Anesthesia Induction With Propofol or Sevoflurane in Patients Undergoing Fiberoptic Intubation for Cervical Myelopathy: Effects on Heamodynamics

Background: Fiberoptic intubation is the preferred method of intubation in patients with acute symptoms or signs of cervical myelopathy. This approach minimizes cervical spine movements to prevent new neurologic deficits or further neurologic injury, and is the safer method to secure the airways in patients with foreseen difficult intubation. In these patients anaesthesia induction is aimed to prevent cervical spine movements and to maintain hemodynamic stability. The most commonly reported technique for anaesthesia induction in patients with cervical myelopathy is based on local anaesthesia and propofol administration. Aim of this trial is to compare propofol-based anaesthesia vs. sevoflurane-based anaesthesia induction in patients with cervical myelopathy receiving oral or nasal fiberoptic intubation.

Methods: This randomized controlled trial is designed to prove equivalence. A series of 116 patients aged between 18 and 75 years, with cervical myelopathy will be enrolled. In all patients topical anaesthesia will be accomplished before anaesthesia induction. Patients will be randomly assigned to one of two anaesthesia induction strategies (sevoflurane + O2 + air or propofol + O2 + air). When loss of consciousness occurs (indicated by Bispectral index values between 40 and 50), oral or nasal fiberoptic intubation will be performed. The hemodynamic effects of the anaesthesia induction strategies will be assessed measuring mean arterial pressure at 4 time points: before anaesthesia induction (T1: baseline), at the end of anaesthesia induction when an adequate sedation level, with Bispectral index values 40-50, is achieved (T2: sedation steady state); immediately after placement of endotracheal tube (T3: intubation); five minute after tracheal intubation (T4: post-intubation). Secondary end-points of the study include the incidence of apnoea during induction process, diagnosed as absence of carbon dioxide trace for more than 10 seconds, the incidence of induction complications, defined as presence of laryngospasm, coughing and patient movement, and intubation conditions, defined as cord opening.

Discussion: We present the development phase of this anaesthesiological trial. A total of 40 patients have been enrolled from April 2009.