Air Distension Research Articles

Bowel wall visualisation at CT colonography

To evaluate the quality of bowel wall visualisation at CT colonography and the impact of examination in the supine and prone positions. After bowel preparation, 111 patients underwent CT colonography. Air distension, degree of fluid redistribution with change in body position (supine and prone), influence of residual stool on bowel wall assessability, and quality of overall colon visualisation were evaluated using scales. Thirty of 110 patients (27%) had complete overall visualisation of the colon wall and 52 (47%) had subtotal visualisation of a limited part of the colon. The entire colon was more often air-filled in the prone position (46%) than in the supine position (18%). Joint review of supine and prone data showed that for all colon segments, except the sigmoid (86%), > or =95% of the patients had complete air filling. All patients had residual fluid. In 75% to 99%, depending on segment, fluid did not interfere with the bowel wall visualisation in the combined evaluation of supine and prone data sets. Thirty-one patients had residual stool with potential negative influence on polyp detection. The colon wall was completely, or almost completely, visualised in 75% of the patients, and examination in the supine and prone positions was necessary for complete visualisation.

Mechanisms of reflexes induced by esophageal distension

We investigated the mechanisms of esophageal distension-induced reflexes in decerebrate cats. Slow air esophageal distension activated esophago-upper esophageal sphincter (UES) contractile reflex (EUCR) and secondary peristalsis (2P). Rapid air distension activated esophago-UES relaxation reflex (EURR), esophago-glottal closure reflex (EGCR), esophago-hyoid distraction reflex (EHDR), and esophago-esophagus contraction reflex (EECR). Longitudinal esophageal stretch did not activate these reflexes. Magnitude and timing of EUCR were related to 2P but not injected air volume. Cervical esophagus transection did not affect the threshold of any reflex. Bolus diversion prevented swallow-related esophageal peristalsis. Lidocaine or capsaicin esophageal perfusion, esophageal mucosal layer removal, or intravenous baclofen blocked or inhibited EURR, EGCR, EHDR, and EECR but not EUCR or 2P. Thoracic vagotomy blocked all reflexes. These six reflexes can be activated by esophageal distension, and they occur in two sets depending on inflation rate rather than volume. EUCR was independent of 2P, but 2P activated EUCR; therefore, EUCR may help prevent reflux during peristalsis. All esophageal peristalsis may be secondary to esophageal stimulation in the cat. EURR, EHDR, EGCR, and EECR may contribute to belching and are probably mediated by capsaicin-sensitive, rapidly adapting mucosal mechanoreceptors. GABA-B receptors also inhibit these reflexes. EUCR and 2P are probably mediated by slowly adapting muscular mechanoreceptors. All six reflexes are mediated by vagal afferent fibers.

Provocation of transient lower esophageal sphincter relaxations by gastric distension with air.

Transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism permitting not only gastroesophageal reflux but also venting of air from the stomach. Triggering of TLESRs is provoked by gastric distension. Antireflux surgery is associated with impaired ability to belch. It is not known whether a reduced capacity to belch results from postoperative reduction in TLESRs. We studied the occurrence of TLESRs, common cavities (indicator for gas gastroesophageal reflux), and belching after standardized acute gastric distension by air insufflation (750 ml). Control subjects (n = 10), patients with gastroesophageal reflux disease (GERD) (n = 22), and patients after fundoplication (n = 24) were studied. LES and esophageal motilities were recorded with perfusion manometry. Gastric distension with air significantly (p < 0.05) increased TLESR frequency in controls (1.6+/-0.3 to 3.5+/-1.0 per 20 min), GERD patients (1.2+/-0.3 to 3.1+/-0.5 per 20 min), and patients after fundoplication (0.5+/-0.1 to 1.8+/-0.6 per 20 min). Postfundoplication the number of TLESRs was significantly reduced (p < 0.05) both under fasting conditions and after air insufflation. The number of common cavities and belches after gastric air distension also was significantly reduced (p < 0.05) after fundoplication: 2.3+/-0.6 versus 4.7+/-0.4 in controls and 4.1+/-0.4 in GERD patients. About half of the common cavities occurred during TLESRs, and half during other mechanisms. An impaired ability to belch in daily life correlated with an impaired belching response during the test. An impaired ability to belch occurred only in patients with complete fundoplication and not in patients with partial fundoplication and was associated with a reduced number of common cavities after gastric air insufflation. Short-lasting gastric air distension 1) provokes TLESRs but does not differentiate GERD patients from controls, 2) reveals impaired belching capacity in patients after complete fundoplication, and 3) shows that common cavities do not exclusively occur during TLESRs.

Provocation of transient lower esophageal sphincter relaxations by gastric distension with air

OBJECTIVES: Transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism permitting not only gastroesophageal reflux but also venting of air from the stomach. Triggering of TLESRs is provoked by gastric distension. Antireflux surgery is associated with impaired ability to belch. It is not known whether a reduced capacity to belch results from postoperative reduction in TLESRs. METHODS: We studied the occurrence of TLESRs, common cavities (indicator for gas gastroesophageal reflux), and belching after standardized acute gastric distension by air insufflation (750 ml). Control subjects (n = 10), patients with gastroesophageal reflux disease (GERD) (n = 22), and patients after fundoplication (n = 24) were studied. LES and esophageal motilities were recorded with perfusion manometry. RESULTS: Gastric distension with air significantly ( p < 0.05) increased TLESR frequency in controls (1.6 ± 0.3 to 3.5 ± 1.0 per 20 min), GERD patients (1.2 ± 0.3 to 3.1 ± 0.5 per 20 min), and patients after fundoplication (0.5 ± 0.1 to 1.8 ± 0.6 per 20 min). Postfundoplication the number of TLESRs was significantly reduced ( p < 0.05) both under fasting conditions and after air insufflation. The number of common cavities and belches after gastric air distension also was significantly reduced ( p < 0.05) after fundoplication: 2.3 ± 0.6 versus 4.7 ± 0.4 in controls and 4.1 ± 0.4 in GERD patients. About half of the common cavities occurred during TLESRs, and half during other mechanisms. An impaired ability to belch in daily life correlated with an impaired belching response during the test. An impaired ability to belch occurred only in patients with complete fundoplication and not in patients with partial fundoplication and was associated with a reduced number of common cavities after gastric air insufflation. CONCLUSIONS: Short-lasting gastric air distension 1) provokes TLESRs but does not differentiate GERD patients from controls, 2) reveals impaired belching capacity in patients after complete fundoplication, and 3) shows that common cavities do not exclusively occur during TLESRs.

Disruption of primary and secondary esophageal peristalsis by afferent stimulation.

Recent studies have shown that afferent signals originating from the pharynx inhibit progression of primary esophageal peristalsis. Our aim was to further elucidate the effect of esophageal and pharyngeal afferent stimulation on primary and secondary esophageal peristalsis. We studied the effect of esophageal air distension and pharyngeal water stimulation on progression of primary and secondary peristalsis in nine healthy volunteers aged 27 +/- 2 yr (4 men, 5 women). At a threshold volume, rapid injection of water into the pharynx, directed posteriorly, resulted in complete halt of the progressing secondary and primary esophageal peristalses in both the proximal and distal esophagus. The threshold volume of injected water for inducing inhibition was similar for secondary (0.6 +/- 0.2 ml) and primary (0.5 +/- 0.1 ml) esophageal peristalsis. Progression of primary peristalsis induced by a dry swallow and secondary peristalsis induced by intraesophageal air distension were completely inhibited by intraesophageal injection of 15 +/- 2 ml of air in 70% and 75% of the trials, respectively. We conclude that afferent signals induced by esophageal air distension and pharyngeal water stimulation inhibit propagation of both primary and secondary esophageal peristalsis, suggesting a shared neural control mechanism for these types of peristalsis.

Pressure at the gastroesophageal junction increases in man during gastric air distension

Pressure at the gastroesophageal junction increases in man during gastric air distension

3454 Efficacy of radiofrequency energy delivery to the lower esophageal sphincter in the treatment of gerd.

Background: The delivery of radiofrequency energy (RFe) to the lower esophageal sphincter (LES) has been shown to augment the antireflux barrier in a porcine model. We sought to examine its effects in humans with GERD. Methods: Patients with chronic heartburn requiring maintenance PPI or high-dose H2RA therapy but without a hiatal hernia, severe esophagitis or complication of GERD were recruited. The following outcomes were measured at baseline and 3 months after RFe treatment: a)GERD symptoms, utilizing a validated GERD-Activity Index, b)use of antireflux medications, c)esophageal motility, including the frequency of transient LES relaxations (TLESRs) before and after stimulation with gastric air insufflation, d)ambulatory dual-channel esophageal pH testing, e)quality of life, and f)overall patient satisfaction. Results: Thus far, ten patients have completed the 3-month period of assessment. All underwent successful outpatient RFe treatment without serious adverse event. A single patient experienced some minor bleeding during the procedure. One patient failed treatment and resumed PPI therapy after 1 month. The other 9 remain off their previous antireflux medications. A dramatic improvement in symptom scores (113.4 vs. 82.4; p=0.023) and antacid use (14.5/week vs. 2.3/week; p=0.008) was noted. Improvements were also demonstrated in quality of life and overall patient satisfaction after treatment. No significant change in any esophageal motility parameter was seen; although, a trend was noted toward a reduction in the number of TLESRs induced by gastric air distension (5.3/hr vs. 3.3/hr; p=0.086). There were no detrimental effects on peristalsis or LES residual pressure. Finally, while a decrease in all pH parameters, in both the upper and lower esophagus, was seen, none reached statistical significance. Conclusions: Radiofrequency energy delivery to the region of the lower esophageal sphincter is a promising new modality in the management of GERD. It may achieve its effect by reducing stimulated TLESRs.

Pressure at the gastroesophageal junction increases in man during gastric air distension

Pressure at the gastroesophageal junction increases in man during gastric air distension

Acute Transient Sialadenopathy Associated with Laryngeal Mask Airway

Acute Transient Sialadenopathy Associated with Laryngeal Mask Airway

Biliary stent placement via percutaneous non surgical cholecystostomy

A 57-year-old man presented with a 2-month history of abdominal pain, jaundice and weight loss of 10kg. There was no relevant past medical history. Abdominal CT showed an enlarged pancreas and right adrenal gland, as well as ascites. Exploratory laparotomy revealed tumour extending through the pancreas and involving the duodenum, with seedling involvement of the gallbladder and porta hepatis. An antecolic gastrojejunostomy was performed for gastric decompression. Histopathology demonstrated poorly differentiated adenocarcinoma with prominent vascular invasion. He became progressively more jaundiced and was referred to our institution. Endoscopic retrograde cholangiopancreatography (ERCP) was unsuccessful because tumour involvement of the duodenum prevented air distension. Cannulation of the duodenal papilla and subsequent stenting was not possible. PTC revealed a narrow stricture in the lower CBD (Fig. la.). The intrahepatic ducts were not dilated and attempts to introduce a guidewire were unsuccessful. Using local anaesthetic and premedication with intravenous pethidine, the hepatic surface of the GB was catheterized using an 18 G catheter needle (Cook Denmark) and a right-sided approach in the mid-axillary line. Over a guide wire, a 5 French pigtail Thistle catheter (Cook Denmark) was inserted, coiled in the GB lumen (Fig. lb) and left in situ. The fundus of the GB was then punctured with a second 18 G catheter needle using a subhepatic approach. A guide wire was inserted and coiled in the GB lumen. A 9 French track was made to the GB fundus using concentric Teflon dilators. Using a fine 8 French Burhenne steerable catheter, a Terumo guide wire was inserted through the cystic duct and CBD and into the duodenum (Fig. lc). A straight 5 French catheter was inserted over the wire into the duodenum. The Terumo wire was replaced by an Amplatz superstiff guidewire. A 10 French Teflon pigtail stent was placed over the wire across the obstruction into the duodenum, and positioned using a pusher, so that it lay outside the cystic duct in the CBD proximally, and in the duodenum distally (Fig. ld). The 5 French GB catheter was removed 24 h later, after emptying the gallbladder of bile and residual contrast. The patient survived four months without recurrence of jaundice.

Effect of aging on the secondary esophageal peristalsis: presbyesophagus revisited

In this study we determined the effect of aging on the capability of the human esophagus to generate secondary peristalsis. We studied nine healthy young (35 +/- 2 yr, 25-45 yr) and nine healthy elderly (74 +/- 3 yr, 70-83 yr) volunteers. We stimulated secondary peristalsis by intraesophageal air injection and balloon distension. All young volunteers exhibited secondary esophageal peristalsis. In four elderly volunteers, secondary peristalsis could not be elicited with injection of any of the tested air volumes. Frequency of stimulation of secondary peristalsis and lower esophageal sphincter (LES) relaxation in response to intraesophageal air distension in the elderly was significantly lower than that in the young (P < 0.01). Stimulation of secondary peristalsis by balloon distension was less consistent compared with the air injection. In conclusion, 1) in the elderly, compared with the young, secondary esophageal peristalsis is either absent or is evoked less frequently after esophageal distension, and complete LES relaxation in response to esophageal air distension is less frequent, and 2) in both young and elderly, secondary esophageal peristalsis is induced more frequently after generalized esophageal distension by air than its segmental distension by a balloon.

Forced subarachnoid air in transsphenoidal excision of pituitary tumors (pumping technique)

Inversion and prolapse into the sella of the superior capsule and the diaphragma sellae is the only condition that warrants, at least macroscopically, radical removal of tumors with suprasellar extension operated on via the transsphenoidal route. If this does not occur spontaneously, air can be introduced into the subarachnoid space through a lumbar spinal catheter to produce forced dissection of the suprasellar cisterns and collapse of the tumor capsule ("pumping technique"). This method permits complete removal of the neoplastic tissue. In a series of 124 transsphenoidal operations for tumors with suprasellar extension, spontaneous descent of the capsule occurred in only 26 cases. Forced dissection using air distension of the cisterns was carried out in 88 cases, with complete success in 56 cases, partial success in 20, and no effect in 12. There were no complications or unwanted side effects in any patient.

Percutaneous gastrostomy and gastroenterostomy: 2. Clinical experience.

This report describes the authors' initial experience with percutaneous gastrostomy (PG) and gastroenterostomy (PGE) in 40 patients. Indications for PG and PGE included alimentation (35 patients) and small bowel decompression (five). Seldinger technique with air distension of the stomach via a nasogastric tube (20 patients) is a simple method to insert small (7-9 French) and firm catheters; tube exchanges for larger and softer catheters often are necessary by this method (23 procedures in 17 patients). Coaxial trocar technique (19 patients) permits initial insertion of softer and often larger catheters (9-14 French feeding tubes), which are less likely to clog or require exchange; the intragastric balloon support method facilitates trocar insertion. Now preferred is a system that uses 18-gauge needle puncture and allows coaxial insertion of a final soft feeding tube at the initial procedure. Small bowel catheter positioning (PGE) (31 patients) was more common than gastrostomy alone (8 patients); "downhill puncture" toward the gastric antrum assists direct guide-wire cannulation of the duodenum via the gastric puncture (12 patients). Five complications occurred; two were major and included catheter dislodgement in one patient. Another patient, who had a pharyngeal tumor, suffered profound respiratory difficulty from premedication and nasogastric tube malposition; patients with head and neck tumors present particular problems with nasogastric tube passage and airway monitoring. Inability to pass a nasogastric tube does not preclude PG and PGE, as direct puncture of the stomach is feasible.

Impaired gastric accommodation to distension and rapid gastric emptying in patients with Chagas' disease.

In order to evaluate the contribution of the myenteric plexuses to the control of gastric accommodation to distension and to the rate of gastric emptying of a saline solution in man, we have evaluated these functions in patients with Chagas' disease, which is known to be associated with extensive lesions of the myenteric plexuses. Intragastric pressure was significantly higher (P < 0.05) in Chagas patients (N = 15) than in normal controls (N = 15) for air distension volumes of 100-700 ml. In the range 300-700 ml, the difference between the groups was approximately twofold (P < 0.001). The gastric emptying rate of 500 ml 154 mM NaCl in a second group of Chagas' disease patients (N = 13) was significantly faster than that of the control group (N = 17) at 5 min (P < 0.005) and at 15 min (P < 0.005) after the test meal, but at 25 min the volumes remaining in the stomach were not statistically significant for the two groups (P > 0.10). The impairment of gastric accommodation to distension and consequent rapid gastric emptying demonstrated for chagasic patients emphasizes the role of the myenteric plexuses in gastric reservoir function in man and complements previous evidence obtained in animal studies.

Computed Tomography of the Pelvis

AbstractThe computed tomography scan has revealed the location and size of abnormal pelvic masses as an adjunct to other diagnostic studies. We have extended its usefulness by air distension of the bladder, which accommodates to adjacent structures and, thereby, highlights abnormalities in its own wall and in other organs. The patients are prepared according to a simple routine. As we attempt further economy and efficiency the cost of each study becomes justified by the information gained.

Drainage of the rectum: a simple maneuver to improve the accuracy of colon examinations.

In double contrast enemas, the rectum and distal sigmoid can easily be examined with a high degree of accuracy. This requires adequate drainage and good air distension of this segment of the colon. Methods are outlined by which this can easily be accomplished.