Erythrocyte morphology in women with severe preeclampsia and eclampsia. Preliminary observations with scanning electron microscopy

Membrane Lesions and Reduced Life Span of Red Blood Cells in Preeclampsia as Evidenced by Atomic Force Microscopy

Preeclampsia (PE) presents with maternal de novo hypertension and significant proteinuria and is one of the leading causes of maternal and perinatal morbidity and mortality with unknown etiology. The disease is associated with inflammatory vascular response and severe red blood cell (RBC) morphology changes. This study examined the nanoscopic morphological changes of RBCs from PE women versus normotensive healthy pregnant controls (PCs) and non-pregnant controls (NPCs) applying atomic force microscopy (AFM) imaging. The results revealed that the membrane of fresh PE RBCs differed significantly from healthy ones by the presence of invaginations and protrusions and an increased roughness value (R_rms) (4.7 ± 0.8 nm for PE vs. 3.8 ± 0.5 nm and 2.9 ± 0.4 nm for PCs and NPCs, respectively). PE-cells aging resulted in more pronounced protrusions and concavities, with exponentially increasing R_rms values, in contrast to the controls, where the R_rms parameter decreased linearly with time. The R_rms, evaluated on a 2 × 2 µm² scanned area, for senescent PE cells (13 ± 2.0 nm) was significantly higher (p < 0.01) than that of PCs (1.5 ± 0.2 nm) and NPCs (1.9 ± 0.2 nm). Furthermore, the RBCs from PE patients appeared fragile, and often only ghosts were observed instead of intact cells at 20-30 days of aging. Oxidative-stress simulation on healthy cells led to RBC membrane features similar to those observed for PE cells. The results demonstrate that the most pronounced effects on RBCs in PE patients are related to impaired membrane homogeneity and strongly altered roughness values, as well as to vesiculation and ghost formation in the course of cell aging.

Hemostatic dysfunction with acute fatty liver of pregnancy

OBJECTIVE

To estimate the frequency of disseminated intravascular coagulation (DIC); elucidate the genesis of hemostatic dysfunction; and characterize associated hemolysis in women with acute fatty liver of pregnancy.

METHODS

Hemostatic function was measured in 51 women. Disseminated intravascular coagulation was assessed using the International Society of Thrombosis and Haemostasis DIC score. Hepatic and hemostatic function was quantified with measurement of fibrinogen, fibrin-fibrinogen split products, cholesterol, and coagulation testing. As a comparison of fibrinogen synthesis, these women were compared with 25 women with placental abruption. Hemolysis was assessed indirectly by quantification of reticulocytosis and nucleated red blood cells with determination of erythrocyte morphotypes.

RESULTS

Eighty-percent of women were classified as having unequivocal DIC (mean score 5.9±1.8) at delivery, which persisted 4-5 days postpartum. Fibrinogen regeneration with placental abruption was rapid, whereas it remained depressed for 4-5 days with acute fatty liver of pregnancy; fibrin-fibrinogen split products were also cleared more rapidly after abruption than women with acute fatty liver (P<.001 for interaction for both using random effects modeling). Kaplan-Meier survival analysis of fibrinogen recovery to a set point of 280 mg/dL after delivery was also different between the two cohorts (median 1.7 compared with 4.2 days, P=.046). Continuing hepatic dysfunction with acute fatty liver of pregnancy was exemplified by diminished procoagulant production. Reticulocytosis, nucleated red blood cells, and elevated serum bilirubin levels reflected ongoing hemolysis.

CONCLUSIONS

Hemostatic dysfunction with acute fatty liver of pregnancy persists 4-5 days postpartum and results from substantive ongoing DIC in concert with reduced procoagulant synthesis and clinically significant hemolysis.

LEVEL OF EVIDENCE

: III.

Susceptibility of red blood cell lipids to in vitro oxidation and antioxidant status in preeclampsia

OBJECTIVE

To investigate susceptibility of red blood cell (RBC) lipids to oxidation and antioxidant status in preeclampsia.

STUDY DESIGN

Twenty-one women with mild preeclampsia, 21 women with severe preeclampsia, and 20 healthy pregnant women were included in this cross-sectional study. Susceptibility of RBC to oxidative stress was determined by measuring RBC-malondialdehyde levels after incubation with hydrogen peroxide. Vitamins E and C, total carotenoids and erythrocyte superoxide dismutase and glutathione peroxidase (GPx) activities and serum total antioxidant capacity (TAC) were determined spectrophotometrically. One-way analysis of variance and correlation analysis were used for statistical analyses.

RESULTS

Compared with the normal pregnant women, susceptibility of RBC to oxidation was enhanced in the mild (p<0.05) and severe (p<0.01) preeclampsia groups, TAC was lower in the mild (p<0.01) and severe (p<0.001) preeclampsia groups. Vitamin C level was decreased in severe preeclampsia and total carotene level was decreased in mild and severe preeclampsia groups (p<0.05). GPx activity was also decreased in the mild (p<0.01) and severe (p<0.05) preeclampsia groups.

CONCLUSION

The results of the present study supported the oxidative stress hypothesis of preeclampsia and it is possible that RBC play a role in the pathophysiology of the disease.

Alpha-hemoglobin-stabilizing protein (AHSP) in hemolysis, elevated liver enzyme, and low platelet (HELLP) syndrome, intrauterine growth restriction (IUGR) and fetal death

OBJECTIVE

Alpha hemoglobin-stabilizing protein (AHSP) inhibits the production of reactive oxygen species in various cells, including erythrocytes. Reduced AHSP can mean reduced protection from stressors. Our objective was to investigate whether AHSP is involved in the response to stress in pregnancy.

STUDY DESIGN

Placentas were collected from normal term pregnancies (n = 10) and pregnancies complicated by HELLP (n = 10), intrauterine growth restriction (IUGR; n = 10) or fetal death (IUFD; n = 6). AHSP messenger RNA (mRNA) and protein were determined using real time quantitative polymerase chain reaction (PCR) and Western blot, respectively. All statistical analyses were performed by using the GraphPad Prism Software. Differences were considered significant at p < 0.05.

RESULTS

Placental AHSP mRNA level in HELLP (4.16E10(-4) +/- 1.77) and IUFD (4.19E10(-4) +/- 3.37) were significantly decreased compared with controls (28.47E10(-4) +/- 14.86; p < 0.01), whereas levels in the IUGR group (7.55E10(-4) +/- 6.4) showed a trend toward being lower but the difference did not reach statistical significance. Western blot analysis results indicate a no significant increase of ASHP protein in the HELLP syndrome group and a significant decrease in the IUFD group compared with controls. There was no significant difference between the IUGR and control groups.

CONCLUSION

ASHP mRNA expression in the placenta is decreased in complicated pregnancies, and it may be involved in the pathogenic mechanisms leading to the adverse pregnancy outcome.

Frequency and significance of schistocytes in TTP/HUS patients at the discontinuation of plasma exchange therapy

INTRODUCTION

Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) is characterized by thrombocytopenia, a microangiopathic hemolytic anemia (presence of schistocytes) and elevated LDH without another likely explanation. Standard of care is daily plasma exchange, which is typically discontinued when the platelet count exceeds 100-150 x 10(9)/L for 2 days. However, residual schistocytosis, the presence of schistocytes at the time of discontinuation of plasma exchange therapy, is often disconcerting. We evaluated the frequency and significance of residual schistocytosis in TTP/HUS patients when the patients' platelet counts returned to normal levels (e.g., 100-150 x 10(9)/L).

METHODS

Retrospective review in our institution from 01/1999-03/2004 of all patients treated with plasma exchange for TTP/HUS with at least 2 months of follow-up for relapse was completed. Patients were excluded if the clinical course was complicated by HIV, stem cell/bone marrow and solid organ transplant, pregnancy and auto-immune disease. Schistocytes were documented on day of presentation and on the day the platelet count reached 150 x 10(9)/L. Grading scale (using 100 x objective-a high power field, with approximately 100 red blood cells per field) for schistocytes was as follows: rare for 1 schistocyte per every other other field, 1+ for 1-5%, 2+ for 6-15%, and 3+ for >15%. The frequency of schistocytes was compared to frequency of relapse within 2 months, using Fisher's exact test.

RESULTS

We identified 57 patients with TTP/HUS who received plasma exchange therapy. Of these patients, 12 did not have a follow-up microscopic examination of a peripheral blood smear at discontinuation of plasma exchange therapy and were excluded from further analysis. Of the remaining 45 patients, 16 had residual schistocytosis (35.6%). There was no statistically significant difference in relapse rate with or without residual schistocytosis (P = 1.00, Fisher's Exact test, 2 sided).

CONCLUSIONS

In this study, we found that the presence of residual schistocytosis is common (35.6%). The presence of residual schistocytosis, however, was not predictive of relapse.

Morphologic diagnosis of thrombotic thrombocytopenic purpura

The diagnosis of thrombotic thrombocytopenic purpura (TTP) rests on evidence of microangiopathic hemolytic anemia and thrombocytopenia in the absence of disseminated intravascular coagulation and other known causes of thrombotic microangiopathy. Highly specific diagnostic tools such as serum levels of ADAMTS13 are not routinely available for immediate clinical diagnosis. The presence of schistocytes on a blood smear is the morphologic hallmark of the disease, but no guidelines exist as to the number of schistocytes required to differentiate TTP from other thrombotic microangiopathies. We studied 6 patients with TTP and compared their schistocyte counts with those of 40 normal subjects, 28 patients with chronic renal disease, 5 with preeclampsia, and 5 with normal functioning mechanical heart valves. The mean schistocyte count for the TTP patients was 8.35% versus 0.05% for normal subjects, 0.2% for renal patients, 0.25% for preeclamptic patients, and 0.18% for patients with mechanical valves (P < 0.001). Schistocytes were found on 100% of blood films of TTP patients and ranged from 1.0% to 18.4% of red cells. Schistocytes are found on the smears of 58% of normal individuals and on 80-100% of the other patient groups studied, but always comprise less than 0.5% of the red cell population. An initial schistocyte count of greater than 1% strongly suggests a diagnosis of TTP in the absence of other known causes of thrombotic microangiopathy.

Management and monitoring of severe preeclampsia

Preeclampsia is associated with increased maternal and perinatal morbidity and mortality. Preeclampsia is more than pregnancy-induced hypertension. The hypertension is only one manifestation of an underlying multifactorial, multisystem disorder, initiated early in pregnancy. In established severe disease there is volume contraction, reduced cardiac output, enhanced vascular reactivity, increased vascular permeability and platelet consumption. Medical treatment of severe hypertension in pregnancy is required. The more controversial issues are the role of pharmacological treatment in conservative management of severe preeclampsia aiming at prolongation of pregnancy, the ability of such therapy to modify the course of the underlying systemic disorder and the effects on fetal and maternal outcome. This paper presents an overview concerning the current developments in management and monitoring of severe preeclampsia. Controversial topics such as the role of plasma volume expansion in preeclampsia, expectant versus aggressive management of severe preeclampsia remote from term, and pharmacological interventions in the management of eclampsia and the HELLP syndrome are addressed.

Red blood cell survival and kinetics during pregnancy

Profound changes occur during pregnancy in the maternal hematopoietic system in order to meet the needs of the developing fetus and of the mother. By presenting the available data in one review, this review links all known hematopoietic events that occur during normal and certain abnormal pregnancies. Erythropoietin and erythrocyte production are increased during normal pregnancy while erythrocyte mass per unit of body weight remains constant throughout the entire pregnancy, and hemoglobin and hematocrit continuously decrease into the third trimester. Erythrocyte life span is decreased during normal pregnancy due to 'emergency hemopoiesis' in response to elevated erythropoietin levels. In preeclampsia, maternal erythrocytes are of similar to non-pregnant state age distribution, while fetal erythrocytes are of younger age distribution than in normal pregnancy. In gestational diabetes, maternal erythrocyte age distribution is similar to that of normal pregnancy. In multifetal pregnancy, maternal erythrocyte age distribution is younger than that of normal pregnancy.

Effects of red blood cells on the coagulation of blood in normal and preeclamptic pregnancies

OBJECTIVE

The objective of this study was to determine the cellular effects of whole blood, especially of red blood cells, on the hypercoagulability of blood from patients with preeclampsia.

STUDY DESIGN

The time elapsed between mixing and the onset of coagulation was measured by means of a highly sensitive rheometer for whole blood, platelet-rich plasma (in which red blood cells had been removed from whole blood), and platelet-free plasma from 3 groups of subjects: 25 nonpregnant women, 25 women with normal pregnancies, and 10 patients with preeclampsia.

RESULTS

Time to coagulation for whole blood from patients with preeclampsia was significantly shorter than that for whole blood from women with normal pregnancies. However, there was no significant difference in time to coagulation for platelet-rich plasma between women with preeclampsia and those with normal pregnancies.

CONCLUSION

Hypercoagulability of blood in preeclampsia appears to be strongly related to red blood cell alterations.

The procoagulant activity of red blood cells from patients with severe preeclampsia

OBJECTIVE

Our purpose was to determine whether red blood cells from patients with severe preeclampsia may exhibit increased membrane exposure of procoagulant phospholipids (i.e., phosphatidylserine), which may initiate intravascular clotting and platelet activation.

STUDY DESIGN

The study group comprised 28 women: 9 with severe preeclampsia in the third trimester of pregnancy, 10 normotensive with uncomplicated pregnancies, and 9 age-matched, nonpregnant, healthy women. The exposure of phosphatidylserine on the outer membrane phospholipid layer was analyzed with use of isolated, washed red blood cells that were added as a source of phospholipids to a "prothrombinase" coagulation complex.

RESULTS

The resultant thrombin formed was measured by an amidolytic assay. Thrombin generation significantly increased on the addition of red blood cells from women with preeclampsia (741 +/- 132 mU/ml/min) compared with red blood cells from normotensive pregnant (422 +/- 228 mU/ml/min) and nonpregnant women (316 +/- 268 mU/ml/min, p = 0.0008).

CONCLUSION

This study indicates that in patients with preeclampsia the red blood cells exhibit a significant procoagulant surface that may trigger thrombin formation, thereby playing a role in the hypercoagulable state.

Increased ascorbate radical formation and ascorbate depletion in plasma from women with preeclampsia: implications for oxidative stress

There is evidence that oxidative stress accompanies preeclampsia and plasma ascorbate concentrations are reported to be decreased in the disorder. We tested the hypothesis that an ascorbate-oxidizing activity is increased in plasma from women with preeclampsia relative to normal pregnancy. Electron paramagnetic resonance (EPR) spectroscopy was used to determine (1) plasma functional reserves of ascorbate and total thiols, (2) temporal changes in ascorbate and thiol concentrations during incubation of whole blood in vitro, and (3) ascorbate radical signal kinetics in plasma after equalization of ascorbate concentrations. High-pressure liquid chromatography (HPLC) was used to measure plasma alpha-tocopherol. Ascorbate concentrations were 50% lower in preeclampsia relative to normal pregnancy plasma but thiols and alpha-tocopherol did not differ. The elapsed time prior to half-consumption of plasma ascorbate was decreased approximately three-fold during incubation of whole blood from preeclamptics. No concomitant decrease in thiols was evident. The initial ascorbate radical signal amplitude was greater in preeclampsia plasma and then, in contrast to normal pregnancy plasma, decreased progressively. The iron chelator, deferoxamine had no effect on plasma ascorbate radical formation. We conclude that an ascorbate-oxidizing activity is increased in preeclampsia plasma which might contribute to vascular dysfunction in the disorder.

Fatty acid pattern of esterified and free fatty acids in sera of women with normal and pre-eclamptic pregnancy

OBJECTIVE

To determine the composition of esterified and free fatty acids in sera of women with normal and pre-eclamptic pregnancy.

SETTING

Department of Obstetrics and Gynaecology, Aker Hospital, Oslo, Norway.

SUBJECTS

Blood samples were taken from 510 healthy nulliparae at a gestational age of 17-19 weeks. Nineteen of these subsequently developed pre-eclampsia. Seventeen of these, for whom blood samples were still available, and a control group of 17 women taken from the same population and matched for age, body mass index, gestational age and parity, were later studied in detail. A further group of 29 women admitted to the hospital with pre-eclampsia were also studied, as was a matched control group of 29 women with normal pregnancies recruited from the antenatal clinic.

METHODS

Blood samples were drawn after 8 to 10 h fasting. The patterns of serum free fatty acids and esterified fatty acids were determined by thin-layer chromatography combined with gas-liquid chromatography. Free fatty acids were also determined enzymatically.

RESULTS

Among the circulating free fatty acids, the levels of palmitic (16:0), oleic (18:1 n-9) and linoleic acids (18:2 n-6) were significantly higher early in pregnancy in women who later developed pre-eclampsia. The same free fatty acids were also significantly increased in women with pre-eclampsia. The level and composition of the esterified fatty acids in phospholipids, triglycerides and cholesteryl esters did not, however, differ between the two groups early in pregnancy. In contrast, in women with pre-eclampsia, the relative content of oleic acid was increased in the phospholipid fraction, whereas linoleic acid was decreased in the phospholipid and triglyceride fractions.

CONCLUSIONS

We observed that the level and composition of circulating free fatty acids were already altered 10-20 weeks before the clinical onset of pre-eclampsia. When the disease became overt there were changes in both esterified and free fatty acids.

The laboratory evaluation of hypertensive gravidas

A number of laboratory tests are available for the evaluation of the hypertensive gravida. These tests can be used to either predict and/or prognosticate between preeclampsia and other hypertensive disorders of pregnancy. These laboratory tests were evaluated based on published experience with special attention to its ability to facilitate identification of the patient with preeclampsia apart from other hypertensive disorders that co-exist with and occur as a complication of pregnancy. Hypocalciuria and increased cellular plasma fibronectin seem to be good tests to differentiate preeclampsia from chronic hypertension. The management of preeclampsia with its increased risk of perinatal morbidity and mortality renders this differentiation clinically very important. Hyperuricemia, proteinuria, increased serum beta-thromboglobulin concentration, abnormal red blood cell morphology with increased hemoglobin/hematocrit, and increased serum iron individually and collectively reflect the severity of preeclampsia. Platelets and total serum lactate dehydrogenase are the best tests to reflect the severity of HELLP syndrome. Circulating hCG and serum thromboglobulin seem to be the most promising future predictors for preeclampsia.

The Na+/K+ co-transport system in erythrocytes from pregnant patients

In erythrocytes, the extrusion of a cellular sodium level load is accomplished by the Ouabain--sensitive Na+/K+ pump and by the furosemide-sensitive Na+/K(+)--cotransport, which operates against the passive sodium permeability. An abnormal low rate of net sodium extrusion by the Na+/K+ cotransport was observed in pre-eclamptic patients. At the molecular level the cotransport abnormality seems to be the consequence of an apparent diminished affinity for intracellular Na+. Normal pregnancy is characterized by a strong increase of Na+/K+ cotransport efflux. No difference could be detected between the passive sodium permeability of erythrocytes from normotensive pregnant patients and from normotensive non-pregnant controls. Pre-eclampsia seems to be associated with a low passive sodium and potassium permeability. The abnormalities of cotransport and red cell deformability in patients with pre-eclampsia might be interpreted as an early sign of impaired microcirculation and increased vascular reactivity.

A prospective study of several potential biologic markers for early prediction of the development of preeclampsia

OBJECTIVE

The purpose of this study was to prospectively evaluate the predictive performance of several potential biologic markers of preeclampsia used alone or in combination.

STUDY DESIGN

A prospective cohort of 1366 nulliparous women was followed up longitudinally on three occasions during pregnancy. The predictive performance of the tests, used either alone or in combination (stepwise multiple logistic regression), was assessed and compared with that of the mean arterial pressure.

RESULTS

Preeclampsia occurred in 109 of the pregnant women. At a specificity of 80% the sensitivity and the positive and negative predictive values for mean arterial pressure (at a threshold of 87 mm Hg) were 46.6%, 23.5%, and 92.0%, respectively, and the corresponding values for a multiple logistic model at 15 to 24 weeks that included some biologic markers, as well as the mean arterial pressure, were 57.1%, 26.9%, and 93.7%, respectively.

CONCLUSION

Preeclampsia can be predicted by a combination of simple biologic tests with a performance similar to second-trimester mean arterial pressure. However, this procedure is insufficient in terms of clinical usefulness.

Mechanisms of hemolysis and anemia associated with acute antepartum pyelonephritis

Anemia develops in about a fourth of women whose pregnancy is complicated by pyelonephritis, although its exact mechanism has not been defined clearly. In this study of 18 women with antepartum pyelonephritis, although only a third had anemia (hematocrit less than 30 vol/dl), there was evidence for hemolysis in all 18. Specifically there was a mean decrease in hematocrit of 5 vol/dl from admission to discharge. With scanning electron microscopy, we compared erythrocyte morphologic aberrations that were found in women with renal infection with those of normally pregnant women, and the former had significantly increased proportions of echinocytes in particular, but schistocytes and spherocytes were increased also (total 10.3% vs 1.4%, p less than 0.0001). These changes, especially echinocytosis, have been induced in vitro by lipopolysaccharide, and they are known to lead to premature red blood cell destruction in vivo. We conclude that hemolysis with subsequent anemia in pregnant women with pyelonephritis is caused by lipopolysaccharide-induced red blood cell membrane damage.

The HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets): much ado about nothing?

The question of whether the HELLP syndrome exists as a distinct entity or is part of a spectrum of pregnancy complications, which have in common hemolysis, elevated liver enzymes, and thrombocytopenia, has long been a source of speculation and debate among obstetricians and internists. A review of the literature indicates a definite need for a uniform definition, diagnosis, and management of this syndrome. Patients manifesting this syndrome usually are seen before term (less than 36 weeks' gestation) complaining of malaise (90%), epigastric or right upper-quadrant pain (90%), and nausea or vomiting (50%), and some will have nonspecific viral-syndrome-like symptoms. Hypertension and proteinuria may be absent or slight. Thus some of these patients may have a variety of signs and symptoms, none of which are diagnostic of classic preeclampsia. In consideration of the high maternal and perinatal mortality and morbidity reported with the presence of this syndrome, I recommend that all pregnant women having any of these symptoms should have a complete blood cell count with platelet and liver enzyme determinations irrespective of maternal blood pressure.

Repeated cranial computed tomographic and magnetic resonance imaging scans in two cases of eclampsia

In two cases of eclampsia with consumptive thrombocytopenia, the maximum increase in blood pressure and the lowest platelet count coincided with the maximum degree of neurologic and neuroradiologic abnormality. Computed tomograms showed decreased attenuation, and T2-weighted magnetic resonance images showed increased signal intensity focally in the cerebral cortex and the deep gray and white matter. Blood pressure, platelet count, clinical status, and roentgenograms normalized completely in both cases. Severe arterial hypertension and disseminated transitory microvascular occlusions presumably caused multiple small foci of brain edema that resolved without remaining detectable ischemic brain damage.

Hemodynamic and hemorheological profiles in women with proteinuric hypertension of pregnancy and in pregnant controls

We obtained blood samples from 52 patients with pre-eclampsia and from 40 pregnant controls for measurement of plasma urate levels, hematocrit, white cell count and various hemorheological parameters. We also used impedance cardiography to measure cardiac output in both groups and from the results derived values for total peripheral resistance and oxygen transport. Central venous pressure was measured with a superior vena cava catheter in patients with pre-eclampsia but not in controls. Women with pre-eclampsia had significantly lower cardiac output and central venous pressure when compared with a control group. A modest correlation was observed between central venous pressure and cardiac output. The majority of pre-eclamptic patients had significantly raised hematocrit, leucocyte count, uric acid and red cell aggregation. Red cell deformability was significantly decreased in patients with pre-eclampsia. Most patients with severe pre-eclampsia (BP diast. greater than 100 mmHg) had a low Antithrombin III and colloid osmotic pressure level. The leucocyte count was raised when compared with the women with moderate pre-eclampsia. Oxygen delivery was reduced in patients with pre-eclampsia because of impaired rheological properties of their blood.

Erythrocyte morphologic features and serum chemistry studies in ovine pregnancy-induced hypertension treated with thromboxane synthetase inhibitors

Erythrocyte morphologic characteristics and serum chemistry results were studied in 10 gravid ewes during experimental ovine pregnancy-induced hypertension and subsequent administration of the thromboxane synthetase inhibitors CGS13080 and CGS12970. During the hypertensive period mean arterial blood pressure, plasma thromboxane B2 levels, and serum chemistry results, and electrolyte levels were significantly altered. Parameters returned to baseline values or were improved after drug administration. Erythrocyte morphologic features did not change significantly with the onset of the syndrome. Echinocytosis was present during baseline measurement and persisted throughout hypertension. However, after thromboxane synthetase inhibition, percentages of discocytes increased (p less than or equal to 0.005) with the same frequency that echinocyte numbers decreased (p less than or equal to 0.05). Schistocytes were present throughout the study, and changes in their numbers were not detected. Serum phosphorus, blood urea nitrogen, and bilirubin levels and anion gap rose significantly during hypertension and returned to normal levels after drug treatment. We speculate that CGS13080 or CGS12970, by decreasing thromboxane levels and blood pressure, promoted the normalization of erythrocyte membranes.

HELLP syndrome: a severe consequence of pregnancy-induced hypertension

A severe consequence of pregnancy-induced hypertension can be the development of HELLP syndrome (H = hemolysis; EL = elevated liver enzymes; LP = low platelets). The etiology and clinical manifestations of HELLP syndrome are discussed through a review of research findings and a case study. Nursing interventions to facilitate recognition and management of pregnant women with this life-threatening condition are presented.

Blood rheology and pregnancy

Pregnancy is a hypervolaemic situation with early expanded plasma volume, a high cardiac output and a decrease in the vascular and rheological resistance. The increase in plasma volume correlates better with fetal size than maternal size. The hypervolaemic and vasodilated state that accompanies normal pregnancy results in a high flow in the uterine arteries. In contrast, patients with PIH (pregnancy-induced hypertension) or placental insufficiency may have a contracted plasma volume secondary to diffuse vasoconstriction. In spite of the intense vasospasm and hypovolaemia, pre-eclampsia has generally a cardiac output which may be equal, higher or lower compared with non-eclamptic pregnancy. Hypovolaemia is reflected in a higher haematocrit than normal. In the case of a hypovolaemic state, haemoconcentration is associated with high red cell aggregation. In fetal distress and severe PIH, the rheological status (haemoconcentration and elevated red cell aggregation) has a high predictive value for perinatal complications. In patients with severe PIH, erythrocyte filtration is impaired. The increased leukocyte count in patients with PIH may occlude small vessels and could be a factor impairing intervillous blood flow. The increased erythrocyte rigidity may result from a re-distribution of cellular calcium metabolism (Blaustein concept). We conclude that there is an optimal haematocrit during pregnancy between 30% and 38%. The presence of a high haematocrit and in addition elevated red cell aggregation should alert the physician to an increased risk of fetal compromise.

Pulmonary injury complicating antepartum pyelonephritis

Over a 7-year period, 15 pregnant women admitted to Parkland Memorial Hospital for acute pyelonephritis developed respiratory insufficiency characterized by dyspnea, tachypnea, hypoxemia, and radiographic evidence of pulmonary infiltrates. Clinical manifestations usually appeared 24 to 48 hours after the patient was admitted and varied from mild respiratory distress to pulmonary failure in three; these three required tracheal intubation and mechanical ventilation. We found no evidence that pulmonary edema was caused by intravenous fluid overload. Oxygen therapy and ventilation were given to maintain the arterial PO2 at 80 mm Hg or greater, and erythrocyte transfusions were given to six women to correct anemia. Women with pulmonary injury were more likely to have multisystem derangement than a control group without respiratory involvement, but there were no clinical risk factors that were predictive at admission. This syndrome was probably caused by permeability pulmonary edema, likely mediated by endotoxin-induced alveolar-capillary membrane injury since other evidence of endotoxemia was common. Thrombocytopenia, hemolysis, intravascular coagulation, renal dysfunction, and transient cardiomegaly concomitant with hyperdynamic ventricular function are all explicable from endotoxin effects.