Nebulized Dexmedetomidine or Lidocaine for Treatment of Post Dural Puncture Headache in Parturients Undergoing Elective Cesarean Section Under Spinal Anesthesia

Post-dural puncture headache (PDPH) is a well-recognized and potentially serious complication of subarachnoid block. While advancements in spinal needle design have reduced its incidence in recent years, PDPH still affects a notable percentage of post-partum patients undergoing spinal anaesthesia, with rates ranging from 0.5% to 2%. Factors such as female gender, pregnancy, young age, low body mass index, dilutional anemia, and the preference for neuraxial anaesthesia during caesarean section (CS) increase the vulnerability of obstetric patients to PDPH. Therefore, managing this complication is critically important in obstetric anaesthesia. The exact cause of PDPH remains unclear, but there is substantial evidence suggesting that it stems from reduced cerebrospinal fluid (CSF) pressure due to continuous leakage through a dural tear, which exceeds the rate of CSF production. This imbalance can lead to PDPH, as even a modest loss of CSF volume (as little as 10%) can trigger traction on pain-sensitive intracranial structures when in an upright position, compounded by reflexive vasodilation. Various treatment strategies have been proposed, typically including bed rest in a supine position, fluid therapy, analgesics, and medications such as sumatriptan and caffeine. Dexmedetomidine (DEX) is a highly specific agonist of α2-adrenoreceptors known for inducing cooperative sedation, anxiolysis, and analgesia while minimizing respiratory depression. Additionally, it has been shown to mitigate the stress and inflammatory response triggered by surgical and anaesthetic procedures. Activation of α2-receptors in the substantia gelatinosa of the dorsal horn suppresses the firing of nociceptive neurons and inhibits the release of substance P. Furthermore, stimulation of these receptors in the locus coeruleus, a key modulator of nociceptive transmission, interrupts the transmission of pain signals, resulting in analgesia. Dexmedetomidine has been administered via intranasal and inhalational routes for various purposes, including premedication, sedation, and post-operative analgesia. Lidocaine nebulized is a novel method used recently for PDPH. Intranasal lidocaine can offer sphenopalatine ganglion block which can facilitate acute pain reduction in PDPH.

Inclusion Criteria: * Post partum headache for parturient with elective CS under spinal anesthesia with visual analog score (VAS) ≥ 4 \[14\] and Lybecker classification score ≥ 2 Exclusion Criteria: * Emergency caesarean section. * Pregnancy induced hypertension * Contraindications for sub-arachinoid block ( coagulopathy, infection ) * History of chronic headache, migraine, trigeminal neuralgia * Refusal to participate * History of cerebrovascular stroke * BMI\> 35 * Prior maxillofacial with nasal deformity, Recent nasal surgery (\<3 months) Nasal polyposis or severe allergic rhinitis * Severe OSA (AHI\>30) , OBESITY HYPOVENTILATION SYNDROME, CENTRAL APNEA SYBDROME * History of obstructive sleep apnea.