Journal of Medical Sciences and Health

Introduction

Laryngoscopy and tracheal intubation marked the beginning of a new era of anaesthesiology practice and has led to a safer anaesthesia practice because of more control of airway and ventilation. A sympathoadrenal response is thought to be started by stimulation of epipharynx and laryngopharynx during laryngoscopy and tracheal intubation 1.These responses start within 5 sec, reaches a peak in 1-2 min and returns to baseline within 5 min 2, 3. These responses include increased circulatory catecholamines, heart rate (HR), Blood pressure (BP), myocardial oxygen demand and dysrthymias. Average increase in HR has been reported to be 23 beats and increase in blood pressure by 53/54 mm of Hg and decrease in left ventricular ejection fraction by 20%. A study was also conducted recently in 2021 which showed that there was peak rise in mean blood pressure by 3% after laryngoscopy and tracheal intubation 4. Although this response would likely to be tolerated by healthy patients, these changes may be associated with myocardial ischaemia and cerebral haemorrhage in those with a significant coronary artery or cerebrovascular disease 5. Hence, Effective attenuation of haemodynamic surge has become an important part in modern anesthesiology and various pharmacological methods have been tried for this. A wide variety of drugs are used to attenuate the hemodynamic response of laryngoscopy and intubation like Lignocaine 6, 7, 4, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, fentanyl 19, 20, 21, 22, 23, alfentanyl, ramifentanyl 24 nifedipine 25, beta blockers like, labetalol 26, metoprolol, esmolol, gabapentin, pregabalin, magnesium sulphate, ivabradine, dexmedetomidine 27, cloning 28. Lignocaine is an aminoethylamide and prototype of amide local anesthetic group. Introduced in the year 1948, it is the most widely used local anesthetic. Lignocaine has a better safety profile than the other agents used for airway anaethesia. Lignocaine has been used in several techniques of airway anaesthesai like nebulisation, topical spray and gel, transtracheal injection, Spray and you go (SAYGO) and nerve blocks. Each has advantages and disadvantages. Using nebulizer which is very readily available and simple technique, inhalation of aerosol of lignocaine is usually well tolerated and can anesthetize the entire respiratory tract 3. Following topical administration and its rate and extent of absorption depends upon concentration of total dose administered, the specific site of action and duration of exposure. The present study was undertaken to compare the efficacy of lignocaine 2% nebulisation versus oropharyngeal topical 10% xylocaine spray both @1.5mg/ kg before induction of anaesthesia in attenuating the pressor response to direct laryngoscopy and endotracheal intubation.

Methodology

After obtaining approval from hospital ethics committee, the study was conducted in the Department of Anaesthesiology and Murshidabad Medical College and hospital, West Bengal from January 2020 to February 2021. Based on the previous studies a sample size of 60 patients was taken in the age group of 18 to 45 years of either sex scheduled for routine elective surgical procedure (ASA grade I and II) under general anesthesia with endotracheal intubation were enrolled in the study. Patients with uncontrolled hypertension, significant hepatic or renal disease, antecipated difficult intubation, history of hypersensitivity to amide local anaesthetics, seizure disorder, patients taking any systemic medication and pregnant/lactating women were excluded from the study. Informed written consent was taken from each patient fulfilling inclusive criteria. Pre-anaesthetic check-up was done a day before surgery including a detailed history, a thorough physical and systemic examination and relevant demographic characteristics and baseline haemodynamic parameters were recorded. Routine investigations were done. Written informed consent was taken from the patient before including them in this study. Total 60 patients were randomly divided into two groups containing 30 patients in each group. Group A - Patients receive 4% lignocaine hydrochloride without preservative (Xylocard) given through nebulisation at 2mg/kg (2.5ml containing 100mg for a patient with 50kg weight) 3 minutes prior to laryngoscopy and intubation. Group B - Patients receive 10 puffs of topical spray with 10% lignocaine hydrochloride without preservatives (Xylocard) at 2mg/kg (100mg for a patient with 50 Kg weight) 3 minutes before laryngoscopy and intubation along with pre-oxygenation. Both the groups were double blinded by the sealed envelope method that means both the observer and the patients were unaware of the drug received in the sealed envelope. Heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) are documented 10 minutes before intubation, at the time of intubation, and 1,2 & 5 minutes after completion of laryngoscopy and intubation. After pre-oxygenation with 100% oxygen for 2 minutes, anesthesia was induced with 1.5 mg/kg propofol, followed by 1.5 mg/kg succinylcholine (muscle relaxant). After ventilation with 100 percent oxygen via a face mask for 1 minutes, endotracheal intubation was achieved using a Portex® ETT (cuffed). The cuff of the endotracheal tube was inflated until the cessation of air leakage around the tube. Inj. Fentanyl 2 mcg/kg is given intravenously after taking all post intubation readings. Isoflurane inhalation is added immediately after taking post intubation readings if there is no significant fall in blood pressure. Maintenance of anaesthesia was achieved with 60 per cent nitrous oxide in oxygen. Atrracurium is given intravenously when patient recovers from scholine relaxation. During anesthesia, a standard monitoring device to be used to non-invasively measure blood pressure and heart rate (HR). We also employed electrocardiography, pulse oximetry and capnography for monitoring. MBP, SBP, DBP, HR and peripheral oxygen saturation were recorded at the following time points: before the induction of anesthesia (baseline/ pre-induction); at 1, 2 and 5 minutes after endotracheal intubation. Outcome definition and parameters are HR (Heart rate), SBP (systolic blood pressure), DBP (diastolicblood pressure) and MBP (mean blood pressure) are the markers for hemodynamics stress response to laryngoscopes and intubation. The values obtained from each group are compared and comparison made among those two groups to assess the efficacy of nebulisation and topical lignocaine in suppression of hemodynamic surge.

Plan of Statistical analysis: Data will be entered in MS Excel and analyzed by SPSS Version 16.0 or later, IBM, Chicago USA. Unpaired independent t-test has been used for testing hypothesis about difference of arithmetic means between the 2 groups. Chi-square and Mann-Whitney U tests are used for comparing distribution of sex and mallampati classification among the participants of two groups respectively.

Results

Demographic data like age, sex, height and weight were compared and which are statistically not significant as shown in Table 1 that means these are comparable among the groups. When we compare heart rate among the groups, we can as per Table 2 that difference in heart rate at 2 minute and 5 minutes after intubation was statistically significant. When we compared the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Blood Pressure (MBP) among these two groups, we found significant difference in all these parameters 1 minute, 2 minutes and 5 minutes after laryngoscopy and intubation as shown in Table 3, Table 4, Table 5.

Discussion

The most important indications for attenuation of haemodynamic responses to laryngoscopy and endotracheal intubation, are in patients with Ischemic heart disease, hypertension and in patients with intracranial aneurysms 29, 30. Even these transient changes can result in potentially deleterious effects like left ventricular failure, pulmonary edema, myocardial ischaemia, dysrhthmias and cerebral haemorrhage. Lignocaine has been successfully used to blunt the haemodynamic responses 6, 7 due to the following properties: Suppression of the airway reflexes, effectively prevents and treat laryngospasm, good cough suppressant, myocardial depressant, peripheral vasodialation and antiarrythmic properties. The present study was undertaken to evaluate the efficacy of Lignocaine nebulisation vs topical lignocaine spray in the attenuation of hemodynamic surge during laryngoscopy and intubation in patients undergoing surgery under general anesthesia 8, 9. Attenuation in the SBP, DBP, MBP, HR were found statistically significant in the lignocaine nebulisation group when compared with the group receiving topical lignocaine spray. Our findings are similar to other studies 17, 18, 19. Our study is also in accordance with study conducted by Dhasmana S. Singh S. Pal US. J Maxillofac oral surg.2015 found lignocaine nebulisation is effective in airway block 31. Where Mostafa SM. Murthy BV. Barrett PJ. McHughP. Eur J Anaesthesiol in 1999 found orolaryngeal lignocaine spray cannot abolish haemodynamic stress response due laryngoscopy and intubation 32. Nebulizer is a readily available machine in OT complex, it is very simple to use, as well as it’s well tolerated to patients and it can anaesthetize the entire airway. The quality of topical anaethesia achieved with nebulisation is not as good as that achieved by the other techniques but use full options when other technique cannot be used or coughing is particularly undesirable. Where topical spray achieve rapid anaesthesia only to nose mouth and pharynx. Pressurized aerosol spray contains preservative that may cause sore throat postoperatively. Moreover most of the lignocaine applied with spray is swallowed and the absorbed drug metabolized in first-pass hepatic metabolism. It was found that there was better distribution of the drug via nebulisation in comparison to topical spray due to more duration available to achieve satisfactory topical anaesthesia 3. Further nebulisation resulted in better drug absorption from the pharyngeal and laryngeal area as well 33.

Conclusion

Lignocaine Nebulisation is more effective than topical lignocaine spray in attenuation of hemodynamic surge following laryngoscopy and intubation in patients undergoing surgery under general anaesthesia. This improved the safety profile of patients with hypertension, ischaemic heart disease, or any other comorbidites in which the haemodynamic surge could be harmful. Limitations of use of lignocaine nebulisation is in patients with history of allergy to local anaesthetic, asthma and pregnant patients as well as it cannot be used in emergency situation.