Is It Safe To Apply The New Technology Preoperative Acute Hy Pervolumic Hemodilution To The Elderly Patients

ObjectivePreoperative acute hemodilution is a means of blood saving. The procedure may differe as acute nomovolemic hemodilution (ANH), acute hypervolemic hemodilution (AHH), and non-nomovolemic hemodilution (NNH). Compare to ANH, AHH had been used only for resent few years and was less studied. AHH in aged patients has not yet been studied. The purpose of this study was to observe the oxygen delivery-demand balance and hemodynamic changes in aged patients during AHH.MethodsTen elderly patients aged 68 to 82 in the old patient group and nine younger patients aged 42 to 56 in the control group were studied. All subjects were scheduled for major elective surgery, preoperative Hct > 30 % , Hb>100g-L"1, body weight between 50Kg~~ 70Kg , ASA class I~II. Anesthesia was induced with propofol 2mg/kg, fentanyl 5-6ug/kg and vecuronium 0.12mg/kg, maintained with isoflurane at 1.2%-1.5% end-expiratory concentration. After pulmonary artery catheter was placed, AHH was started by infusing 6% HAES (200/0.5) at the rate of 25ml/min. When 500ml, 800ml, 1000ml infused, Hb, SaO2, SvO2, MAP, CVP, HR, PAWP, CI, SV, SVRI, DO2, VO2 was measured or calculated. Oxygen delivery- demand balance and hemodynamic change was analyzed and compared.ResultsAfter AHH, Hct was reduced significantly (32.5 % to 26.5% for the elderly and 33.9% to 26.0% for the control group). As a result, CaO2 reducedfrom MSml-L"1 to 117 ml-L"1 in the elderly and from 154 ml-L"1 to 119 ml-L"1 in the control. However, DO2 was remarkably elevated from 335 + 88ml-min~1-m2 to 482+173 ml-min-m2 in the aged patients and 448 ?1 97ml-min~1-m2 to 482?141 ml-min"1-m2 in the younger. Increase of cardiac index (CI) compensated the decrease of CaO2 and maintained DO2. CI was increased from 2.4 + 0.6 L-min-'-nT2 to 4.1 + 1.4 L-min-m'2 (P<0.01) in the elderly, and from 12.9 ?1.1 L-mirf'-m'2 to 4.0 + 0.9 L-min^-m"2 (P<0.05) in the control. SV, CVP, PAWP were all increased in consequent to infuse of HAES. MAP and HR were relatively stable in both groups and no clinically observable respiratory or circulatory disorder fund. However, the older patients had less increase in SV, CI and more increase in PAWP, 4 cases in the aged patients and 1 case in the younger group PAWP exceeded 2.4kPa, with the highest of 2.67kPa.ConclusionsBoth aged patients and the younger patients maintained oxygen delivery-demand balance during AHH. Increase of CI compensated thedecrease of CaO2 and maintained DO2. MAP and HR were stable in both groups. PAWP, CVP changes were more profound in the aged patients, but no clinical observable adverse reaction was fund. Thus AHH may be applied to the aged patients, but close monitoring was advisable.