Anesthesia
Conditions
Brief summary
At present clinicians have no way to reverse anesthesia. Patients wake when their bodies clear the anesthetic. Most people wake quickly, but some do not. All patients have memory and other cognitive problems after waking from anesthesia. In studies on animals, the investigators observed that caffeine caused rats and mice to wake much more rapidly from anesthesia. This was true for all the animals tested. The investigators would like to see if this holds true in humans. Will caffeine accelerate waking from anesthesia? Will it reverse the cognitive deficits associated with anesthesia, after waking? The investigators carried out a modest trial with 8 test subjects. Each volunteer was anesthetized twice. Each volunteer was anesthetized one time and received an infusion of saline (placebo control), without the aid of any other drugs and the other time the volunteer received an infusion of a relatively low dose of caffeine. The order of saline versus caffeine was randomized and the study was done in a double blind manner. We observed that emergence from anesthesia was significantly accelerated by the caffeine infusion. No adverse events were observed.
Interventions
DRUGCaffeine
Anesthetized volunteers will be allowed to wake after injection of caffeine (15 mg/ kg). The time to wake will be measured.
DRUGPlacebo Control
Anesthetized volunteers will be allowed to wake after injection of saline (placebo control). The time to wake will be measured.
Sponsors
National Institutes of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
University of Chicago
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
25 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
1. Age 25-40. 2. Male. 3. Normal healthy subject without systematic diseases or conditions. 4. Metabolic Equivalents of Functional Capacity \>= 5. 5. Low risk for Obstructive Sleep Apnea (OSA) based on the screening test (STOP-bang score established by American Society of Sleep Apnea): Yes to \> 3 items- high risk of OSA 6. No History of Arrhythmia (Baseline EKG will be obtained during the history and physical session), seizure, liver and kidney diseases. 7. BMI \< 30 kg/m2. 8. No history of prior difficulty with anesthesia. 9. No personal or family history of malignant hyperthermia. 10. No history of any mental illness. 11. No history of drugs or alcohol abuse (urine drug screens required). 12. Subjects capable of giving consent. 13. Living less than 30 miles away from University of Chicago. 14. No history of seizure disorders. 15. No history of head trauma.
Exclusion criteria
1. Age \<25 or \>40. 2. Female. 3. ASA physical status \> 1 (normal healthy subject without systematic diseases or conditions) 4. Metabolic Equivalents of Functional Capacity (METs) \< 5. 5. High risks for Obstructive Sleep Apnea (OSA) based on the screening test (STOP-bang score established by American Society of Sleep Apnea): Yes to \> 3 items- high risk of OSA 6. History Arrhythmia (Baseline EKG will be obtained during the history and physical session), seizure, liver and kidney diseases 7. BMI\>30 kg/m2. 8. Prior difficulty with anesthesia. 9. Personal or family history of malignant hyperthermia. 10. History of any mental illness. 11. History of drugs or alcohol abuse (urine drug screens required) 12. Subjects capable of giving consent 13. Living more than 30 miles away from University of Chicago. 14. History of seizure disorders. 15. History of head trauma.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Waking Time - Re-establishment of the Gag Reflex. | followed from the end of anesthesia to gag reflex, up to 2 hours | The goal of the study is to determine whether caffeine speeds emergence from anesthesia. The time between terminating delivery of anesthetic and the subject starting to gag was measured. Anesthesia suppresses the gag reflex. Immediately after anesthetizing the test subject, a laryngeal mask airway (LMA) device was inserted into the test subject airway. After anesthesia was terminated and emergence from anesthesia was taking place, the gag reflex was re-established, and the LMA produced a gag response in all test subjects. This objective and unequivocal measurement constituted the emergence time for each subject. The emergence time was defined as the time between terminating the anesthesia and the test subject starting to gag. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cognitive Test1 - Visual Analog Scale --- Feel Bad | Test was given at 15, 30, 45, 60, 75, 90, 105 and 120 minutes after terminating anesthesia. | Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. Fifteen minutes after terminating anesthesia each subject was asked to complete a series of psychomotor tests, if they were able. Otherwise the testing started at 30 minutes. The tests were repeated every 15 minutes. The first test, a visual analog scale (VAS) test consisted of two 100-mm lines, each labelled with of feel good or feel bad displayed on a computer screen. Test subjects were asked to rate how they currently felt by placing a cursor on each of the line (0=not at all, 100=extremely). The test repeated every 15 minutes. |
| Cognitive Test2 - Sternberg Test of Memory | Test was given at 15, 30, 45, 60 minutes after terminating anesthesia. | Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. The test was first applied at 15 minutes following anesthesia, if the subject was awake and then repeated every 15 minutes. In the Sternberg Test of Memory (STM) participants were asked to memorize a string of numbers. Afterwards, a computer would flash a series of random numbers on the screen and the participant was asked whether the number on the computer screen was part of the earlier string or not. In three rounds, participants were given a string of 2, then 4, then 6 numbers. The latency until the subject answered the question was monitored and this is the data summarized here. |
| Cognitive Test3 - Divided Attention Task | Test was given at 15, 30, 45, 60 minutes after terminating anesthesia. | Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. The test was first applied at 15 minutes following anesthesia, if the subject was awake and then repeated every 15 minutes. In the Divided Attention Task (DAT), participants were asked to fly an airplane over the center of a winding road with a joystick and simultaneously press a button whenever targets randomly flashed on the screen. The computer program tracked the root mean squared (RMS) deviation of the plane from the center of the road and the latency for pressing the trigger when the target appeared. |
| Cognitive Test1 - Visual Analog Scale --- Feel Good | Test was given at 15, 30, 45, 60, 75, 90, 105 and 120 minutes after terminating anesthesia. | Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. Fifteen minutes after terminating anesthesia each subject was asked to complete a series of psychomotor tests, if they were able. Otherwise the testing started at 30 minutes. The tests were repeated every 15 minutes. The first test, a visual analog scale (VAS) test consisted of two 100-mm lines, each labelled with of feel good or feel bad displayed on a computer screen. Test subjects were asked to rate how they currently felt by placing a cursor on each of the line (0=not at all, 100=extremely). The test repeated every 15 minutes. |
| Minute Ventilation | Continuous monitoring from time lma inserted until subject started to gag and it was removed, up to 2 hours post-anesthesia. | The volume of gas inhaled or exhaled from a person's lungs per minute. We wished to determine whether caffeine altered minute ventilation. |
| Mean Arterial Blood Pressure | Continuous monitoring from start of anesthesia until discharge of test subject, up to 2 hours post-anesthesia. | This measurement was made in order to determine whether caffeine altered blood pressure in a deleterious manner. |
| Heart Rate | Continuous monitoring from start of anesthesia until discharge of test subject, up to 2 hours post-anesthesia. | This measurement was made in order to determine whether caffeine altered heart rate in a deleterious manner. |
| Bispectral Index | Continuous monitoring from start of anesthesia until discharge of test subject, up to 2 hours post-anesthesia. | A bispectral index (BIS) measurement system was employed to measure depth of anesthesia. Using electrodes attached to the forehead to measure EEG, BIS outputs a dimensionless number between 0 and 100 that is proportional to the brain concentration of anesthetic and is thereby proportional to an individual's level of consciousness (Greenwald S, Chiang HH, Devlin P, Smith C, Sigl J, Chamoun N: The Bispectral Index (Bis2.0) as a Hypnosis Measure. Anesthesiology 1994; 81: A477-a477). When the test subjects arrive, prior to anesthesia, their BIS values are in the range of 95 - 99. That corresponds to an awake and alert state. During anesthesia, most subjects are in the range of 20 - 40, corresponding to an anesthetized state. As the anesthetic wears off, the BIS values rise until they are back in the 95 - 99 range that they were prior to anesthesia. In particular, we wished to determine whether BIS exhibited more rapid recovery after caffeine infusion as compared to saline (control). |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| All Study Participants Participants who were randomized to either receive Caffeine then Placebo or Placebo then Caffeine | 8 |
| Total | 8 |
Baseline characteristics
| Characteristic | All Study Participants |
|---|---|
| Age, Continuous | 31 years STANDARD_DEVIATION 4.3 |
| Race/Ethnicity, Customized Asian | 2 Participants |
| Race/Ethnicity, Customized Black | 3 Participants |
| Race/Ethnicity, Customized White | 3 Participants |
| Region of Enrollment United States | 8 participants |
| Sex: Female, Male Female | 0 Participants |
| Sex: Female, Male Male | 8 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 8 | 0 / 8 |
| other Total, other adverse events | 0 / 8 | 0 / 8 |
| serious Total, serious adverse events | 0 / 8 | 0 / 8 |
Outcome results
Primary
Waking Time - Re-establishment of the Gag Reflex.
The goal of the study is to determine whether caffeine speeds emergence from anesthesia. The time between terminating delivery of anesthetic and the subject starting to gag was measured. Anesthesia suppresses the gag reflex. Immediately after anesthetizing the test subject, a laryngeal mask airway (LMA) device was inserted into the test subject airway. After anesthesia was terminated and emergence from anesthesia was taking place, the gag reflex was re-established, and the LMA produced a gag response in all test subjects. This objective and unequivocal measurement constituted the emergence time for each subject. The emergence time was defined as the time between terminating the anesthesia and the test subject starting to gag.
Time frame: followed from the end of anesthesia to gag reflex, up to 2 hours
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Placebo | Waking Time - Re-establishment of the Gag Reflex. | 16.45 minutes | Standard Deviation 3.9 |
| Caffeine | Waking Time - Re-establishment of the Gag Reflex. | 9.57 minutes | Standard Deviation 5.1 |
p-value: 0.002paired t-test
Secondary
Bispectral Index
A bispectral index (BIS) measurement system was employed to measure depth of anesthesia. Using electrodes attached to the forehead to measure EEG, BIS outputs a dimensionless number between 0 and 100 that is proportional to the brain concentration of anesthetic and is thereby proportional to an individual's level of consciousness (Greenwald S, Chiang HH, Devlin P, Smith C, Sigl J, Chamoun N: The Bispectral Index (Bis2.0) as a Hypnosis Measure. Anesthesiology 1994; 81: A477-a477). When the test subjects arrive, prior to anesthesia, their BIS values are in the range of 95 - 99. That corresponds to an awake and alert state. During anesthesia, most subjects are in the range of 20 - 40, corresponding to an anesthetized state. As the anesthetic wears off, the BIS values rise until they are back in the 95 - 99 range that they were prior to anesthesia. In particular, we wished to determine whether BIS exhibited more rapid recovery after caffeine infusion as compared to saline (control).
Time frame: Continuous monitoring from start of anesthesia until discharge of test subject, up to 2 hours post-anesthesia.
Population: One subject was missing data at the last timepoint for the Placebo session
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Bispectral Index | 2 min post-anesthesia | 41.4 units on a scale | Standard Deviation 5.6 |
| Placebo | Bispectral Index | 10 minutes post-anesthesia | 62.5 units on a scale | Standard Deviation 8 |
| Placebo | Bispectral Index | 6 minutes post-anesthesia | 55.0 units on a scale | Standard Deviation 10.6 |
| Placebo | Bispectral Index | 12 minutes post-anesthesia | 62.9 units on a scale | Standard Deviation 11.5 |
| Placebo | Bispectral Index | 4 min post-anesthesia | 48.5 units on a scale | Standard Deviation 11.9 |
| Placebo | Bispectral Index | 14 minutes post-anesthesia | 62.6 units on a scale | Standard Deviation 10.7 |
| Placebo | Bispectral Index | 8 minutes post-anesthesia | 60.3 units on a scale | Standard Deviation 7.9 |
| Placebo | Bispectral Index | 16 minutes post-anesthesia | 69.1 units on a scale | Standard Deviation 14.2 |
| Placebo | Bispectral Index | 0 minutes post-anesthesia | 34.1 units on a scale | Standard Deviation 3.8 |
| Caffeine | Bispectral Index | 16 minutes post-anesthesia | 84.1 units on a scale | Standard Deviation 11.9 |
| Caffeine | Bispectral Index | 0 minutes post-anesthesia | 36.3 units on a scale | Standard Deviation 3.5 |
| Caffeine | Bispectral Index | 2 min post-anesthesia | 43.1 units on a scale | Standard Deviation 15.4 |
| Caffeine | Bispectral Index | 4 min post-anesthesia | 55.5 units on a scale | Standard Deviation 13.8 |
| Caffeine | Bispectral Index | 6 minutes post-anesthesia | 58.1 units on a scale | Standard Deviation 11.7 |
| Caffeine | Bispectral Index | 8 minutes post-anesthesia | 69.1 units on a scale | Standard Deviation 11.7 |
| Caffeine | Bispectral Index | 10 minutes post-anesthesia | 71.3 units on a scale | Standard Deviation 9.5 |
| Caffeine | Bispectral Index | 12 minutes post-anesthesia | 76.5 units on a scale | Standard Deviation 12.5 |
| Caffeine | Bispectral Index | 14 minutes post-anesthesia | 82.4 units on a scale | Standard Deviation 11.2 |
Secondary
Cognitive Test1 - Visual Analog Scale --- Feel Bad
Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. Fifteen minutes after terminating anesthesia each subject was asked to complete a series of psychomotor tests, if they were able. Otherwise the testing started at 30 minutes. The tests were repeated every 15 minutes. The first test, a visual analog scale (VAS) test consisted of two 100-mm lines, each labelled with of feel good or feel bad displayed on a computer screen. Test subjects were asked to rate how they currently felt by placing a cursor on each of the line (0=not at all, 100=extremely). The test repeated every 15 minutes.
Time frame: Test was given at 15, 30, 45, 60, 75, 90, 105 and 120 minutes after terminating anesthesia.
Population: Some participants could not be tested at the early timepoints due to not being fully awake etc.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 15 minutes post-anesthesia | 6.0 units on a scale | Standard Deviation 0 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 30 minutes post-anesthesia | 17.9 units on a scale | Standard Deviation 20.9 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 45 minutes post-anesthesia | 13.0 units on a scale | Standard Deviation 14.1 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 60 minutes post-anesthesia | 9.8 units on a scale | Standard Deviation 10.3 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 75 minutes post-anesthesia | 6.0 units on a scale | Standard Deviation 8.1 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 90 minutes post-anesthesia | 7.0 units on a scale | Standard Deviation 7.2 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 105 minutes post-anesthesia | 6.6 units on a scale | Standard Deviation 11 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 120 minutes post-anesthesia | 4.3 units on a scale | Standard Deviation 4.3 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 120 minutes post-anesthesia | 4.3 units on a scale | Standard Deviation 6.5 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 15 minutes post-anesthesia | 27.4 units on a scale | Standard Deviation 24.2 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 75 minutes post-anesthesia | 8.5 units on a scale | Standard Deviation 12 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 30 minutes post-anesthesia | 11.6 units on a scale | Standard Deviation 13.3 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 105 minutes post-anesthesia | 3.9 units on a scale | Standard Deviation 4.3 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 45 minutes post-anesthesia | 11.8 units on a scale | Standard Deviation 14.7 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 90 minutes post-anesthesia | 6.4 units on a scale | Standard Deviation 7.4 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Bad | 60 minutes post-anesthesia | 10.0 units on a scale | Standard Deviation 12.2 |
Secondary
Cognitive Test1 - Visual Analog Scale --- Feel Good
Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. Fifteen minutes after terminating anesthesia each subject was asked to complete a series of psychomotor tests, if they were able. Otherwise the testing started at 30 minutes. The tests were repeated every 15 minutes. The first test, a visual analog scale (VAS) test consisted of two 100-mm lines, each labelled with of feel good or feel bad displayed on a computer screen. Test subjects were asked to rate how they currently felt by placing a cursor on each of the line (0=not at all, 100=extremely). The test repeated every 15 minutes.
Time frame: Test was given at 15, 30, 45, 60, 75, 90, 105 and 120 minutes after terminating anesthesia.
Population: Some participants could not be tested at the early timepoints due to not being fully awake etc.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 15 minutes post-anesthesia | 29 units on a scale | Standard Deviation 0 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 30 minutes post-anesthesia | 48.1 units on a scale | Standard Deviation 29.5 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 45 minutes post-anesthesia | 50.9 units on a scale | Standard Deviation 29 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 60 minutes post-anesthesia | 62.8 units on a scale | Standard Deviation 26.5 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 75 minutes post-anesthesia | 60.0 units on a scale | Standard Deviation 28.2 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 90 minutes post-anesthesia | 61.5 units on a scale | Standard Deviation 26.7 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 105 minutes post-anesthesia | 66.3 units on a scale | Standard Deviation 24.1 |
| Placebo | Cognitive Test1 - Visual Analog Scale --- Feel Good | 120 minutes post-anesthesia | 66.0 units on a scale | Standard Deviation 25.1 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 120 minutes post-anesthesia | 66.8 units on a scale | Standard Deviation 27.7 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 15 minutes post-anesthesia | 54.8 units on a scale | Standard Deviation 22.4 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 75 minutes post-anesthesia | 59.3 units on a scale | Standard Deviation 25.9 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 30 minutes post-anesthesia | 50.3 units on a scale | Standard Deviation 25.4 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 105 minutes post-anesthesia | 61.9 units on a scale | Standard Deviation 24.3 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 45 minutes post-anesthesia | 58.1 units on a scale | Standard Deviation 26.5 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 90 minutes post-anesthesia | 59.5 units on a scale | Standard Deviation 25.7 |
| Caffeine | Cognitive Test1 - Visual Analog Scale --- Feel Good | 60 minutes post-anesthesia | 55.1 units on a scale | Standard Deviation 27.5 |
Secondary
Cognitive Test2 - Sternberg Test of Memory
Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. The test was first applied at 15 minutes following anesthesia, if the subject was awake and then repeated every 15 minutes. In the Sternberg Test of Memory (STM) participants were asked to memorize a string of numbers. Afterwards, a computer would flash a series of random numbers on the screen and the participant was asked whether the number on the computer screen was part of the earlier string or not. In three rounds, participants were given a string of 2, then 4, then 6 numbers. The latency until the subject answered the question was monitored and this is the data summarized here.
Time frame: Test was given at 15, 30, 45, 60 minutes after terminating anesthesia.
Population: Some participants could not be tested at the early timepoints due to not being fully awake etc.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Cognitive Test2 - Sternberg Test of Memory | 15 minutes post-anesthesia | 847 ms | Standard Deviation 0 |
| Placebo | Cognitive Test2 - Sternberg Test of Memory | 30 minutes post-anesthesia | 908.9 ms | Standard Deviation 146.9 |
| Placebo | Cognitive Test2 - Sternberg Test of Memory | 45 minutes post-anesthesia | 791.1 ms | Standard Deviation 99.6 |
| Placebo | Cognitive Test2 - Sternberg Test of Memory | 60 minutes post-anesthesia | 734.4 ms | Standard Deviation 100.1 |
| Caffeine | Cognitive Test2 - Sternberg Test of Memory | 60 minutes post-anesthesia | 733.5 ms | Standard Deviation 84.1 |
| Caffeine | Cognitive Test2 - Sternberg Test of Memory | 15 minutes post-anesthesia | 1001.4 ms | Standard Deviation 182.8 |
| Caffeine | Cognitive Test2 - Sternberg Test of Memory | 45 minutes post-anesthesia | 780.8 ms | Standard Deviation 127.7 |
| Caffeine | Cognitive Test2 - Sternberg Test of Memory | 30 minutes post-anesthesia | 853.7 ms | Standard Deviation 176 |
Secondary
Cognitive Test3 - Divided Attention Task
Normally patients receiving anesthesia exhibit significant cognitive problems for hours after anesthesia is terminated. The goal is to determine whether caffeine helps ameliorate the cognitive issues. The test was first applied at 15 minutes following anesthesia, if the subject was awake and then repeated every 15 minutes. In the Divided Attention Task (DAT), participants were asked to fly an airplane over the center of a winding road with a joystick and simultaneously press a button whenever targets randomly flashed on the screen. The computer program tracked the root mean squared (RMS) deviation of the plane from the center of the road and the latency for pressing the trigger when the target appeared.
Time frame: Test was given at 15, 30, 45, 60 minutes after terminating anesthesia.
Population: Some participants could not be tested at the early timepoints due to not being fully awake etc.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Cognitive Test3 - Divided Attention Task | 15 minutes post-anesthesia | 26.3 mm away from optimal | Standard Deviation 0 |
| Placebo | Cognitive Test3 - Divided Attention Task | 30 minutes post-anesthesia | 38.2 mm away from optimal | Standard Deviation 19.9 |
| Placebo | Cognitive Test3 - Divided Attention Task | 45 minutes post-anesthesia | 35.2 mm away from optimal | Standard Deviation 25.3 |
| Placebo | Cognitive Test3 - Divided Attention Task | 60 minutes post-anesthesia | 24.5 mm away from optimal | Standard Deviation 9.5 |
| Caffeine | Cognitive Test3 - Divided Attention Task | 60 minutes post-anesthesia | 23.4 mm away from optimal | Standard Deviation 6.4 |
| Caffeine | Cognitive Test3 - Divided Attention Task | 15 minutes post-anesthesia | 38.2 mm away from optimal | Standard Deviation 4.3 |
| Caffeine | Cognitive Test3 - Divided Attention Task | 45 minutes post-anesthesia | 29.1 mm away from optimal | Standard Deviation 13.3 |
| Caffeine | Cognitive Test3 - Divided Attention Task | 30 minutes post-anesthesia | 29.8 mm away from optimal | Standard Deviation 14 |
Secondary
Heart Rate
This measurement was made in order to determine whether caffeine altered heart rate in a deleterious manner.
Time frame: Continuous monitoring from start of anesthesia until discharge of test subject, up to 2 hours post-anesthesia.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Heart Rate | Pre-anesthesia | 79 beats per minute | Standard Deviation 13 |
| Placebo | Heart Rate | 5 minutes after anesthesia | 71 beats per minute | Standard Deviation 16 |
| Placebo | Heart Rate | 30 minutes after anesthesia | 79 beats per minute | Standard Deviation 7 |
| Placebo | Heart Rate | 60 minutes after anesthesia | 67 beats per minute | Standard Deviation 6 |
| Caffeine | Heart Rate | 60 minutes after anesthesia | 67 beats per minute | Standard Deviation 9 |
| Caffeine | Heart Rate | Pre-anesthesia | 75 beats per minute | Standard Deviation 11 |
| Caffeine | Heart Rate | 30 minutes after anesthesia | 75 beats per minute | Standard Deviation 9 |
| Caffeine | Heart Rate | 5 minutes after anesthesia | 66 beats per minute | Standard Deviation 10 |
Secondary
Mean Arterial Blood Pressure
This measurement was made in order to determine whether caffeine altered blood pressure in a deleterious manner.
Time frame: Continuous monitoring from start of anesthesia until discharge of test subject, up to 2 hours post-anesthesia.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Mean Arterial Blood Pressure | Pre-anesthesia | 89 mmHg | Standard Deviation 9 |
| Placebo | Mean Arterial Blood Pressure | 5 minutes after anesthesia | 72 mmHg | Standard Deviation 9 |
| Placebo | Mean Arterial Blood Pressure | 30 minutes after anesthesia | 94 mmHg | Standard Deviation 10 |
| Placebo | Mean Arterial Blood Pressure | 60 minutes after anesthesia | 96 mmHg | Standard Deviation 6 |
| Caffeine | Mean Arterial Blood Pressure | 60 minutes after anesthesia | 98 mmHg | Standard Deviation 6 |
| Caffeine | Mean Arterial Blood Pressure | Pre-anesthesia | 90 mmHg | Standard Deviation 7 |
| Caffeine | Mean Arterial Blood Pressure | 30 minutes after anesthesia | 98 mmHg | Standard Deviation 8 |
| Caffeine | Mean Arterial Blood Pressure | 5 minutes after anesthesia | 79 mmHg | Standard Deviation 15 |
Secondary
Minute Ventilation
The volume of gas inhaled or exhaled from a person's lungs per minute. We wished to determine whether caffeine altered minute ventilation.
Time frame: Continuous monitoring from time lma inserted until subject started to gag and it was removed, up to 2 hours post-anesthesia.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Minute Ventilation | Post-infusion | 6.2 L/minute | Standard Deviation 1.4 |
| Placebo | Minute Ventilation | Emergence | 7.5 L/minute | Standard Deviation 2.1 |
| Caffeine | Minute Ventilation | Post-infusion | 7.2 L/minute | Standard Deviation 1.1 |
| Caffeine | Minute Ventilation | Emergence | 8.5 L/minute | Standard Deviation 3.7 |