Hemodilution

E.J. Cohen, L.J. Camerlengo, and J.P. Dearing, Activated clotting times and cardiopulmonary bypass I. The effect of hemodilution and hypothermia upon activated clotting time. J. Extra Corpor. Technol. 12, 139-141 (1980). 

Sakai H, Tsai AG, Rohlfs RJ, et al. Microvascular responses to hemodilution with Hb vesicles as red blood cell substitutes influence of O2 affinity. Am J Physiol 1999 276 H553. 

Gelatin colloids consist of cross-Unked peptide chains obtained from collagen. They are employed for blood replacement, but not for hemodilution, in circulatory disturbances. 

Hemodilution Hematocrit, hemoglobin, and erythrocyte count usually fall about 7% initially and then recover to pretreatment levels. 

Fig. 8. Assessment of gut oxygenation status during surgery. Changes in CO2 gap in surgical patients randomized to Oxygent (RFC) or placebo (controls) (ANH = acute normovolemic hemodilution PP = post-protamine administration CC = chest closure p<0.05 between groups). The dashed line represents the upper limit of normal for CO2 gap (8 torr). Postoperative recovery of gut function was determined by shorter time to first bowel movement (2 vs. 5 days p<0.007) and earlier consumption of solid food (1.8 vs. 4.1 days p = 0.056). From Ref. [29], with permission.

Acetyl [ F] hypofluorite (CH3C02[ F]F), 14, 15 Acid-functional monomer, 362 Acute normovolemic hemodilution, 452 Acyclovir, 25... 

ANH. See Acute normovolemic hemodilution Anhydrous electrophilic fluorine, 12 Anhydrous [ F]fluorine, 14 Anoxic relaxation, 221... 

The most common adverse effects of IL-11 are fatigue, headache, dizziness, and cardiovascular effects. The cardiovascular effects include anemia (due to hemodilution), dyspnea (due to fluid accumulation in the lungs), and transient atrial arrhythmias. Hypokalemia has also been seen in some patients. All of these adverse effects appear to be reversible. 

Pioglitazone also causes fluid retention, possibly because of increased production of vascular endothelial growth factor (92). The safety profile of monotherapy and combined therapy with pioglitazone has been evaluated in 3500 patients over 2500 patient-years, and some data from post-marketing surveillance were included peripheral edema and hemodilution were common (93). 

Maternal oxytocin administration increases the rate of neonatal physiological jaundice in a dose-dependent manner (SEDA-13, 1310) (11). This effect may be due to hemodilution and an increased rate of hemolysis. 

Rehm M, Orth V, Scheingraber S, Kreimeier U, Brechtelsbauer H, Finsterer U. Acid-base changes caused by 5% albumin versus 6% hydroxyethyl starch solution in patients undergoing acute normovolemic hemodilution a randomized prospective study. Anesthesiology 2000 93(5) 1174-83. 

Total body irradiation, a routine preconditioning procedure for treatment of leukemia and aplastic anemia before bone marrow transplantation, decreased TAC of blood plasma by 36%, as estimated by cyclic voltammetry (C26). TAC was found to decrease by about 40% during chemotherapy of patients with various hematologic malignancies with busuflan, VP-16, and cyclophosphamide (D12). The controversial procedure of blood ozonation was reported to decrease blood plasma TAC by 20% (B17). Treatment of hypercholesterolemic patients with bezafibrate (600 mg/day) for 1 month decreased TAC of their blood serum (G16). Propofol anesthesia decreased TAC of blood plasma of patients by 9.5% this effect was caused by hemodilution because mean hemoglobin concentration of the blood decreased accordingly (S26). 

The aforementioned findings in rodents mirror results observed in dogs subjected to cardiac arrest with subsequent postischemic mild hypothermia of 1- to 12-h duration (38-44). For example, a 12-h period of 34°C hypothermia with hemodilution and elevated blood pressure reduced brain injury (e.g., hippocampus, neocortex, basal ganglia) and lessened functional deficits after cardiac arrest. However, in all of these studies the survival time was 4 d or less, and thus it has yet to be proven that postischemic hypothermia can permanently reduce ischemic brain injury in the dog. Based on the rodent literature, it would be useful to investigate more protracted bouts of mild hypothermia and assess longterm outcome in this intensive cardiac arrest model in the dog. 

As mentioned already, the artificial kidney is a classic example of chemical engineering prowess. The proper design of such devices requires a description of both water and solute transport to and from blood, across membranes, and to and from an adjacent fluid known as the dialysate. Variations on this theme include hemodilution, hemoconcentration, and hemofiltration. Applications of these same principles have been used to examine continuous ambulatory peritoneal dialysis. Oxygenation of blood,... 

Figure 8.9 Predicted three-dimensional distributions of oxygen partial pressure in tissue. Model simulations from Tsoukias et al. [196] are based on a realistic model of the microvascular network associated with skeletal muscle. Predicted partial pressure distributions are illustrated for a control simulation (upper panel) and for a simulation of hemodilution - reduced hematocrit - plus addition of blood substitute (lower panel.) Predicted oxygen tension in mmHg is indicated by grayscale. Figure provided courtesy of Nicolaos Tsoukias.

For subarachnoid hemorrhage surgical clipping of the causative aneurysm or resection of the arteriovenous malformation is the mainstay of treatment. Endovascular coiling of the aneurysm can also be performed. Post-operative infection (either brain or respiratory) is an uncommon complication and not believed to be any more common than after other invasive surgical procedures. Hypervolemic-hemodilution and hypertensive (HHH) therapy is used to prevent spasm. There may be a role for anti-inflammatory measures for the prevention of vasospasm and delayed cerebral ischemia, as shown in a recent pilot study of patients treated with statins (Lynch et al., 2005). 

When normovolemic hemodilution is performed, there is normally a substantial increase in cardiac output as a result of increased fluidity of the diluted bloodJ This increase in cardiac output is preserved when PFC emulsions are administered, which further enhances their 02-delivery capacity, ° while cell-free Hb products, because of vasoconstrictive effects, classically display an unchanged or reduced cardiac output that can negate the benefit of increased fluidityJ ... 

RBCs, circulate more easily in the capillary beds than RBCs. They will be present in large numbers in the plasma gaps that exist between red cells in the micro-circulation, thereby increasing O2 content. These plasma gaps are particularly large when the patient suffers from acute anemia or when hemodilution is practiced. It is likely that PFC particles not only transport O2, but also facilitate its diffusion from RBCs to the tissues by providing numerous stepping stones or dynamic chains of particles for O2 to travel The... 

Clinical efficacy of Oxygent was demonstrated in a Phase 3 clinical study in surgical patients. [See section on Augmented Acute Normovolemic Hemodilution (A-ANH )]. 

PFCs have no capability to react with and scavenge nitric oxide, and clinical trials with EYP-based PFC emulsions have shown no perturbation of hemodynamics, increased vascular resistance and arterial tension, reduced cardiac output or heart rate. Cardiac output increased normally in response to hemodilution. Coagulation function, including bleeding times, were unaffected by the administration of OxygentP ... 

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