Core Temperature Variations During Midazolam vs Propofol Sedation for Neuraxial Anesthesia

Study Overview
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Brief Summary
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The present study is a pilot study aiming to compare the variation in core temperature (measured through the non-invasive device Spot-OnTM3MTM) in patients submitted to neuraxial anesthesia for orthopedic procedures, during sedation with midazolam vs propofol.

Detailed Description
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In this study the investigators will select 20 patients scheduled for orthopedic surgery of the knee or foot with neuraxial anesthesia (subarachnoid or sequential blocks). Sedation for these procedures with midazolam or propofol is daily practice in the investigators' department. So the patients will be randomized, through the envelope method, in 2 groups with 10 patients each: midazolam group and propofol group. In the midazolam group the investigators will administer 0,05mg/kg of midazolam, being 2/3 administered before the neuraxial block and 1/3 after. In the propofol group the investigators will administer 0,033mg/kg of midazolam before the neuraxial block, and immediately after installation of the block the investigators will start a propofol target-controlled infusion (TCI) pump (Schnider model) with an effect concentration set at 1mcg/mL. This pump will be turned off at the end of the surgery. The neuraxial block will be performed inside the operating room and preferentially in lateral decubitus. The choice of drug and dosage used for the block will be left to the anesthesiologist, to mimetize day-to-day practice. The limit dermatome of sensory block will be noted. The investigators will administer to every patient: cefazolin 2g iv bolus, ketorolac 30 mg iv bolus, pantoprazole 40 mg iv bolus, paracetamol 1g iv perfusion (initiated 30 minutes before the end of surgery). Central temperature will be monitored with the SpotOnTM3MTM device from entering till leaving the operating room, through a sensor placed in the patient's forehead. Room temperature will be kept at 17 degrees Celsius (ºC). Patients will be warmed with a underbody forced-air blanket (BairHuggerTM3MTM) set at 38ºC and maximal flow, initiated after performing the neuraxial block and stopped right before leaving the operating room. Data will be analyzed with the Statistical Package for the Social Sciences (SPSS) program.

Official Title
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Core Temperature Variations During Midazolam vs Propofol Sedation for Neuraxial Anesthesia

Conditions
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Body Temperature Changes, Anesthesia

Intervention / Treatment
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* Drug: Midazolam
* Drug: Propofol
* Drug: Standard
* Device: SpotOn


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Scheduled for orthopedic surgery of the foot or knee Indication to neuraxial anesthesia Surgery duration > 30 minutes Exclusion Criteria: Preference for deep sedation Preference for no sedation Kidney failure Hepatic failure No signed informed consent

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Midazolam Group<br>In the midazolam group the investigators will administer 0,05mg/kg of midazolam, being 2/3 administered before the neuraxial block and 1/3 after. | Drug: Midazolam<br>* The investigators will administer 0,05mg/kg of midazolam, being 2/3 administered before the neuraxial block and 1/3 after.<br>* Other names: A;Drug: Standard<br>* The investigators will administer to every patient: cefazolin 2g iv bolus, ketorolac 30 mg iv bolus, pantoprazole 40 mg iv bolus, paracetamol 1g iv perfusion (initiated 30 minutes before the end of surgery).<br>Device: SpotOn<br>* Central temperature will be monitored with the SpotOnTM3MTM device from entering till leaving the operating room, through a sensor placed in the patient's forehead<br>|
| Active Comparator: Propofol group<br>In the propofol group the investigators will administer 0,033mg/kg of midazolam before the neuraxial block, and immediately after installation of the block the investigators will start a propofol TCI pump (Schnider model) with an effect concentration set at 1mcg/mL. This pump will be turned off at the end of the surgery. | Drug: Propofol<br>* The investigators will administer 0,033mg/kg of midazolam before the neuraxial block, and immediately after installation of the block the investigators will start a propofol TCI pump (Schnider model) with an effect concentration set at 1mcg/mL. This pump will be turned off at the end of the surgery.<br>* Other names: B;Drug: Standard<br>* The investigators will administer to every patient: cefazolin 2g iv bolus, ketorolac 30 mg iv bolus, pantoprazole 40 mg iv bolus, paracetamol 1g iv perfusion (initiated 30 minutes before the end of surgery).<br>Device: SpotOn<br>* Central temperature will be monitored with the SpotOnTM3MTM device from entering till leaving the operating room, through a sensor placed in the patient's forehead<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean temperature | Comparison between the mean temperature in the two groups | From entering the operating room up to cutaneous closure, an expected average of 1 to 1.5 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Level of sensory block, T1-12/L1-5, assessed by a blunted needle | Top dermatome of sensory block, evaluated with a blunt needle | From 5 to 10 minutes after the performance of the neuraxial block |