Reliability of the [13C]‐acetate breath test in the measurement of gastric emptying of ethanol solutions: a methodological study

Background: The [ ¹³ C]‐acetate breath test is a clinically well‐established test for measuring gastric emptying of liquids and correlates significantly with scintigraphy. However, no studies have been undertaken to examine the relationship between gastric emptying measured by the [ ¹³ C]‐acetate breath test and ultrasonography. Furthermore, it is not known how ethanol may affect gastric emptying as measured by the [ ¹³ C]‐acetate breath test. This is particularly important because of the additional steps of absorption, metabolism and exhalation of the tracer involved in the [ ¹³ C]‐acetate breath test compared to the simple measurement of gastric emptying by ultrasonography. The aim of the present study was to examine the relationship between the gastric half emptying times measured by the [ ¹³ C]‐acetate breath test and by ultrasonography and to determine the effect of ethanol on the comparability between both methods. Methods: On separate days, 10 healthy, fasted randomly selected subjects received the following solutions by gastric tube: 500?mL water, 4% and 10% (v/v) ethanol, 5.5% and 11.4 % (w/v) glucose. Gastric half emptying times of the test solutions were simultaneously determined using the [ ¹³ C]‐acetate breath test and ultrasonography of the fundus and the antrum. Results: The gastric emptying rates determined by ultrasonography of the fundus correlated significantly with the results obtained using the [ ¹³ C]‐acetate breath test for all test solutions (r?=?0.64–0.92, P?r?=?0.94, P?=?0.001) was used. The difference between the mean half‐emptying times obtained using the [ ¹³ C]‐acetate breath test and ultrasonography of the fundus was 55?±?1.8?min. This difference was significantly longer when 4% and 10% (v/v) ethanol solutions were given (61.2?±?3.3 and 71.2?±?2.9?min) compared to water (P?Conclusions: A good correlation was found between gastric emptying as measured by the [ ¹³ C]‐acetate breath test and ultrasonography of the fundus. Measurements that were obtained using the [ ¹³ C]‐acetate breath test demonstrate a longer gastric half emptying time compared with those obtained using ultrasonography. This difference is even more marked when ethanol solutions are used. Presumably, this is because ethanol affects the absorption and/or the hepatic metabolism of the tracer. The [ ¹³ C]‐acetate breath test is therefore not a reliable gastric emptying test for comparison of different solutions, especially when ethanol‐containing liquids are used.     

Effect of ethanol and some alcoholic beverages on gastric emptying in humans

BACKGROUND: There is a paucity of detailed and controlled studies on the action of ethanol and alcoholic beverages on gastric emptying in humans. This study was designed to compare the effect of beer, red wine, whisky and their comparable pure ethanol solutions on gastric emptying in a controlled and randomized investigation. METHODS: On separate days, 10 healthy, fasted subjects received the following solutions, in random order, through a gastric tube: 500 mL beer, red wine, comparable pure ethanol solutions (4% and 10% v/v), glucose (5.5% and 11.4% w/v) and water, 125 mL whisky and 40% (v/v) ethanol (both followed by 125 mL water) and 250 mL water. Gastric emptying of the test solutions was assessed using ultrasonography of the antrum. RESULTS: As measured by ultrasonography of the antrum, half emptying times of the ethanol solutions (4%, 10% and 40% v/v) were significantly (P < 0.05) longer (22.6 +/- 4.8, 22.7 +/- 4.3 and 27.8 +/- 3.3 min, respectively, n=10) than those of water (14.6 +/- 1.9 min (500 mL) and 13.2 +/- 1.7 min (250 mL), respectively). The half emptying times of beer (39.3 +/- 4.3 min) and red wine (72.6 +/- 7.6 min) were significantly longer than those of the corresponding ethanol concentrations, whereas whisky was emptied at nearly the same rate (26.4 +/- 5.9 min) as 40% (v/v) ethanol. Emptying of glucose 5.5% and 11.4% (w/v) was significantly and dose dependently slower (29.7 +/- 4.5 and 64.8 +/- 8.9 min) than water. CONCLUSIONS: 1) Pure ethanol in concentrations of 4%, 10% and 40% (v/v) inhibits gastric emptying. 2) The inhibitory effect of beer and red wine, but not of whisky, is stronger than that of their comparable ethanol concentrations. 3) Caloric content and non-alcoholic ingredients in alcoholic beverages produced by fermentation (beer and wine), but not in those produced by distillation (whisky), are most likely responsible for this effect.     

Effect of ethanol and some alcoholic beverages on gastric emptying in humans

Background: There is a paucity of detailed and controlled studies on the action of ethanol and alcoholic beverages on gastric emptying in humans. This study was designed to compare the effect of beer, red wine, whisky and their comparable pure ethanol solutions on gastric emptying in a controlled and randomized investigation. Methods: On separate days, 10 healthy, fasted subjects received the following solutions, in random order, through a gastric tube: 500?mL beer, red wine, comparable pure ethanol solutions (4% and 10% v/v), glucose (5.5% and 11.4% w/v) and water, 125?mL whisky and 40% (v/v) ethanol (both followed by 125?mL water) and 250?mL water. Gastric emptying of the test solutions was assessed using ultrasonography of the antrum. Results: As measured by ultrasonography of the antrum, half emptying times of the ethanol solutions (4%, 10% and 40% v/v) were significantly (P?n?=?10) than those of water (14.6?±?1.9?min (500?mL) and 13.2?±?1.7?min (250?mL), respectively). The half emptying times of beer (39.3?±?4.3?min) and red wine (72.6?±?7.6?min) were significantly longer than those of the corresponding ethanol concentrations, whereas whisky was emptied at nearly the same rate (26.4?±?5.9?min) as 40% (v/v) ethanol. Emptying of glucose 5.5% and 11.4% (w/v) was significantly and dose dependently slower (29.7?±?4.5 and 64.8?±?8.9?min) than water. Conclusions: 1) Pure ethanol in concentrations of 4%, 10% and 40% (v/v) inhibits gastric emptying. 2) The inhibitory effect of beer and red wine, but not of whisky, is stronger than that of their comparable ethanol concentrations. 3) Caloric content and non‐alcoholic ingredients in alcoholic beverages produced by fermentation (beer and wine), but not in those produced by distillation (whisky), are most likely responsible for this effect.     

Retention,Fixation, and Loss of the [<Superscript>13</Superscript>C] Label: A Review for the Understanding of Gastric Emptying Breath Tests

A [13C]-breath test is a promising method for measuring gastric emptying. The methodological relevance is based on a close correspondence between gastric emptying of [13C]-acetate/octanoate (input) and pulmonary excretion of [13CO2] (output). Despite the close input-output correspondence, the pulmonary output is quite remote from the gastric input: the pulmonary output is delayed compared to the gastric input, and the total recovery of [13CO2] in the breath is incomplete. This review focuses on the kinetics of [13C]-acetate/octanoate in the body and suggests that (1) the delayed pulmonary output results from temporal retention of [13CO2] in the well-perfused tissues (heart, brain, etc.), (2) the incomplete recovery results from incorporation of the label into metabolic products (ketone bodies, amino acids, etc.) or from fixation of [13CO2] in the low-perfused tissues (bone, skeletal muscle, etc.), and (3) knowledge on the retention is the key to appropriate interpretations of breath test results. Recognition of these kinetic aspects is essential for appropriate interpretations of these breath test results.     

Influence of cisapride on gastric emptying of solids and liquids monitored by13C breath tests

[¹³C]Acetate and [¹³C]octanoate breath tests were used to analyze the gastric emptying of liquids and solids in healthy controls and patients with functional dyspepsia both with and without cisapride. A standard test meal was labeled with either 150 mg [¹³C]acetate (liquid phase labeled in the water) or with 100 mg [¹³C]octanoate (solid phase labeled in the egg yolk). Six patients with dyspepsia and six healthy controls underwent a 4-hr breath test four times, ie, both the [¹³C]acetate and [¹³C]octanoate test with and without cisapride. Duplicate [¹³C]acetate or [¹³C]octanoate breath tests were performed in another 12 healthy controls in order to assess day-to-day variability of gastric emptying for liquids and solids. The mass spectrometric data were fitted to a power exponential function allowing mathematical analysis of half-emptying times and lag times. In patients with dyspepsia, gastric half emptying times of solids were significantly delayed as compared to the emptying of solids in the controls (203±41 vs 148±35 min;P<0.05). With cisapride, gastric emptying of solids was significantly accelerated (P<0.05) both in the patients (166±58 min) and in the controls (117±27 min). The gastric emptying of liquids did not differ in patients and controls, and cisapride had no effect on the emptying of liquids within the normal range. In the healthy controls, half emptying times both for liquids and solids were reproducible on the two different days (CV_intra: 5.58% for liquis, 20.01% for solids). We conclude that as an entirely noninvasive and nonradioactive tool¹³C-labeled breath tests are well reproducible and allow assessment of the effect of cisapride on the characteristics of gastric emptying.     

Toward office-based measurement of gastric emptying in symptomatic diabetics using [13C]octanoic acid breath test

OBJECTIVE: Current methods for measuring gastric emptying by breath test require sampling over several hours and are too inaccurate for clinical use. The aim of this study was to develop an office-based method for measuring gastric emptying of solids in patients with diabetes using a [13C]octanoic acid breath test. METHODS: In 22 symptomatic diabetic patients (17 insulin-dependent diabetes, 5 non-insulin-dependent diabetes) and 6 controls, we simultaneously measured gastric emptying of an egg meal (420 kcal) by scintigraphy and [13C]octanoic acid breath test. Conventional (nonlinear) methods for scintigraphic and [13C]octanoic acid breath test emptying and generalized linear regression method to predict scintigraphic half-life (t(1/2)) using four breath samples obtained during the first 3 h. RESULTS: Despite 8 h of breath sampling, the t(1/2) estimate using the conventional method was markedly different from the scintigraphic value (delta t(1/2): median, 113 min; range, 19-282 min). The generalized linear model (using samples at baseline, 30, and 120 or 150 min) yielded predicted scintigraphic tLAG and t(1/2) that were more accurate than the conventional method; mean standard deviations of differences were 16 and 27 min, respectively. Breath test correctly assessed normal or prolonged emptying in 21 of 22 patients. CONCLUSIONS: The [13C]octanoic acid breath test can be simplified to measure gastric tLAG and t(1/2) and can be expected to correctly identify normal t(1/2) in symptomatic diabetics. Further refinement of the model will need to include studies of patients with markedly delayed t(1/2).     

The Wagner-Nelson method can generate an accurate gastric emptying flow curve from CO2 data obtained by a 13C-labeled substrate breath test

BACKGROUND: In pharmacokinetics, the Wagner-Nelson (W-N) method can accurately estimate the rate of drug absorption from its urinary elimination rate. A stable isotope (13C) breath test attempts to estimate the rate of absorption of 13C, as an index of gastric emptying rate, from the rate of pulmonary elimination of 13CO2. The time-gastric emptying curve determined by the breath test is quite different from that determined by scintigraphy or ultrasonography. In this report, we have shown that the W-N method can adjust the difference. METHODS: The W-N equation to estimate gastric emptying from breath data is as follows: the fractional cumulative amount of gastric contents emptied by time t = Abreath (t)/Abreath (infinity) + (1/0.65).d[Abreath (t)/Abreath (infinity) ]/dt, where Abreath (t) = the cumulative recovery of 13CO2 in breath by time t and Abreath ( infinity ) = the ultimate cumulative 13CO2 recovery. The emptying flow curve generated by ultrasonography was compared with that generated by the W-N method-adjusted breath test in 6 volunteers. RESULTS: The emptying curves by the W-N method were almost identical to those by ultrasound. CONCLUSIONS: The W-N method can generate an accurate emptying flow curve from 13CO2 data, and it can adjust the difference between ultrasonography and the breath test.     

Gastric emptying time of fluids and solids in healthy subjects determined by 13C breath tests: influence of age, sex and body mass index

BACKGROUND AND AIM: Disturbance of gastric emptying leads to a variety of symptoms. Furthermore, gastric motility disorders might play a role in the pathophysiology of functional dyspepsia. In previous studies 13C breath tests were validated as non-invasive tools in the measurement of gastric emptying time. So far, reliable reference values of healthy subjects are missing and the impact of constitutional traits (age, sex, body mass index [BMI]) needs to be clarified. METHODS: A study was conducted in 90 healthy individuals (45 men, 45 women) that assessed the correlation of parameters of gastric emptying (half gastric emptying time [T1/2] and time of fastest gastric emptying [T(lag)]) with age, sex and BMI for fluid and solid test meals by 13C breath tests. 100 mg of sodium acetate or sodium octanoate, respectively, were used as tracers. Breath probes were analyzed by non-dispersive infrared spectroscopy. RESULTS: The mean +/- SD of half gastric emptying time (T1/2) of a fluid test meal was determined to be 80.5 +/- 22.1 min and for T(lag) to be 40.3 +/- 10.2 min. However, the T1/2 and T(lag) of solid meals did not fit to normal distribution and thus median and percentiles were determined. The median time of T1/2 for solids was 127 min (25-75% percentiles: 112.0-168.3 min) and 81.5 min for T(lag) (25-75% percentiles: 65.5-102.0 min). No significant correlation was found between gastric emptying and age, sex or BMI. CONCLUSION: This is the first study to examine gastric emptying in an adequate number of healthy subjects by 13C breath tests. No significant correlation was found with age, sex and BMI. Although there is considerable standard deviation in gastric emptying time, these results may nevertheless serve as reference values for further studies.     

Measurement of gastric emptying in non-ulcer dyspepsia]

Using real-time ultrasonography, we monitored gastric emptying indirectly in 26 cases of non-ulcer dyspepsia (NUD) and 13 healthy adults by determining the anteroposterior gastric measurement of a single section of the stomach in the corpus fundus immediately after drinking 500 ml water and then every 10 min. for five times. The average time for 50% gastric emptying in NUD patients (36.46 +/- 13.13, x +/- s) was longer than that in healthy adults (23.54 +/- 5.93), but the half time of gastric emptying in male with NUD was not significantly different as compared with that in male controls and female patients of NUD.     

Effect of DA-9701 on gastric emptying in a mouse model: Assessment by ¹³C-octanoic acid breath test

AIM:To evaluate the effects of DA-9701 on the gastric emptying of a solid meal using the 13C-octanoic acid breath test in a mouse model. METHODS:Male C57BL/6 mice aged > 8 wk and with body weights of 20-25 g were used in this study. The solid test meal consisted of 200 mg of egg yolk labeled with 1.5 L/g 13C-octanoic acid. The mice were placed in a 130 mL chamber flushed with air at a flow speed of 200 mL/min. Breath samples were collected for 6 h. The half-emptying time and lag phase were calculated using a modified power exponential model. To assess the reproducibility of the 13C-octanoic acid breath test, the breath test was performed two times at intervals of one week in ten mice without drug treatment. To assess the gastrokinetic effects of DA-9701, the breath test was performed three times in another twelve mice, with a randomized crossover sequence of three drug treatments:DA-9701 3 mg/kg, erythromycin 6 mg/kg, or saline. Each breath test was performed at an interval of one week. RESULTS:Repeatedly measured half gastric emptying time of ten mice without drug treatment showed 0.856 of the intraclass correlation coefficient for the half gastric emptying time (P = 0.004). The mean cumulative excretion curve for the 13C-octanoic acid breath test showed accelerated gastric emptying after DA-9701 treatment compared with the saline control (P = 0.028). The median half gastric emptying time after the DA-9701 treatment was significantly shorter than after the saline treatment [122.4 min (109.0-137.9 min) vs 134.5 min (128.4-167.0 min), respectively; P = 0.028] and similar to that after the erythromycin treatment [123.3 min (112.9-138.2 min)]. The lag phase, which was defined as the period taken to empty 15% of a meal, was significantly shorter after the DA-9701 treatment than after the saline treatment [48.1 min (44.6-57.1 min) vs 52.6 min (49.45-57.4 min), respectively; P = 0.049]. CONCLUSION:The novel prokinetic agent DA-9701 accelerated gastric emptying, assessed with repeated measurements in the same mouse     

A valid, accurate, office based non-radioactive test for gastric emptying of solids

BACKGROUND: Current breath tests for measurement of gastric emptying of solids are expensive, possibly inaccurate, and require cumbersome calculations. AIMS: We wished to validate a simplified solid gastric emptying test using a [(13)C]Spirulina platensis breath test for accurate results relative to scintigraphy. SUBJECTS: Thirty healthy volunteers. METHODS: We measured gastric emptying of egg containing [(13)C]S platensis and (99m)Tc sulphur colloid by breath (13)CO(2) and scintigraphy over six hours. A generalised linear regression model was used to predict t(1/2) and t(LAG) by scintigraphy from breath (13)CO(2) data. The model was cross validated and normative data calculated for a prepacked [(13)C]meal. RESULTS: Regression models using all breath data over six hours, for the first three hours, and for samples at 75, 90, and 180 minutes ("reduced model") predicted t(1/2) and t(LAG) values similar to scintigraphy (t(LAG) 43 (SD 12) min; t(1/2) 100 (20) min). Standard deviations of differences in t(1/2) and t(LAG) between scintigraphy and the "reduced model" were both 10 minutes. Gastric t(1/2) for the prepacked [(13)C]meal was 91 (15) min (10-90% range: 74-118). CONCLUSION: The [(13)C]S platensis breath test and a simple formula using breath (13)CO(2) at baseline, 90, and 180 minutes measured gastric emptying t(1/2) for solids with results that were comparable with scintigraphy.     

Delayed gastric emptying in the obese: an assessment using the non-invasive (13)C-octanoic acid breath test

AIM: Much of the controversy surrounding the correlation between obesity and gastric emptying lies in the inconsistency of methodology and analysis. This study was designed to overcome some of the discrepancies encountered in previous studies and to test the hypothesis that obese individuals have altered gastric emptying compared to lean individuals. METHODS: Gastric emptying was measured using the (13)C-octanoic acid breath test in 16 lean and 16 obese women pair-matched for age. Following an overnight fast, subjects were given a standard 2 MJ egg meal labelled with 100 microl of [1-(13)C]-octanoic acid. Breath samples were collected at regular intervals over a 6-h period. (13)C-isotopic enrichment in the breath was analysed using isotope ratio mass spectrometry and the data fitted to the established gastric emptying model. The lag times (t(lag)), half excretion times (t(1/2)), latency phase (t(lat)) and ascension times (t(asc)) were calculated. RESULTS: The mean t(1/2)-values (+/-standard error of the mean) were 3.67 +/- 0.14 h and 4.23 +/- 0.18 h for lean and obese respectively, indicating significantly delayed gastric emptying in the obese (p = 0.019). The obese group also showed a significantly slower lag time (t(lag), p = 0.005) and latency phase (t(lat), p = 0.005), but no significant difference was found in the ascension time (t(asc), p = 0.154). Within groups, no correlation was found between half excretion times and body weight or half excretion times and body mass index. CONCLUSIONS: The present study demonstrated a prolonged lag phase and delayed gastric emptying in obese women when compared to lean women. This delay may be as a consequence of high-fat diets, a sedentary lifestyle and increased gastric distension associated with obesity, or a contributing factor in the pathogenesis of obesity resulting from the inactivation of gastrointestinal satiety signals and in an increase in food intake.     

Gastric emptying of a solid meal starts during meal ingestion: combined study using 13C-octanoic acid breath test and Doppler ultrasonography. Absence of a lag phase in 13C-octanoic acid breath test

Scintigraphy and the 13C-octanoic acid breath test are both applied to assess gastric emptying. Using the 13C-octanoic acid breath test, excretion curves show 13C excretion immediately after ingestion of a solid egg meal, in contrast with scintigraphy where gastric emptying is observed after a lag phase. The aim of our study was to investigate whether transpyloric flow occurs during and directly after meal ingestion. Therefore, transpyloric flow was measured during and after ingestion of an egg meal labeled with 13C-octanoic acid, using Doppler ultrasonography. The breath test was performed simultaneously, with samples taken at regular intervals. The first emptying episode was observed 6.9 (3.9-16.2) min after start of meal ingestion. A significant relation between recovery of 13C and total duration of gastric emptying during the first 20 min was observed (partial correlation coefficient r = 0.80, p < 0.001). In conclusion, transpyloric flow starts during ingestion of a solid egg meal and results in detectable excretion of 13C.     

Influence of acid suppressants on gastric emptying: cross-over analysis in healthy volunteers

BACKGROUND: Gastric emptying plays an important role in gastroesophageal reflux disease. Acid suppressants such as H2 receptor antagonists and/or proton pump inhibitors are often used in patients with gastroesophageal reflux disease. However, it remains controversial whether H2 receptor antagonists and proton pump inhibitors delay or accelerate gastric emptying. Here, the influence of acid suppressants on gastric emptying was evaluated via a cross-over study using the [13C]-labeled acetate breath test. METHODS: Twenty normal male subjects without gastroesophageal reflux disease symptoms were enrolled. Gastric emptying was investigated five times in every subject by the [13C]-labeled acetate breath test with oral administration of the vehicle, domperidone, and three acid suppressants: ranitidine, famotidine and rabeprazole. Gastric emptying was estimated by the values of T(max-calc), T(1/2) and %dose/2 h calculated from the 13CO2 breath excretion curve. RESULTS: Using the T(max-calc) values, rabeprazole, ranitidine and famotidine did not influence gastric emptying time in comparison with vehicle administration. Using the T(1/2) and %dose/2 h values, rabeprazole tended to delay gastric emptying. Domperidone produced a statistically significant acceleration of gastric emptying for all three variables (P < 0.05). CONCLUSION: Oral dosage of the H2 receptor antagonists, ranitidine and famotidine, has no significant effect on gastric emptying. However, rabeprazole may delay gastric emptying more strongly than H2 receptor antagonists.     

Evaluation of Gastric Emptying Measured with the 13 C-octanoic Acid Breath Test in Patients with Functional Dyspepsia: Comparison with Ultrasonography

Background: As a non-invasive modality by which to evaluate the gastric emptying of a solid meal, the 13C-octanoic acid breath test has recently become more widely used. Previously, we reported that ultrasonography was another non-invasive and reliable method for assessing gastric motility. The aim of this study was to compare the reliability of these two methods. Methods: Seventeen patients with functional dyspepsia and 10 healthy volunteers were studied. The solid test meal consisted of a scrambled egg labeled with 13 C-octanoic acid (100 mg) and served with a bowl of rice and boiled chicken (total 424 kcal). After ingestion of the test meal, all subjects were examined in the sitting position. Ultrasonography images were obtained every 15 min for 3 h. Breath sampling followed the same time schedule as for the ultrasonography, with an additional 3 h of sampling at 30-min intervals. We investigated the half emptying time (T1/2) and the lag phase with both methods. Results: The T1/2 by the ultrasonography method and the breath test were positively correlated ( r 2 = 0.638); however, there was no significant agreement between the study groups. Both the T1/2 and the lag phase were prolonged in the functional dyspepsia patients compared with the healthy volunteers, regardless of the method of measurement. The lag phase was significantly correlated ( r 2 = 0.864) with the T1/2 by the breath test. Conclusions: Although the 13 C-octanoic acid breath test cannot assess the gastric emptying of solids as reliably as ultrasonography, both tests are useful for evaluating functional dyspepsia patients with delayed gastric emptying.     

Evaluation of gastric emptying measured with the 13C-octanoic acid breath test in patients with functional dyspepsia: comparison with ultrasonography

BACKGROUND: As a non-invasive modality by which to evaluate the gastric emptying of a solid meal, the 13C-octanoic acid breath test has recently become more widely used. Previously, we reported that ultrasonography was another non-invasive and reliable method for assessing gastric motility. The aim of this study was to compare the reliability of these two methods. METHODS: Seventeen patients with functional dyspepsia and 10 healthy volunteers were studied. The solid test meal consisted of a scrambled egg labeled with 13C-octanoic acid (100 mg) and served with a bowl of rice and boiled chicken (total 424 kcal). After ingestion of the test meal, all subjects were examined in the sitting position. Ultrasonography images were obtained every 15 min for 3 h. Breath sampling followed the same time schedule as for the ultrasonography, with an additional 3 h of sampling at 30-min intervals. We investigated the half emptying time (T1/2) and the lag phase with both methods. RESULTS: The T1/2 by the ultrasonography method and the breath test were positively correlated (r2 = 0.638); however, there was no significant agreement between the study groups. Both the T1/2 and the lag phase were prolonged in the functional dyspepsia patients compared with the healthy volunteers, regardless of the method of measurement. The lag phase was significantly correlated (r2=0.864) with the T1/2 by the breath test. CONCLUSIONS: Although the 13C-octanoic acid breath test cannot assess the gastric emptying of solids as reliably as ultrasonography, both tests are useful for evaluating functional dyspepsia patients with delayed gastric emptying.     

Measuring gastric emptying of semisolids in children using the 13C-acetate breath test: a validation study.

BACKGROUND AND AIM: Radioscintigraphy is the gold standard for evaluation of gastric emptying in children, but requires exposure to ionising radiation. Therefore, the aim of the study was to validate the non-radioactive 13C-acetate breath test in children in comparison to radioscintigraphy as reference method. PATIENTS: Twenty-nine children with dyspeptic or respiratory symptoms were tested for gastric emptying disorders simultaneously performing the 13C-acetate breath test and radioscintigraphy. METHODS: A semisolid oatmeal was doubly labelled with 150 mg 13C-acetate and 50 MBq 99mTechnetium. Breath samples were collected every 5-10 min for 4 h. After mass spectrometrical 13C-analysis, curve fitting of the 13C-cumulative recovery to the modified power exponential function Y = m(1 - e(-kt) calculated the half emptying times of the breath test (t 1/2 (breath)). Scintigraphic image acquisition began immediately after the ingestion of the 99mTechnetium-labelled testmeal at a rate of one frame every 60 s for 1 h. RESULTS: Six children showed delayed gastric emptying in scintigraphy (t 1/2(scinti) > 60 min). All these children had prolonged half emptying times t 1/2 (breath) in the 13C-acetate breath test. Using a cut-off t 1/2(breath) > 90 min, the 13C-acetate breath test had a sensitivity of 100% and a specificity of 85%. Scintigraphic and breath test half emptying times were linearly correlated (Y = 0.80x + 47.68, r = 0.76, P < 0.00001). CONCLUSIONS: The 13C-acetate breath test proves to be a reliable, non-radioactive alternative for measuring gastric emptying in children.     

Gastric dysmotility after liquid bolus ingestion in systemic sclerosis: an ultrasonographic study

Gastric involvement appears quite commonly in systemic sclerosis (SSc). The aim of this study was to evaluate gastric wall motility using ultrasonography, a noninvasive method able to track both filling and emptying of fundus and antrum. The study was performed in 20 SSc patients and 20 healthy control subjects. Gastric filling and emptying were evaluated by transabdominal ultrasonography, measuring changes in fundus and antral areas over a 1-h period after ingestion of a liquid bolus (500 ml of mineral water). Areas of both gastric fundus and antrum at basal evaluation were found to be smaller in SSc patients than in healthy controls. Gastric filling was significantly reduced after ingestion of liquid bolus. Gastric emptying was delayed both in fundus and antrum. No significant differences of gastric wall motility have been observed in different subsets of SSc patients. Our findings show that gastric dysmotility is frequent and severe in SSc patients, contributing to the gastrointestinal disturbances which are very common in this disease.     

Effects of Helicobacter pylori eradication therapy on gastric emptying measured using the 13C-octanoic acid breath test and the acetaminophen method

BACKGROUND: The relationship between Helicobacter pylori eradication and gastric emptying has been reported; however, the effect of eradication therapy on gastric emptying is still unclear. This study evaluated the relationship between three gastric emptying techniques, the scintigraphic technique, the 13C-octanoic acid breath test, and the acetaminophen method, measured simultaneously, and the effect of H. pylori eradication therapy on gastric emptying and abdominal symptoms in patients with functional dyspepsia who were H. pylori positive. METHODS: Fifty-three consecutive patients with positive H. pylori infection were enrolled in this study. In the first 14 patients, gastric emptying was measured using the three gastric emptying techniques. In 42 patients cured of H. pylori infection, the 13C-octanoic acid breath test and the acetaminophen method were performed before and 3 months after eradication. RESULTS: Significant correlations were found between the scintigraphic technique, the 13C-octanoic acid breath test, and the acetaminophen method. Gastric emptying determined by the 13C-octanoic acid breath test and the acetaminophen method was not changed after eradication, on average. In 14 (33.3%) patients a decrease in symptom score after eradication was observed. In four (9.5%) patients, accelerated gastric emptying after eradication may have led to a reduction in the abdominal symptoms. CONCLUSIONS: The 13C-octanoic acid breath test and the acetaminophen method are appropriate for investigating gastric emptying. A causal relationship between improvement of symptoms and accelerated gastric emptying was not found, and the efficacy of H. pylori eradication therapy in patients with functional dyspepsia was minimally exhibited.     

Pharmacological modulation of gastric emptying rate of solids as measured by the carbon labelled octanoic acid breath test: influence of erythromycin and propantheline.

The *C (13C or 14C) labelled octanoic acid breath test was recently developed to measure the gastric emptying rate of solids. This study aimed to investigate whether it is sensitive enough to detect pharmacologically induced changes in the gastric emptying rate. Nine healthy volunteers were studied in basal condition, after intravenous administration of 200 mg erythromycin, and after peroral administration of 30 mg propantheline. Erythromycin significantly enhanced gastric emptying in all subjects, with an increase of the gastric emptying coefficient (p = 0.0043) in eight of nine and a fall in both the gastric half emptying time (p = 0.0020) and the lag phase (p = 0.0044) in all nine. Propantheline significantly reduced the gastric emptying rate, with a decreased gastric emptying coefficient (p = 0.0007) and an increased gastric half emptying time (p = 0.0168) in all subjects, but no change in the lag phase (p = 0.1214). Further mathematical analysis showed that breath sampling at 15 minutes intervals over a four hour period is recommended to guarantee accuracy and the discriminative value of the breath test in various gastric emptying patterns. In conclusion the *C labelled octanoic acid breath test is sufficiently sensitive to show pharmacologically induced changes of gastric emptying rates of solids.