Effect of Propofol Administration Time on the Incidence and Severity of Intrathecal Morphine-induced Pruritus in Parturient Undergoing Elective Cesarean Delivaries

Neuraxial Anaesthesia is a frequent anaesthetic approach for cesarean delivery and other lower abdominal and lower limb anaesthetic procedures. Neuraxial morphine addition to local anaesthetic provides an effective and prolonged postoperative analgesia, but has been associated with a frequent incidence of pruritus and postoperative nausea and vomiting (PONV).

Neuraxial opioids are thought to act on central nervous system pathways to cause pruritus. Although precise mechanisms are incompletely understood, Numerous interventions have been investigated to prevent opioid-induced pruritus in the peripartum period as: Opioid receptor agonist-antagonists, Serotonin receptor antagonists.

There is dense concentration of opioid receptors and 5-HT3 receptors in the dorsal part of the spinal cord and nucleus of the spinal tract of the trigeminal nerve in the medulla. Activation of these receptors by neuraxial opioid administration or by circulating estrogen in parturient results in pruritus which is usually localized to face, neck, or upper thorax.

Propofol exerts its antipruritic action through inhibition of the posterior horn transmission in spinal cord. Series of clinical trials have reported that a sub-hypnotic dose of propofol is equally effective in reducing the incidence of pruritus following intrathecal morphine. however these studies have limited information about dose and timing of administration of propofol.

Inclusion criteria

• Parturient of American Society of Anaesthesiologists (ASA) class I or II physical status.
• Age: 20-40 years.
• At term gestation (≥ 37 weeks) with a singleton uncomplicated pregnancy.
• Elective cesarean delivery under intrathecal anaesthesia

Exclusion criteria

• Parturient refusal.

• Significant organ dysfunctions (e.g., cardiac, respiratory, renal, or liver disorders).
• Morbid obesity (BMI >35).
• Parturient with known hypersensitivity to propofol, morphine or amide local anaesthetics.
• Parturient with pruritogenic systemic disease.
• A coexisting skin disorder or preexisting pregnancy induced pruritus.
• Parturient with any contraindication for intrathecal anaesthesia, e.g. coagulopathy.
• Emergency cesarean section.
• Failed or unsatisfactory intrathecal block.