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PubMed2002

Reproducibility of derived central arterial waveforms in patients with chronic renal failure.

Arterial stiffness potently predicts mortality in dialysis patients. Pulse-wave analysis permits the non-invasive assessment of indices of arterial stiffness and the central pressure waveform by applanation tonometry. The aim of this study was to assess the reproducibility of pulse-wave analysis in patients with chronic renal failure. A total of 188 subjects (23 healthy controls, along with 71 pre-dialysis, 67 dialysis and 27 transplant patients) took part. Duplicate measurements were recorded of brachial blood pressure using the semi-automated Omron 705 device and of the radial artery pressure waveform using applanation tonometry. The central pressure aortic waveform was then obtained by application of a transfer function incorporated into the SphygmoCor software. Central aortic mean blood pressure (MBP), indices of arterial stiffness [augmentation index (AIx) and time to reflection (TR)] and the subendocardial viability ratio (SEVR) were analysed for intra-observer, inter-observer and long-term reproducibility using Bland-Altman plots. The mean (+/-S.D.) intra-observer difference was 0+/-4% for AIx, 0+/-20 ms for TR, 0+/-3 mmHg for aortic MBP and 0+/-18% for the SEVR. Inter-observer mean differences were 0+/-3% for AIx, 1+/-7 ms for TR, 1+/-4 mmHg for aortic MBP and 1+/-9% for the SEVR. For the long-term study, the mean differences were -1+/-9% for AIx, -2+/-13 mmHg for aortic MBP, -2+/-12 ms for TR and 1+/-29% for the SEVR. Pulse-wave analysis showed excellent reproducibility in all the studies, and is therefore suitable for use in all patients with chronic renal failure. Further prospective and interventional studies are now required to assess whether AIx and TR are important prognostic indices of cardiovascular events, and therefore relevant surrogate indices of arterial stiffness in this susceptible population.

Adult↗

PubMed2006

Reproducibility of cephalometric measurements made by three radiology clinics.

The purpose of this study was to assess reproducibility of cephalometric measurements in cephalograms obtained by three dentomaxillofacial radiology clinics. Forty lateral cephalometric radiographs were selected and sent at different times to three different clinics for cephalometric analyses. Each clinic digitized the radiographs with the same resolution, and landmarks were located with the mouse pointer directly on the digitized radiographic image on the screen. Three cephalograms were obtained from each radiograph, totaling 120 analyses. Data were analyzed with analysis of variance. Of the 32 factors studied, reproducibility of results was satisfactory for only four factors: position of maxilla relative to anterior cranial base, inclination of occlusal plane relative to anterior cranial base, position of lower incisor relative to nasion-pogonion line, and soft-tissue profile of face (P < .05). Differences in cephalometric measurements were present and such differences were significant for most factors analyzed. The different cephalometric measurements obtained by the three dental radiology clinics were not reproducible.

Cephalometry↗

PubMed2001

Reproducibility and repeatability of transabdominal uterine artery Doppler velocimetry between 10 and 14 weeks of gestation.

OBJECTIVE: To assess the intraobserver repeatability and interobserver reproducibility of Doppler flow velocity measurements of the uterine arteries in pregnant women between 10 and 14 weeks of gestation. METHODS: In this prospective study, Doppler velocimetric indices (maximum peak systolic velocity, end-diastolic velocity, peak systolic velocity/end-diastolic velocity ratio, pulsatility index and resistance index) were measured twice by the same trained observer in each uterine artery of 63 women. In 47 of these women, a second trained observer then repeated the measurements. In addition, both observers classified qualitatively the blood flow with regard to the presence or absence of an early diastolic notch. The coefficient of variation, intraclass correlation coefficients, within observer and between observers repeatability coefficient and Cohen's kappa coefficient were calculated. RESULTS: The best parameter in terms of repeatability and reproducibility in both uterine arteries was the resistance index with a low coefficient of variation and high intraclass correlation coefficient. The other parameters (pulsatility index, peak systolic velocity/end-diastolic velocity ratio, peak systolic velocity and end-diastolic velocity) performed poorly with high coefficients of variation on both sides. Agreement between the repeated observations (inter- and intraobserver) with regard to the presence or absence of an early diastolic notch was good. CONCLUSION: Doppler velocimetry of uterine artery blood flow is technically feasible between 10 and 14 weeks of gestation. This study demonstrates that this technique is prone to measurement errors. Quantitatively, the resistance index appears to be the most repeatable and reproducible measurement at this gestational age. Qualitative assessment of the waveform morphology also shows high levels of intra- and interobserver agreement.

Adult↗

PubMed2002

Reproducibility of transvaginal three-dimensional endometrial volume measurements with virtual organ computer-aided analysis (VOCAL) during ovarian stimulation.

OBJECTIVE: To calculate inter- and intraobserver reliabilities for three-dimensional endometrial volume measurements during in vitro fertilization using virtual organ computer-aided analysis (VOCAL). PATIENTS AND METHODS: Three-dimensional ultrasound measurements of the endometrium using VOCAL software were performed on the day of oocyte retrieval in each of 79 consecutive patients undergoing in vitro fertilization or intracytoplasmic sperm injection. Endometrial volume was calculated every 15 degrees and every 30 degrees by two different observers in order to determine the reproducibility of the technique. RESULTS: Intraobserver reliability for the 15 degrees measurements was 0.97 for both observers; for the 30 degrees measurements, it was 0.93 for one observer and 0.96 for the other. Interobserver reliability was 0.80 for the endometrial volumes calculated every 15 degrees and 0.83 for the volumes calculated every 30 degrees. The intra- and interobserver measurement agreement showed good reproducibility. However, the volumes calculated every 15 degrees were more accurate because the means of differences were close to zero. CONCLUSION: VOCAL provides a reproducible method for the estimation of the endometrial volume.

Adult↗

PubMed2002

The reproducibility of endometrial volume acquisition and measurement with the VOCAL-imaging program.

OBJECTIVES: To determine the intraobserver reproducibility of volume acquisition and repeatability of endometrial volume measurements using the VOCAL-imaging program (Virtual Organ Computer-aided AnaLysis). METHODS: Ten three-dimensional (3D) ultrasound datasets of the same endometrium were obtained from one patient during one scan session. For every 3D dataset, the endometrial volume was calculated by four different measurement techniques; three rotational methods and one conventional method. A single observer acquired each dataset and conducted all measurements. For the rotational technique, the manual mode was used to trace the myometrial-endometrial border through three different predefined rotations of 30 degrees, 15 degrees and 9 degrees . Endometrial volume was also measured in a conventional manner by scrolling through one of the multiplanar images and outlining the contour in another. Ten consecutive measurements were taken for each of the four measurement techniques so that 40 endometrial volume readings were obtained for each of the 10 3D-ultrasound datasets. RESULTS: Endometrial volume measurements were more reproducible with the rotational technique. Rotational methods employing a rotation step of less than 30 degrees were associated with coefficients of variation below 1% and intraclass correlation coefficients above 0.94. Within each of the 10 different scans, the homogeneity of the variance of measurements was significantly different according to the method of measurement (P = 0.022 to < 0.001). Post-hoc tests revealed that both the conventional and 30 degrees rotational methods resulted in a significantly smaller mean endometrial volume than both the 15 degrees and the 9 degrees rotational methods. CONCLUSIONS: Endometrial volume acquisition is reproducible and endometrial volume measurements are repeatable but they depend upon the technique of volume calculation in so much as rotational methods employing a rotation step of less than 30 degrees are associated with a significantly smaller variance in measurements and a significantly greater mean endometrial volume.

Adult↗

PubMed1997

Intra-arterial substance P mediated vasodilatation in the human forearm: pharmacology, reproducibility and tolerability.

AIMS: The current studies were designed to characterize the pharmacology, reproducibility and tolerability of the vasodilator response to intra-arterial substance P infusion in the forearm of healthy man. METHODS: On different occasions, eight healthy male volunteers received brachial artery infusions of substance P at doubling doses ranging from 0.5 to 128 pmol min(-1). Blood flow was measured in both arms using venous occlusion plethysmography. RESULTS: Substance P induced dose-dependent vasodilatation in the human forearm which had a log-linear relationship to dose. At doses of 1-8 pmol min(-1), mean responses were highly reproducible both within and between days. There were no differences between responses to discontinuous doses and continuous doses of substance P. Substance P was generally well tolerated at doses of < or = 64 pmol min(-1) with no significant alteration in arterial blood pressure or heart rate. Skin oedema in the infused forearm and systemic vasodilatation, manifested by facial flushing and non-infused forearm vasodilatation, occurred at doses of > or = 16 pmol min(-1). CONCLUSIONS: Forearm vasodilatation to substance P represents a reproducible and useful model in the assessment of peripheral endothelial cell NK1 receptor function.

Adult↗

PubMed1999

Reproducibility of the cortisol response to stimulation with the low dose (1 microg) of ACTH.

OBJECTIVE: Previous studies have shown that the rapid ACTH stimulation test using a low dose of 1 microg is more sensitive than that using 250 microg ACTH for detecting subtle cases of adrenal insufficiency. However, there are controversies for the reproducibility of the 1 microg-test. To evaluate the reproducibility of the 1 microg-test, we assessed both day-to-day and diurnal variations of cortisol responses to 1 microg ACTH injection. In addition, optimum sampling time for the 1 microg-test was also determined. SUBJECTS: AND DESIGN Eight healthy volunteers and five patients with secondary adrenal insufficiency were recruited. Healthy subjects were given 1 microg ACTH 3 times in the morning (0800 h) and 2 times in the afternoon (1600 h). Patients with adrenal insufficiency had 2-tests in the morning and 2 in the afternoon. Serum cortisol levels were measured every 10 minutes for 1 h after the injection. RESULTS: In healthy subjects, basal and peak serum cortisol levels were significantly higher in the morning (P < 0.05), whereas maximum cortisol increments were higher in the afternoon (P < 0.001). In patients with adrenal insufficiency, basal and peak serum cortisol levels in the morning were not different from corresponding values in the afternoon. Intra-individual coefficient of variation (CV) of peak serum cortisol response to 1 microg ACTH ranged from 3.0 to 16.4% in healthy subjects and 10.0-34. 4% in patients. Also, there was a significant correlation between peak morning or afternoon cortisol levels after 1 microg ACTH injection given in different days in both healthy subjects and patients. Twenty-six of the 40 studies in healthy subjects showed peak response at 20 minutes, while nine showed it at 30 minutes Using the data acquired at 20 and 30 minutes, all 40 studies in healthy subjects showed normal results while none of 20 studies in patients was normal. CONCLUSIONS: We conclude that the cortisol response to 1 microg ACTH stimulation was reproducible in both healthy subjects and patients with secondary adrenal insufficiency. In order to assess adrenal function more accurately with the 1 microg ACTH stimulation test, serum cortisol should be measured before and 20 and 30 minutes after ACTH injection.

Adrenal Cortex Diseases↗

PubMed1998

Poor reproducibility of exercise test in assessment of claudication.

To assess reproducibility of the exercise test in intermittent claudication, a prospective, comparative, randomized study was undertaken. Ten patients with stable intermittent claudication of ischaemic origin were exercised on a flat surface (0-Ex), with 12% steady inclination (12-Ex) and with progressively increasing inclination (p-Ex) in a random order during three different sessions. The ankle-brachial index (ABI) at rest and after exercise (rABI, exABI), initial and maximum walking distance (IWD, MWD) and metabolic equivalent (MET) were obtained as the main outcome measures. The results were analysed using intraindividual coefficients of variation (CVs) and standard deviations (SDs). The ABI values of the worst extremity were used in evaluation of results. Reproducibility of the exercise ABI appeared to be good, especially during progressively increasing exercise, the mean CV being 9 +/- 5%. The best mean CV was observed during p-Ex (16% +/- 14%) for maximum walking distance. The mean CV for initial walking distances ranged from 30% to 54%. Treadmill exercise testing to measure walking distances is highly inaccurate and the value of exercise on the flat treadmill should be questioned. Graded exercise appeared to be the most reproducible in this respect. The ABI after exercise, however, was a reliable single parameter when assessing arterial insufficiency causing decreased walking capacity.

Aged↗

PubMed2001

The insulin hypoglycemia test: hypoglycemic criteria and reproducibility.

The insulin hypoglycemia test (IHT) is widely regarded as the "gold standard" for dynamic stimulation of the hypothalamic-pituitary-adrenal (HPA) axis. This study aimed to investigate the temporal relationship between a rapid decrease in plasma glucose and the corresponding rise in plasma adenocorticotropic hormone (ACTH), and to assess the reproducibility of hormone responses to hypoglycemia in normal humans. Ten normal subjects underwent IHTs, using an insulin dose of 0.15 U/kg. Of these, eight had a second IHT (IHT2) and three went on to a third test (IHT3). Plasma ACTH and cortisol were measured at 15-min intervals and, additionally, in four IHT2s and the three IHT3s, ACTH was measured at 2.5- or 5-min intervals. Mean glucose nadirs and mean ACTH and cortisol responses were not significantly different between IHT1, IHT2 and IHT3. Combined data from all 21 tests showed the magnitude of the cortisol responses, but not the ACTH responses, correlated significantly with the depth and duration of hypoglycemia. All subjects achieved glucose concentrations of of < or = 1.6 mmol/l before any detectable rise in ACTH occurred. In the seven tests performed with frequent sampling, an ACTH rise never preceded the glucose nadir, but occurred at the nadir, or up to 15 min after. On repeat testing, peak ACTH levels varied markedly within individuals, whereas peak cortisol levels were more reproducible (mean coefficient of variation 7%). In conclusion, hypoglycemia of < or = 1.6 mmol/l was sufficient to cause stimulation of the HPA axis in all 21 IHTs conducted in normal subjects. Nonetheless, our data cannot reveal whether higher glucose nadirs would stimulate increased HPA axis activity in all subjects. Overall, the cortisol response to hypoglycemia is more reproducible than the ACTH response but, in an individual subject, the difference in peak cortisol between two IHTs may exceed 100 nmol/l.

Adrenal Glands↗

PubMed1998

An evaluation of RAPD fragment reproducibility and nature.

Random amplified polymorphic DNA (RAPD) fragment reproducibility was assayed in three animal species: red deer (Cervus elaphus), wild boar (Sus scrofa) and fruit fly (Drosophila melanogaster). Ten 10-mer primers (Operon) were tested in two replicate reactions per individual under different stringency conditions (annealing temperatures of 35 degrees C or 45 degrees C). Two estimates were generated from the data: autosimilarity, which tests the reproducibility of overall banding patterns, and band repeatability, which tests the reproducibility of specific bands. Autosimilarity (the similarity of individuals with themselves) was lower than 1 for all three species ranging between values of 0.66 for Drosophila at 45 degrees C and 0.88 for wild boar at 35 degrees C. Band repeatability was estimated as the proportion of individuals showing homologous bands in both replicates. The fraction of repeatable bands was 23% for deer, 36% for boar and 26% for fruit fly, all at an annealing temperature of 35 degrees C. Raising the annealing temperature did not improve repeatability. Phage lambda DNA was subjected to amplification and the pattern of bands compared with theoretical expectations based on nucleotide sequence. Observed fragments could not be related to expected ones, even if a 2 bp mismatch is allowed. Therefore, the nature of genetic variation uncovered by the RAPD method is unclear. These data demonstrate that prudence should guide inferences about population structure and nucleotide divergence based on RAPD markers.

Animals↗

PubMed2001

Reproducibility of antroduodenal motility during prolonged ambulatory recording.

Ambulatory recording of antroduodenal manometry is a novel technique with several advantages over standard stationary manometry recording. Although the feasibility of this technique in clinical practice has been demonstrated, reproducibility of antroduodenal motility recorded by means of ambulatory manometry has not been investigated. To test whether antroduodenal motility recorded by ambulatory manometry is reproducible, we performed two 24-h ambulatory antroduodenal manometry recordings in 18 healthy subjects according to an identical protocol with a 1-week interval. Motility was recorded with a five-channel solid-state catheter. Postprandial motility was recorded after consumption of two test meals and interdigestive motility was recorded nocturnally. Postprandial antroduodenal motor characteristics were identical between the separate recordings. The number and duration of nocturnal cycles of the interdigestive migrating motor complex were also in the same range. Phase III characteristics in general were not different between the two recordings. Only minor alterations were observed in the duration of phase III motor fronts with duodenal onset and in the number of interdigestive cycles concluded by duodenal onset phase III. Parameters obtained by qualitative analysis were comparable between the two recordings. The antroduodenal motility pattern, when measured by ambulatory recording with solid state catheters under standardized conditions, is very reproducible.

Adult↗

PubMed2002

The immediate reproducibility of T wave alternans during bicycle exercise.

A number of recent studies have demonstrated that the microvolt level T wave alternans measured during bicycle exercise can identify patients at high risk for developing malignant ventricular arrhythmias. However, little is known about the reproducibility of T wave alternans measured during bicycle exercise. The purpose of this study was to prospectively evaluate the immediate reproducibility of T wave alternans measured during bicycle exercise testing. Thirty-five patients with congestive heart failure underwent two sequential bicycle exercise tests with the measurement of T wave alternans. The T wave alternans tests were randomly sorted and then classified by two readers who were blinded to the patient and the sequence of the two tests. Tests were classified as determinate (positive or negative) or indeterminate according to previously published criteria. Of the 22 patients that had two determinate T wave alternans tests, 18 (82%) of 22 patients had concordant test results (kappa 0.58). Of the four patients who had discordant test results on the two tests, three patients had one test that was borderline and difficult to interpret. One patient had two sequential tests that were clearly different. Of the ten patients whose initial test was indeterminate, five became determinate on the second test. T wave alternans measured during bicycle exercise has an acceptable reproducibility when measurements are madefrom two sequential exercise tests performed within a short period. This data suggests that the measurement of T wave alternans during exercise is reliable. Repeating the exercise test with a second measure of T wave alternans during the same session can significantly reduce the proportion of patients with indeterminate test results.

Electrocardiography↗

PubMed2003

Flecainide test in Brugada syndrome: a reproducible but risky tool.

The flecainide test is widely used in Brugada syndrome. However, its reproducibility and safety remain ill-defined. This study included 22 patients (18 men, mean age 34 years). Mutations in the SCN5A gene were found in eight patients. Two patients had aborted sudden cardiac death, 8 had syncope/presyncope, and 12 were asymptomatic. The ECG was diagnostic in 19 patients and suggestive in 3. At baseline, 21 of 22 patients underwent a flecainide test (2 mg/kg IV bolus over 10 minutes). In 21 of 21 patients the test was diagnostic or amplified the typical ECG pattern. At the end of drug infusion, sustained VT lasting 7-10 minutes developed in two patients. A second flecainide test was performed within 2 months in 20 patients. The test was not repeated in the two patients with prior development of VT. The flecainide test was diagnostic in 20 of 20 patients. Sustained VT occurred in one patient and recurrent VF in another. The reproducibility of the flecainide test was 100%. In 4 (18%) of 22 patients major VAs were documented after the end of flecainide infusion. VA occurred in 3 (43%) of 7 patients with, versus 1 (7%) 15 without SCN5A gene mutation (P < 0.05). No diagnostic ECG changes or arrhythmias developed in 25 control patients without structural heart disease who underwent the same study protocol. This study shows a high flecainide reproducibility, supporting its diagnostic value in Brugada syndrome. However, the occurrence of major VA, significantly higher in patients with documented SCN5A gene mutation, including in asymptomatic patients, mandates the performance under appropriate medical supervision. Whether a slower rate of drug infusion can lower the risk of VA induction, while maintaining the sensitivity of the test should be explored.

Adolescent↗

PubMed1996

Reproducibility of penile arterial colour duplex ultrasonography.

OBJECTIVE: To assess the reproducibility of penile arterial colour duplex ultrasonography (CDU) in patients with impotence. PATIENTS AND METHODS: Fifty-eight patients underwent CDU of their penile arteries on two occasions 2 weeks apart. Group A (n = 34) received 60 mg of papaverine intracavernosally before CDU and group B (n = 24) received a combination of papaverine, prostaglandin E1 and phentolamine. The variables measured during CDU were peak systolic velocity (PSV) and the end diastolic velocity (EDV), with the systolic rise-time (SRT) also recorded in group B. RESULTS: In both groups of patients the reproducibility between the first and second recordings was poor for all variables. The mean variation in PSV was 31.5% and 40.2%, and in EDV was 44.9% and 50.1%, for groups A and B, respectively. For the SRT, measured only in group B, the mean variation was 25.7%. CONCLUSIONS: These results show that CDU is a poorly reproducible technique for assessing vascular status in patients with impotence. Therefore, it is not reliable in the long-term follow-up of patients and single measurements should be interpreted with caution.

Adult↗

PubMed2002

Intraobserver and interobserver reproducibility of ultrasound measurements of endometrial thickness in postmenopausal women.

OBJECTIVES: To determine intraobserver and interobserver reproducibility of ultrasound measurements of endometrial thickness in postmenopausal women. DESIGN: Forty-eight postmenopausal women underwent transvaginal ultrasound examination by two examiners. Each observer took three replicate measurements of the endometrium in each woman. Intraobserver repeatability was expressed as the difference between the highest and lowest measurement values obtained by one observer, the repeatability coefficient, and the intraclass correlation coefficient. Interobserver reproducibility was expressed as the difference between the mean of the three measurements of each observer, limits of agreement, and interclass correlation coefficient. The repeatability coefficient and the limits of agreement define the range within which 95% of the differences between two measurements are likely to fall. Data were analyzed for all women, as well as separately for women with endometrium < or = 6 mm and > 6 mm. The agreement between observers in classifying women as having endometrium < or = 4.4 mm or > or= 4.5 mm was determined by calculating Cohen's kappa. RESULTS: In women with endometrium 6 mm were 0.99 and 0.99, 0.7 mm (0-2.9) and 1.0 mm (0.2-3.4), and 1.7 mm and 1.9 mm. In women with endometrium < or = 6 mm the interclass correlation coefficient was 0.77, and the mean interobserver difference was 0.2 mm +/- 1.8 mm (2 standard deviations), when calculations were based on the mean of three measurements per observer (+/- 1.9 mm when calculations were based on only one measurement per observer). The corresponding figures for women with endometrium > 6 mm were 0.98, 0.2 mm +/- 3.1 mm (+/- 3.2 mm). The agreement between observers in classifying women as having an endometrium < or = 4.4 mm or > or = 4.5 mm was very good (kappa 0.81). CONCLUSIONS: The reproducibility of endometrial measurements seems to be clinically acceptable and to allow reliable discrimination between postmenopausal women with endometrium < or = 4.4 mm and > or = 4.5 mm. In clinical practice, it is enough to take one endometrial measurement when performing transvaginal ultrasound examination.

Aged↗

PubMed2003

Assessment of reproducibility of measures of intraocular pressure and central corneal thickness in young white adults over a 16-h time period.

PURPOSE: The aims of this study were to obtain clinical measures of intraocular pressure (IOP) and central corneal thickness (CCT) and during waking hours to further assess both the nature of diurnal changes, and the reproducibility of any possible association between the two measures. METHODS: Fifteen white (Norwegian) healthy young adult subjects aged 20-29 years had IOP and CCT measures made, using a non-contact specular microscope and non-contact tonometry (NCT), every hour over a period of 16 h, starting at 06.30 hours. The experiment was repeated on two successive days. RESULTS: The average NCT readings were 12.5 and 11.4 mmHg for days 1 and 2, while pachometry averages were 0.518 and 0.514 mm. The range of NCT values, for any set of readings, averaged 2 mmHg, while this range was 0.014 mm for CCT measures. The reproducibility of these measures, as estimated by the coefficient of variation (COV) was 7.2% for NCT and 1.0% for pachometry measures. The COV for tonometry was inversely proportional to the actual values of these measures. A significant time-related decline in tonometry values was seen over day 1 but not day 2. Pachometry values declined very rapidly over the first hour in both sessions and were essentially constant for the rest of the sessions. The strongest association between pachometry data and NCT measures was noted around midday (12.30 hours) on both sessions. CONCLUSIONS: These studies confirm that the reproducibility (repeatability) of NCT and pachometry are substantially different. It is suggested that this aspect of tonometry needs to be taken into account, especially where there are lower values, when considering the possible impact of corneal thickness on tonometry measures and their interpretation. These types of effects need to be further assessed in older patients with ocular hypertension, or other glaucoma suspects.

Adult↗

PubMed2000

13C urea breath test with nondispersive isotope-selective infrared spectrometry: reproducibility and importance of the fasting status.

BACKGROUND: The 13C urea breath test (13C-UBT) is the most convenient method for diagnosing Helicobacter pylori infection noninvasively. Nondispersive isotope-selective infrared spectrometry (NDIRS) is an inexpensive and easy alternative to mass spectrometry. The objective of this study was to evaluate: (1) the reproducibility of the 13C-UBT as performed by using the NDIRS method; (2) the repeatability of bags analysis and the impact of delayed analysis; and (3) the need for fasting status for the 13C-UBT. METHODS: The 13C-UBT was performed with 75 mg urea labeled with 13C, with breath samples collected at times 0 and 30 minutes. Results are expressed as delta over baseline (0/00). Fifty-three patients underwent two successive 13C-UBTs with an interval of 48 to 72 hours. The 106 collected bags were randomly reanalyzed immediately or 72 hours later. In 26 volunteer subjects, the 13C-UBT was performed both in a fasting condition and after a nonstandardized meal. The reproducibility was assessed by the method of Bland and Altman. RESULTS: The mean of difference between two successive tests was 0. 14 0/00 (standard deviation, 0.90), and the coefficient of repeatability was 1.80 (confidence interval, 95%). The difference between two successive analyses was always less than 2.2% of the initial value. The coefficient of variation between two successive tests for the influence of a meal was 11.24. CONCLUSION: The 13C-UBT as performed by using NDIRS is reproducible, analyses can be delayed up to 72 hours, and the test must be performed in fasting conditions.

Breath Tests↗

PubMed2002

Reproducibility of blood pressure variation in older ambulatory and bedridden subjects.

OBJECTIVES: We investigated the influence of ambulation on the reproducibility of circadian blood pressure variation in older nursing home residents. DESIGN: Ambulatory blood pressure monitoring was performed twice in 37 older nursing home residents. SETTING: Nursing home in Japan. PARTICIPANTS: Subjects included 18 ambulatory nursing home residents who had no limitation on physical activity and 19 bedridden residents who did not participate in physical activity. MEASUREMENTS: Twenty-four-hour, daytime, and nighttime blood pressure levels and their variability. RESULTS: The 24-hour and daytime variability of systolic blood pressure (SBP) was significantly greater in ambulatory than in bedridden subjects, whereas nighttime variability was similar. Significant correlations in SBP averaged for the whole day, daytime, and nighttime were observed between the two examinations in ambulatory (r =.80-.83) and bedridden (r =.83-.91) subjects, but the variabilities of SBP for the whole day and during the daytime of the first measurement were correlated with those of the second measurement in bedridden (r =.67 and r =.47, respectively) but not in ambulatory (r =.39 and r =.28, respectively) subjects. Significant correlations were found between the nocturnal SBP changes at two occasions in both ambulatory (r =.50) and bedridden (r =.51) subjects, but the dipper versus nondipper profiles, defined as reduction in SBP of greater than 10% versus not, showed low reproducibility in ambulatory subjects; five ambulatory (28%) and one bedridden (5%) subjects showed divergent profiles between the two examinations. CONCLUSIONS: The reproducibility of blood pressure variation in nursing home residents is influenced by ambulation.

Aged↗