SPINAL-ANESTHESIA BUT NOT GENERAL-ANESTHESIA ENHANCES NEUTROPHIL BIOCIDAL ACTIVITY IN HIP-ARTHROPLASTY PATIENTS

The purpose of this study was to compare neutrophil cidal activity dur ing general or spinal anaesthesia. Assays were performed on neutrophil s extracted from the blood of patients after surgery had been under wa y for one hour. First, the ability of the neutrophils to kill a standa rd laboratory strain of S. aureus was examined. Neutrophils extracted from the blood during surgery in the spinal anaesthetic group and incu bated with the staphylococci for one hour killed twice as many bacteri a than those from two groups of patients that received halothane or is oflurane general anaesthesia (P < 0.05). This effect persisted, to a l esser extent, in the spinal group neutrophils after two hours of incub ation with the bacteria. Second, neutrophils from patients under the s ame conditions of surgery and anaesthesia were tested to examine the e ffect of the different anaesthetic techniques on neutrophil biocidal m echanisms. Neutrophils extracted during surgery in the spinal group re leased more superoxide in response to phorbol-12-myristate-13-acetate (PMA) than those from both groups of patients that received general an aesthesia (P < 0.05). It is concluded that there is an increased state of reactivity of the neutrophil cell membrane NADPH oxidase system in patients receiving spinal anaesthesia than in patients receiving gene ral anaesthesia.