Preoperative Topical Lidocaine Versus Intravenous Fentanyl to Obtund the Stress of Intubation Under Anesthesia.

Methodology

1. Study design Prospective randomized controlled trial. II. Study setting and location The study will be conducted in Kasr Al-Aini hospital (Cairo university hospitals) in elective surgical theatres.

III. Study population The study will be conducted on all elective surgical patients aged from 18 to 60 years requiring endotracheal intubation by direct laryngoscopy.

Total number of patients is 50 divided into two equal groups each containing 25 patients The two groups are group L (lidocaine) and group F (fentanyl). IV. Eligibility Criteria

1. Inclusion criteria

• American society of anesthesiologists class 1 or 2 (ASA 1 or 2) patients.
• Patients undergoing elective surgeries under general anaesthesia with endotracheal intubation using direct laryngoscope.
• Population aged from 18 to 60 years.

1. Exclusion criteria

• Patient's refusal to participate.
• ASA class 3 or more patients including substantive functional limitations; One or more moderate to severe diseases. Poorly controlled DM or HTN, COPD, morbid obesity (BMI ≥40), active hepatitis, alcohol dependence or abuse, implanted pacemaker, reduction of ejection fraction, ESRD undergoing regularly scheduled dialysis, history of MI, CVA, TIA, or CAD/stents, asthma with exacerbation, poorly controlled epilepsy.
• Patients with any degree of Hypertension or treated for hypertension.
• Pregnant patients.
• Age of participant less than 18 or more than 60 years.
• History of allergy to local anesthetics or opioids.
• Opioid abuse
• Anticipated difficult airway which will be defined as El-Ganzouri Risk Index (EGRI) score of 4 or more points.
• Difficult intubation which will be defined as situation where proper insertion of the tracheal tube with conventional laryngoscopy requires more than three attempts or more than 10 min.
• Difficult mask ventilation which will be defined as a situation that develops when it is not possible for the unassisted anesthesiologist to maintain the oxygen saturation >90% using 100% oxygen and positive pressure ventilation, or to prevent or reverse signs of inadequate ventilation.
• Patients requiring more than one attempt of intubation.
• Intubation time more than 30 seconds.
• Emergency surgeries or patients requiring rapid sequence induction for other reasons.

1. Study Procedures
2. Randomization (in RCT only)

Randomization will be carried out by a computer-generated list of random numbers then using closed envelope technique.

Total number of patients will be divided into two equal groups:

Each group will receive general anaesthesia using Propofol 1% 2 mg per kg and Atracurium besylate 0.5 mg per kg induction dose, however

1. Group L (lidocaine group) will receive topical lidocaine for airway anaesthesia (before induction of general anesthesia) at a total dose of 4.5 mg per kg divided as nebulized lidocaine at a dose of 3 mg/kg and lidocaine mouth rinsing and gargling at a dose of 1.5 mg per kg.
2. Group F (fentanyl group) will receive intravenous fentanyl at a dose 1 microgram per kg at induction of anesthesia.
3. Study Protocol

All patients recruited into the study will undergo pre-operative anesthetic assessment, evaluation, planning, fasting and informed consent will be obtained from them.

Inside the preoperative holding area 20-gauge peripheral intravenous cannula will be inserted and secured after application of local antiseptic.

Pulse oximeter and non-invasive blood pressure readings will be taken. No sedative premedication will be given. Group L (lidocaine) will receive a total dose of 4.5 mg per kg topical lidocaine 2% divided as 3 mg per kg nebulized lidocaine and 1.5 mg per kg lidocaine will be diluted to a total volume of 25 cc water before mouth rinsing and gargling, process of mouth rinsing and gargling will continue for 3 minutes, then patients will go to the operating room, while Group F (fentanyl) will receive nebulized, mouth rinsed and gargled 0.9% sodium chloride (normal saline). All patients will be instructed not to swallow the oral solution used for mouth rinsing and gargling.

Thereafter continuous pulse oximeter (SPO2), non-invasive blood pressure and electrocardiogram monitors will be applied on the patients before induction of anesthesia. Baseline SBP, DBP, MAP and HR will be recorded.

Ventilator will be already checked while emergency drug (atropine and ephedrine), hypnotic agent prepared (Propofol 1%) and muscle relaxant (Atracurium besylate) will be prepared. Adequately sized ventilator mask and direct laryngoscope having curved blade will be prepared (Macintosh type) as well as endotracheal tube size 7 for female and 7.5 size for male patients.

Pre-oxygenation with 100% oxygen for 3 minutes will be done to all patients.

Induction of intravenous anesthesia in both groups will be as the following:

Group F will consist of normal saline (instead of fentanyl), 2 mg per kg propofol 1% and 0.5 mg per kg atracurium, while group F will receive 1 microgram per kg fentanyl (fentanyl Hameln Pharmaceutical Germany), 2 mg per kg propofol 1%, 0.5 mg per kg atracurium and drugs will be flushed using iv crystalloid infusion.

Volume control ventilation will be initiated after propofol administration with FIO2:100%, respiratory rate 12/ minute, tidal volume of about 8 ml/kg ideal body weight, I:E ratio of 1:2, flow meter is set at 5 L/min and peep of 5 cm H20. Isoflurane at 1.2 % will be used as maintenance inhalational agent. After 3 minutes of atracurium injection intubation will be started. Endotracheal tube size 7 to be inserted in female while size 7.5 in males. After confirmation of endotracheal tube position, hemodynamics readings (heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure readings) will be taken immediately (1), 3, 6 and 10 minutes post intubation.

After extubation of each patient the incidence of laryngeal spasm will be noted while the patients will be asked about sore throat, dysphagia and hoarseness.

1. Measurement tools

• Patients' characteristics: age, weight, sex and height.
• Clinical parameters: continuous peripheral oxygen saturation (SPO2) and ECG but non-invasive arterial blood pressure (NIBP) will be monitored as mentioned earlier.
• Postoperative laryngeal injuries will be assessed by asking the patients postoperatively about the presence or absence of sore throat, dysphagia and hoarseness. 4- Secondary outcomes:
• Systolic, diastolic and mean arterial blood pressure at 1, 3, 6 and 10 minutes post intubation.
• Heart rate immediately (1), 3, 6 and 10 minutes post intubation.
• Incidence of post-operative sore throat, dysphagia and hoarseness.
• Incidence of laryngeal spasm after extubation.