Comparison of Normothermia Maintenance Between Resistive Blanket and Forced Air Warming Systems in Renal Transplant Surgery
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ClinicalTrials.gov Identifier: NCT04776954 |
Recruitment Status :
Recruiting
First Posted : March 2, 2021
Last Update Posted : June 24, 2022
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Condition or disease | Intervention/treatment | Phase |
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Surgery Temperature Change, Body | Device: Forced Air Warming System Device: Resistive Blanket Warming System | Not Applicable |
The study will involve two arms: a resistive blanket warming system arm and a forced air warming system arm. Both devices will be set to warm the participant at a standard 41 degrees Celsius when the participant is to be rewarmed.
During the study, the forced air warming system (FAWS) will be placed on the (resistive blanket warming system (RBWS), with the participant laying on top of the forced air warming system. The arm components will be wrapped around the participant's arms to assist with patient positioning for surgery. Both the forced air and resistive blanket warming systems will be attached to their respective heating units before the participant is brought to the OR and transferred to the operating room table. After the needed standard monitors for surgery have been placed, general anesthesia will be induced and maintained with participant's hemodynamics and other vitals maintained per standard care (no additional measurements beyond standard of care which is recorded in EPIC). The certified registered nurse anesthetists (CRNA) will be involved in the placement of the blankets. Operating Room Nurse managers and CRNA's will be informed by research team regarding participant's involvement in the study.
Participant's core temperature will be measured with a nasopharyngeal temperature probe. Vital signs, including continuous blood pressure, heart rate, oxygen saturation, and end-tidal carbon dioxide, will be monitored and recorded in Epic as is routine with all anesthetics performed.
Standard anesthetic care of the participant will occur for the duration of the surgery. The participant will be randomized to either the FAWS or RBWS before arrival to the operating room. The participant's temperature will be monitored and recorded for the duration of surgery with the selected warming system. The primary outcome variable is the nasopharyngeal temperature as recorded at the end of the surgery.
Temperature measurement in the PACU will be standardized with skin temperature probes that will be placed on the forehead prior to leaving the operating room.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 130 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Basic Science |
Official Title: | Comparison of Normothermia Maintenance Between Resistive Blanket and Forced Air Warming Systems in Renal Transplant Surgery |
Actual Study Start Date : | September 27, 2021 |
Estimated Primary Completion Date : | December 31, 2022 |
Estimated Study Completion Date : | December 31, 2022 |

Arm | Intervention/treatment |
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Active Comparator: Forced Air Warming System
Participants in this arm will receive warming using a forced air warming system.
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Device: Forced Air Warming System
The forced air warming system has a heater unit that blows air through a conduit to an "air blanket" that inflates with forced air that circulates throughout the blanket, and exits through tiny perforations on the patient-side of that blanket. The heat primarily warms the subject through convective means. As the warmed air escapes through the perforations in the blanket, it creates an environment of continuously circulating warm air that is in contact with the skin. |
Active Comparator: Resistive Blanket Warming System
Participants in this arm will receive warming using a resistive blanket warming system.
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Device: Resistive Blanket Warming System
This blanket is equivalent to an operating-room-safe electric blanket. Through a power cord, a separate power source powers a semiconductor layer within the resistive blanket to generate heat. The heat primarily warms the subject by conductive warming through direct skin contact, and, secondarily, by warming the air around the participant in areas where there is no direct skin contact. |
- AUC of Temperature vs Time [ Time Frame: up to 5 hours ]
Outcome is reported as the Area Under Curve (AUC) of temperature vs time curve during hypothermia (core temperature less than 36 degrees Celcius) during the duration of surgery. Unit of measure is degrees Celsius per minute.
Time during surgery spent under 36 degrees Celsius through comparison of nasopharyngeal temperature, which is measured by placing a nasopharyngeal temperature probe 10 to 20 cm into the nare, between forced air warming system (FAWS) and resistive blanket warming system (RBWS).
- Minimum body temperature upon arrival in PACU [ Time Frame: up to 2 hours ]Outcome is reported as the minimum body temperature recorded upon arrival in post-anesthesia care unit (PACU).
- Maximum body temperature difference upon arrival in PACU [ Time Frame: up to 2 hours ]Outcome us reported as the maximum difference in body temperature upon arrival in post-anesthesia care unit (PACU).
- First and Last PACU Temperature [ Time Frame: at least 1 hour ]Outcome is reported as body temperature in degrees Celsius. The first temperature and last taken while the patient is in the post-anesthesia care unit (PACU) will be reported.
- Participants requiring rescue intervention [ Time Frame: up to 5 hours ]Outcome is reported as the number of participants in each arm who require rescue intervention, which is defined as the need to turn on a second, upper body warming blanket if body temperature is consistently below 35.5 degrees.

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Ages Eligible for Study: | 18 Years to 90 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Undergoing elective renal transplantation
Exclusion Criteria:
- Previous surgery involving organ transplantation or nephrectomy. These patients are at higher risk of blood loss, making temperature regulation subject to more variables outside our control.
- End stage renal disease with decreased or no urine output from normal. Bladder temperature will not be valid in these patients.
- Previous upper extremity amputations
- Ongoing sepsis or other infection
- Thyroid dysfunction
- Emergency surgery
- Refusal of consent to participate in study
- Pregnancy

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04776954
Contact: Cole Bennett, MD | 716-725-7975 | bennettc@umn.edu |
United States, Minnesota | |
University of Minnesota | Recruiting |
Minneapolis, Minnesota, United States, 55455 |
Principal Investigator: | Cole Bennett, MD | University of Minnesota |
Responsible Party: | University of Minnesota |
ClinicalTrials.gov Identifier: | NCT04776954 |
Other Study ID Numbers: |
ANES-2021-29543 |
First Posted: | March 2, 2021 Key Record Dates |
Last Update Posted: | June 24, 2022 |
Last Verified: | June 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | Yes |
Product Manufactured in and Exported from the U.S.: | No |
Body Temperature Changes |