Influence of Depth of Anesthesia on Pupillary Reactivity to a Standardized Stimulus

The Influence of Depth of Anesthesia on Pupillary Reactivity to a Standardized Stimulus Under Steady-state Remifentanil Analgesia

A standardized tetanic stimulation is applied to patients under propofol-remifentanil TCI, in a cross-over fashion, at two different levels of anesthesia monitored by the BIS: BIS 25 and BIS 55. Remifentanil target remains constant during the whole study period (1 ng/ml). Pupillary reflex dilation is recorded after each stimulation.

Inclusion Criteria:

• ASA 1-2
• scheduled for an idiopathic scoliosis surgical correction

Exclusion Criteria:

• Ophtalmologic pathology
• Neurologic or muscular pathology
• Metabolic pathology
• Chronic pain