Effects of remifentanil on esophageal motility: a double-blind, randomized, cross-over study in healthy volunteers

Impact of anesthesia drugs on digestive motility measurements in humans: A systematic review

BACKGROUND AND PURPOSE

Measurement of gastro-intestinal motility is increasingly performed under general anesthesia during endoscopic or surgical procedures. The aim of the present study was to review the impact of different anesthetic agents on digestive motility measurements in humans.

METHODS

This systematic review was performed using the Medline-Pubmed and Web of Science databases. All articles published until October 2023 were screened by identification of key words. Studies were reviewed if patients had an assessment of digestive motility using conventional perfused manometry, high-resolution manometry, electronic barostat or functional lumen impedance planimetry with the use of inhaled or intravenous anesthetic anesthetic agents (propofol, ketamine, halogens, nitrous oxide, opioids, and neuromuscular blockades).

RESULTS

Four hundred and eighty-eight unique citations were identified, of which 42 studies met the inclusion criteria and were included in the present review. The impact of anesthetics was mostly studied in patients who underwent esophageal manometry. There was a heterogeneity in both the dose and timing of administration of anesthetics among the studies. Remifentanil analgesia was the most studied anesthetic drug in the literature, showing a decrease in both distal latency and lower esophageal sphincter pressure after its administration, but the impact on Chicago classification was not studied. Inhaled anesthetics administration elicited a decrease in lower esophageal sphincter pressure, but contradictory findings were shown on esophageal motility following propofol or neuromuscular blocking agents administration.

CONCLUSION

Studies of the impact of anesthetics on digestive motility remain scarce in the literature, although some agents have been reported to profoundly affect gastro-intestinal motility.

Effects of dexmedetomidine on pharyngeal swallowing and esophageal motility-A double-blind randomized cross-over study in healthy volunteers

BACKGROUND

Sedative agents increase the risk of pulmonary aspiration, where an intact swallowing function is an important defense mechanism. Dexmedetomidine is an α2 -adrenoceptor agonist widely used during procedural sedation due to beneficial properties with minimal respiratory effects. The effects of dexmedetomidine on pharyngeal swallowing and esophageal motility are not known in detail.

METHODS

To determine the effects of dexmedetomidine on pharyngeal swallowing and esophageal motility, nineteen volunteers were included in this double-blinded, randomized placebo-controlled cross-over study. Study participants received target-controlled dexmedetomidine and placebo infusions. Recordings of pressure and impedance data were acquired using a manometry and impedance solid-state catheter. Data were analyzed from three bolus swallows series: baseline, during dexmedetomidine/placebo infusion at target plasma concentrations 0.6 ng ml-1 and 1.2 ng ml-1 . Subjective swallowing difficulties were also recorded.

KEY RESULTS

On pharyngeal swallowing, dexmedetomidine affected the upper esophageal sphincter with decreased pre- and post-swallow contractile pressures and an increase in residual pressure during swallow-related relaxation. On esophageal function, dexmedetomidine decreased contractile vigor of the proximal esophagus and increased velocity of the peristaltic contraction wave. Residual pressures during swallow-related esophagogastric junction (EGJ) relaxation decreased, as did basal EGJ resting pressure. The effects on the functional variables were not clearly dose-dependent, but mild subjective swallowing difficulties were more common at the higher dose level.

CONCLUSIONS AND INFERENCES

Dexmedetomidine induces effects on pharyngeal swallowing and esophageal motility, which should be considered in clinical patient management and also when a sedative agent for procedural sedation or for manometric examination is to be chosen.

Empirical Dilation of Non-obstructive Dysphagia: Current Understanding and Future Directions

Non-obstructive dysphagia (NOD) is defined as symptomatic dysphagia in patients with negative endoscopic and radiographic workup. The management of NOD remains controversial as there is a discrepancy between different guidelines and clinical practice. Despite the lack of high-quality studies, empiric dilation for NOD is a common clinical practice among endoscopists and the approach varies between different clinical centers. In this review, we summarize the published literature on empiric dilation for NOD and propose a management algorithm for offering empiric dilation to patients presenting with dysphagia.

Effects of remifentanil on pharyngeal swallowing and esophageal motility: no impact of different bolus volumes and partial antagonism by methylnaltrexone

Remifentanil impairs swallowing, and disturbed accommodation to bolus volume may be one of the underlying causes. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. So, this study aimed to investigate if remifentanil-induced swallowing dysfunction is dependent on the bolus volume and whether the effect of remifentanil could be counteracted by methylnaltrexone, a peripherally acting opioid antagonist. Nineteen healthy volunteers were included in this double-blinded, randomized, placebo-controlled, crossover study. Study participants received target-controlled remifentanil infusions and placebo infusions in a randomized order. Methylnaltrexone was administered by intravenous injection of doses of 0.3 mg/kg. Recordings of pressure and impedance data were acquired using a combined manometry and impedance solid-state catheter. Data were analyzed from three series of bolus swallows, baseline, during study medication exposure, and 15 min after methylnaltrexone. Remifentanil induced significant effects on multiple pharyngeal and esophageal function parameters. No significant differences in remifentanil-induced swallowing dysfunction related to different bolus volumes were found. Pharyngeal effects of remifentanil were not significantly counteracted by methylnaltrexone, whereas on the distal esophageal level, effects on distension pressures were counteracted. Changes in pharyngeal and esophageal pressure flow variables were consistent with previous results on remifentanil-induced swallowing dysfunction and uniform across all bolus volumes. The effects of remifentanil on the pharyngeal level and on the proximal esophagus appear to be predominantly centrally mediated, whereas the effects of remifentanil on the distal esophagus may be mediated by both central and peripheral mechanisms.NEW & NOTEWORTHY In this randomized controlled trial, we used the "Swallow Gateway" online platform to analyze the effects of remifentanil on pharyngeal and esophageal swallowing. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. By using methylnaltrexone, we demonstrated that effects of remifentanil on pharyngeal swallowing were predominantly centrally mediated, whereas its effects on the distal esophagus may be mediated by both central and peripheral mechanisms.

Same-day opioid administration in opiate naïve patients is not associated with opioid-induced esophageal dysfunction (OIED)

BACKGROUND

Opioid-induced esophageal dysfunction (OIED) is a recognized complication of chronic opioid use. However, the impact of acute opioid administration on esophageal motility remains unclear.

METHODS

Opioid naïve patients with high-resolution manometry (HRM) <480 min following esophagogastroduodenoscopy (EGD) (opioid-HRM) and a control group with HRM <36 h prior to EGD between January 1, 2016, and November 10, 2018, from a single institution were identified. EGDs were performed exclusively with versed and fentanyl.

KEY RESULTS

One hundred and seventy-four patients were identified, with 83 (47.7%) opioid-HRM and 91 (52.3%) controls. Mean time from EGD to HRM was 229 (78-435) min. Baseline clinical features and HRM indications were similar between opioid-HRM and controls. Chicago classification v3.0 defined HRM findings were similar between groups. Major motility disorders as defined by the Chicago classification v3.0 occurred at a similar frequency among opioid-HRM and controls (27.7% vs. 36.3%, p = 0.23). Mean distal contractile integrity (DCI) was higher in opioid-HRM (1939.3 ± 1318.9 vs. 1792.2 ± 2062.3 mmHg∙cm∙s, p = 0.043), but maximum DCI, distal latency, and integrated relaxation pressure did not differ between groups. Subgroup analysis assessing time and dose dependency did not identify differences in individual manometric parameters and Chicago classification v3.0 diagnosis between patients with HRM <240 min after EGD, >240 min after EGD, ≥125 mcg of IV fentanyl, <125 mcg IV fentanyl and controls.

CONCLUSIONS AND INFERENCES

Same-day acute opioid administration did not affect HRM findings in opioid naïve patients. Studies assessing the pathophysiology of and duration-dependent relationship with opioids in OIED are needed.

Codeine induces increased resistance at the esophagogastric junction but has no effect on motility and bolus flow in the pharynx and upper esophageal sphincter in healthy volunteers: A randomized, double-blind, placebo-controlled, cross-over trial

BACKGROUND

Chronic opioid use can induce esophageal dysfunction with symptoms resembling achalasia and a manometric pattern of esophagogastric junction-outflow obstruction (EGJ-OO). However, the effect of opioids in acute setting on pharyngeal function and esophageal body contractility has not been investigated.

METHODS

After positioning the high-resolution impedance manometry (HRiM) catheter, codeine (60 mg) or placebo (glucose syrup) was infused intragastrically. Forty-five minutes post-infusion, participants received liquid, semi-solid, and solid boluses to assess esophageal and pharyngeal function. HRiM analysis was performed adhering to the Chicago classification v3.0. (CC v3.0). Pressure flow analysis (PFA) for the esophageal body and the pharynx was performed using the SwallowGateway™ online platform.

KEY RESULTS

Nineteen healthy volunteers (HV) [5 male; age 38.3] were included. After codeine administration, higher integrated relaxation pressure 4 s values resulted in significantly reduced deglutitive EGJ relaxation and distal latency was significantly shorter. Distal contractility was similar in both conditions. Bolus flow resistance at the EGJ and distention pressures increased significantly after codeine infusion. Based on CC v3.0, acute infusion of codeine induced EGJ-OO in six HV (p = 0.0003 vs. placebo). Codeine administration induced no significant alterations in any of the pharyngeal PFA metrics.

CONCLUSIONS & INFERENCES

In HV, acute administration of codeine increased bolus resistance at the EGJ secondary to induced incomplete EGJ relaxation leading to major motility disorders in a subset of subjects including EGJ-OO. However, an acute single dose of codeine did not affect motility or bolus flow in pharynx and UES. ClinicalTrials.gov number, NCT03784105.

Opioid-induced esophageal dysfunction

PURPOSE OF REVIEW

Chronic opioid use is common and can cause opioid-induced esophageal dysfunction (OIED). We will discuss the pathophysiology, diagnosis, and management of OIED.

RECENT FINDINGS

OIED is diagnosed based on symptoms, opioid use, and manometric evidence of distal esophageal spasm, esophagogastric junction outflow obstruction, achalasia type III, or jackhammer esophagus. Chronic opioid use appears to interfere with inhibitory signals involved in control of esophageal motility, allowing for unchecked excitatory stimuli, and leading to spastic contractility and impaired esophagogastric junction relaxation. Patients may present with dysphagia and chest pain. OIED is significantly more prevalent in patients taking the stronger opioids oxycodone and hydrocodone compared with the weaker opioid tramadol. Based on 24-h morphine equivalent doses, patients with OIED take higher opioid doses than those without OIED. Impaired inhibitory signaling was recently demonstrated in a study showing reduced deglutitive inhibition during multiple rapid swallows in patients taking opioids.

SUMMARY

OIED is frequent in chronic opioid users undergoing manometry for esophageal symptoms, especially at higher doses or with stronger opioids. OIED appears to be due to impaired inhibitory signals in the esophagus. Opioid cessation or dose reduction is recommended, but studies examining management of OIED are lacking.

Opioids Interfere With Deglutitive Inhibition Assessed by Response to Multiple Rapid Swallows During High-Resolution Esophageal Manometry

INTRODUCTION

Normal response to multiple rapid swallows (MRS) during high-resolution esophageal manometry is deglutitive inhibition; opioids may interfere with this. The aim of this study was to evaluate the response to MRS in patients on opioids, not on opioids, and healthy controls.

METHODS

Response to MRS was evaluated for complete vs impaired inhibition in 72 chronic opioid users, 100 patients not on opioids, and 24 healthy controls.

RESULTS

Impaired deglutitive inhibition was significantly more frequent in chronic opioid users compared with patients not on opioids and healthy controls (54% vs 14% vs 0%; P < 0.0001).

DISCUSSION

Impaired deglutitive inhibition during MRS is frequent in opioid users, supporting that opioids interfere with esophageal inhibitory signals.

Performing High-resolution Impedance Manometry After Endoscopy With Conscious Sedation Has Negligible Effects on Esophageal Motility Results

Background/Aims

High-resolution manometry (HRM) performed without sedation is the standard procedure. However, some patients cannot tolerate transnasal placement of the manometry catheter. We aim to assess the practice of performing manometry after endoscopy with conscious sedation by evaluating its impact on esophageal motility findings.

Methods

Twelve asymptomatic adult volunteers and 7 adult patients completed high-resolution impedance manometry (HRIM) approximately 1 hour after conscious sedation with midazolam and fentanyl (post-sedation) and again on a different day with no-sedation. The nosedation HRIM involved 2 series of swallows separated in time by 20 minutes (no-sedation-1 and no-sedation-2) for the volunteers; patients completed only 1 series of swallows for no-sedation HRM.

Results

A motility diagnosis of normal motility was observed in all 12 volunteers post-sedation. Two volunteers had a diagnosis of borderline ineffective esophageal motility, one during the no-sedation-1 period and the other during the no-sedation-2 period; all of the other no-sedation HRIM studies yielded a normal motility diagnosis. Six of seven patients had the same diagnosis in both no-sedation and post-sedation HRM, including 1 distal esophageal spasm, 3 achalasia (2 type II and 1 type III), and 2 esophagogastric junction outflow obstruction. Only one patient's HRM classification changed from ineffective esophageal motility at no-sedation to normal esophageal motility at post-sedation.

Conclusions

Performing HRIM after endoscopy with conscious sedation had minimal clinical impact on the motility diagnosis or motility parameters. Thus, this approach may be a viable alternative for patients who cannot tolerate unsedated catheter placement.

Opioid-Induced Foregut Dysfunction

The impact of opioid use on the lower gastrointestinal tract is well described, but recent opioid crisis has caused increased awareness of the detrimental effects of these drugs on esophageal and gastroduodenal motility. Opioid use has been associated with increased incidence of spastic esophageal motility disorders and gastroduodenal dysfunction. Opioid receptors are present with high abundance in the myenteric and submucosal plexus of the enteric nervous system. Activation of these receptors leads to suppressed excitability of the inhibitory musculomotor neurons and unchecked tonic contraction of the autogenic musculature (such as the lower esophageal sphincter and the pylorus).

A concise review of opioid-induced esophageal dysfunction: is this a new clinical entity?

Opioids have become the most widely prescribed analgesics in Western countries. Opioid-induced bowel dysfunction is a widely known adverse effect, with constipation the most common manifestation. Most of the opioid-related effects occur in the stomach, small intestine, and colon and have been widely studied. However, the effects related to esophageal motility are less known. Recently published retrospective studies have suggested that long-term use of opioids can cause esophageal motility dysfunction, reflecting symptoms similar to motility disorders, such as achalasia and functional esophagogastric junction outflow obstruction. The most common manometric findings, as reported in the literature, for patients with opioid-induced dysphagia undergoing long-term therapy with these drugs are impaired lower esophageal sphincter relaxation, high amplitude/velocity, and simultaneous esophageal waves, higher integrated relaxation pressure, lower distal latency, and the esophageal contractility can be normal, hypercontractile, or premature. Based on these studies, a new clinical entity known as opioid-induced esophageal dysfunction has been postulated. For these patients, the diagnostic method of choice is high-resolution manometry, although other causes should be ruled out through endoscopy or Computed Tomography (CT). The best therapeutic option for these patients is withdrawal of the opioid; however, this is not always possible, and other options need to be investigated, such as pneumatic dilation and botulinum toxin injection, considering the risks versus the benefits.

Effects of remifentanil on esophageal and esophagogastric junction (EGJ) bolus transit in healthy volunteers using novel pressure-flow analysis

BACKGROUND

Remifentanil is associated with subjective dysphagia and an objective increase in aspiration risk. Studies of opioid effects have shown decreased lower esophageal sphincter relaxation. We assessed bolus transit through the esophagus and esophagogastric junction (EGJ) during remifentanil administration using objective pressure-flow analysis.

METHODS

Data from 11 healthy young participants (23±3 years, 7 M) were assessed for bolus flow through the esophagus and EGJ using high-resolution impedance manometry (Manoscan™, Sierra Scientific Instruments, Inc., LES Angeles, CA, USA) with 36 pressure and 18 impedance segments. Data were analyzed for esophageal pressure topography and pressure-flow analysis using custom Matlab analyses (Mathworks, Natick, USA). Paired t tests were performed with a P-value of < .05 regarded as significant.

KEY RESULTS

Duration of bolus flow through (remifentanil/R 3.0±0.3 vs baseline/B 5.0 ± 0.4 seconds; P < .001) and presence at the EGJ (R 5.1 ± 0.5 vs B 7.1 ± 0.5 seconds; P = .001) both decreased during remifentanil administration. Distal latency (R 5.2 ± 0.4 vs B 7.5 ± 0.2 seconds; P < .001) and distal esophageal distension-contraction latency (R 3.5 ± 0.1 vs B 4.7 ± 0.2 seconds; P < .001) were both reduced. Intrabolus pressures were increased in both the proximal (R 5.3 ± 0.9 vs B 2.6 ± 1.3 mm Hg; P = .01) and distal esophagus (R 8.6 ± 1.7 vs B 3.1 ± 0.8 mm Hg; P = .001). There was no evidence of increased esophageal bolus residue.

CONCLUSIONS AND INFERENCES

Remifentanil-induced effects were different for proximal and distal esophagus, with a reduced time for trans-sphincteric bolus flow at the EGJ, suggestive of central and peripheral μ-opioid agonism. There were no functional consequences in healthy subjects.

Impact of thoracic surgery on esophageal motor function-Evaluation by high resolution manometry

BACKGROUND

Alteration of esophageal function is a potential risk factor for postoperative complications in thoracic surgery. This prospective study investigates esophageal motility and function during and after thoracic procedures via high resolution manometry (HRM) and impedance technology with spatiotemporal representation of pressure data.

METHODS

Twelve consecutive patients eligible for elective thoracic surgery underwent preoperative and postoperative (48 hours and 7 days) esophageal HRM. Swallowing acts were carried out with 5 mL of water, 10 mL of water and 1 cm³ bread in physiological posture to evaluate distal contraction integral (DCI). Length and location of contractile integrity breaks were measured by investigators blinded to the form of surgical intervention. The impact of surgical procedures on esophageal motility was quantified according to current Chicago Classification (CC) criteria. Pre-, intra- and postoperative 24-hour multi-channel impedance pH-metry (MII-pH) was performed to further analyze gastroesophageal reflux patterns.

RESULTS

All patients were investigated 48 hours prior to and 7 days after thoracic procedures, with a total of n=675 swallowing acts being included in our study. Increased motility patterns of the tubular esophagus occurred temporally 48 hours postoperatively. DCI 48 hours after surgery increased significantly (5 mL, P=0.049; solid, P=0.014) and returned to baseline values after seven days (5 mL, P=0.039; solid, P=0.039). Break length was significantly reduced 48 hours postoperatively, especially in the proximal esophageal segment (transition zone). Follow-up measurements after another week were comparable to preoperative baseline findings. The perioperative MII-pH measurement showed numerous artifacts caused by intubation and ventilation during surgery also with increasing short and frequent acidic reflux episodes.

CONCLUSIONS

Thoracic procedures cause a transient modulation of esophageal peristalsis with postoperative increased contractility of the tubular esophagus, presumably without affecting intraesophageal reflex arcs. Although limited by the number of patients, we can conclude on our data that postoperative esophageal hypomotility is unlikely to promote secondary pulmonary complications.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.