Major Surgery Under General Anesthesia
Conditions
Keywords
Thoracic Surgery, Thoracic surgery, Video assisted, Open Abdominal Surgery, Anesthesia, General
Brief summary
The purpose of this study is to determine: 1. the effect of ambient temperature on the rate of core temperature change from 1 to 3 hours after induction of anesthesia (linear phase of the hypothermia curve) in major operations lasting at least a couple of hours and 2. whether the relationship between ambient temperature and rate of core temperature change is different for patients who are or are not warmed with forced-air.
Detailed description
Each patient will be randomly assigned to ambient temperature of 19°C, 21°C, or 23°C. Using a factorial approach, patients will also be randomly assigned to passive insulation or forced-air warming, stratified by the three types of surgery listed below. Group allocation will be based on computer generated codes (randomly permuted block sizes) prepared by Department of OUTCOMES RESEARCH statisticians using SAS statistical software. Allocation of consented patients to designated ambient temperature and forced-air vs. passive insulation will be via a web site that will be accessed by investigators in Bejing about 90 minutes before surgery. Patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping. Patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface. A lower-body cover (about 91 by 221 cm) will be positioned so the lower end of the forced-air segments extend from the ankles upward for the entire length of the cover in thoracic and abdominal cases. The cover's foot drape will extend over the feet, and in turn be covered by the surgical drape. An upper-body forced-air cover will similarly be applied for patients having hip arthroplasties. The forced-air cover will be connected to a Bair Hugger blower and #635 covers set to high (≈43°C). Ambient temperature will be adjusted to the designated temperature about an hour before a patient enters the operating room and adjusted as necessary to maintain the designated temperature throughout surgery. General anesthesia will be induced as per usual clinical routine. Neuraxial (epidural or spinal) and other regional blocks are permitted. Any patients whose core temperature decreases to less than 34.5°C will be actively warmed with forced air and the ambient temperature increases to the extent practical.
Interventions
OTHERAmbient Temperature 19°C
Ambient Temperature 19°C
OTHERAmbient Temperature 21°C
Ambient Temperature 21°C
OTHERAmbient Temperature 23°C
Ambient Temperature 23°C
DEVICEForced-air cover (Bair hugger 63500, 3M)
Patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface.
OTHERPassive insulation
Patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping.
Sponsors
The Cleveland Clinic
Peking Union Medical College Hospital
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
SUPPORTIVE_CARE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Adults scheduled for major open thoracic surgery or video assist thoracic surgery or major abdominal surgery under general anesthesia expected to last at least two hours
Exclusion criteria
* Special risk for bleeding or myocardial infarction (as determined by the attending anesthesiologist) * Patients who would otherwise have been actively warmed
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Rate of Core Temperature Change | from 1 to 3 hours after induction of anesthesia | Rate of core temperature change from 1 to 3 hours after induction of anesthesia (°C/hour ) linear mixed-effects model to assess the effects of ambient temperature, forced-air warming and their interaction on the rate of core temperature change during 1 to 3h after induction |
Countries
China
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Ambient Temp 19°C & Passive Insulation Ambient Temperature 19°C and Passive Insulation: patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping.
Ambient Temperature 19°C: Ambient Temperature 19°C
Passive insulation: Patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping. | 48 |
| Ambient Temp 19°C & Forced-air Warming Ambient Temperature 19°C and Forced-air Warming: patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface.
Ambient Temperature 19°C: Ambient Temperature 19°C
Forced-air cover (Bair hugger 63500, 3M): Patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface. | 50 |
| Ambient Temp 21°C & Passive Insulation Ambient Temperature 21°C and Passive Insulation: patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping.
Ambient Temperature 21°C: Ambient Temperature 21°C
Passive insulation: Patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping. | 49 |
| Ambient Temp 21°C & Forced-air Warming Ambient Temperature 21°C and Forced-air Warming: patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface.
Ambient Temperature 21°C: Ambient Temperature 21°C
Forced-air cover (Bair hugger 63500, 3M): Patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface. | 50 |
| Ambient Temp 23°C & Passive Insulation Ambient Temperature 23°C and Passive Insulation: patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping.
Ambient Temperature 23°C: Ambient Temperature 23°C
Passive insulation: Patients assigned to passive insulation will be covered as usual with a cotton gown and single layer of cloth surgical draping. | 47 |
| Ambient Temp 23°C & Forced-air Warming Ambient Temperature 23°C and Forced-air Warming: patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface.
Ambient Temperature 23°C: Ambient Temperature 23°C
Forced-air cover (Bair hugger 63500, 3M): Patients assigned to forced-air warming will also be covered with a gown and surgical drapes, but a forced-air cover (Bair hugger 63500, 3M) will be inserted between the gown and the skin surface. | 48 |
| Total | 292 |
Baseline characteristics
| Characteristic | Ambient Temp 19°C & Passive Insulation | Ambient Temp 19°C & Forced-air Warming | Ambient Temp 21°C & Passive Insulation | Ambient Temp 21°C & Forced-air Warming | Ambient Temp 23°C & Passive Insulation | Ambient Temp 23°C & Forced-air Warming | Total |
|---|---|---|---|---|---|---|---|
| Age, Continuous | 50 years STANDARD_DEVIATION 12 | 54 years STANDARD_DEVIATION 12 | 54 years STANDARD_DEVIATION 13 | 57 years STANDARD_DEVIATION 11 | 57 years STANDARD_DEVIATION 11 | 54 years STANDARD_DEVIATION 12 | 54 years STANDARD_DEVIATION 12 |
| Sex: Female, Male Female | 29 Participants | 27 Participants | 24 Participants | 18 Participants | 22 Participants | 24 Participants | 144 Participants |
| Sex: Female, Male Male | 19 Participants | 23 Participants | 25 Participants | 32 Participants | 25 Participants | 24 Participants | 148 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk | EG005 affected / at risk |
|---|---|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 48 | 0 / 50 | 0 / 49 | 0 / 50 | 0 / 47 | 0 / 48 |
| other Total, other adverse events | 1 / 48 | 1 / 50 | 1 / 49 | 1 / 50 | 1 / 47 | 2 / 48 |
| serious Total, serious adverse events | 0 / 48 | 0 / 50 | 0 / 49 | 0 / 50 | 0 / 47 | 0 / 48 |
Outcome results
Primary
Rate of Core Temperature Change
Rate of core temperature change from 1 to 3 hours after induction of anesthesia (°C/hour ) linear mixed-effects model to assess the effects of ambient temperature, forced-air warming and their interaction on the rate of core temperature change during 1 to 3h after induction
Time frame: from 1 to 3 hours after induction of anesthesia
Population: We plotted the mean core temperatures at 10-minute intervals. The trend of core temperature in each of the six groups between 1 to 3 hours was roughly linear. We thus used the slope (change in °C/hour) to characterize the rate sat which intraoperative core temperature changed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Ambient Temp 19°C & Passive Insulation | Rate of Core Temperature Change | -0.18 degree C | Standard Deviation 0.03 |
| Ambient Temp 19°C & Forced-air Warming | Rate of Core Temperature Change | 0.05 degree C | Standard Deviation 0.03 |
| Ambient Temp 21°C & Passive Insulation | Rate of Core Temperature Change | -0.06 degree C | Standard Deviation 0.03 |
| Ambient Temp 21°C & Forced-air Warming | Rate of Core Temperature Change | 0.07 degree C | Standard Deviation 0.03 |
| Ambient Temp 23°C & Passive Insulation | Rate of Core Temperature Change | -0.05 degree C | Standard Deviation 0.03 |
| Ambient Temp 23°C & Forced-air Warming | Rate of Core Temperature Change | 0.02 degree C | Standard Deviation 0.03 |
p-value: <0.05mixed-effects model