High amplitude propagated contractions

While most colonic motor activity is segmental and non‐propulsive, colonic high amplitude propagated contractions (HAPC) can transfer colonic contents over long distances and often precede defecation. High amplitude propagated contractions occur spontaneously, in response to pharmacological agents or colonic distention. A subset of patients with slow transit constipation have fewer HAPC. In this issue of Neurogastroenterology and Motility, Rodriguez et al. report that anal relaxation during spontaneous and bisacodyl‐induced HAPC exceeds anal relaxation during rectal distention in constipated children undergoing colonic manometry. Moreover, and consistent with a neural mechanism, anal relaxation often precedes arrival of HAPC in the left colon. High amplitude propagated contractions are also used to evaluate the motor response to a meal and pharmacological stimuli (e.g., bisacodyl, neostigmine) and to identify colonic inertia during colonic motility testing in chronic constipation. This editorial comprehensively reviews the characteristics, physiology and pharmacology of HAPC, their assessment by manometry, and relevance to constipation and diarrhea.     

Prolonged stationary colonic motility recording in seven patients with severe constipation secondary to antidepressants

The aim of this study was to determine whether the colonic motor profile of seven patients with constipation secondary to antidepressants differed from the motility of seven patients with idiopathic constipation and seven healthy volunteers. All constipated patients had very severe constipation. Colonic manometric recordings were performed for 24 h. The number of high amplitude propagating contractions (HAPC) was lower in the two groups of constipated patients than in controls. No HAPC were observed in 5/7 patients with constipation secondary to antidepressants and in 1/7 patients with idiopathic constipation. The overall area under the curve (AUC) in the left colon was lower in the two constipated patient groups than in controls. AUC increased after a 1000-kcal standard meal given at noon in controls but not in the two groups of constipated patients. In conclusion, in patients with constipation secondary to antidepressants, the overall AUC was as poor as in patients with idiopathic constipation, and no colonic response to eating was observed. Moreover, the number of HAPC was more markedly decreased in patients with constipation secondary to antidepressants than in patients with idiopathic constipation.     

Altered periodic rectal motor activity: a mechanism for slow transit constipation

The pathophysiology of slow transit constipation is poorly understood. Both decreased and increased distal colonic motility have been reported. In healthy humans, a 3 cycles per minute (cpm), periodic rectal motor activity (PRMA) has been described. Our aim was to investigate the characteristics of PRMA and to assess its role in the pathogenesis of constipation. A six-sensor solid-state probe was placed with the tip sensor in the mid-transverse colon, without sedation, and prolonged colonic motility was recorded in nine patients with slow transit constipation (1M, 8F) and in 11 healthy subjects (3M, 8F). Subjects were free to ambulate. We examined the frequency, nocturnal vs. diurnal variation, and characteristics of PRMA, and its relationship to proximal colonic motility. All subjects showed PRMA. The rhythm was similar (2.5-4 cpm) in both groups. However, constipated patients exhibited a greater (P < 0.001) number of PRMA cycles than controls. The duration of each cycle and amplitude of pressure waves during PRMA were also greater (P < 0.05) at night in patients compared with controls. In patients, 40% of PRMA cycles were associated with a proximal colonic motor event compared with 81% in controls (P < 0.02). The area under the curve of all colonic pressure waves and incidence of specialized propagating pressure waves was lower (P < 0.05) in patients during daytime. When compared with controls, constipated patients exhibited reduced daytime colonic pressure waves and a higher frequency of PRMA. Most of the PRMA was unrelated to proximal colonic activity in constipated patients in contrast with findings in control patients. In addition to decreased colonic motility, this excessive and unco-ordinated phasic rectal activity may further impede stool transport and contribute to the pathogenesis of slow transit constipation.     

Pilot study of pyridostigmine in constipated patients with autonomic neuropathy

BACKGROUND: The effects of cholinesterase inhibitors, which increase colonic motility in health, on chronic constipation are unknown. Our aims were to evaluate the efficacy of cholinesterase inhibitors for dysautonomia and chronic constipation and to assess whether acute effects could predict the long term response. METHODS: In this single-blind study, 10 patients with autonomic neuropathy and constipation were treated with placebo (2 weeks), followed by an escalating dose of pyridostigmine to the maximum tolerated dose (i.e., 180-540 mg daily) for 6 weeks. Symptoms and gastrointestinal transit were assessed at 2 and 8 weeks. The acute effects of neostigmine on colonic transit and motility were also assessed. RESULTS: At baseline, 4, 6, and 3 patients had delayed gastric, small intestinal, and colonic transit respectively. Pyridostigmine was well tolerated in most patients, improved symptoms in 4 patients, and accelerated the geometric center for colonic transit at 24 h by > or =0.7 unit in 3 patients. The effects of i.v. neostigmine on colonic transit and compliance predicted (P < 0.05) the effects of pyridostigmine on colonic transit. CONCLUSIONS: Pyridostigmine improves colonic transit and symptoms in some patients with autonomic neuropathy and constipation. The motor response to neostigmine predicted the response to oral pyridostigmine.     

Distention of the colon is associated with initiation of propagated contractions in children

Abstract  The presence of high-amplitude propagating contractions (HAPCs) has been identified as a marker of colonic neuromuscular integrity. The physiologic mechanisms of HAPCs initiation have yet to be determined. Distention secondary to colonic filling has been hypothesized as physiologic initiator. The aim of this study was to study the effect of intraluminal balloon distention in the colon of children with defecatory disorders. Colonic manometry was performed with a polyethylene balloon situated at the proximal end of the catheter, which was placed in the most proximal colonic segment reached during colonoscopy. A stepwise pressure controlled distention of the balloon was performed using barostat computer (10–50 mmHg). Propagated contractions were defined as those that migrated over at least three recording sites. They were divided into HAPCs, amplitude >60 mmHg and low-amplitude propagating contractions (LAPCs), amplitude <60 mmHg. Children with spontaneous HAPCs or HAPCs after bisacodyl provocation were considered to have normal motility. Twenty children completed the study. Among the 14 children with normal colonic motility, balloon distention elicited HAPCs in four and LAPCs in 10 children. No HAPC were elicited in six children with abnormal motility and LAPCs were seen in four of them. The balloon-induced propagated contractions had similar characteristics as those occurring spontaneously and after bisacodyl provocation but the pressure needed to elicit them and their amplitude was inconsistent. These findings suggest that intraluminal distention can trigger propagated contractions in children. This mechanism of action for induction of propagated contractions is not as consistent as the motor response found in response to bisacodyl administration.     

Pancolonic spatiotemporal mapping reveals regional deficiencies in,and disorganization of colonic propagating pressure waves in severe constipation

Background The morphology, motor responses and spatiotemporal organization among colonic propagating sequences (PS) have never been defined throughout the entire colon of patients with slow transit constipation (STC). Utilizing the technique of spatiotemporal mapping, we aimed to demonstrate ‘manometric signatures’ that may serve as biomarkers of the disorder. Methods In 14 female patients with scintigraphically confirmed STC, and eight healthy female controls, a silicone catheter with 16 recording sites spanning the colon at 7.5 cm intervals was positioned colonoscopically with the tip clipped to the cecum. Intraluminal pressures were recorded for 24 h. Key Results Pan‐colonic, 24 h, spatiotemporal mapping identified for the first time in STC patients: a marked paucity of propagating pressure waves in the mid‐colon (P = 0.01), as a consequence of a significant (P < 0.0001) decrease in extent of propagation of PS originating in the proximal colon; an increase in frequency of retrograde PS in the proximal colon; a significant reduction in the spatiotemporal organization among PS (P < 0.001); absence of the normal nocturnal suppression of PS. Conclusions & Inferences Pan‐colonic, 24 h, spatiotemporal pressure mapping readily identifies characteristic disorganization among consecutive PS, regions of diminished activity and absent or deficient fundamental motor patterns and responses to physiological stimuli. These features are all likely to be important in the pathophysiology of slow transit constipation.     

Classification of normal and abnormal colonic motility based on cross‐correlations of pancolonic manometry data

Background Manual analysis of data acquired from manometric studies of colonic motility is laborious, subject to laboratory bias and not specific enough to differentiate all patients from control subjects. Utilizing a cross‐correlation technique, we have developed an automated analysis technique that can reliably differentiate the motor patterns of patients with slow transit constipation (STC) from those recorded in healthy controls. Methods Pancolonic manometric data were recorded from 17 patients with STC and 14 healthy controls. The automated analysis involved calculation of an indicator value derived from cross‐correlations calculated between adjacent recording sites in a manometric trace. The automated technique was conducted on blinded real data sets (observed) and then to determine the likelihood of positive indicator values occurring by chance, the channel number within each individual data set were randomized (expected) and reanalyzed. Key Results In controls, the observed indicator value (3.2 ± 1.4) was significantly greater than that predicted by chance (0.8 ± 1.5; P < 0.0001). In patients, the observed indicator value (?2.7 ± 1.8) did not differ from that predicted by chance (?3.5 ± 1.6; P = 0.1). The indicator value for controls differed significantly from that of patients (P < 0.0001), with all individual patients falling outside of the range of indicator values for controls. Conclusions & Inferences Automated analysis of colonic manometry data using cross‐correlation separated all patients from controls. This automated technique indicates that the contractile motor patterns in STC patients differ from those recorded in healthy controls. The analytical technique may represent a means for defining subtypes of constipation.     

Anatomical registration and three‐dimensional visualization of low and high‐resolution pan‐colonic manometry recordings

Background Colonic propagating sequences (PS) are important for the movement of colonic content and defecation, and aberrant PS patterning has been associated with slow transit constipation. However, because these motor patterns are typically recorded over long periods (24 h +), the visualization of PS spatiotemporal patterning is difficult. Here, we develop a novel method for displaying pan‐colonic motility patterns. Methods A 3D mesh representing the geometry of the human colon was created as follows: (i) Human colon images from the Visible Human Dataset were digitized to create a 3D data cloud, and (ii) A surface mesh was fitted to the cloud using a least‐squares minimization technique. Colonic manometry catheters were placed in the ascending colon of healthy controls and patients with slow transit constipation (STC), with the aid of a colonoscope. The colonic manometry data were interpolated and mapped to the model according to the following anatomical landmarks: cecum, hepatic flexure, splenic flexure, sigmoid‐descending junction, and anus. Key Results These 3D images clearly and intuitively communicate characteristics of normal and abnormal colonic motility. Specifically we have shown the reduced amplitude of the antegrade propagating pressure waves (PPW) throughout the colon and reduced frequency of PPWs at the mid‐colon in patients with STC. Conclusions and Inferences A novel method for the 3D visualization of PS is presented, providing an intuitive method for representing a large volume of physiological data. These techniques can be used to display frequency, amplitude or velocity data, and will help to convey regions of abnormally in patient populations.     

Manometric techniques for the evaluation of colonic motor activity: current status

Colonic motility disorders are common conditions. However, our understanding of normal, and, consequently, pathological motor function of the colon remains limited, mainly due to the relative inaccessibility of this organ for study. Investigation of colonic motility may encompass one or more of the four separate components (myoelectric activity, phasic and tonic contractile activity and movement of intraluminal content) using electrophysiological, manometric or transit studies. Although transit studies provide the best 'functional' appreciation of colonic motor activity, and are the only techniques used in contemporary clinical practice, manometric methods are becoming increasingly popular, as they allow a direct study of colonic contractile activity over prolonged periods. To date, the majority of studies have been limited to the pelvic colon by a retrograde (per rectal) approach; however, recent technological advances have facilitated 'pan-colonic' investigation. This review concentrates on manometry of the human colon proximal to the sigmoid, and includes evaluation of both phasic and tonic motor activity, by utilization of perfused-tube and solid-state manometric catheters, and also the electronic barostat. Methodological techniques, experimental protocols and the analysis and interpretation of recorded data are critically explored, and a contemporary classification of colonic contractile activities is presented.     

High‐resolution colonic manometry accurately predicts colonic neuromuscular pathological phenotype in pediatric slow transit constipation

Background Severe pediatric slow transit constipation (STC) is commonly due to intrinsic colonic neuromuscular disease. We sought to correlate neuromuscular histological phenotypes in pediatric STC with colonic manometric phenotypes using high‐resolution manometry (HRM). We tested the hypothesis that failure of motor quiescence (FQ) between bisacodyl‐induced high amplitude propagating sequences (HAPSs) might predict neuromuscular pathology. Methods Eighteen children (10 males, median age: 7.5 years) with refractory STC underwent stationary colonic HRM before segmental colonic resection. Six age‐matched constipated children with normal colonic transit served as controls. Colonic resection specimens underwent histopathological analysis. Conventional manometric parameters and area under the curve (AUC) during a 1‐min period following bisacodyl‐induced HAPSs [PBAUC₁], as measure of FQ, were calculated. Key Results Numbers of postbisacodyl HAPSs in descending and sigmoid segments were lower in patients than controls (P < 0.01, respectively). Low amplitude propagating sequences (LAPSs) were common prebisacodyl in controls and rare in STC (P < 0.001), whereas postbisacodyl LAPS were more common in STC (P < 0.001). Postbisacodyl, both retrograde propagating contractions and bursts of contractions were present in STC patients only (P < 0.001 and P < 0.01). Postbisacodyl simultaneous pressurization was seen only in STC (P < 0.05 and P < 0.001, in descending and rectosigmoid segments). Histological abnormalities were present in 17/18. Fourteen were neurogenic, one neuro‐myogenic, and two myogenic. In segments with HAPS, PBAUC₁ was predictive of colonic neuropathy using a cutoff of 205 mmHg.s^‐1 (Sensitivity 100%, specificity 86%, PPV92%, NPV100%). Conclusions & Inferences PBAUC₁ is increased in multiple colonic segments in neuropathic pediatric STC and constitutes a sensitive and specific biomarker of neuropathy.     

Internal anal sphincter relaxation associated with bisacodyl‐induced colonic high amplitude propagating contractions in children with constipation: a colo‐anal reflex?

Background Describe the association of internal anal sphincter (IAS) relaxation with colonic high‐ amplitude peristaltic contractions (HAPCs). Methods Retrospective review of colon manometry tracings of children with constipation to determine the IAS relaxation characteristics associated with HAPC’s (HAPC‐IASR) events and compare them to the those seen during the performance of the anorectal manometry (ARMRAIR) events. Key Results A total of 70 HAPC‐ IASRs were observed in 15 patients, 65 after bisacodyl, two during fasting and three after a meal. In 64% of events, the IAS relaxation started when the HAPC reached left colon and in 36% as proximal as the hepatic flexure. High‐ amplitude peristaltic contraction propagation seems to be important in HAPC‐IASR characteristics; those propagating distal to sigmoid colon demonstrated larger and longer IAS relaxation as well as lower residual pressure, but equivalent resting pressure compared with HAPC’s ending proximal to sigmoid colon. Although IAS resting pressure was comparable for ARM‐RAIRs and HAPC‐IASRs, the duration and magnitude of anal relaxation was higher, and the anal residual pressure was lower in HAPC‐IASRs. Conclusions & Inferences We demonstrated that IAS relaxation in constipated children is associated with HAPCs migrating in the proximal and distal colon; in most cases, starting when peristalsis is migrating through left colon and in an important proportion while migrating proximally. We also demonstrated that HAPC‐IASRs are different from ARM‐RAIRs suggesting a neurally mediated reflex. Finally, the IAS relaxation characteristics are highly dependent on the degree of propagation of HAPCs, which could have important implications in the understanding of defecation disorders.     

Effect of bowel cleansing on colonic transit in constipation due to slow transit or evacuation disorder

Colon transit time measurement with radio-opaque markers is a method of studying the passage of luminal contents throughout the colon. Overall colonic transit time (CTT), as well as segmental transit times [right (RTT), left (LTT) and rectosigmoid (RSTT)], can be calculated. We hypothesize that CTT is influenced by faecal impaction when the rectum is emptied infrequently. The aim of this study is to investigate the effect of bowel cleansing on colonic transit time in patients with chronic constipation. In 25 women (age 41 years; range 20-65 years) with constipation according to Thompson criteria, CTT measurement was performed in an unprepared situation and repeated after cleansing with 4 L of Klean-Prepreg. Ten healthy female volunteers (age 41 years; range 27-57 years) were used as controls. In constipated patients, CTT decreased from a median 70 h (range 10-130 h) to 48 h (5-94 h) in the cleansed state (P < 0.001). A shortening of transit time was found in all three segments. In 10 patients with slow transit (ST) (CTT > 86 h), CTT decreased from 110 h (range 94-130) to 86 (38-94) (P < 0.001). Five of the 10 patients with ST before bowel cleansing had a CTT below 86 h after cleansing. In female controls, uncleansed CTT and RSTT shortened from 39 h (23 to 62) and 17 h (8-29) to 29 h (17-48) and 10 h (0-20) after bowel cleansing (P=0.058 and P=0.046). Colonic intraluminal contents have a substantial effect on colonic transit. In female controls, bowel cleansing shortened rectosigmoid transit. Women with constipation had faster transit in the cleansed state, however, the distribution of markers was not altered. Despite the effect of bowel cleansing on CTT, it seems unnecessary to prepare the bowel in clinical practice because the differentiation of patients between slow transit constipation and outlet obstruction is not changed. However, because in an infrequent defecation pattern, the influence of faecal impaction is considerable, CTT should be applied with care for critical clinical decisions in the treatment of constipation.     

Colonic transit time in patients with myelomeningocele

To evaluate colonic motility in patients with myelomeningocele, the transit time of radiopaque markers was studied in 22 patients with myelomeningocele and 22 age and sex matched controls. Mean colonic transit time was significantly longer in patients than in controls (103.2 ± 49 h versus 23.3 ± 13 h; P < 10⁻⁷). Thirteen of 22 patients with myelomeningocele were severely constipated. Six patients had constipation secondary to delayed colonic transit, particularly in the left colon, and seven had increased rectosigmoïd transit. The clinical questionnaire and particularly the frequency of bowel movements did not predict colonic transit. Among 13 patients with increased colonic transit, eight had more than five bowel movements per week and, thus, six of them did not use laxatives or enemas, despite the presence of faecal incontinence. There was no relationship between colonic transit time and the level of the spinal lesion or patient mobility in patients with myelomeningocele. Rectoanal dyssynergia was found in 14 of the 22 patients, but equally often in patients with delayed rectosigmoid transit (4/7) as in the other patients (10/15) (P = ns). Uninhibited detrusor contractions were observed more often in patients with increased colonic transit time than in others (8/12 versus 1/8, P = 0.05). In the absence of a correlation between colonic transit time, clinical symptoms, anorectal motility, level of spinal lesion, patient mobility, evaluation of colonic transit of radiopaque markers should be assessed routinely in all patients with myelomeningocele to plan the most appropriate treatment, mainly in case of unhibited detrusor contractions.     

A randomized controlled trial of a probiotic combination VSL# 3 and placebo in irritable bowel syndrome with bloating

AIM: To evaluate the effects of a combination probiotic on symptoms and colonic transit in patients with irritable bowel syndrome (IBS) and significant bloating. METHODS: Forty-eight patients with Rome II IBS were randomized in a parallel group, double-blind design to placebo or VSL# 3 twice daily (31 patients received 4 weeks and 17 patients 8 weeks of treatment). Pre- and post-treatment colonic transit measurements were performed using scintigraphy with (111)In charcoal. Symptoms were summarized as an average daily score for the entire period of treatment and separately for the first 4 weeks of treatment. Weekly satisfactory relief of abdominal bloating was assessed. RESULTS: Treatment with VSL# 3 was associated with reduced flatulence over the entire treatment period (placebo 39.5 +/- 2.6 vs VSL# 3 29.7 +/- 2.6, P = 0.011); similarly, during the first 4 weeks of treatment, flatulence scores were reduced (placebo 40.1 +/- 2.5 vs VSL# 3 30.8 +/- 2.5, P = 0.014). Proportions of responders for satisfactory relief of bloating, stool-related symptoms, abdominal pain and bloating scores were not different. Colonic transit was retarded with VSL# 3 relative to placebo (colon geometric center 2.27 +/- 0.20 vs 2.83 +/- 0.19, P = 0.05 respectively). CONCLUSION: VSL# 3 reduces flatulence scores and retards colonic transit without altering bowel function in patients with IBS and bloating.     

Manometric correlations of anorectal dysfunction and biofeedback outcome in patients with multiple sclerosis

OBJECTIVE: To evaluate clinical and manometric characteristics of multiple sclerosis (MS) patients with anorectal dysfunction (ARD) and their influence on biofeedback outcome. PATIENTS AND METHODS: Patients were clinically and manometrically studied and compared with controls. Patients were subsequently offered to initiate biofeedback manoeuvres to improve ARD. RESULTS: Fifty-two patients with ARD, 39 women, mean age 44.96 +/- 9.26 years, mean Expanded Disability Status Scale 4.13 +/- 1.72, were evaluated. Thirty-one patients had relapsing-remitting (RR), 16 secondary progressive and five primary progressive MS. ARD complaints were constipation (67.3%), double ARD (23.1%) and isolated incontinence (9.6%). The manometric study showed significant differences in patients compared with controls in maximal contraction pressures (98.1 +/- 44.2 mm Hg versus 152.05 +/- 66.9 mm Hg, P < 0.001) and anal inhibitory reflex threshold (92.9 +/- 63.4 mL versus 40.45 +/- 11.3 mL, P < 0.001). Maximal pressure was lower in progressive forms compared with RR forms (83.1 +/- 36.2 mm Hg versus 108.2 +/- 46.7 mm Hg, P < 0.05) in relation to higher disability. Patients with paradoxical contraction (PC) (35 patients, 67.3%) showed more manometric disturbances. From a total of 18 patients performing biofeedback, those reporting some improvement (six complete, two partial) had milder manometric abnormalities. CONCLUSIONS: The most frequent manometric abnormalities in our MS patients with ARD were alterations of maximal pressures, anal inhibitory reflex and PC. Biofeedback could be more useful in patients with lower disability and manometric alterations.     

Regional variation in the neurochemical coding of the myenteric plexus of the human colon and changes in patients with slow transit constipation

Abstract There are differences in the structure and function between regions of the colon. In patients with slow transit constipation the activity of all regions is markedly slowed. Counts of colonic neurones in slow transit constipation have been semiquantitative and led to varying results. We have applied new methods of quantification of markers in whole mounts of the colonic myenteric plexus to compare density of innervation between regions and between normal patients and those undergoing resection for severe constipation. Whole mounts of colonic myenteric plexus were made from specimens removed for cancer treatment (controls) and cases of severe constipation. All neurones were labelled by anti‐human neuronal protein antibodies. Neurones synthesizing acetyl choline were labelled for choline acetyltransferase (ChAT) and those for nitric oxide by antisera to nitric oxide synthase (NOS). Four populations of neurones were distinguished and quantified according to the two selective markers, ChAT and NOS. In the normal major populations were NOS alone (51% of ascending colon neurones and 44% of descending colon neurones) and ChAT alone (41% ascending colon, 48% descending colon). Nitric oxide synthase/ChAT and NOS‐/ChAT‐comprised only small populations. In all regions in severe constipation, the percentage of NOS‐only colonic myenteric neurones was raised (54% ascending colon, 49% descending colon) and ChAT only was reduced (36% ascending colon, 42% descending colon). The other populations were not changed. Accurate quantification of neuronal populations in whole mounts of human colon reveals inter‐regional differences in innervation and marked changes in innervation in cases of very severe constipation.     

Substance P and vasoactive intestinal peptide are reduced in right transverse colon in pediatric slow‐transit constipation

Background Slow‐transit constipation (STC) is recognized in children but the etiology is unknown. Abnormalities in substance P (SP), vasoactive intestinal peptide (VIP) and nitric oxide (NO) have been implicated. The density of nerve fibers in circular muscle containing these transmitters was examined in colon from children with STC and compared to other pediatric and adult samples. Methods Fluorescence immunohistochemistry using antibodies to NO synthase (NOS), VIP and SP was performed on colonic biopsies (transverse and sigmoid colon) from 33 adults with colorectal cancer, 11 children with normal colonic transit and anorectal retention (NAR) and 51 with chronic constipation and slow motility in the proximal colon (STC). The percentage area of nerve fibers in circular muscle containing each transmitter was quantified in confocal images. Key Results In colon circular muscle, the percentage area of nerve fibers containing NOS > VIP > SP (6 : 2 : 1). Pediatric groups had a higher density of nerve fibers than adults. In pediatric samples, there were no regional differences in NOS and VIP, while SP nerve fiber density was higher in sigmoid than proximal colon. STC children had lower SP and VIP nerve fiber density in the proximal colon than NAR children. Twenty‐three percent of STC children had low SP nerve fiber density. Conclusions & Inferences There are age‐related reductions in nerve fiber density in human colon circular muscle. NOS and VIP do not show regional variations, while SP nerve fiber density is higher in distal colon. 1/3 of pediatric STC patients have low SP or VIP nerve fiber density in proximal colon.     

Day‐to‐day reproducibility of prolonged ambulatory colonic manometry in healthy subjects

Background Although colonic manometry provides useful information regarding colonic physiology, considerable variability has been reported both for regional motility and manometric patterns. Whether colonic manometry is reproducible is not known. Methods Seven healthy volunteers (three men, four women, mean age = 34 years) underwent two studies of 24‐h ambulatory colonic manometry, each 2 weeks apart. Manometry was performed by placing a six‐sensor solid‐state probe, up to the hepatic flexure and anchored to colonic mucosa. Colonic motility was assessed by the number and area‐under‐curve (AUC) of pressure waves and motility patterns such as high‐amplitude propagating contractions (HAPC). Waking and meal‐induced gastrocolonic responses were also assessed. Paired t‐test was used to examine the reproducibility and intra and interindividual variability. Key Results The number of pressure waves and propagating pressure waves and HAPC, and AUC were similar between the two studies. Diurnal variation, waking and meal‐induced gastrocolonic responses were also reproducible. There was some variability in the incidence of individual colonic motor patterns. Conclusions & Inferences Colonic manometry findings were generally reproducible, particularly for the assessment of key physiologic changes, such as meal‐induced gastrocolonic, HAPC, and waking responses.     

Constipation associated with chronic spinal cord injury: the effect of pelvic parasympathetic stimulation by the Brindley stimulator.

Ten subjects with severe constipation due to complete spinal cord injury (SCI) had prolonged oro-anal transit time (p less than 0.01), diminished faecal water content (p less than 0.05) and a reduced frequency of defaecation (p less than 0.01) compared to 10 non-SCI subjects. Paraplegics with an implanted Brindley S234 anterior sacral nerve root stimulator had a significant increase in frequency of defaecation (p less than 0.01), compared to the SCI group while the faecal water content was less although not significantly so. The Brindley stimulator group also showed a more rapid colonic transit than the SCI group but this did not reach statistical significance. SCI is associated with constipation which therefore appears to be favourably influenced by the Brindley S234 anterior nerve root stimulator. The effects produced are compatible with stimulation of left colonic motility, which facilitates the emptying of the distal colon, but also suggest that part of the response restricts transit in some areas of the colon or rectum. Since the motility changes induced by the Brindley stimulator do not affect the right colon a relatively greater residence time of the faecal bolus in this part of the large bowel would enhance water absorption.     

Influence of continuous isobaric rectal distension on gastric emptying and small bowel transit in young healthy women

Patients with slow transit constipation frequently have delayed gastric emptying. In animals rectal distensions inhibit gastrointestinal motility. In healthy volunteers isovolumetric rectal distensions delay upper gut transit. The purpose of this study was to determine the effect of continuous isobaric rectal distension on gastric emptying and oro-cecal transit in young females. Using validated 13C octanoic and lactose-[13C] ureide breath tests gastric half-emptying time and oro-cecal transit time for a meal were measured in 12 volunteers. The tests were repeated in randomized order: during isobaric balloon distension and during sham distension. Isobaric rectal distension was applied using a polyethylene bag connected to a barostat. Intraballoon pressure was kept just below the threshold for the urge sensation. Mean gastric half-emptying time during rectal distension (92.3 +/-5.1 min) was significantly higher than during sham distension (78.8 +/- 4 min; P = 0.015). Mean oro-cecal transit time during rectal distension (391.3 +/-29.1 min) and sham distension (328.8 +/- 38.4 min) were not significantly different. In conclusion, these findings indicate that isobaric rectal distension inhibits gastric emptying, but not small bowel transit in young healthy women. Studies in patients with constipation are indicated.