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Trial registered on ANZCTR


Registration number
ACTRN12612000812897
Ethics application status
Approved
Date submitted
30/07/2012
Date registered
2/08/2012
Date last updated
2/08/2012
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effects of anesthetic technique and ambient temperature on thermoregulation in lower extremity surgery
Scientific title
The effects of anesthetic technique and ambient temperature on thermoregulation in lower extremity surgery
Secondary ID [1] 280932 0
none
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
anesthesia 287024 0
thermoregulation 287025 0
Condition category
Condition code
Anaesthesiology 287353 287353 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
patients were divided into three groups according to their applied anesthesia technique: Group EA (epidural anesthesia, n=30) and Group FS (femoral sciatic block, n=30). Then, these groups were divided into two each based on the ambient temperature of the operating room, which was either 20-22 degrees C or 23-25 degrees C. The final distribution of the patients into four subgroups is as follows: Group EA I = patients undergoing epidural anesthesia (EA) (n=15) with a surgical room temperature (RT) of 20-22 degrees C, Group EA II = patients undergoing EA (n=15) with a surgical RT of 23-25 degrees C, Group FS I = patients undergoing femoral sciatic block (FS) (n=15) with a surgical RT of 20-22 degreesC, and Group FS II = patients undergoing FS (n=15) with a surgical RT of 23-25 degrees C.

After the skin was cleaned with antiseptic solution, the EA group patients were seated and locally anesthetized by 2 ml 2% lidocaine subcutaneous infiltration at the L4-5 level in the midline skin. Epidural anesthesia was performed by using a 16 G Touhy needle according to the loss of resistance technique. After reaching the epidural space, an 18 G epidural catheter was inserted through a Touhy needle and directed towards the head. After the absence of intravascular and intrathecal area was assessed by negative aspiration, the catheter tip was placed 3-4 cm within the epidural space. Three ml of 2% lidocaine was given as a test dose and waited for 5 minutes. After receiving a negative response to the test dose, 10-20 ml of 0.5% levobupivacaine and 50 micro g fentanyl was administered. Three L/min oxygen was given to patients with a facemask. The level of sensory block was checked in 5-minute intervals by the Pinprick test, and additional doses were administered as needed. Patients with the sensory block degree up to T10 were included in the study, but patients who developed higher levels of sensory block were excluded.
Patients in Group FS were applied a sciatic block by using the classical Labat technique. After patients were placed at a lateral decubitus position, the posterior superior iliac spine and trochanter major were localized and marked. The vertical medial line was drawn in the middle of the line connecting those two points and the injection point was determined to be 4 cm along this line. After the area was cleaned with antiseptic solutions and covered, 1 ml of 2% lidocaine was injected subcutaneously to create local anesthesia at the injection point. The block, together with the nerve stimulator (Stimuplex HNS 11, Braun Freiburg, Germany), was made with a 150 mm block needle entering vertical to the skin. The initial current of the nerve stimulator was set to 1.5-2 mA, and after the plantar or dorsal flexion was obtained, the current was reduced to 0.3-0.5 mA. After a negative aspiration test was observed, 25 ml of 0.375% levobupivacaine solution was injected. The patient was laid in the supine position for the femoral block and the inguinal ligament was determined by drawing a line connecting the to the anterior superior spine iliac and lateral corner of simfisis pubis. An injection point was marked 2 cm lateral to the pulse of the femoral artery and 2 cm distal to the inguinal ligament line. The area was cleaned with an antiseptic solution and wraped with a sterile. An eighty-mm-long nerve block needle was connected to the nerve stimulator and was forwarded in the cranial direction parallel to the femoral artery at an angle 30-40° to the skin surface. The needle was forwarded until quadriceps femoris muscle contractions and patella movements were seen. Then, the stimulation current intensity was reduced to 0.3-0.5 mA and was followed by observance of negative aspiration, after which a 20 ml 0.375% levobupivacaine solution was injected.
Intervention code [1] 285366 0
Treatment: Other
Comparator / control treatment
Group GA (general anesthesia, n = 30), was divided into two subgroups based on the ambient temperature of opearting room, which was either 20-22 degrees C or 23-25 degrees C. Group GA I = patients undergoing general anesthesia (GA) (n=15) with a surgical room temperature (RT) of 20-22 degrees C, Group GA II = patients undergoing GA (n=15) with a surgical RT of 23-25 degrees C.
After GA group patients received preoxygenation with 100% O2, intravenous induction of anesthesia was obtained with 3-6 mg/kg sodium thiopental 0.1mg/kg vecuronium bromide and 2 mg/kg fentanyl. After endotracheal intubation, anesthesia was maintained with 5-6% desflurane in 50% N2O-50% O2. Respiration was continued mechanically and was adjusted to 30 to 40 mmHg ETCO2. In addition, to partially humidify and heat inhaled gases, a disposable humidifier was added to the breathing circuit. When necessary, patients were given additional doses of fentanyl and vecuronium bromide. To remove the residual muscle relaxant effects during recovery from anesthesia, 0.04 mg/kg neostigmine, and when required, 0.01 mg/kg intravenous atropine was used. When laryngeal reflexes and adequate spontaneous breathing returned, the patients were extubated.
Control group
Active

Outcomes
Primary outcome [1] 287623 0
tympanic temperature
(tympanic temperature measured via infrared thermometer)
Timepoint [1] 287623 0
before anesthesia induction, in 5-minute intervals after the induction of anesthesia, and in arrival to PACU
Primary outcome [2] 287624 0
mean skin temperature [0.3 (Tchest+Tarm) + 0.2 (Tthigh+Tcalf)]
(peripheral temperatures measured via anesthesia machine thermometers)
Timepoint [2] 287624 0
before anesthesia induction, in 5-minute intervals after the induction of anesthesia
Primary outcome [3] 287625 0
mean body temperature [0.64 x Tcentral + 0.36 x Tskin]
(tympanic temperature measured via infrared thermometer, but peripheral temperatures measured via anesthesia machine thermometers)
Timepoint [3] 287625 0
before anesthesia induction, in 5-minute intervals after the induction of anesthesia
Secondary outcome [1] 298553 0
Shivering score (0: no shivering, 1: presence of one or more of such findings as piloerection, peripheral vasoconstriction, and peripheral cyanosis without muscle movement, 2: presence of muscle activity observable in single muscle group, 3: presence of muscle activity in more than one muscle group, 4: presence of significant muscle activity observed in the whole body)
Timepoint [1] 298553 0
before anesthesia induction, in 5-minute intervals after the induction of anesthesia

Eligibility
Key inclusion criteria
The study was included 90 male patients aged between 18-60 years whose physical status was in the American Society of Anesthesiologists (ASA) I-II risk group and were scheduled for lower extremity surgery. In all cases, to avoid errors in body temperature measurements arising from the diurnal rhythm, body temperature measurements were taken in the morning between 08:30 and 13:00 hours.
Minimum age
18 Years
Maximum age
60 Years
Sex
Males
Can healthy volunteers participate?
No
Key exclusion criteria
Patients with inflammatory diseases, diabetes mellitus, muscle disease, hypo/hyperthyroidism, cardiac, hepatic and renal diseases, Parkinson disease, Reynold syndrome, a history of using drugs that are known to affect body temperature (Beta-blockers, calcium channel blockers, clonidine, steroids, anti-epileptic, non-steroidal anti-inflammatory drugs, benzodiazepine), vertebral column anatomical disorder, bleeding diathesis, anticoagulant use, infection at the region of procedure, neurological deficits, drug and alcohol addiction, obesity, and those with allergies to local anesthetics were excluded from the study. In addition, patients whose surgery was shorter than 60 minutes and longer than 180 minutes and those surgeries where a tourniquet was used were also excluded from the study. Patients having a greater than 30% change in hemodynamic parameters during the surgery, those who needed to use a vasopressor or vasodilator, and those who required a blood transfusion were excluded from the study as well.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Phase 4
Type of endpoint/s
Safety
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
1/04/2011
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
90
Accrual to date
Final
Recruitment outside Australia
Country [1] 4446 0
Turkey
State/province [1] 4446 0

Funding & Sponsors
Funding source category [1] 285715 0
Self funded/Unfunded
Name [1] 285715 0
Country [1] 285715 0
Primary sponsor type
Individual
Name
Ayse Belin OZER
Address
Department of Anesthesiology and Reanimation, Firat University, 23119, Elazig
Country
Turkey
Secondary sponsor category [1] 284545 0
None
Name [1] 284545 0
Address [1] 284545 0
Country [1] 284545 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 287722 0
Firat University Medical School Ethical Evaluation Commission Chairman
Ethics committee address [1] 287722 0
Firat University Medical School Ethical Evaluation Commission Chairman
Firat University
23119,Elazig
Ethics committee country [1] 287722 0
Turkey
Date submitted for ethics approval [1] 287722 0
07/02/2011
Approval date [1] 287722 0
10/03/2011
Ethics approval number [1] 287722 0

Summary
Brief summary
Background: Hypothermia is the most common thermoregulatory disorder encountered during anesthetic methods and it can cause complications. The aim of our study is to determine the effects of anesthetic technique and ambient temperature on thermoregulation in patients undergoing lower extremity surgery.
Methods: Our study included 90 male patients aged 18-60 years within the American Society of Anesthesiologists (ASA) I-II risk group who were scheduled for lower extremity surgery. Patients were randomly divided into three groups according to the applied anesthetic technique: general anesthesia (GA), epidural anesthesia (EA), and femoral-sciatic block (FS). These groups were then divided into subgroups according to room temperature: the temperature for group I was 20-22 degrees C and the temperature for group II was 23-25 degrees C. Therefore, we labeled the groups as follows: Group GA I, GA II, EA I, EA II, FS I and FS II. Probes for measuring the tympanic membrane and peripheral temperature were placed in patients, and their mean skin temperature (MST) and mean body temperature (MBT) were assessed immediately before the induction of anesthesia and 5, 10, 15, 20, 30, 45, 60, 90 and 120 minutes after the induction of anesthesia. Once patients were in the post anesthesia care unit, the tympanic membrane, axillary temperature, shivering, visual analog scale (VAS) and nausea-vomiting scores were recorded.
Results: With the method of anesthesia, tympanic and mean body temperature (MBT) decreased, while mean skin temperature (MSK) increased in all of the patients. There was no significant difference in tympanic temperatures between either of the room temperature or anesthetic method groups. MST was lower in the GA I group than in the GA II group at 5, 10, 15, 20, 60 and 90 minutes, while the MBT was significantly lower at the basal level (p<0.05). MST at 5 minutes was significantly lower in the GA I group as compared to the FS I group (p<0.05). The shivering score in the GA I group and the VAS scores in the GA I and GA II groups were significantly higher than those of the other groups (p<0.05). During the postoperative period, there was no significant difference in tympanic and axillary temperature or nausea and vomiting scores.
Conclusions: There were no significant differences between applied anesthetic techniques, and room temperature only affected the patient group undergoing general anesthesia.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 34502 0
Address 34502 0
Country 34502 0
Phone 34502 0
Fax 34502 0
Email 34502 0
Contact person for public queries
Name 17749 0
Ayse Belin OZER
Address 17749 0
Firat University Medicine Faculty
Anesthesiology and Reanimation Department
23119, Elazig
Country 17749 0
Turkey
Phone 17749 0
+90 424 533 4478924
Fax 17749 0
+90 424 2388096
Email 17749 0
[email protected]
Contact person for scientific queries
Name 8677 0
Ayse Belin OZER
Address 8677 0
Firat University Medicine Faculty
Anesthesiology and Reanimation Department
23119, Elazig
Country 8677 0
Turkey
Phone 8677 0
+90 424 533 4478924
Fax 8677 0
+ 90 424 2388096
Email 8677 0
[email protected]

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