Role of melatonin in attenuation of haemodynamic responses to laryngoscopy and intubation

Effects of oral melatonin premedication on hemodynamic responses to intubation, anesthetic requirements and postoperative sedation: A randomized trial

Background and Aims

Sedative effects of melatonin may have an additive effect on general anesthesia (GA). We compared hemodynamic response to intubation following oral premedication with melatonin versus placebo. Induction dose of propofol, isoflurane and fentanyl consumption were also compared.

Material and Methods

This prospective, double-blinded study was conducted in fifty patients randomized into two equal groups. Group M received oral melatonin 6 mg and group P a placebo two hours before surgery. All patients were induced with intravenous propofol of 1.5-2.5mg/kg till loss of response to verbal commands, three minutes after vecuronium, laryngoscopy was done and trachea was intubated. Heart rate (HR) and mean arterial pressures (MAP) were recorded before premedication, before induction, immediately after induction and then at 1,3,5 and 10 minutes after intubation.

Results

Mean HR was comparable in both groups throughout the study period. Group M had significantly lower MAP before induction and immediately after induction (P < 0.05). At all other time points MAP remained comparable in both groups. Mean isoflurane consumption was significantly lower in group M compared to group P (14.8 ± 4.2 vs 19.7 ± 3.2 mL). Propofol requirement for induction was also significantly lower in group M (102.4 ± 19.6 vs 122.4 ± 26.3mg). Intraoperative fentanyl consumption was comparable.

Conclusion

Oral premedication with melatonin 6mg administered two hours before surgery significantly reduced MAP before and after induction of GA with a significant reduction in dose of propofol requirement. Titrating induction dose of propofol till loss of response to verbal commands did not effectively attenuate responses to laryngoscopy and intubation following melatonin oral premedication.

Evidence for the Benefits of Melatonin in Cardiovascular Disease

The pineal gland is a neuroendocrine gland which produces melatonin, a neuroendocrine hormone with critical physiological roles in the circadian rhythm and sleep-wake cycle. Melatonin has been shown to possess anti-oxidant activity and neuroprotective properties. Numerous studies have shown that melatonin has significant functions in cardiovascular disease, and may have anti-aging properties. The ability of melatonin to decrease primary hypertension needs to be more extensively evaluated. Melatonin has shown significant benefits in reducing cardiac pathology, and preventing the death of cardiac muscle in response to ischemia-reperfusion in rodent species. Moreover, melatonin may also prevent the hypertrophy of the heart muscle under some circumstances, which in turn would lessen the development of heart failure. Several currently used conventional drugs show cardiotoxicity as an adverse effect. Recent rodent studies have shown that melatonin acts as an anti-oxidant and is effective in suppressing heart damage mediated by pharmacologic drugs. Therefore, melatonin has been shown to have cardioprotective activity in multiple animal and human studies. Herein, we summarize the most established benefits of melatonin in the cardiovascular system with a focus on the molecular mechanisms of action.

Role of melatonin in attenuation of hemodynamic response to intubation and anesthetic requirements: a randomized, controlled, double-blind study

BACKGROUND

Melatonin has been studied to have anxiolytic, sedative, and analgesic effects. However, there is limited data on the effect of melatonin in the attenuation of hemodynamic response to intubation. We aimed to study whether preanesthetic oral melatonin attenuates hemodynamic responses to intubation and anesthetic requirements.

METHODS

Sixty-four patients scheduled for laparoscopic cholecystectomy were randomized into melatonin or placebo group (n = 32 each). Melatonin group received two tablets (3 mg each) of melatonin, and the placebo group received two tablets of vitamin D3 120 min before induction. Hemodynamic parameters were recorded during induction and postintubation for 15 minutes. Total induction dose of propofol, total intraoperative fentanyl consumption, and adverse effects of melatonin were also noted.

RESULTS

Postintubation rise in heart rate (HR) was less in the melatonin group compared to the placebo group (10.59% vs. 37.08% at 1 min, respectively) (p < 0.0001). Maximum percentage increase in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) was lesser in melatonin group than placebo group (SBP 9.25% vs. 37.73%, DBP 10.58% vs. 35.51%, MBP 9.99% vs. 36.45% at 1 min postintubation. respectively) (p < 0.0001). Induction dose of propofol (1.42 mg.kg^-1 vs. 2.01 mg.kg^-1) and the number of patients requiring additional fentanyl intraoperatively (3 vs. 11) were also significantly reduced in the melatonin group.

CONCLUSION

Premedication with 6 mg of oral melatonin resulted in significant attenuation of postintubation rise in HR, SBP, DBP, and MBP. It also reduced the induction dose of propofol, total intraoperative fentanyl consumption without any adverse effects.

Predicting Gag, Discomfort, and Laryngeal Visualization in Patients Undergoing Flexible Laryngoscopy with Stroboscopy

OBJECTIVE

To investigate potential associations between the Predictive Gagging Survey (PGS) with patient experience of gag and discomfort as well as provider perception of patient gag and level of laryngeal visualization during flexible laryngoscopy with stroboscopy (FL-S).

METHODS

A total of 53 adult patients undergoing FL-S were recruited for this prospective non-controlled study. PGS was completed before FL-S. Patients rated perceived level of gag and discomfort on a 10-point severity scale after FL-S. Additionally, providers completed a Gagging Severity Index (GSI) reflecting their impression of patient gag and level of laryngeal visualization following FL-S. Spearman rank correlation coefficients were used to assess associations.

RESULTS

There was a positive association with PGS score and patient perception of gagging (0.34; P = .013) and patient perception of discomfort (0.38; P = .005). No significant association was found between PGS score and provider GSI (-0.12; P = .39) or level of laryngeal visualization (0.15; P = .29). A negative association was found between level of laryngeal visualization and patient perception of gagging (-0.34; P = .012) and discomfort (-0.44; P = .001). No significant differences were found between current and former smokers compared to never smokers for GSI or patient-perceived gag or discomfort.

CONCLUSIONS

While not predictive of GSI or level of laryngeal visualization, the PGS was found to be a useful tool in predicting patient experience of gagging and discomfort during FL-S, further reinforcing the subjective experience of this procedure. Use of the PGS may be helpful in identifying specific candidates who may struggle with subjective discomfort or gagging during FL-S for future studies considering interventions to manage and meaningfully decrease discomfort. Having such an instrument is important given the low number of individuals who struggle with discomfort during the exam.

Melatonin Exerts Anti-Inflammatory, Antioxidant, and Neuromodulatory Effects That Could Potentially Be Useful in the Treatment of Vertigo

The acute phase of vertigo involves multiple neurotransmitters, inflammatory mediators, and products of oxidative stress. The vestibular pathway has multiple melatonin receptors distributed along its path, both centrally and peripherally. In addition, melatonin has been shown to be a powerful antioxidant and anti-inflammatory agent against factors related to vertigo, such as Bax/caspases, interleukins, and chemokines. Likewise, it exerts central GABAergic, antidopaminergic, and anti-migraine functions and regulates sympathetic activity in a similar way to the drugs classically used in acute vestibular crisis. In this review, the role of melatonin as a potential treatment of the acute phase of vertigo is discussed.

Comparative evaluation of oral melatonin and oral clonidine for the attenuation of haemodynamic response to laryngoscopy and tracheal intubation-A prospective randomised double blind study

BACKGROUND AND AIMS

Laryngoscopy and endotracheal intubation cause significant derangement of the haemodynamic parameters proving detrimental for some patients. Clonidine, an α-2 adrenoreceptor agonist, and melatonin, the pineal hormone, have been used for the attenuation of these haemodynamic responses. This study was designed to evaluate the effect of oral melatonin and clonidine in attenuating the haemodynamic responses to laryngoscopy and intubation.

MATERIALS AND METHODS

In this prospective randomised double-blind study, 60 American Society of Anaesthesiologists (ASA) grade I and II patients aged 20-60 years of either gender scheduled to undergo elective surgery under general anaesthesia were randomly divided into Group M and Group C and orally received 6 mg of melatonin and 0.2 mg of clonidine, respectively, 120 min before the induction of anaesthesia. The haemodynamic parameters-heart rate (HR), systolic blood pressure, diastolic blood pressure, mean arterial pressure and rate -pressure product(RPP) were recorded before and 120 min after the administration of the study drug, before induction, immediately after intubation and at 1, 3, 5 and 10 min following intubation. Sedation was assessed using the Ramsay Sedation Scale. The qualitative and quantitative variables were analysed using Chi square test and unpaired student t test, respectively. For intragroup comparison of quantitative data, paired t test was applied. A P value <0.05 was considered as statistically significant.

RESULTS

A significant difference was noted between the groups regarding HR and RPP 0, 1, 3 and 5 min after intubation. The Ramsay sedation score ranged between 2 and 3 at all time intervals.

CONCLUSION

Although both the drugs are effective, oral melatonin proved superior to oral clonidine in attenuating the haemodynamic response to laryngoscopy and tracheal intubation without any side effects.

Comparison of Effects of Oral Melatonin with Oral Alprazolam used as a Premedicant in Adult Patients Undergoing Various Surgical Procedures under General Anesthesia: A Prospective Randomized Placebo-Controlled Study

BACKGROUND AND AIMS

Preoperative anxiety is a major concern in patients undergoing any surgical procedure. Various drugs have been used to alleviate it. This study aims to compare the effects of oral melatonin versus oral alprazolam on preoperative anxiety, sedation, orientation, and cognitive function.

MATERIALS AND METHODS

A total of 90 adult patients were randomly allocated into three groups. Group M (n = 30) received oral melatonin 3 mg (2 tablets); Group A (n = 30) received oral alprazolam 0.25 mg (2 tablets), and Group P (n = 30) received placebo, multivitamin tablet (2 tablets) as premedication. The objectives of our study were to compare anxiety, sedation, orientation, and cognitive function using visual analog scale (VAS) anxiety score, Ramsay Sedation Score (RSS), orientation score, and Digit symbol substitution test (DSST) score before and after 120 min of giving premedication. For statistical analysis, paired t-test, Chi-square test, analysis of variance, and post hoc bonferroni test were used.

RESULTS

Mean VAS scores for anxiety (after 120 min) were significantly reduced in Group M (3.9 ± 1.53) and Group A (4.43 ± 1.67) when compared to Group P (4.73 ± 0.82) (P < 0.05). RSS was higher in Group A as compared to Group M and Group P (P < 0.05). No significant difference in orientation score was observed in all the three groups before and after premedication (P > 0.05). DSST score (cognitive function) was better in Group M when compared to both Group A and Group P (P < 0.05).

CONCLUSION

Oral melatonin (6 mg) when used as a premedicant is an effective alternative to alprazolam regarding providing better anxiolysis, lesser sedation along with maintenance of cognitive, and psychomotor function.