Bilateral Bispectral Index, Asymmetries and Post-operative Delirium

Bilateral Bispectral Index and Asymmetries in High Risk Patients for Posteoperative Delirium: An Observational, Prospective, Exploratory Study

The primary objective of the study is to describe the value of interhemispheric asymmetry (ASYM), during the different intra- and peri-operative phases, in those patients who develop or do not develop post-operative delirium (POD) during the first 30 post-operative days and postoperative cognitive disfunction (POCD) in the first 90 post-operative days, in a population undergoing head&neck and plastic surgery with a priori increased probability of POD.

Values of the study variables will be extract in these specific moments (considering a delay of thirty seconds between the in vivo phenomenon and the instrument): (t1) BIS probe application (t2) 60" before GA administration (t3) 60" after myoresolution (t4) intubation (t5) surgical incision (t6) end of ipnosis (t7) 10 minutes after extubation. Daily follow-up for the first five post-operative days is performed in order to verify the onset of POD and a telephone follow-up at thirty and ninety post-operative days in order to verify the onset of POD / POCD.

CAM scale will be used for the diagnosis of POD; while for the diagnosis of POCD, 6-CIT test will be used, the EQ50 test in the case of tracheostomized patients.

Inclusion Criteria:

-Patients, undergoing head&neck surgery, who have at least 3 of the following criteria (to establish "a priori" increased risk of POD):

• Age> 70;
• Male sex; or ASA III;
• Smoker;
• High blood pressure;

Exclusion Criteria:

• ASA IV, V or ASA IE, IIE, IIIE (patients with anesthetic risk ASA>III and those undergoing urgent-emergency surgery will be excluded from the study);

• Past positive medical history for:

  • Stroke;
  • Dementia;
  • Cerebral aneurysm;
  • Intracranial mass;
  • Head trauma;
  • Epilepsy;
  • Diabetes mellitus;
  • Previous neurosurgical intervention;
  • Psychiatric illnesses requiring chronic treatment;

• Patients undergoing surgery in the previous two weeks;

• Patients whose hospitalization duration is estimated to be less than five days;

• Lack of understanding of the Italian language or English;

• Age <18 years.