Hypothermia Following AnesthesiaNCT03191214
Impact of Forced Air Warming on Perioperative Thermodynamics
An observational study of Hypothermia Following Anesthesia, run by University College, London at 1 site in United Kingdom.
Trial summary
The purpose of the study is to assess the temperature changes that take place throughout the body in a real world setting, when a patient is given general anaesthesia. Specifically we will investigate the movement of body heat from the core to the peripheries at the beginning of surgery. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Hypothermia Following Anesthesia
- What is being tested?
- Intraoperative Forced Air Warming
- Type of treatment
- Medical device
- How many people
- 24 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 21 Jul 2017to 15 Sep 2017
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Elective surgical patients
Who may be able to join
- Male \& Female patients, from 18 - 80 years old, undergoing surgery requiring general anaesthesia, who are deemed to have capacity to give informed consent and have done so in writing prior to commencement of surgery.
- The surgeries include :
- brief surgical procedures of >15 minutes requiring general for whom no warming devices are being employed
- surgical >30 minutes procedures in which forced air warming, is being used
Who cannot join
- Patients who do not adequately understand verbal explanations or written information given in English.
- Patients not possessive of capacity to give informed consent. Patients who have not given consent.
- Patients with :
- Peripheral vascular disease
- BMI >30
- Aortic aneurysms
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- Amputations
- Patients with a history of:
- Thyroid disease
- Dysautonomia
- Malignant hyperthermia
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University College London Hospital
London, NW1 2BU
Michael Mythen, MB BS, 020 3447 2810
About this study
Official title: An Observational Thermography Study of the Core-peripheral Temperature Gradient as a Function of Vascular Resistance During the Redistribution Phase Following the Induction of General Anaesthesia in Warmed and Non-warmed Patients
The purpose of the study is to assess the temperature changes that take place throughout the body in a real world setting, when a patient is given general anaesthesia. Specifically we will investigate the movement of body heat from the core to the peripheries at the beginning of surgery. This will be measures with a series of temperature sensors and infrared thermography
Read the detailed description
Intra-operative hypothermia increases the risk of a wide range of post operative complications; wound infection, damage to heart muscle, and an increased length of hospital stay.
A range of technologies exist for maintaining the temperature of patients undergoing surgical procedures. Yet despite the frequent use of forced air warming devices, a significant reduction in core temperature can occur in the first 60 minutes of some major surgeries.
This is an Observational Cross-Sectional Study, investigating patients undergoing elective surgery in two groups Group 1: Patients undergoing brief surgical procedures of >15 minutes for whom no warming devices are being employed.
Group 2: Patients undergoing surgical procedures in which forced air warming, is being used Potential participants will first be approached by medical staff at their pre-operative assessment clinic. They will be screened for exclusion criteria before being given a participant information sheet, which will be explained to them. They will be invited to contact the researcher if they are interested in participating in the study.
On arrival in hospital the day of their surgery, the patients will be met by their anaesthetist and a researcher who will provide any further information required about the study, and consent will be taken.
Following receipt of informed consent, patients will be involved from 30 minutes before their surgery begins, until the end of their surgery.
The null hypothesis is that there is no difference in the rate of flow of heat from the core to the peripheries between patients who receive warming during surgery, and those who do not. As it would be unethical to randomise a patient to not receive warming, we have designed an observational study to compare patients who are warmed / not warmed as part of their standard care. Patients undergoing surgery <30 minutes long are not routinely warmed during surgery.
Potential participants will be informed of the study at the pre-operative assessment clinic in the weeks preceding surgery. Posters will be located in the clinic rooms and relevant areas, and subjects will be given information by the clinic staff to read prior to their surgery.
Participants will be admitted to hospital the evening prior, or the morning of surgery, whereupon they will undergo standard admission processes, including pre-operative assessment by the anaesthetist assigned to that list. The anaesthetist and researcher will then explain the study again, reiterating the potential risks and benefits of the study to the patient themselves, and to the population as a whole. Written consent will be sought at this point.
Participants will be weighed and four measurements will be taken, comprising : arm length, leg length, trunk length and maximum abdominal width. Participants will stand onto a bioimpedance machine, which will quantify their body fat and body water percentage.
30 minutes before their operation, skin temperature sensors will be placed on the patient's forehead, forearm, finger, hip, calf and toe. An additional SpotOn temperature sensor, placed on the forehead will be used to non invasively measure core temperature.
Measurement of blood pressure, cardiac output and systemic vascular resistance will be obtained by a finger cuff connected to a Nexin Noninvasive cardiac output monitor. These measurements describe the action of the heart and blood vessels. At the end of each surgery the data recorded on this device will be transferred via an encrypted USB key onto a data acquisition laptop.
Temperature measurements from the seven of sensors will taken at 5 second intervals onto a data acquisition laptop.
At 15 minutes intervals Infra red thermography images will be taken from a FLIR a320 device. This equipment will be mounted on a raised boom above the surgeons, in a sterile sleeve. This will not be held over the patient at any point, and will be moved away from the patient between measurements.
Once the surgery has ended, and the patient has been transferred to the recovery area, all temperature sensors will be removed and the patient will exit the trial.
A sample size of 24 patients will be recruited to quantify the effect of warming.
- Conditions
- Hypothermia Following Anesthesia
- Being tested
- Intraoperative Forced Air Warming
- Keywords
- Infra-red thermography
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intraoperative Forced Air WarmingDevice
As part of their standard care, patients undergoing surgery >30 min in duration will receive forced air warming in the form of a Bair Hugger. This is a blanket covering their upper torso and arms into which warm air is blown.
| Study group | Role | What they receive |
|---|---|---|
| No Warming | Patients undergoing brief surgical procedures of >15 minutes for whom no warming devices are being employed. | |
| Forced Air Warming | Patients undergoing surgical procedures in which forced air warming, is being used Receives: Device: Intraoperative Forced Air Warming |
What is being measured
The primary outcome is the main question the study is designed to answer.
The change in core - peripheral temperature gradient
This will be calculated as the sum of, the increase in peripheral temperature and the decrease in core temperature, between 0 and 25 minutes from the induction of anaesthesia.
Peripheral temperature will be determined by segmental thermal analysis of thermography data, calibrated against skin temperature sensors.
Measured: At 25 minutes following induction of anaesthesia
Secondary outcomes (2)
Peripheral to core heat transfer due to warming
The increase in core temperature at 120 minutes compared to 60 minutes, as a proportion of the increase in temperature induced in the peripheries being warmed, over the same time period.
Measured: Between 60 minutes and 120 minutes following induction of anaesthesia
Change in temperature gradient as a function of time & systemic vascular resistance
Changes in the core peripheral temperature gradient (detailed in the 1º outcome) will be fitted as a function of time and systemic vascular resistance. The coefficients of this function will be compared between the two groups
Measured: For the first 25 minutes following induction of anaesthesia
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Jun 2017
- Study start21 Jul 2017 (estimated)
- Primary completion15 Sep 2017 (estimated)
- Study completion15 Sep 2017 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hypothermia Following AnesthesiaStudies of the same condition, open and under way.
- More trials run by University College, LondonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University College, London
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Fintan Hughes, Study director, Univeristy College London Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03191214
- Sponsor's protocol ID
- 228666
- Status last verified
- Jun 2017
- First submitted
- 13 Jun 2017
- Last updated
- 19 Jun 2017
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Jun 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Observational Thermography Study of the Core-peripheral Temperature Gradient as a Function of Vascular Resistance During the Redistribution Phase Following the Induction of General Anaesthesia in Warmed and Non-warmed Patients
- ClinicalTrials.gov ID
- NCT03191214
- Acronym / sponsor ID
- 228666
- Conditions
- Hypothermia Following Anesthesia
- Keywords
- Infra-red thermography
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- University College, LondonUniversity, hospital or other
- Study start
- 21 Jul 2017 (estimated)
- Primary completion
- 15 Sep 2017 (estimated)
- Study completion
- 15 Sep 2017 (estimated)
- First posted
- 19 Jun 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the study is to assess the temperature changes that take place throughout the body in a real world setting, when a patient is given general anaesthesia. Specifically we will investigate the movement of body heat from the core to the peripheries at the beginning of surgery. This will be measures with a series of temperature sensors and infrared thermography
Detailed description
Intra-operative hypothermia increases the risk of a wide range of post operative complications; wound infection, damage to heart muscle, and an increased length of hospital stay.
A range of technologies exist for maintaining the temperature of patients undergoing surgical procedures. Yet despite the frequent use of forced air warming devices, a significant reduction in core temperature can occur in the first 60 minutes of some major surgeries.
This is an Observational Cross-Sectional Study, investigating patients undergoing elective surgery in two groups Group 1: Patients undergoing brief surgical procedures of >15 minutes for whom no warming devices are being employed.
Group 2: Patients undergoing surgical procedures in which forced air warming, is being used Potential participants will first be approached by medical staff at their pre-operative assessment clinic. They will be screened for exclusion criteria before being given a participant information sheet, which will be explained to them. They will be invited to contact the researcher if they are interested in participating in the study.
On arrival in hospital the day of their surgery, the patients will be met by their anaesthetist and a researcher who will provide any further information required about the study, and consent will be taken.
Following receipt of informed consent, patients will be involved from 30 minutes before their surgery begins, until the end of their surgery.
The null hypothesis is that there is no difference in the rate of flow of heat from the core to the peripheries between patients who receive warming during surgery, and those who do not. As it would be unethical to randomise a patient to not receive warming, we have designed an observational study to compare patients who are warmed / not warmed as part of their standard care. Patients undergoing surgery <30 minutes long are not routinely warmed during surgery.
Potential participants will be informed of the study at the pre-operative assessment clinic in the weeks preceding surgery. Posters will be located in the clinic rooms and relevant areas, and subjects will be given information by the clinic staff to read prior to their surgery.
Participants will be admitted to hospital the evening prior, or the morning of surgery, whereupon they will undergo standard admission processes, including pre-operative assessment by the anaesthetist assigned to that list. The anaesthetist and researcher will then explain the study again, reiterating the potential risks and benefits of the study to the patient themselves, and to the population as a whole. Written consent will be sought at this point.
Participants will be weighed and four measurements will be taken, comprising : arm length, leg length, trunk length and maximum abdominal width. Participants will stand onto a bioimpedance machine, which will quantify their body fat and body water percentage.
30 minutes before their operation, skin temperature sensors will be placed on the patient's forehead, forearm, finger, hip, calf and toe. An additional SpotOn temperature sensor, placed on the forehead will be used to non invasively measure core temperature.
Measurement of blood pressure, cardiac output and systemic vascular resistance will be obtained by a finger cuff connected to a Nexin Noninvasive cardiac output monitor. These measurements describe the action of the heart and blood vessels. At the end of each surgery the data recorded on this device will be transferred via an encrypted USB key onto a data acquisition laptop.
Temperature measurements from the seven of sensors will taken at 5 second intervals onto a data acquisition laptop.
At 15 minutes intervals Infra red thermography images will be taken from a FLIR a320 device. This equipment will be mounted on a raised boom above the surgeons, in a sterile sleeve. This will not be held over the patient at any point, and will be moved away from the patient between measurements.
Once the surgery has ended, and the patient has been transferred to the recovery area, all temperature sensors will be removed and the patient will exit the trial.
A sample size of 24 patients will be recruited to quantify the effect of warming.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| No Warming | – | –Patients undergoing brief surgical procedures of >15 minutes for whom no warming devices are being employed. |
| Forced Air Warming | – | Device: Intraoperative Forced Air WarmingPatients undergoing surgical procedures in which forced air warming, is being used |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Elective surgical patients
Key inclusion criteria (4 listed)
- Male \& Female patients, from 18 - 80 years old, undergoing surgery requiring general anaesthesia, who are deemed to have capacity to give informed consent and have done so in writing prior to commencement of surgery.
- brief surgical procedures of >15 minutes requiring general for whom no warming devices are being employed
- surgical >30 minutes procedures in which forced air warming, is being used
Key exclusion criteria (11 listed)
- Patients who do not adequately understand verbal explanations or written information given in English.
- Patients not possessive of capacity to give informed consent. Patients who have not given consent.
- Peripheral vascular disease
- BMI >30
- Aortic aneurysms
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Intraoperative Forced Air WarmingAs part of their standard care, patients undergoing surgery >30 min in duration will receive forced air warming in the form of a Bair Hugger. This is a blanket covering their upper torso and arms into which warm air is blown. | Device | Forced Air Warming |
Primary outcome
The change in core - peripheral temperature gradient
Time frame: At 25 minutes following induction of anaesthesia
This will be calculated as the sum of, the increase in peripheral temperature and the decrease in core temperature, between 0 and 25 minutes from the induction of anaesthesia. Peripheral temperature will be determined by segmental thermal analysis of thermography data, calibrated against skin temperature sensors.
2 secondary outcomes
Peripheral to core heat transfer due to warming
Time frame: Between 60 minutes and 120 minutes following induction of anaesthesia
Change in temperature gradient as a function of time & systemic vascular resistance
Time frame: For the first 25 minutes following induction of anaesthesia
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Jun 2017.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Fintan Hughes study director
Univeristy College London Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Hypothermia Following Anesthesia, run by University College, London at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 19 Jun 2017. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Fintan Hughes (+44 7731403686, Fintan.hughes@ucl.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The change in core - peripheral temperature gradient (time frame: At 25 minutes following induction of anaesthesia). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Jun 2017.