Cephalic Spread of Block With Head Down Tilt in Spinal Anaesthesia - A Randomised Controlled Study

Study Overview
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Brief Summary
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Subarachnoid block has become an established and reliable method of providing anaesthesia for lower abdominal and lower limb surgeries. Several factors determine the spread of local anaesthetic solutions in CSF. Among them, patient position is an important determining factor. Anesthesiologists give various degrees of head down tilt which they believe is both safe for the patient and will result in adequate level of block. Often these are arbitrarily done by the operator as most of the operation theatre tables are not equipped with any device to measure the accurate degree of tilt. As there is no agreement on the effect of Trendelenberg position on height of subarachnoid block, the current clinical study will be undertaken to estimate the effect of operation theatre table tilt at the time of lumbar puncture on the height of subarachnoid block.

Detailed Description
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Subarachnoid block has become an established and reliable method of providing anaesthesia for lower abdominal and lower limb surgeries. A definitive advantage that subarachnoid block provides is the profound nerve block that can be produced in a large part of the body by the relatively simple injection of a small amount of local anaesthetic. Twenty-five factors have been invoked as determinants of the spread of local anaesthetic solutions in CSF. Among them, patient position is an important determining factor. Operation theatre table tilts have been used to influence the spread of hyperbaric solution to ultimately influence the final height of the block. Studies have shown that a 10 degree head down tilt can result in cephalad spread of analgesia when compared to the horizontal group. So, in cases where the spinal block level was not high enough to perform a given surgery, the Trendelenburg position has been used to extend the level of the block. Hence, it is assumed that a higher level of block can be achieved with a smaller volume of the local anaesthetic agent, thus reducing the side effects. But others have noted that there was no statistically significant increase in the level of block even with 15 degree head down tilt. In spite of this, anesthesiologists give various degrees of head down tilt which they believe is both safe for the patient and will result in adequate level of block. Often these are arbitrarily done by the operator as most of the operation theatre tables are not equipped with any device to measure the accurate degree of tilt. An application called clinometer that utilizes the gyroscope sensor and determines the plane of the gadget in vertical as well as horizontal directions has been described. This application can be used to measure the exact degree of tilt given after sub arachnoid block. As there is no agreement on the effect of Trendelenberg position on height of subarachnoid block, the current clinical study will be undertaken to estimate the effect of operation theatre table tilt at the time of lumbar puncture on the height of subarachnoid block.

Official Title
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Cephalic Spread of Block With Head Down Tilt in Spinal Anaesthesia - A Randomised Controlled Study

Conditions
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Head-Down Tilt Following Spinal Anesthesia

Intervention / Treatment
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* Procedure: Group X - head low tilt
* Procedure: Group Y - head low tilt
* Procedure: Group C - neutral


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients belonging to ASA physical status I and II undergoing lower abdominal and lower limb surgeries under spinal anaesthesia Exclusion Criteria: Patient refusal contraindicated for spinal anaesthesia allergy to local anaesthetic agents used obesity (body mass index >29 kg/m2) Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

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
Interventional Model Description: Patients were randomly allocated to one of the 3 groups by closed envelope method
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Group C Control<br>spinal anaesthesia was given with table in neutral positon. Same position was maintained after spinal anaesthesia | Procedure: Group C - neutral<br>* spinal anaesthesia was given with table in neutral positon. Patient was maintained in supine position for 10 minutes following spinal anaesthesia<br>|
| Active Comparator: Group X<br>spinal anaesthesia was given with table in neutral positon. 10 degree head low position was maintained for 10 minutes following spinal | Procedure: Group X - head low tilt<br>* spinal anaesthesia was given with table in neutral positon. 10 degree head low position was maintained for 10 minutes following spinal anaesthesia<br>|
| Active Comparator: Group Y<br>the table was put in 10 degree head low position before proceeding to give spinal anaesthesia. Head low position was maintained for 10 minutes following spinal | Procedure: Group Y - head low tilt<br>* the table was put in 10 degree head low position before proceeding to give spinal anaesthesia. Head low position was maintained for 10 minutes following spinal<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximum height of block |  | from 5 minutes to 150 minutes after intrathecal injection | 
| Two segment regression time | time from injection of spinal drug to regression of the sensory block by two segments from the maximum | from 5 minutes to 150 minutes after intrathecal injection | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hypotension | drop in systolic blood pressure to less than 30% of baseline values or systolic blood pressure (SBP) below 90mmHg | every minute for 5 min after intrathecal drug administration, every 5 min till 30 min and thereafter every 10 minutes till 150 minutes after intrathecal injection | 
| Tachycardia | heart rate more than 100bpm or increase by more than 30% over baseline value. | every minute for 5 min after intrathecal drug administration, every 5 min till 30 min and thereafter every 10 minutes till 150 minutes after intrathecal injection. | 
| Bradycardia | heart rate less than 50bpm or decrease by more than 30% below baseline value. | every minute for 5 min after intrathecal drug administration, every 5 min till 30 min and thereafter every 10 minutes till 150 minutes after intrathecal injection | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anesthetics, Local, Head-Down Tilt, Anesthesia, Spinal, hypotension