A284 CHARACTERIZING SIMULTANEOUS PRESSURE WAVES IN THE HUMAN COLON BY HIGH-RESOLUTION MANOMETRY
Bibliographic record
Abstract
High-resolution colonic manometry promises much deeper insight into human colon motor function and their control mechanisms than hitherto possible. One motor pattern in need of full understanding is the simultaneous pressure wave (SPW), an apparent instantaneous transient pressure development in the entire colon. Our aim was to provide a characterization of this motor pattern, its relationship to other motor patterns and its appearance in response to a meal, balloon distension and bisacodyl in healthy subjects. High-resolution colonic manometry (HRCM) was performed using an 84 sensor (1 cm spaced) water-perfused catheter in 16 healthy volunteers. Intraluminal pressure patterns were recorded during 90 min baseline, during balloon distension, 90 min after a meal and after luminal bisacodyl administration. Quantification was performed using software, based on Image J, developed during this study. SPWs, with amplitudes ranging from 2.4 to 75.2 mmHg (average 12 mmHg) and duration from 2 to 75s (average 11s), occurred throughout the entire colon or they developed at the termination of proximal High-Amplitude Pressure Waves (HAPWs). SPWs progressed into the anal canal followed by anal sphincter relaxation, even at very low amplitudes. SPWs did not obliterate haustral boundary contractions, likely the mechanism by which in vivo gas can escape while stool is retained. SPWs consisted of multiple high frequency, high velocity, pressure waves that resulted in apparent instantaneous pressure development. Balloon distension, a meal or luminal bisacodyl stimulation (10 mg) resulted in high amplitude SPWs associates with gas, water or balloon expulsion. SPWs and HAPWs also occurred independently and then did not influence each other. SPWs occurred in a rhythmic fashion on 26 occasions, including responses to all different stimuli; a distinct rhythmicity was identifiable at an average frequency of 1.8 ± 0.8 cpm, ranging from 0.3 to 4.4 cpm; 13 of the clusters were observed in response to the meal where the average frequency was 2.1 ± 0.9 cpm. The SPWs need to be incorporated into colonic function assessment by HRCM alongside HAPWs. It is the dominant motor pattern that allows gas expulsion and internal anal sphincter relaxation. Low- and high-amplitude SPWs are observed during baseline and are evoked by a meal, balloon distension or luminal bisacodyl. The rhythmicity of SPWs suggests the involvement of the ICC network at the submucosal border of the colon. The associated gas/liquid/balloon expulsion and anal sphincter relaxation provide potential diagnostic value. Their association with HAPWs suggest involvement in the defecation reflex. High resolution allows accurate quantification and 3-dimensional representation. High-Resolution Colonic Manometry. A proximal pressure wave, an SPW, throughout the entire colon, IAS relaxation, and a brief EAS contraction CIHRHamilton Health Sciences Organization and Canadian Foundation for Innovation John Evans Leadership Fund
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".