Effect of propofol on human sphincter of Oddi

Endoscopic approach to the patient with motility disorders of the bile duct and sphincter of Oddi

Since its original description by Oddi in 1887, the sphincter of Oddi has been the subject of much study. Furthermore, the clinical syndrome of sphincter of Oddi dysfunction (SOD) and its therapy are controversial areas. Nevertheless, SOD is commonly diagnosed and treated by physicians. This article reviews the epidemiology, clinical manifestations, and current diagnostic and therapeutic modalities of SOD.

Organ toxicity and mortality in propofol-sedated rabbits under prolonged mechanical ventilation

BACKGROUND

Prolonged administration of propofol at large doses has been implicated in propofol infusion syndrome in intensive care unit patients. In this study we investigated organ toxicity and mortality of propofol sedation at large doses in prolonged mechanically ventilated rabbits and determined the role of propofol's lipid vehicle.

METHODS

Eighteen healthy male rabbits were endotracheally intubated and sedated with propofol 2% (Group P), sevoflurane (Group S) or sevoflurane while receiving Intralipid 10% (Group SI). Sedation lasted 48 h or until death (Group P) or the maximum surviving period of Group P (Groups S and SI). The initial propofol infusion rate (20 mg x kg(-1) x h(-1)) or sevoflurane concentration (1.5%) was adjusted, if needed, to maintain a standard level of sedation. Blood biochemical analysis was performed in serial blood samples and histologic examination in the heart, lungs, liver, gallbladder, kidneys, urinary bladder, and quadriceps femoris muscle at autopsy.

RESULTS

The mortality rate was 100% (surviving period, 26-38 h) for Group P, whereas 0% for Groups S and SI. The initial propofol infusion rate had to be increased up to 65.7 +/- 4.6 mg x kg(-1) x h(-1) and sevoflurane concentration up to 4%. Serum liver function indices, lipids and creatine kinase were significantly increased (P < 0.05) in Groups P and SI and lactate was increased only in Group P, whereas amylase was increased in all groups. In Group P, histologic examination revealed myocarditis, pulmonary edema with interstitial pneumonia, hepatitis, steatosis, and focal liver necrosis, cholangitis, gallbladder necrosis, acute tubular necrosis of the kidneys, focal loss of the urinary bladder epithelium, and rhabdomyolysis of skeletal muscles; in Group S, low-grade bronchitis and incipient inflammation of the liver and the kidneys; and in Group SI, low-grade bronchitis, liver steatosis and hepatitis, and incipient inflammation of the gallbladder, kidneys, and urinary bladder.

CONCLUSIONS

Continuous infusion of 2% propofol at large doses for the sedation of rabbits undergoing prolonged mechanical ventilation induced fatal multiorgan dysfunction syndrome similar to the propofol infusion syndrome seen in humans. Our novel findings including lung, liver, gallbladder, and urinary bladder injury were also noted. The role of propofol's lipid vehicle in the manifestation of the syndrome was minor. Sevoflurane proved to be a safe alternative medication for prolonged sedation.

Investigation of relaxant effects of propofol on sheep sphincter of Oddi

BACKGROUND/AIMS

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 effects of propofol on sheep SO.

METHODS

SO rings were mounted in a tissue bath and tested for changes in isometric tension in response to propofol (10(-8)-10(-4)M) in the presence or absence of L-NAME (3 x 10(-5)M), a non-specific inhibitor of nitric oxide (NO) synthase; indomethacin (10(-5)M), an inhibitor of cyclooxygenase; glibenclamide (10(-5)M), an inhibitor of ATP-sensitive potassium channels; tetraethylammonium (3 x 10(-4)M), inhibitors of calcium-activated potassium channels; 4-aminopyridine (10(-3)M), a voltage-dependent potassium channel blocker. Furthermore, we investigated the Ca(2+) antagonist feature of propofol in precontracted SO rings by CaCl(2).

RESULTS

Carbachol (10(-9)-10(-5)M) induced concentration-dependent contraction responses in the SO rings. Propofol (10(-8)-10(-4)M) produced concentration-dependent relaxation on isolated SO rings precontracted by carbachol (10(-6)M). Preincubation of SO rings by L-NAME (3 x 10(-5)M), indomethacin (10(-5)M), glibenclamide (10(-5)M), and 4-aminopyridine (10(-3)M) did not produce a significant alteration on propofol-induced relaxation responses (p > 0.05), while preincubation by tetraethylammonium (3 x 10(-4)M) significantly decreased the propofol-induced relaxation responses (p < 0.05). Propofol (10(-8)-10(-4)M) induced concentration-dependently relaxations in precontracted isolated SO rings by CaCl(2).

CONCLUSION

The results suggest that propofol induced concentration-dependent relaxations in precontracted isolated SO rings. These relaxations are independent from NO, cyclooxygenase metabolites, and opened ATP-sensitive and voltage-dependent potassium channels. Opened Ca(2+)-sensitive K(+) channels and inhibited L-type Ca(2+) channels existing in smooth muscle by propofol can contribute to these relaxations. Propofol can be beneficial as alternative drugs for obtaining selective relaxation during SO manometry after controlled clinical studies.

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.

Normal sphincter of oddi motor function

With the introduction of endoscopic retrograde cholangiopancreatography (ERCP) manometry, the characteristics of sphincter of Oddi (SO) motor activity have been described. SO manometry is the only available method to measure SO motor activity directly and is usually performed at the time of ERCP. SO manometry is considered to be the gold standard for evaluating patients for sphincter dysfunction. This review reports the technique of SO manometry and normal values for SO manometry. SO motility is characterized by prominent phasic contractions superimposed on a tonic pressure. Elevated basal SO pressure is the most consistent and reliable criteria to diagnose SO dysfunction. Basal pressures obtained from the biliary sphincter are similar to the basal pressure obtained from the pancreatic sphincter. Abnormal SO manometric values are shown. Factors that influence SO pressures, and interpretation of SO manometric tracing are discussed. The most common and serious complication of SO manometry is post-manometry pancreatitis. In healthy volunteers with normal sphincter function, pancreatitis is almost never seen. However, in patients with SO dysfunction, the incidence of pancreatitis is high. The use of new nonperfused microtransducers may reduce this complication.

Secretin MRCP and endoscopic pancreatic manometry in the evaluation of sphincter of Oddi function: a comparative pilot study in patients with idiopathic recurrent pancreatitis

BACKGROUND

Sphincter of Oddi dysfunction plays an important etiologic role in idiopathic acute recurrent pancreatitis. Sphincter of Oddi manometry is the most accurate test of sphincter of Oddi function, but it is associated with an increased risk of post-procedure pancreatitis and is non-diagnostic in about a third of cases. Secretin MRCP has a diagnostic efficacy comparable to ERCP, but data on its sensitivity with regard to sphincter of Oddi function are lacking. The aim of this study was to compare secretin MRCP and pancreatic sphincter of Oddi manometry for evaluation of sphincter of Oddi function in patients with idiopathic acute recurrent pancreatitis.

METHODS

Eighteen consecutive patients with idiopathic acute recurrent pancreatitis underwent secretin MRCP and pancreatic sphincter of Oddi manometry/ERCP. Data from 15 patients were suitable for analysis. Fifteen subjects with asymptomatic, non-pancreatic hyperamylasemia matched for age and gender underwent secretin MRCP and served as a control group.

RESULTS

Sphincter of Oddi manometry documented sphincter dysfunction in 6/15 patients (40%) and secretin MRCP, in 4/15 patients (26.7%). Sphincter of Oddi manometry confirmed the presence of elevated basal sphincter of Oddi pressure in two of the 4 patients with abnormal and other forms of sphincter of Oddi dyskinesia in the other two. None of the control subjects had an abnormal secretin MRCP. Secretin MRCP and sphincter of Oddi manometry were concordant in 13/15 patients (86.7%); positive and negative diagnoses for sphincter of Oddi dysfunction agreed in, respectively, 81.8% and 100% (kappa value 0.706).

CONCLUSIONS

Secretin MRCP seems to be a useful noninvasive procedure for investigation of pancreatic sphincter of Oddi function, but evaluation in larger series is needed.

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.

Sedation with propofol plus midazolam versus propofol alone for interventional endoscopic procedures: a prospective, randomized study

AIM

Adequate patient sedation is mandatory for most interventional endoscopic procedures. Recent anaesthesiologic studies indicates that propofol and midazolam act synergistically in combination and therefore may be superior to sedation with propofol alone in terms of sedation efficacy, recovery and costs (due to a presumed lower total dose of propofol needed).

METHODS

A total of 239 consecutive patients undergoing therapeutic EGD or ERCP (EGD/ERCP-ratio, 1:1) randomly received either propofol alone (n=120, group A, loading dose 40-60 mg intravenously, followed by repeated doses of 20 mg) or propofol plus midazolam (n=119, group B, initial midazolam dose of 2. 5-3.5 mg intravenously, followed by repeated doses of 20 mg of propofol) for sedation. Vital signs (heart rate, blood pressure, oxygen saturation, electrocardiogram) were continuously monitored. Procedure-related parameters, the recovery time and quality (post-anaesthesia recovery score) as well as the patient's co-operation and tolerance to the procedure (visual analogue scale) were prospectively assessed.

RESULTS

Patients of group A and B were well matched with respect to demographic and clinical data, endoscopic findings, and the type of associated procedures. In group A, a mean dose of 0.25 +/- 0.13 mg.min/kg propofol was used compared to 0.20 +/- 0.09 mg.min/kg of propofol in group B (P < 0.01, plus additional 2.9 +/- 0.5 mg of midazolam). Clinically relevant changes in vital signs were observed at comparable frequencies with a lowering of the systolic blood pressure < 90 mmHg in six out of 119 patients in group B and one out of 120 patients in group A (P=0.07). The sedation efficacy was rated similarly in both groups, whereas the mean recovery time (group A, 19 +/- 7 min vs. group B, 25 +/- 8 min, P < 0.05) as well as the recovery score (post-anaesthesia recovery score group A, 8.0 +/- 1.1 vs. post-anaesthesia recovery score group B, 7.3 +/- 1.2, P < 0.001) were significantly better with propofol alone than with propofol plus midazolam.

CONCLUSION

During therapeutic endoscopy, sedation with propofol and midazolam requires a lower total dose of propofol, but otherwise has no superior sedation efficacy and is associated with a slower post-procedure recovery than sedation with propofol alone.

Gastroenterologist-administered propofol for therapeutic upper endoscopy with graphic assessment of respiratory activity: a case series

BACKGROUND

Traditional methods of sedation and analgesia for advanced endoscopic procedures can be inadequate and frequently prolong recovery room observation. Propofol is a rapidly acting agent that produces an excellent hypnotic state, but its use is typically limited to anesthesiologist-assisted cases because of the inadequacy of current monitoring standards to reliably detect early stages of respiratory depression.

METHODS

Ten patients undergoing advanced upper endoscopic procedures (endoscopic retrograde cholangiopancreatography, endoscopic ultrasound, esophageal stent placement) received a propofol infusion under the control of a second qualified gastroenterologist with advanced cardiac life support skills. Graphic assessment of respiratory activity was made by using a sidestream carbon dioxide detecting cannula. Patient satisfaction was measured with a 100 mm visual analog scale. Recovery scores were measured by standardized scoring of discharge criteria.

RESULTS

Monitoring with graphic assessment of respiratory activity detected early phases of respiratory depression, resulting in a timely decrease in the propofol infusion without significant hypoxemia, hypercapnia, hypotension, or arrhythmias. Satisfaction scores were extremely high (median score 92 of 100) and 9 of 10 patients met discharge criteria at 15 minutes after discontinuation of the propofol infusion.

CONCLUSIONS

With the use of monitoring by graphic assessment of respiratory activity, propofol infusion by a second qualified gastroenterologist for prolonged upper endoscopic procedures is safe and results in high levels of patient satisfaction with rapid recovery times.

Efficacy and safety of intravenous propofol sedation during routine ERCP: a prospective, controlled study

BACKGROUND

Adequate patient sedation is mandatory for diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). The short-acting anesthetic propofol offers certain potential advantages for endoscopic procedures, but controlled studies proving its superiority over benzodiazepines for ERCP are lacking.

METHODS

During a 6-month period 198 consecutive patients undergoing routine ERCP randomly received either midazolam (n = 98) or propofol (n = 99) for sedation. Vital signs (heart rate, blood pressure, oxygen saturation) were continuously monitored and procedure-related parameters, the recovery time and quality (recovery score) as well as the patient's cooperation and tolerance of the procedure (visual analog scales) were prospectively assessed.

RESULTS

Patients receiving propofol or midazolam were well matched with respect to demographic and clinical data, ERCP findings, and the performance of associated procedures. Propofol caused a more rapid onset of sedation than midazolam (p < 0.01). Clinically relevant changes in vital signs were observed at comparable frequencies with temporary oxygen desaturation occurring (< 85 %) in 6 patients in the propofol group and 4 patients receiving midazolam (not significant). However, an episode of apnea had to be managed by mask ventilation via an ambu bag (lasting 8 minutes) in one of the patients receiving propofol sedation. Mean recovery times as well as the recovery scores were significantly shorter with propofol (p < 0. 01). Propofol provided significantly better patient cooperation than midazolam ( p < 0.01), but procedure tolerability was rated the same by both groups of patients (not significant).

CONCLUSIONS

Intravenous sedation with propofol for ERCP is (1) more effective than sedation with midazolam, (2) safe under adequate patient monitoring, and (3) associated with a faster postprocedure recovery.

Clinical aspects of sphincter of Oddi function and dysfunction

The sphincter of Oddi (SO) functions to regulate the flow of bile and pancreatic juices as well as to prevent the reflux of duodenal contents into the pancreatobiliary system. When dysfunction of the sphincter occurs, symptoms develop relating to either the biliary or pancreatic portions of the sphincter. The mechanism of this dysfunction remains speculative. SO manometry remains the "gold standard" to correctly diagnose the disorder and stratify therapy. Division of the sphincter is effective for SO stenosis, but there is no proven therapy for SO dyskinesia.

Effects of trimebutine on sphincter of Oddi motility in patients with post-cholecystectomy pain

BACKGROUND

Trimebutine is an opiate modulator of the gastrointestinal motility that interacts with enkephalinergic receptors.

AIM

To evaluate the effects of trimebutine (50 mg intravenous injection) on the motility of the sphincter of Oddi (SO) as assessed by endoscopic manometry.

METHODS

Endoscopic manometry was performed on 15 cholecystectomized patients who presented with symptoms suggestive of SO dysfunction. Prior to the endoscopic manometry, endoscopic ultrasonography was performed in order to rule out the possible presence of a bile duct stone.

RESULTS

Injecting trimebutine resulted in a significant increase in the SO antegrade phasic contraction rate (P = 0.02). Trimebutine decreased the basal pressure of the SO (32.5 vs. 27.5 mmHg), but the difference is not statistically significant (P = 0.11). The effects of trimebutine differed depending on the basal SO motility anomalies involved, but the period of latency was similar (mean 89 s: range 30-240 s). The basal anomalies were an increased basal SO pressure of > 40 mmHg in three patients, a tachyoddia (frequency of phasic contractions (PC) > 10/min) in six patients, prolonged PC (> 10 s) in two patients and an absence of phasic contraction in one patient. The basal pressure of the SO decreased in the three patients presenting with SO hyperpressure, but returned to a normal value in one case. The frequency of the PC decreased to normal in three out of the six patients with tachyoddia. The duration of the PC returned to normal in the two patients with prolonged PC whereas their frequencies increased. Prolonged PC developed in the patient without any detectable phasic contraction.

CONCLUSIONS

Trimebutine modulates SO motility in various ways depending on the basal SO motility anomaly observed after cholecystectomy. This regulatory effect suggests the existence of encephalinergic control of SO motility.

Endoscopic retrograde cholangiopancreatography under general anesthesia: indications and results

BACKGROUND

Conscious sedation is usually used during endoscopic retrograde cholangiopancreatography (ERCP). Little is known about the indications and outcomes for ERCP in patients who cannot undergo conscious sedation and therefore require general anesthesia. We retrospectively evaluated the indications and outcome for patients undergoing ERCP who required general anesthesia at four teaching hospitals over a 2-year period.

METHODS

Of 1200 ERCPs performed over a 2-year period, 65 patients required general anesthesia. Retrospective chart analysis was undertaken to determine indications and outcomes of ERCP performed under general anesthesia. Eleven patients underwent sphincter of Oddi manometry.

RESULTS

The major indication for general anesthesia was substance abuse. Therapeutic intervention was successful in 45 of 48 patients; 6 of the 63 patients had complications, all mild and not related to the anesthesia. Sphincter of Oddi manometry was normal in 7 patients; 4 patients had elevated basal pressures.

CONCLUSIONS

ERCP under general anesthesia may be considered when conscious sedation fails to achieve a satisfactory level of sedation for a successful and safe ERCP. Procedure-related complication rates appear to be comparable if not lower with general anesthesia.