Post-dural puncture headache (PDPH) is a common complication in post-partum patients, with an incidence of 0.5–2% following spinal anaesthesia. Despite advancements in design and needle size, PDPH remains a common complication in female patients, particularly those pregnant and young, with low-body mass index, dilutional anemia, and neuraxial anaesthesia preference for caesarean sections. Treatment options include: conventional therapies, epidural blood patch (EBP), and sphenopalatine ganglion block (SPG) block. SPG block is a non-invasive, superficial method for pain relief while dexmedetomidine nebulization targets α2-adrenergic receptors to produce sedation, reduce anxiety, and provide pain relief. Dexmedetomidine can be administered via inhalational routes for various purposes, including premedication, sedation, and postoperative analgesia. The present study aims to test this hypothesis using transcranial Doppler (TCD) to evaluate the effect of Sphenopalatine Ganglion Block (SPGB) and nebulized Dexmedetomidine on cerebral hemodynamics.

    Primary objective:

1.    Comparison of Numerical Rating Scale (NRS) for pain at 1 hour in Sphenopalatine Ganglion (SPG) Block and Nebulized dexmedetomidine groups after intervention.

Secondary objectives

(Includes comparison between patients receiving SPG block and Nebulized dexmedetomidine)

1.   NRS scores at 30 minutes, 2, 6, 12, and 24 hours.

2.   Mean flow velocity and Pulsatility index in the middle cerebral artery at baseline, 1, 6, and 24 hours with Trans-cranial Doppler (TCD).

3.   Patient satisfaction score at 24 hours.

4.   Occurrence of any adverse effects.

5.   Onset of analgesia and duration of action       

 PDPH is a distressing complication that occurs due to accidental dural punctures or intentional punctures during spinal anesthesia, lumbar punctures, or intrathecal anticancer drug or antibiotic injections. The incidence and severity of PDPH are influenced by the types of needles, multiple attempts, and working with obstetric patients. An autologous Epidural blood Patch (EBP) is the gold standard for treating PDPH, but it is not recommended for patients with PDPH.

The sphenopalatine ganglion (SPG) is a small, triangular-shaped parasympathetic ganglion located in the pterygopalatine fossa. It sends fibers to various glands and parts of the nasal cavity, paranasal sinuses, palate, and upper pharynx. An SPG block can block the postganglionic parasympathetic, sympathetic neurons, and somatic sensory afferents, which diffuse the conduction of pain caused by various factors.

Indications for SPG block include managing acute and chronic facial/head pain, cluster headaches, trigeminal neuralgia, temporomandibular joint pain, postherpetic neuralgia, Sluder’s neuralgia, paroxysmal hemicrania, atypical facial pain, pain due to head and neck cancer, complex regional pain syndrome (CRPS) I and II, and vasomotor rhinitis.

The Monro-Kellie hypothesis states that when CSF is lost after a dural puncture, the intracranial volume is restored through compensatory vasodilation, causing a severe headache. The parasympathetic neurons in the SPG mediate this vasodilation, inhibiting parasympathetic activity and providing symptomatic relief.

There are several ways to perform a sphenopalatine ganglion block, including trans-nasal, trans-oral, sub-zygomatic, and lateral infratemporal approaches. Trans-nasal SPG block is often the simplest method for PDPH. Still, there are potential complications such as nasal discomfort, local irritation, failure to relieve symptoms, infections, allergic response, vasovagal response, and motor block of the face.

Dexmedetomidine is a potent alpha-2 receptor agonist with sympatholytic, sedative, amnestic, and analgesic properties. It reduces the hemodynamic response to laryngoscopy and intubation. Nebulized delivery is preferred due to its bioavailability, position, and absence of discomfort, coughing, vocal cord irritation, and laryngospasm compared to intranasal administration.

Total Number of Patients:

The sample size for this study was computed using statistical software. The power was set at 80%, alpha error at 5%, an equivalence margin of 1, an anticipated difference of 0.5, and a standard deviation of 0.8. Based on these results, 64 patients were needed at this equivalence trial. Considering a 10% loss to follow-up, we decided to enroll 35 patients in each group.

Inclusion criteria:

1.     Adult Parturient with PDPH defined as a moderate to severe NRS pain score of ≥4 in an upright position that developed within 5 days after an intended or accidental dural puncture.

2.     The headache must have persisted for at least 1 day after the dural puncture and must have been intractable to treatment with fluid and paracetamol.

      Exclusion criteria:

1)  Patients not giving consent for the study

2)  Hypertensive disorders of Pregnancy

3)  Known allergy to local anaesthetics 

4)  Cardiac abnormalities and heart Failure

5)  History of chronic headache, migraine, convulsions and cerebrovascular accident

6)  History of nasal bleed, deviated nasal septum, nasal polyp

Study design:

A prospective, single-blinded, randomized study.

Study setting:

This study will be conducted at All India Institute of Medical Sciences, New Delhi.

    Study population:

     After obtaining the Institutional Ethical Committee approval and consent from all the post-parturient patients experiencing PDPH eligible for the study will be recruited for the study.

Investigations specifically related to projects:

Trans-crania Doppler (TCD)

Brief Methodology:

Randomization and Group Allocation

âš«   Randomization will be done by a computer-generated random number table.

âš«   Allocation concealment is ensured by enclosing assignments in sealed, opaque envelopes.

âš«   The assessor will be blinded to the allocation and treatment received.  

GROUP DESIGN

Sphenopalatine Block Group(S):

•      Bilateral trans-nasal SPG block with swab stick soaked with 2% lignocaine

              Dexmedetomidine Group(D):

·     Dexmedetomidine nebulization (1 µg/kg dexmedetomidine diluted with 4ml of 0.9% saline)

    METHODOLOGY

•       Patients were recruited to the study after providing informed written consent.

•       Routine pre-anesthetic checkup-History, physical examination, and laboratory investigations.

•       A 20G intravenous cannula will be secured in the patient.

•       Until postoperative day 5, all the patients were questioned and clinically examined two times a day for headache, and diagnosis of PDPH was determined using the international classification of headache disorders (ICH II) guidelines.

•       The severity of PDPH was assessed after sitting upright for 15 minutes using the Numerical Rating Score (NRS)

•       Patients with NRS≥4 were enrolled in the study.

•       All the patients enrolled are hospitalized till the relief of symptoms after intervention and followed up for 24 hours.

•       ASA standard monitor (Heart rate, blood pressure, and pulse oximeter) will be attached and monitored for 1 hour.

•       Bed rest + adequate fluid intake +Paracetamol 1 gm TDS given

•       Ketorolac as rescue analgesic 30 mg intravenously with a maximum dose of 120 mg/day.

INTERVENTIONS:

GROUP S (SPG BLOCK)

•       Patients will receive an SPG block with trans-nasally inserted cotton swabs in a supine position.

•       2ml of two cotton swabs soaked in 2% lignocaine will be inserted into each of the patient’s nostrils along the superior edge of the middle concha to the posterior wall of the nasopharynx. It will be kept for 10 minutes.

•       After the intervention, the pain score will be assessed in a sitting position.

•       Rescue analgesic intravenous ketorolac 30 mg will be given if adequate pain relief is not achieved.

GROUP D (Dexmedetomidine Group)

•       The medication for nebulization, dexmedetomidine, will be prepared by an independent investigator

•       1µg/kg of Dexmedetomidine will be diluted with 4 ml of 0.9% NS and administered using an electric compressor nebulizer, which usually takes around 10-15 minutes.

•       The investigator will oversee the entire procedure. Occurrence of any adverse events during the procedure (bradycardia, hypotension, decreased saturation) will be treated accordingly.

          TRANS-CRANIAL DOPPLER(TCD) Recording

•       TCD will be done with a 2Mhz TCD probe by an experienced neuro anesthesiologist in a supine or semi-recumbent position.

•       The middle cerebral Artery will be insulated through the Trans-temporal window.

•       Mean Flow Velocity (MFV), Peak Flow Velocity (PFV), and End-diastolic velocity (EDV) will be recorded. The MFV will be calculated using the formula;

                          MFV=1/3(3PSV+2×EDV).

•       Pulsatility Index (PI) is an automatically derived parameter. The value will be noted using the formula;

§  PI = (PSV-EDV)/MFV

•       TCD measurement will be done at specific intervals (baseline, 1, 6, and 24 hours) after intervention.

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