Comparison of Two Induction Regimens Using Topical Lidocaine or Muscle Relaxant on Sore Throat and Hemodynamics

Comparison of Two Induction Regimens Using Topical Lidocaine or Muscle Relaxant; Impact on Postoperative Sore Throat and Haemodynamics

When a surgical procedure is performed under general anesthesia, the Airways are often secured With an endotracheal tube. Some patients experience sore throat thereafter. Studies have shown a reduction of these side effects when by use of muscle relaxants or a lidocain spray prior to the intubation. At Ostfold Hospital Trust, the investigators use one of the two methods or nothing. These methods will be studied systematically.

Heart rate and blood pressure rise during the intubation procedure. The investigators will also study the differences between the groups.

Post-operative sore throat and cough are common complications of endotracheal intubation and occurs in 30% to 70% of patients. Spraying with Lidocaine reduces this incident of postoperative sore Throat (POST). The use of neuromuscular blocking agents (NMBA) alone will also diminish the incidence of adverse postoperative upper airway symptoms. The use of topical Lidocaine is shown to reduce the cardiovascular responses during and after endotracheal intubation.

Hypertension and tachycardia as a response to endotracheal intubation are probably of little consequence in healthy individuals. These reactions might though be harmful in patients with cardiovascular diseases.

Postoperative sore throat is an undesired outcome for the patient. Topical or systemic pharmacological interventions is shown to reduce the POST.

Our anesthetists practice very different. The investigators sometime use topical lidocaine 2% as a spray, sometime muscle relaxants and often nothing but propofol and remifentanil prior to laryngoscopy an endotracheal intubation.

The objective of this study is to determine, whether the use of topical administered lidocaine, 2 %, has a better impact on POST compared with NMBA alone in general anesthesia with propofol and remifentanil. Patients receiving nothing but propofol and remifentanil will be the reference group. Assessment of the intubation conditions will be done according to a standard scheme

The primary endpoint:

• Differences in the intubation conditions between the three groups.
• Cardiovascular responses caused by the laryngoscopy and intubation.

The secondary endpoint:

• Post operative upper airways symptoms. Power and Sample Size Calculator To detect a decrease in the incidence of pharyngolaryngeal symptoms from 60% to 45%, we calculated that we needed 150 patients per study arm (power of the study, 0,8; type I error, 0,05).

450 adult patients have to be scheduled for the study.

The study is double blind, randomized:

• Group Topical lidocaine 4%:
• Group NMBA
• Control group Premedication: Paracetamol 2g General anaesthesia: TCI (Target Control of Infusion is a principle, an anesthesia infusion after protocol): Propofol and Remifentanil Surgical procedure: Not specified short lasting (<1 h) procedures The experienced anesthesiologist performing the intubating procedure will not be in the room until immediately before the intubation.

Postoperatively:

• Oral paracetamol and codeine-fixed combination up to 1000 mg and 60 mg, respectively, every 6 h
• When nausea and vomiting occurs postoperatively, ondansetron 4 mg IV administers as the drug of first choice followed by droperidol 0,625 mg IV if the nausea/vomiting persists.

Collected data:

• Patient characteristics inclusive smoke habits
• Intubation conditions according to the Copenhagen score
• Blood pressure prior to laryngoscopy and after 1, 3, 5, 7, 9, 11, 13 and 15 minutes, then every 15 min.
• Cuff pressure
• Pharyngolaryngeal discomfort 2 and 24 hours (telephone interview if released from hospital) after extubation

Inclusion Criteria:

• Scheduled elective surgery with general anesthesia and planned endotracheal intubation.

Exclusion Criteria:

• ASA≥3,
• 20>BMI<35
• Allergy to local anesthetics or neuromuscular blocking agents.
• The ASA physical status classification system is a system for assessing the fitness of patients before surgery. BMI is Body Mass Index measured in kilograms/square meter.