European Journal of Cardiovascular Medicine

Endotracheal intubation is a routine part of delivering general anesthesia. Post-operative sore throat is the most common complaint following tracheal intubation. Though not an incapacitating problem, it can be an uncomfortable one.1 It occurs in 90% of the intubated patients and is referred to as endotracheal tube induced emergence phenomenon as laryngeal edema and ischemia. Endotracheal tube cuff design, cuff pressure, lubrication and tube size are the important factors that affect the incidence and severity of sore throat. 2

Also other post intubation problems like hoarseness dysphonia, restlessness and post operative nausea and vomiting are seen.3 Despite satisfactory initial sealing of the cuff with air, N2O has been shown to diffuse into the cuff and increase the cuff volume and pressure resulting in an increased incidence of tracheal mucosal lesions.4 Inflating the cuff with liquid has been suggested to overcome this problem. 5,6

Plasma lignocaine level of 3μg/ml has been shown to supress endotracheal tube induced emergence, how ever intravenous lignocaine has shown to delay recovery.7 Topical lignocaine spray and jelly are associated with higher incidence of sore throat.8 Lignocaine has been to diffuse across cuff of the endotracheal tubes made of polyvinylchloride and alkalinisation could further enhance this diffusion, thus reducing the incidence and severity of post-operative sore throat and other problems that follow intubation. Present study was aimed to compare incidence of sore throat after endotracheal tube cuff inflation with air (or) lignocaine.

Present study was prospective, comparative study, conducted in department of anaestesiology, at Saveetha medical college, Chennai. Study duration was of 2 years (July 2022 to June 2024). Study was approved by institutional ethical committee.

After written informed consent taken from all participants, 60 Consenting patients undergoing general anaesthesia will be randomly assigned to one of the following two groups:

·         Group A (n = 30): Endotracheal tube cuff inflated with lignocaine.

·         Group B (n = 30): Endotracheal tube cuff inflated with air.

The process of randomization was based on a computer generated random-number table. All the patients were pre medicated with oral alprazolam 0.5mg and oral ranitidine 150mg the night before surgery. On the day of surgery on the table after securing IV-line inj. Glycopyrrolate 0.2mg IV, midazolam 1mg IV given. After three minutes of pre oxygenation, inj fentanyl 2mcg per kg was given and anaesthesia was induced with either propofol 2mg per kg and to facilitate endotracheal intubation succinylcholine 2mg per kg was used. After obtaining ideal intubating conditions, male patients were intubated with 8.0mm or 8.5mm and female patients with 7 or 7.5mm internal diameter oral tracheal tubes with a high-volume low presence cuff made of polyvinylchloride that were lubricated with sterile water.

In group 1: 2ml of 2% lignocaine preservative free was injected into the cuff

In group 2: cuff was slowly inflated with air to obtain minimal occlusive leak

Oxygen + nitrous oxide with sevoflurane 0.5 to 1% and increments of atracurium till the end of the surgery. At the end of the surgery 100% oxygen was administered and residual neuro muscular block was antagonised with glycopyrrolate 0.01mg per kg and neostigmine 0.05mg per kg. Gentle oral suctioning was done just before extubation. Trachea was extubated after deflating the cuff, when all the extubation criteria were met (full reversal of neuro muscular block, spontaneous ventilation, ability to follow oral commands, eye opening and hand grip).

1.       The gas and liquid volumes withdrawn from the cuff of the endotracheal tube were recorded

2.       Patients were asked for any complaints of sore throat by an anaesthetist blinded to groups and the degree of sore throat measured by visual analogue scale (0-100) at 15 minute, 1hour, 3hours, 12 hours and 24 hours following extubation.

3.       Cuff, hoarseness dysphonia restlessness and PONV were considered as secondary end points of emergence and evaluated in the six hours post extubation period.

Sample size was calculated based on previous studies. Data were analysed used independent T test and ANOVA ans repeated measure ANOVA wherever appropriate. P value <0.05 was considered significant.

In this study, two samples with sample size of 30 each and their readings related to Post Sore throat were taken in two methods: ETT Cuff with Lignocaine and ETT Cuff with AIR. It is noted, that in the category of ETT Cuff with Lignocaine, majority were from the age group of Below 30 years & in the age group of 31-40 years (36.7 %), followed by 41-50 years (23.3%) & above 50 years (3.3%). While, in the category of ETT Cuff with AIR, majority were from the in the age group of 31-40 years (43.3 %), followed by <30 years (23.3%), 41-50 years (20 %) & above 50 years (13.3%). In the category of ETT Cuff with Lignocaine, 46.7% of the patients are male and 53.3% of them are female. In the category of ETT Cuff with AIM, 36.7% of the patients are male and 63.3% of them are female. In the category of ETT Cuff with Lignocaine, 50% of the patients are reported with mild ASA and another 50% of them are reported with moderate ASA. In the category of ETT Cuff with AIM, 36.7% of the patients are reported with mild ASA and 63.3% of them are reported with moderate ASA.

Table 1: General characteristics

It is noted that the mean Sore Throat Post Intubation (Immediate Extubation) with Lignocaine (1.43) is significantly lesser than the mean Sore Throat Post Intubation (Immediate Extubation) with AIR (2.36). This shows that ETT Cuff with Lignocaine is better than ETT Cuff with AIR with respect to the Sore Throat Post Intubation (Immediate Extubation).

It is noted that the mean Sore Throat Post Intubation (After 3 hours of Extubation) with Lignocaine (0.56) is significantly lesser than the mean Sore Throat Post Intubation (After 3 hours of Extubation) with AIR (1.2). This shows that ETT Cuff with Lignocaine is better than ETT Cuff with AIR with respect to the Sore Throat Post Intubation (After 3 hours of Extubation).

Table 2: Comparison of Sore Throat Post Intubation (Immediate Extubation) ETT Cuff with Lignocaine and AIR

             ** Significant at1% level

Postoperative sore throat (POST) is a common problem following the use of endotracheal (ET) intubation during general anaesthesia (GA). It leads to dissatisfaction and discomfort after surgery and can delay a patient’s return to normal routine activities. POST has been rated by patients as the eighth most adverse effect in the postoperative period. The incidence of POST after ET intubation varies from 14.4–90%.

The postintubation-related emergence phenomenon is a cluster of airway complications associated with tracheal intubation or extubation after general anesthesia. Various symptoms result from mucosal injury or inflammation caused by airway instrumentation (ie, laryngoscope and suctioning) or the irritating effects of a foreign object (ie, endotracheal tube (ETT)). Postoperative sore throat (POST) is one of the most undesirable morbidities that occurs in approximately 50% or more surgical patients. During emergence from general anesthesia, patients may experience vigorous coughing, agitation or restlessness which might increase intracranial, intra-thoracic or intra-abdominal pressure, resulting in bronchospasm, wound dehiscence, and bleeding. Other laryngeal complication such as hoarseness, dysphonia, or dysphagia was also noted during the postoperative care.

Navarro LH9 conducted a randomised clinical study on 50 patients comparing ETT cuff inflation with 20cmH2O to ETT cuff filled with 2% lidocaine & 8.4% NaHCO3 to attain the same pressure. They observed that pressures in lidocaine filled endotracheal tube cuffs were significantly lower than the air filled cuffs (p<0.05) having lower systolic blood pressure at the time of extubation in lidocaine group (p<0.05) Another prospective randomised controlled study conducted by Pallavi Gaur & Pravin Ubale 10 on 100 patients aged between 18 to 65 years compared ETT cuff inflated with air versus ETT cuff filled with alkalinized lidocaine (2% lidocaine with 7.5% NaHCO3 in the proportion 19:1) and inflated to the pressure required to prevent air leak and measured using pressure manometer. It was seen that volume and pressure measured in the cuff at the end of the surgery were significantly higher in air group as compared to alkalinized lidocaine group (p<0.05) with incidence of coughing and post-operative sore throat being significantly higher in air group which is similar to our study. Malhotra et al..,11 study involved 100 adult patients aged, randomly allocated into two groups of 50 each: Group A (ETT cuffs inflated with air) and Group L (ETT cuffs inflated with alkalinized lidocaine). Group L demonstrated significantly attenuated hemodynamic responses compared to Group A. Mean HR, SBP, and DBP were notably lower in the alkalinized lidocaine group immediately post-extubation and 5 minutes later. No significant differences in oxygen saturation were observed between the groups. Inflation of ETT cuffs with alkalinized lidocaine effectively reduces hemodynamic stress during extubation compared to air inflation. This technique provides a simple and effective intervention for improving peri-extubation hemodynamic stability. Shah et al..,12 were separated into Group A – cuff inflated with air and Group L – cuff inflated with alkalinized lidocaine prepared by taking 9cc of 2% lidocaine and adding 1cc of sodium bicarbonate and using approximately 4-5 cc to inflate the cuff. Hemodynamic changes at baseline, induction, intraoperatively, during extubation and post-extubation were recorded.

Results: Haemodynamic responses were monitored at extubation & 2,4,6,8,10,15 minutes after extubation showed better hemodynamic stability in Group L than Group A.

Conclusion: The study suggested that endotracheal tube cuff inflated with alkalinized lidocaine have shown better hemodynamic stress response during extubation and post-extubation.

Regarding the lidocaine group, the decreased postoperative sore throat is due to continuous application of local anesthetic to the tracheal mucosa may reduce the occurrence of post-extubation laryngo tracheal morbidity. In vitro study showed that a local anesthetic-filled cuff diffused through the cough membrane in a dose-dependent fashion. 12 Relatively low concentrations of lidocaine could block different sensory tracheal receptors and suppress their action potentials. The reduction in the sore throat as a whole is related to the anti-inflammatory action of lidocaine. The half-lives of topical lidocaine in children aged 3 months to 9.5 years are 109 min.13

Limitations of the study were failure to measure the cuff pressure of the endotracheal tube cuff inflation was a major limitation of our study. Unable to randomize and double-blind, since it is an observational study was also another limitation.

On comparing the Sore Throat incidence Post Extubation between ETT Cuff inflation with Lignocaine and ETT Cuff with AIR, it is noted that Sore throat is reduced much in the method of ETT Cuff inflation with Lignocaine than ETT Cuff with AIR in both Immediate Extubation as well as in After 3 hours of Extubation. It is concluded that ETT Cuff with Lignocaine is effective than ETT Cuff with AIR in reducing the Sore throat.

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