Preventative Effect of Combining Dexamethasone with Ondansetron on Postoperative Nausea, Vomiting and Shivering in Children Undergoing Caudal Anesthesia on Hypospadias Surgery

Although it has some adverse effects: postoperative nausea and vomiting (PONV) are frequent and morbidity-related complication in children, PONV is still present in almost twice the frequency of adults, 33.2-82%. shivering is one of frequent, undesirable adverse effects, The incidence of shivering is up to 40-60% even in regional anaesthesia leads to O2 consumption and CO2 production,So we target in this study two effective drugs with less side effects to reduse these adverse effects Ondansetron is a highly potent selective 5 hydroxytryptamine receptor antagonist, which is widely used as an anti-emetic, Its mechanism of action as anti-shivering is not clear and it is proposed to act centrally at the level of the pre-optic anterior hypothalamic region by inhibition of serotonin reuptake Dexamethasone: is a potent class of steroid drugs ,It prevents thermoregulatory shivering via its central inhibitory effect on the thermoregulatory center and prevents non thermoregulatory shivering by its anti-inflammatory activity, i.e. antagonizing the activation of the inflammatory responses and release of cytokines during surgery The anti-emetic properties of dexamethasone are well established but the mechanisms underlying this anti-emetic effect remain largely unknown

Inclusion criteria

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• Age from 2 to 12 years old.
• Patients with stable vital signs.
• Patients with normal laboratory investigations.
• Patients undergoing Caudal anaesthesia for infraumbilical surgeries

Exclusion criteria

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• Patient's parental refusal.
• Age < 2 or > 12 years.
• Contraindications to Caudal anaesthesia (Coagulopathy, increased intracranial pressure, or local skin infection ,pilonidal cyst and congenital anomalies of lower spine because of unclear or impalpable anatomy
• Patients with cardiac morbidities.
• Failure of caudal block
• Diabetes mellitus
• Convulsions.
• Known allergy to any drugs used in this study.