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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 9
| Issue : 4 | Page : 288-296 |
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Potential effect of agomelatine versus dexmedetomidine during awake fiberoptic intubation; role of catacholamine
Josef Z Attia, Ahmed Hassanine
Department of Anesthesia and ICU, Faculty of Medicine, Minia University, Minia, Egypt
| Date of Submission | 28-Feb-2022 |
| Date of Decision | 19-May-2022 |
| Date of Acceptance | 03-Jul-2022 |
| Date of Web Publication | 29-Dec-2022 |
Correspondence Address:
PhD Josef Z Attia
Assistant professor of anesthesia and ICU, Faculty of medicine, Minia university, Minia 61111
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/roaic.roaic_13_22
Background Awake fiber-optic intubation is one of the recommended strategies for surgical patients with suspected difficult airway, especially when simultaneous difficult ventilation is anticipated.
Patients and methods In all, 90 patients of both sexes aged between 20 and 55 years, American Society of Anesthesiologist I and II stages were scheduled for elective abdominal surgeries. Patients were randomized into three equal groups. Group A: oral agomelatine at a dose of 10 mg administered with a sip of water 120 min before surgery. Group B: agomelatine+dexmedetomidine. Group C: dexmedetomidine infused at a dose of 1 μg/kg loading infusion per 10 min followed by a continuous infusion of 0.2 μg/kg/h. The following variables (mean arterial pressure, heart rate, oxygen saturation, cough score, postintubation score) and Richmond agitation sedation scale score were recorded in addition to the serum level of norepinephrine.
Conclusion Agomelatine is more effective than dexmedetomidine in making better intubation state with sedation, less desaturation, and hemodynamic stability during awake fiber-optic intubation. Synergestic effect between agomelatine and dexmedetomidine was detected.
Keywords: awake fiber-optic intubation, agomelatine, dexmedetomidine, norepinephrine, stress response
How to cite this article:
Attia JZ, Hassanine A. Potential effect of agomelatine versus dexmedetomidine during awake fiberoptic intubation; role of catacholamine. Res Opin Anesth Intensive Care 2022;9:288-96 |
How to cite this URL:
Attia JZ, Hassanine A. Potential effect of agomelatine versus dexmedetomidine during awake fiberoptic intubation; role of catacholamine. Res Opin Anesth Intensive Care [serial online] 2022 [cited 2023 Mar 26];9:288-96. Available from: http://www.roaic.eg.net/text.asp?2022/9/4/288/365788 |
| Background | |  |
Awake fiber-optic intubation (AFOI) is recommended for patients with predicted difficult airway, retrosternal goiter, and unstable cervical spine injury wherever optimum positioning for laryngoscopy is difficult to achieve. It is necessary to prepare patients before AFOI. Such preparation includes test airway reflexes, adequate sedation, and anxiolysis besides preservation of a patent airway and adequate ventilation. Currently benzodiazepines, opioids, and propofol are used alone or in combination for this purpose [1],[2]. Opioids such as fentanyl and remifentanil are helpful in attenuating hemodynamic response and discomfort during passage of the bronchoscope through the vocal cords. However, all of them are respiratory depressants.
Laryngeal and tracheal sensory receptors are stimulated during tracheal intubation and result in the release of endogenous catecholamines triggering tachycardia and hypertension as a response to sympathetic stimulation. Hence, it is important to take measures to attenuate these pressor responses [3],[4].
Agomelatine is a synthetic naphthalene analog of melatonin with a longer half-life of ∼140 min and higher affinity for these receptors than melatonin. Agomelatine is highly absorbed after oral intake. The peak plasma concentration occurs within 1–2 h. It is the specific agonist of melatonergic (MT)-1 and MT2 receptors and the antagonist of 5HT2C receptors [5]. Consequently, through affecting these receptors, agomelatine reset the disturbed rhythms and sleep–wake rhythms. Impaired sleep has been shown to adversely affect oxidative stress [6], mitochondrial integrity and function as well as inflammation [7], mechanisms that play pathophysiological roles in mood and anxiety disorders. Improvement of sleep by agomelatine can therefore improve oxidative, mitochondrial, and inflammatory processes [8].
Dexmedetomidine is a highly selective α-2-adrenergic receptor agonist that is associated with sedative and analgesic sparing effects, reduced delirium and agitation, perioperative sympatholysis, cardiovascular stabilizing effects, and preservation of respiratory function [9],[10]. It is an ideal agent for conscious sedation, which will ensure spontaneous ventilation with a patent airway, adequate cooperation, smooth intubating conditions, and stable hemodynamics without respiratory depression. These hemodynamic responses would be of little significance in healthy individuals but are detrimental in individuals with limited myocardial reserve due to coronary artery disease, congestive heart failure, hypertension, cardiomyopathy, and in the geriatric age group [11],[12].
Considering these facts, the current study was planned to assess the influence of either melatonin analogs: agomelatine, dexmedetomidine, or its combination in attenuating the hemodynamic reaction, cough score, postintubation score, and the increased level of norepinephrine (NE) that accompanies endotracheal intubation in conscious sedation during AFOI in adult patients scheduled for elective abdominal surgeries.
| Patients and methods | | |
After Institutional Ethics Committee (Institutional Review Broad, Faculty of Medicine, Minia University) (approval no: 37:3/2021) approval this prospective double-blinded, randomized, controlled study was conducted at the Department of Anesthesia and Intensive Care Unit, El-Minia University Hospital. The study involved 90 adult patients of both sexes aged between 20 and 55 years with an American Society of Anesthesiologist (ASA) physical status of I and II, who were scheduled for elective abdominal surgeries. All patients gave written informed consent.
Exclusion criteria included patients with a history of an allergic reaction to any of the used drugs, history of drug or alcohol abuse, abnormal renal or liver function, psychiatric disorders, and any contraindication for nasal intubation like thrombocytopenia or coagulopathies.
We asked the patients to visit the outpatient clinic 1 day before the surgery for assessment and performing laboratory investigations. We also explained to them the study protocols, including analgesic administration. Patients were fasted for 6 h for solid foods and 2 h for water and clear liquids.
| Study design | | |
Patients were allocated by computer-generated random numbers and were divided into three groups.
Group A: oral agomelatine at a dose of 10 mg administered with a sip of water 120 min before surgery [13].
Group B: oral agomelatine at a dose of 10 mg administered with a sip of water 120 min before surgery plus dexmedetomidine infused at a dose of 1 μg/kg loading infusion per 10 min, followed by a continuous infusion of 0.2 μg/kg/h.
Group C: dexmedetomidine infused at a dose of 1 μg/kg of loading infusion per 10 min followed by a continuous infusion of 0.2 μg/kg/h [1].
On arrival to the operating room, standard intraoperative monitoring including heart rate (HR), mean arterial blood pressure (MAP), and oxygen saturation (SpO2) were recorded and subsequent measurements were recorded every 5 min till the end of the operation using a multiparameter monitor (Mindray iMEC12, Nanshan, Shenzhen, China).
In the preoperative room, the study drugs were administered with a sip of water 120 min; before surgery and ECG, pulse oximetry, and noninvasive arterial blood pressure were applied. Vital signs were examined and subsequent values were obtained throughout the operation. Then, an intravenous 18 G cannula was inserted and preloading with Ringer’s solution (10–15 ml/kg) was started. The patients were preoxygenated for 3 min before the induction of balanced anesthesia using an oxygen mask. The patient was nebulized by local anesthesia using 4% lidocaine through a facial mask and intravenous fentanyl injection at 25–50 μg with the studied drugs.
After confirmation of endotracheal tube position, anesthesia was maintained using 100% O2 and isoflurane (1.2–1.5%). Recovery from anesthesia was done by discontinuation of isoflurane and reversal of neuromuscular blockage by atropine 0.01 mg/kg and then neostigmine at 0.03–0.05 mg/kg. After the airway reflexes were regained extubaion was done. Duration of surgery was determined as the time from surgical incision till closure of the wound.
Intubation condition was evaluated by cough score during bronchoscopy as score 1=no cough, 2=slight cough (till two cough), 3=moderate cough (3–5), 4=severe cough (>5 cough) [14]. Tolerance to intubation was evaluated by postintubation score after placement of tube in the trachea as: 1=cooperative, 2=minimal resistance, 3=severe resistance [1].
Level of sedation was evaluated by Ramsay sedation score just after completion of infusion of study drug as 1=anxious, agitated or restless; 2=cooperative, oriented, and tranquil; 3=sedated but responds to command; 4=asleep, brisk glabellar reflex responds to loud noise; 5=asleep, sluggish glabellar reflex, or responds to loud noise; 6=asleep with no response to a painful stimulus [12]. MAP and HR were noted as a baseline and immediately after intubation. SpO2 was monitored throughout the procedure.
Serum norepinephrine level: serum NE level was determined spectroflurophotometrically using a spectrofluorophotometer (Shimadzu RF-5000, Japan). Serum NE level was measured in pg/ml and used as an indicator for hormonal response for endotracheal intubation and preoperative anxiety at the following points.
Statistical analysis
The analysis of the data was performed using the IBM SPSS 20.0 Statistical Package software, Chicago, IL. Data were displayed as mean±SD for quantitative parameters in addition to both number and percentage for categorized data. Analysis of variance was performed for comparison of independent groups for parametric data followed by LSD post-hoc test to assess intergroup differences. Paired sample t test was done to compare parametric quantitative data within each group. χ2 test was carried out to compare categorical variables. A P value of 0.05 or less was set for significance, whereas values 0.01 and 0.001 were considered highly significant.
Sample size calculation
Before the study, the number of patients needed in each group was measured using a power calculation according to data obtained from a pilot study. In each group, a sample size of 30 patients was assigned to achieve 95% power for one-way analysis of variance test at the level of 5% significance using G Power, New York, United States, 3.1.9.2 software.
| Results | | |
Characteristics of patients
No significant changes regarding age, weight, ASA grade, sort of surgery as demonstrated in [Table 1].
Hemodynamic parameters
The baseline mean values for MAP were 86±4.2, 86.7±6.2, and 85.6±6.1 mmHg for groups C, B, and A, respectively, with insignificant differences among the groups. There were two significant rises at Tb and T1 intervened by a significant drop at Ti in MAP from baseline values in between the three study groups, which reached its peak value at T1. On the other hand, the rises in MAP interpreted as the effect of preoperative anxiety and stress response to intubation, respectively, which were significant changes between the three study groups ([Table 2]).
At the third minute after intubation (T3), MAP started to drop significantly through the three study groups. In addition, the MAP continued to drop significantly at 5 min after intubation (T5) in between the three study groups but still higher than the baseline values. Upon reaching the 10th minute after intubation (T10), MAP values became closer to each other with insignificant differences among the three study groups. The changes in MAP values at T3, T5, and T10 could be demonstrated by decrease in stress response to endotracheal intubation. Group B showed the least fluctuation in MAP followed by group A while it was the highest in group C. Changes in MAP values were noted to be similar to changes in values of HR during the same study period ([Table 3]).
T basal: just before medications.
T0: 2 h after medications and just before induction.
Ti: just after induction.
T1: 1 min after intubation.
T3: 3 min after intubation.
T5: 5 min after intubation.
T10: 10 min after intubation
Arterial oxygen saturation
The baseline values of SpO2 were nearly the same in the three groups. No significant differences were observed concerning arterial SpO2, either among the groups or within each group throughout the whole study period ([Table 4]).
Cough score and postintubation score
Cough score less than or equal to 2 was achieved in 29 out of 30 patients in group B, 25 patients in group C, and only in 19 out of 30 patients in group A. However, a cough score more than or equal to 3 was achieved in five out of 30 patients in group C, one patient in group B, and 11 out of 30 patients in group A. The difference was statistically significant (P<0.0001).
Score 1 was found in 21 patients of group C, only 27 in group B, and only 18 patients in group A. This difference was also statistically significant (P<0.0001). ([Table 5]) At the end of study, Richmond agitation sedation scale (RASS) scores of 0 was recorded in all the 90 patients of the study groups at the start of the study (Tb). However, RASS score of +1 was noted in 16, 8, and 1 patient in groups C, A, and B, respectively, 2 h after medications and just before induction (T0) resulting in a clinical significance between the three study groups. Thus, group C showed the highest incidence of anxiety followed by group A, while it was the least in group B ([Table 6]). | Table 6 Changes in Richmond agitation sedation scale in the study groups
Click here to view |
T basal: just before medications.
T0: 2 h after medications.
+1: just before induction.
Serum norepinephrine level
The baseline mean values were 1.47±0.04, 1.46±0.05, and 1.48±0.07 pg/ml for groups A, B, and C, respectively, with no significant difference among the groups. A significant rise in serum NE level from baseline values was observed 2 h after administration of medications and just before induction (Ti), which continued to rise significantly 1 min after intubation (T1) in between the three study groups till reaching its peak value at T1. At the fifth minute after intubation (T5), serum NE level was dropped significantly through the three study groups. Group B showed the least fluctuation in serum NE level followed by group A, while it was still high in group C as shown in [Figure 1]. | Figure 1 Changes in serum NE level (pg/ml) in the study groups. NE, norepinephrine.
Click here to view |
T basal: just before medications.
T0: 2 h after medications and just before induction.
T1: 1 min after intubation.
T5: 5 min after intubation.
| Discussion | | |
AFOI frequently requires sedation, anxiolysis, and relief of discomfort without impairing ventilation and depressing cardiovascular function. The goal is to allow the patient to be responsive and cooperative. Various drugs are used for providing favorable intubation conditions during AFOI [15]. However, most of them, such as fentanyl, remifentanil, midazolam, and propofol that have been reported to assist AFOI cause respiratory depression, cardiovascular adverse effects, and airway obstruction leading to hypoxemia [16]. In this study, we try to compare the effect of either the effect of dexmedetomidine or agomelatine versus its combination on the hemodynamic status and postintubation cough score besides the serum level of NE.
Dexmedetomidine induces sedation involving activation of endogenous sleep-promoting pathway through the postsynaptic α-2 receptors in the locus ceruleus, which modulates wakefulness. The major advantages of dexmedetomidine infusion during AFOI are a unique form of sedation where patients remain sleepy, but are easily aroused, cooperative with minimum respiratory impairment. The feasibility of dexmedetomidine has been recently studied either as a sole sedative agent or as an adjuvant during AFOI [17].
Physiological roles of melatonin include sleep induction and maintenance [5], anti-inflammatory, immunological effects, and antioxidative effect [18]. Melatonin has a mild hypotensive effect and the mechanism of action on the circulation is complex and unclear. Melatonin may bind to specific melatonin receptors in the blood vessels, interfering with the vascular response to catecholamines. Perioperatively, melatonin has potential uses like decreasing the blood pressure, neuroprotective role, and improving surgical outcomes [19]. Considering these facts, the current study was planned to examine the effects of melatonin analog; agomelatine in attenuating hemodynamic responses to awake endotracheal intubation in patients and in turn reducing the complication that may occur.
A study was done to compare the role of either oral agomelatine at a dose of 10 mg 2 h before the induction of anesthesia or dexmedetomidine at a dose of 2 μg/kg versus patients who received agomelatine plus dexmedetomidine, in attenuating the pressor response during AFOI. Agomelatine, as melatonin agonists, has been approved by the FDA for long-term use for the treatment of insomnia. The advantage of melatonin analogs is their good safety profile because of specificity for two principal melatonin receptors: MT1 and MT2 [20]. Agomelatine is well absorbed after oral administration, has longer half-life 120 min and affinity for these receptors more than melatonin. Agomelatine is used to assess hemodynamic response for laryngoscopy and intubation in ASA I and II adult patients undergoing elective surgeries under general anesthesia [21]. Dexmedetomidine has also been proved as an effective agent for AFOI in certain difficult airway scenarios [22],[23],[24]. Bergese et al. [25] noted that dexmedetomidine at 1 μg/kg bolus was safe and beneficial for patients undergoing AFOI even without airway nerve block or topical anesthesia.
There was no significant difference between the groups in view of their age, sex, and weight; mean time of intubation; and duration of surgery. In fact, increases in HR and blood pressure are among the signs used to detect the inadequate depth of anesthesia by anesthesiologists.
In the agomelatine group, the change in blood pressure may be due to the anxiolytic and sedative effect of agomelatine. These changes at different intervals after premedication correlate well with the decrease in anxiety scores and the increase in sedation scores after the premedication [26].
In the current study, changes in MAP and HR values were noted to be similar to each other during the study period. The previous parameters showed a significant rise from the baseline values 2 h after the medications and just before the intubation (T0), which corresponds to the time of preoperative anxiety. Then, a significant drop occurred just after induction and before intubation (Ti) in the three study groups, which was explained by the cardiovascular depressive effect of anesthesia induction with no significant difference among the study groups.
Other significant rises in the parameters from the baseline values at first (T1), third (T3), and fifth (T5) minute after intubation were recorded with the highest value at T1 and the least value at T5 and that correspond with the time of stress response to endotracheal intubation. A significant variance among the three groups at T0, T1, T3, and T5 was observed. The lowest values were found in the agomelatine group plus dexmedetomidine followed by the agomelatine group, while the highest was in the dexmedetomidine. Change in serum NE level values confirmed the previously mentioned changes in MAP, HR, and RASS score as there was a significant rise in serum NE level from baseline values 2 hs after administration of medications and just before induction (Ti), which continued to rise significantly 1 min after intubation (T1).
That is explained by the effect of preoperative anxiety and stress response to intubation. At the fifth minute after intubation (T5), serum NE level dropped significantly through the three study groups due to of the decrease in stress response to endotracheal intubation. Group B showed the least fluctuation in serum NE level followed by group A, while it was the highest in group C.
In addition, several studies have reported the changes in plasma catcholamine (noradrenaline, adrenaline, and dopamine) levels during endotracheal intubation. The most significant findings were the increases in arterial pressure and plasma noradrenaline concentration after intubation. The elevation of the blood pressure was considerable and paralleled the increases in plasma noradrenaline concentration [27].
Capuzzo et al. [28] performed a prospective, double-blinded, and randomized study to compare the effects of melatonin and placebo in diminishing preoperative anxiety in elderly patients less than 65 years with ASA physical status I–III using a numerical rating scale (range, 0–10). The patients were randomized to the two groups, the placebo group included 71 patients and the melatonin group received 10 mg melatonin and included 67 patients. They showed that melatonin did not significantly decrease anxiety and depression in comparison to placebo. Their different results could be attributed to different populations (age, sex, and sort of surgery) or methodologies.
Chu et al. [29] observed better tolerance to intubation without respiratory depression and upper airway obstruction in the dexmedetomidine group; furthermore, Bergese et al. [25] noted that dexmedetomidine at 1 μg/kg bolus was safe and beneficial for patients undergoing AFOI even without airway nerve block or topical anesthesia.
In addition, dexmedetomidine produced better intubating conditions than fentanyl used at a dose of 2 μg/kg. Dexmedetomidine has also been proved to be an effective agent for AFOI in certain difficult airway scenarios [23].
Won et al. [30] compared remifentanil with dexmedetomidine for conscious sedation during bronchoscopy. They found that there were no significant difference of sedation level, MAP, HR, and patient satisfaction score (P>0.05) but cough score and incidence of desaturation were significantly lower (P<0.01) in the dexmedetomidine group than the remifentanil group.
In this study, blood pressure and HR monitoring were used to evaluate the influence of study drugs on the pressor response to laryngoscopy and intubation, and also RASS for preoperative sedation assessment and serum level of NE as an indicator for hormonal response were assessed.
In addition, several studies have reported the changes in plasma catcholamine (noradrenaline, adrenaline, and dopamine) levels during endotracheal intubation. The most significant findings were the increases in arterial pressure and plasma noradrenaline concentration after intubation. The elevation of the blood pressure was considerable and paralleled the increases in plasma noradrenaline concentration [27].
Therefore, the difference in HR and blood pressure at the different time intervals of the study compared with the baseline value would be an indication of a patient’s level of anxiety, with higher levels being related to higher degrees of anxiety. The mean basal HR on the day before surgery were comparable between the three groups (P=0.97). Intergroup comparison shows statistically significant (P<0.001) difference in the HR measured on the day of surgery at 1, 3, 5, and 7 min intervals. HR was statistically insignificant on the day before surgery at 0, 1, 10, 15 min as the P value is more than 0.05. [Table 2] shows the MAP between the three groups. The MAP values were not comparable between the groups on the day before surgery, before premedication, and at 0 1, 3, 5, 7, 10, and 15 min after premedication (P>0.5). There was statistically insignificant difference (P>0.05 in MAP on the day before surgery, on the day of surgery 0, 1, 3, 5, 7, 10, and 15 min after medication). In the agomelatine group, the decrease in blood pressures from baseline was seen at 15 min and the maximum decrease was at 60 min. The change may be due to the anxiolyic and sedative effect of agomelatine. These changes at different intervals after premedication correlates well with the decrease in anxiety scores and increase in sedation scores after premedication.Dexmedetomidine infusion may cause bradycardia, atrial fibrillation, hypotension, or hypertension particularly in higher doses [31]. However, there are reports of unaltered hemodynamics even in higher doses of dexmedetomidine infusion [32]. Yavascaoglu et al. [33] reported that dexmedetomidine prevented the hemodynamic response to tracheal intubation more effectively than esmolol.
| Conclusion | | |
We conclude that agomelatine in combination with dexmedetomidine are more effective than either agomelatine or dexmedetomidine alone during AFOI, as it provides better intubation condition, hemodynamic stability, and adequate sedation without desaturation.
Ethics approval, guidelines, and consent to participate: The written informed consent was obtained from patients. The study approval and all experiments were performed in accordance with relevant guidelines and regulations of Faculty of Medicine, Minia University, Research Ethics Committee (FMREC).
Acknowledgements
The authors thank all members of Anesthesia and ICU, Faculty of Medicine, Minia University, Egypt.
Authors’ contributions: all authors read and approved the final manuscript. J.Z.A. performed the study design and conduction, data collection and analysis, preparation of the manuscript, and writing up of the first draft. J.Z.A and A.H. performed the study design and conduction, data collection and analysis, and revising the manuscript.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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