HEMODYNAMIC EFFECTS OF BLOOD TRANSFUSION IN CHRONIC ANEMIA

Ascariasis, trichuriasis and fatal non-transfusion

Blood transfusion for chronic anemia can lead to acute or decompensated heart failure in patients who have fluid overload as part of their compensatory response and/or have intrinsic heart disease, and then it could be fatal in such clinical scenarios. This is the report of a case of profound chronic anemia in a young male patient, who was not transfused and then developed confusion followed by terminal cardiopulmonary arrest. Autopsy revealed severe trichuriasis to be the cause of the anemia, along with severe ascariasis, but minimal intrinsic brain disease. This supports the conclusion that anemia was the cause of the confusion, and the lesson that confusion may be a sign that the benefit of blood transfusion outweighs the risk in a patient with severe chronic anemia.

Lung function, transfusion, pulmonary capillary blood volume and sickle cell disease

Lung function abnormalities occur in children with sickle cell disease (SCD) and may be associated with elevated pulmonary blood volume. To investigate that association, we determined whether blood transfusion in SCD children acutely increased pulmonary capillary blood volume (PCBV) and increased respiratory system resistance (Rrs5). Measurements of Rrs5 and spirometry were made before and after blood transfusion in 18 children, median age 14.2 (6.6-18.5) years. Diffusing capacity for carbon monoxide and nitric oxide were assessed to calculate the PCBV. Post transfusion, the median Rrs5 had increased from 127.4 to 141.3% predicted (p<0.0001) and pulmonary capillary blood volume from 39.7 to 64.1 ml/m2 (p<0.0001); forced expiratory volume in one second (p=0.0056) and vital capacity (p=0.0008) decreased. The increase in Rrs5 correlated with the increase in PCBV (r=0.50, p=0.0493). Increased pulmonary capillary blood volume may at least partially explain the lung function abnormalities in SCD children.

Expanding role of a blood center

Materials and Methods:

The study was performed on prospective donors who reported to the Department of Transfusion Medicine. Individuals deferred due to hypertension contributed the study population. They were compared with age and sex matched donor controls. Demographic details were recorded in a proforma. On identification of a hypertensive individual, consequent two comparable donors were taken as controls with a total of 50 hypertensive subjects. Hypertensive status of the subjects were assessed based on the criteria formulated by the WHO-ISH and US Seventh Joint National Committee report on prevention, detection, evaluation and treatment of high blood pressure.

Results:

About 0.95% of healthy blood donors had undetected hypertension. Mean age at detection of hypertension in the study group was 35.44 ± 7.69 years. Higher BMI was observed in the hypertensive group compared to normotensive control group with P value significant at 0.0001.

Conclusion:

About 1% of healthy individuals were found to have undetected hypertension. Though the study was not designed to determine the prevalence of hypertension in the region, it is a rough estimate of the proportion of undetected hypertension in the local population as donors are considered as representative of healthy population.

Anemia and Cost in Medicare Patients With Congestive Heart Failure

The objective of this study was to examine the total cost to Medicare associated with the presence of anemia in congestive heart failure (CHF) patients. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify anemia, CHF, and comorbid conditions in 2002, and total Medicare costs were calculated for 2003. The mean patient age was 77.8 years. Anemia, present in 32% of CHF patients, was associated with older age, female sex, non-white race, and increasing burden of comorbidity. The total per-member-per-month cost in 2003 was $1781.01 among CHF patients with anemia in the preceding year compared with $1142.38 for CHF patients without anemia, a ratio of 1.56 (95% confidence interval, 1.5589-1.5592). When adjustment was made for baseline demographic factors and comorbid conditions, the corresponding ratio was 1.25 (95% confidence interval, 1.2546-1.2548). Anemia, a common association of CHF in elderly patients, is an antecedent association of increased societal medical expenditure.

Physiologic aspects of anemia

The most important adaptive responses from a physiological stance involved the cardiovascular system, consisting in particular of elevation of the cardiac output and its redistribution to favor the coronary and cerebral circulations, at the expense of the splanchnic vascular beds. The evidence regarding these physiological responses, especially in experimental studies that permit the control of many variables, is particularly powerful and convincing. On the other hand, there is a remarkable lack, in quality and quantity, of clinical studies addressing how normal physiological adaptive responses may be affected by a variety of diseases and conditions that often accompany and may complicate anemia, and interactions with other such compounding variables as age and different patient populations. For these reasons, it is not possible to offer guidelines on how to increase, maintain, or even to determine optimal DO2 in high-risk patients and how best transfusion strategies might be used under these conditions. From the brief review of physiological principles and the strong consensus in the literature, it is evident that cardiac function must be a central consideration in decisions regarding transfusion in anemia, because of the critical role it plays in assuring adequate oxygen supply of all vital tissues. Particular attention should be paid to the possible presence of CAD or incipient or cardiac failure, as these conditions may require careful transfusions to improve DO2 at levels that may not necessitate such interventions when cardiac disease is absent. Although the cerebral circulation also serves an obligate aerobic organ unable to tolerate significant hypoxia, there is little convincing evidence to support the notion that cerebral ischemia is aggravated by anemia and that this can be prevented by improved DO2 through rapid correction of anemia. Consequently, the arguments favoring transfusions in the presence of ischemic heart disease do not appear to apply to occlusive cerebrovascular disease. Because firm evidence is lacking on the interactions of concurrent diseases and anemia in various patient populations, understanding of the physiological consequences of anemia, and of the diseases concerned, is useful but not fully sufficient to provide firm and rational guidance to transfusion practice in specific complex clinical instances. A good deal of clinical and experimental investigation is required to support fully rational and comprehensive guidelines. In the meantime, prudent and conservative management, based on awareness of risks and sound understanding of the normal and pathological physiology, must remain the guiding principle.

Hematocrit, blood pressure, and hypertension. The Gubbio Population Study

Baseline data from the Gubbio Population Study in north central Italy were used to investigate the relation of hematocrit to blood pressure and hypertension among 2,809 men and women aged 25-74 years. Independent of gender, age, and other confounders, the hypertensive group had a higher hematocrit than the nonhypertensive group (p less than 0.001). In comparison with the untreated hypertensive group, the hypertensive group being treated with diuretics or with other drugs only had similar mean hematocrit levels despite significantly lower blood pressures. Hematocrit was positively correlated with systolic pressure (r = 0.085, p less than 0.01 and r = 0.264, p less than 0.001 for men and women, respectively) and diastolic pressure (r = 0.214, p less than 0.001 and r = 0.266, p less than 0.001). In both sexes, whether or not the treated hypertensive group was included, age-adjusted prevalence of hypertension and average blood pressure were higher for persons in higher quintiles of hematocrit (p less than 0.001). The association of hematocrit with blood pressure and hypertension was significant and independent of several confounders. The regression coefficient of blood pressure on hematocrit ranged between 0.410 and 0.620 mm Hg per unit of hematocrit for systolic pressure and between 0.371 and 0.581 for diastolic pressure, depending on gender and whether the treated hypertensive group was included in multiple regression analysis. Based on exponentiation of the multiple logistic coefficient, prevalence of hypertension was at least two times greater for persons whose hematocrit levels were higher by 10 units.

Effect of different amounts of blood transfusion given at different speeds on left ventricular filling pressure in cases of chronic severe anemia

Pulmonary capillary 'wedge' pressure (PCWP) was measured before and after transfusion of 1 and 2 units of blood @ 5 and 10 ml/min. in 40 adult cases of chronic severe anemia (CSA). The cases were randomly divided into 4 subgroups of 10 cases each. Following blood transfusion (BT), PCWP increased significantly in all the 4 subgroups (p less than 0.001). The highest rise in PCWP was recorded when 2 units of blood were transfused at a rate of 10 ml/min, and the rise was minimum when 1 unit of blood was transfused @ 5 ml/min. Out of the two variables--speed and amount of BT--the amount was more important. It is, therefore, concluded that administration of 2 units of blood in case of CSA at a rate of 5 or 10 ml/min is not desirable and that transfusion of 1 unit of blood @ 5 ml/min is quite safe.

A comparative study of conventional vs rapid speed of blood transfusion in cases of chronic severe anemia

Pulmonary capillary 'wedge' pressure (PCWP) was studied in 20 cases of chronic severe anemia before and after transfusing one unit of blood. They were divided into 2 groups of 10 age and sex matched cases. Blood was transfused at a speed of 2 ml/min in group A and 5 ml/min in group B. Pretransfusion PCWP was normal in all the cases. Following blood transfusion (BT) 'wedge' pressure increased significantly (p less than 0.001) in both the groups being 17.2% and 29.2% in group A and B respectively. The difference in the rise of PCWP between the two groups was not statistically significant (p greater than 0.05). All the cases tolerated BT very well. It is therefore, concluded that transfusion of one unit of blood at a speed of 5 ml/min is nearly as safe as when it is transfused at a rate of 2 ml/min (conventional speed) so far as the cardiopulmonary haemodynamics are concerned.

Left ventricular filling pressures after rapid blood transfusion in cases of chronic severe anemia

Left ventricular filling pressure as reflected by pulmonary artery wedge pressure was measured in 15 adult cases of chronic severe anemia before and after rapid and large blood transfusion, using Swan-Ganz monitoring catheters. Pre-transfusion PAWP was normal in 80% of the cases but increased significantly after blood transfusion (P less than 0.001), reaching more than 18.0 mm Hg in 3 cases. No correlation was found between right atrial pressure and PAWP. In is concluded that administration of 2 units of blood at a rapid speed (8.92 +/ 1.73 ml/minute) in cases of CSA is not always quite safe so far as pulmonary hemodynamics are concerned and should therefore be avoided.

Deaths from severe megaloblastic anaemia in hospitalised patients

In a series of 128 consecutive patients dying from severe megaloblastic anaemia, over half the deaths occurred within one week of hospitalisation and one third were sudden and unexpected. Congestive cardiac failure was extremely common in these patients and was often associated with pleural effusions. Just over half the patients were examined at autopsy and of these 42% had pleural effusions and 15% had pericardial effusions. The cause of the latter is unclear as is their clinical significance, nevertheless this condition has not previously been reported in the megaloblastic anaemias and may well play a part in the fatal outcome in such patients. Blood transfusion was administered to over half the patients, usually in the form of whole blood. It is recommended that transfusions be used sparingly, and consist of cells or preferably exchange transfusion, the latter being of particular value in the elderly or in those with pre-existing cardiac failure.

Hemodynamics of uremic anemia

This study was undertaken to assess the importance of an elevated cardiac output in the generation of the hypertension associated with chronic renal failure. Forty stable uremic patients on a program of maintenance hemodialysis underwent hemodynamic studies. Cardiac index measured by dye dilution was found to be significantly elevated. Calculated peripheral vascular resistance was normal despite elevated blood pressure. Six patients underwent serial hemodynamic studies over a period of 6 to 12 weeks while being transfused with packed red blood cells to a normal hematocrit. Blood volume and body weight were constant during the study period. Cardiac index decreased during transfusion, reaching a normal level at a hematocrit of 30%. Diastolic blood pressure progressively rose, averaging an increase of 20 mm Hg at a hematocrit of 40%. Peripheral vascular resistance increased by 80% at a hematocrit of 40%.

We concluded that the elevation of cardiac index in uremic patients is secondary to anemia and is reversible when the hematocrit is raised over 30%. The high cardiac index is not responsible for hypertension because restoration of cardiac index to normal by transfusion raises blood pressure rather than lowers it.

Plasma renin activity in end-stage kidney disease

Plasma renin activity, fluid and electrolyte balance, and hemodynamic conditions were measured in seven hypertensive patients with end-stage renal disease before and after five exchanges of peritoneal dialytic fluids which removed large amounts of water and sodium, sodium but little water, and little water and sodium, respectively. The subjects had normal plasma renin activity, severe anemia, high cardiac output, high total peripheral resistance, and elevated blood volume. Plasma renin activity rose with large losses of sodium and water but changed slightly when large amounts of sodium with little water or small amounts of sodium and water were removed. Plasma renin activity prior to dialysis did not correlate with mean arterial pressure, blood volume, cardiac index, total peripheral resistance, or serum sodium concentration. Change in plasma renin activity with dialysis correlated inversely with change in mean arterial pressure, water balance, and change in cardiac output, and directly with change in total peripheral resistance and change in serum sodium concentration. There was no correlation with change in blood volume or sodium balance.