A controlled study of the effect of midazolam on abnormal sphincter of Oddi motility

How to interpret a functional or motility test - sphincter of oddi manometry

To date, endoscopic manometry is the best method for evaluating the function of the sphincter. Sphincter of Oddi manometry (SOM) remains the gold standard to correctly diagnose the sphincter of Oddi dysfunction (SOD) and stratify therapy. Several dynamic abnormalities relating to the intensity, frequency, and propagation of sphincter contractions have been described. However, their clinical use generally has been abandoned in favor of basal sphincter pressure alone, because this measurement is stable over time, and has stronger interobserver reliablility, reproducibility on repeating testing, and is associated with the responsiveness to therapy. A significant elevated risk of pancreatitis was attributed to the technique. The risk of pancreatitits associated with manometric evaluation of the pancreatic sphincter is markedly reduced when manometry is performed with continous aspiration from the pancreatic duct via one of the 3 catheter lumens. This section reviews indications, conscious sedative drugs, techniques, and the appropriate interpretations of SOM.

Prospective evaluation of adjunctive ketamine on sphincter of Oddi motility in humans

BACKGROUND AND AIM

Performance of sphincter of Oddi manometry (SOM) at endoscopic retrograde cholangio-pancreatogram (ERCP) is technically demanding and requires that the patient be well sedated. Droperidol is used as an adjunctive agent in patients who are difficult to sedate. Concerns regarding the safety profile of droperidol and its effects on sphincter of Oddi motility has resulted in the search for other potent sedative agents that do not influence SOM readings. Ketamine, a dissociative anesthetic, is increasingly being used as an adjunctive agent for conscious sedation. This study evaluates the effect of ketamine on sphincter of Oddi motility when used as an adjunctive sedative agent during ERCP.

PATIENTS AND METHODS

This is a prospective study of 30 consecutive patients undergoing SOM who were difficult to sedate and required adjunctive ketamine. Manometry was initially performed with intravenous administration of diazepam plus meperidine or a combination of diazepam plus meperidine and midazolam. After the initial two pull-throughs, 20 mg of ketamine was administered intravenously and the measurements were repeated 5 min later.

RESULTS

The basal pressures of the biliary sphincter and of the pancreatic sphincter were not significantly altered by ketamine. By using a definition for sphincter of Oddi dysfunction of a basal pressure >or=40 mmHg, concordance (normal vs abnormal) between the basal sphincter pressure before and after ketamine was seen in 28 patients (93%). Ketamine also did not lead to a difference in phasic wave amplitude, duration, or frequency. No complication was associated with ketamine use.

CONCLUSIONS

Ketamine at 20 mg did not significantly affect SOM parameters. Further studies are required to confirm our preliminary findings before ketamine can be added to the armamentarium of agents used for performance of sphincter of Oddi manometry.

Prevalence of sphincter of Oddi dysfunction in patients referred to endoscopic retrograde cholangiopancreatography

BACKGROUND: Sphincter of Oddi manometry is the gold-standard method for sphincter of Oddi dysfunction. The prevalence of sphincter of Oddi dysfunction among patients referred to endoscopic retrograde cholangiopancreatography is largely unknown. AIM: To evaluate prospectively the prevalence of biliary sphincter of Oddi dysfunction (B-SOD) among Brazilian patients referred to endoscopic retrograde cholangiopancreatography and to study the safety of sphincter of Oddi manometry in this setting. METHODS: Biliary sphincter of Oddi manometry was intended in 110 patients referred to endoscopic retrograde cholangiopancreatography. The number of attempts to obtain deep cannulation with the manometry catheter was recorded and patients were divided into two groups: up to 5 (easy cannulation) and >5 attempts (difficult cannulation). RESULTS: Sphincter of Oddi manometry was successful in 71/110 patients (64.5%). Sphincter of Oddi dysfunction was found in 18/71 patients (25%). Endoscopic retrograde cholangiopancreatography findings were: normal in 16, biliary stones in 39, malignant biliary strictures in 9 and benign biliary strictures in 7. There was no statistical difference in sphincter of Oddi dysfunction prevalence regarding disease, gender or difficulty of cannulation. Only 2/71 patients developed post-procedure mild pancreatitis. CONCLUSIONS: We have found a high prevalence of sphincter of Oddi dysfunction in patients referred to endoscopic retrograde cholangiopancreatography. Gender, nature of disease or difficulty of cannulation did not influence the prevalence of sphincter of Oddi dysfunction among these patients. Sphincter of Oddi manometry is a safe procedure for the evaluation of sphincter of Oddi dysfunction in patients referred to endoscopic retrograde cholangiopancreatography.

Sphincter of Oddi dysfunction: managing the patient with chronic biliary pain

Sphincter of Oddi dysfunction (SOD) is a syndrome of chronic biliary pain or recurrent pancreatitis due to functional obstruction of pancreaticobiliary flow at the level of the sphincter of Oddi. The Milwaukee classification stratifies patients according to their clinical picture based on elevated liver enzymes, dilated common bile duct and presence of abdominal pain. Type I patients have pain as well as abnormal liver enzymes and a dilated common bile duct. Type II SOD consists of pain and only one objective finding, and Type III consists of biliary pain only. This classification is useful to guide diagnosis and management of sphincter of Oddi dysfunction. The current gold standard for diagnosis is manometry to detect elevated sphincter pressure, which correlates with outcome to sphincterotomy. However, manometry is not widely available and is an invasive procedure with a risk of pancreatitis. Non-invasive testing methods, including fatty meal ultrasonography and scintigraphy, have shown limited correlation with manometric findings but may be useful in predicting outcome to sphincterotomy. Endoscopic injection of botulinum toxin appears to predict subsequent outcome to sphincterotomy, and could be useful in selection of patients for therapy, especially in the setting where manometry is unavailable.

In vitro effects of intravenous anesthetics on the sphincter of Oddi strips of sheep

BACKGROUND

Intravenous anesthetics are often used for conscious sedation in endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincter of Oddi (SO) manometry. This study was designed to investigate the direct effects of some intravenous anesthetics on SO in sheep.

METHODS

In sheep SO rings, changes in isometric tension in response to cumulative concentrations of intravenous anesthetics were determined, and values for Emax (mean maximal inhibition) and pD2 (i.e. the negative logarithm of the concentration for the half-maximal response, EC50) were compared.

RESULTS

Meperidine (10(-7) to 3 x 10(-5) M), fentanyl (10(-7) to 3 x 10(-5) M), midazolam (10(-7) to 3 x 10(-5) M) and propofol (10(-7) to 3 x 10(-4) M) induced concentration-dependent relaxations on SO precontracted with carbachol (10(-6) M). Emax and pD2 values following meperidine, fentanyl and midazolam administration were significantly greater than after propofol (p < 0.05). There were no significant differences in Emax and pD2 values for meperidine, fentanyl and midazolam.

CONCLUSION

These results suggest that meperidine, fentanyl and midazolam are equipotent relaxants in the sheep SO in vitro. The relaxatory effect of propofol was 10 times less potent compared to the above agents, and it can be beneficial during SO manometry in controlled clinical human studies.

Prospective evaluation of droperidol on sphincter of Oddi motility

BACKGROUND

Droperidol increasingly is used as an effective adjunct for conscious sedation during endoscopic procedures. Given the concern for the effects of narcotics and benzodiazepines on sphincter of Oddi motility, and the potential difficulty in sedating patients undergoing sphincter of Oddi manometry, droperidol could be an ideal agent in this setting.

METHODS

Over a 43-month period, consecutive patients undergoing sphincter of Oddi manometry were studied prospectively. Sphincter of Oddi manometry was performed under general anesthesia in all but 10 patients. Standard retrograde pull-through techniques were used to examine the biliary and/or pancreatic sphincter, depending on the indication for sphincter of Oddi manometry. After the initial two pull-throughs, 5 mg of droperidol were given intravenously and measurements were repeated 5 minutes later.

RESULTS

A total of 55 patients were studied (42 women [76%], 13 men; mean age 43 years). The basal biliary sphincter pressures measured in 35 patients before and after droperidol were, respectively, 56 mm Hg and 48 mm Hg (p = 0.02); the basal pancreatic sphincter pressures measured in 22 patients before and after droperidol were, respectively, 92 mm Hg and 67 mm Hg (p = 0.29). By using a definition for sphincter of Oddi dysfunction of a basal pressure greater than 40 mm Hg, droperidol would have resulted in a change in diagnosis in 5 patients undergoing biliary manometry (one misclassified as sphincter of Oddi dysfunction, 4 misclassified as normal), and 6 patients undergoing pancreatic sphincter manometry (5 misclassified as sphincter of Oddi dysfunction, one misclassified as normal) (total 19% of procedures). No complication was associated with droperidol use.

CONCLUSIONS

Droperidol alters basal sphincter pressures, which in some patients was clinically significant and would have resulted in misclassification. Although safe and well tolerated, droperidol appears to have subtle but clinically significant effects on the sphincter of Oddi.

Effects of droperidol on the pancreatic and biliary sphincters

BACKGROUND

Performance of sphincter of Oddi manometry at ERCP is technically demanding and requires that the patient be well sedated. Droperidol is frequently administered when adequate sedation cannot be achieved with a benzodiazepine and meperidine. This study examined the effects of droperidol on the biliary and pancreatic sphincters.

METHODS

A total of 31 patients were prospectively evaluated by sphincter of Oddi manometry in the conventional retrograde fashion. Manometry was initially performed with intravenous administration of diazepam alone, diazepam plus meperidine or midazolam plus meperidine. Manometry was then repeated 5 minutes after droperidol was administered.

RESULTS

The basal pressure of the biliary sphincter and of the pancreatic sphincter were not significantly altered by droperidol. Concordance (normal vs. abnormal) between the basal sphincter pressure before and after droperidol was seen in 30 patients (97%). Droperidol also did not lead to a difference in phasic wave amplitude, duration, or frequency. Thirteen manometry tracings (42%) were judged as being qualitatively better after droperidol, whereas two (6.5%; </= p 0.001) were qualitatively better before droperidol administration.

CONCLUSIONS

Droperidol does not significantly affect sphincter of Oddi manometric parameters. It appears that it can be added to the armamentarium of agents needed for performance of sphincter of Oddi manometry. However, further study is needed to determine whether recent safety concerns with droperidol use are valid.