Minimal Effective Dose of Hyperbaric Spinal Bupivacaine for Saddle Block

• Sponsor: Imam Abdulrahman Bin Faisal University (Other)
• Overall Status: Completed
• CT.gov ID: NCT02299167
• Collaborator: (none)
• Enrollment: 35
• Arm: 1
• Duration (Months): 9

Study Details

Study Description

Brief Summary

The optimal anesthetic technique would provide excellent operating conditions, rapid recovery, early discharge, no postoperative side effects, and high patient's satisfaction. In addition to increasing the quality and decreasing the costs of the anesthetic services (1). Selective spinal anesthesia (SSA) -spinal block with minimal effective doses for a specific type of surgery - has become very popular technique) 2(for some orthopedic and gynecological surgeries [3-9].

Saddle anesthesia is a SSA directs a small bolus of hyperbaric local anesthetic, towards S4-S5 and coccygeal nerve roots (11), and is commonly utilized for perianal surgeries (11-14). Hyperbaric bupivacaine has been safely, replaced hyperbaric Lidocaine for saddle block (11, 12).

Although Saddle blocks at different low doses of hyperbaric bupivacaine (1.5- 4 mg) have been used previously for mi¬nor perianal surgeries (11, 13, 14), the optimal effective dose has yet to be determined.

The objective of this study is to determine the minimal effective dose of hyperbaric spinal bupivacaine required to induce a reliable and satisfactory saddle block for perianal surgeries (using a modified Dixon's up-and-down method.

Condition or Disease	Intervention/Treatment	Phase
Perianal Surgery	Drug: Dixon's up-and-down method	Phase 3

Detailed Description

Following approval of the Research and Ethics Committee of the University of Dammam and written informed consent, patients with American Society of Anesthesiologists physical Status I and II, aged 20-55 years, scheduled for outpatient elective perianal surgery in the lithotomy position ( hemorrhoidectomy, fistulectomy), were prospectively enrolled in this study. Patients unwilling to participate, those with contraindications to regional anesthesia, morbid obesity, bleeding disorders, mental health problems or language barriers, taking psychotropic or analgesic medication, or a known history of allergic reactions to amide local anesthetics, were excluded from the study.

Actually, 35 patients were enrolled. However; after they have signed the informed consent; 7 patients were excluded because they have received analgesics in the morning of surgery, and 4 patients refused to receive the saddle block on the operating room. So actually 24 patients out of 35 participants underwent intervention

All patients were fasted for over 6 hours and were premedicated with 0.2 mg/kg oral diazepam 60 min before spinal anesthesia.

In the operating room (OR), an intravenous (IV) 18-20G catheter was placed, and standard monitoring [electrocardiogram (ECG), heart rate (HR), oxygen saturation (SpO2), and noninvasive blood pressure (NIBP)] were started.

Under aseptic conditions, the dural puncture was performed by staff-grade anesthesiologists, using a standard midline approach in the sitting position at the L3-L4 or L4-L5 intervertebral space, using a 25-gauge Whitacre needle with its orifice directed caudally. A predetermined small dose of hyperbaric bupivacaine (Marcaine Spinal Heavy; Astra Zeneca, Lund, Sweden) which was prepared in1 mL tuberculin syringe was injected. All patients remained in the sitting position for 10 min. the patient was asked if he/she perceived any change in motor power.

If not, the patient was allowed to position him/herself without aid for surgery in the lithotomy position. Immediately before surgery, the sacral level of sensory block was tested using a long surgical toothless clamp gently applied radially, starting from the anal orifice, in different diagonal directions.

The motor block was tested by a modified Bromage scale (0 = no motor block, 1 = able to flex the ankle and bend knees, 2 = able to flex ankle, and 3 = full motor block).

A successful block was defined as one that was sufficient to proceed with the surgery without any supplementation (intravenous analgesic, local anesthetic infiltration, or general anesthesia).

The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16).

The first patient was tested at a dose 1.5 mg bupivacaine, if the patient responded with a failed block then the next patient received an increment of 0.5 mg bupivacaine, if the patient responded with a successful block, then the next patient received a decrement of 0.5 mg bupivacaine.

The research continued until the investigators obtained seven crossover midpoints. The initial starting dose of 1.5 mg hyperbaric bupivacaine of the first patient was selected from the findings of Wassef R et al. who demonstrated adequate anesthesia for short perianal surgery with the use of 1.5 mg spinal hyperbaric bupivacaine.

Bupivacaine was prepared immediately before injection by an independent anesthesiologist and was administered by a second anesthesiologist. Block assessment and clinical follow-up of the patients was also performed by a third anesthesiologist.

The following data were recorded; Patient demographics, duration of anesthesia and surgery, level of sensory and motor block immediately before surgery, at the end of the surgery, and every 30 minutes until resolution of the block. NIBP and HR were documented every 5 minutes in the OR and PACU. Also Times to ambulation, first voiding time, and time to home discharge were recorded. Patient's and surgeon's satisfaction were evaluated with a 4-point score (0=poor, 1=good, 2=very good, 3= excellent). Patients were followed by phone call to note down any possible postoperative complication (postdural puncture headache, TNS or backache) at day 1 postoperatively and 10 days later. The time of the dural puncture was used as the primary starting point of assessment.

Study Design

• Study Type: Interventional
• Actual Enrollment: 35 participants
• Allocation: N/A
• Intervention Model: Single Group Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: The Minimal Effective Dose of Hyperbaric Spinal Bupivacaine for Successful Reliable Saddle Block for Minor Perianal Surgeries
• Study Start Date: Jan 1, 2014
• Actual Primary Completion Date: Sep 1, 2014
• Actual Study Completion Date: Oct 1, 2014

Arms and Interventions

Arm

Intervention/Treatment

Experimental: Saddle block The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method

Drug: Dixon's up-and-down method; using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.

Outcome Measures

Primary Outcome Measures

1. Minimal Effective Dose of Hyperbaric Bupivacaine [10 min after dural puncture]

   the minimal effective dose of hyperbaric bupivacaine using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.

Secondary Outcome Measures

1. Sacral Level of Sensory Block [every 30 min until complete regression of the block (approximately 90 min)]

   The level of sensory block was tested using a long surgical toothless clamp gently applied radially, starting from the anal orifice, in different diagonal directions

2. Motor Block Score as Assessed Using the Bromage Scale [every 30 min until Time to ambulation (approximately 2 hours)]

   The motor block was tested by a modified Bromage scale (0 = no motor block, 1 = able to flex the ankle and bend knees, 2 = able to flex ankle, and 3 = full motor block). A successful block was defined as one that was sufficient to proceed with the surgery without any supplementation (intravenous analgesic, local anesthetic infiltration, or general anesthesia).

3. Patient's Satisfactions [24 hours after surgery]

   Patient's satisfactions were evaluated with a 4-point satisfaction score (0=poor satisfaction, 1=good satisfaction 2=very good satisfaction, 3= excellent satisfaction

4. Surgeon's Satisfactions [24 hours after procedure]

   Surgeon's satisfactions were evaluated with a 4-point satisfaction score (0=poor satisfaction, 1=good satisfaction 2=very good satisfaction, 3= excellent satisfaction

Eligibility Criteria

Criteria

• Ages Eligible for Study: 20 Years to 55 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• American Society of Anesthesiologists physical Status I and II patients.

• Scheduled for outpatient elective perianal surgery.

Exclusion Criteria:

• Patients unwilling to participate.

• Contraindications to regional anesthesia.

• Morbid obesity.

• Bleeding disorders.

• Mental health problems.

• Language barrier.

• Taking psychotropic or analgesic medication.

• History of allergic reactions to amide local anesthetics.

Contacts and Locations

Locations

No locations specified.

Sponsors and Collaborators

• Imam Abdulrahman Bin Faisal University

Investigators

• Principal Investigator: Roshdi Al Metwalli, MD, Associate Professor at Anesthesiology Dept

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Imam Abdulrahman Bin Faisal University
• ClinicalTrials.gov Identifier: NCT02299167
• Other Study ID Numbers: ANE-2014-1-23
• First Posted: Nov 24, 2014
• Last Update Posted: Nov 24, 2020
• Last Verified: Sep 1, 2020

• Keywords provided by Imam Abdulrahman Bin Faisal University: Perianal surgery; hyperbaric bupivacaine; saddle block

Study Results

Participant Flow

Recruitment Details	Four independent anesthetists were assigned for the study from January 2014.one to select patients in the anesthesia clinic, the 2nd to prepare the studied drug in the OR, the 3rd one to inject the drug and the 4th one was to collect the data
Pre-assignment Detail	35 patients were enrolled However; after they have signed the consent. 7 patients were excluded because they have received analgesics in the morning of surgery. and 4 patients refused the saddle block in the operating room. So actually 24 patients out of 35 participants underwent intervention. That has been already specified in the protocol

Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Period Title: Overall Study
STARTED	35
Dural Puncture	24
Success Rate	24
Adverse Effects	24
COMPLETED	24
NOT COMPLETED	11

Baseline Characteristics

Arm/Group Title	Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Overall Participants	24
Age (Count of Participants)
<=18 years	0 0%
Between 18 and 65 years	24 100%
>=65 years	0 0%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	33.71 (10.24)
Sex: Female, Male (Count of Participants)
Female	9 37.5%
Male	15 62.5%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	0 0%
Asian	24 100%
Native Hawaiian or Other Pacific Islander	0 0%
Black or African American	0 0%
White	0 0%
More than one race	0 0%
Unknown or Not Reported	0 0%
Region of Enrollment (Count of Participants)
Saudi Arabia	24 100%

Outcome Measures

1. Primary Outcome

Title	Minimal Effective Dose of Hyperbaric Bupivacaine
Description	the minimal effective dose of hyperbaric bupivacaine using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Time Frame	10 min after dural puncture

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Measure Participants	24
Mean (95% Confidence Interval) [milligrams]	1.9

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Single Group Study / Saddle Block
	Comments	Descriptive statistics were considered to calculate the mathematic mean (SD) of demographic, surgical, and other postoperative continuous data and to calculate the median (range) of sensory and motor block levels, as well as the degree of patient and surgeon satisfaction
	Type of Statistical Test	Other
	Comments	The ED50% of spinal bupivacaine was estimated using a modified Dixon's up-and-down method
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean (95% CI) of effective dose in 90% (
	Estimated Value	1.9
	Confidence Interval	(2-Sided) 95%; 1.7 to 2.1
	Parameter Dispersion	Type: Value:
	Estimation Comments	The ED50% of spinal bupivacaine was estimated using a modified Dixon's up-and-down method

2. Secondary Outcome

Title	Sacral Level of Sensory Block
Description	The level of sensory block was tested using a long surgical toothless clamp gently applied radially, starting from the anal orifice, in different diagonal directions
Time Frame	every 30 min until complete regression of the block (approximately 90 min)

Outcome Measure Data

Analysis Population Description

Immediately before surgery S4 (S3-S4) At conclusion of surgery S4 (S3-S4) Maximum blocked dermatome S4 (S3-S4)

Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Measure Participants	12
Maximum blocked dermatome	4
At conclusion of surgery	4
Immediately before surgery	4

3. Secondary Outcome

Title	Motor Block Score as Assessed Using the Bromage Scale
Description	The motor block was tested by a modified Bromage scale (0 = no motor block, 1 = able to flex the ankle and bend knees, 2 = able to flex ankle, and 3 = full motor block). A successful block was defined as one that was sufficient to proceed with the surgery without any supplementation (intravenous analgesic, local anesthetic infiltration, or general anesthesia).
Time Frame	every 30 min until Time to ambulation (approximately 2 hours)

Outcome Measure Data

Analysis Population Description

The block characteristics for patients with successful block (12 patients)

Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Measure Participants	12
Immediately before surgery	0
At conclusion of surgery 0 Aided patient positioni	0

4. Secondary Outcome

Title	Patient's Satisfactions
Description	Patient's satisfactions were evaluated with a 4-point satisfaction score (0=poor satisfaction, 1=good satisfaction 2=very good satisfaction, 3= excellent satisfaction
Time Frame	24 hours after surgery

Outcome Measure Data

Analysis Population Description

All patient with successful block were satisfied

Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Measure Participants	12
Median (Full Range) [score on a scale]	3

5. Secondary Outcome

Title	Surgeon's Satisfactions
Description	Surgeon's satisfactions were evaluated with a 4-point satisfaction score (0=poor satisfaction, 1=good satisfaction 2=very good satisfaction, 3= excellent satisfaction
Time Frame	24 hours after procedure

Outcome Measure Data

Analysis Population Description

All surgeon who operated on the patient with successful block (12 patients ) were satisfied

Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method Dixon's up-and-down method: using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if patient responded with failed block then the next patient received an increment of 0.5mg bupivacaine, if patient responded with successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
Measure Participants	12
Median (Full Range) [score on a scale]	3

Adverse Events

Time Frame	24 hours
Adverse Event Reporting Description	Postoperative complications PDPH 0 (0-0) Urinary retention 0 (0-0) backache 0 (0-0)
Arm/Group Title	Single Group Study / Saddle Block
Arm/Group Description	The dose of bupivacaine given to each patient was determined by the response of the previously tested patient using a modified Dixon's up-and-down method (using 0.5 mg as a step size) (16). The first patient was tested at a dose 1.5 mg bupivacaine, if the patient responded with a failed block then the next patient received an increment of 0.5mg bupivacaine, if the patient responded with a successful block, then the next patient received a decrement of 0.5mg bupivacaine. The research continued until we obtained seven crossover midpoints.
All Cause Mortality
	Single Group Study / Saddle Block
	Affected / at Risk (%)	# Events
Total	0/24 (0%)
Serious Adverse Events
	Single Group Study / Saddle Block
	Affected / at Risk (%)	# Events
Total	0/24 (0%)
Other (Not Including Serious) Adverse Events
	Single Group Study / Saddle Block
	Affected / at Risk (%)	# Events
Total	0/24 (0%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.