Comparison of blood loss using fluorescein flow cytometry during total hip replacement under general or spinal anesthesia

Objective:, In this study we assessed differences in intraoperative blood loss using flow cytometry in patients undergoing total hip replacement under general (GA) or spinal anesthesia (SA). Patients and Methods: After approval of the ethics committee and written informed consent, 42 patients (ASA I-III) undergoing elective total hip replacement were included in this study. All perioperative data were recorded with an anesthesia information management system. Therefore, standardized electronic anesthesia record charts were configured according to the study protocol. Red cell volume was measured with sodium fluorescein using flow cytometry before induction of anesthesia and at the end of the surgical procedure. Surgical blood loss was determined with the calculated loss of red blood cells and the mean of all intraoperatively measured hematocrit levels. Results: Data of all 42 patients (18 GA, 24 SA) were evaluated. The electronic charts contained complete data sets of the patients' biometric data, laboratory parameters, and surgery times. The study revealed no significant differences (p < 0.05) between the groups for intraoperative blood loss determined by flow cytometry (GA 1,688 +/- 921 ml, SA 1,581 +/- 1,052 ml), mean body temperature (GA 35.5 +/- 0.5 degreesC, SA 35.6 +/- 0.4 degreesC), average mean arterial blood pressure (GA 90 +/- 7 mm Hg, SA 89 +/- 9 mm Hg), and duration of surgery (GA 125 +/- 46 min, SA 120 +/- 40 min). Conclusions: The controversially discussed influence of anesthesia technique on intraoperative blood loss in total hip replacement could not be confirmed by this study. GA as well as SA are equivalent techniques in hip surgery regarding circulatory parameters and body temperature.