Effect of Lidocaine Sprayed for Attenuating Hemodynamic Response During Laryngoscopy and Intubation

The goal of this clinical trial is to to evaluate the efficacy of lidocaine sprayed at the laryngeal inlet combined with the endotracheal tube cuff compare with intravenous lidocaine on the hemodynamic response to laryngoscopy and intubation in patients undergoing elective neurological procedures during general anesthesia with total intravenous technique.

The main question it aims to answer is:

- Does topical lidocaine sprayed at the laryngeal inlet combined with the endotracheal tube cuff have more effect on stabilizing hemodynamic responses to laryngoscopy and intubation than intravenous lidocaine, in neurosurgical patients who undergo general anesthesia with total intravenous technique?

Participants will be recruited and randomized to receive either lidocaine spray (Group SL) or intravenous lidocaine (group IL) to blunt hemodynamic response to laryngoscopy and intubation.

Anesthetic protocol

* Preoperative

  * After the informed consent, all eligible patients will be fasting after midnight as it is an elective procedure.
  * No preoperative sedatives or analgesics were administered.
* Intraoperative Pre-induction phase

  * Standard monitors of electrocardiogram, noninvasive blood pressure (NIBP) is measured at upper extremity with BP cuff bladder length ≥ 80% and width ≥40% of patient's arm circumference and pulse oximeter were attached.
  * BIS (Bispectral index) was monitored
  * Hemodynamic baseline values of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded before the induction.

Intervention: prepared before induction anesthesia.

* Group SL: Spray 10% lidocaine for 4 puffs at the endotracheal tube cuff, also prepare for spray at the laryngeal inlet for 4 puffs (total approximately 1.5mg/kg).
* Group IL: 2% lidocaine 1.5 mg/kg IV will be given 2 minutes after cisatracurium injection (3 minutes prior intubation).

Induction phase

* Preoxygenation 100% oxygen, flow 6 liters per minute, for 3-5 minutes, target end tidal oxygen more than 90%
* Medication before the induction of anesthesia includes fentanyl 1.5 mcg/kg IV.
* General anesthesia will be induced with propofol target-controlled infusion (TCI) 4-6 mcg/ml IV, followed by cisatracurium 0.15 mg/kg IV for intubation.
* Bag mask ventilation will be started.
* The arterial line will be canulated before direct laryngoscopy and intubation and arterial line pressure transducer will be levelled at the phlebostatic axis and calibrate with NIBP.
* Intervention: Group IL: 2% lidocaine 1.5 mg/kg IV was given 2 minutes after cisatracurium injection.
* Direct laryngoscopy and tracheal intubation were done by an anesthesiologist, 1st (6 months experience), 2nd, and 3rd years anesthesiology resident.

At 5 minutes after cisatracurium injection, direct laryngoscopy will be performed, and spray 10%lidocaine directly to the epiglottis for 4 puffs for SL group.

* Tracheal intubation will be performed.
* The bispectral index (BIS) target range during intubation is 40 to 60.
* The hemodynamic parameters including mean arterial pressure(MAP) in mmHg, systolic blood pressure(SBP) in mmHg, diastolic blood pressure(DBP) in mmHg and heart rate(HR) in beats per minutes(bpm) and BIS will record during the peri-intubation period

All the adverse events (cough, pulmonary aspiration, desaturation, hypotension, hypertension, tachycardia, bradycardia, and arrythmia) will be noted as yes or no.

Eligibility Criteria:
Inclusion Criteria:

1. Age 18-65 years old
2. American Society of Anesthesiologists (ASA) physical status classification I-II

Exclusion Criteria:

1. History of lidocaine allergy
2. Predicted difficult airways
3. Body mass index \> 35 kilograms per meter squared
4. Risk aspiration
5. Baseline hemodynamic instability; heart rate \< 50 bpm, heart rate \> 120 bpm, blood pressure \< 90/60 mmHg, blood pressure \> 160/90 mmHg
6. Underlying disease: epilepsy, cardiovascular disease, heart failure, impaired cardiac function, severe renal dysfunction, impaired hepatic function, peripheral vascular disease
7. Pregnancy
8. Cerebral aneurysm, Arteriovenous malformation, Tumor size \> 4 centimeters, Brain herniation