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

• Incidence of coughing during emergence and the first ten minutes after extubation. [ Time Frame: From emergence until 10 minutes after extubation ] [ Designated as safety issue: Yes ]
  

• Time elapsed between the bolus dose of remifentanil or lidocaine and extubation. [ Time Frame: From the administration of the study drug until extubation. ] [ Designated as safety issue: Yes ]
  
• Incidence of sore throat one hour after extubation. [ Time Frame: Assessed one hour after extubation. ] [ Designated as safety issue: Yes ]
  

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.