|Year : 2021 | Volume
| Issue : 1 | Page : 13-22
Effect of palatable lidocaine gel versus dexmedetomidine on gag reflex during propofol-based sedation for patients undergoing elective upper gastrointestinal endoscopy: a randomized controlled study
Shereen E Abd Ellatif, Marwa M Medhat
Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Zagazig University, Zagazig, Egypt
|Date of Submission||09-Jun-2020|
|Date of Decision||14-Nov-2020|
|Date of Acceptance||30-Oct-2020|
|Date of Web Publication||31-Mar-2021|
MD Shereen E Abd Ellatif
Anesthesia Department, Faculty of Medicine, Zagazig University, Zagazig, 44511
Source of Support: None, Conflict of Interest: None
Background and objective Upper gastrointestinal tract endoscopy (UGIE) is widely performed under propofol sedation, which is considered as a safe sedation agent and alleviates the sympathetic response to the procedure. However, retching and gag reflex still disturb ∼29% of those patients despite being under propofol sedation.
Patients and methods A total of 120 adult patients scheduled for elective UGIE were randomly allocated into three equal groups (40 patients each): group C was given propofol 50 mg, group D was given propofol 50 mg+dexmedetomidine 0.5 μg/kg, and group L was given propofol 50 mg+15 g palatable lidocaine gel. The outcome measures included incidence of gag reflex, propofol consumption, recovery time, intraoperative hemodynamics, and patients’ and endoscopist’s satisfaction.
Results The incidence of gag reflex was statistically significantly reduced in groups L and D compared with group C; however, the reduction was more in group L but with no significant difference when compared with group D group. Propofol consumption was statistically significantly lower in groups L and D compared with group C, as well as recovery time was significantly shorter in groups L and D compared with group C. Group L showed the least hemodynamic changes among the three groups, and the endoscopist as well as the patients were statistically significant more satisfied in both groups L and D when compared with group C.
Conclusion Using palatable lidocaine gel in addition to propofol in patients undergoing UGIE was safe and effectively reduced the incidence of gag reflex and the dose of intravenous propofol with its subsequent complications, shortening recovery time and improving patient and endoscopist satisfaction.
Trial registration This clinical trial was registered with ClinicalTrials.gov (NCT04213833).
Keywords: dexmedetomidine, gag reflex, palatable lidocaine gel, propofol, sedation, upper gastrointestinal tract endoscopy
|How to cite this article:|
Abd Ellatif SE, Medhat MM. Effect of palatable lidocaine gel versus dexmedetomidine on gag reflex during propofol-based sedation for patients undergoing elective upper gastrointestinal endoscopy: a randomized controlled study. Res Opin Anesth Intensive Care 2021;8:13-22
|How to cite this URL:|
Abd Ellatif SE, Medhat MM. Effect of palatable lidocaine gel versus dexmedetomidine on gag reflex during propofol-based sedation for patients undergoing elective upper gastrointestinal endoscopy: a randomized controlled study. Res Opin Anesth Intensive Care [serial online] 2021 [cited 2021 May 18];8:13-22. Available from: http://www.roaic.eg.net/text.asp?2021/8/1/13/312581
| Introduction|| |
Upper gastrointestinal tract endoscopy (UGIE) is a valuable procedure that is commonly used for the diagnosis of possible causes of upper gastrointestinal tract symptoms such as bleeding, pain, dysphagia, recurrent vomiting, and reflux. Moreover, it is a safe and easy procedure for taking biopsy sample for suspected esophageal, gastric, and duodenal diseases, grading, and even ligating varices ,.
UGIE is commonly performed under propofol sedation, which is considered a safe sedation technique and attenuates the sympathetic response to the procedure. However, retching and gag reflex still disturb ∼29% of those patients despite being under propofol sedation and may affect the safety of the procedure, patient’s tolerance, and endoscopist’s satisfaction . Any further trial to minimize gagging and overcome such undesirable adverse effects through deepening sedation may compromise hemodynamics and cause respiratory depression. These complications add to the overall costs as it increases morbidity and duration of patients’ hospitalization .
Dexmedetomidine is a short-acting selective α2‑agonist sedoanalgesic drug that has been used frequently in many diagnostic and therapeutic procedures . It has unique sedative activity not present in the other conventional sedative drugs, so it is unlikely to cause the restlessness or respiratory depression seen with GABA receptor agonists such as propofol. Therefore, it alleviates the associated physical and emotional distress and enhances successful completion of the procedure without remarkable gag reflex . However, many clinicians may have qualms regarding the safety profile of giving dexmedetomidine in such endoscopic procedures owing to its well-known hemodynamic adverse effects (especially bradycardia and hypotension) .
Topical pharyngeal anesthesia (TPA) has been evolved to suppress gag reflex during UGIE that is elicited by touching any part of the five trigger zones, which include base of the tongue, palate uvula, palatoglossal, palatopharyngeal folds, and posterior pharyngeal wall, leading to contraction of the pharyngeal constrictors muscles. Therefore, the application of TPA to the aforementioned areas would be able to attenuate or even ablate gagging thus increasing the patient’s comfort and tolerance to the procedure, and decreasing the dose of intravenous (i.v.) anesthetics, adjuvant, and their potential complications; accordingly, TPA is preferred and used in many centers, especially for diagnostic endoscopy ,.
Lidocaine is widely used for TPA, and there are many forms of it such as the lozenge, gel, spray, and inhaler that are commercially available ,.
Palatable lidocaine gel is a local anesthetic hindering the ionic fluxes that initiate and propagate impulses and thereby it stabilizes the neuronal membrane and enhances its local anesthetic action. It is considered safe, well-tolerated, and quite promising TPA particularly in elderly patients and in patients with comorbidities in office-based endoscopy .
The aim of this study was to compare the effect of topical palatable lidocaine gel versus i.v. dexmedetomidine as an adjuvant to propofol-based sedation on the incidence of gag reflex and total propofol consumption during UGIE.
| Patients and methods|| |
This prospective randomized double-blind controlled study was conducted in Zagazig University Hospitals from January 2020 to June 2020. Approval of Institutional Review Board and the patient’s informed written consent were obtained. Our clinical study was registered with ClinicalTrials.gov (NCT042138).
Adult patients aged 18–60 years old, of either sex, American Society of Anesthesiologists (ASA) I or ASA II were scheduled for elective UGIE. Patients with clinically significant cardiovascular, respiratory diseases (as obstructive sleep apnea, severe chronic obstructive pulmonary disease, or asthma), psychiatric disease, and history of allergy to any of the study drugs were excluded from this study.
Sample size calculation
The sample size was calculated to be 120 cases divided into three groups, with 40 in each group, calculated using open Epi program. At confidence interval 95% and power of test 80%, the percentage of gag reflex in dexmedetomidine group was 36.7 versus 70% in propofol group .
The patients enrolled in this study were randomly allocated into three equal groups (40 of each) by a computer-generated randomization table: group C, where patients were given propofol 50 mg; group D, where patients were given propofol 50 mg+dexmedetomidine 0.5 μg/kg; and group L, where patients were given propofol 50 mg+15 g palatable lidocaine gel. The study was a prospective double-blinded study (patients and the endoscopist were totally blinded to the randomization).
All participating patients visited during their preprocedure preparation to discuss the goal and end points of the study, clarify the advantages and possible adverse effects of the strategy, and provide an informed written consent regarding the procedure. On physical examination, special attention was directed to document airway assessment, vital signs, cardiac and chest condition, and exclude contraindications. All patients were investigated by complete blood count, coagulation profile, blood sugar levels, liver, and kidney function tests. Patients were kept nil per oral for 6–8 h before the procedure.
An i.v. access was secured. The baseline values of heart rate (HR), oxygen saturation (SpO2), and mean arterial blood pressure (MAP) were recorded.
Patients of group C were sedated with 50-mg propofol (10 mg/ml) given slowly i.v. over 1 min, whereas those of group D were sedated with 0.5 μg/kg dexmedetomidine i.v. followed by syringe containing 50 mg propofol (10 mg/ml) given slowly i.v. over 1 min.
For group L, 15 g of palatable lidocaine gel 2% (15 g pack Oracure oral gel; Amoun Pharmaceutical Co., Cairo, Egypt) was gently applied 3–5 min before the endoscopy at three consecutive 30-s intervals on the palate and the peritonsillar areas, and the patients were informed to spread it within their mouth with their tongue and thereafter swallow it to cover the oropharynx and esophagus. Patients were asked to register the onset of numbness, and then patients were given a syringe containing 50 mg propofol (10 mg/ml) slowly i.v. over 1 min as sedation.
Immediately following injection of propofol in each group, sedation was assessed by light glabellar tap or loud noise to maintain score more than four according to Ramsay sedation score, as shown in [Table 1] , and if further top-up doses of propofol were needed to reach the target score, increments of 20 mg propofol were given. The sedation level was assessed every 2–3 min and supplemental oxygen was maintained for all patients via nasal cannula and oxygen flow of 4 l/min. A mouthpiece was placed, and the endoscope (Pentax video processor, Pentax EPK-i5000; HOYA, Tokyo, Japan) was well lubricated before the introduction.
- Gag reflex (primary outcome) was assessed as ‘present or not’ when vomiting-like response was provoked upon the introduction of the endoscope.
- Secondary outcomes:
- Intraprocedure hemodynamics (HR and MAP) and SpO2 were recorded every 2 min for the first 10 min, and then every 5 min till the end of the procedure. If HR was less than 50 beats/min or a 20% decrease from the baseline value, it was labeled as bradycardia, and 0.02 mg/kg atropine was given. Moreover, hypotension was considered when MAP dropped below 60 mmHg or a 20% decrease from the baseline value and treated with a bolus dose of 5 mg ephedrine. Oxygen desaturation was defined as a drop of SpO2 level below 92% for more than 10 s and treated with airway assistance and maintained oxygen supplement.
- Total intraprocedural incremental doses of propofol were given to each patient.
- Procedure time.
- Recovery time was recorded from the end of the procedure and removal of the endoscope and every 5 min thereafter until Ramsay sedation score 2 was reached.
- Patient’s satisfaction regarding discomfort (gagging and pain) was assessed using a numerical rating scale from 1 to 10 (1=satisfied and tolerated well the procedure to 10=unsatisfied) ,.
- Endoscopist’s satisfaction regarding gagging and difficulty of performing the procedure was assessed using a numerical rating scale from 1 to 10 (1=no gagging/difficulty to 10=maximum gagging/difficulty) ,.
- Adverse effects, such as the incidence of apnea, airway obstruction with subsequent need for airway assistance, and emergence delirium where the patient was disoriented or talking irrelevantly upon recovery, were recorded.
The collected data were statistically analyzed using Statistical Package for Social Science software (version 20, SPSS Inc., Chicago, Illinois, USA). Continuous variables with a normal distribution were reported as mean±SD. Categorical variables were summarized as number and percentages. Quantitative data were evaluated using analysis of variance followed by post-hoc test when significant, whereas qualitative data were evaluated by χ2 or Fisher’s exact test when appropriate. P values less than 0.05 and less than 0.001 were considered statistically significant and highly statistically significant, respectively.
| Results|| |
A total of 120 patients scheduled for elective upper gastrointestinal tract endoscopy were assessed for eligibility to participate in this study and randomized into three equal groups of 40 each, as shown in the CONSORT flow diagram ([Figure 1]).
There was no statistically significant difference (P>0.05) among the studied groups regarding age, sex, ASA physical status (I/II), BMI, and procedure time, ensuring homogeneity of groups ([Table 2]).
|Table 2 Patients’ characteristics and procedure time of the studied groups|
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The MAP was comparable at baseline reading in groups C, D, and L, and immediately after starting the procedure later on, MAP decreased at 2, 4, 6, 8, 10, and 15 min compared with the baseline value (0 min) within each group. When comparing group C with the other two interventional groups, there was a statistically significant decrease in mean values of MAP in group C (P<0.05) throughout the procedure; however, a statistically insignificant decrease in mean value of MAP was noticed in group D compared with group L ([Figure 2]).
|Figure 2 Intraprocedure changes in the mean arterial pressure (MAP) among the studied groups (error bars represent SE). Group C=propofol, group D=propofol+dexmedetomidine, group L=palatable lidocaine gel+propofol.|
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The HR was comparable at baseline reading in groups C, D, and L, and at immediately after starting the procedure later on, there was a statistically insignificant decrease of HR at 2, 4, 6, 8, 10, and 15 min compared with the baseline value (0 min) within each group; moreover, on comparing among the three studied groups, there was a statistically insignificant decrease of HR in groups C and D compared with group L (P>0.05) ([Figure 3]).
|Figure 3 Intraprocedure heart rate (HR) changes among the studied groups (error bars represent SE). Group C=propofol, group D=propofol+dexmedetomidine, group L=palatable lidocaine gel+propofol.|
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The SpO2 was comparable at baseline reading in groups C, D, and L, and immediately after starting the procedure later on, there was a statistically insignificant decrease of SpO2 at 2, 4, 6, 8, 10, and 15 min compared with the baseline value (0 min) within each group, as well as on comparing between the three studied groups (P>0.05) ([Figure 4]).
|Figure 4 Intraprocedure oxygen saturation (SpO2) changes among the studied groups (error bars represent SE). Group C=propofol, group D=propofol+dexamedetomidine, group L=palatable lidocaine gel+propofol.|
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There was a statistically significant increase in the incidence of gag reflex (P<0.05) in group C when compared with group D and group L, with no significant difference on comparing between the last two groups. Moreover, there was a highly statistically significant increase in the total dose of propofol consumption during the whole procedure (P<0.001) in group C when compared with the other two groups, with no significant difference on comparing between these two groups. Recovery time was highly statistically significantly shorter in groups D and L (P<0.001) when compared with group C, with no significant difference in comparing between D and L groups themselves ([Table 3]).
|Table 3 Procedure data and periprocedure complications of the studied groups|
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For the incidence of intraprocedural airway obstruction and apnea, both were statistical significantly more (P<0.011 and 0.001, respectively) in group C when compared with groups D and L, with no statistically significant difference (P>0.05) on comparing between groups D and L; however, the incidence of hypotension, bradycardia, and emergence delirium showed no statistically significant difference (P>0.05) among the three studied groups ([Table 3]).
There was a highly statistically significant improvement of both patient and endoscopist’s satisfaction (P<0.001) in groups D and L when compared with group C, with no statistically significant difference (P>0.05) between the former groups (D and L) ([Table 4]).
|Table 4 Patient’s and endoscopist’s satisfaction among the studied groups|
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| Discussion|| |
UGIE is a day-case procedure, where patient safety and comfort can be compromised while the endoscope is still within the esophagus by gag reflex. The gag reflex is provoked owing to the stimulation of the oropharynx by the endoscope and thus may reduce the ease of the procedure and may get worse and cause trauma to the patient .
Propofol is the most common i.v. anesthetic used for sedation and analgesia during this procedure; however, its usage may be associated with adverse effects such as respiratory depression, hypotension, and apnea .
Dexmedetomidine is a relatively newer sedative drug as compared with other anesthetics. It is a short-term medication that provides hypnosis, amnesia, anxiolysis, and analgesia; however, it may be associated with adverse hemodynamic effects such as bradycardia and hypotension .
TPA using lidocaine with i.v. sedation has been studied in several trials showing that it increases patient comfort and endoscopist’s satisfaction and tolerability to endoscopic introduction ,.
In our study, we tried to evaluate the role of palatable lidocaine gel and i.v. dexmedetomidine as an adjuvant to propofol sedation in UGIE on the incidence of occurrence of gag reflex and total propofol consumption during the procedure.
Topical lidocaine spray is conventionally used with i.v. anesthetics before endoscopy, yet it is not preferred by most patients as it has a sour taste and is irritant. Other forms of TPA were used including an inhaler, lollipop, lozenges, viscous agents, and conventional gel (with a very bad taste); however, some of them carry a risk of retching and vomiting ,, so we preferred the use of palatable gel, as it allows the application of a dense and sticky layer of lidocaine to the five trigger areas of gag reflex to provide a more reliable and tolerable topical anesthesia during the procedure compared with spray and other forms.
Our results revealed that there was a statistically significant reduction in the incidence of occurrence of gag reflex in palatable lidocaine gel and dexmedetomidine groups compared with the control group; however, the incidence of gag reflex decreased more in lidocaine gel but with no significant difference when compared with dexmedetomidine group. Thus, it was reflected in the form of a significant increase in tolerability to procedure and patients’ satisfaction as well as increased endoscopist satisfaction in both palatable lidocaine gel and dexmedetomidine groups compared with the control group.
This is in line with an earlier study done by Ghallab et al. , involving patients undergoing diagnostic esophagogastroduodenoscopy allocated into two groups; propofol group and palatable lidocaine gel together with i.v. propofol group. They concluded that lidocaine gel with propofol decreased incidence of gagging more significant than propofol alone and improved patient comfort and endoscopist satisfaction . Another study performed by Soweid et al.  concluded that posterior lingual lidocaine swab effectively suppressed gagging and significantly increased patient tolerance and endoscopist satisfaction during UGIE when compared with lidocaine spray. In another randomized trial done by Heuss et al. , propofol alone was compared with propofol combined with TPA for UGIE, and they reported that TPA reduced gagging more; however, the patient discomfort and the ease of the procedure were similar in both groups.
In accordance with our results, Abbas et al.  allocated patients into three equal groups; propofol group, propofol+ketamine group, and propofol+dexmedetomidine group. They found that propofol+dexmedetomidine reduced the incidence of gag reflex during UGIE better than ketamine with propofol. Moreover, a study done by Samson et al.  concluded that endoscopist satisfaction was significantly more in patients receiving dexmedetomidine compared with midazolam or propofol, owing to decrease in gag reflex and rate of movement during the endoscopy. In contrast, patient satisfaction was significantly more in those receiving midazolam, and this could be explained due to amnestic property of midazolam as patients were interviewed within 1 h of completion of the procedure . In another study done by Sethi et al. , where patients were undergoing endoscopic retrograde cholangiopancreatography, the authors noted a higher endoscopist and patient satisfaction and the procedure elicited less gagging in dexmedetomidine group compared to midazolam group.
In our study, the total dose of propofol consumption during the procedure was statistically significantly lower in palatable lidocaine gel and dexmedetomidine groups when compared with the propofol group, with no statistically significant difference between dexmedetomidine and palatable lidocaine gel group. From the aforementioned, it is clear that it is reflected on the recovery time which was significantly shorter in dexmedetomidine and palatable lidocaine gel group compared with the propofol group and thus definitely leads to decrease hospital stay and costs.
These results were matched with Ghallab et al. , as they found that the dose of propofol was markedly less in palatable lidocaine gel to the extent that one patient did not receive the induction dose of propofol and the whole procedure was performed with lidocaine gel only without any discomfort or gagging during the procedure; moreover, recovery time was shorter in palatable lidocaine gel compared with propofol group. Similarly, several studies by Soma et al. , Ayoub et al. , and Soweid et al.  revealed that the application of posterior pharyngeal lidocaine either lollipop, gel, spray or swab decreased the need of i.v. sedation.
Again, in agreement with our findings, Abbas et al.  reported that propofol doses were significantly lower in dexmedetomidine with propofol group than the propofol group and even than propofol with ketamine group also. For recovery time, it was shorter in dexmedetomidine and ketamine groups than in propofol group only. Moreover, Samson et al.  mentioned in their study that patients in dexmedetomidine group consumed lower but statistically insignificant doses of fentanyl, had higher sedation level, and had significantly faster recovery compared with midazolam and propofol groups, and this was also in line with those noticed by Vazquez‑Reta et al.  and Takimoto et al. .
Our study reported hemodynamic changes and SpO2 during the procedure. It was noticed that MAP, HR, and SpO2 were comparable at baseline reading in the three studied groups and immediately after starting the procedure, and then their values decreased at 2, 4, 6, 8, 10, and 15 min from the baseline, but statistically significant fall in MAP with no significant fall in both HR and SpO2 were seen in propofol group when compared with the other two groups; this may be owing to the higher doses of propofol consumed in the propofol group, which may induce transit hypotension and apnea, leading to transit fall in MAP and SpO2, respectively. It is also worth mentioning that occurrence of hypotension and bradycardia was comparable in the three studied groups, with no statistically significant difference; however, both were reported more but not significant in dexmedetomidine group when compared with palatable lidocaine gel group. So, it was clear that palatable lidocaine gel group associated with less hemodynamic changes regarding (MAP and HR) among the three groups, and this could be one of the merits of its usage.
This was in agreement with Samson et al. , who found that propofol group had a significant decrease in MAP at various instances to the extent that seven patients developed hypotensive episodes and were treated with fluid boluses during the procedure; however, there was no statistically intergroup variability for other vital parameters (RR, HR, and SpO2).
These results did not agree with Ghallab et al. , as there was no significant difference regarding hemodynamics between palatable lidocaine and propofol group, but on the contrary, SpO2 level showed better values in palatable lidocaine gel group. Moreover, Muller et al.  did not match our results, as they recorded that dexmedetomidine was not as effective as propofol with fentanyl for maintaining conscious sedation during endoscopic retrograde cholangiopancreatography; furthermore, it caused hemodynamic instability in the form of a greater decrease in the blood pressure and HR. This may be owing to higher doses of dexmedetomidine, as it was used alone for sedation without any rescue drug, especially with the prolonged procedure time in their study compared with our study (24 vs. 14 min, respectively), in addition to the inclusion of patients of ASA III, which may aggravate response to the drug.
Speaking about the adverse effects, our results reported that incidence of apnea and airway obstruction were statistically significantly more in propofol group when compared with the other two groups; this may be owing to the greater doses of the propofol consumed in the propofol group, with no statistically significant difference on comparing between dexmedetomidine and palatable lidocaine gel group. However, the occurrence of emergence delirium showed no statistically significant difference among the three studied groups. This is compatible with Ghallab et al. , who recorded that the incidence of apnea was significantly more in propofol group compared with palatable lidocaine gel group. Moreover, Abbas et al.  found that the incidence of postprocedure delirium and airway assistance were comparable, with no significant difference among the three studied groups.
Although the evaluation of the costs incurred were missed in the study, which could be an important issue for comparison among our studied groups, it seems that the usage of palatable lidocaine gel has lower costs compared with dexmedetomidine cost, which is relatively an expensive drug. Moreover, it decreased propofol consumption and its dependent complications. In addition, it reduced recovery time, and this may influence subsequent hospital stay, so all these factors appeared to lower the overall costs.
There are some limitations in our study such as the small sample size, which included stable ASA I and ASA II patients; therefore, our findings cannot be generalized to all patients, especially those with other comorbidities to ensure hemodynamic stability of palatable lidocaine gel in such patients. Moreover, we did not consider the anxiety level and young-aged patients, which may influence on the tolerability of the procedure. In our study, relatively short endoscopic procedures were involved; however, lengthy procedures may be associated with more discomfort and retching. Therefore, future studies may be recommended to study such variable agents.
| Conclusion|| |
The use of palatable lidocaine gel in addition to propofol in patients undergoing UGIE was safe and effectively reduced the incidence of gag reflex and the dose of i.v. propofol with its subsequent complications; therefore, this may help patients to return to their daily activity immediately after the procedure and thus may decrease the overall cost of the procedure. Moreover, palatable lidocaine gel was as effective as dexmedetomidine during the procedure; thus, it can replace dexmedetomidine and avoid its possible hemodynamic complications (hypotension and bradycardia). Therefore, this may be a very promising modality to be enhanced, especially in elderly patients with comorbidities and in office-based UGIE.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]