Infrared Pupillometry During General Anesthesia to Predict Pain
| Status: | Terminated |
|---|---|
| Conditions: | Post-Surgical Pain, Hospital |
| Therapuetic Areas: | Musculoskeletal, Other |
| Healthy: | No |
| Age Range: | 18 - 99 |
| Updated: | 2/17/2019 |
| Start Date: | November 2012 |
| End Date: | November 2016 |
Intraoperative Use of Infrared Pupillometry During General Anesthesia to Predict Pain and Quality of Regional Anesthesia After Surgery
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.
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.
The planned study is a prospective cohort study.
Patients undergoing arthroscopic knee surgery of any type (debridements, repair of anterior
(ACL) or posterior cruciform ligaments (PCL), meniscectomies, medial (MCL) or lateral
collateral ligament (LCL) repair, as well as microfracture surgery will be enrolled.
During anesthesia, 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. The PRD is measurable under general anesthesia in spite of the fact
that the patient does not "feel" or experience the painful stimulus.
The aim of the study is
1. to identify whether regional anesthesia techniques such as femoral and sciatic nerve
blocks (performed before the start of anesthesia) will block the PRD evoked by a painful
stimulus such electrical stimulation before procedure start. 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.
Knee arthroscopies are routinely performed under general anesthesia with or without regional
anesthesia, depending on the anticipated extent of surgery and the preferences of the
anesthesiologist and surgeon. The assessment of the PRD and/or hipppus before emergence would
identify those patients who would benefit from an additional nerve block before emergence to
achieve better pain control immediately postoperatively and to reduce the demand for
postoperative analgesics.
The planned investigation tries to achieve two novel findings. First, the measurement of the
PRD at the start of surgery will demonstrate whether a nerve block successfully blocks the
initial surgical stimulus. There is currently no method available that can assess block
success in the anesthetized patient. Secondly, the measurement at the end of the surgery
tries to predict the amount of pain following emergence from surgery. Pain may be experienced
by patients without nerve blocks as well as with nerve blocks, as the latter may have failed
or incomplete blocks, or may had a more extensive procedure that cannot be completely covered
by the block administered preoperatively. Identifying these patients may allow treatment to
minimize discomfort following emergence.
Pupillary reflex dilation describes the dilation of the pupil following a painful stimulus.
The dilation last several seconds. Pupillometry using an infrared pupillometer allows the
quantification of the reflex dilation. The PRD can be given a numerical value that reflects
the extent of the dilation. A recently published study demonstrated the correlation of the
extend of the PRD with pain scores and opioid requirements postoperatively. However, this
study was done in awake patients following surgery. The aim of this study is to predict
analgesia requirements in patients still under general anesthesia, before they experience
postoperative pain. We expect that infrared pupillometry during general anesthesia can
predict pain following surgery. Once this has been established, this knowledge and its
application would allow the anesthesiologist to initiate pain-relieving interventions such as
additional nerve blocks or administration of analgesics before emergence of the patients from
general anesthesia.
In addition to measuring the pupillary reflex dilation, we will also measure oscillations of
pupil size before and after induction of anesthesia, as well as during recovery. These
spontaneously occurring 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.
Patients undergoing arthroscopic knee surgery of any type (debridements, repair of anterior
(ACL) or posterior cruciform ligaments (PCL), meniscectomies, medial (MCL) or lateral
collateral ligament (LCL) repair, as well as microfracture surgery will be enrolled.
During anesthesia, 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. The PRD is measurable under general anesthesia in spite of the fact
that the patient does not "feel" or experience the painful stimulus.
The aim of the study is
1. to identify whether regional anesthesia techniques such as femoral and sciatic nerve
blocks (performed before the start of anesthesia) will block the PRD evoked by a painful
stimulus such electrical stimulation before procedure start. 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.
Knee arthroscopies are routinely performed under general anesthesia with or without regional
anesthesia, depending on the anticipated extent of surgery and the preferences of the
anesthesiologist and surgeon. The assessment of the PRD and/or hipppus before emergence would
identify those patients who would benefit from an additional nerve block before emergence to
achieve better pain control immediately postoperatively and to reduce the demand for
postoperative analgesics.
The planned investigation tries to achieve two novel findings. First, the measurement of the
PRD at the start of surgery will demonstrate whether a nerve block successfully blocks the
initial surgical stimulus. There is currently no method available that can assess block
success in the anesthetized patient. Secondly, the measurement at the end of the surgery
tries to predict the amount of pain following emergence from surgery. Pain may be experienced
by patients without nerve blocks as well as with nerve blocks, as the latter may have failed
or incomplete blocks, or may had a more extensive procedure that cannot be completely covered
by the block administered preoperatively. Identifying these patients may allow treatment to
minimize discomfort following emergence.
Pupillary reflex dilation describes the dilation of the pupil following a painful stimulus.
The dilation last several seconds. Pupillometry using an infrared pupillometer allows the
quantification of the reflex dilation. The PRD can be given a numerical value that reflects
the extent of the dilation. A recently published study demonstrated the correlation of the
extend of the PRD with pain scores and opioid requirements postoperatively. However, this
study was done in awake patients following surgery. The aim of this study is to predict
analgesia requirements in patients still under general anesthesia, before they experience
postoperative pain. We expect that infrared pupillometry during general anesthesia can
predict pain following surgery. Once this has been established, this knowledge and its
application would allow the anesthesiologist to initiate pain-relieving interventions such as
additional nerve blocks or administration of analgesics before emergence of the patients from
general anesthesia.
In addition to measuring the pupillary reflex dilation, we will also measure oscillations of
pupil size before and after induction of anesthesia, as well as during recovery. These
spontaneously occurring 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.
Inclusion Criteria:
- Patients older than 18 years undergoing arthroscopic knee surgery of any type
Exclusion Criteria:
- Blindness
- Anisocoria
- History of opioid abuse
- Chronic pain patients
- Gastric Reflux Disease (due to the use of laryngeal masks in the study)
- Non english speaking patients
- Cognitive impairment
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