Intrathecal Injection of Pethidine Plus Dexamethasone Versus Bupivacaine Alone

Intrathecal Injection of Pethidine and Dexamethasone Versus Intrathecal Injection of Bupivacaine in Lower Extremity Orthopedic Surgeries: Comparative Study

Bupivacaine is commonly used as a sole agent for spinal anesthesia unlike pethidine. Pethidine (meperidine) is a unique opioid. In addition to its analgesic activity, it also has significant local anesthetic activity. This property enables it to be used as the sole agent for spinal anesthesia

pethidine compared favorably with bupivacaine as the sole anesthetic agent, providing excellent conditions for lower abdominal and pelvic surgery. Some studies showed that intrathecal pethidine has short motor recovery and prolonged postoperative analgesia in comparison to intrathecal bupivacaine. The side effects of pethidine in spinal anesthesia are pruritus nausea, vomiting and respiratory depression. A dose of 1mg/kg intrathecal pethidine provides surgical anesthesia .However, its effects are not widely available in recent studies. Dexamethasone is used as an adjuvant to local anesthetic during spinal anesthesia and other techniques of regional anesthesia, it reduces pain and prolongs the duration of post-operative analgesia. It was shown that intrathecal dexamethasone reduces the complications of spinal anesthesia such as arterial hypotension, nausea, vomiting and shivering. The investigators suppose that addition of intrathecal dexamethasone to pethidine may be a better alternative to intrathecal bupivacaine during spinal anesthesia for lower extremity orthopedic surgery with better outcome and less side effects

Patients will be anesthetized by spinal anesthesia by intrathecal injection of 3 ml hyperbaric bupivacaine 0.5% alone.

Patients will be anesthetized by spinal anesthesia by intrathecal injection of 1mg/kg preservative-free pethidine plus 4mg dexamethasone diluted to a volume of 3 ml with 0.9% sodium chloride

monitoring intraoperative changes in the blood pressure (BP) measured by mmHg and comparing it with the preoperative measures in both groups

monitoring intraoperative changes in the heart rate measured by beat per minute (BPM) and comparing it with the preoperative measures in both groups

assess the level of sensory block in both groups after spinal anaesthesia using the pinprick technique

assess the level of motor block in both groups after spinal anaesthesia using Bromage scale where grade 1 means (free movement of legs and feet) and grade 4 means (patient is unable to move legs or feet)

assess the need for intraoperative sedative medications as benzodiazepines and measure it by (mg/kg) or ketamine (measured by mg/kg) in both groups

assess the frequency of Intraoperative nausea, vomiting, shivering, pruritis and respiratory depression

Postoperative analgesic requirements regarding the time of its need and the dose required to achieve the desired analgesia.

Inclusion Criteria: Patient acceptance. Patients scheduled for lower extremity orthopedic surgery Both sex Patient's age >18 years. Patients with American Society of Anaesthesia (ASA)physical status I, II. Exclusion Criteria: Patient's age ≤18 years. Uncooperative patients and patients with psychological problems. Patients with contraindications to spinal anesthesia. Patients with contraindications to bupivacaine or dexamethasone or pethidine. Patients with ASA physical status III and IV. Morbid obesity (BMI >35).