Prevention of Perioperative Hypothermia in Patients Submitted to Transurethral Resection

Study Overview
=================
Brief Summary
-----------------
Hypothermia is a frequent perioperative complication. When the negative effects of anesthesia on temperature are aggravated by other factors, such as glycine infusion in transurethral resection, temperature can decrease even more. Preoperative warming prevents hypothermia, lowering the temperature gradient between core and peripheral compartments and reducing thermal redistribution. The most recent clinical practice guidelines advocate for active prewarming before induction of general anaesthesia since it is very effective in preventing perioperative hypothermia. However, the ideal warming time prior to the induction of anesthesia has long been investigated. This study aims to evaluate the optimal time period of preoperative forced-air warming to reduce the incidence of hypothermia at the end of surgery in patients submitted to transurethral resection. This is a clinical trial comparing different time periods of prewarming in patients submitted to undergo elective transurethral resection. We will compare different time periods: 0 minutes (control group), 15 minutes, 30 minutes and 45 minutes. 144 patients are going to be included in this study (36 patients in each group). Measurement of temperature will be performed using a tympanic thermometer. Patients will be followed throughout their hospital admission. Data will be recorded using a validated instrument and will be analysed using the statistics program R Core Team.

Detailed Description
-----------------
Maintaining patient's temperature above 36 grades Celsius throughout the perioperative period is challenging. Thus, it is essential to monitor temperature in order to be able to take measures to avoid the appearance of hypothermia. Once the temperature has decreased, its treatment is difficult since the application of heat to the body surface takes a long time to reach the core thermal compartment. Intraoperative warming alone cannot avoid postoperative hypothermia. The application of forced-air warming system during the preoperative period has been shown to be the most effective measure to prevent hypothermia and maintain intraoperative normothermia. However, it would not be efficient to provide a long-time prewarming in short-term surgical procedures. Thus, the ideal warming time prior to the induction of anesthesia has long been investigated. Due to the searching of optimal prewarming time and the lack of evidence about the efficiency of prewarming in patients submitted to transurethral resection, the conductance of this clinical trial is justified.

Official Title
-----------------
Prevention of Perioperative Hypothermia in Patients Submitted to Transurethral Resection

Conditions
-----------------
Hypothermia; Anesthesia, Perioperative/Postoperative Complications, Complication of Anesthesia, Temperature Change, Body, Anaesthesia Complication, Transurethral Resection Syndrome

Intervention / Treatment
-----------------
* Device: WarmTouch Model 5900, Covidien Ltd, Mansfield, USA


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients undergoing elective Transurethral resection under general or spinal anesthesia. Patients older tan 18 years old. American Society of Anesthesiologists physical status classification I - III. Absence of cognitive impairment. Written informed consent before enrollment. Exclusion Criteria: American Society of Anesthesiologists physical status classification I - III. Pregnancy. Active infection. Intake of antipyretics within 24 hours before surgery. Neuropathy. Thyroid disorders. Peripheral vascular disease. Skin lesions. History of hypersensitivity to skin contact devices.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: We will compare different time periods: 0 minutes (control group), 15 minutes, 30 minutes and 45 minutes. Sample size was authorized by IRB to be changed from 144 to 244 (61 patients per group) due to possible missing data.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br>Non-active prewarming. Patients will be actively warmed during the intraoperative period. Tympanic thermometer (Genius 2 Tympanic Thermometer and Base, Covidien Ltd, Mansfield, USA) will be used to measure the temperature throughout the perioperative period. | |
| Experimental: Prewarming during 15 minutes<br>Active Prewarming will be performed during 15 minutes, using a forced-air blanket (WarmTouch lower body blanket, Covidien Ltd, Mansfield, USA) over the whole body and connected to a forced-air warmer (WarmTouch Model 5900, Covidien Ltd, Mansfield, USA). Patients will be actively warmed during the intraoperative period. Tympanic thermometer (Genius 2 Tympanic Thermometer and Base, Covidien Ltd, Mansfield, USA) will be used to measure the temperature throughout the perioperative period. | Device: WarmTouch Model 5900, Covidien Ltd, Mansfield, USA<br>* Forced-air warming will be applied in the preanesthetic room during different time periods.<br>|
| Experimental: Prewarming during 30 minutes<br>Active Prewarming will be performed during 30 minutes, using a forced-air blanket (WarmTouch lower body blanket, Covidien Ltd, Mansfield, USA) over the whole body and connected to a forced-air warmer (WarmTouch Model 5900, Covidien Ltd, Mansfield, USA). Patients will be actively warmed during the intraoperative period. Tympanic thermometer (Genius 2 Tympanic Thermometer and Base, Covidien Ltd, Mansfield, USA) will be used to measure the temperature throughout the perioperative period. | Device: WarmTouch Model 5900, Covidien Ltd, Mansfield, USA<br>* Forced-air warming will be applied in the preanesthetic room during different time periods.<br>|
| Experimental: Prewarming during 45 minutes<br>Active Prewarming will be performed during 45 minutes, using a forced-air blanket (WarmTouch lower body blanket, Covidien Ltd, Mansfield, USA) over the whole body and connected to a forced-air warmer (WarmTouch Model 5900, Covidien Ltd, Mansfield, USA). Patients will be actively warmed during the intraoperative period. Tympanic thermometer (Genius 2 Tympanic Thermometer and Base, Covidien Ltd, Mansfield, USA) will be used to measure the temperature throughout the perioperative period. | Device: WarmTouch Model 5900, Covidien Ltd, Mansfield, USA<br>* Forced-air warming will be applied in the preanesthetic room during different time periods.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in Body Temperature among different treatment groups (using tympanic and esophageal thermometers) | To assess the effects of prewarming in preventing drop of body temperature of patients undergoing elective transurethral resection. | Throughout surgery, an average of 60 minutes. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length of stay in Post-Anesthetic Care Unit (in minutes) | To assess the effect of prewarming in the length of stay in the Post-Anesthetic Care Unit of patients undergoing elective transurethral resection. | Stay in Post-Anesthetic Care Unit, an average of 6 hours. | 
| Postoperative shivering (using a dichotomous scale: yes or no) | To assess the effect of prewarming in the prevalence of postoperative shivering of patients undergoing elective transurethral resection. | Immediate postoperative period, an average of 1 hour. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Prewarming, Tympanic temperature, Transurethral Resection