Normal Hematocrit Levels Research Articles

Angina Pectoris Caused by Pernicious Anemia

Angina Pectoris Caused by Pernicious Anemia

Serum erythropoietin in the diagnosis of polycythaemia and after phlebotomy treatment

Serum erythropoietin (S-Epo) was measured with a radiommunoassay method in 36 patients with polycythaemia vera, 17 patients with secondary polycythaemia and 14 patients with relative polycythaemia. The diagnoses were made without the aid of the S-Epo values. It was found that S-Epo was below the reference range in 34/36 patients with polycythaemia vera (mean 2.1 +/- 1.0 U/l), elevated in all cases of secondary polycythaemia (mean 121.7 +/- 242 U/l) and normal in all but one of the cases with relative polycythaemia (mean 7.0 +/- 2.5 U/l). Previous studies of S-Epo levels in the differential diagnosis of polycythaemia have shown significant differences between the means of the groups but a considerable overlap. After phlebotomy treatment to normal haematocrit levels, the S-Epo levels remained subnormal in most of the polycythaemia vera patients even after 18 months at a haematocrit around 45%. Two patients who had been kept at normal haematocrit for 6 and 7 years both had subnormal S-Epo. We conclude that with an Epo assay method of high sensitivity and specificity it is possible to differentiate between different forms of polycythaemia with a high degree of certainty, even between patients with relative polycythaemia and polycythaemia vera patients. The reason why S-Epo remains low in spite of a normal haematocrit in treated polycythaemia vera patients is not known.

The accuracy of pulse oximetry at two haematocrit levels.

The object of this study was to investigate the influence of haematocrit on the accuracy of pulse oximetry. Seven Swedish land race rabbits were studied. The oxygen saturation of haemoglobin was decreased step-wise using increasing fractions of nitrogen to the inspiratory gas. One pulse oximeter probe was attached on the front leg and another probe directly over the common carotid artery. The pulse oximeter readings (SpO2) were compared with simultaneous oxygen saturation analysis (SaO2) by a haemoximeter. The pulse oximeter measurements were performed at the haematocrit levels of approximately 40% and 11%, respectively. We found a good correlation between SpO2 and SaO2 in a wide range of the oxygen saturation, i.e. SaO2 26-100%. After haemodilution the correlation was improved in the range 86-100%, but not in the range 26-85%. No correlation between SpO2 and SaO2 was found when the sensor was attached directly over the artery during normal haematocrit levels. After haemodilution a better correlation was however obtained. These results indicate that the accuracy of pulse oximetry is dependent on the haematocrit level.

Multicenter study of recombinant human erythropoietin in correction of anemia in rheumatoid arthritis

purpse: To administer recombinant erythropoietin to patients with rheumatoid arthritis who had significant anemia, while monitoring hematologic and rheumatologic clinical responses as well as potential toxicity. patients and methods: Seventeen patients with rheumatoid arthritis from five rheumatology care settings were studied. The patients had initial hematocrits of 34% or less and stable clinical status, and were not being treated with second-line drugs or corticosteroids. An 8-week randomized double-blind study involving various dosages of recombinant erythropoietin, as well as placebo, was followed by a 24-week open-label study in which dosage could be titrated to achieve a normal hematocrit. results: In the 8-week randomized study, four of 13 patients who received injections of recombinant erythropoietin showed a hematologic response, arbitrarily defined as at least a 6-unit increase in hematocrit. None of four placebo-treated patients showed a meaningful hematologic response. All 11 patients who completed the subsequent 24-week open-label study reached a normal hematocrit level at some time during the study, and 10 of 11 showed an increase of hematocrit 6 units or greater. At least one adjustment, i.e., an increase, decrease, or omission of the erythropoietin dosage, was required in all patients to maintain the hematocrit at a target range of 35% for women or 40% for men. Meaningful changes were not seen in patients' capacity to perform activities of daily living or pain levels during either the 8-week randomized study or the 24-week open-label study. No adverse effects were associated with recombinant erythropoietin therapy. conclusion: Patients with rheumatoid arthritis showed excellent hematologic responses to recombinant erythropoietin, without toxicity, during careful monitoring for appropriate dosage adjustment, although a meaningful change in rheumatologic clinical status was not seen.

Recombinant Human Erythropoietin Treatment May Improve Quality of Life and Cognitive Function in Chronic Hemodialysis Patients

Medical, psychological, and social adaptation (quality of life) as well as cognitive function were studied in 15 chronic stable hemodialysis patients before the onset of treatment with recombinant human erythropoietin (r-HuEPO), 1 month after stabilization of normal hematocrit levels, and 10 to 15 months after treatment onset. After r-HuEPO treatment, subjects had significantly higher hematocrits, markedly improved energy levels, and marginally improved global health. r-HuEPO treatment was also associated with progressively decreased levels of subject mood disturbance and dialysis-related stresses. Subjects had no increased participation in paid employment and only minimally increased participation in social and leisure activities at posttreatment data points. There was no significant improvement in cognitive function after treatment. r-HuEPO treatment appears to be associated with higher energy levels, significant psychological benefits, and minimal improvements in social adaptation. The effects on cognitive function merit further study.

Effects of contrast media on endothelial cell monolayers under controlled flow conditions

To compare the biocompatibility of nonionic and ionic intravascular contrast media in a more physiologic in vitro system, key aspects of blood flow through a microvessel were simulated. Toward this end, monolayers of endothelial cells placed in a specially designed flow chamber, real-time imaging of the monolayers by brightfield and phase videomicroscopy, and real-time imaging and computer-aided quantitation at normal hematocrit levels of platelet adhesion/aggregation to sites of monolayer injury by means of epifluorescence videomicroscopy were used. At a concentration in culture medium of 20% by volume, it was found that monolayer morphology was least altered by iohexol when compared with diatrizoate and ioxaglate; monolayer production of prostacyclin was enhanced (p < 0.001) by ioxaglate compared with saline controls; and at a concentration in citrated blood of 20% by non-red-cell volume, platelet adhesion/aggregation was reduced by all 3 contrast agents in the order diatrizoate > ioxaglate > iohexol.

Effects of reductions in hemoglobin-oxygen affinity and hematocrit level on oxygen consumption and acid-base state in fetal lambs

To determine whether the high oxygen affinity of fetal blood, compared with that of the adult, is advantageous to the fetus during fetal anemia we studied 16 chronically catheterized fetal lambs. Half of the lambs had hemoglobin-oxygen affinity reduced acutely by isovolemic exchange transfusion with fresh adult whole blood; the other half served as controls. In both groups of fetuses, we measured fetal oxygen delivery, oxygen consumption, and acid-base state at normal fetal hematocrit levels and during reductions in the hematocrit level of 30% (moderate anemia) and 60% (severe anemia) produced by isovolemic exchange transfusions with plasma. At normal fetal hematocrit levels, reductions in hemoglobin-oxygen affinity had no effect on fetal oxygen consumption or acid-base state. During moderate anemia, fetal oxygen delivery decreased in both series of fetuses, but oxygen consumption and base excess fell only in those fetuses whose circulations contained adult hemoglobin. During severe anemia, oxygen consumption and base excess decreased in both groups of fetuses, although these changes were more pronounced in fetuses with adult hemoglobin than in those with fetal hemoglobin. Our data indicate that, even though a high hemoglobin-oxygen affinity may not be essential to a healthy fetus, it is critical for normal metabolism in a fetus subjected to a hypoxic stress such as anemia.

10% Silver nitrate solution for topical treatment in scalding

The effects of coagulation therapy using a 10% silver nitrate solution is studied on 13 children with scalds averaging 40% of the body surface. The main advantages are immediate pain relief, open wound treatment and stability of the circulatory system. The stable general condition of the patients is illustrated by the fluid balance, by the normal levels of hemoglobin, hematocrit, total protein, and sodium. The potential disadvantages are the risk of infection underneath the crust and the occasional delay in introducing surgical treatment as a result of incorrect initial clinical assessment of the depth of the burn.

Gentamicin pharmacokinetics: effect of aging in patients with normal renal function.

The effects of aging on gentamicin total-body clearance, volume of distribution, and half-life were examined in 173 febrile patients with gram-negative infections. All had normal renal function, normal hematocrit levels, near-ideal body weights, and were not receiving concurrent penicillin therapy. In the 51 patients who were 20-39 years old, the mean clearance of gentamicin was 1.29 ml/min/kg, the volume of distribution was 0.23 l/kg, and the half-life was 2.2 hours. In the 59 patients 40-59 years old, these values were 1.35 ml/min/kg, 0.27 l/kg, and 2.1 hours; in the 63 patients 60-79 years old, they were 1.31 ml/min/kg, 0.26, and 2.4 hours. No significant difference was observed for any of the measures among the three age groups (P less than 0.05, analysis of variance). Linear regression revealed poor correlations between the individual measures and age. Since there is no change in gentamicin pharmacokinetics with aging, dosages do not need to be changed arbitrarily for older patients who have normal renal function.

Adult Respiratory Distress Syndrome

Treatment of the adult respiratory distress syndrome requires an understanding of the current concepts of the pathogenesis of this syndrome. The clinical features and pathophysiology are briefly discussed. Differential diagnosis requires the exclusion of pulmonary infection and left heart failure. Therapy is aimed at correction of the associated initiating disease process and the maintenance of tissue oxygenation. The latter requires increased inspired oxygen concentration, maintenance of an adequate cardiac output, and maintenance of a normal hematocrit level and body temperature. The therapeutic role of intravenous albumin, diuretics, and steroids in this syndrome is still controversial. Currently accepted modalities for improving oxygenation, when oxygen by face mask proves inadequate, include intubation and ventilation with postiive end-expiratory pressure. Other promising technics for improving oxygenation which do not require intubation are continuous positive airway pressure applied by face mask, continuous negative chest wall pressure, and alterations in posture. The long-term prognosis in survivors appears to be good, with only mild residual pulmonary functional abnormalities.

Selection for hematocrit percent in the house mouse.

Two selection experiments were designed to change hematocrit percent. In the first experiment the mice were measured at 60 days and elevated hematocritis were achieved in the first generation with no further response. In the second experiment hematocritis were taken at 100 days and two-way response continued for three generations after which the difference between the high and low lines remained constant. Realized heritability was 71-97 percent in the first generation in one experiment and 24-30 percent for three generations in the second. These compare to an estimate of the degree of genetic determination based on 21 inbred strains of 40 percent. The evidence based on the selection experiments and crosses between inbred strains indicates that few genes are involved in the genetic control of normal hematocrit levels found within inbred strains of mice. The realtionship between hematocrit level and systolic blood pressure suggested by other studies was not a consistent finding in our studies.

Spurious (relative) polycythemia: A nonexistent disease

Blood volume measurements and clinical status were compared in two groups of subjects with a normal measured red cell mass, but with varying hematocrit values. In our series of seventy-five men, thirty-two met the criteria of “spurious” or “relative” polycythemia with an elevated hematocrit exceeding 52 per cent, whereas forty-three others had hematocrit values within the normal range. Several types of alteration in red cell and plasma volumes that could account for the polycythemic picture were found in the group with a high hematocrit value. Diminution in plasma volume or reduction of the body to venous hematocrit ratio consistent with an alteration in red cell or plasma distribution could be implicated in 15 and 25 per cent of these cases, respectively. A comparable incidence of these alterations was noted in the subjects with normal hematocrit levels. The only distinguishing characteristic in the subjects with elevated hematocrit values was the finding of a combination of a high normal red cell mass with a low normal plasma volume. This physiologic variation appeared to be responsible for the hematocrit elevation in 40 per cent of cases which fit the criteria for “relative” polycythemia. The subjects with high hematocrit values did not have a greater incidence of abnormal clinical features when compared to those with the normal hematocrit levels. There was higher incidence of mild hypertension, although the presence of an elevated blood pressure did not correlate directly with the height of the hematocrit. We have chosen the term “spurious polycythemia” to designate those subjects who have a chronic elevation in venous hematocrit in the presence of a normal measured red cell mass, whether or not they manifest cardiovascular disease or other clinical abnormalities. This term is consistent with the heterogeneity of findings in this population of patients in that it avoids reference to any specific mechanism underlying the hematocrit elevation and is least likely to confer the idea of a specific disease process or syndrome.

An Erythrocyte Defect in Splenectomized X‐Irradiated Mice Restored with Spleen Colony Cells

Summary The profound anaemia previously seen in splenectomized irradiated LAF1 mice injected with isogenic spleen nodule cells, has been confirmed in two other mouse strains. The anaemia does not invariably cause death, but a slow recovery to normal haematocrit levels occurs in about 80 days.By splenectomy at various times after irradiation, some modification of the severity of the anaemia was achieved, but recovery was not accelerated.Implantation of normal splenic tissues in Millipore filter chambers intraperitoneally failed to modify the severity of the anaemia, but an improvement in the rate of recovery was observed. 59Fe 5‐hour uptake data indicate that spleen nodule cells do not help in the re‐population of erythroid elements of bone marrow, though there is some acceleration of re‐population of spleen as a result of injection of these cells. Both bone marrow cells and normal spleen cells are seen to be more effective than spleen nodule cells in the re‐populating bone marrow.Spontaneous recovery of the bone marrow erythroid population occurs in mice irradiated and injected with spleen nodule cells but an anaemia persists unless the spleen is present.It is concluded that an erythrocyte defect occurs in splenectomized, irradiated, spleen nodule cell‐injected mice — a defect which only slowly recovers.

Transfusion experiments and survival studies in parabiosis intoxication.

Summary(1) Transfusion of the hybrid mouse in parabiosis with a parental strain partner was followed by shunting of blood to the latter. The hybrid mouse was not benefited. (2) When the hybrid mouse was separated from the parental strain partner 10 days after union, the hybrid mouse showed a temporary weight gain, followed by progressive wasting and death. Transfusion of the hybrid mouse to a normal hematocrit level did not alter this course of events. (3) When separation and transfusion of the hybrid were carried out 6 days after parabiosis, there was a greater gain in weight than in nontransfused controls, and a reduction in mortality from 11/12 to 6/8. In both transfused and non-transfused groups survival time was significantly prolonged, compared to hybrid mice remaining in parabiosis. (4) Transfusion of hybrid mice suffering from homologous disease resulted in a reduction of mortality from 8/10 to 6/10 but otherwise the course of the disease was not altered. (5) Parabiosis intoxication, in the strain...