Patient-controlled analgesia and sedation with alfentanyl versus fentanyl for colonoscopy: a randomized double blind study

A New Method for Comprehensive Analysis of Benzodiazepine, Opioid, and Propofol Interactions and Dose Selection Rationales in Gastrointestinal Endoscopy Sedation

BACKGROUND

The aim of this study was to explore a new method for determining optimal dosing regimens for combinations of propofol, midazolam, and an opioid to achieve rapid on- and off-set of deep sedation.

METHODS

We simulated 16 published dosing regimens using a well-validated pharmacodynamic model. The study was divided into 2 parts. First, the regimen that best provided deep sedation and rapid recovery was selected. A deep sedation-time area-under-the-curve (AUC) method was used to compare published dosing regimens; a higher AUC indicated better sedation and faster recovery. Second, subgroup analysis of the best-performing dosing regimen was undertaken better to understand how each drug affected patient recovery.

RESULTS

The AUC method identified a combination of midazolam 1 mg, alfentanil 500 µg, and propofol target infusion effect-site concentration (Ce) 2 µg mL -1 as the optimal regimen ( P < .01). Propofol correlated with high probability of sedation and increased AUC (R 2 = 0.53), whereas midazolam had a significant impact on time to return of consciousness (R 2 = 0.86). Subgroup analysis indicated that regimens consisting of a fixed dose of alfentanil and either 5 µg mL -1 Ce propofol, or 1 mg midazolam with 3-5 µg mL -1 Ce of propofol, or 2 mg midazolam with 2 µg mL -1 Ce propofol provided adequate sedation and rapid recovery. Midazolam >3 mg greatly prolonged recovery.

CONCLUSIONS

This study used a clinically relevant method and model simulation to determine suitable sedation regimens for use in gastrointestinal endoscopy. A balanced propofol, midazolam, and an opioid should be used. The AUC method was capable of providing objective assessments for model selection.

Causes of intraprocedural discomfort in colonoscopy: a review and practical tips

Colonoscopy is a commonly performed procedure in the United Kingdom and the gold standard for diagnosis and therapy in the gastrointestinal tract. Increased levels of pain during colonoscopy have been associated with reduced completion rates and difficulties in maintaining attendance for repeat procedures. Multiple factors play a role in causing discomfort intra-procedurally: patient factors, such as gender, anatomy and pre-procedure anxiety; operator factors, such as patient position and level of experience and other factors, such as bowel preparation and total procedure time. A literature search was performed to identify papers that explained how patient, operator and endoscopy factors influenced pain and discomfort in endoscopy. A further search then also identified papers describing solutions to pain and discomfort that have been explored. After review of the literature, key methods are selected and discussed in this paper. Solutions and aids that can resolve and improve pain and discomfort include endoscopic methods such as variable stiffness and ultrathin scopes. Operator improvements in techniques and ergonomics alongside the use of newer technologies such as propelled endoscopy, computer-assisted endoscopy and task distraction. To improve patient experience and outcomes, the investigation and research into improving techniques to reduce pain is crucial. This review aims to identify the modifiable and non-modifiable factors associated with intra-procedural discomfort during colonoscopy. We discuss established methods of improving pain during colonoscopy, in addition to newer technologies to mitigate associated discomfort.

The safety and efficacy of alfentanil combined with midazolam in fiberoptic bronchoscopy sedation: A randomized, double-blind, controlled trial

Sedation is recommended by most guidelines to be offered to all patients undergoing diagnostic flexible bronchoscopy (DFB) without contraindications, and the most commonly reported regimen is midazolam in combination with a short-acting opioid (fentanyl or alfentanil) to provide both sedative and antitussive effects. However, the optimal dose or ideal regimen of the combination therapy with midazolam and opioids has not yet been found. So this randomized, double-blinded clinical trial was designed and registered (ChiCTR2100049052) to assess the safety and efficacy of midazolam combined with different doses of alfentanil in DFB sedation. Our study showed that relative high doses of alfentanil (10–25 μg/kg) combined with a fixed low dose of midazolam can markedly reduce hemodynamic fluctuations, cough reactions, patients’ discomforts, and improve their satisfaction in a dose-dependent manner during DFB, with no significant increase in the desaturation risks.

Sedative effect of remimazolam combined with alfentanil in colonoscopic polypectomy: a prospective, randomized, controlled clinical trial

Background

Remimazolam is a newer benzodiazepine with properties of rapid onset, short duration of action, and fast recovery. Our study was to evaluate the effects of different doses of remimazolam combined with alfentanil in colonoscopic polypectomy.

Methods

One hundred twenty patients were randomly divided into four groups: alfentanil and propofol (AP) group, alfentanil and remimazolam 0.1 mg/kg (AR1 group), 0.15 mg/kg (AR2 group), or 0.2 mg/kg (AR3 group). Patients in the four groups received alfentanil 10 μg/kg, followed by propofol 2 mg/kg and three dosages of remimazolam. Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scale, heart rate (HR), oxygen saturation (SpO₂), respiratory rate (RR), bispectral index (BIS) values and mean arterial pressure (MAP) were collected at intervals of 5 min and analyzed at different time points: before anesthesia (T0), 5 min (T1), 10 min (T2), 15 min after anesthesia (T3) and at the end of surgery (T4). The average MAP was calculated utilizing the average of all MAP values. The primary outcome was the success rate of sedation. Secondary outcomes included time to full alert and adverse events.

Results

The success rate of sedation was 100% among the four groups. The incidence of hypotension was significantly decreased (all P < 0.05) and the average MAP was higher in AR1-AR3 groups than AP group (all P < 0.001). None of the patients developed bradycardia or hypertension during surgery in all study groups. BIS values were higher (all P < 0.001) and the time to full alert was statistically shorter in AR1-AR3 groups (all P < 0.05) compared with the AP group. The MOAA/S score in AR1 was higher than AR2 (P < 0.05) and the AR3 group (P < 0.05) at T1 and BIS values in the AR1 group were significantly higher than AR3 group (P < 0.05) at T4.

Conclusions

Remimazolam combined with alfentanil have a non-inferior sedative effect than propofol during the colonoscopic polypectomy. Moreover, this combination of two short-acting drugs might be a safer alternative.

Trial registration

The clinical trial was registered on (16/05/2021, ChiCTR2100046492).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01805-3.

Guidelines for sedation in gastroenterological endoscopy (second edition)

Sedation in gastroenterological endoscopy has become an important medical option in routine clinical care. Here, the Japan Gastroenterological Endoscopy Society and the Japanese Society of Anesthesiologists together provide the revised "Guidelines for sedation in gastroenterological endoscopy" as a second edition to address on-site clinical questions and issues raised for safe examination and treatment using sedated endoscopy. Twenty clinical questions were determined and the strength of recommendation and evidence quality (strength) were expressed according to the "MINDS Manual for Guideline Development 2017." We were able to release up-to-date statements related to clinical questions and current issues relevant to sedation in gastroenterological endoscopy (henceforth, "endoscopy"). There are few reports from Japan in this field (e.g., meta-analyses), and many aspects have been based only on a specialist consensus. In the current scenario, benzodiazepine drugs primarily used for sedation during gastroenterological endoscopy are not approved by national health insurance in Japan, and investigations regarding expense-related disadvantages have not been conducted. Furthermore, including the perspective of beneficiaries (i.e., patients and citizens) during the creation of clinical guidelines should be considered. These guidelines are standardized based on up-to-date evidence quality (strength) and supports on-site clinical decision-making by patients and medical staff. Therefore, these guidelines need to be flexible with regard to the wishes, age, complications, and social conditions of the patient, as well as the conditions of the facility and discretion of the physician.

Feasibility of a transmucosal sublingual fentanyl tablet as a procedural pain treatment in colonoscopy patients: a prospective placebo-controlled randomized study

Since patients often experience pain and unpleasantness during a colonoscopy, the present study aimed to evaluate the efficacy and safety of sublingually administered fentanyl tablets for pain treatment. Furthermore, since the use of intravenous drugs significantly increases colonoscopy costs, sublingual tablets could be a cost-effective alternative to intravenous sedation. We conducted a prospective placebo-controlled randomized study of 158 patients to evaluate the analgesic effect of a 100 µg dose of sublingual fentanyl administered before a colonoscopy. Pain, sedation, nausea, and satisfaction were assessed during the colonoscopy by the patients as well as the endoscopists and nurses. Respiratory rate and peripheral arteriolar oxygen saturation were monitored throughout the procedure. There were no differences between the fentanyl and placebo groups in any of the measured variables. The median pain intensity values, as measured using a numerical rating scale, were 4.5 in the fentanyl group and 5 in the placebo group. The sedation and oxygen saturation levels and the respiratory rate did not differ between the groups. The majority of the colonoscopies were completed.Our results indicate that a 100 µg dose of sublingual fentanyl is not beneficial compared to the placebo in the treatment of procedural pain during a colonoscopy.

A Response Surface Model Exploration of Dosing Strategies in Gastrointestinal Endoscopies Using Midazolam and Opioids

Classical midazolam-opioid combination for gastrointestinal endoscopy sedation has been adopted for decades. Dosing regimens have been studied but most require fixed dosing intervals. We intend to use a sophisticated pharmacodynamic tool, response surface model (RSM), to simulate sedation using different regimens. RSM can predict patient's response during different phases of the examination and predict patient's wake-up time with precision and without the need for fixed dosing intervals. We believe it will aid physicians in guiding their dosing strategy and timing.The study is divided into 2 parts. The first part is the full Greco RSMs development for 3 distinct phases: esophagogastroduodenoscopy (EGD), colonoscopy, and intersession (the time lapse between procedures). Observer's Assessment of Alertness Score (OAA/S) is used to assess patient response. The second part simulates 6 regimens with different characteristics using the RSMs: midazolam only, balanced midazolam and opioids, high-dose opioids and midazolam, low-dose midazolam with high-dose opioids, high-dose midazolam and low-dose opioids, and finally midazolam with continuous opioid infusion. Loss of response at 95% probability for adequate anesthesia during examination and return of consciousness at 50% probability during intersession was selected for simulation purposes.The average age of the patient population is 49.3 years. Mean BMI is 21.9 ± 2.3 kg/m. About 56.7% were females and none received prior abdominal surgery. The cecal intubation rate was 100%. Only 1 patient (3%) developed temporary hypoxemia, which was promptly managed with simple measures. The RSMs for each phase showed significant synergy between midazolam and alfentanil. The balanced midazolam and alfentanil combination provided adequate anesthesia and most rapid return of consciousness. The awakening time from the final drug bolus was 7.4 minutes during EGD and colonoscopy stimulation, and 9.1 minutes during EGD simulation.Simulation of regimens with different characteristics gives insights on dosing strategies. A balanced midazolam-alfentanil regimen is adequate in providing good anesthetic depth and most rapid return of consciousness. We believe with the aid of our RSM, clinicians can perform sedation with more flexibility and precision.

Sedation in the Endoscopy Suite

OPINION STATEMENT

Sedation practices in the endoscopy suite have changed dramatically in the decades since the introduction of routine colonoscopy and esophagogastroduodenoscopy (EGD). Patients initially received moderate sedation (or even no sedation), but now frequently receive monitored anesthesia care (MAC). This significant shift has introduced anesthesiologists to the endoscopy suite along with new sedative medications and safety concerns. Appreciating the ramifications of this change requires an understanding of sedation depth, patient selection, drug use, sedation delivery, patient monitoring, recovery from sedation, and patient outcomes. Furthermore, the changing landscape of healthcare quality and reimbursement challenges us to provide the best possible care for our patients in the most economical way possible. The endoscopy suite is a unique sedation environment, and it is the purpose of this article to review those elements that contribute to a uniquely demanding work environment.

Sedation-analgesia in elective colonoscopy: propofol-fentanyl versus propofol-alfentanil

BACKGROUND AND OBJECTIVES

Sedation-analgesia is recommended for comfortable colonoscopy procedures, which are invasive and can be painful. This study aimed to compare the combinations of propofol-alfentanil and propofol-fentanyl for sedation-analgesia in elective colonoscopy patients.

METHODS

This prospective and randomized study was planned in ASA I-II groups and included 80 patients between the ages of 18 and 65 years. Sedation-analgesia induction was performed as 1 μg.kg-1 fentanyl, 1 mg.kg-1 propofol in the propofol-fentanyl group (Group PF) and 10 μg.kg-1 alfentanil, 1 mg.kg-1 propofol in the propofol-alfentanil group (Group PA). Patients’ scores were limited to 3-4 values on the Ramsey Sedation Scale (RSS) by 0.5 mg.kg-1 bolus additional doses of propofol in sedation-analgesia maintenance. We recorded demographical data, heart rate, mean arterial pressure (MAP), oxygen saturation of hemoglobin (SpO2), RSS value, colonoscopy time, total dose of propofol, complications, recovery time, and discharge time, as well as colonoscopist and patient satisfaction scores.

RESULTS

MAP at the 15th minute in Group PA was signifi cantly higher than in Group PF (p = 0.037). Group PA’s beginning mean heart rate was higher than the mean heart rate at subsequent readings (p = 0.012, p = 0.002). The mean total propofol dose of Group PA was signifi cantly higher than the total dose of Group PF (p = 0.028). The mean recovery time of Group PA was signifi cantly longer than that of Group PF (p = 0.032).

CONCLUSION

Fentanyl provides better operative conditions and reduces the need for additional propofol doses. These advantages cause a shorter recovery time. Therefore, propofol-fentanyl is superior to the propofol-alfentanil for sedation-analgesia in colonoscopy.

Is "really conscious" sedation with solely an opioid an alternative to every day used sedation regimes for colonoscopies in a teaching hospital? Midazolam/fentanyl, propofol/alfentanil, or alfentanil only for colonoscopy: a randomized trial

BACKGROUND

We investigated the satisfaction of patients and endoscopists and concurrently safety aspects of an "alfentanil only" and two clinically routinely used sedation regimes in patients undergoing colonoscopy in a teaching hospital.

METHODS

One hundred and eighty patients were prospectively randomized in three groups: M (midazolam/fentanyl), A (alfentanil), and P (propofol/alfentanil); M and A were administered by an endoscopy nurse, P by an anesthesia nurse. Interventions, heart rate, saturation, electrocardiogram, noninvasive blood pressure, and expiratory CO₂ were monitored using video assistance. After endoscopy, patients and gastroenterologists completed questionnaires about satisfaction.

RESULTS

A high level of satisfaction was found in all groups, with patients in group P being more satisfied with their sedation experience (median 1.75, p < 0.001). Gastroenterologist satisfaction varied not significantly between the three alternatives. Patients in group A felt less drowsy, could communicate more rapidly than patients in both other groups, and met discharge criteria immediately after the end of the procedure. Respiratory events associated with sedation were observed in 43% patients in group M, 47% in group P, but only 13% in group A (p < 0.001).

CONCLUSIONS

These results suggest that alfentanil could be an alternative for sedation in colonoscopy even in the setting of a teaching hospital. It results in satisfied patients easily taking up information, and recovering rapidly. Although one might expect to observe more respiratory depression with an "opioid only" sedation technique without involvement of anesthesia partners, respiratory events were less frequent than when other methods were used.

Sedation-analgesia in elective colonoscopy: propofol-fentanyl versus propofol-alfentanil

BACKGROUND AND OBJECTIVES

Sedation-analgesia is recommended for comfortable colonoscopy procedures, which are invasive and can be painful. This study aimed to compare the combinations of propofol-alfentanil and propofol-fentanyl for sedation-analgesia in elective colonoscopy patients.

METHODS

This prospective and randomized study was planned in ASA I-II groups and included 80 patients between the ages of 18 and 65 years. Sedation-analgesia induction was performed as 1 μg.kg(-1) fentanyl, 1mg.kg(-1) propofol in the propofol-fentanyl group (Group PF) and 10 μg.kg(-1) alfentanil, 1mg.kg(-1) propofol in the propofol-alfentanil group (Group PA). Patients' scores were limited to 3-4 values on the Ramsey Sedation Scale (RSS) by 0.5mg.kg(-1) bolus additional doses of propofol in sedation-analgesia maintenance. We recorded demographical data, heart rate, mean arterial pressure (MAP), oxygen saturation of hemoglobin (SpO2), RSS value, colonoscopy time, total dose of propofol, complications, recovery time, and discharge time, as well as colonoscopist and patient satisfaction scores.

RESULTS

MAP at the 15(th) minute in Group PA was significantly higher than in Group PF (p = 0.037). Group PA's beginning mean heart rate was higher than the mean heart rate at subsequent readings (p = 0.012, p = 0.002). The mean total propofol dose of Group PA was significantly higher than the total dose of Group PF (p = 0.028). The mean recovery time of Group PA was significantly longer than that of Group PF (p = 0.032).

CONCLUSION

Fentanyl provides better operative conditions and reduces the need for additional propofol doses. These advantages cause a shorter recovery time. Therefore, propofol-fentanyl is superior to the propofol-alfentanil for sedation-analgesia in colonoscopy.

Sedation in gastrointestinal endoscopy: current issues

Diagnostic and therapeutic endoscopy can successfully be performed by applying moderate (conscious) sedation. Moderate sedation, using midazolam and an opioid, is the standard method of sedation, although propofol is increasingly being used in many countries because the satisfaction of endoscopists with propofol sedation is greater compared with their satisfaction with conventional sedation. Moreover, the use of propofol is currently preferred for the endoscopic sedation of patients with advanced liver disease due to its short biologic half-life and, consequently, its low risk of inducing hepatic encephalopathy. In the future, propofol could become the preferred sedation agent, especially for routine colonoscopy. Midazolam is the benzodiazepine of choice because of its shorter duration of action and better pharmacokinetic profile compared with diazepam. Among opioids, pethidine and fentanyl are the most popular. A number of other substances have been tested in several clinical trials with promising results. Among them, newer opioids, such as remifentanil, enable a faster recovery. The controversy regarding the administration of sedation by an endoscopist or an experienced nurse, as well as the optimal staffing of endoscopy units, continues to be a matter of discussion. Safe sedation in special clinical circumstances, such as in the cases of obese, pregnant, and elderly individuals, as well as patients with chronic lung, renal or liver disease, requires modification of the dose of the drugs used for sedation. In the great majority of patients, sedation under the supervision of a properly trained endoscopist remains the standard practice worldwide. In this review, an overview of the current knowledge concerning sedation during digestive endoscopy will be provided based on the data in the current literature.

Comparison between the recovery time of alfentanil and fentanyl in balanced propofol sedation for gastrointestinal and colonoscopy: a prospective, randomized study

Background

There is increasing interest in balanced propofol sedation (BPS) titrated to moderate sedation (conscious sedation) for endoscopic procedures. However, few controlled studies on BPS targeted to deep sedation for diagnostic endoscopy were found. Alfentanil, a rapid and short-acting synthetic analog of fentanyl, appears to offer clinically significant advantages over fentanyl during outpatient anesthesia.

It is reasonable to hypothesize that low dose of alfentanil used in BPS might also result in more rapid recovery as compared with fentanyl.

Methods

A prospective, randomized and double-blinded clinical trial of alfentanil, midazolam and propofol versus fentanyl, midazolam and propofol in 272 outpatients undergoing diagnostic esophagogastroduodenal endoscopy (EGD) and colonoscopy for health examination were enrolled. Randomization was achieved by using the computer-generated random sequence. Each combination regimen was titrated to deep sedation. The recovery time, patient satisfaction, safety and the efficacy and cost benefit between groups were compared.

Results

260 participants were analyzed, 129 in alfentanil group and 131 in fentanyl group. There is no significant difference in sex, age, body weight, BMI and ASA distribution between two groups. Also, there is no significant difference in recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between two groups. Though deep sedation was targeted, all cardiopulmonary complications were minor and transient (10.8%, 28/260). No serious adverse events including the use of flumazenil, assisted ventilation, permanent injury or death, and temporary or permanent interruption of procedure were found in both groups. However, fentanyl is New Taiwan Dollar (NT$) 103 (approximate US$ 4) cheaper than alfentanil, leading to a significant difference in total cost between two groups.

Conclusions

This randomized, double-blinded clinical trial showed that there is no significant difference in the recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between the two most common sedation regimens for EGD and colonoscopy in our hospital. However, fentanyl is NT$103 (US$ 4) cheaper than alfentanil in each case.

Trial registration

Institutional Review Board of Buddhist Tzu Chi General Hospital (IRB097-18) and Chinese Clinical Trial Registry (ChiCTR-TRC-12002575)

Analgesia without sedatives during colonoscopies: worth considering?

Colonoscopy is a proven method for bowel cancer screening and is often experienced as a painful procedure. Today, there are two main strategies to facilitate colonoscopy. First, deep sedation results in satisfied patients but increases sedation-associated risks and raises costs for healthcare providers. Second, there is the advocacy for colonoscopies without any form of sedation. This might be an option for a special group of patients, but does not hold true for everybody. Following Moerman’s hypothesis: “If pain is the crucial point, why do we need sedation?” this review shows the analgesic options for a painless procedure, increasing success rates without increasing risk of sedation. There are two agents, with the potential to be a nearly ideal analgesic agent for colonoscopy: alfentanil and nitrous oxide (N₂O). Administration of either substance causes the patient to be comfortable yet alert and facilitates a short turnover. Advantages of these drugs include rapid onset and offset of action, analgesic and anxiolytic effects, ease of titration to desired level, rapid recovery, and an excellent safety profile.

A randomized double-blind placebo-controlled trial to evaluate the value of a single bolus intravenous alfentanil in CT colonography

BACKGROUND

Although CT colonography is a less invasive alternative for colonoscopy for the detection of colorectal polyps and cancer, procedural pain is common. In several studies, CT colonography pain and burden is higher than in colonoscopy. Apart from discomfort, anxiety and its related stress-induced peri- procedural side effects, this may influence the adherence for CT colonography as a possible screening tool for colorectal cancer. We hypothesize that a single bolus intravenous alfentanil will give a clinically relevant reduction in maximum pain defined as at least 1.3 point reduction on an 11-point numeric rating scale (NRS).

METHODS/DESIGN

A randomized double-blind placebo-controlled trial in which patients scheduled for elective CT colonography in a single tertiary centre are eligible for inclusion. The first 90 consenting patient will be block-randomized to either the alfentanil group or the placebo group. Before bowel insufflation, the alfentanil group receives a single bolus intravenous alfentanil 7.5 μg/kg dissolved in 0.9% NaCl, while the placebo group receives an intravenous bolus injection of pure 0.9% NaCl. For both groups an equal amount of fluid per kilogram (75 μL/kg) is injected. The primary outcome is the difference in maximum pain on an 11-point NRS. Secondary outcomes include: pain and burden of different CT colonography aspects, side effects, procedural time and recovery time. For the primary outcome an independent samples t-test is performed and a P value<0.05 is considered statistically significant.

DISCUSSION

This study will provide evidence whether a single bolus intravenous alfentanil gives a clinically relevant reduction in maximum pain during CT colonography.

TRIAL REGISTRATION

Netherlands Trial Register (NTR): NTR2902. This trial will be conducted in accordance with the protocol and in compliance with the moral, ethical, and scientific principles governing clinical research as set out in the Declaration of Helsinki (1989) and Good Clinical Practice (GCP). The department of radiology of the Academic Medical Center of Amsterdam is responsible for the design and conduct of the trial.