Hypothermia
Conditions
Keywords
intraoperative warming, anesthesia, hypothermia, body temperature
Brief summary
Hypothermia is a common and serious complication during anesthesia and surgery. Anesthetic-induced hypothermia results from the inhibition of thermoregulatory control and exposure to cold operating room environment. Various warming methods, such as warm blankets, forced-air warmers and circulating water mattresses, are currently used to prevent and treat mild perioperative hypothermia. All are cutaneous approaches that rely on heating the peripheral tissues in order to increase the thermal core temperature. Application of cutaneous warming system blankets/pads are limited by location/extent of operative site; for example, in certain procedures such as laparatomies, reconstructive plastic surgery or orthopedic surgery, only a limited amount of skin surface is available for warming application. The Dynatherm vitalHEAT technology takes advantage of the body's natural thermoregulatory system to channel thermal energy to the body's core non-invasively at a rapid rate. The vital heat (vH2) system is designed to treat hypothermia during the peri-operative period through a combination of localized heat and vacuum application to one hand & forearm; this application 1) opens the arteriovenous anastamoses located in the palm of the hand and 2) conductively warms the extremity thus effectively warming the blood flow to the body's core. The vital heat vH2 system is a portable and compact warming device which provides a non-invasive approach to warming patients during surgery. The primary objective of this study is to determine if the Dynatherm Medical vitalHEAT (vH2) Temperature Management System is as effective as the forced-air warming Bair Hugger™ (Arizant Healthcare, Eden Prairie, MN) for maintenance of intraoperative body temperature in patients undergoing abdominal surgery under general anesthesia. The critical endpoints to be evaluated in making this determination are 1) % of subjects with an average intraoperative esophageal temperature of ≥ 36º C and 2) % of subjects with an initial post anesthesia care unit sublingual temperature of ≥ 36º C. Secondary objectives include 1) comparison of the core body temperatures @ 60 minutes post anesthesia induction, 2) comparison of temperature trends during surgery and 3) comparison of the subjects' post anesthesia care unit temperature trends and hypothermic symptoms such as shivering.
Interventions
DEVICEDynatherm Medical vitalHEAT Temperature Management System vH2
The vH2 system consists of a Control Unit containing the heating system and the vacuum generation pump which connects via an umbilical containing the fluid and vacuum tubing to the Warming Sleeve. The Control Unit also contains the user interface and alarm management systems. The disposable Warming Sleeve consists of a manifold attached to the warming pads and a polyurethane pouch (Vacuum Sleeve) that are placed over the patient's hand and forearm and secured with tape. The Warming Sleeve manifold contains connectors for the fluid and vacuum tubing contained in the umbilical.
DEVICEBair Hugger™ (Arizant Healthcare, Eden Prairie, MN)
The Bair Hugger system is the current standard of care at Tampa General Hospital. It consists of a Temperature Management Unit that contains the heating element, the air circulating motor and the temperature control mechanisms. This unit connects via a hose to the operating room blankets. The Bair Hugger technology relies on heated air convection. Warm air is circulated evenly through the air space in the specially designed blanket, warming the skin surface as well as any insulating blankets placed over the Bair Hugger blanket.
Sponsors
University of South Florida
Dynatherm Medical Inc.
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
* Patients undergoing elective open abdominal surgical procedures with an expected duration of 2 to 4 hours and requiring general anesthesia * American Society of Anesthesiologists(ASA) physical status I-III * Patient age: \> 18 years and \<80 years
Exclusion criteria
* Patient age: \< 18 years and \>80 years * Patients with break in skin integrity on the extremity selected as the application site * Patients with history of upper extremity peripheral vascular disease * Patients with history of allergic skin conditions of the upper extremities * Patients with history of bleeding disorders/coagulopathy * Patient with history of malignant hyperthermia * Patients who are pregnant * Patient unwilling or unable to give informed consent
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percent of Patients With an Average Intraoperative Temperature Greater Than or Equal to 36 Celcius | Intraoperative Period | — |
| Percent of Subjects With an Initial PACU Sublingual Temperature of ≥ 36º C. | Temp taken just prior to surgery | — |
| Percentage of Patients With a Post Operative Sublingual Temperature Above 36 Degrees Celcius | Upon entry to the post anesthesia care unit | Percent of subjects with an initial post anesthesia care unit sublingual temperature of ≥ 36º C |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Comparison of the Core Body Temperatures at 60 Minutes Post Anesthesia Induction,as Assessed by Esophageal Probe. | 60 minutes post anesthesia induction | Average core body temperature measured with an esophageal probe at 60 minutes post-induction |
| Average Intraoperative Esophageal Temperature | Intraoperative 0-70 minutes | Average esophageal temperature for the first 70 minutes of surgery following induction of anesthesia. |
| Median Post Anesthesia Care Unit Sublingual Temperature | Upon arrival to the post anesthesia care unit | — |
Countries
United States
Participant flow
Recruitment details
Subjects were recruited as they arrived for a scheduled surgical procedure at Tampa General Hospital. Potential subjects were addressed in a private pre-operative room. The investigators or study designee evaluated the patients for the study by reviewing the inclusion and exclusion criteria.
Participants by arm
| Arm | Count |
|---|---|
| vH2 System Group The vH2 system consists of a Control Unit containing the heating system and the vacuum generation pump which connects via an umbilical containing the fluid and vacuum tubing to the Warming Sleeve. The Control Unit also contains the user interface and alarm management systems. The disposable Warming Sleeve consists of a manifold attached to the warming pads and a polyurethane pouch (Vacuum Sleeve) that are placed over the patient's hand and forearm and secured with tape. The Warming Sleeve manifold contains connectors for the fluid and vacuum tubing contained in the umbilical. The vH2 System will be used for patient warming during these surgical procedures. Monitoring of core temperature via esophageal probe will be done for the purpose of data collection. | 21 |
| Control Group The Bair Hugger system is the current standard of care at TGH. It consists of a Temperature Management Unit that contains the heating element, the air circulating motor and the temperature control mechanisms. This unit connects via a hose to the operating room blankets. The Bair Hugger technology relies on heated air convection. Warm air is circulated evenly through the air space in the specially designed blanket, warming the skin surface as well as any insulating blankets placed over the Bair Hugger blanket. The Bair Hugger System is the site's current approach to patient warming during these surgical procedures. Monitoring of core temperature via esophageal probe will be done for the purpose of data collection. | 21 |
| Total | 42 |
Baseline characteristics
| Characteristic | Control Group | vH2 System Group | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 6 Participants | 4 Participants | 10 Participants |
| Age, Categorical Between 18 and 65 years | 15 Participants | 17 Participants | 32 Participants |
| Age Continuous | 46.5 years STANDARD_DEVIATION 14 | 51.1 years STANDARD_DEVIATION 18.3 | 48.7 years STANDARD_DEVIATION 16.5 |
| Region of Enrollment United States | 21 participants | 21 participants | 42 participants |
| Sex: Female, Male Female | 11 Participants | 10 Participants | 21 Participants |
| Sex: Female, Male Male | 10 Participants | 11 Participants | 21 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 21 | 0 / 21 |
| serious Total, serious adverse events | 0 / 21 | 0 / 21 |
Outcome results
Primary
Percentage of Patients With a Post Operative Sublingual Temperature Above 36 Degrees Celcius
Percent of subjects with an initial post anesthesia care unit sublingual temperature of ≥ 36º C
Time frame: Upon entry to the post anesthesia care unit
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| vH2 System Group | Percentage of Patients With a Post Operative Sublingual Temperature Above 36 Degrees Celcius | 95 Percentage of participants |
| Control Group | Percentage of Patients With a Post Operative Sublingual Temperature Above 36 Degrees Celcius | 100 Percentage of participants |
Primary
Percent of Patients With an Average Intraoperative Temperature Greater Than or Equal to 36 Celcius
Time frame: Intraoperative Period
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| vH2 System Group | Percent of Patients With an Average Intraoperative Temperature Greater Than or Equal to 36 Celcius | 56 percentage of participants |
| Control Group | Percent of Patients With an Average Intraoperative Temperature Greater Than or Equal to 36 Celcius | 90 percentage of participants |
p-value: 0.027Fisher Exact
Primary
Percent of Subjects With an Initial PACU Sublingual Temperature of ≥ 36º C.
Time frame: Temp taken just prior to surgery
Population: Per protocol, sample size calculations indicate that a total sample size of 42 patients will be necessary to evaluate the primary outcome at an adjusted alpha = 0.05 with 80% power.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| vH2 System Group | Percent of Subjects With an Initial PACU Sublingual Temperature of ≥ 36º C. | 95 Percentage of participants |
| Control Group | Percent of Subjects With an Initial PACU Sublingual Temperature of ≥ 36º C. | 100 Percentage of participants |
p-value: 1Fisher Exact
Secondary
Average Intraoperative Esophageal Temperature
Average esophageal temperature for the first 70 minutes of surgery following induction of anesthesia.
Time frame: Intraoperative 0-70 minutes
| Arm | Measure | Value (MEAN) |
|---|---|---|
| vH2 System Group | Average Intraoperative Esophageal Temperature | 36.3 Degrees Celcius |
| Control Group | Average Intraoperative Esophageal Temperature | 36.0 Degrees Celcius |
Secondary
Comparison of the Core Body Temperatures at 60 Minutes Post Anesthesia Induction,as Assessed by Esophageal Probe.
Average core body temperature measured with an esophageal probe at 60 minutes post-induction
Time frame: 60 minutes post anesthesia induction
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| vH2 System Group | Comparison of the Core Body Temperatures at 60 Minutes Post Anesthesia Induction,as Assessed by Esophageal Probe. | 36.4 degrees celcius | Standard Deviation 0.4 |
| Control Group | Comparison of the Core Body Temperatures at 60 Minutes Post Anesthesia Induction,as Assessed by Esophageal Probe. | 36.1 degrees celcius | Standard Deviation 0.5 |
p-value: 0.078t-test, 1 sided
Secondary
Median Post Anesthesia Care Unit Sublingual Temperature
Time frame: Upon arrival to the post anesthesia care unit
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| vH2 System Group | Median Post Anesthesia Care Unit Sublingual Temperature | 36.4 Degrees Celcius |
| Control Group | Median Post Anesthesia Care Unit Sublingual Temperature | 36.6 Degrees Celcius |