Intravenous Lidocaine for Treating Intrathecal Fentanyl Induced Pruritus

Intravenous Lidocaine for Treating Intrathecal Fentanyl Induced Pruritus

The study will assess efficacy of intravenous lidocaine 1 mg/kg diluted with 0.9% sodium chloride to a volume of 100 ml to suppress intrathecal fentanyl induced pruritus. This will be compared to control group who will receive 100 ml normal saline as placebo.

The main outcome is regression of initial VAS score with incidence of pruritus.

The study will include adult patients who are admitted for orthopedic operations and Urosurgery who are planned to receive spinal anesthesia. The study will include adult patients aging from 18 to 70 years old. ASA I to III. The study will exclude the patients who receive antihistamine drugs, patients who suffer any type of coagulopathy, patients who are suffering any type of pruritus before receiving spinal anesthesia and patients who are known allergic to lidocaine. All the patients will receive 500 ml ringer lactate as a volume preload. The patients will be monitored by SPO2, Noninvasive blood pressure and ECG. The spinal anesthesia drugs will be hyperbaric bupivacaine (the dose will be adjusted according to the required level of anesthesia) and 25 mic of fentanyl as an additive. The subjects of the study will not receive any type of sedation. If any patient suffered bradycardia associated with hypotension which necessitate management by atropine or ephedrine, he will be excluded from the study.

Before the surgery, patients could cooperate and understand the Visual Analogue Score (VAS) scale. Patients will be explained about the use of VAS for grading the severity of pruritus on a scale of 0 to 10. VAS = 0 means no pain or itching, VAS = 10 means worst sensation and VAS > 4 means it need intervention. The affected areas by itching will be asked.

The study group will receive lidocaine (2%) 1mg/ kg iv diluted by normal saline to a volume of 100 ml. The VAS will be assessed every 10 minutes for 60minutes after the treatment. A regression of more than 4 points of VAS score is considered a success and if less than 4 points , it will be considered as a failure.

The control group will receive 100 ml of normal saline as placebo effect and VAS will be assessed in same manner as the study group.

Inclusion Criteria:

• patients who are admitted for orthopedic operations and Urosurgery who are planned to receive spinal anesthesia.
• The study will include adult patients aging from 18 to 70 years old. ASA I to III.

Exclusion Criteria:

• the patients who receive antihistamine drugs
• patients who suffer any type of coagulopathy
• patients who are suffering any type of pruritus before receiving spinal anesthesia
• patients who are known allergic to lidocaine.