Efficiency of Intravenous Lidocaine to Reduce Coughing and the Hemodynamic Changes Associated to Tracheal Extubation

Coughing during tracheal extubation can be associated to adverse effects like tachycardia, arterial hypertension (AHT), increase of intracranial pressure (ICP) and intraocular pressure (IOP), and the dehiscence of surgical wounds. In ophthalmic, head and neck, and abdominal surgery, and in several other neurosurgical interventions it is vital to prevent these effects. The incidence of laryngeal irritation due to orotracheal intubation hinders patient comfort in the immediate postoperative (POP) period and no pharmacological intervention has been yet proven to prevent it.

At the end of the surgical procedure, the depth of the anesthetic plane decreases with the concomitant suspension of the anesthetic agents. However, the patient still requires ventilatory support through the endotracheal tube (EDT). The physical stimulation of the trachea created by this foreign body leads to the activation of the sympathetic nervous system, expressed in AHT, tachycardia, and ICP. To tolerate the EDT and prevent these effects, different maneuvers have been tested such as extubating the patient in a deep anesthetic plane or administering intravenous (IV) narcotics with the entailed complications: airway (AW) obstruction and hypercapnia, and the aspiration of an unprotected AW. Progress has been made with the introduction of ultrashort acting opioids, with significant statistical results. Moreover, beta-blockers, calcium channel blockers, angiotensin converting enzyme inhibitors and dexmedetomidine have been used to decrease the hemodynamic impact associated to tracheal extubation. The use of both IV and intratracheal lidocaine in doses ranging from 1 mg/kg to 3 mg/kg, has been studied with controversial results.

In view of the above, and as lidocaine is the most commonly used low-cost drug in all operating rooms with a good safety profile when used at low doses, the purpose of this study is twofold: to assess its effects at reducing coughing and to evaluate its hemodynamic impact when administering IV 1 mg/kg prior to extubation. Then, the efficiency of reducing the incidence of sore throats after the immediate POP shall be investigated.