Evidence of cerebral hemodynamic dysregulation in middle-aged APOE ε4 carriers: The PREVENT-Dementia study.

Accumulating evidence suggests vascular dysregulation in preclinical Alzheimer's disease. In this study, cerebral hemodynamics and their coupling with cognition in middle-aged apolipoprotein ε4 carriers (APOEε4+) were investigated. Longitudinal 3 T T1-weighted and arterial spin labelling MRI data from 158 participants (40-59 years old) in the PREVENT-Dementia study were analysed (125 two-year follow-up). Cognition was evaluated using the COGNITO battery. Cerebral blood flow (CBF) and cerebrovascular resistance index (CVRi) were quantified for the flow territories of the anterior, middle and posterior cerebral arteries. CBF was corrected for underlying atrophy and individual hematocrit. Hemodynamic measures were the dependent variables in linear regression models, with age, sex, years of education and APOEε4 carriership as predictors. Further analyses were conducted with cognitive outcomes as dependent variables, using the same model as before with additional APOEε4 × hemodynamics interactions. At baseline, APOEε4+ showed increased CBF and decreased CVRi compared to non-carriers in the anterior and middle cerebral arteries, suggestive of potential vasodilation. Hemodynamic changes were similar between groups. Interaction analysis revealed positive associations between CBF changes and performance changes in delayed recall (for APOEε4 non-carriers) and verbal fluency (for APOEε4 carriers) cognitive tests. These observations are consistent with neurovascular dysregulation in middle-aged APOEε4+.

Hematocrit as a predictor of preoperative transfusion-associated complications in spine surgery: A NSQIP study.

BACKGROUND CONTEXT: Preoperative optimization of medical comorbidities prior to spinal surgery is becoming an increasingly important intervention in decreasing postoperative complications and ensuring a satisfactory postoperative course. The treatment of preoperative anemia is based on guidelines made by the American College of Cardiology (ACC), which recommends packed red blood cell transfusion when hematocrit is less than 21% in patients without cardiovascular disease and 24% in patients with cardiovascular disease. The literature has yet to quantify the risk profile associated with preoperative pRBC transfusion. PURPOSE: To determine the incidence of complications following preoperative pRBC transfusion in a cohort of patients undergoing spine surgery. STUDY DESIGN: Retrospective review of a national surgical database. PATIENT SAMPLE: The national surgical quality improvement program database OUTCOME NEASURES: Postoperative physiologic complications after a preoperative transfusion. Complications were defined as the occurrence of any DVT, PE, stroke, cardiac arrest, myocardial infarction, longer length of stay, need for mechanical ventilation greater than 48 h, surgical site infections, sepsis, urinary tract infections, pneumonia, or higher 30-day mortality. METHODS: The national surgical quality improvement program database was queried, and patients were included if they had any type of spine surgery and had a preoperative transfusion. RESULTS: Preoperative pRBC transfusion was found to be protective against complications when the hematocrit was less than 20% and associated with more complications when the hematocrit was higher than 20%. In patients with a hematocrit higher than 20%, pRBC transfusion was associated with longer lengths of stay, and higher rates of ventilator dependency greater than 48 h, pneumonia, and 30-day mortality. CONCLUSION: This is the first study to identify an inflection point in determining when a preoperative pRBC transfusion may be protective or may contribute to complications. Further studies are needed to be conducted to stratify by the prevalence of cardiovascular disease.

Low hematocrit levels: a risk factor for long-term outcomes in patients requiring prolonged mechanical ventilation after cardiovascular surgery. A retrospective study.

While low-risk patients who undergo elective surgery can tolerate low hematocrit levels, the benefits of higher hematocrit levels might outweigh the risk of transfusion in high-risk patients. Therefore, this study aimed to evaluate the effects of perioperative hematocrit levels on mortality in patients requiring prolonged mechanical ventilation (PMV) after a cardiovascular surgery. This single-center retrospective cohort study was conducted on 172 patients who underwent cardiovascular surgery with cardiopulmonary bypass or off-pump coronary artery bypass grafting and required PMV for ≥72 hours in the intensive care unit (ICU) from 2008 to 2012 at the Yokohama City University Medical Center in Yokohama, Japan. Patients were classified according to hematocrit levels on ICU admission: high (≥30%) and low (<30%) groups. Of 172 patients, 86 were included to each of the low-hematocrit and high-hematocrit groups, with median hematocrit levels (first to third quartiles) of 27.4% (25.4%-28.7%) and 33.0% (31.3%-35.5%), respectively. The difference in survival rates was significant between the two groups using the log-rank test (HR 0.55, 95% CI 0.32 to 0.95, p=0.033). Cox regression analysis revealed that ≥30% increase in hematocrit levels on ICU admission was significantly associated with decreased long-term mortality (HR 0.40, 95% CI 0.20 to 0.80, p=0.0095). Lower hematocrit levels on ICU admission was a risk factor for increased long-term mortality, and higher hematocrit levels might outweigh the risk of transfusion in patients requiring PMV after a cardiovascular surgery.

Packed red blood cell transfusion associates with acute kidney injury after transcatheter aortic valve replacement.

BACKGROUND: Acute kidney injury after cardiac surgery significantly associates with morbidity and mortality. Despite not requiring cardiopulmonary bypass, transcatheter aortic valve replacement patients have an incidence of post-procedural acute kidney injury similar to patients who undergo open surgical aortic valve replacement. Packed red blood cell transfusion has been associated with morbidity and mortality after cardiac surgery. We hypothesized that packed red blood cell transfusion independently associates with acute kidney injury after transcatheter aortic valve replacement, after accounting for other risk factors. METHODS: This is a single-center retrospective cohort study of 116 patients undergoing transcatheter aortic valve replacement. Post-transcatheter aortic valve replacement acute kidney injury was defined by Kidney Disease: Improving Global Outcomes serum creatinine-based criteria. Univariate comparisons between patients with and without post-transcatheter aortic valve replacement acute kidney injury were made for clinical characteristics. Multivariable logistic regression was used to assess independent association of packed red blood cell transfusion with post-transcatheter aortic valve replacement acute kidney injury (adjusting for pre-procedural renal function and other important clinical parameters). RESULTS: Acute kidney injury occurred in 20 (17.2%) subjects. Total number of packed red blood cells transfused independently associated with post-procedure acute kidney injury (OR = 1.67 per unit, 95% CI 1.13-2.47, P = 0.01) after adjusting for pre-procedure estimated glomerular filtration rate (OR = 0.97 per ml/min/1.73m2, 95% CI 0.94-1.00, P = 0.05), nadir hemoglobin (OR = 0.88 per g/dL increase, CI 0.61-1.27, P = 0.50), and post-procedure maximum number of concurrent inotropes and vasopressors (OR = 2.09 per inotrope or vasopressor, 95% CI 1.19-3.67, P = 0.01). CONCLUSION: Packed red blood cell transfusion, along with post-procedure use of inotropes and vasopressors, independently associate with acute kidney injury after transcatheter aortic valve replacement. Further studies are needed to elucidate the pathobiology underlying these associations.

Postnatal Paraclinical Parameters Associated to Occurrence of Intracerebral Hemorrhage in Preterm Infants.

Intracerebral hemorrhage (ICH) is the most frequent complication in postnatal development of preterm infants. The purpose of the present work is the statistical evaluation of seven standard paraclinical parameters and their association to the development of ICH. Clinical records of 265 preterm infants with gestational age (GA) 23 to 30 weeks were analyzed. According to ICH status, patients were divided into control (without ICH) and affected (with ICH) groups. Mean values of paraclinical parameters at each week of gestation were compared. Different ICH grades, periods before and after ICH were considered separately. Lower hematocrit, SaO2, and pH were statistically significant for preterm infants with 23 to 30 weeks GA and diagnosis of ICH relative to infants without ICH. Additionally, for preterm infants with 27 to 30 weeks GA, higher C-reactive protein, as well as lower values of thrombocytes were associated with the occurrence of ICH. Preterm infants with 23 to 26 weeks GA showed C-reactive protein values similar to those in the group without ICH and lower levels of thrombocytes after bleeding. Significant differences in paraclinical parameters between preterm infants with and without ICH may constitute useful indicators for closer clinical observation of preterm infants at risk of ICH.

Therapeutic plasma exchange in a tertiary care center: 185 patients undergoing 912 treatments - a one-year retrospective analysis.

BACKGROUND: Therapeutic plasma exchange (TPE) is increasingly used throughout the world. Although the procedure itself is fairly standardized, it is yet unknown how the underlying disease entities influence the key coordinates of the treatment. METHODS: Retrospective chart review. The treatment indications were clustered into four categories. Data are presented as median and interquartile (25-75%) range [IQR]. RESULTS: Within 1 year, 912 TPE treatments were performed in 185 patients (90 female, 48.6%). The distribution of the treatment numbers to the pre-specified disease categories were as follows: transplantation (35.7%), neurology (31.9%), vasculitis and immunological disease (17.3%), and others including thrombotic microangiopathy (8.1%), critical care related diseases (5.4%), hematology [multiple myeloma] (1.1%), and endocrine disorders (0.5%). The calculated plasma volume was significantly higher in patients with vasculitis and immunological diseases (3984 [3433-4439] ml) as compared to patients treated for transplant related indications (3194 [2545-3658] ml; p = 0.0003) and neurological diseases (3058 [2533-3359] ml; p < 0.0001). This was mainly due to the differences in the hematocrit which was 30.5 [27.0-33.6] % in the vasculitis/immunological disease patients and 40.2 [37.5-42.9] % in the neurological patients; p < 0.0001. Interestingly, treatment time using a membrane based technology was significantly longer than TPE using a centrifugal device 135.0 [125.0-140.0] min vs. 120.0 [112.5-135.0] min. Furthermore, the relative exchanged plasma volume was significantly lower in the treatment of vasculitis and immunological diseases as compared to treatments of transplant related indications and neurological diseases. CONCLUSION: Patients with low hematocrit and high body weight do not receive the minimum recommended dose of exchange volume. Centrifugal TPE allowed faster plasma exchange than membrane TPE.

Renal and hematologic side effects of long-term intravenous immunoglobulin therapy in patients with neurologic disorders.

INTRODUCTION: For patients receiving intravenous immunoglobulin (IVIg), renal and hemolytic side effects are well recognized. However, there are very few data on the effects of chronic IVIg therapy. METHODS: We retrospectively analyzed laboratory data on 166 patients who received IVIg for 12 months with a dose range of 0.441-2.58 g/kg/month, measuring changes in hematocrit and glomerular filtration (GFR) rates at 6 and 12 months. RESULTS: Of the 2,232 infusions, there were no incidents of clinical hemolysis. However, after 12 months of treatment, 21% of patients had a ≥3-g/dl decline in hematocrit and 10% had a ≥20% decline in GFR. DISCUSSION: No clinically significant hemolysis was observed in patients receiving chronic IVIg therapy. However, a significant number of patients had a decline in hematocrit and/or GFR while on therapy. This emphasizes the need for observation of hematologic and renal function in patients treated with chronic IVIg. Muscle Nerve 56: 1173-1176, 2017.

Bronchoalveolar Lavage Fluid Cellular and Haematological Changes in Different Types of Caprine Pneumonia.

Goats in the tropics are often reared under the traditional extensive and semi-intensive management systems. These and other factors influence the pattern of pneumonia complex in goats. We investigated the bronchoalveolar lavage fluid (BALf) cellular changes and haematological response in different types of caprine pneumonia in Nigeria. Haematological indices and BALf cells were analysed from 300 goats randomly selected from 700 goats comprising different breed, age and body scores. The pneumonia status was well characterised using standard pathological tools. Data is summarized as Mean ± SEM and compared using non-parametric statistics at 5% significance. There was leukocytosis in the pneumonic animals. The overall lavage recovery rate was 55.5%. The differences in Haemoglobin concentration, and Lymphocyte-Neutrophil ratio were significant (p<0.05). BALf changes in the neutrophil, macrophage and eosinophil counts were significantly different (p<0.05). The diagnostic features including increased percentage neutrophils, Macrophage-Neutrophil ratio and eosinophils observed in BAL were reliable and also correlated positively to the pathological findings. BAL should be considered a component of the diagnostic approach to caprine pneumonia complex, as it may accurately aid diagnosis and identification of the causal organisms.

Antenatal depression and hematocrit levels as predictors of postpartum depression and anxiety symptoms.

The aim of this study is to delineate the risk factors of antenatal depression and its consequences, including postnatal depression, and to examine whether the hematocrit (Hct) is associated with maternal depression. The Edinburgh Postnatal Depression Scale (EPDS), Spielberger's State Anxiety Inventory (STAI), Kennerley and Gath Maternity Blues Assessment Scale (KGB), Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HAMD) were assessed at the end of term (T1) and 2-3 days (T2) and 4-6 weeks (T3) after delivery in 126 women with and without antenatal depression. The Hct was measured at T1. Antenatal depression was significantly predicted by lifetime depression and premenstrual syndrome and less education. Antenatal depression was not associated with obstetric or neonatal outcomes. Antenatal depression symptoms strongly predict depression and anxiety symptoms at T2 and T3. The EPDS, KGB, STAI and BDI, but not the HAMD, scores, were significantly lower at T3 than before. The incidence of depression significantly decreased from T1 (23.8%) to T2 (7.8%) and T3 (5.3%). T1 Hct values significantly predicted the T3 postnatal EPDS, STAI, KGB and BDI scores. Delivery significantly improves depression and anxiety symptoms. Increased Hct in the third trimester is a biomarker of postpartum depression and anxiety symptoms.

Early neonatal bilirubin, hematocrit, and glucose-6-phosphate dehydrogenase status.

OBJECTIVE: To document the patterns of bilirubin and hematocrit values among glucose-6-phosphate dehydrogenase (G6PD)-deficient and G6PD-normal Nigerian neonates in the first week of life, in the absence of exposure to known icterogenic agents. METHODS: The G6PD status of consecutive term and near-term neonates was determined, and their bilirubin levels and hematocrits were monitored during the first week of life. Infants were stratified into G6PD deficient, intermediate, and normal on the basis of the modified Beutler's fluorescent spot test. Means of total serum bilirubin (TSB) and hematocrits of the 3 groups of infants were compared. RESULTS: The 644 neonates studied comprised 353 (54.8%) boys and 291 (45.2%) girls and 540 (83.9%) term and 104 (16.1%) near-term infants. They consisted of 129 (20.0%) G6PD-deficient, 69 (10.7%) G6PD-intermediate, and 446 (69.3%) G6PD-normal neonates. The G6PD-deficient and G6PD-intermediate infants had higher mean TSB than their G6PD-normal counterparts at birth and throughout the first week of life (P < .001). Mean peak TSB levels were 14.1 (9.48), 10.2 (3.8), and 6.9 (3.3) mg/dL for G6PD-deficient, G6PD-intermediate, and G6PD-normal neonates, respectively. Peak TSB was attained on approximately day 4 in all 3 groups, and trends in TSB were similar. Mean hematocrits at birth were similar in the 3 G6PD groups. However, G6PD-deficient and -intermediate infants had higher declines in hematocrit, bilirubin levels, and need for phototherapy than G6PD-normal infants (P < .001). CONCLUSIONS: The G6PD-deficient and G6PD-intermediate neonates had a higher risk of neonatal hyperbilirubinemia and would therefore need greater monitoring in the first week of life, even without exposure to known icterogenic agents.

Erythrocyte Osmotic Fragility and Excitability Score in Rabbit fed Hibiscus Sabdariffa in Graded Level.

This study was conducted for 10 weeks with the aim of investigating the erythrocyte membrane integrity as measured by erythrocyte osmotic fragility and excitability scores of rabbits fed graded level of Hibiscus sabdariffa calyx (HSC). Twenty weaners' rabbit of both sexes were used for the study and were placed on four experimental diets which contain the following percentages of HSC 0 %, 25 %, 50 %, 75 %, as feed additive and were added at 0 g, 62.5 g, 125 g, 187.5 g designated as T1, T2, T3 and T4 experimental diets. Excitability scores were measured weekly as described by Voisnet et al. (1997). At the end of the experiment, the rabbits were slaughtered by severing the jugular vein. A Blood sample (2 ml) was collected from each rabbit into sampled bottles, containing the Na EDTA as anticoagulant for hematological analysis. Packed cell volume (PCV) Haemoglobin concentration (Hb), Total red blood cell (RBC) count, Total leukocyte count as well as differential leukocyte was determined using standard method. The percentage haemolysis recorded at 0.3 % to 0.8 % was significantly (P < 0.05) higher in rabbits in T1 compared to the remaining 3 diets. The result of excitability score shows that rabbit on diet 1 and 2 had a lower value which was significantly (P < 0.05) lower than rabbits on diets 3 and 4 with a value of 65.5 ± 5.0 and 70.00 ± 5.50 % respectively. In conclusion this study demonstrated for the first time that chronic administration of HSC improves haematological parameters, brain mood and function as well as maintaining erythrocyte membrane integrity.

Association between hematocrit in late adolescence and subsequent myocardial infarction in Swedish men.

BACKGROUND: Hematocrit is an independent predictor of cardiovascular risk in middle and old age, but whether hematocrit is also a predictor at younger ages is presently not known. In this study, we examined whether hematocrit measured in adolescence was associated with the risk of myocardial infarction later in life. METHODS: During Swedish national conscription tests conducted between 1969 and 1978, the hematocrit was measured in 417,099 young Swedish men. The cohort was followed for subsequent myocardial infarction events through December 2010. Associations between hematocrit and myocardial infarction were accessed using Cox regression models. RESULTS: During a median follow-up period of 36 years, 9322 first-time myocardial infarctions occurred within the study cohort. After adjusting for relevant confounders and potential risk factors for myocardial infarction, men with a hematocrit≥49% had a 1.4-fold increased risk of myocardial infarction compared with men with a hematocrit≤44%. This relationship was dose dependent (p<0.001 for trend) and remained consistent throughout the follow-up period. CONCLUSIONS: In this cohort of young Swedish men, hematocrit was associated with the risk of myocardial infarction later in life after controlling for other coronary risk factors. The study findings indicate that hematocrit may aid future risk assessments in young individuals.

Policitemia neonatal e hiperviscosidad / Neonatal polycythemia and hyperviscosity

Se define policitemia neonatal al aumento anormal de glóbulos rojos traducido por un hematocrito venosocentral mayor o igual a 65% durante los primeros días de vida. La elevación del hematocrito se asocia en algunos casos con hiperviscosidad sanguínea que produce alteraciones en el flujo sanguíneo de varios órganos.

Relation of anemia at discharge to survival after acute coronary syndromes.

Two-year survival rate was assessed among 1,038 patients who had acute coronary syndromes that were classified by discharge hematocrit values as normal (>39%, n = 360, 34.7%), mildly anemic (33.1% to 39%, n = 430, 41.4%), or moderately/severely anemic (< or = 33%, n = 248, 23.9%). Worsening anemia was associated with a decreased 2-year survival rate (normal 95.8%, mild anemia 91.2%, moderate/severe anemia 81.5%, p < 0.001). In multivariable analyses, adjusted hazard ratios for all-cause mortality were 1.57 (95% confidence interval 0.82 to 2.96) for mild anemia and 2.46 (95% confidence interval 1.25 to 4.85) for moderate/severe anemia.

Effect of altitude on second-generation blood tests to detect erythropoietin abuse by athletes.

BACKGROUND AND OBJECTIVES: ON- and OFF-model scores derived from blood parameters sensitive to erythropoiesis have been shown to be a useful tool to identify athletes who are currently injecting erythropoietin to enhance performance or those who have recently stopped doing so. We investigated changes in blood parameters and model scores during and after exposure to terrestrial and simulated altitudes. DESIGN AND METHODS: We retrospectively evaluated changes in hematologic data collected from 19 elite cyclists who lived and trained 2690 m above sea level for 26-31 days, from six elite Kenyan runners who lived 2100 m above sea level but descended to compete at sea level competitions, and from 39 well-trained subjects who resided at sea level but slept at a simulated altitude of 2650-3000 m for 20-23 days of either consecutive or intermittent nightly exposure. RESULTS: Upon ascent to a terrestrial altitude, ON- and OFF-model scores increased immediately, mainly because of an increase in hemoglobin concentration. Scores had not returned fully to baseline three weeks after return to sea level, because of the persistence of the raised hemoglobin concentration for the ON and OFF scores and a fall in reticulocyte percentage for OFF scores. Effects were smaller or negligible for simulated altitude. For Kenyan runners, ON- and OFF-model scores decreased within seven days of descent to sea level. INTERPRETATION AND CONCLUSIONS: Our results reinforce the notion that caution should be exercised when interpreting blood results from athletes who have recently been exposed to either terrestrial or simulated altitude, and appropriate allowance should be made for the effect of altitude on blood model scores.

Valores de referencia de hemoglobina y hematocrito en una poblacion laboral colombiana / Reference values of hemoglobin and hematocrit in a Colombian worker's community

Problema: obtener valores de referencia de cianometahemoglobina (ciano-Hb), oxihemoglobina (HbO) y hematocrito para población laboral activa, afiliada al Seguro Social y vinculada a empresas del Valle de Aburra y del cercano oriente antioqueño. Metodología: estudio descriptivo, transversal y prospectivo. Se diseñaron sendas muestras con criterios estadísticos y demográfíco-epidemiológicos: 415 personas en Aburra y 412 en Oriente (total 827). Son trabajadores activos y aparentemente sanos. Se midieron ciano-Hb y hematocrito con equipo automático, Hb02 con equipo EQM Research Inc, Resultados: a) cianoHb, Hb02 y hematocrito difieren significativamente por región (mayores en Oriente, lugar más alto) y por género, pero no por edad. En Aburra, los 193 hombres tienen cianoHb de 16,13 g/dL (intervalo confianza 95 por ciento: 15,89-16,36) y 222 mujeres poseen 13,86 g/dL (13,65- 14,07); en Oriente, los 197 hombres poseen 16,49 g/dL (16,27-16,71) y 215 mujeres 14,41 g/dL (14,20-14,62). b) Hay alta correlación lineal entre ciano-Hb y Hb02 (r= 0,913), con ecuaciones: ciano-Hb = 0,877 + 1,128 (HbO;); HbO;, = 1,538 + 0,734 ciano-Hb). c) Existe alta correlación entre ciano-Hb y hematocrito (r= 0,959), así: ciano-Hb= 0,216 + 0,336 (hematocrito); hematocrito= 4,297 + 2,737 (ciano-Hb). d) Hay alta correlación entre HbO;, y hematocrito (r= 0,896), así: Hb0;= 1,045 + 0,253 (hematocrito); hematocrito= 6,304 + 3,122 (HbO;). e) Los valores de ciano-Hb y hematocrito obtenidos en esta población laboral difieren de los informados para población general, f) Es adecuado usar valores de ciano-Hb para obtener hematocrito y HbO2, así como emplear HbO2 para calcular ciano-Hb y hematocrito.

Modificaciones del fibrinógeno en la trombosis en la altura / Fibrinogen changes in the high altitude thrombosis

Los estudios de rutina sobre la hemostasis no son los más indicados para anunciar en una fase precoz el establecimiento de una trombosis. Las anormalidades en el mecanismo de la coagulación de la fibrinolisis o de las plaquetas, están lejos de ser parámetros específicos directos que anuncie un riesgo de Trombosis en un paciente determinado. En los resultados de fibrinógeno y la Fibrinólisis, realizados en nuestro medio, se ha considerado a la hipoxia, como componente importante inductor de la Eritrocitosis en ciertas situaciones patológicas y que este factor agravaría el desarrollo de la trombosis en el nativo de la altura, pero estudios anteriores sobre este tema con relación a la función plaquetaria (Caen, J., Drovet, L. Ergueta J., Rodriguez A. 1972-1977) demostraron no ser evidentes. Realizamos un estudio protocolizado reciente, en 50 individuos nativos de la altura, cuyas edades fluctúan entre los 18 y 20 años de edad, en ellos se provocó una hipoxia local (venostasia) durante 10 minutos, con la finalidad de determinar los siguientes parámetros: Fibrinógeno, Fibrinólisis, Hematocrito y Grupos Sanguíneos, este último dato sirvió para relacionar la frecuencia de trombósis y valor de ésta proteína en los del grupo "O". La Fibrinólisis en ambos sexos nos demostró una aceleración en tiempo de 2 horas 15 minutos con relación a los de la costa que es >=3 horas. En el Hematocrito y la Hemoglobina encontramos que las mujeres del grupo sanguíneo "B" muestran una variación significativa en relación a los otros grupos sanguíneos. Los varones del grupo sanguíneo "A" y "O" mostraron también variaciones importantes.

Acción de los cambios hormonales sobre los valores hematimétricos, hemostasia, coagulación y fibrinolisis / Intervention of the hormonal changes in hematimetric hemostatic, coagulation and fibrinolysis values

Determinamos la acción de los cambios hormonales, progesterona y estrogeno sobre la hematopoyesis, hemostasia, coagulacion y fibrinolisis, en mujeres nativas de la altura. Se estudio 50 casos, con se respectiva ficha clinica, antes y despues de ciclo menstrual. Se correlacionaron factores geneticos (Grupos, sanguineos: A, B, O). Los sujetos del grupo O y AB, mostraron disminucion significativa de sus reticulocitos (p<0.001). En cambio, los del grupo A y B, aumentaron el numero de estas celulas (p<0.001). Ademas en el grupo sanguineo O, se observo que hacen uso de las reservas de Fe (Protoporfirina), a diferencia de los otros grupos. Referente a la hemostasia, el estudio cuantitativo y cualitativo (numeracion, agragacion y fragilidad capilar), mostraron una disminucion significativa (p<0.05 - p<0.001). En la coagulacion se observo una disminucion significativa en cuanto a la actividad protrombinica y del tiempo de tromboplastina parcial, (p<0.005 y 0.0001). Esto expliacria los sangrados menstruales prolongados y abundantes. Finalmente, la fibrinolisis tuvo valores superiores a 3 horas, en relacion a os valores normales (12 hrs. 30 min). De este trabajo concluimos, que los factores geneticos influyen en la Eritropoyesis, la Hemostasia, Coagulación y Fribrinolisis, en los sujetos de la altura, lo que nos permitira continuar estos estudios, referentes a la Eritrocitosis de nuestro medio.