Stress Reaction
Conditions
Keywords
photoplethysmography, stress response
Brief summary
The effect of the location of tetanic stimulus on photoplethysmography signals will be studied in patients under general anesthesia.
Detailed description
A 5 second 100 Hz 70 mA tetanic stimulus will be applied to three different locations (Ulnar nerve, Facial nerve, Posterior Tibial nerve) in a random order in patients who are under general anesthesia. Tetanic stimuli are used routinely during general anesthesia to assess effectiveness of neuromuscular blockade. These tetanic stimuli are noxious stimuli that elicit a stress response which can be quantified using photoplethysmography. This study investigates if the magnitude of the tetanus induced stress response is dependent on the location of the tetanic stimulus as measured by photoplethysmography.
Interventions
DEVICETetanic Stimulus
5 second 100 Hz 70 mA tetanic stimulus will be applied to three different anatomical locations in each subject.
Sponsors
University of California, San Francisco
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Intervention model description
Each participant will receive three tetanic stimuli. They are applied to the same three anatomical locations in each subject, but the order at which they are delivered to these locations will be random.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Surgical patients * Undergoing general anesthesia * Able to consent in english * 18 years of age or older
Exclusion criteria
* Under 18 years of age * unable to consent in english * receiving regional anesthesia
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Tetanic Stimulus Induced Change in Photoplethysmography Light Transmission (in Analog to Digital Units as Measured Using a Pulse Oximeter) From Pre Stimulus Baseline | Maximum light transmission change from pre tetanic stimulus baseline within 60 seconds after the tetanic stimulus | Tetanic stimulation will induce peripheral vasoconstriction. This will be measured using photoplethysmography. During peripheral vasoconstriction the light transmission through finger will increase. The primary outcome will be the maximum change in light transmission (as measured by photoplethysmography) within 60 seconds after a tetanic stimulus as compared to pre stimulus baseline values. These maximal light transmission changes will be compared between the three different tetanic stimulus sites |
Countries
United States
Participant flow
Pre-assignment details
Stimuli were administered to three locations: A, B and C. Thus, there were 6 possible location sequences. ABC, ACB, BAC, BCA, CAB and CBA. These six location sequences were randomized in blocks of six (one of each) o that the sequence itself would not generate a bias. Thus, with 12 participants, each location sequence had two participants enrolled. For analysis the data for each location was pooled, independent of the location sequence.
Participants by arm
| Arm | Count |
|---|---|
| Tetanic Stimulus all participants receive the same intervention
Tetanic Stimulus: 5 second 100 Hz 70 mA tetanic stimulus will be applied to three different locations in a random order | 12 |
| Total | 12 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Protocol Violation | 1 |
Baseline characteristics
| Characteristic | Tetanic Stimulus |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 3 Participants |
| Age, Categorical Between 18 and 65 years | 9 Participants |
| Age, Continuous | 48 years STANDARD_DEVIATION 19 |
| Region of Enrollment United States | 12 participants |
| Sex: Female, Male Female | 6 Participants |
| Sex: Female, Male Male | 6 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 12 |
| other Total, other adverse events | 0 / 12 |
| serious Total, serious adverse events | 0 / 12 |
Outcome results
Primary
Tetanic Stimulus Induced Change in Photoplethysmography Light Transmission (in Analog to Digital Units as Measured Using a Pulse Oximeter) From Pre Stimulus Baseline
Tetanic stimulation will induce peripheral vasoconstriction. This will be measured using photoplethysmography. During peripheral vasoconstriction the light transmission through finger will increase. The primary outcome will be the maximum change in light transmission (as measured by photoplethysmography) within 60 seconds after a tetanic stimulus as compared to pre stimulus baseline values. These maximal light transmission changes will be compared between the three different tetanic stimulus sites
Time frame: Maximum light transmission change from pre tetanic stimulus baseline within 60 seconds after the tetanic stimulus
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Tetanic Stimulus | Tetanic Stimulus Induced Change in Photoplethysmography Light Transmission (in Analog to Digital Units as Measured Using a Pulse Oximeter) From Pre Stimulus Baseline | Location 1 | -50 percentage change from baseline value | Standard Deviation 19 |
| Tetanic Stimulus | Tetanic Stimulus Induced Change in Photoplethysmography Light Transmission (in Analog to Digital Units as Measured Using a Pulse Oximeter) From Pre Stimulus Baseline | Location 2 | -52 percentage change from baseline value | Standard Deviation 18 |
| Tetanic Stimulus | Tetanic Stimulus Induced Change in Photoplethysmography Light Transmission (in Analog to Digital Units as Measured Using a Pulse Oximeter) From Pre Stimulus Baseline | Location 3 | -44 percentage change from baseline value | Standard Deviation 19 |
Comparison: Maximum percent change from baseline (light transmittance) during 60 heart beats after the tetanic stimulus were compared between the three stimulus locations using ANOVAp-value: 0.65ANOVA