Stress Reaction
Conditions
Keywords
photoplethysmography, stress response
Brief summary
The effect of the location of tetanic stimulus on photoplethysmography signals will be studies in patients under general anesthesia.
Detailed description
A 5 second 100 Hz 70 mA tetanic stimulus will be applied to three different locations 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 photoplythysmography.
Interventions
DEVICETetanic Stimulus
5 second 100 Hz 70 mA tetanic stimulus will be applied to three different locations in a random order
Sponsors
University of California, San Francisco
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Surgical patients general anesthesia able to consent in english
Exclusion criteria
* regional anesthesia unable to consent in english under 18 yrs of age
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Photoplethysmography (PPG) | 1-2 minutes | Change in the PPG signal in response to tetanic stimulus. A tetanic stimulus will cause vasoconstriction which can be recorded as a decrease in PPG AC/DC. The outcome measure is the maximum decrease in AC/DC from baseline. Maximum decrease happens typically in 30-60 seconds after the stimulus. Thus, data was collected immediately before (baseline) and for 2 min after the stimulus. After the stimulus AC/DC values return to baseline in a few minutes. Baseline AC/DC measures a relative state of blood vessel tone. In anesthetized patients the AC/DC values can range from close to 0 to above 10. The higher the value, the more vasodilated the subject is. |
Countries
United States
Participant flow
Recruitment details
12 surgical patients were recruited between 10/3/19/2018 and 11/30/2018. All subjects completed the study. Study was conducted in surgical patients under general anesthesia at UCSF
Participants by arm
| Arm | Count |
|---|---|
| Intervention All subjects received the same intervention | 12 |
| Total | 12 |
Baseline characteristics
| Characteristic | Intervention | — |
|---|---|---|
| Age, Continuous | 49 years STANDARD_DEVIATION 18 | — |
| photoplethysmagraph AC/DC values 60 seconds before each tetanic stimulus was considered as the basee | 5.4 arbitrary units STANDARD_DEVIATION 1.95 | — |
| Race and Ethnicity Not Collected | — | — Participants |
| Region of Enrollment United States | 12 Participants | — |
| Sex: Female, Male Female | 8 Participants | — |
| Sex: Female, Male Male | 4 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
Photoplethysmography (PPG)
Change in the PPG signal in response to tetanic stimulus. A tetanic stimulus will cause vasoconstriction which can be recorded as a decrease in PPG AC/DC. The outcome measure is the maximum decrease in AC/DC from baseline. Maximum decrease happens typically in 30-60 seconds after the stimulus. Thus, data was collected immediately before (baseline) and for 2 min after the stimulus. After the stimulus AC/DC values return to baseline in a few minutes. Baseline AC/DC measures a relative state of blood vessel tone. In anesthetized patients the AC/DC values can range from close to 0 to above 10. The higher the value, the more vasodilated the subject is.
Time frame: 1-2 minutes
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Intervention | Photoplethysmography (PPG) | 3.3 arbitrary units | Standard Deviation 1.6 |