optimal remifentanil dose for tracheal intubation without muscle relaxants: a randomized clinical trial

Muscle relaxants facilitate tracheal intubation, but in situations where their use is unnecessary or contraindicated, avoiding them seems logical. The aim of this study was to compare the effects of two doses of remifentanil combined with propofol and lidocaine for tracheal intubation without muscle relaxants. In a randomized clinical study 162 patients with ASA class I and II scheduled for elective surgery, were equally divided in to two groups receiving remifentanil 2 or 3μg/kg. All the patients received lidocaine 1.5 mg/kg and propofol 2 mg/kg.Laryngoscopy and tracheal intubation were performed 90 seconds after anesthesia induction. The status of laryngoscopy and tracheal intubation was assessed using status and movement of vocal cords, airway reaction and limbs movement. Blood pressure (BP) and heart rate (HR) were measured before anesthesia induction (as baseline), immediately and 3min after laryngoscopy.Results were compared between two groups using SPSS 15. There was a significant difference between two groups for vocal cord status (p=0.001) and movement (p=0.002) and limbs movement (p=0.013), but therewas no significant difference between two groups for airway reaction. However decline in BP and HR was confirmed in all the patients, but assessment of BP and HR in two groups showed that only decrease in systolic blood pressure was significant before drug administration compared to 3 min subsequent larynxgoscopy (p=0.002). HR showed significant difference between two groups only before drug administration with immediately after laryngoscopy (p=0.002). This study confirmed that combination of propofol, lidocaine and remifentanil (2 and 3 μg/kg) without muscle relaxants prepare appropriate situationfor laryngoscopy and tracheal intubation. However the higher dose of remifentanil was preferred, but associated with severe decline in BP and HR.