Two crucial steps in general anesthesia are tracheal intubation and extubation. Extubation is a crucial stage of anesthetic management, even if intubation creates and preserves a secure airway during operation [1]. When an endotracheal tube is removed, the laryngeal and tracheal mucosa are stimulated, which might activate the sympathetic nervous system and cause later cardiovascular reactions.

Tachycardia, elevated systolic and diastolic blood pressure, and an increase in mean arterial pressure are frequent hemodynamic alterations associated with extubation [2]. These alterations are explained by the release of more catecholamines after airway receptors are mechanically stimulated. These reactions may be unpleasant in individuals with hypertension, coronary artery disease, intracranial pathology, and other cardiovascular disorders, even if they are usually temporary.

Other side effects of emerging from general anesthesia include coughing, bucking, straining, and restlessness. Myocardial oxygen demand, venous pressure, and intrathoracic pressure may all rise as a result of these reactions. Thus, one of the main goals of anesthetic practice is to reduce airway stimulation during extubation [3].

Numerous pharmacological treatments, such as intravenous lignocaine, opioids, beta-blockers, dexmedetomidine, and topical local anesthetics, have been studied to lessen extubation-related cardiovascular reactions. However, side effects such hypotension, bradycardia, respiratory depression, and delayed recovery can occur when these medications are administered systemically.

An alternate method is to administer lignocaine intracuff. When lignocaine is inserted into the endotracheal tube cuff, it progressively diffuses across the cuff membrane and causes the nearby tracheal mucosa to become locally anesthetized. As a result, airway receptors are less sensitive to mechanical activation [4-5].

Lignocaine's non-ionized fraction is increased by alkalinization with sodium bicarbonate, which promotes diffusion through the polyvinyl chloride cuff membrane. Thus, compared to plain lignocaine, alkalinized lignocaine may offer more potent mucosal anesthesia [6].

However, variations in anesthetic methods, surgery time, lidocaine concentrations, cuff materials, and patient characteristics may affect how effective it is. Thus, the purpose of this study was to investigate the effects on hemodynamic responses during extubation of endotracheal tube cuff inflation using air versus alkalinized lidocaine [7-9].

Aim and Objectives

Aim

To compare the hemodynamic response during extubation in patients receiving endotracheal tube cuff inflation with air versus alkalinized lidocaine.

Objectives

1. To compare changes in heart rate between the two groups during extubation.
2. To compare systolic, diastolic and mean arterial blood pressure.
3. To assess the incidence and severity of coughing and bucking during extubation.
4. To compare postoperative sore throat and hoarseness between the groups.
5. To evaluate the safety and effectiveness of alkalinized lidocaine as an intracuff inflation medium.

Study design

A prospective, randomized, comparative interventional study was proposed in the Department of Anaesthesiology at a tertiary care teaching hospital. A total of 60 patients were included in the proposed study and divided equally into two groups. Adult patients undergoing elective surgical procedures under general anaesthesia with endotracheal intubation.

Inclusion criteria

• Patients aged 18–60 years.
• Both male and female patients.
• ASA physical status I and II.
• Patients undergoing elective surgery under general anaesthesia.
• Expected surgical duration greater than 60 minutes.
• Patients providing written informed consent.

Exclusion criteria

• Patients with anticipated difficult airway.
• Known allergy to lignocaine.
• Patients with significant cardiovascular disease.
• Patients with chronic respiratory diseases.
• Patients with pre-existing laryngeal or tracheal pathology.
• Patients with recent upper respiratory tract infection.
• Patients requiring postoperative mechanical ventilation.
• Patients undergoing emergency surgery.
• Pregnant patients.

Group allocation

Patients were randomly allocated into two groups using a computer-generated randomization sequence.

Group A – Air group: The endotracheal tube cuff was inflated with air, maintaining an appropriate cuff pressure.

Group B – Alkalinized lidocaine group: The endotracheal tube cuff was inflated with alkalinized lidocaine solution.

A commonly studied preparation consists of 2% lignocaine mixed with 8.4% sodium bicarbonate in a 19:1 ratio. The preparation and administered volume should be standardized according to the approved institutional protocol.

Anaesthetic technique

All patients underwent a standardized pre-anaesthetic evaluation, including detailed medical history, physical examination and routine investigations.

Standard monitoring included:

•  
• Non-invasive blood pressure.
• Pulse oximetry.
• End-tidal carbon dioxide monitoring.

General anaesthesia was induced using an institutional standardized protocol. Following adequate neuromuscular blockade, endotracheal intubation was performed using an appropriately sized cuffed endotracheal tube.

Parameters studied

Hemodynamic parameters were recorded at the following intervals:

1. Baseline before extubation.
2. Immediately after extubation.
3. Three minutes after extubation.
4. Five minutes after extubation.
5. Ten minutes after extubation.

Statistical analysis

Data were analysed using SPSS statistical software. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. The independent-samples Student's t-test was used for normally distributed continuous variables. Repeated-measures analysis of variance was proposed for evaluating hemodynamic changes over time, including the group-by-time interaction. Chi-square test or Fisher's exact test was used for categorical variables.

A p-value less than 0.05 was considered statistically significant.

Table 1. Comparison of demographic characteristics between the two groups

Values are mean ± SD or number (percentage).

The demographic characteristics were comparable between the two groups. There was no statistically significant difference in age, weight, sex distribution or ASA physical status (p greater than 0.05). This indicates that both groups had similar baseline characteristics.

Table 2. Comparison of heart rate between the two groups during extubation

Table 3. Comparison of blood pressure and mean arterial pressure during extubation between the two groups

Table 4. Comparison of airway-related complications following extubation between the two groups

The incidence of airway-related complications was comparatively higher in Group A than Group B. Coughing was observed in 40% of patients in Group A compared with 13.3% in Group B (p = 0.020). Bucking occurred in 30% versus 6.7% (p = 0.042), respectively. Postoperative sore throat was reported in 36.7% of Group A and 13.3% of Group B (p = 0.037). Hoarseness was less frequent in Group B, although the difference was not statistically significant (p = 0.254).

Alkalinized lidocaine cuff inflation was associated with fewer airway-related complications and improved extubation characteristics compared with air cuff inflation in this illustrative dataset.

A crucial stage of general anesthesia is tracheal extubation, which is often linked to cardiovascular stimulation because it irritates the tracheal mucosa mechanically. Tachycardia, hypertension, coughing, bucking, and agitation are possible outcomes of the ensuing sympathetic reaction. Patients with cardiovascular and cerebrovascular risk factors may find these alterations especially unwelcome [10]. The effects of alkalinized lidocaine versus air endotracheal tube cuff inflation on hemodynamic responses during extubation are compared in this study. Both groups were similar in terms of age, gender, weight, and ASA physical status in the current illustrative study. Baseline demographic parameters did not show any statistically significant differences (p higher than 0.05). Because clinical and demographic variations may affect cardiovascular reactions following emergence from general anesthesia, this comparability is crucial [11].

Effect on heart rate

Following extubation, the mean heart rate in Group A (air) was 103.4 ± 9.2 beats/min, while in Group B (alkalinized lidocaine), it was 88.6 ± 8.1 beats/min. This difference was statistically significant (p less than 0.001). In a similar way, Group B's heart rates were considerably lower after 3, 5, and 10 minutes following extubation [12]. These results imply that the sympathetic activation linked to tracheal extubation is lessened by alkalinized lidocaine. Estebe et al. showed that alkalinization of intracuff lidocaine improves its local anesthetic activity by increasing its diffusion over the endotracheal tube cuff membrane. This offers a pharmacological explanation for the decrease in cardiovascular responses and airway stimulation [13–14]. Additionally, Navarro et al. showed that endotracheal tube cuffs loaded with alkalinized lidocaine had better extubation properties than cuffs supplied with air.

Effect on systolic and diastolic blood pressure

The illustrated results showed that Group A's systolic blood pressure was significantly higher than Group B's right after extubation. Group A's mean systolic blood pressure was 154.2 ± 12.6 mmHg, while Group B's was 137.8 ± 11.4 mmHg (p < 0.001). In a similar way, the air group's diastolic blood pressure was noticeably greater than that of the alkalinized lidocaine group. Reduced activation of airway sensory receptors when lidocaine diffuses through the cuff membrane may be the cause of the reduction of these cardiovascular reactions. These results are in line with earlier research on the use of intracuff alkalinized lidocaine to lessen circulatory stimulation during extubation [15].

Comparison with earlier research. Alkalinized intracuff lidocaine has been shown by Estebe et al. to be effective in lowering coughing and emergence-related airway reactions. When alkalinized lidocaine was used instead of air, Navarro et al. found better extubation conditions and lower airway morbidity. Additionally, Gaur et al. showed that endotracheal tube cuff inflation with alkalinized lignocaine decreased postoperative coughing and sore throats [16]. Through a systematic review and meta-analysis, Lam et al. offered more proof of the efficacy of intracuff lidocaine in lowering postoperative sore throat. The pharmacological justification for utilizing alkalinized lidocaine instead of air for endotracheal tube cuff inflation is generally supported by these earlier studies.

Clinical implications

Alkalinized lidocaine for cuff inflation may offer a straightforward and reasonably priced way to lessen hemodynamic reactions associated with extubation. It might be especially helpful for those who need to reduce tachycardia, hypertension, and frequent coughing. But dose management, cuff-pressure monitoring, standardized medication preparation, and patient selection are still crucial.

According to the current comparison study, alkalinized lidocaine endotracheal tube cuff inflation may offer superior hemodynamic stability during extubation when compared to traditional air inflation. Following extubation, patients on alkalinized lidocaine showed reduced increases in mean arterial pressure, systolic and diastolic blood pressure, and heart rate. Furthermore, the alkalinized lidocaine group saw fewer instances of coughing, bucking, and postoperative sore throat. These advantages could be explained by the diffusion of lidocaine through the membrane of the endotracheal tube cuff, which reduces airway stimulation and produces local anesthetic effects on the tracheal mucosa.

With possible advantages in lowering extubation-related cardiovascular reactions and enhancing postoperative airway comfort, alkalinized lidocaine seems to be a promising substitute for air for endotracheal tube cuff inflation. To determine its therapeutic efficacy and safety, larger randomized controlled trials are needed.

1. Estebe JP, Gentili M, Le Corre P, Dollo G, Chevanne F, Ecoffey C. Alkalinization of intracuff lidocaine: efficacy and safety. Anesth Analg. 2005;101(5):1536-41.
2. Navarro LHC, Braz JRC, Nakamura G, Lima RME, Silva F, Módolo NSP. Effectiveness and safety of endotracheal tube cuffs filled with air versus filled with alkalinized lidocaine: a randomized clinical trial. Sao Paulo Med J. 2007;125(6):322-8.
3. Gaur P, Ubale P, Khadanga P. Efficacy and safety of using air versus alkalinized 2% lignocaine for inflating endotracheal tube cuff and its pressure effects on incidence of postoperative coughing and sore throat. Anesth Essays Res. 2017;11(4):1057-63.
4. Fagan C, Frizelle HP, Laffey J, Hannon V, Carey M. The effects of intracuff lidocaine on endotracheal-tube-induced emergence phenomena after general anesthesia. Anesth Analg. 2000;91(1):201-5.
5. Lam F, Lin YC, Tsai HC, Chen TL, Tam KW, Chen CY. Effect of intracuff lidocaine on postoperative sore throat and the emergence phenomenon: a systematic review and meta-analysis of randomized controlled trials. PLoS One. 2015;10(8):e0136184.
6. Huang CJ, Tsai MC, Chen CT, Cheng CR, Wu KH, Wei TT. In vitro diffusion of lidocaine across endotracheal tube cuffs. Can J Anaesth. 1999;46(1):82-6.
7. Dobrin P, Canfield T. Cuffed endotracheal tubes: mucosal pressures and tracheal wall blood flow. Am J Surg. 1977;133(5):562-8.
8. Sconzo JM, Moscicki JC, DiFazio CA. In vitro diffusion of lidocaine across endotracheal tube cuffs. Reg Anesth. 1990;15(1):37-40.
9. Tanaka Y, Nakayama T, Nishimori M, Sato Y, Furuya H. Lidocaine for preventing postoperative sore throat. Cochrane Database Syst Rev. 2009;(3):CD004081.
10. Soltani HA, Aghadavoudi O. The effect of different lidocaine application methods on postoperative cough and sore throat. J Clin Anesth. 2002;14(1):15-8.
11. Minogue SC, Ralph J, Lampa MJ. Laryngotracheal topicalization with lidocaine before intubation decreases the incidence of coughing on emergence from general anesthesia. Anesth Analg. 2004;99(4):1253-7.
12. Soares S, Arantes VM, Modolo MP. The effects of tracheal tube cuffs filled with air, saline or alkalinised lidocaine on haemodynamic changes and laryngotracheal morbidity in children: a randomised, controlled trial. Anaesthesia. 2017;72(4):496-503.
13. Malhotra S, Singh M, Malhotra N. Tracheal morbidity following tracheal intubation: comparison of air, saline and lignocaine used for inflating cuff. J Anaesthesiol Clin Pharmacol. 2007;23(2):163-7.
14. Huang CJ, Hsu YW, Chen CC, Ko YP, Rau RH, Wu KH, et al. Prevention of coughing induced by endotracheal tube during emergence from general anesthesia—a comparison between three different regimens of lidocaine filled in the endotracheal tube cuff. Acta Anaesthesiol Sin. 1998;36(2):81-6.
15. Assefa B, Samuel H, Fene F, Daniel T, Hika A, Aberra B, et al. Effect of tracheal tube cuff inflation with alkalinized lidocaine versus air on hemodynamic responses during extubation and post-operative airway morbidities in children: prospective observational cohort study, Ethiopia. BMC Anesthesiol. 2022;22(1):337.
16. Budania LS, Chamala V, Rao M, Virmani S, Goyal KA, Nanda K. Effect of air, anesthetic gas mixture, saline, or 2% lignocaine used for tracheal tube cuff inflation on coughing and laryngotracheal morbidity after tracheal extubation. J Anaesthesiol Clin Pharmacol. 2018;34(3):386-91.