Selective Subarachnoid Anesthesia. Comparison of Hyperbaric Bupivacaine and Hyperbaric Prilocaine

Study Overview
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Brief Summary
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Selective spinal anesthesia is widely used for ambulatory surgery. Unilateral spinal anesthesia is a suitable option for ambulatory anesthesia as it is efficient and effective. Lidocaine has been the well-known choice for this procedure. However, it is associated to transient neurologic symptoms (TNS). Different anesthetic strategies for this procedure have been performed, for example, the use of small doses of long-acting agents and the use of additives such as opioids. The ideal local anesthetic should be lidocaine-like without risk of transient neurologic symptoms. We design and plan a randomised clinical trial to show if hyperbaric prilocaine 2% would be an alternative.

Official Title
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Selective Subarachnoid Anesthesia. Comparison of Hyperbaric Bupivacaine and Hyperbaric Prilocaine in Knee Arthroscopy and Inguinal Hernia Repair in Ambulatory Surgery

Conditions
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Knee Arthroscopy (for Diagnostic or Therapy), Inguinal Hernia Repair (Not Urgent)

Intervention / Treatment
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* Drug: Hyperbaric Prilocaine 1%
* Drug: Hyperbaric bupivacaine 0.5%


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with a scheduled knee arthroscopy Patients with a scheduled inguinal hernioplasty Exclusion Criteria: Patient refusal to regional anesthesia American Society of Anesthesiologists score risk equal or greater than 4 Body mass index greater than 32 Coagulopathy Cutaneous infection at injection site

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Hyperbaric prilocaine 1%<br>Solution for injection. Intradural use. In order to obtain Prilocaine 1% we charge a syringe with 2 mL Prilocaine 2%, and we add 1 mL Saline solution (0.9%) and 1 mL Glucose solution (33%). Administer 3 mL of syringe contains in two minutes. | Drug: Hyperbaric Prilocaine 1%<br>* Selective spinal anesthesia was performed on induction-block area and patient was transferred to the assigned operating room where another anesthesiologist (blinded for the arm) began to evaluate the blocking. Neither the nurse, surgeon nor the anesthesiologist involved in the patient evaluation knew the allocation group.<br>|
| Active Comparator: Hyperbaric Bupivacaine 0.5%<br>Solution for injection. Intradural use. Charge a syringe with 1 mL of Bupivacaine (0.5%) and administer it in a minute. | Drug: Hyperbaric bupivacaine 0.5%<br>* Selective spinal anesthesia was performed on induction-block area and patient was transferred to the assigned operating room where another anesthesiologist (blinded for the arm) began to evaluate the blocking. Neither the nurse, surgeon nor the anesthesiologist involved in the patient evaluation knew the allocation group.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length of stay in post-operative care unit (in minutes) | Time in minutes from closing the surgical incision until to having criteria for discharge to home. | Participants will be followed an average of 6 hours from surgical incision closure to accomplish discharge criteria to go home | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Level of motor blocking | Assessed by Bromage score who ranges from Complete block (unable to move feet or knees, score 1) to Able to perform partial knee bend (score 6 who means nil block). | At surgical incision and at 60 minutes after anesthesia | 
| Fast-track (by-pass recovery area) | Number (and percentage) of patients in each arm that can be transferred directly from the operating room to postsurgical ward. A minimal score of 12 (on modified Aldrete's scoring system with no score <1 in any individual category) would be required for a patient to be fast-tracked. | Participants will be assessed when surgical incision is closed with surgical staples | 
| Peak sensory block level | The sensory block level was determined pricking dermatomes with a pin from down to up. | One minute before surgical incision | 
| Transient neurological symptoms | Researchers surveyed if appears pain originated in gluteal region and radiating to both lower extremities following patients by phone. | At hospital discharge (an average of 8 hours after admission), and at home at 24, 48 and 72 hours after surgery |