Official Journals By StatPerson Publication
Table of Content - Volume 11 Issue 1 -July 2019
Attenuation of haemodynamic response to laryngoscopy and endotracheal intubation: A comparative study between fentanyl and esmolol
Rajiv Aggarwal1, Manjula Sudhakar Rao2*, Alok Basu Roy3, Ravindra Kumar Arora4
1Consultant, Department of Anesthesiology, Regency Hospital, Kanpur, INDIA. 2Senior Resident, Department of Anesthesiology, Father Mullers Medical College Hospital, Kankanady, Mangalore, Karnataka, INDIA. 3,4Senior Consultant, Department of Anesthesiology, Max Superspeciality Hospital, Vaishali, Ghaziabad, Uttar Pradesh, INDIA. Email: manjularao1010@gmail.com
Abstract Background: Laryngoscopy and endotracheal intubation have become the integral part of general anaesthesia and critical care of patients. It has been practiced since its description by Rowbothom and Magill in 1921. These are noxious stimuli which provoke a transient but marked sympathetic response manifesting as hypertension and tachycardia, more severe in hypertensive patients. Materials and methods: This prospective study was conducted in the Department of Anaesthesiology, Max Hospital Vaishali Gaziabad during the period of 12 months from December 2014 to December 2015. A total of 100 normotensive patients between 18 and 60 years of age with ASA grade 1 and 2 risk, undergoing elective surgical procedures under general anaesthesia were included. Patients undergoing emergency surgical procedures, anaesthesia with non-invasive airway devices haemodynamically unstable patients, patients on beta blockers and calcium channel blockers and patients with difficult airway were excluded. Results: In the fentanyl group, the average heart rate increased by 1.85 bpm during laryngoscopy and intubation. In the esmolol group, the rise in heart rate was 3.1bpm which is higher than that of fentanyl group. The increase in heart rate in the esmolol group as a response to intubation was statistically significant. Hence our study showed that Fentanyl is a better drug to control the tachycardia as a response to laryngoscopy and intubation. Both fentanyl and esmolol effectively prevented rise of SBP as a response to intubation. Conclusion: 1Fentanyl is better than esmolol in controlling tachycardia in response to laryngoscopy and endotracheal intubation. 2Both fentanyl and esmolol are effective in controlling the rise in SBP as a response to laryngoscopy and endotracheal intubation. 3Esmolol is more effective than fentanyl in controlling SBP and RPP. In conclusion, both fentanyl and esmolol are effective in attenuation of hemodynamic response to laryngoscopy and intubation. Fentanyl is more effective in preventing tachycardia while esmolol is more effective in controlling rise in systolic blood pressure and rate pressure product. Key Word: haemodynamic.
INTRODUCTION Laryngoscopy and endotracheal intubation have become the integral part of general anaesthesia and critical care of patients. It has been practiced since its description by Rowbothom and Magill in 1921.1 Laryngoscopy and tracheal intubation are noxious stimuli which provoke a transient but marked sympathetic response manifesting as hypertension and tachycardia.2 Hypertensive patients are more prone to have significant increase in blood pressure (BP), whether they have been treated beforehand or not.3 In susceptible patients, particularly those with systemic hypertension, coronary artery disease, cerebrovascular disease and intracranial aneurysm, even these transient changes can result in potentially deleterious effects like left ventricular failure, arrhythmias, myocardial ischaemia, cerebral haemorrhage and rupture of cerebral aneurysm.3,4 Many pharmacological methods have been devised to reduce the extent of these haemodynamic events. These include opioids, local anaesthestics, beta adrenergic blockers and vasodilator drugs. Beta adrenergic blockers have been used to successfully attenuate this undesirable response to intubation. They act by blocking the effect of the hyperactive sympathetic system on the cardiovascular system. A short acting and cardio selective blocker may be more useful with minimal adverse effects.5 Esmolol is an ultra-short acting, β1 cardio selective, β blocking agent with a short half-life (9min). This agent has been used to reduce the increase in heart rate and blood pressure in response to tracheal intubation, thereby reducing the myocardial oxygen demand.6 Fentanyl is a synthetic opioid agonist used as an adjuvant to provide analgesia during general anaesthesia. Studies have shown its efficacy in reducing the hemodynamic response to laryngoscopy and endotracheal intubation. It acts by blunting the tracheal sensitivity to the stimulus of laryngoscopy and intubation.7 In this study we have compared the efficacy of Esmolol and Fentanyl in attenuating the pressor response to laryngoscopy and intubation during general anaesthesia.
AIMS AND OBJECTIVES
MATERIALS AND METHODS This prospective randomised single blind comparative study was conducted in the department of anaesthesiology, Pushpanjali Crosslay Hospital Ghaziabad during the period of 12 months from December 2014 to December 2015. A total of 100 patients who underwent elective surgical procedures under general anaesthesia were randomly enrolled for this study using table of random numbers. Inclusion criteria
Exclusion criteria
METHODOLOGY Sample size- Sample size was calculated using the following formula
Zα = 1.96 at 95% confidence level Zβ = 1.28 at 90% power. σ and d are combined SD and mean difference from reference no 35 Hence the sample size was calculated as 98. 100 patients who met the defined inclusion and exclusion criteria were enrolled for this study. A written informed consent was taken from the patients who were enrolled. Block randomisation method was used to assign patients into two groups- Group A (Fentanyl group) and Group B (Esmolol group). A number was assigned to each patient of the day using random number chart. Patient with even number was taken into esmolol group and the one with odd number was taken into fentanyl group, thus avoiding selection bias. Patients were evaluated by taking detailed history, physical examination, airway assessment and relevant investigations preoperatively. They were asked to fast overnight. Group A patients received Inj. Fentanyl 1.5 microgram per kg intravenously 5 minutes prior to laryngoscopy. Group B patients received Inj. Esmolol 2 milligram per kg intravenously 3 minutes prior to laryngoscopy. All patients received standard premedications like H2 blockers, prokinetics, antisialogogues and anxiolytics prior to induction. They were pre-oxygenated and induced with Inj.Propofol 2mg per kg intravenously and intubated after paralysing with intermediate acting non depolarising muscle relaxant. General anaesthesia was maintained with volatile agents and oxygen nitrous oxide mixture during the surgery. Patient’s heart rate (HR), systolic blood pressure(SBP), diastolic blood pressure (DBP) were recorded prior to induction, at the time of intubation and at intervals of 1, 3 and 5 minutes after intubation. Mean arterial pressure (MAP) and rate pressure product (RPP) were calculated. At the conclusion of the surgery, patients were reversed using Inj. Neostigmine 0.05mg per kg and Inj.Glycopyrolate 0.01mg per kg and extubated. Any adverse effects of the medications were noted. The data was recorded and tabulated in a standard format. After completion of 100 cases, the data was analysed to compare the efficacy of Fentanyl and Esmolol to attenuate the haemodynamic response to laryngoscopy and intubation. Statistical analysis was done to assess the significance of differences between the two groups. Mean and standard deviations were calculated for all the readings. Two tailed paired student t tes was used to determine whether the observed differences were significant. P value of 0.05 or less was taken as significant at 95% confidence.
OBSERVATIONS AND RESULTS A total of 100 patients were enrolled for this study. All patients underwent elective surgical procedures under general anaesthesia. Table 1: Distribution of cases by gender
x2=0.36 p=0.548 ns Chi square test showed a p value of 0.543 for difference between the two groups with reference to gender composition. This p value was statistically not significant. Hence the two groups were comparable.
Table 2: Age and weight comparison
Heart Rate Table 3: Comparison of HR between fentanyl and esmolol groups
Systolic Blood Pressure Table 4: Comparison of systolic BP between fentanyl and esmolol groups
Diastolic Blood Pressure Table 15: Comparison of diastolic BP between the fentanyl and esmolol groups.
Mean arterial pressure Table 6: comparison of MAP between fentanyl and esmolol groups
Rate pressure product: Table 7: Comparison of RPP in fentanyl and esmolol group
Table 8: Difference From Preinduction To 5 Min
DISCUSSION A hemodynamic response of increased HR and BP to manipulation in the area of the larynx, by means of laryngoscopy and intubation, has been well recognized for 60 years. Stimulation of mechanoreceptors in the pharyngeal wall, epiglottis, and vocal cords is thought to be the cause for the haemodynamic response. The receptors are abundant over arytenoid cartilage, vocal cords, epiglottis and hypopharynx. Transitory hypertension and tachycardia are probably of no consequence in healthy individuals, but either one or both may be hazardous to those with hypertension, myocardial insufficiency or cerebrovascular diseases. The transient changes can result in potentially deleterious effect like left ventricular failure, pulmonary edema, myocardial ischemia and cerebral haemorrhage.4 Numerous studies have been published with different drugs to attenuate this response to laryngoscopy and intubation. In this study we have compared the efficacy of fentanyl and esmolol in attenuation the pressor response to laryngoscopy and intubation. We found that in the fentanyl group, the average heart rate increased by1.85% during laryngoscopy and intubation. In the esmolol group, the rise in heart rate was 3.1% which is higher than that of fentanyl group. The increase in heart rate in the esmolol group as a response to intubation was not statistically significant. However, at 5 min after intubation, the HR in fentanyl group was 8 bpm lower compared to esmolol group. P value for this difference was 0.001 making this very highly significant. Hence our study showed that Fentanyl is a better drug to control the tachycardia as a response to laryngoscopy and intubation. Gupta A et al37 found Esmolol beneficial in controlling tachycardia as response to laryngoscopy and intubation. Lars et al also found that esmolol controlled tachycardia.5 However Ranganathan et al38 found Fentanyl effectively supressed the tachycardia during intubation. Ebert et al (39)in their study found Fentanyl more effective than esmolol in controlling heart rate as response to laryngoscopy and intubation. Their finding was similar to the present study. On the contrary, Bostan et al found esmolol controlled HR better than Fentanyl.35 We found both fentanyl and esmolol effectively prevented rise of SBP as a response to intubation. In fact there was a fall of SBP noted in both the groups as compared to pre induction levels. When compared to fentanyl group, the average SBP was significantly lower in esmolol group during pre-induction and 3 min post intubation periods. Hence esmolol is more effective in controlling SBP as compared to fentanyl. DBP fell significantly in the fentanyl group as compared to esmolol group. Esmolol was also effective in supressing the rise of DBP, however there was no significant fall in DBP in esmolol group. However when the two groups were compared, there was no statistically significant differences in DBP. Both fentanyl and esmolol were effective in blocking the rise MAP as response to laryngoscopy and intubation. There was a statistically significant reduction in MAP in both the groups. MAP was significantly lower in the esmolol group in the pre induction period only. Both fentanyl and esmolol were able to prevent the rise of RPP as a response to laryngoscopy and intubation. In the fentanyl group, it reduced by a statistically significant amount. The RPP was significantly lower in the esmolol group during the pre induction period and 5 min after intubation. Ebert et al39 found that Fentanyl decreased the SBP, MAP and DBP significantly below the baseline, while these were either maintained at or elevated slightly in the esmolol group. Helfman et al.40 did not find any attenuation of the pressor response with 200 mcg fentanyl, however they intubated 2 minutes after study drug injection. Lars et al5 did not find any statistically significant difference in MAP between esmolol and placebo groups while our study showed esmolol effectively prevented rise of MAP during laryngoscopy and intubation. Gupta et al37 found esmolol effectively attenuated the rise of SBP and DBP as response to laryngoscopy and intubation. Yushi et al7 found fentanyl was more effective in controlling the stress response to intubation when compared to the stress response to laryngoscopy. Dahlgren and Masseter also found fentanyl effectively controlled the stress response to laryngoscopy and intubation. 29
CONCLUSION Based on findings of this study, we conclude that,
In conclusion, both fentanyl and esmolol are effective in attenuation of hemodynamic response to laryngoscopy and intubation. Fentanyl is more effective in preventing tachycardia while esmolol is more effective in controlling rise in systolic BP and rate pressure product.
REFERENCES
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