Subcutaneous infusion anesthesia with diluted mixtures of prilocain and ropivacain

Background:Local anesthesia often suffices for surgery on the outside of th e body. In recent years, it has been found that such local anesthesia can b e adequately carried out using large amounts of highly diluted anesthetic s olutions. Methods: Using one or more common infusomats, we injected mixed a nesthetic solutions slowly, painlessly, paravenously, and automatically via subcutaneous infusion anesthesia (SIA) into the subcutaneous layer in a la rge group of patients scheduled for surgery. The local anesthetics used wer e prilocaine and ropivacaine (Xylonest and Naropin); these were diluted wit h original Ringer's solution with epinephrine (1:1,000,000) in 500-ml bottl es. The concentration of the mixture varied between 0.3% and 0.08% dependin g on the requirements of surgery. The needles used ranged from 30-gauge to 20-gauge needles, with a length of 1.5-10 cm. The speed of injection varied between 30 ml/h and 1500 ml/h, depending on the location, the requirements of the surgery and the needle size. Volumes usually ranged from 2 mi to 60 0 mi depending on the concentrations used. The maximum dose was approximate ly 4 mg/kg prilocaine and 2 mg/kg ropivacaine. Patients: We used this techn ique in preparing for 5020 major and minor skin operations in 3270 patients ranging in age from 0.5 years to 95 years (mean age 54 years). Microbiolog ical tests of the infusion system were carried out. Patients were asked abo ut their pain during anesthesia, operation, and postoperatively. Results: T here were no complications from local anesthesia. The technique proved safe and comfortable even for children and very sensitive patients. The median duration of postoperative anesthesia was 5 h (maximum 23 h). Choosing the c oncentration, the needle, the needle position, the flow rate, and the volum e requires some experience.