Residual Gastric Fluid Volume Research Articles

Preoperative clear fluid fasting and endoscopy-measured gastric fluid volume in children.

In light of new recommendations to shorten clear fluid fasting time before anesthesia, our study aimed at exploring residual fluid volume in the stomach after different fasting times. We intended to perform direct endoscopic aspiration of stomach contents under vision, as part of routine gastroscopy assessment. Hereby we would be able to quantify true residual gastric fluid volume and acidity in children and measure their correlation with fasting times. The study was performed as a single-center, prospective study in pediatric perioperative day care at a university-affiliated tertiary care center. Aspiration of gastric fluid contents was performed in anesthetized children aged 1-18 years undergoing an elective gastroscopy. Recorded data included patient fast time, last meal content, last clear fluid content, and aspirated gastric volume and pH, as well as patient characteristics. We included 253 gastroscopies, performed in 245 children. Mean fasting time for clear fluids was 6.9h (range 1h 40 min - 18 h 35 min) (SD 4.5). Mean age was 9.8 years (SD 5.1) and mean body weight was 33.2kg (SD 18.7). Mean residual gastric volume was 12 mL (0-90) (SD 13.5) or 0.34 mL/kg (SD 0.37) and mean pH was 1.5 (SD 0.9). No significant correlation was observed between clear fluid fasting time and the child's residual gastric fluid volume per kg body weight (r= -.103, p= .1), nor between clear fluid fasting time and the pH of the residual gastric fluid (r= -.07, p= .3). In more than half of the patients the residual gastric volume was less than 10mL, unrelated to fasting time. In children undergoing gastroscopy, we could not demonstrate any association between clear fluid fasting time and the child's residual gastric fluid volume per kg body weight. Since we did not see a clinically relevant association between clear fluids fasting time and gastric residual volume, this study may support the recommendation to shorten clear fluids fasting time.

Ultrasonographic evaluation of gastric emptying after ingesting carbohydrate-rich drink in young children: A randomized crossover study.

A recent consensus statement in Europe has suggested that the fasting time for clear liquid in children can be shortened to 1hour before a surgery. However, the study to show that 1-hour fasting time for clear fluids is safe in young children is still lacking. This study aimed to investigate the gastric emptying time for carbohydrate-rich drink and regular 5% glucose solution in children aged 3-7years. After overnight fasting, individuals were randomly assigned to ingest 5mLkg-1 of either carbohydrate-rich drink or 5% glucose solution. One week later, the same subjects were asked to ingest the other one. Ultrasonography was performed to examine the gastric contents. Gastric antral cross-sectional area was measured, and the gastric fluid volume was calculated before and after fluid ingestion within 120minutes. The primary outcome was the gastric emptying time for both the clear fluids calculated using the antral cross-sectional area and logarithms of gastric fluid volume. The degrees of thirst and hunger of two drinks were evaluated using a visual analogue scale as the secondary outcomes. Data from 16 individuals were analyzed. In the glucose solution group, the antral cross-sectional area and logarithms of gastric fluid volume returned to baseline at 30minutes after ingestion. However, in the carbohydrate-rich drink group, the median [interquartile range; range] antral cross-sectional area (3.69 [2.64-5.15; 1.83-8.93] cm2 vs 2.41 [2.10-2.96; 1.81-4.37] cm2 , P<.001) and mean (95% confidence interval) logarithms of gastric fluid volume (2.54 [2.30-2.79] mL vs 2.12 [1.94-2.30] mL, P=.048) were still higher than at 60minutes and returned to the baseline values at 90minutes after ingestion, respectively. The degree of thirst was lower in the glucose solution group than that in the carbohydrate-rich drink group. Gastric emptying of carbohydrate-rich drink is slower than that of 5% glucose solution but the residual gastric fluid volume is low one hour after ingestion of 5mLkg-1 of either fluid.

Assessing the effect of sugar-free chewing gum use on the residual gastric volume of patients fasting for gastroscopy: A randomised controlled trial.

There is no clear consensus in the current guidelines published by major international anaesthetic associations on what is the most appropriate time for a patient to stop chewing gum. This open-label balanced-group randomised controlled trial aimed to evaluate whether the chewing of sugar-free gum caused an increased volume or reduced pH of residual gastric fluid in fasting patients. For this study 212 patients undergoing elective gastroscopy were randomised into a control group who followed routine fasting instructions and an intervention group who were asked to chew gum while fasting. Residual gastric fluid was aspirated under direct vision via a gastroscope under anaesthesia. The primary outcome was the incidence of a gastric residual volume &gt;50 ml in participants who chewed gum compared with a control group. Secondary outcomes were variability in the overall gastric volume distribution and gastric pH distribution between the two groups. Nine out of 110 (8.2%) in the chewing gum group and six out of 102 (5.9%) in the control group had a residual gastric fluid volume &gt;50 ml: incidence rate ratio 1.39 (95% confidence intervals (CI) 0.51–3.77; P = 0.60). However, only one patient (in the control group) had a residual gastric volume &gt;73 ml. There was no statistically significant difference in gastric volume distribution between groups, odds ratio 1.60 (95% CI 0.99–2.58; P = 0.054) or in the distribution of gastric pH measurement, odds ratio 0.90 (95% CI 0.57–1.44; P = 0.67). These results indicate that if there is an increase in the incidence of residual gastric volume &gt;50 ml in patients who chew gum preoperatively, it is likely to be small. Moreover, the absence of any patients in our chewing gum group with a residual gastric volume &gt;73 ml is reassuring.

Ultrasonographic evaluation of gastric contents in term pregnant women fasted for six hours

BackgroundCurrent fasting guidelines suggest six hours are adequate to minimise the aspiration risk after a light meal consumed by pregnant women undergoing elective caesarean section. We assessed gastric contents in non-labouring pregnant women, using ultrasonographic analysis. MethodsIn a prospective study, pregnant women ≥36 weeks’ gestation, without conditions likely to influence gastric emptying, underwent ultrasonographic analysis of their gastric antrum, after six hours of fasting following a standardised light meal. The primary outcome was solid food content in the antrum. Other outcomes included fluid in the supine and right lateral positions, antral cross-sectional area and estimated residual gastric fluid volume. Antral grades were classified: grade 0 = absence of fluid in both supine and right lateral positions: grade 1 = fluid present in the right lateral position only: grade 2 = fluid in both positions. ResultsComplete data were available in 46/51 (90%) women. No woman had solid food visible. Antral grades 0, 1 and 2 were seen in 6 (13%), 36 (78%) and 4 (9%) women respectively. Eighteen of 48 women (37.5%) had a residual volume greater than 1.5 mL/kg. Of those with a grade 1 antrum, 13/36 (36%) had residual volumes in excess of 1.5 mL/kg. For grade 2, this was 4/4 (100%). ConclusionsOur cohort of pregnant women fasted for six hours had no solid food visible in the antrum, but many had both qualitative and quantitative ultrasonographic evidence of gastric volumes potentially associated with aspiration risk. This suggests that pregnancy-specific fasting guidelines may be required.

Effect of gum chewing on gastric volume and emptying: a prospective randomized crossover study

BackgroundCurrent fasting guidelines allow oral intake of water up to 2 h before induction of anaesthesia. We assessed whether gum chewing affects gastric emptying of 250 ml water and residual gastric fluid volume measured 2 h after ingestion of water. MethodsThis prospective randomized observer-blind crossover trial was performed on 20 healthy volunteers who attended two separate study sessions: Control and Chewing gum (chlorophyll flavour, with 2.1 g carbohydrate). Each session started with an ultrasound measurement of the antral area, followed by drinking 250 ml water. Then, volunteers either chewed a sugared gum for 45 min (Chewing gum) or did not (Control). Serial measurements of the antral area were performed during 120 min, and the half-time to gastric emptying (t½), total gastric emptying time, and gastric fluid volume before ingestion of water and 120 min later were calculated. ResultsGastric emptying of water was not different between sessions; the mean (sdsd) t½ was 23 (10) min in the Control session and 21 (7) min in the Chewing gum session (P=0.52). There was no significant difference between sessions in gastric fluid volumes measured before ingestion of water and 120 min later. ConclusionsChewing gum does not affect gastric emptying of water and does not change gastric fluid volume measured 2 h after ingestion of water. Clinical trial registrationNCT02673307.

Quality indicators common to all GI endoscopic procedures

Quality of care is the degree to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge (1). The American Society for Gastrointestinal Endoscopy (ASGE), the American College of Gastroenterology (ACG), and the American Gastroenterological Association (AGA) have continually promoted the ideal that all patients have access to high-quality GI endoscopy services. A high-quality endoscopy is an examination in which patients receive an indicated procedure, correct and relevant diagnoses are recognized or excluded, any therapy provided is appropriate, and all steps that minimize risk have been taken.

Oral Contrast for Abdominal Computed Tomography in Children

Oral enteric contrast medium (ECM) is frequently administered to achieve visualization of the gastrointestinal tract during abdominal evaluation with computed tomography (CT). Administering oral ECM less than 2 hours before sedation/anesthesia violates the nothing-by-mouth guidelines and in theory may increase the risk of aspiration pneumonia. In this study we measured the residual gastric fluid when using a protocol in which ECM is administered up to 1 hour before anesthesia/sedation. We hypothesized that patients receiving ECM 1 hour before anesthesia/sedation would have residual gastric fluid volume (GFV) >0.4 mL/kg. Anesthesia and radiology reports, CT images, and department incident reports were reviewed between January 2005 and June 2009 for all patients who required sedation/anesthesia for abdominal CT. For each patient, the volume of contrast or stomach fluid was calculated using a region of interest outlining the stomach portion containing high-attenuation fluid and low-attenuation of other gastric contents. Information obtained from anesthesia/sedation reports included demographic characteristics, presenting pathology, drugs used for anesthesia/sedation induction and maintenance, airway interventions, method for securing endotracheal tube, and complications related to ECM administration, including oxygen desaturation, vomiting, coughing, bronchospasm, laryngospasm, and aspiration. We identified 365 patients (mean age = 32 months; range = 0.66 to 211.10 months) who received oral/IV contrast material before anesthesia/sedation for abdominal CT and 47 patients (mean age = 52 months; range = 0.63 to 215.84 months) who received only IV contrast material and followed the traditional fast. For those who received oral contrast, the mean contrast volume administered was 18.10 mL/kg (range = 1.5 to 82.76 mL/kg). The median GVF 1 hour after completing the oral contrast was significantly higher than that in patients who received only IV contrast (0.38 mL/kg vs. 0.15 mL/kg, P = 0.0049). GFV exceeded 0.4 mL/kg in 189 patients (178 of 365 [49%] in the oral contrast group vs. 11 of 47 [23%] in the IV contrast group) (χ(2) = 10.7874, P = 0.0010). Among those who received oral contrast, 207 patients had general anesthesia and 158 patients had deep sedation. Two cases of vomiting were reported in the general anesthesia group with no evidence of pulmonary aspiration identified. For children receiving an abdominal CT, the residual GFV exceeded 0.4 mL/kg in 49% (178/365) of those who received oral ECM up to 1 hour before anesthesia/sedation in comparison with 23% (11/47) of those who received IV-only contrast.

Split-dose bowel preparation for colonoscopy and residual gastric fluid volume: an observational study

Split-dose bowel preparations for colonoscopy are more effective and better tolerated than preparations given entirely the day or evening before the procedure; however, some resistance to split-dose preparation stems from concerns about an increased risk of aspiration with same-day preparation. We sought to evaluate residual gastric volumes in patients after split-dose bowel preparations. Prospective measurement of residual gastric volumes in patients undergoing same-day EGD and colonoscopy after split-dose bowel preparations, patients undergoing EGD alone, or patients undergoing EGD and colonoscopy after bowel preparation given entirely the evening before the procedure. Tertiary care hospital-based endoscopy unit. This study involved 712 patients, including 254 in the split-dose bowel preparation group, 411 in the EGD-only group, and 47 in the evening-before-procedure bowel preparation group. Measurement of residual gastric volume before endoscopic procedures. Residual gastric volume. The mean residual gastric volume in patients receiving split-dose bowel preparation (19.7 mL) was higher than in patients undergoing EGD alone (14.6 mL) but not different from that in patients receiving bowel preparation the evening before the procedure (20.2 mL). Within the split-dose preparation group, there was no association between the interval from last actual fluid ingestion and procedure start time and the residual gastric volume. The range of residual gastric volumes between study arms was similar. Nonrandomized study. The number of inpatients undergoing split-dose bowel preparation was small. These data support the safety of split-dose bowel preparation for outpatients undergoing colonoscopy.

Residual Gastric Fluid Volume and Chewing Gum Before Surgery

Residual Gastric Fluid Volume and Chewing Gum Before Surgery

Residual Gastric Fluid Volume and Chewing Gum Before Surgery

In this study we sought to determine if chewing gum preoperatively increases gastric fluid volume (GFV) and changes gastric acidity. Children, 5-17 yr old, were randomized to one of three groups: a control group that was not given any gum, a group that was given sugarless bubble gum, and a group that was given sugared bubble gum. Patients in the two gum groups were instructed to chew their gum for a period of 30 min. After induction of anesthesia and tracheal intubation, the stomach was suctioned with a salem sump orogastric tube. We found that children who did not chew gum had significantly smaller GFV as compared with children who chewed sugared and sugarless gum (0.35 [0.2-0.5] mL/kg versus 0.88 [0.6-1.4] mL/kg versus 0.69 [0.4-1.6] mL/kg; P = 0.0001). Children who did not chew gum also had a significantly lower gastric fluid pH as compared with children chewing sugared and sugarless gum (geometric mean, 1.91 versus 2.25 versus 2.19; P = 0.007). We conclude that children who present for surgery while chewing gum have significantly larger GFV and higher pH.

Preoperative fasting and administration of regular medications in adult patients presenting for elective surgery. Has new evidence changed clinical practice?

The duration of preoperative fasting from solid food and liquids, a time-honoured anaesthetic practice, has been the subject of extensive clinical investigations [1,2], editorial comment [3] and speciality guidelines [4,5] in the past decade. Dr Pearse and colleagues' study of current UK clinical practice relating to the duration of preoperative fasting of adult patients and compliance with ongoing cardiac drug administration is therefore timely [6]. Historically, preoperative fasting has not always been a prerequisite of safe, prudent anaesthetic practice. Lister, in the late 19th century, advised oral fluid intake up to two hours before anaesthesia [7]. Despite a body of recent evidence in support of Lister's conclusions, clinicians have continued to err on the side of caution and practice the maxim that 'longer is better'. Mendelson described the risk of gastric acid aspiration during obstetric anaesthesia with the consequent development of pneumonitis in his landmark 1946 study [8]. The conventional wisdom was that techniques to minimize the volume and increase the pH of the gastric contents would reduce the risk of Mendelson's syndrome. The concept of 'nil by mouth' (or in North America NPO), encompassing both fluids and food after midnight, was regarded as a logical practice to ensure an empty stomach at the time of surgery. Prolonged preoperative fasting contributes to patient discomforts, including dry mouth and thirst. In addition, the practice may, in some situations, lead to dehydration, hypovolaemia, and nausea and vomiting [9]. If excess gastric acidity was also a consequence, surely the practice should warrant a major review? The most noteworthy data arising from Pearse and colleagues' study involving 153 adult patients were the range of fasting times. For solids, the range was from 4 h and 30 min to 48 h and for fluids the range was from 4 h 30 min up to 20 h. Concerns about preoperative fasting may be a significant factor in the omission of usual concurrent drug treatment as highlighted in this study. Approximately 25% of patients undergoing elective surgery take regular concurrent medication [10]. Wyld and Nimmo [11] reported that analgesic and pre-medication subscriptions are routinely given. However, 38 of 95 drug treatments for cardiovascular disease, 34 of 103 for respiratory disease and 10 of 61 for endocrine disorders were omitted. When clinical studies in adults undertaken at the Foothills Hospital, Calgary, confirmed that an oral intake of 150 mL water [12] and subsequently coffee or fruit juice [13] 2-3 h before scheduled elective surgery had no clinically important effect on residual gastric fluid volume or pH, fasting guidelines for ambulatory patients were amended to prohibit solid food but permit clear fluid intake. The Canadian Anaesthetists' Society subsequently published guidelines stating that fasting for oral fluids for more than 3 h is unnecessary in healthy patients undergoing elective surgery. The American Society of Anesthesiologists Task Force on preoperative guidelines, published in 1999, were unequivocal in their recommendation that it is appropriate to fast for oral fluids for 2 h or more before procedures requiring general/regional anaesthesia or monitored anaesthesia care in adult patients. Clear liquids include, but are not limited to, water, fruit juices, carbonated beverages, clear tea and black coffee. Clinical investigations and the authority of society practice guidelines has an impact on North American clinical practice because the majority of institutions, both university and private practice, revised their fasting policies in recent times [14]. Why is British practice so slow to change? Perhaps anaesthetists fear that, if the absolute fasting rule is relaxed, patients will eat and drink at will, with subsequent delay or cancellation of surgical procedures. A concerted effort to inform surgeons, nurses and patients of the rationale behind current fasting guidelines enabling both ambulatory and in-patient to take, if they wish, clear fluids before surgery will enhance patient comfort and, considering the vagaries of operating theatre schedules, will be a safe, cost-effective practice. Judith Connolly, MRCPI, FFARCSI Anthony J. Cunningham, MD, FRCPC Departments of Anaesthesia and Critical Care Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9

Shortened preanesthetic fasting interval in pediatric cardiac surgical patients.

The recent liberalization of preoperative feeding orders in healthy pediatric outpatients prompts the question of whether this applies to children about to have cardiac surgery. The authors compared gastric fluid volume and pH in two groups of children undergoing elective cardiac surgery, one of which was not only permitted ad libitum clear liquids but was mandated to drink clear liquids 2-3 h before induction of anesthesia (study group). The other group followed routine inpatient preoperative fasting orders (control group). The study group (n = 44) averaged 3.1 +/- 4.1 yr and weighed 15.3 +/- 16.3 kg; the control group averaged 3.3 +/- 3.9 yr and weighed 14.3 +/- 12.1 kg (P = 0.82, 0.73, respectively). Aspiration of residual gastric fluid volume was attempted in all patients after induction of anesthesia. Gastric fluid volume averaged 0.6 +/- 0.9 mL/kg in the study group and 0.4 +/- 0.6 mL/kg in the control group (P = 0.13). Of the study patients, 41% had a measured gastric volume greater than or equal to 0.4 mL/kg compared with 32% of the control patients (P = 0.50). Of the 42 patients who had residual gastric fluid aspirated, pH determinations were completed on 37 aspirates; of these 19 of 20 (95%) in the study group and 14 of 17 (82%) in the control group had a gastric pH less than or equal to 2.5. Using a linear analogue scale, parents rated children in the study group to be more comfortable, less hungry, and less thirsty compared with the control patients (P = 0.004, 0.002, 0.0001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Gastric fluid volume and pH in elective patients following unrestricted oral fluid until three hours before surgery

This clinical study was designed to assess the results of new preoperative fasting guidelines in which patients are instructed that they must not eat any solid food after midnight, but that they may drink unrestricted amounts of clear fluid until three hours before their scheduled time of surgery. We studied 199 healthy, elective surgical inpatients aged 18-70 yr to determine whether there was any correlation between the ingestion interval or the volume of fluid ingested, with the volume and pH of residual gastric fluid at induction of anaesthesia. Pregnant patients, and those with gastric disorders or who were taking medications that affect gastric motility or secretion, were excluded. Either no premedication was given, or oral diazepam 5-15 mg was given 90 min preoperatively. Of the 199 patients, 105 ingested 50-1200 ml on the morning of surgery. The ingestion-induction interval was less than three hours in 12 patients whose actual surgery time was ahead of schedule. The remaining 94 patients did not drink because they were scheduled for surgery before 11:00 (n = 51), they did not want to drink (n = 24), or they were advised not to drink by their nurse or surgeon (n = 16). Following induction of anaesthesia, gastric fluid was aspirated through a #18 Salem sump orogastric tube, the volume was recorded and pH was measured with a calibrated pH meter. Patients were divided retrospectively into four groups (in three of which patients ingested fluid) according to the ingestion-induction interval (1.3-3.0 hr, 3.1-5.0 hr, 5.1-8.0 hr, and nothing by mouth after midnight).(ABSTRACT TRUNCATED AT 250 WORDS)