Study area

This study was conducted in Tikur Anbessa specialized Hospital (TASH) which is one of the largest teaching and referral hospitals in Addis Ababa, the capital of Ethiopia.

Study design and period

A prospective institutional-based observational cohort study was employed from October/2019-February/2020.

Source populatio

All children operated on under general anesthesia with cuff-inflated endotracheal tube intubation at Tikur Anbessa Specialized Referral hospital.

Study population

All elective children aged 3–13 years who undergo operation under general anesthesia with endotracheal tube intubation for greater than one-hour during the study period.

Study variables Independent variable

Socio-demographic variables like (Age and sex, Duration of surgery, duration of anesthesia, ASA status, and nature of surgery).

Dependent variable

Hemodynamic response changes (HR, SBP, AND DBP), cough, sore throat, and hoarseness.

Inclusion criteria

All Children aged 3– 13 years, of ASA physical status 1 or 2 undergoing elective surgery under general anesthesia requiring oral tracheal intubation were considered eligible for inclusion in the study.

Exclusive criteria

Those with oropharyngeal or neck malformations, patients who had previously required tracheal intubation or a tracheostomy, the presence of stridor or dysphonia, and those requiring surgery to the neck, larynx, or oropharynx.

Sample size and sampling technique

The sample size was calculated with the incidence of sore throat that was observed in the post-anesthesia care unit after tracheal extubation, by using the study done in Brazil [14]. Taking these, the sample size was calculated based on double population proportion formula. For a type, one error of 0.05 and type two error of 0.2 with a power equal to 80% and confidence interval of 95%. thus, the sample size was 56 patients with 28 patients in each group.

P1(1−p1)+p2(1−p2)

(P1−p2)2

0.02(1−0.02) + 0.2(1−0.2) *2.71 = 24.98

(0.2−0.02)2

n = Sample size in each group

α = significance level (1.96)

1-β = power of study at 80% (0.84)

q1= 1−p1

q2=1−p2

p1 = incidence of postoperative sore throat in the lidocaine group.

p2 = incidence of postoperative sore throat in the air group.

It was approximated to 28 for each group, when 10% of contingency is included by assuming a loss to follow up, a total sample of 56 patients or 28 patients per group was required.

Procedure

From situational analysis, during the study period, 165 children were estimated to undergo surgery under general anesthesia with cuffed endotracheal tube intubation in the hospital. With systematic random sampling, every 3rd (165/56 = 2.9) elective patient from the schedule, who fulfilled inclusion criteria, and volunteers were recruited to take part in the study. The first sample was selected by lottery method from scheduled patients listed on the display board on the first day of the study period, the patients were not randomized for anesthetic management.

All patients were visited in the morning before surgery; informed consent was obtained, and follow-up should be started. On arrival in the operating room, all patients were attached to ECG, pulse oximetry, temperatures, and non-invasive blood pressure monitoring. At the induction of anesthesia, a patient breathes 100% oxygen via a facemask, and then, all patients were anesthetized according to a standard protocol and preferences of the respective anesthetists, who handle the case.

All patients were pre-oxygenated and received thiopentone for induction and suxamethonium, depolarizing muscle relaxant for facilitating laryngoscopy. Laryngoscopy was performed and the trachea was intubated with a standard cuffed endotracheal tube according to the patient’s age. The endotracheal tube cuff inflation whether alkalinized lidocaine or air was, under the preferences of anesthetists who manage (handle) the case. The cuff was inflated until there was no air leak around the tube when positive pressure was applied. Alkalinized lidocaine used to inflate the tubes was prepared by mixing 19 ml of lidocaine 1% and 1ml of sodium bicarbonate solution. The total amount of alkalinized lidocaine used for inflation was 1ml to 2ml.

Isoflurane was the maintenance agent that was used in both groups, Vecuronium was the muscle relaxant that was used for anesthetic maintenance in all patients, and the reversal agent was neostigmine.

Data collection

The evaluated demographic and clinical characteristics of the study participants were: Gender, age, ASA physical status, nature of the surgery, duration of surgery, and duration of anesthesia. Evaluated hemodynamic parameters were systolic blood pressure, Heart rate, and Diastolic Blood Pressure. The assessed Postoperative laryngotracheal morbidities were: Postoperative cough, hoarseness, and sore throat.

Data collection technique and instrument

Data were collected using a pretested observational checklist. Data collectors were one bachelor’s degree holder anesthetist and two bachelor’s degree holders nurse and they were supervised by one master’s degree holder anesthetist. Questionnaires were prepared in both English and Amharic languages and it was divided into three parts, the first one was filled in the preoperative and intra-operative time and collected by one trained BSc anesthetist and the second one was PACU record going to be recorded by a PACU nurse and the third one was filled in the ward which was filled by trained ward nurse [26].

Data processing and analysis

The Data was entered using the Epi-Info version 7.0 and clean-up has been made to check accuracy, consistency, and errors. Errors identified were corrected and finally, the data was transported to SPSS Version 20 for analysis. The normality of the data distribution was analyzed by the Shapiro-Wilk test for non-normally distributed data and the histogram with bell-shape for normally distributed data. while homogeneity of variance was assessed using Levene’s test for equality of variance. Numeric data were described in terms of mean ± SD for symmetric data [26].

Operational Definition:

Sore throat

A constant pain or discomfort in the throat independent of swallowing.

Hoarseness

Difficulty in speaking or pain in speaking.

Cough

A sudden reflex that forces air out of the throat.

Alkalinized Lidocaine

Is a solution that is prepared by mixing 19 ml lidocaine 1% or 2% with 1 ml sodium bicarbonate 8.4% solution.

ASA status

a surgical risk stratification validated by the American Society of Anesthesiologists.