Infrared Pupillometry During General Anesthesia to Predict Pain
Status:
Terminated
Trial end date:
2016-11-01
Target enrollment:
Participant gender:
Summary
The study comprises of a series of pupillary measurements using infrared pupillometry in
patients undergoing arthroscopic knee surgery of any type.
Infrared pupillometry will be used to assess whether a painful stimulus results in pupillary
reflex dilation (PRD). The extend of the PRD may be an indicator how painful a stimulus is.
This may help to predict the amount of discomfort a patient will be experiencing after
emergence from general anesthesia.
In addition to measuring the pupillary reflex dilation, we will also measure oscillations of
pupil size before and after indiction of anesthesia, as well as during recovery. These
spontaneously occuring oscillations in pupil size, also called hippus, appear to be sensitive
to anesthetics and opioids. However, the effect of these drugs on hippus has not been
systematically addressed.
The aim of the study is
1. to identify whether regional anesthesia techniques such as femoral and sciatic nerve
blocks will block the PRD. This would allow assessment of block success in the
anesthetized patient.
2. to correlate the extent of the pupillary reflex dilation and hippus in the anesthetized
patient during and at the end of surgery with early postoperative pain scores and
subsequent analgesia requirements. Such correlation would allow to predict the amount of
postoperative pain before the patients emerge from general anesthesia.