoperatively. Additionally, clear liquid group had lower opioid requirement at 1-6 and 6-12 h postoperatively. Conclusions: Preoperative clear liquid consumption was associated with a lower incidence of ED in pediatric patients undergoing MIRPE.

Preoperative fasting and the risk of pulmonary aspiration-a narrative review of historical concepts, physiological effects, and new perspectives

In the early days of anaesthesia, the fasting period for liquids was kept short. By the mid-20th century 'nil by mouth after midnight' had become routine as the principles of the management of 'full stomach' emergencies were extended to include elective healthy patients. Back then, no distinction was made between the withholding of liquids and solids. Towards the end of the last century, recommendations of professional anaesthesiology bodies began to reduce the fasting time of clear liquids to 2 h. This reduction in fasting time was based on the understanding that gastric emptying of clear liquids is rapid, exponential, and proportional to the current filling state of the stomach. Furthermore, there was no evidence of a link between drinking clear liquids and the risk of aspiration. Indeed, most instances of aspiration are caused by failure to identify aspiration risk factors and adjust the anaesthetic technique accordingly. In contrast, long periods of liquid withdrawal cause discomfort and may also lead to serious postoperative complications. Despite this, more than two decades after the introduction of the 2 h limit, patients still fast for a median of up to 12 h before anaesthesia, mainly because of organisational issues. Therefore, some hospitals have decided to allow patients to drink clear liquids within 2 h of induction of anaesthesia. Well-designed clinical trials should investigate whether these concepts are safe in patients scheduled for anaesthesia or procedural sedation, focusing on both aspiration risk and complications of prolonged fasting.

Short anesthesia without intravenous fluid therapy in children: Results of a prospective non-interventional multicenter observational study

BACKGROUND

The German guidelines recommend that intravenous fluid therapy should not be mandatorily performed in children with short fasting times undergoing short anesthesia, but there is a lack of clinical studies including a large number of pediatric patients. Therefore, we performed a prospective non-interventional multicenter observational study to evaluate the perioperative hemodynamic and metabolic stability of children undergoing short anesthesia without intravenous fluid therapy.

AIMS

The primary aim was to assess the incidence of hypotension and the secondary aim was to assess the real preoperative fasting times, the incidence of hypoglycemia and the impact on ketone bodies and acid-base balance.

METHODS

Children aged 1 month-18 years undergoing short anesthesia (<1 h) without intravenous fluid therapy were enrolled. Patient demographics, the surgical or diagnostic procedure performed, anesthesia, hemodynamic, laboratory data, and adverse events were documented using a standardized case report form.

RESULTS

Four hundred and twenty seven children that were investigated at three pediatric centers from July 2021 to June 2022 (mean age 83.4 ± 58.9 months, body weight 27.9 ± 19.8 kg) were included in the analysis. The real preoperative fasting times were 14.2 ± 3.6 h for solids, 7.2 ± 3.5 h for milk and 5 ± 4.8 h for clear fluids. During the course of anesthesia, hypotension (<2.5th percentile) was detected in 3 of 427 cases (0.7%), hypoglycemia (glucose <3.0 mmol L-1) in 1 of 355 cases (0.3%), and ketosis (ketone bodies ≥0.6 mmol L-1) in 51 of 233 cases (21.9%). The occurrence of ketosis was associated with lower body weight (p <.001) and longer fasting times for solids or milk (p =.021), but not for clear fluids (p =.69).

CONCLUSIONS

Our study supported the German guidelines recommendation that perioperative intravenous fluid therapy is not mandatory in children beyond the neonatal period with short pre- and postoperative fasting times undergoing short anesthesia (<1 h).

Preoperative clear fluids fasting times in children: retrospective analysis of actual times and complications after the implementation of 1-h clear fasting

BACKGROUND

Preoperative fasting before elective pediatric surgery is a matter of ongoing debate. The objectives of this study were to evaluate the compliance to a recently implemented preoperative fasting protocol (clear fluids until 1 hour from the induction of anesthesia), to identify predictors of prolonged preoperative fasting time, and to determine whether duration of preoperative fasting was associated with adverse outcomes.

METHODS

Retrospective single-center study in an operating theater of a tertiary pediatric hospital.

RESULTS

In a 6-month period, 1820 consecutive patients were analyzed. The data collected in the questionnaire reporting the time of last food, milk and/or liquid intake, and eventual reasons for nonadherence was analyzed. Median (interquartile range) preoperative fasting time was 186 (110-345) min. In 502 patients (27.6%), duration of preoperative fasting to clear fluid ranged from 60 to 119 min, whereas in 616 (34%) it was 120-240 min. The reasons for not respecting fasting time rules are mostly related to communication issues or unwillingness by the patients. A significant difference in fasting times was evident between infants and children older than 10 years (188, 105-290 vs. 198, 115-362; p = 0.02). Fasting times were significantly shorter in the inpatient group and in the first scheduled patients of the morning. Clear fluids fasting times were significantly longer in patients with hypovolemia complications than in those without, 373 (185-685) vs. 180 (110-330) min (p < 0.0001). Longer fasting times to clear fluids, younger age, and scheduled surgery time were independently associated with the odds of experiencing complications.

CONCLUSIONS

In this single pediatric center study, median clear fluids fasting time was three times higher (180 min) than those recommended by the preoperative fasting protocol. Compliance to the protocol was observed in approximately 1 out of 4 patients (27.6%). Longer fasting times were associated with an increased risk of complications, which might be due to dehydration and/or hypovolemia.

Incidence of adverse respiratory events after adjustment of clear fluid fasting recommendations to 1 h: a prospective, observational, multi-institutional cohort study

BACKGROUND

Preoperative fasting reduces the risk of pulmonary aspiration during anaesthesia, and 2-h fasting for clear fluids has commonly been recommended. Based on recent evidence of shorter fasting times being safe, the Swiss Society of Paediatric Anaesthesia began recommending 1-h fasting for clear fluids in 2018. This prospective, observational, multi-institutional cohort study aimed to investigate the incidence of adverse respiratory events after implementing the new national recommendation.

METHODS

Eleven Swiss anaesthesia institutions joined this cohort study and included patients aged 0-15 yr undergoing anaesthesia for elective procedures after implementation of the 1-h fasting instruction. The primary outcome was the perioperative (defined as the time from anaesthesia induction to emergence) incidence of pulmonary aspiration, gastric regurgitation, and vomiting. Data are presented as median (inter-quartile range; minimum-maximum) or count (percentage).

RESULTS

From June 2019 to July 2021, 22 766 anaesthetics were recorded with pulmonary aspiration occurring in 25 (0.11%), gastric regurgitation in 34 (0.15%), and vomiting in 85 (0.37%) cases. No major morbidity or mortality was associated with pulmonary aspiration. Subgroup analysis by effective fasting times (<2 h [n=7306] vs ≥2 h [n=14 660]) showed no significant difference for pulmonary aspiration between these two groups (9 [0.12%] vs 16 [0.11%], P=0.678). Median effective fasting time for clear fluids was 157 [104-314; 2-2385] min.

CONCLUSIONS

Implementing a national recommendation of 1-h clear fluid fasting was not associated with a higher incidence of pulmonary aspiration compared with previously reported data.

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.

Association of infraclavicular axillary vein diameter and collapsibility index with general anesthesia-induced hypotension in elderly patients undergoing gastrointestinal surgery: an observational study

BACKGROUND

The collapse index of inferior Vena Cava (IVC) and its diameter are important predictive tools for fluid responsiveness in patients, especially critically ones. The collapsibility of infraclavicular axillary vein (AXV) can be used as an alternative to the collapsibility of IVC (IVC-CI) to assess the patient's blood volume.

METHODS

A total of 188 elderly patients aged between 65 and 85 years were recruited for gastrointestinal surgery under general anesthesia. Ultrasound measurements AXV and IVC were performed before induction of general anesthesia. Patients were grouped in accordance to the hypotension after induction. ROC curves were used to analyze the predictive value of ultrasound measurements of AXV and IVC for hypotension after induction of anesthesia. Pearson linear correlation was used to assess the correlation of ultrasound measurements and decrease in mean arterial blood pressure (MAP).

RESULTS

The maximum diameter of AXV(dAXVmax) and the maximum diameter of IVC (dIVCmax) were not related to the percentage decrease in MAP; the collapsibility of AXV (AXV-CI) and IVC-CI were positively correlated with MAP changes (correlation coefficients:0.475, 0.577, respectively, p < 0.001). The areas under the curve (AUC) was 0.824 (0.759-0.889) for AXV-CI, and 0.874 (0.820-0.928) for IVC-CI. The optimal threshold for AXV-CI was 31.25% (sensitivity 71.7%, specificity 90.1%), while for IVC-CI was 36.60% (sensitivity 85.9%, specificity 79.0%). Hypotension and down-regulation of MAP during induction can be accurately predicted by AXV-Cl after correction for confounding variables.

CONCLUSION

Infraclavicular axillary vein diameter has no significant correlation with postanesthesia hypotension, whereas AXV-CI may predict postanesthesia hypotension during gastrointestinal surgery of the elderly.

TRIAL REGISTRATION

This study was registered in the Clinical Trial Registry of China on 05/06/2022 (ChiCTR2200060596).

Ultrasonographic Evaluation of Gastric Content and Volume in Pediatric Patients Undergoing Elective Surgery: A Prospective Observational Study

Anesthesia-related complications, such as pulmonary aspiration of gastric contents, occur in approximately 0.02-0.1% of elective pediatric surgeries. Aspiration risk can be reliably assessed by ultrasound examination of the gastric antrum, making it an essential non-invasive bedside tool. In this prospective observational study, since most of our patients are immigrants and have communication problems, we wanted to investigate gastric contents and the occurrence of "high risk stomach" in children undergoing elective surgery for the possibility of pulmonary aspiration, even if the children and/or parents reported their last oral intake time. This risk is defined by ultrasound findings of solid content in the antrum and/or a calculated gastric volume exceeding 1.25 mL/kg. Children aged 2-18 were included in the study. Both supine and right lateral decubitus (RLD) ultrasound examinations were performed on the antrum before surgery. Using a qualitative grading scale from 0 to 2, we evaluated the gastric fluid content. The cross-sectional area (CSA) of the antrum was measured in the RLD position, aiding the calculation of the gastric fluid volume according to an established formula by Perlas. Ultrasound measurements of 97 children were evaluated. The median fasting duration was 4 h for liquids and 9 h for thick liquids and solids. Solid content was absent in all the children. Five children (5.2%) exhibited a grade 2 antrum, implying that fluid content was visible in both the supine and RLD positions. The median antral CSA in the RLD was 2.36 cm2, with a median gastric volume of 0.46 mL/kg. For patients with a grade 0 antrum, a moderate and positive correlation was observed between the antral CSA and BMI, and a strong and positive correlation was evident between the antral CSA and age, similar to a grade 1 antrum. Only a single child (1%) had a potentially elevated risk of aspiration of gastric contents. Hence, the occurrence of a "high risk stomach" was 1% (95% confidence interval: 0.1-4.7%) and is consistent with the literature. As a necessary precaution, we propose the regular use of ultrasound evaluations of gastric contents, given their non-invasive, bedside-friendly, and straightforward implementation, for identifying risks when fasting times are uncertain and for ruling out unknown risk factors in each potential patient.

Randomized controlled trial of liberal vs. standard fasting instructions in percutaneous cardiac procedures

BACKGROUND

Pre-procedural fasting to reduce aspiration risk is usual care prior to surgery requiring anesthesia. Prolonged fasting, however, can result in dehydration and may adversely affect patient experience and outcomes. Previous studies suggest that providing a supplemental beverage to patients undergoing cardiac and a variety of other surgical procedures improves patients' subjective assessment of thirst and hunger and potentially decreases the need for inotrope and vasopressor therapy. Less is known, however, about the effects of ad libitum clear liquids up to 2 h prior to surgery.

METHODS

Adult patients undergoing transcatheter aortic valve replacement (TAVR) or arrhythmia ablation were randomized (1:1) to ad libitum clear liquids up to 2 h prior to their procedure vs. nil per os (NPO) after midnight (control group, usual care). The primary endpoint was a composite satisfaction score that included patient-reported thirst, hunger, headache, nausea, lightheadedness, and anxiousness prior to surgery. The incidence of case-delay was recorded. Intraoperative vasopressor administration, changes in creatinine, anti-emetic use, and hospital length of stay (LOS) were recorded. Safety endpoints including aspiration were assessed.

RESULTS

A total of 200 patients were randomized and 181 patients were included in the final analysis. Overall, 92% of patients were ASA class III or IV and 23% of patients had NYHA class III or IV symptoms. Groups were well balanced with no significant differences in age, sex or baseline cardiac or renal disease. The composite satisfaction score (primary endpoint) was not significantly different between groups (Ad libitum median = 12, IQR = [6, 17], vs Standard NPO median = 10, IQR = [5, 15], [95% CI = [-1, 4]). No significant differences between the two groups were observed in any of the individual survey questions (thirst, hunger, headache, nausea, lightheadedness, anxiousness). No significant differences between groups were observed for intra-operative vasopressor use, changes in creatinine, rescue anti-emetic use or hospital LOS. There were no case delays attributed to the intervention. There were no cases of suspected aspiration.

CONCLUSION

No adverse events or case delays were observed in the ad libitum clears group. No significant benefit, however, was observed in patient satisfaction or any of the pre-specified secondary endpoints in patients randomized to ad libitum clear liquids up to 2 h prior to their procedure.

TRIAL REGISTRATION

NCT04079543.

Efficacy and safety of preoperative chewing gum for undergoing elective surgery: A meta-analysis of randomised controlled trials

AIMS AND OBJECTIVES

This meta-analysis aimed to investigate the safety and feasibility of preoperative chewing gum in adult patients undergoing elective surgery.

BACKGROUND

Postoperative chewing gum has been shown to be safe and effective for most surgeries, while the safety and efficacy of preoperative chewing gum are still controversial.

DESIGN

A meta-analysis of randomised controlled trials was performed.

NO PATIENT OR PUBLIC CONTRIBUTION

This was a meta-analysis involving no people or animals.

METHODS

The literature search was performed in 9 databases from inception to July 2022. Randomised controlled trials that compared the safety and efficacy of preoperative chewing gum and preoperative chewing no gum in adult patients undergoing elective surgery were included. The study was reported in compliance with PRISMA statement.

TRIAL REGISTRATION

PROSPERO CRD42022330223.

RESULTS

Fourteen trials involving 1433 adult patients who undergo elective surgery were pooled in this meta-analysis. The results showed that preoperative chewing gum group resulted in no significant difference in gastric pH (p = .13) and gastric fluid volume (p = .25) compared with non-gum-chewing group. In comparison with the non-gum-chewing group, the gum-chewing group was associated with shorter preoperative thirst score (p = .02), lower incidence of postoperative nausea (p = .0004), lower incidence of postoperative sore throat, lower incidence of postoperative hoarseness, lower postoperative pain score, shorter first postoperative anal exhaust time (p < .00001), shorter first postoperative defecation time (p < .00001) and shorter hospital days (p = .02).

CONCLUSIONS

Preoperative chewing gum was associated with lower discomforts and complication rates, without increasing gastric pH and gastric fluid volume. This strategy may be an innovative, feasible and safe choice for elective surgery in adults.

RELEVANCE TO CLINICAL PRACTICE

This study's results could be used as an evidence for the implementation of preoperative chewing gum in perioperative care for adult patients undergoing elective surgery.

Ultrasound Assessment of Gastric Fluid Volume in Children Scheduled for Elective Surgery After Clear Fluid Fasting for 1 Versus 2 Hours: A Randomized Controlled Trial

BACKGROUND

This study aimed to compare the gastric fluid volume (GFV) in children who fasted 1 versus 2 hours using ultrasound, after ingestion of a defined volume of clear fluid.

METHODS

Children scheduled for elective surgery were enrolled in this randomized, double-blinded, controlled trial. After receiving 3 mL kg -1 clear fluid, participants were randomized to have a gastric ultrasound after fasting for either 1 hour (1-hour group, n = 116) or 2 hours (2-hour group, n = 111). Our primary outcome was the GFV. Other outcomes included the antral cross-sectional area, frequency of high risk and low risk of aspiration, and qualitative grading for the gastric antrum.

RESULTS

Two hundred and twenty-seven children were available for final analysis. The median (Q1-Q3) GFV was higher in the 1-hour group versus the 2-hour group (0.61 [0.41-0.9] mL kg -1 vs 0.32 [0.23-0.47] mL kg -1 ; P value = .001). None of the study groups had GFV ≥1.5 mL kg -1 . The frequency (%) of GFV ≥1.25 mL kg -1 was comparable between both groups (2 [1.7%] vs 0 [0%], P value = .165). However, the frequency of GFV ≥0.8 mL kg -1 was higher in 1-hour group than in 2-hour group (34.5% vs 4.5%), and grade 2 antral grading score was 56.9% in 1-hour group vs 0.9% in 2-hour group ( P value <.001).

CONCLUSIONS

In healthy children scheduled for elective surgery receiving 3 mL kg -1 clear fluid, the median GFV after 1-hour fasting was double the volume after conventional 2-hour fasting. These findings should be considered whether weighting the risk/benefit of a liberal approach to preoperative fasting versus the risk of pulmonary aspiration.

A pragmatic approach to quality improvement in pediatric anesthesia

PURPOSE OF REVIEW

The concept of quality improvement (QI) is well implemented in pediatric anesthesia. Conductance, reporting and publishing of QI projects and -results is well described and promoted. However, the perception of quality might differ between stakeholders and beneficiaries. Based on measures of quality as perceived by healthcare professionals and pediatric patients, a pragmatic approach to choosing the relevant quality measure is suggested.

RECENT FINDINGS

Design of QI projects is often motivated by an incentive to avoid errors and adverse events, and with an overall aim to reduce morbidity and mortality. From a patient- and parent point of view, avoidance of perioperative stress and anxiety might be a priority measure of quality.

SUMMARY

In an attempt to embrace both perspectives of quality in pediatric anesthesia care, it is suggested to choose quality items for improvement based on patient safety, professional excellency and benignancy. By following this approach, QI is expected to remain relevant to both healthcare professionals and patients.

Anxiolytic effects of chewing gum during preoperative fasting and patient-centered outcome in female patients undergoing elective gynecologic surgery: randomized controlled study

Although previous studies reported that chewing gum during the preoperative fasting has the benefits of alleviating anxiety and dry mouth, preoperative chewing gum has yet to be accepted as a standard practice due to conventional anesthetic custom. Our study aimed to prospectively evaluate the effects of gum chewing on preoperative anxiety and patient's discomfort in female patients undergoing gynecologic surgery. Ninety-four patients were enrolled and randomized either into conventional fasting group (control group) or chewing gum with fasting group (gum group). The control group was instructed to fast from 3 p.m. on the day before surgery. The gum group performed preoperative fasting in the same manner, but was encouraged to chew gum freely during the fasting period. The primary endpoint was the degree of preoperative anxiety. For the evaluation of preoperative anxiety, Amsterdam preoperative anxiety and information scale (APAIS) was used. Preoperative gastric fluid volume and acidity were also measured as the secondary outcomes. Preoperative anxiety using APAIS was significantly lower in the gum group compared to the control group (control group vs. gum group: 20.9 vs. 17.8, p = 0.009). However, there was no significant difference in the gastric fluid analysis between the groups. In the female patients for elective gynecologic surgery, chewing gum during the preoperative fasting period helped to alleviate preoperative anxiety without additional increase of pulmonary aspiration risks.Trial registration: KCT0004422 (05/11/2019, https://cris.nih.go.kr ; registration number).

Pre-operative fasting in children: A guideline from the European Society of Anaesthesiology and Intensive Care

Current paediatric anaesthetic fasting guidelines have recommended conservative fasting regimes for many years and have not altered much in the last decades. Recent publications have employed more liberal fasting regimes with no evidence of increased aspiration or regurgitation rates. In this first solely paediatric European Society of Anaesthesiology and Intensive Care (ESAIC) pre-operative fasting guideline, we aim to present aggregated and evidence-based summary recommendations to assist clinicians, healthcare providers, patients and parents. We identified six main topics for the literature search: studies comparing liberal with conservative regimens; impact of food composition; impact of comorbidity; the use of gastric ultrasound as a clinical tool; validation of gastric ultrasound for gastric content and gastric emptying studies; and early postoperative feeding. The literature search was performed by a professional librarian in collaboration with the ESAIC task force. Recommendations for reducing clear fluid fasting to 1 h, reducing breast milk fasting to 3 h, and allowing early postoperative feeding were the main results, with GRADE 1C or 1B evidence. The available evidence suggests that gastric ultrasound may be useful for clinical decision-making, and that allowing a 'light breakfast' may be well tolerated if the intake is well controlled. More research is needed in these areas as well as evaluation of how specific patient or treatment-related factors influence gastric emptying.

Enhanced recovery after surgery: Current status and future progress

Enhanced Recovery After Surgery (ERAS) pathways were first introduced almost a quarter of a century ago and represent a paradigm shift in perioperative care that reduced postoperative complications and hospital length of stay, improved postoperative quality of life, and reduced overall healthcare costs. Gradual recognition of the generalizability of the interventions and transferable improvements in postoperative outcomes, led them to become standard of care for several surgical procedures. In this article, we critically review the current status of ERAS pathways, address related controversies, and propose measures for future progress.

Pro-Con Debate: 1- vs 2-Hour Fast for Clear Liquids Before Anesthesia in Children

Perioperative fasting guidelines are designed to minimize the risk of pulmonary aspiration of gastrointestinal contents. The current recommendations from the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology and Intensive Care (ESAIC) are for a minimum 2-hour fast after ingestion of clear liquids before general anesthesia, regional anesthesia, or procedural sedation and analgesia. Nonetheless, in children, fasting guidelines also have consequences as regards to child and parent satisfaction, hemodynamic stability, the ability to achieve vascular access, and perioperative energy balance. Despite the fact that current guidelines recommend a relatively short fasting time for clear fluids of 2 hours, the actual duration of fasting time can be significantly longer. This may be the result of deficiencies in communication regarding the duration of the ongoing fasting interval as the schedule changes in a busy operating room as well as to poor parent and patient adherence to the 2-hour guidelines. Prolonged fasting can result in children arriving in the operating room for an elective procedure being thirsty, hungry, and generally in an uncomfortable state. Furthermore, prolonged fasting may adversely affect hemodynamic stability and can result in parental dissatisfaction with the perioperative experience. In this PRO and CON presentation, the authors debate the premise that reducing the nominal minimum fasting time from 2 hours to 1 hour can reduce the incidence of prolonged fasting and provide significant benefits to children, with no increased risks.

The effects of diabetes mellitus on gastric emptying: A prospective observational cohort study

STUDY OBJECTIVE

Our goal was to evaluate the effect of diabetic severity and duration on preoperative residual gastric volume. Secondarily we compared ultrasonic estimates of residual gastric volume with actual volume determined by aspiration during endoscopy.

DESIGN

This was a prospective, observational cohort study that included adults with a history of diabetes mellitus and/or opioid use scheduled for gastrointestinal endoscopic procedures.

SETTING

Endoscopy unit at Cleveland Clinic Main Campus from 2017 to 2019.

PARTICIPANT

Adults scheduled for upper endoscopy with or without colonoscopy.

INTERVENTION AND MEASUREMENTS

Residual gastric volumes were primarily determined by aspiration during endoscopy, and secondarily estimated with ultrasound. We evaluated the relationship between gastric residual volume and preoperative HBA1C concentration and duration of diabetes. Secondarily, we conducted an agreement analysis between the two gastric volume measurement techniques.

MAIN RESULTS

Among 145 enrolled patients, 131 were diabetic and 17 were chronic opioid users. Among 131 diabetic patients, the mean ± SD HbA1c was 7.2 ± 1.5% and the median (Q1, Q3) duration of diabetes was 8.5 (3, 15) years. Neither HbA1c nor duration of diabetes was associated with residual gastric volume. The adjusted mean ratio of residual gastric volume was 1.07 (98.3% CI: 0.89, 1.28; P = 0.38) for 1% increase in HbA1c concentration, and 0.84 (98.3% CI: 0.63, 1.14; P = 0.17) for each 10-year increase induration of diabetes. The median [Q1-Q3] absolute difference between gastric ultrasound measurement and endoscopic measurement was 25 [15, 65] ml.

CONCLUSIONS

In this prospective observational cohort study, neither the duration nor severity of diabetes influenced preoperative residual gastric volume. Gastric ultrasound can help identify patients who have excessive residual volumes despite overnight fasting.

Cardiac Output Assessments in Anesthetized Children: Dynamic Capnography Versus Esophageal Doppler

BACKGROUND

The objective of this study was to compare esophageal Doppler cardiac output (COEDM) against the reference method effective pulmonary blood flow cardiac output (COEPBF), for agreement of absolute values and ability to detect change in cardiac output (CO) in pediatric surgical patients. Furthermore, the relationship between these 2 methods and noninvasive blood pressure (NIBP) parameters was evaluated.

METHODS

Fifteen children American Society of Anesthesiology (ASA) I and II (median age, 8 months; median weight, 9 kg) scheduled for surgery were investigated in this prospective observational cohort study. Baseline COEPBF/COEDM/NIBP measurements were made at positive end-expiratory pressure (PEEP) 3 cm H2O. PEEP was increased to 10 cm H2O and COEPBF/COEDM/NIBP was recorded after 1 and 3 minutes. PEEP was then lowered to 3 cm H2O, and all measurements were repeated after 3 minutes. Finally, 20-µg kg-1 intravenous atropine was given with the intent to increase CO, and all measurements were recorded again after 5 minutes. Paired recordings of COEDM and COEPBF were examined for agreement and trending ability, and all parameters were analyzed for their responses to the hemodynamic challenges.

RESULTS

Bias between COEDM and COEPBF (COEDM - COEPBF) was -17 mL kg-1 min-1 (limits of agreement, -67 to +33 mL kg-1 min-1) with a mean percentage error of 32% (95% confidence interval [CI], 25-37) and a concordance rate of 71% (95% CI, 63-80). The hemodynamic interventions caused by PEEP manipulations resulted in significant decrease in COEPBF absolute numbers (155 mL kg-1 min-1 [95% CI, 151-159] to 127 mL kg-1 min-1 [95% CI, 113-141]) and a corresponding relative decrease of 18% (95% CI, 14-22) 3 minutes after application of PEEP 10. No corresponding decreases were detected by COEDM. Mean arterial pressure showed a relative decrease with 5 (95% CI, 2-8) and 6% (95% CI, 2-10) 1 and 3 minutes after the application of PEEP 10, respectively. Systolic arterial pressure showed a relative decrease of 5% (95% CI, 2-10) 3 minutes after application of PEEP 10. None of the recorded parameters responded to atropine administration except for heart rate that showed a 4% relative increase (95% CI, 1-7, P = .02) 5 minutes after atropine.

CONCLUSIONS

COEDM was unable to detect the reduction of CO cause by increased PEEP, whereas COEPBF and to a minimal extent NIBP detected these changes in CO. The ability of COEPBF to react to minor reductions in CO, before noticeable changes in NIBP are seen, suggests that COEPBF may be a potentially useful tool for hemodynamic monitoring in mechanically ventilated children.

Ultrasound Evaluation of Gastric Emptying Time in Healthy Term Neonates after Formula Feeding

BACKGROUND

The current American Society of Anesthesiologists fasting guideline for formula-fed infants in the periprocedural setting is 6 h. Prolonged fasting in very young infants is associated with an increased risk for hypoglycemia and dehydration as well as patient discomfort and patient/parental dissatisfaction. This study aimed to determine the time to gastric emptying in healthy neonates after formula feeding by serially evaluating the gastric antrum with ultrasound. The authors hypothesized that gastric emptying times in formula-fed neonates are significantly shorter than the current 6 h fasting recommendation.

METHODS

After institutional review board approval and written informed parental consent, ultrasound examination was performed in healthy full-term neonates before and after formula feeding at 15-min intervals until return to baseline. Ultrasound images of the gastric antrum were measured to obtain cross-sectional areas, which were then used to estimate gastric antral volumes.

RESULTS

Forty-six of 48 recruited neonates were included in the final analysis. Gastric emptying times ranged from 45 to 150 min and averaged 92.9 min (95% CI, 80.2 to 105.7 min; 99% CI, 76.0 to 109.8 min) in the overall study group. No significant differences were found in times to gastric emptying between male and female neonates (male: mean, 93.3 [95% CI, 82.4 to 104.2 min]; female: mean, 92.6 [95% CI, 82.0 to 103.2 min]; P = 0.930) or those delivered by vaginal versus cesarean routes (vaginal: mean, 93.9 [95% CI, 81.7 to 106.1 min]; cesarean: mean, 92.2 [95% CI, 82.5 to 101.9 min]; P = 0.819).

CONCLUSIONS

These results demonstrate that gastric emptying times are substantially less than the current fasting guideline of 6 h for formula-fed, healthy term neonates.

EDITOR’S PERSPECTIVE

Prediction of gastric fluid volume by ultrasonography in infants undergoing general anaesthesia

BACKGROUND

Point-of-care ultrasonography can estimate gastric contents and volume to assess the risk of pulmonary aspiration; however, its use in infants has not been well validated. We aimed to develop a predictive model for estimating gastric fluid volume using ultrasonography in infants.

METHODS

This prospective observational study enrolled 200 infants (≤12 months) undergoing general anaesthesia. After anaesthetic induction, while preserving spontaneous respiration, we measured gastric antral cross-sectional area using ultrasonography in both the supine and right lateral decubitus positions. We then suctioned the gastric content and measured its volume. The primary outcome was development of a gastric fluid volume prediction model with multiple regression analysis. Agreement between the predicted volume and the suctioned volume was evaluated using a Bland-Altman plot.

RESULTS

Overall, 192 infants were included in the final analysis. Pearson correlation analysis showed that the gastric antral cross-sectional area in the supine (P<0.001; correlation coefficient: 0.667) and right lateral decubitus (P<0.001; correlation coefficient: 0.845) positions and qualitative antral grade (P<0.001; correlation coefficient: 0.581) correlated with suctioned volume. We developed a predictive model: predicted volume (ml)=-3.7+6.5 × (right lateral decubitus cross-sectional area [cm²])-3.9 (supine cross-sectional area [cm²])+1.7 × grade (P<0.01). When comparing the predicted volume and suctioned volume, the mean bias was 0.01 ml kg^-1 and the limit of agreement was -0.58 to 0.62 ml kg^-1.

CONCLUSIONS

Gastric fluid volume can be estimated using a predictive model based on ultrasonography data in infants.

CLINICAL TRIAL REGISTRATION

NCT03155776.

A decade later, there are still major issues to be addressed in paediatric anaesthesia

PURPOSE OF REVIEW

Despite real advances in paediatric anaesthesia management, such as a growing awareness of the relevance of anaesthesia conduct as well as of the lack of evidence for neurotoxicity of anaesthetic agents, it must be said that there are still important questions in our specialty that remain unanswered. Standardization and harmonization of airway management, analgesia techniques and outcome measures are the important issues we are facing at the beginning of this decade.

RECENT FINDINGS

Major improvements in airway management of neonates and infants resulted from the introduction of videolaryngoscopes and the systematic use of nasal oxygenation during endotracheal intubation. Similarly, the increasing popularity of dexmedetomidine has led to the generalization of its use, which, considering that it may produce undesirable effects, poses a challenge for the future. Moreover, recent systematic reviews have confirmed a lack of evidence for the efficacy of many techniques used in clinical practice.

SUMMARY

The shift in research from the neurotoxicity of anaesthetic agents to factors related to anaesthetic conduct are discussed. Examples for an improvement in anaesthesia management are highlighted with advocacy for including these evidence-based findings in routine clinical practice. Finally, the impact of using clinically relevant age-related and patient-centred perioperative outcomes is essential for comparing and/or interpreting the safety and efficacy of anaesthesia and analgesia management in children.

Impact of Modified Anesthesia Management for Pediatric Patients With Williams Syndrome

OBJECTIVE

This study compared the percent change in systolic blood pressure and the incidence of adverse cardiac events (ACEs; defined as cardiac arrest, cardiopulmonary resuscitation, arrhythmias, or ST-segment changes) during anesthesia induction in patients with Williams syndrome (WS) before and after implementation of a perioperative management strategy.

DESIGN

Retrospective observational cohort study.

SETTING

Single quaternary academic referral center.

PARTICIPANTS

The authors reviewed the records of all children with WS at the authors' institution who underwent general anesthesia for cardiac catheterization, diagnostic imaging, or any type of surgery between November 2008 and August 2019. The authors identified 142 patients with WS, 48 of whom underwent 118 general anesthesia administrations. A historic group (HG) was compared with the intervention group (IG).

INTERVENTIONS

Change in perioperative management (three-stage risk stratification: preoperative intravenous hydration, intravenous anesthesia induction, and early use of vasoactives).

MEASUREMENTS AND MAIN RESULTS

The authors determined event rates within 60 minutes of anesthesia induction. Standardized mean difference (SMD) was calculated (SMD >0.2 suggests clinically meaningful difference). Sixty-seven general anesthesia encounters were recorded in the HG (mean age, 4.8 years; mean weight, 16.3 kg) and 51 in the IG (mean age, 6.0 years; mean weight, 18.2 kg). The change in systolic blood pressure was -17.5% (-30.0, -5.0) in the HG versus -9% (-18.0, 5.0) in the IG (p = 0.015; SMD = 0.419), and the incidence of ACEs was 6% in the HG and 2% in the IG (p = 0.542; SMD = 0.207).

CONCLUSIONS

Preoperative risk stratification, preoperative intravenous hydration, intravenous induction, and early use of continuous vasoactives resulted in greater hemodynamic stability, with a 2% incidence of ACEs.

Fasting and surgery timing (FaST) audit

BACKGROUND & AIMS

International guidance advocates the avoidance of prolonged preoperative fasting due to its negative impact on perioperative hydration. This study aimed to assess the adherence to these guidelines for fasting in patients undergoing elective and emergency surgery in the East Midlands region of the UK.

METHODS

This prospective audit was performed over a two-month period at five National Health Service (NHS) Trusts across the East Midlands region of the UK. Demographic data, admission and operative details, and length of preoperative fasting were collected on adult patients listed for emergency and elective surgery.

RESULTS

Of the 343 surgical patients included within the study, 50% (n = 172) were male, 78% (n = 266) had elective surgery and 22% (n = 77) underwent emergency surgery. Overall median fasting times (Q1, Q3) were 16.1 (13.0, 19.4) hours for food and 5.8 (3.5, 10.7) hours for clear fluids. Prolonged fasting >12 h was documented in 73% (n = 250) for food, and 21% (n = 71) for clear fluids. Median fasting times from clear fluids and food were longer in the those undergoing emergency surgery when compared with those undergoing elective surgery: 13.0 (6.4, 22.6) vs. 4.9 (3.3, 7.8) hours, and 22.0 (14.0, 37.4) vs. 15.6 (12.9, 17.8) hours respectively, p < 0.0001.

CONCLUSIONS

Despite international consensus on the duration of preoperative fasting, patients continue to fast from clear fluids and food for prolonged lengths of time. Patients admitted for emergency surgery were more likely to fast for longer than those having elective surgery.

Nulla Per Os (NPO) guidelines: time to revisit?

PURPOSE OF REVIEW

Preoperative fasting guidelines are generalized to elective procedures and usually do not distinguish between the ambulatory and inpatient setting. Prevalence of aspiration is low while prolonged preoperative fasting is common clinical reality. Recently, changes in preoperative fasting guidelines have been widely discussed.

RECENT FINDINGS

Rates of prolonged clear fluid fasting (>4 h) prior to surgery are reported in up to 80% of patients with mean fasting duration of up to 16 h and beyond. Prolonged fasting may result in adverse effects such as intraoperative hemodynamic instability, postoperative delirium, patient discomfort, and extended hospital length of stay. Liberal approaches allowing clear fluids up to 1 h prior to anesthesia or until premedication/call to the operating room have shown no increase in adverse events among children. Various anesthesia societies now encourage clear fluid intake up to 1 h prior to pediatric elective anesthesia. Similar reports in the adult cohort are scarce.

SUMMARY

Allowing sips of water until call to the operating room may help reducing prolonged preoperative fasting and improving patient comfort while keeping a flexibility in operating room schedule. The feasibility and safety of a liberal clear fluid fasting regimen among adults undergoing elective anesthesia needs to be evaluated in future studies.