The Effect of Acute Hypervolemic Hemodilution on Blood Loss and Mononuclear Cell Counts during Bone Marrow Harvesting / 대한마취과학회지

BACKGROUND: Hypervolemic hemodilution (HHD) seems to be a good alternative to acute normovolemic hemodilution to reduce transfusion requirements because it requires less time and effort. In a prospective study in healthy donors, we studied the effects of HHD on blood loss and mononuclear cell counts of aspirated bone marrow which were transplanted. METHODS: After induction of anesthesia and positioning to prone, donors of the HHD group (n = 25) were administered 7.5 ml/kg of pentastarch and the same amount of Hartmann's solution prior to aspiration, but those of the control group (n = 25) were administered only 2 ml/kg/h of Hartmann's solution. Bone marrow was aspirated at the iliac spine and blood loss was replaced with pentastarch and Hartmann's solution for both groups. Hemoglobins and hematocrits were counted after induction, after hemodilution and the end of aspiration. Hemoglobins and mononuclear cell counts of aspirated bone marrow were also counted. RESULTS: HHD decreased hemoglobin from 13.2 +/- 1.1 g/dl to 10.7 +/- 1.0 g/dl significantly (P < 0.01). Even though hemoglobins of both groups at the end of aspiration were not different (9.3 +/- 2.3 g/dl at control vs 9.5 +/- 1.1 g/dl at HHD), calculated blood loss based on body weight through aspirated bone marrow was less in the HHD group (18.0 +/- 1.8% at control vs 16.3 2.0% at HHD, P < 0.05). There was no difference in counted mononuclear cell counts between the two groups (1.8 +/- 0.7 x 10(7)/ml at control vs 1.8 +/- 0.7 x 10(7)/ml at HHD). CONCLUSIONS: During bone marrow harvesting in healthy donors, HHD reduced blood loss through aspirated bone marrow, but does not affect transplanted bone marrow mononuclear cell counts.

The Effects of Hemodilution on Critical Oxygen Deliveries during Deliberate Hypotension by Esmolol or Sodium Nitroprusside in Dogs / 대한마취과학회지

BACKGROUND: Acute normovolemic hemodilution (ANH) and deliberate hypotension (DH) are methods used for reducing homologous transfusions in cases of massive intraoperative bleeding. Using the technique of combining ANH and DH, we can save more homologous blood than a single use of ANH or DH, but the risk of tissue hypoxia may increase. METHODS: Fourteen male dogs were used for this study and divided into two groups. After performing ANH by 25 ml/kg, mean arterial pressures were reduced to 60 mmHg by sodium nitroprusside (S group) or esmolol (E group). The critical oxygen delivery and the hemoglobin concentration at the critical oxygen delivery were determined by measurements of hemodynamic change, systemic oxygen delivery and systemic oxygen consumption during subsequent hemodilution. RESULTS: After performing ANH by 25 ml/kg, the cardiac output was significantly increased, and systemic vascular resistance and hemoglobin concentration were significantly decreased compared with control values. The critical oxygen deliveries were 179.6 ml/min in the S group and 169.1 ml/min in the E group. There was a difference in mean systemic oxygen consumption between the S group (123.4 +/- 16.7 ml/min) and E group (112.9 +/- 15.4 ml/min) above the critical oxygen delivery point (mean +/- SD). The hemoglobin concentrations at the critical oxygen delivery were 2.6 +/- 0.7 g/dl in S group and 4.0 +/- 1.3 g/dl in E group (mean +/- SD). CONCLSIONS: The critical oxygen delivery during hemodilution under DH by sodium nitroprusside was 179.6 ml/min and by esmolol was 169.1 ml/min. However, esmolol was higher in hemoglobin concentrations at the critical oxygen delivery than sodium nitroprusside. These results suggest thathemodilution under DH by esmolol rather than sodium nitroprusside requires more careful monitoring of systemic oxygen delivery for prevention of tissue hypoxia.

Effect of Hemodilution on Brain Damage after Focal Cerebral Ischemia in Rabbits / 대한마취과학회지

BACKGROUND: Hemodilution after focal cerebral ischemia increases cerebral blood flow to ischemic brain tissue and reduces neurologic injury. With rare exceptions, most studies have reduced hematocrit (Hct) to no less than 30%. We studied the effect of moderate hemodilution (hematocrit 27%) on cerebral infarct volume after focal cerebral ischemia in rabbits. METHODS: Twenty rabbits were divided into a control group (n = 10) and a hemodilution group (n = 10). In the control group, cerebral infarction was induced by embolization of the middle cerebral artery using an autologous blood clot without hemodilution. In the hemodilution group (n = 10), hemodilution of around hematocrit 27% was achieved by exchanging arterial blood with 10% hydroxyethyl starch 1 hour before embolization of the middle cerebral artery in the hemodilution group. Seven hours after embolization, coronal brain slices were made with 2 mm thickness at 1 cm from the frontal pole and stained with 2% 2,3,5-triphenyltetrazolium chloride. The infarct volume was quantitated by image analysis of photography of the infarcted area. RESULTS: The infarct volume of the cerebral hemisphere (25.9 +/- 8.9%), subcortex (16.3 +/- 3.1%) in the hemodilution group was significantly smaller than in the control group (34.9 +/- 8.9%, 19.3 +/- 5.1%) (P<0.05), but, in the cortex, the difference of infarct volume is not statistically significant between the control group (23.5 +/- 11.9%) and the hemodilution group (15.6 +/- 2.7%). CONCLUSIONS: These results indicate that moderate hemodilution (hematocrit 27%) reduces neurologic injury after focal cerebral ischemia.

The Effects of Acute Normovolemic Anemia Induced by Hemodilution on Tissue Oxygenation in Dogs: A Comparison of Systemic Oxygen Consumption, Arterial Lactate, Arterial Ketone Body Ratio and Gastric Intramucosal pH / 대한마취과학회지

BACKGROUND: The reduction in hematocrit (Hct) by hemodilution tends to cause an increase in cardiac output and a proportional decrease in arterial oxygen content. Additionally the reduction of systemic oxygen delivery (DO2) leads to significant differences in regional blood flow. It is therefore important to characterize the effects of hemodilution on regional oxygen metabolism in individual organs. This study was undertaken to evaluate and compare the effects of acute normovolemic anemia induced by hemodilution. METHODS: Six dogs were anesthetized and mechanically ventilated. Catheters were inserted in the right femoral and pulmonary arteries for blood sampling, and a gastric tonometer catheter was inserted into the gastric lumen. Baseline measurements of systemic hemodynamics, arterial ketone body ratio (AKBR), gastric intramucosal pH (pHi) and arterial lactate were recorded. Hemodilution was then begun by 6% pentastarch and was made in four levels of hematocrit values of 20%, 15%, 10% and 6%. RESULTS: Mean arterial pressures of Hct 10% and 6% was decresaed (P < 0.05) and Hct 15% and 10% increases in cardiac output and pulmonary capillary wedge pressure (PCWP) were observed. Central venous pressure and mean pulmonary arterial pressure were incresed (P < 0.05) at Hct 15%, 10% and 6%. DO2 progressively decreased (P < 0.05). AKBR and pHi began to decreased at Hct 15%. Arterial lactate decrease at Hct 15% and was above 7.4 mmol/L at Hct 6%. CONCLUSIONS: By the measurements of AKBR and pHi, the disturbance of splanchnic oxygenation can be detected early compared to those of O2 in terms of oxygen metabolism and the critical point of DO2 during acute normovolemic anemia induced by hemodilution.

Effects of Sodium Nitroprusside-induced Hypotension under Acute Normovolemic Hemodilution on the Cardiovascular System and Systemic Oxygen Balance in Dogs / 대한마취과학회지

BACKGROUND: To decrease homologuous transfusion and bleeding, Acute Normovolemic Hemodilution (ANH) may be combined with induced hypotension. Tissue oxygen balance may be in danger because of decreased tissue perfusion pressure by induced hypotension and reduced arterial oxygen content by ANH. Thus it is necessary to evaluate effects of induced hypotension combined with ANH on hemodynamics and systemic oxygen balance. METHODS: In 6 mongrel dogs anesthetized with N2O-O2-enflurane and paralyzed with vecuronium, ANH was performed up to half of initial level of hemoglobin with isovolemic pentastarch infusion, and then mean arterial pressure (MAP) was lowered by 30% of the initial value by intravenous administration of Sodium Nitroprusside (SNP). Various hemodynamic parameters were measured before and after ANH and 15, 30, 45 and 60 minutes after induction of hypotension and 15 minutes after the end of hypotension. RESULTS: Heart rate was not changed significantly throughout the study. Central venous pressure increased significantly after ANH but decreased to the initial value after induced hypotension. Systemic vascular resistance showed significant decrease after ANH, more significant decrease after induced hypotension and slight increase after discontinuation of SNP. Cardiac output increased markedly by ANH and maintained during induced hypotension. Oxygen flux decreased significantly after ANH but slightly increased after induced hypotension. Oxygen consumption and Oxygen extraction ratio were maintained throughout the study. There were no acidemia and hypoxemia throughout the study. CONCLUSION: The combined use of ANH and induced hypotension with SNP is safe in the aspect of cardiovascular system and systemic oxygen balance.

Changes of Thrombelastography in Acute Isovolemic Hemodilution Undergoing Total Hip Replacement Arthroplasty / 대한마취과학회지

BACKGROUND: Acute isovolemic hemodilution is one of the autologous transfusion which diminishes intraoperative blood loss and avoids homologous transfusion. A method of assessment of hemostatic function by whole blood is thrombelastography, which is a sensitive indicator of platelet interreaction with protein coagulation cascade. We investigated the effect of intraoperative isovolemic hemodilution on blood coagulation as measured by thrombelastography. METHODS: We studied in twenty-one patients undergoing elective total hip replacement arthroplasty. Hemodilution was done with Hartmann's solution and pentastarch and prothrombin time, activated partial thromboplastin time and native whole blood thrombelastography were performed preoperatively, immediate postoperative and days 2 postoperatively. RESULTS: The Hb, Hct and platelet count decreased significantly after hemodilution. The thrombelastographic changes included decreases in r and k with concurrent increases in alpha angle and MA in immediate postoperative time. On days 2, there were further increase in alpha angle and MA. These changes indicate enhanced procoagulant activity and progressive increase in maximum clot strength. Conclusion: Acute isovolemic hemodilution with Hartmann's solution and pentastarch induced hypercoagulable state without any serious complication in total hip replacement arthroplastic surgery.