DOI: https://doi.org/10.21203/rs.3.rs-1976991/v1
Propofol-balanced sedation is widely used in endoscopic retrograde cholangiopancreatography (ERCP) procedures, but sedation-related adverse events (SRAEs) commonly occur. The combination of dexmedetomidine with opioids and benzodiazepines has provided effective sedation with a superlative degree of safety during different clinical scenarios. The aim of this study was to compare sedation efficacy and safety between dexmedetomidine and propofol with a balanced administration of opioids and benzodiazepines during ERCP procedures.
Forty-one patients were randomly divided into two groups, the dexmedetomidine (DEX) group and the propofol (PRO) group. As premedication, all participants received an intravenous bolus dose of 0.02 mg•kg− 1 midazolam and 0.2 µg•kg− 1 sufentanil. Patients in the DEX group received an additional bolus of 0.6 µg•kg− 1 dexmedetomidine over 2 min followed by a dexmedetomidine infusion at 1.2 µg•kg− 1•h− 1, whereas the PRO group received a 1–2 mg•kg− 1 propofol bolus over 30 s followed by a propofol infusion at 2–3 mg•kg− 1•h− 1. The primary outcome was the incidence of hypoxemia (SpO2 < 90% for > 10 s) during ERCP.
All patients achieved the targeted sedation level with the Ramsay Sedation Scale ≥ 4. When compared with the PRO group, the incidence of hypoxemia was significantly reduced in the DEX group. Respiratory depression (respiratory rate of < 10 bpm•min− 1) was more frequently observed among PRO patients than DEX patients. During procedures, endoscopists’ and patients’ satisfaction scores were comparable between groups, as were patients’ pain and amnesia scores.
Dexmedetomidine provided satisfactory sedation safety with no downstream effects on sedation efficacy when performing ERCP in comparison with propofol in combination with opioids and benzodiazepines.
Chinese Clinical Trial Registry- ChiCTR2200061468. Date of registration: 25/6/2022.
Endoscopic retrograde cholangiopancreatography (ERCP) is a complex procedure commonly used for diagnostic or therapeutic purposes in pancreaticobiliary pathologies, with the patient in a prone or semi-prone position. Sedation and anesthesia are usually required to relieve patient anxiety and discomfort, improve examination outcomes, and diminish the patients’ memory of the event. It is noteworthy that anesthesia care standards for ERCP have not been established and sedation practice patterns vary substantially worldwide [1].
Many sedative medications, with different anesthetic mechanisms, are used to provide appropriate sedation and anesthesia levels for ERCP. Historically, ERCP was performed under moderate sedation using opioids and benzodiazepines, with or without adjunctive agents; however, moderate sedation was largely abandoned due to insufficiency leading to premature completion [2, 3]. Propofol or dexmedetomidine as adjuncts to moderate sedation have been considered in recent decades [4, 5]. Propofol is used for painless endoscopy due to its rapid onset of action and short half-life; however, it causes cardiovascular inhibition and dose-dependent respiratory depression, thereby necessitating constant supervision by appropriately trained anesthesia professionals [6, 7]. Moreover, the prone or semi-prone position during ERCP may be associated with altered cardiopulmonary physiology and limited airway access [8]. Therefore, airway management may be further complicated and difficult in worst-case scenarios under propofol sedation.
Dexmedetomidine is a highly selective α-2-adrenoceptor agonist and provides analgesia and sedation with minimal cardiopulmonary compromise at clinically deep sedation levels. Recently, several investigations showed dexmedetomidine exerted synergistic effects in combination with opioids and benzodiazepines, and provided adequate procedural sedation similar to propofol in different clinical scenarios [9–11]. However, dexmedetomidine may cause bradycardia and sympathetic inhibition [12]. While both sedatives have their advantages and disadvantages, to the best of our knowledge, no agreement has been achieved on the best sedation regimen to facilitate ERCP procedures in an effective, safe, and satisfying manner.
When considering previous evidence on dexmedetomidine efficacy and safety, we hypothesized that the drug combined with opioids and benzodiazepines could reduce the incidence of cardiopulmonary adverse events concomitant with equally satisfactory sedation conditions for the endoscopist and patient during ERCP procedures, when compared with sedation by propofol. Furthermore, midazolam is the first choice of benzodiazepine for fast acting, reversible, and retrograde amnesia effects. Sufentanil has high potency and affinity to the opioid receptor, with weak respiratory depression. Hence, combined sufentanil and midazolam administration was used as the basic ERCP medication throughout our study.
We designed this study to compare sedation efficacy and safety between dexmedetomidine and propofol with balanced sufentanil and midazolam administration during ERCP procedures.
This study was approved by the Medical Ethics Committee of the First Affiliated Hospital of Wenzhou Medical University and was registered in the Clinical Trial Registration Center of China (ChiCTR2200061468). The study adhered to the World Medical Association Declaration of Helsinki. The data have been furnished in accordance with the Consolidated Standards of Reporting Trials (CONSORT) statement. This article has been presented in accordance with the CONSORT reporting checklist. Patients scheduled for an ERCP procedure between June 2022 and August 2022 were eligible to be enrolled in this prospective, randomized, single-blind study if they were aged between 18 to 80 years and had American Society of Anesthesiologists (ASA) physical status I–III. Exclusion criteria: ASA physical status IV–V, refusal to participate, pregnant or breast-feeding patients, allergy history to the study medication, and long-term sedative or narcotic analgesic drug abuse. Written informed consent was obtained from all patients.
Patients fasted for at least 6 h before ERCP. After intravenous access was obtained, an infusion of 500 mL Ringer’s solution was started at a rate of 250 mL•h− 1. Patients were placed in a semi-prone position and 2 L•min− 1 oxygen was given through a nasal cannula. Patients received laryngopharynx topical anesthesia with 2% lidocaine, an intravenous dose of 0.2 µg•kg− 1 sufentanil and 0.02 mg•kg− 1 midazolam as premedication. Additionally, the DEX group received an initial bolus of 0.6 µg•kg− 1 dexmedetomidine over 2 min followed by a dexmedetomidine infusion at 1.2 µg•kg− 1•h− 1. The PRO group received an initial bolus of 1–2 mg•kg− 1 propofol over 30 s followed by a propofol infusion at 2–3 mg•kg− 1•h− 1. We targeted a sedation level with the Ramsay Sedation Scale (RSS, Table 1) ≥ 4. In case of RSS < 4 or intolerance of the procedure, 0.1 µg•kg− 1 sufentanil and 0.01 mg•kg− 1 midazolam were used as rescue drugs. The procedure was performed by an experienced endoscopist with at least 300 ERCPs/year.
| Sedation score | Response |
|---|---|
| 1 | Anxious and agitated or restless, or both |
| 2 | Co-operative, oriented, and tranquil |
| 3 | Responding to commands only |
| 4 | Brisk response to light glabellar tap or loud auditory stimulus |
| 5 | Sluggish response to light glabellar tap or loud auditory stimulus |
| 6 | No response to stimulus |
Baseline demographic data including age, gender, and body mass index were measured preoperatively. The sedation level was assessed using RSS for clinical scoring and the bispectral index (BIS) as an objective tool. During the procedure, heart rate (HR), oxygen saturation (SpO2), respiratory rate (RR), mean blood pressure (MAP), RSS, and BIS levels were monitored and recorded at the following time points: 5 min before sedation (baseline, T0), 5 min after sedation (T1), 0, 5, 10, 15, 20 min after starting ERCP (T2–T6), and post-procedure 0, 5, 10 min (T7–T9). After the procedure, patients were observed in the recovery unit for at least 30 min. Recovery status was assessed using the modified Aldrete Score [13]. Patients were ready for discharge when this score was at least 9 without substantial side effects such as nausea and dizziness.
After signing informed consent sheets, patients were randomized at a 1:1 ratio into DEX group or PRO group according to a computer-generated randomization table. Sealed envelopes were given to each patient as they reported for the procedure. An experienced anesthesiologist administered drugs and an anesthesia resident collected clinical data. Both the endoscopist and anesthesia resident were blinded to the study drugs, but the anesthesiologist was informed because the drugs were visibly distinguishable.
Time to achieve RSS ≥ 4 was recorded as onset time of targeted sedation. Recovery time was measured from the end of ERCP to achievement of a modified Aldrete Score of 9. Rescue drug injections were recorded. Immediately after the procedure, endoscopists were asked to rate their satisfaction: 1) satisfied, 2) mild dissatisfied, 3) severe dissatisfied, and 4) unbearable. On the day after the procedure, the satisfaction score, pain and amnesia of the patients were evaluated by an anesthesia resident as followings: satisfaction: 1) comfortable, 2) mild discomfort, 3) severe discomfort, and 4) unbearable). Pain: 1) no pain, 2) mild pain, 3) moderate pain, and 4) severe pain. Amnesia: 1) I do not remember any part of the procedure, 2) I remember some parts of the procedure, and 3) I completely remember the procedure.
Hemodynamic and respiratory variables including MAP, HR, SpO2, and RR were compared between groups in terms of sedation regimen safety. Perioperative adverse events included sedation-related adverse events (SRAEs) and ERCP-related adverse events. SRAEs were defined as hypoxemia (SpO2 < 90% for > 10 s), respiratory depression (RR < 10 bpm), hypotension (MAP < 65 mmHg), and bradycardia (HR < 40 beats•min− 1). If respiratory depression or oxygen desaturation was observed, supplemental oxygen was administered via the nasopharyngeal airway. Hypotension or bradycardia was treated with intravenous saline or vasoactive agents (ephedrine or atropine). ERCP-related adverse events were defined as the presence of post-ERCP pancreatitis (PEP), bleeding, perforation, and infection. Severe adverse events were defined as the requirement of tracheal intubation and/or mechanical ventilation.
The primary outcome was the incidence of hypoxemia. The secondary outcomes were as follow: (1) onset time of targeted sedation, recovery time, and rescue drug injections; (2) the degree of endoscopists’ and patients’ satisfaction, and patients’ pain and amnesia scores; (3) RSS, BIS, MAP, HR, SpO2, and RR at T0–T9; (4) the adverse events recorded, which included respiratory depression, hypotension, bradycardia, and ERCP-related adverse events.
We hypothesized that sedation with dexmedetomidine for ERCP would reduce the incidence of hypoxemia by at least 50% when compared with sedation with propofol. Based on a previous study by Jokelainen et al. [14], 60.7% of patients had hypoxemia episodes with propofol-based sedation for ERCP. To achieve a power ≥ 0.80 and an α level = 0.05, the sample required for chi-squared with Fisher’s exact test was 17 patients per group. Assuming a 10% dropout rate, the final sample size was set at 19 patients per group.
Statistical analyses were conducted using SPSS software version 26.0 (IBM, Armonk, NY, USA). An independent sample t test and nonparametric tests were used for continuous variables. For categorical variables, Pearson’s chi-squared and Fisher’s exact tests were applied for variables that expressed as numbers and/or percentages of the total. For normal distributions, continuous variables were represented as the mean ± standard deviation. Non-normally distributed data were compared using Kolmogorov-Smirnov tests and data were presented as the median and inter-quartile range (IQR). A P value < 0.05 was considered statistically significant.
In our Gastrointestinal Endoscopy Unit, 44 eligible patients scheduled for an ERCP procedure were randomized to 22 patients per group. Two patients from the DEX group and one from the PRO group were excluded due to failed duodenal intubation. Therefore, data were finally collected from 20 and 21 patients in DEX and PRO groups, respectively, as showed in the Consort flow diagram (Fig. 1).
Patient characteristics and ERCP procedure details are shown in Table 2. The mean patient age was 57 years in the DEX group and 61 in the PRO group. Patients in both groups were comparable in terms of physical characteristics and underlying comorbidities. Furthermore, no significant differences were identified between groups in terms of indications for ERCP and the mean procedure duration (P > 0.05).
|
DEX Group (n = 20) |
PRO Group (n = 21) |
p value |
|
|---|---|---|---|
|
Age (y) |
57.1 ± 16.1 |
61.0 ± 12.8 |
0.395 |
|
Sex (male/female, n) |
9/11 |
9/12 |
0.890 |
|
BMI (kg/m2) |
23.2 ± 2.6 |
22.7 ± 3.6 |
0.676 |
|
Cigarette smoking [n (%)] |
4 (20.0) |
1 (4.8) |
0.311 |
|
Alcohol intake [n (%)] |
3 (15.0) |
5 (23.8) |
0.477 |
|
Comorbidities [n (%)] |
|||
|
Cardiovascular disease |
6 (30.0) |
9 (42.9) |
0.393 |
|
Respiratory disease |
None |
4 (19.0) |
0.126 |
|
Diabetes |
3 (15.0) |
5 (23.8) |
0.751 |
|
Renal disease |
6 (30.0) |
2 (9.5) |
0.208 |
|
Liver disease |
7 (35.0) |
12 (57.1) |
0.155 |
|
ASA status (I/II/III, n) |
4/10/6 |
2/16/3 |
0.284 |
|
ERCP indications [n (%)] |
0.798 |
||
|
Common bile duct stone |
17 (85.0) |
16 (76.2) |
|
|
Biliary strictures |
None |
2 (9.5) |
|
|
Gallbladder carcinoma |
1 (5.0) |
None |
|
|
Pancreatic pathology |
1 (5.0) |
2 (9.5) |
|
|
Other |
1 (5.0) |
1 (4.8) |
|
|
Duration of procedures (min) |
23.3 ± 11.5 |
25.5 ± 14.7 |
0.593 |
|
Table legends: Normally distributed data are presented as mean ± SD, which were analyzed using an independent sample t test; categorical variables are presented as count (%), which were analyzed using the Pearson’s chi-squared test and Fisher’s exact test Abbreviations: ERCP endoscopic retrograde cholangiopancreatography, DEX dexmedetomidine, PRO propofol, BMI body mass index, ASA American Society of Anesthesiologists, SD standard deviation |
|||
As indicated in Fig. 2, RSS and BIS scores were comparable at baselines and no differences were observed at T2–T9 time points; however, the RSS score was significantly higher while the BIS score was lower in the PRO group than those in the DEX group at T1 time point (P < 0.05).
Sedation efficacy parameters are shown in Table 3. A faster onset of targeted sedation was observed in the PRO group when compared with the DEX group. In contrast, patients in the DEX group had decreased duration required for recovery when compared with those in the PRO group (P < 0.05). The requirements of administering rescue agents to facilitate procedures were similar between groups (P > 0.05).
|
DEX Group (n = 20) |
PRO Group (n = 21) |
p value |
|
|---|---|---|---|
|
Onset time of targeted sedation (min) |
2.7 ± 1.8 |
1.0 ± 0.0 |
0.000 |
|
Recovery time (min) |
1.6 ± 1.9 |
6.9 ± 3.2 |
0.002 |
|
Rescue drug injections [n (%)] |
5 (25.0) |
4 (19.0) |
0.934 |
|
Table legends: Normally distributed data are presented as mean ± SD, which were analyzed using an independent sample t test; categorical variables are presented as count (%), which were analyzed using the Pearson’s chi-squared test and Fisher’s exact test Abbreviations: DEX dexmedetomidine, PRO propofol, SD standard deviation |
|||
The degree of endoscopists’ and patients’ satisfaction, and patients’ pain and amnesia scores were recorded (Fig. 3). Endoscopists’ and patients’ satisfaction scores were comparable between groups, while no differences were identified between groups in terms of patients’ pain and amnesia (P > 0.05).
As shown in Fig. 4, no significant between-group differences were observed for baseline variables of MAP, HR, SpO2, and RR at T0. Patients in the DEX group exhibited a statistically significant higher MAP after the loading dose injection at T1 while patients exhibited a lower MAP at T9 when compared with PRO patients (P < 0.05). A statistical difference in HR was identified in both groups from 5 min after the initiation of sedation to procedure end. There was no difference in SpO2 between groups throughout the procedure (P > 0.05), however, RR in the PRO group was significantly lower than the DEX group at T1 and T2 (P < 0.05).
SRAEs are indicated in Table 4. Significant differences in the incidence of hypoxemia and respiratory depression were found between groups (P < 0.05). Six patients in the PRO group and none of patients in the DEX group had hypoxemia episodes. Respiratory depression occurred in 81% of patients in the PRO group and 35% of patients in the DEX group (P < 0.05). No statistical differences were observed between groups in terms of hypotension and bradycardia episodes (P > 0.05).
|
DEX Group (n = 20) |
PRO Group (n = 21) |
p value |
|
|---|---|---|---|
|
Hypoxemia [n (%)] |
None |
6 (28.6) |
0.032 |
|
Respiratory depression [n (%)] |
7 (35.0) |
17 (81.0) |
0.003 |
|
Hypotension [n (%)] |
5 (25.0) |
7 (33.3) |
0.558 |
|
Bradycardia [n (%)] |
4 (20.0) |
1 (4.8) |
0.186 |
|
Table legends: Categorical variables are presented as count (%), which were analyzed using the Pearson’s chi-squared test and Fisher’s exact test Abbreviations: DEX dexmedetomidine, PRO propofol |
|||
ERCP-related adverse events are shown in Table 5, with no differences observed between groups. No severe adverse events occurred in either group.
|
DEX Group (n = 20) |
PRO Group (n = 21) |
p value |
|
|---|---|---|---|
|
PEP [n (%)] |
5 (25.0) |
4 (19.1) |
0.934 |
|
Bleeding [n (%)] |
None |
1 (4.8) |
> 0.999 |
|
Perforation [n (%)] |
None |
None |
1.000 |
|
Infection [n (%)] |
6 (30.0) |
4 (19.1) |
0.651 |
|
Table legends: Categorical variables are presented as count (%), which were analyzed using the Pearson’s chi-squared test and Fisher’s exact test Abbreviations: ERCP Endoscopic retrograde cholangiopancreatography, PEP Post-endoscopic retrograde cholangiopancreatography pancreatitis, DEX dexmedetomidine, PRO propofol |
|||
In this study, our data showed that a dexmedetomidine-based sedation regimen provided a superlative degree of safety, with minimal respiratory inhibition during ERCP with no downstream effects on procedural efficacy when compared with propofol sedation.
ERCP is an essential diagnostic and therapeutic method for biliary and pancreatic diseases, generally conducted under anesthesia due to its painful and time-consuming properties. Sedation without intubation administered by an anesthesiologist appears to be the most recommended strategy for ERCP due to a reduced incidence of adverse discharge [15]. Propofol is the mainstay sedative for sedation without intubation during gastrointestinal endoscopy for its outstanding characters of potent action, rapid onset, and fast recovery [16]. However, doubts concerning its sedation-related side effects hinders its widespread clinical application, particularly during ERCP for elderly populations and those requiring prone positions. Indeed, previous studies reported a high incidence of hypotension (4.8–19%) and hypoxemia or apnea (3.3–60.7%) under propofol sedation during ERCP [6, 14, 17, 18]. Dexmedetomidine is a highly selective α-2-adrenoceptor agonist with sedative, analgesic, and anxiolytic properties. Balanced dexmedetomidine administration with opioids and benzodiazepine could be an alternative and safer method to propofol during advanced endoscopic procedures. However, to our knowledge, the data are limited on the sedation efficacy and safety of dexmedetomidine combined with opioids and benzodiazepine administration when compared with propofol during ERCP.
Several controlled randomized trials investigated the sedation efficacy of dexmedetomidine combined with opioids and benzodiazepines during ERCP procedures [4, 19]. Lu et al. [4] demonstrated that 95% of patients completed ERCP without discomfort and additional sedative-use under dexmedetomidine and remifentanil anesthesia. Ikeda and colleagues [19] showed that combination treatments with dexmedetomidine and benzodiazepines provided high-quality sedative effects with rare excessive movement. Consistent with previous results, all patients in our study achieved the targeted RSS sedation level, and completed the procedure without premature termination. Moreover, RSS sedation levels and BIS scores were similar between groups after bolus administration with no significant differences in the requirement of rescue agents.
A previous meta-analysis reported that propofol provided a higher level of satisfaction when compared with dexmedetomidine in patients undergoing gastrointestinal endoscopy [20], while another meta-analysis demonstrated a higher satisfaction of endoscopic performers were rated for dexmedetomidine-based sedation when compared with propofol [21]. In the present study, we demonstrated comparable satisfaction levels among endoscopic performers and patients when different anesthetic agents were used. Such a discrepancy may be attributed to the synergistic effects of opioids and benzodiazepines when added to dexmedetomidine sedation [10]. Additionally, the effect of suppressing gastric motility with dexmedetomidine-based sedation may contributed to the improved endoscopist satisfaction when compared with propofol [11]. Above all, our study showed that both sedating regimens provided equivalent sedation efficacy with relatively satisfactory levels of sedation.
It was worth noting that sedation depth was transiently deeper at T1 in the PRO group compared to the DEX group. This was due to the rapid onset of propofol activity, which was further verified by the shorter onset time of targeted sedation in the PRO group compared to the DEX group. In terms of shorter onset times, this may be a double-edged sword for sedation. As shown in Fig. 4, MAP and RR were significantly lower in the PRO group at T1. This finding reflected the narrow therapeutic index of propofol and the risk of cardiovascular complications especially during the induction period. This indicated a difficulty in controlling cardiorespiratory stability with propofol, especially in the elderly, by an unexperienced anesthesiologist or under nurse-guided sedation [22]. In contrast, patients in the DEX group had a faster recovery than the PRO group due to the unusual property of its arousable sedation [10]. Patients in the DEX group were aroused immediately by name calling or a shake stimulus after ERCP. Additionally, dexmedetomidine enabled patients to achieve an Aldrete score of 9 at procedure end, and to leave the operation room within 2 min.
Respiratory and cardiovascular suppress are well-known as the side effects of propofol. The features that differentiate dexmedetomidine from propofol are the maintenance of spontaneous breathing and the avoidance of profound cardiovascular compromise during sedation. In our study, MAP was lower after induction but higher during the recovery period under propofol sedation when compared with dexmedetomidine. The short elimination half-life of propofol may be responsible for these differences, in contrast, dexmedetomidine has a relatively slow elimination with cumulative effects leading to a prolonged cardiovascular depression [23]. Consequently, dexmedetomidine and propofol may have similar hypotension risks which may occur throughout the procedure. Dose-dependent respiratory depression is another major concern for propofol treatment [6]. In our study, airway manipulation due to transient hypoxemia was required in 29% of patients, while 81% of cases exhibited a respiratory rate < 10 bpm in the PRO group. Though no different effects on SpO2 were observed between the two segments, fluctuations in values were obvious under propofol sedation. These results agreed with Yang et al. [24] who showed that 28% of patients experienced hypoxemia during propofol sedation. For dexmedetomidine, its major issue is bradycardia resulting from α 2-adrenoceptor activation, and we observed a lower heart rate in the DEX group throughout the study, which could be immediately reversed by the treatment with atropine.
In recent years, several case reports suggested an association between short-term exposure to propofol and acute pancreatitis [25, 26], therefore propofol sedation has raised additional concerns for increasing PEP risks. Our ERCP procedure lasted for 25 min on average and our results showed that such a short-term exposure to propofol exhibited similar risk than application of dexmedetomidine in terms of PEP, consistent with Li et al. [27]. Furthermore, previous investigations indicated that dexmedetomidine may provide superior anti-inflammatory effects and decrease infection risks [28]. However, no significant differences in the incidence of post-ERCP infections were observed between groups. Based on these data, propofol or dexmedetomidine sedation are comparatively safe anesthetics strategy for ERCP without increasing additional risks of ERCP-related adverse events.
The standard recommendation for dexmedetomidine administration method is somewhat complicated, as the loading dose should be given over 10 min followed by an infusion rate of 0.7–1.4 µg•kg− 1•h− 1[12]. However, data from previous studies demonstrated that 0.5 µg•kg− 1 dexmedetomidine could be used as a bolus within 30 s in patients, without causing any substantial hemodynamic compromise [18, 29]. Therefore, a 0.6 µg•kg− 1 loading dose of dexmedetomidine over 2 min, alternating with sufentanil and midazolam, were used in our study.
Our study had several limitations. (1) The endoscopist was assumed to be blinded to group assignment, but it was still uncertain whether they could identify sedative agents in terms of physical property differences between dexmedetomidine and propofol. Therefore, we could not completely eliminate the personal bias when they answered questionnaires. (2) Our study included patients with ASA status I–III and < 80 years old in a single center. Older age and an ASA status of III or higher were demonstrated to be independent predictors of developing SRAEs under propofol sedation [24]. Additionally, the beneficial effects of dexmedetomidine-based sedation may have been more apparent in critically ill patients, this factor may have skewed our results.
Both dexmedetomidine and propofol-based sedating regimens exhibited satisfactory sedative efficacy for ERCP. Dexmedetomidine, in combination with opioids and benzodiazepines, offered distinct advantages in sedation safety due to a lower incidence of respiratory adverse events during ERCP when compared with propofol. Therefore, dexmedetomidine could be an ideal substitute to propofol for patients undergoing ERCP.
ERCP: endoscopic retrograde cholangiopancreatography; SRAEs: sedation-related adverse events; ASA: American Society of Anesthesiologists; RSS: Ramsay Sedation Scale; BIS: bispectral index; HR: heart rate; SpO2: oxygen saturation; RR: respiratory rate; MAP: mean blood pressure; PEP: post-ERCP pancreatitis; IQR: inter-quartile range.
Acknowledgements
Not applicable.
Authors’ contributions
WZ performed the study and wrote the manuscript; LW contributed to critical revision of the manuscript; NZ was responsible for statistical analysis; WW helped collecting data; HL was responsible for the concept and design the study as well as the interpretation of the data. All the authors read and approved the final manuscript.
Funding
This study was not funded by any external or internal funding.
Availability of data and materials
The datasets are available from the corresponding author on reasonable request.
Ethics approval and consent to participate
This trial was approved by the Medical Ethics Committee of the First Affiliated Hospital of Wenzhou Medical University and all patients provided written informed consent. All methods were performed in accordance with the relevant guidelines and regulations.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.