Acute Preoperative Hemodilution in Patients Undergoing Radical Prostatectomy

Abstract

Despite published guideline and consensus conference recommendations, the role of acute preoperative hemodilution in elective surgery has not been defined. We performed a case study analysis of this technique in a large surgical program in order to estimate its degree of efficacy as practiced routinely, and to better define its role as a blood conservation strategy. Patients undergoing elective radical prostatectomy by one surgeon during a 3-yr period were analyzed retrospectively for blood loss, hematocrit levels, records of acute hemodilution, and transfusion outcomes. Patient blood volumes were determined by nomogram; final hematocrits after discrete blood volumes lost by surgery or by hemodilution were estimated. Sixteen (4.4%) of 410 total patients reviewed underwent hemodilution, representing 0 (O%), 4 (3%), and 12 (8%) of the 112,146, and 152 patients undergoing surgery in years 1, 2, and 3, respectively. Median whole blood volume and mean red blood cell (RBC) volume removed by hemodilution was 1000 mL (range, 400-1500 mL) and 338 mL (range, 156-585 mL), respectively, representing 15% of patients' admission RBC volume. Net intraoperative RBC volume "saved in losses by this technique was 95 mL (range, 25-204 mL), representing only 9.3% (range, 4%-17%) of total RBC volume lost during hospitalization. RBC volume removed by hemodilution constituted 34% (95-283 mL) of the total RBC volume transfused. We conclude that use of acute preoperative hemodilution remains in evolution and, as a single blood conservation intervention, contributes only modestly to blood conservation.(Anesth Analg 1994;78:932-7) ecent guidelines for blood transfusion in the surgical setting have emphasized that autologous blood should be procured preoperatively when possible (1'2). While the demonstrated safety and efficacy of preoperative donation in elective surgery has made this practice a standard of care in certain elective orthopedic (3) and urologic procedures (4), this practice can be time consuming and expensive (5). Several reports have also suggested that preoperative autologous blood donation may contribute to cardiovascular morbidity in geriatric patients (6,7). In contrast, acute preoperative hemodilution, in which autologous blood is procured immediately before surgery, remains an underutilized blood conservation intervention. We have therefore reviewed the experience with this technique in patients undergoing radical prostatectomy with a single surgeon at our institution, in order to analyze its efficacy as a blood conservation intervention. In addition, we define a methodology that can serve as an institutional approach in analyzing the effectiveness of blood conservation strategies. MethodsThe records of patients undergoing radical prostatectomy for Stage A or B prostate cancer by a single surgeon (WJC) during a 3-yr period were reviewed. Radical retropubic prostatectomy was performed as described previously (8) under general anesthesia. Predeposit of autologous blood and/or acute preoperative hemodilution were offered to...

Autologous Blood Procurement in the Surgical Setting: Lessons Learned in the Last 10 years

“…This can be compared with 947 ml RBC lost if hemodilution had not been performed. Thus, the surgical RBC volume loss 'saved' by hemodilution in this patient represents only 205 ml, or the equivalent of one blood unit [24,52]. The 'savings' in RBC losses are even less in smaller patients who undergo more modest hemodi lution with less surgical blood losses.…”

“…It has been suggested to remove blood until the hematocrit is of a certain value, e.g., 27-30% [51]. Recently, the efficacy of moderate hemodilution has been questioned [52,53]. As illustrated in figure 4, the removal of three blood units in a 100-kg man with a reduction in preoperative Hct level from 44 to 32% and who subsequently undergoes radical prosta tectomy with an estimated blood loss of 2,600 ml results in 732 ml in RBC lost.…”

“…The 'savings' in RBC losses are even less in smaller patients who undergo more modest hemodi lution with less surgical blood losses. In the same report, a case study analysis of a 60-kg man who underwent hemodi lution of two units before undergoing a radical prostatecto my procedure, with an estimated surgical blood loss of 1,600 ml saved only 95 ml in RBC losses, or the equivalent of '/2 unit of blood [52].…”

Acute Normovolemic Hemodilution

“…Mathematical modeling has suggested that hemodilution to preoperative hematocrit levels of less than 20%, accompanied by substantial blood losses, would be required before the red cell volume saved by hemodilution became clinically important 6 . For example, a case study analysis of patients who had undergone "minimal" acute normovolemic hemodilution (representing only 15% of patients' baseline blood volume) estimated that only 100 mL red cell volume (the equivalent of 1/2 unit of blood) was "saved" in a 60 kg man who underwent hemodilution with the removal of two blood units, followed by radical prostatectomy with an estimated surgical blood loss of 1600 mL 7 .…”

Blood Transfusion and Blood Conservation: Cost and Utilization Issues

“…The measurement of arterial blood gases and mixed venous oxygen saturation, as well as calculations of arterial-venous oxygen content difference, oxygen consumption, and oxygen extraction may help determine a minimum acceptable hematocrit for a specific patient (81). Recently, the efficacy of hemodilution has been questioned (82,83). As illustrated in Figure 5, the removal of three blood units in a 100 kg man (0) with a reduction in preoperative hematocrit level from 44% to 32% and who subsequently undergoes radical prostatectomy with an estimated blood loss of 2,600 ml (0), results in 732 ml in RBC lost.…”