Evaluation of Influencing Variables in Awakening Concentration and Concentration at Body Movements of Propofol TCI (Targeted Controlled Infusion) Targeted at the Effector Site
Condition: Awareness, Anesthesia
MeSH terms: Intraoperative Awareness
Study type: Observational

Summary: 
      Age has been related to awakening propofol concentration at effector site of TCI, but not to
      the loss of consciousness concentration, neither to the concentration of body movements
      during surgery, that can be interpreted as a sign of light anesthesia and lead to awareness.

      This study aims to determinate the incidence and the propofol TCI concentration at the
      effector site, in patients undergoing general anaesthesia without NBDs, of any patients body
      movements, defined as any spontaneous movements (but no reflex movements) during surgery.
    

Detailed description: 
      Target-Controlled-Infusion (TCI), estimating the effect-size concentration (Ce) of propofol
      and its elimination time with a computerized system, provides the anaesthesiologist useful
      information to guide anaesthesia.

      Although the correlation between propofol at the effector site at loss of consciousness (Ce
      LOC) and age is still debated with contrasting results, the correlation between propofol at
      the effector site at return of consciousness (Ce ROC) and age is well established, and some
      authors suggested that, due also for age-related changes in both pharmacokinetics and
      pharmacodynamics of propofol, its dosage should be reduced in elderly patients.

      Lowering propofol dosage however, can lead to an higher incidence of awareness during general
      anaesthesia, even if anaesthesia management is guided by consciousness monitors.

      Awareness during anaesthesia has recently been defined not as a binary phenomenon, but as a
      graded spectra of states and, during general anaesthesia without using neuromuscular blocking
      drugs (NBDs), body movement on the operating table can be taken as an indication of
      increasing probability of consciousness or 'light' anaesthesia.

      Hence, this study aims to evaluate the impact of age on the concentration at the effector
      site of propofol-remifentanil anaesthesia administered with TCI pump and without NBDs.
      Concnetration at the effector site of Propofol at the return of consciousness (CeP ROC) and
      at any clinical sign of superficialization such as body movements (CeP BM) will be
      considered.
    

Intervention name(s): We do not modify the normale general anesthesia delivery. We note the concentration of propofol at the effector site of body movementsand awakening
Intervention type(s): Drug
Intervention description(s): Propofol in our hospital is routinely delivered by Targeted Controlled Infusion (TCI) pumps. We note the concentration of propofol at the effector site of body movements and awakening
Intervention MeSH terms: Propofol
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        we recruited adult (> 18 years old) undergoing general surgery in Treviso Regional
        Hospital. We excluded patients with any neurological or psychiatric or cerebrovascular
        diseases and renal insufficiency in anamnesis, who were unable to understand the
        information contained in the informed consent form, and patients with intraoperative
        hemodynamic instability or who was delivered curare agents during anaesthesia.