Efficacy of Remifentanil Compared to Lidocaine on the Incidence of Coughing During Emergence of Anesthesia

Emergence is an important period of general anesthesia during which several problems can occur. Coughing, hypertension, tachycardia and agitation have been observed during emergence of general anesthesia.

Most patients will cough during emergence. Different techniques and drugs have been studied to reduce coughing during emergence. Among others, the role of lidocaine given intravenously, topically , or intra-cuff has been studied.

There is some evidence supporting the administration of intravenous opioids prior to emergence of general anesthesia to reduce perioperative coughing, agitation and haemodynamic stimulation. However, depending on the type of opioids given, this may delay the emergence from anesthesia. The effect of a remifentanil infusion given in combination with isoflurane as the volatile agent has been shown to reduce the incidence of perioperative coughing without delaying the emergence of anesthesia. The effect of a small bolus of remifentanil given prior to emergence to prevent perioperative coughing has yet to be studied.

Desflurane is a newer volatile agent allowing early recovery from anesthesia. This agent has led to earlier discharge and more rapid resumption of normal activities after surgery. However, an incidence of coughing around 70% has been reported after a desflurane-based anesthesia.

This study will compare the effects of remifentanil (bolus dose of 0.25 mcg/kg or 0.5 mcg/kg) to lidocaine (bolus dose of 1mg/kg) when given prior to emergence to prevent perioperative coughing after a desflurane-based anesthesia.

Methods:

• Induction of general anesthesia: 1.5-3 mg/kg propofol and 1-3 mcg/kg fentanyl. Neuromuscular relaxation at the discretion of the attending anesthesiologist.
• Tracheal intubation using direct laryngoscopy.
• Maintenance of general anesthesia: desflurane between 0.7 and 1.0 MAC, fentanyl 1 mcg/kg. Neuromuscular relaxation will be carried out at the discretion of the attending anesthesiologist.
• No opioids should be given during the last 30 minutes of surgery.
• Reversal of neuromuscular blockade is mandatory at the end of surgery.
• At the end of surgery : discontinuation of desflurane.
• Administration of the study drug: (bolus dose of remifentanil 0.25 mcg/kg, remifentanil 0.5 mcg/kg or lidocaine 1 mg/kg).
• When the expired fraction of desflurane reaches 0.2 MAC, the patient will be asked to open his eyes every 30 seconds.
• After eyes opening, ventilator will be stopped and the extubation performed.
• Number of coughing episodes and their importance will be rated on a scale from 0 to 3 by a blinded observer during emergence and the first ten minutes after extubation.
• Time elapsed between the administration of the bolus dose of the study drug to extubation will be recorded.
• The presence of sore throat will be assessed one hour after extubation.

Inclusion criteria

• Patients aged 18-80 years
• ASA physical status 1-3
• Patients undergoing elective surgery under general anesthesia requiring endotracheal intubation (excluding head and neck surgery)

Exclusion criteria

• Current use of ACE inhibitor
• Chronic cough
• Asthma or severe COPD
• Pulmonary tract infection
• Anticipated difficult intubation
• Current use of opioids
• Current use of cough medicine
• Contraindication to remifentanil or lidocaine
• Pregnancy
• Symptomatic cardiac, renal or hepatic disease