Changes in Cerebral Blood Flow (CBF) in Prone and Sitting Position Before and After GSP-block and Before and After Epidural Blood-patch: A Substudy of NCT03652714

Study Overview
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Brief Summary
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The purpose of this optional sub-study to GSPB-2018 (NCT03652714) is to evaluate the changes in cerebral blood flow (CBF) under different conditions to understand if postdural puncture headache is caused by changes in the cerebral blood flow and if treatment normalises that change.

Official Title
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Changes in Cerebral Blood Flow (CBF) in Prone and Sitting Position Before and After GSP-block and Before and After Epidural Blood-patch: A Substudy of NCT03652714

Conditions
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Postdural Puncture Headache, Sphenopalatine Ganglion Block

Intervention / Treatment
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* Procedure: Ganglion sphenopalatine block with local anesthetic administered on study GSPB-2018
* Procedure: Ganglion sphenopalatine block with placebo administered on study GSPB-2018


Participation Criteria
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Eligibility Criteria
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Study Population: Subjects who have consented to participate in GSPB-2018 will be approached for participation in this sub-study. Subjects who have consented to participate in GSPB-2018 are not required to participate in this sub-study. Inclusion Criteria: Age > 18 years Patients with postdural puncture headache defined as moderate to severe postural headache (VAS >= 30mm) after lumbar puncture or accidental dural puncture during epidural insertion with an onset within 3 days following the puncture. Lack of headache remission within 1 day after dural puncture and after treatment with fluids, caffeine and paracetamol Patients who have given their written informed consent for participation in the study and substudy after fully understanding the protocol content and limitations. Exclusion Criteria: Patients who cannot cooperate to the study Patients who does not understand or speak Danish Allergy to the drugs used in the study Has taken opioids within 12 hours prior to intervention No possible transcranial window on transcranial doppler. If not possible to find a useable window to get measurement the patient will be excluded and replaced with another patient.

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: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Local anesthetic<br> | Procedure: Ganglion sphenopalatine block with local anesthetic administered on study GSPB-2018<br>* Block performed with bilaterally inserted q-tips with 1:1 mixture of lidocaine 40mg/ml and ropivacaine 5mg/mL as per GSPB-2018.<br>|
| Placebo Comparator: Isotonic NaCl<br> | Procedure: Ganglion sphenopalatine block with placebo administered on study GSPB-2018<br>* Block performed with bilaterally inserted q-tips with isotone NaCl as per GSPB-2018.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Cerebral Blood Flow velcity (CBF) in supine versus upright position compared to effect of treatment. | Change in mean, minimum and maximum Cerebral Blood Flow velcity in cm/sec (CBF) in supine versus upright position compared to effect of treatment. | <1h before and 1 hour after each intervention | 
| Comparison of paint rating (0-100 on a visual analogue scale, VAS) and Cerebral Blood Flow velocity (CBF) before and after each intervention. | Pain intensity measured with a pain rating (0-100mm on a visual analogue scale, VAS) in supine position and as worst experienced pain after the patient has been upright for 30 seconds or the worst experienced pain while attempting to stand if the rating has to be interrupted. Cerebral Blood Flow velocity (CBF) measured as mean blood flow in cm/sec. | <1h before and 1 hour after each intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Cerebral Blood Flow velocity (CBF) in supine position before and after interventions. | Changes in mean, minimum and maximum Cerebral Blood Flow velocity in cm/sec (CBF) before and after treatment. | <1h before and 1 hour after each intervention |