Infrared Pupillometry During General Anesthesia to Predict Pain
Primary Purpose
Postoperative Pain, Objective Assessment of Sedation
Status
Terminated
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Anesthesia Premedication, Induction and Maintenance
Pupillometry after administration of anesthetic drugs
Sponsored by
About this trial
This is an interventional diagnostic trial for Postoperative Pain
Eligibility Criteria
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
Sites / Locations
- Orthopedic Institute
Arms of the Study
Arm 1
Arm Type
Experimental
Arm Label
Intervention Group
Arm Description
all enrolled patients undergo the same protocol/ treatment: Anesthesia Premedication, Induction and Maintenance Pupillometry after administration of anesthetic drugs
Outcomes
Primary Outcome Measures
Pain in Recovery Room
Pain as assessed by visual analogue score at arrival of the patient in the recovery room Scale goes from 0-10, with 10 indicating the worst pain possible
Secondary Outcome Measures
Number of Patients we Were Able to Elicit a PLR Under Stable Experimental Conditions
Pupillary Reflex Dilation is measured intraoperatively at incision and at the end of the case as a possible indicator of success of regional anesthesia.
Measurement of this requires stable experimental conditions, most notably sufficient depth of anesthesia.
Full Information
NCT ID
NCT02058511
First Posted
February 4, 2014
Last Updated
February 13, 2019
Sponsor
University of California, San Francisco
1. Study Identification
Unique Protocol Identification Number
NCT02058511
Brief Title
Infrared Pupillometry During General Anesthesia to Predict Pain
Official Title
Intraoperative Use of Infrared Pupillometry During General Anesthesia to Predict Pain and Quality of Regional Anesthesia After Surgery
Study Type
Interventional
2. Study Status
Record Verification Date
February 2019
Overall Recruitment Status
Terminated
Why Stopped
Preliminary results showed no ability to predict pain by measuring hippus with pupillometry
Study Start Date
November 2012 (Actual)
Primary Completion Date
November 2016 (Actual)
Study Completion Date
November 2016 (Actual)
3. Sponsor/Collaborators
Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
University of California, San Francisco
4. Oversight
Data Monitoring Committee
No
5. Study Description
Brief 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
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.
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.
Detailed Description
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
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.
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.
6. Conditions and Keywords
Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Postoperative Pain, Objective Assessment of Sedation
7. Study Design
Primary Purpose
Diagnostic
Study Phase
Not Applicable
Interventional Study Model
Single Group Assignment
Masking
None (Open Label)
Allocation
N/A
Enrollment
24 (Actual)
8. Arms, Groups, and Interventions
Arm Title
Intervention Group
Arm Type
Experimental
Arm Description
all enrolled patients undergo the same protocol/ treatment:
Anesthesia Premedication, Induction and Maintenance Pupillometry after administration of anesthetic drugs
Intervention Type
Drug
Intervention Name(s)
Anesthesia Premedication, Induction and Maintenance
Intervention Description
The enrolled patients receive standard of care general anesthesia for knee arthroscopy. No additional pharmacological interventions are performed in study participants.
The administered drugs, as outlined in the arms section, are midazolam, fentanyl, propofol, and sevoflurane. Study patients receive analgesic drugs as needed in the recovery room if they experience pain.
Intervention Type
Procedure
Intervention Name(s)
Pupillometry after administration of anesthetic drugs
Intervention Description
All study patients receive the standard of anesthetic care. Every time a anesthetic drug has been administered, changes in pupillary oscillations will be recorded.
Assessment of pupil size and movements by shining infrared light into the eye and measuring the reflection over a 20 s period
The administered drugs are:
Midazolam 1-2 mg iv, Fentanyl 1mcg/kg body weight, Propofol for anesthesia induction 2-2.5 mg/kg body weight, Sevoflurane as needed for maintenance of general anesthesia.
Primary Outcome Measure Information:
Title
Pain in Recovery Room
Description
Pain as assessed by visual analogue score at arrival of the patient in the recovery room Scale goes from 0-10, with 10 indicating the worst pain possible
Time Frame
at arrival in recovery room
Secondary Outcome Measure Information:
Title
Number of Patients we Were Able to Elicit a PLR Under Stable Experimental Conditions
Description
Pupillary Reflex Dilation is measured intraoperatively at incision and at the end of the case as a possible indicator of success of regional anesthesia.
Measurement of this requires stable experimental conditions, most notably sufficient depth of anesthesia.
Time Frame
measurements were taken at two time points during surgery. Each measurement took 30 seconds
Other Pre-specified Outcome Measures:
Title
Hippus
Description
We assess the effects of various anesthetic drugs on pupillary unrest (hippus). More specifically, we record pupil diameters over 20 seconds and then perform a Fourier Analysis of the diameter changes. The endpoint variable is power of the oscillations over certain predefined frequency bins.
Time Frame
Before anesthesia start (baseline measurement) until discharge of the patient (on average 1-2 hours after arrival in the recovery room)
10. Eligibility
Sex
All
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
99 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
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
Facility Information:
Facility Name
Orthopedic Institute
City
San Francisco
State/Province
California
ZIP/Postal Code
94158
Country
United States
12. IPD Sharing Statement
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Infrared Pupillometry During General Anesthesia to Predict Pain
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