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Assessment of Tandem Measurements of pH and Total Gut Transit Time in Healthy Volunteers.

Mikolajczyk AE, Watson S, Surma BL, Rubin DT - Clin Transl Gastroenterol (2015)

Bottom Line: There was a significant change in pH for AIC (mean difference: -0.45±0.31, P=0.0015) observed across all subjects.This study demonstrates the safety and feasibility of tandem gut transit and pH assessments using the SmartPill device.In healthy individuals and over 24 h, the gut pH profile does not markedly fluctuate in a given region with more variation seen in the colon compared with the small bowel, which has important implications for future physiology and drug delivery studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, The University of Chicago Medicine, Chicago, Illinois, USA.

ABSTRACT

Objectives: The variation of luminal pH and transit time in an individual is unknown, yet is necessary to interpret single measurements. This study aimed to assess the intrasubject variability of gut pH and transit time in healthy volunteers using SmartPill devices (Covidien, Minneapolis, MN).

Methods: Each subject (n=10) ingested two SmartPill devices separated by 24 h. Mean pH values were calculated for 30 min after gastric emptying (AGE), before the ileocecal (BIC) valve, after the ileocecal (AIC) valve, and before body exit (BBE). Intrasubject variability was determined by comparing mean values from both ingestions for an individual subject using standard deviations, 95% limits of agreement, and Bland-Altman plots.

Results: Tandem device ingestion occurred without complication. The median (full range) intrasubject standard deviations for pH were 0.02 (0.0002-0.2048) for AGE, 0.06 (0.0002-0.3445) for BIC, 0.14 (0.0018-0.3042) for AIC, and 0.08 (0.0098-0.5202) for BBE. There was a significant change in pH for AIC (mean difference: -0.45±0.31, P=0.0015) observed across all subjects. The mean coefficients of variation for transit time were 12.0±7.4% and 25.8±15.8% for small and large bowels, respectively (P=0.01).

Conclusions: This study demonstrates the safety and feasibility of tandem gut transit and pH assessments using the SmartPill device. In healthy individuals and over 24 h, the gut pH profile does not markedly fluctuate in a given region with more variation seen in the colon compared with the small bowel, which has important implications for future physiology and drug delivery studies.

No MeSH data available.


Bland-Altman plots for the small and large bowel transit time values across the two ingestions for each patient. Solid and dashed lines represent mean and 95% confidence limits of the pairwise differences, respectively. There was no evidence of a linear relationship between transit time difference and magnitude.
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fig5: Bland-Altman plots for the small and large bowel transit time values across the two ingestions for each patient. Solid and dashed lines represent mean and 95% confidence limits of the pairwise differences, respectively. There was no evidence of a linear relationship between transit time difference and magnitude.

Mentions: The mean transit time across all 20 ingestions for the small bowel was 288.6±52.7 min (4.81 h), 1,210.2±873.7 min (20.17 h) for the large bowel, and 1667.3±871.46 min (27.8 h) for the entire gut, with median values of 295.5, 1,004.0, and 1,428.0, respectively. The mean coefficients of variation between the two ingestions for all 10 subjects were 12.0±7.4% for the small bowel, 25.8±15.8% for the large bowel (P=0.01), and 19.4±10.2% for the entire gut. Transit time coefficients of reliability in the small bowel, large bowel, and overall (87.57, 936.05, and 1,044.68, respectively) are quite large, suggesting that transit times significantly vary from 1 day to the next. There was no evidence of a linear relationship between transit time difference and magnitude in the Bland-Altman plots (Figure 5).


Assessment of Tandem Measurements of pH and Total Gut Transit Time in Healthy Volunteers.

Mikolajczyk AE, Watson S, Surma BL, Rubin DT - Clin Transl Gastroenterol (2015)

Bland-Altman plots for the small and large bowel transit time values across the two ingestions for each patient. Solid and dashed lines represent mean and 95% confidence limits of the pairwise differences, respectively. There was no evidence of a linear relationship between transit time difference and magnitude.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4816255&req=5

fig5: Bland-Altman plots for the small and large bowel transit time values across the two ingestions for each patient. Solid and dashed lines represent mean and 95% confidence limits of the pairwise differences, respectively. There was no evidence of a linear relationship between transit time difference and magnitude.
Mentions: The mean transit time across all 20 ingestions for the small bowel was 288.6±52.7 min (4.81 h), 1,210.2±873.7 min (20.17 h) for the large bowel, and 1667.3±871.46 min (27.8 h) for the entire gut, with median values of 295.5, 1,004.0, and 1,428.0, respectively. The mean coefficients of variation between the two ingestions for all 10 subjects were 12.0±7.4% for the small bowel, 25.8±15.8% for the large bowel (P=0.01), and 19.4±10.2% for the entire gut. Transit time coefficients of reliability in the small bowel, large bowel, and overall (87.57, 936.05, and 1,044.68, respectively) are quite large, suggesting that transit times significantly vary from 1 day to the next. There was no evidence of a linear relationship between transit time difference and magnitude in the Bland-Altman plots (Figure 5).

Bottom Line: There was a significant change in pH for AIC (mean difference: -0.45±0.31, P=0.0015) observed across all subjects.This study demonstrates the safety and feasibility of tandem gut transit and pH assessments using the SmartPill device.In healthy individuals and over 24 h, the gut pH profile does not markedly fluctuate in a given region with more variation seen in the colon compared with the small bowel, which has important implications for future physiology and drug delivery studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, The University of Chicago Medicine, Chicago, Illinois, USA.

ABSTRACT

Objectives: The variation of luminal pH and transit time in an individual is unknown, yet is necessary to interpret single measurements. This study aimed to assess the intrasubject variability of gut pH and transit time in healthy volunteers using SmartPill devices (Covidien, Minneapolis, MN).

Methods: Each subject (n=10) ingested two SmartPill devices separated by 24 h. Mean pH values were calculated for 30 min after gastric emptying (AGE), before the ileocecal (BIC) valve, after the ileocecal (AIC) valve, and before body exit (BBE). Intrasubject variability was determined by comparing mean values from both ingestions for an individual subject using standard deviations, 95% limits of agreement, and Bland-Altman plots.

Results: Tandem device ingestion occurred without complication. The median (full range) intrasubject standard deviations for pH were 0.02 (0.0002-0.2048) for AGE, 0.06 (0.0002-0.3445) for BIC, 0.14 (0.0018-0.3042) for AIC, and 0.08 (0.0098-0.5202) for BBE. There was a significant change in pH for AIC (mean difference: -0.45±0.31, P=0.0015) observed across all subjects. The mean coefficients of variation for transit time were 12.0±7.4% and 25.8±15.8% for small and large bowels, respectively (P=0.01).

Conclusions: This study demonstrates the safety and feasibility of tandem gut transit and pH assessments using the SmartPill device. In healthy individuals and over 24 h, the gut pH profile does not markedly fluctuate in a given region with more variation seen in the colon compared with the small bowel, which has important implications for future physiology and drug delivery studies.

No MeSH data available.