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Dallmann A, Ince I, Meyer M, Willmann S, Eissing T, Hempel G. Gestation-Specific Changes in the Anatomy and Physiology of Healthy Pregnant Women: An Extended Repository of Model Parameters for Physiologically Based Pharmacokinetic Modeling in Pregnancy. Clin Pharmacokinet 2018; 56:1303-1330. [PMID: 28401479 DOI: 10.1007/s40262-017-0539-z] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND In the past years, several repositories for anatomical and physiological parameters required for physiologically based pharmacokinetic modeling in pregnant women have been published. While providing a good basis, some important aspects can be further detailed. For example, they did not account for the variability associated with parameters or were lacking key parameters necessary for developing more detailed mechanistic pregnancy physiologically based pharmacokinetic models, such as the composition of pregnancy-specific tissues. OBJECTIVES The aim of this meta-analysis was to provide an updated and extended database of anatomical and physiological parameters in healthy pregnant women that also accounts for changes in the variability of a parameter throughout gestation and for the composition of pregnancy-specific tissues. METHODS A systematic literature search was carried out to collect study data on pregnancy-related changes of anatomical and physiological parameters. For each parameter, a set of mathematical functions was fitted to the data and to the standard deviation observed among the data. The best performing functions were selected based on numerical and visual diagnostics as well as based on physiological plausibility. RESULTS The literature search yielded 473 studies, 302 of which met the criteria to be further analyzed and compiled in a database. In total, the database encompassed 7729 data. Although the availability of quantitative data for some parameters remained limited, mathematical functions could be generated for many important parameters. Gaps were filled based on qualitative knowledge and based on physiologically plausible assumptions. CONCLUSION The presented results facilitate the integration of pregnancy-dependent changes in anatomy and physiology into mechanistic population physiologically based pharmacokinetic models. Such models can ultimately provide a valuable tool to investigate the pharmacokinetics during pregnancy in silico and support informed decision making regarding optimal dosing regimens in this vulnerable special population.
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Affiliation(s)
- André Dallmann
- Department of Pharmaceutical and Medical Chemistry, Clinical Pharmacy, Westfälische Wilhelm-University Münster, Münster, Germany
| | - Ibrahim Ince
- ET-TD-ET Systems Pharmacology CV, Bayer AG, Leverkusen, Germany.
| | - Michaela Meyer
- DD-CS Clinical Pharmacometrics, Bayer AG, Wuppertal, Germany
| | - Stefan Willmann
- DD-CS Clinical Pharmacometrics, Bayer AG, Wuppertal, Germany
| | - Thomas Eissing
- ET-TD-ET Systems Pharmacology CV, Bayer AG, Leverkusen, Germany
| | - Georg Hempel
- Department of Pharmaceutical and Medical Chemistry, Clinical Pharmacy, Westfälische Wilhelm-University Münster, Münster, Germany
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Sharp MK, Gregg M, Brock G, Nair N, Sahetya S, Austin EH, Mascio C, Slaughter MD, Pantalos GM. Comparison of Blood Viscoelasticity in Pediatric and Adult Cardiac Patients. Cardiovasc Eng Technol 2017; 8:182-192. [PMID: 28283942 DOI: 10.1007/s13239-017-0300-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/27/2017] [Indexed: 11/30/2022]
Abstract
Evidence is accumulating that blood flow patterns in the cardiovascular system and in cardiovascular devices do, in some instances, depend on blood viscoelasticity. Thus, to better understand the challenges to providing circulatory support and surgical therapies for pediatric and adult patients, viscous and elastic components of complex blood viscoelasticity of 31 pediatric patients were compared to those of 29 adult patients with a Vilastic-3 rheometer. A random effects model with categorical age covariates found statistically significant differences between pediatric and adult patients for log viscosity (p = 0.005). Log strain (p < 0.0001) and hematocrit (p < 0.0001) effects were also significant, as were the hematocrit-by-log-strain (p = 0.0006) and age-by-log strain (p = 0.001) interactions. The hematocrit-by-age interaction was not significant. For log elasticity, age differences were insignificant (p = 0.39). The model for log elasticity had significant log strain (p < 0.0001), log strain squared (p < 0.0001) and hematocrit (p < 0.0001) effects, as well as hematocrit-by-log-strain and hematocrit-by-log-strain-squared interactions (p = 0.014). A model for log viscosity with continuous age was also fit to the data, which can be used to refine cardiovascular device design and operation to the age of the patient. We conclude that there are distinct differences between pediatric and adult blood viscosity, as well as substantial variation within the pediatric population, that may impact the performance of devices and procedures.
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Affiliation(s)
- M Keith Sharp
- Department of Mechanical Engineering, University of Louisville, 200 Sackett Hall, Louisville, KY, 40292, USA.
| | - Mary Gregg
- School of Public Health, University of Louisville, Louisville, KY, USA
| | - Guy Brock
- School of Public Health, University of Louisville, Louisville, KY, USA
| | - Neema Nair
- Department of Mechanical Engineering, University of Louisville, 200 Sackett Hall, Louisville, KY, 40292, USA
| | - Sarina Sahetya
- Cardiovascular Innovation Institute, University of Louisville, Louisville, KY, USA
| | - Erle H Austin
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, KY, USA
| | - Christopher Mascio
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, KY, USA
| | - Mark D Slaughter
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, KY, USA
| | - George M Pantalos
- Cardiovascular Innovation Institute, University of Louisville, Louisville, KY, USA.,Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, KY, USA
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Brun JF, Boulot P, Varlet-Marie E. Actual vs optimal fetal hematocrit measured with punctures of cord blood in utero: Relationship with umbilical artery resistance. Clin Hemorheol Microcirc 2016; 64:789-797. [PMID: 27767969 DOI: 10.3233/ch-168016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Physiological studies on fetal blood in narrow glass tubes have suggested that fetal optimal hematocrit (hct) might be as high as 60%. A theoretical 'ideal' hct can also be predicted with a theoretical curve of hematocrit/viscosity (h/η) ratio vs hct constructed with Quemada's model. We used the database of one of our previous papers on fetal hemorheology to reinterpret its results with this concept. A series of 28 intrauterine cord punctures (between 19 and 33 weeks gestation) with doppler measurements of resistance in umbilical arteries was studied. The theoretical 'optimal hematocrit' was well correlated to actual (r = 0.857, p < 0.01) but systematically lower (Bland-Altman plot +12.1[8.52-15.7]) than the actual one. Umbilical artery resistance index is correlated with actual hematocrit (r = 0.407, p < 0.05), the discrepancy between ideal and actual (r = - 0.542, p < 0.05) but not predicted ideal hematocrit, suggesting that the discrepancy between ideal and actual may reflect an adaptative decrease aiming at reducing vascular resistance. These findings indicate that prediction of ideal hematocrit with Quemada's equation makes sense in fetal blood, and suggest that a 'viscoregulatory mechanism' maintains hematocrit below this theoretical value in order to avoid excess vascular resistance.
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Affiliation(s)
- Jean-Frédéric Brun
- UMRCNRS 9214-InsermU1046, «Physiopathologie & Médecine Expérimentale du Cœur et desMuscles - PHYMEDEXP», Unité d'Explorations Métaboliques (CERAMM), Université de Montpellier, Département de Physiologie Clinique, Hópital Lapeyronie CHU Montpellier, France
| | - Pierre Boulot
- Service de Gynécologie Obstétrique, Hópital Arnaud de Villeneuve, CHU Montpellier, France
| | - Emmanuelle Varlet-Marie
- Service de Gynécologie Obstétrique, Hópital Arnaud de Villeneuve, CHU Montpellier, France.,Institut des Biomolécules Max Mousseron (IBMM) UMR CNRS 5247, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, France
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Foley ME, Collins R, Stronge JM, Drury MI, Macdonald D. Blood viscosity in umbilical cord blood from babies of diabetic mothers. J OBSTET GYNAECOL 2009. [DOI: 10.3109/01443618109067427] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Kametas NA, Krampl E, McAuliffe F, Rampling MW, Nicolaides KH. Pregnancy at high altitude: a hyperviscosity state. Acta Obstet Gynecol Scand 2004; 83:627-33. [PMID: 15225186 DOI: 10.1111/j.0001-6349.2004.00434.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Pregnancy at high altitude has been associated with intrauterine growth restriction and preeclampsia. These conditions, at sea level, have been linked to increased hematocrit and blood viscosity. The aim of this study was to investigate the effect of high altitude on maternal hemorheology. METHODS This was a cross-sectional study. We examined 94 pregnant women at 10-38 weeks of gestation resident at high altitude (4370 m above sea level) and 75 at sea level, and 24 and 17 nonpregnant women at each altitude, respectively. Blood and plasma viscosity, hematocrit, plasma fibrinogen, albumin and total protein concentrations were determined in blood samples obtained after an overnight period of fasting. RESULTS Pregnancy at high altitude, compared to sea level, is characterized by higher hematocrit, blood viscosity (at high shear rate), plasma viscosity, total protein and fibrinogen concentrations (25%, 38%, 7%, 13.3% and 25%, respectively) and 6% lower albumin concentration. Nonpregnant women at high altitude, compared to sea level, had higher hematocrits, blood viscosity, plasma viscosity, total protein and fibrinogen concentrations (25%, 55%, 18%, 26% and 98%, respectively) and 13% lower albumin concentration. CONCLUSION Pregnancy at high altitude compared to sea level is characterized by increased blood viscosity as a result of increased hematocrit and plasma viscosity.
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Affiliation(s)
- Nikos A Kametas
- Harris Birthright Research Center for Fetal Medicine, King's College Hospital, London, UK.
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Martínez-Morales S, Bonillo-Perales A, Muñoz-Hoyos A, Puertas-Prieto A, Uberos-Fernández J, Molina-Carballo A, Bonillo-Perales JC, Sabatel-López R. The influence of maternal erythrocyte deformability on fetal growth, gestational age and birthweight. J Perinat Med 1999; 27:166-72. [PMID: 10503176 DOI: 10.1515/jpm.1999.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The increase in blood viscosity during pregnancy reduces maternal-fetal blood flow, which can lead to fetal hypoxia and acidosis. These factors have been related to a reduction in fetal growth and to premature births. We carried out a longitudinal study of 36 normal-term gestations at different stages of the pregnancy. We analyzed the erythocyte deformability, the intraerythocyte viscosity and the plasma viscosity in the mother, as well as the relation of these parameters to fetal growth (biparietral diameter (BPD) and length of the femur), birthweight, gestational age at birth and the Agpar score. The results obtained were as follows: from weeks 25 to 36 of pregnancy (30.9 (SD 2 weeks)) there occurs a significant increase in maternal erythocyte rigidity (p < 0.05) (despite the compensatory decrease in intracellular viscosity). This increase is very significantly related to the fetal biparietral diameter (r = -0.50, p < 0.01), the length of the fetal femur (r = -0.48, p < 0.02), gestational age at birth (r = -0.73, p < 0.0001, birthweight (r = -0.63, p < 0.001) and the Agpar score 5 minutes after birth (r = 0.67, p < 0.001). Our conclusions are that the reduction in erythocyte deformability (which we attribute to alterations in the fluidity or elasticity of its membrane) and the factors that increase the aggregation capacity of the red cells (modulators of blood viscosity and of blood flow in the placental intervillous space) are risk factors for reduced fetal growth, lower birthweight and lower gestational age at birth. By avoiding maternal hematocrit levels higher than 36% we could improve uteroplacental perfusion, fetal growth and perinatal results.
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Affiliation(s)
- S Martínez-Morales
- Department of Obstetrics and Gynecology, Hospital de Poniente, Almería, Spain
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Meilahn EN, Kuller LH, Matthews KA, Kiss JE. Hemostatic factors according to menopausal status and use of hormone replacement therapy. Ann Epidemiol 1992; 2:445-55. [PMID: 1342295 DOI: 10.1016/1047-2797(92)90094-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The rise in cardiovascular disease (CVD) risk after menopause may be reduced by hormone replacement therapy (HRT) although the mechanism is unclear. Because little is known about the potential role of hemostatic factors, fibrinogen level and other coagulation parameters were measured in a study on the change in CVD risk factors through the climacteric (the Healthy Women Study). Of 239 subjects measured to date, 32 taking aspirin or other medications thought to alter coagulation were excluded from analyses. Results (adjusted for age and obesity) showed that women taking HRT had lower plasma concentrations of fibrinogen and higher levels of plasminogen and factor VIIc than did postmenopausal subjects not taking HRT. Pre- as compared with postmenopausal women had lower plasma levels of fibrinogen, factor VIIc, and antithrombin III. Adjusting for cigarette smoking did not change the findings. Thus, among women aged 49 to 55, selected hemostatic measures varied (within normal ranges) by menopausal status and were altered by HRT. These findings generally support a hypothesis of hemostatic change contributing to the increase of CVD after menopause. The fact that subjects taking HRT showed no increase in fibrinogen relative to premenopausal women is consistent with an observed decreased risk of CVD among women taking HRT, while the implication of an elevation in factor VIIc among these women is uncertain.
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Affiliation(s)
- E N Meilahn
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, PA 15261
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Jones JG. Haemorheology in Neonates: Procoagulant Activity in Leukocytes. Med Chir Trans 1991. [DOI: 10.1177/014107689108400422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- J G Jones
- Editorial Representative Forum on Clinical Haemorheology
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Umapathysivam K, Haskard KA, Meffin E, Jones WR. Correlation of umbilical cord whole blood viscosity and the presence of fetal distress at birth: a mathematical modelling study. Aust N Z J Obstet Gynaecol 1990; 30:71-3. [PMID: 2346456 DOI: 10.1111/j.1479-828x.1990.tb03201.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This study was designed to investigate the relationship between umbilical cord blood viscosity and clinical parameters such as maternal parity, maternal smoking, mode of delivery, sex of infant and the incidence of fetal distress at birth using mathematical modelling. The results demonstrated vaginal delivery, male infants, infants of primigravidas and low cord whole blood viscosity at a high shear rate were covariables and were associated with an increased incidence of fetal distress and low Apgar scores.
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Affiliation(s)
- K Umapathysivam
- Department of Obstetrics & Gynaecology, Flinders University of South Australia, Bedford Park
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Hau J, Poulsen O, Brandt A, Alexandersen S. Breeding season and pregnancy-associated increase in plasma levels of fibrin/fibrinogen in the mink. Anim Reprod Sci 1988. [DOI: 10.1016/0378-4320(88)90033-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
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.
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Abstract
The blood in neonates shows several peculiar properties which affect its rheological properties. 1. The haematocrit in neonates may be as high as 0.65 l/l without any clinical signs. 2. Both plasma viscosity and red cell aggregation are markedly lower in neonates than in adults because of low protein levels in neonates. This results in decreased blood viscosity at given haematocrit, particularly at low shear forces. 3. Deformability of neonatal red cells is similar to that of adult cells when studied under controlled conditions (e.g. rheoscope, ektacytometer). However, neonatal red cells are less filterable and require higher pressures for entering narrow micropipettes than adult red cells due to the larger size of neonatal red cells. 4. Neonatal leukocytes require higher pressure for the passage of 5 microns filter pores or 5 microns micropipettes than adult cells. The following haemorheological disorders have been observed in neonates: 1. Polycythaemia in infants with late cord-clamping, severe asphyxia, growth retardation and diabetic mothers. 2. Markedly decreased red cell deformability in septicaemia, necrotizing enterocolitis and in vitamin E deficiency (after exposure to oxidizing agents). 3. Moderately decreased red cell deformability in infants with diabetic mothers, growth retardation and severe acidosis. 4. Increased red cell aggregation in septicaemia. 5. Lack of red cell aggregation in immature neonates. 6. Decreased ability of leukocytes from septic neonates to pass filter pores and micropipettes. Treatment may be either haemodilution (in polycythaemia) or exchange transfusion (in septicaemia and necrotizing enterocolitis). Haemorheological drugs have not been used in neonates.
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Ueda S, Fortune V, Bull BS, Valenzuela GJ, Longo LD. Estrogen effects on plasma volume, arterial blood pressure, interstitial space, plasma proteins, and blood viscosity in sheep. Am J Obstet Gynecol 1986; 155:195-201. [PMID: 3728586 DOI: 10.1016/0002-9378(86)90110-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In adult castrated ewes the infusion of 17 beta-estradiol for 3 weeks was associated with a 12% increase in body weight, a 20% increase in whole blood volume (mainly due to a 27% increase of plasma volume), a 13% decrease in mean arterial blood pressure, and a 40% increase in heart rate. The change in plasma volume correlated with the change in estradiol concentration (r = 0.72). Most of the fluid was retained in the interstitial space, as represented by a 6 kg weight gain, 10% of which was in the intravascular compartment. Whole blood and plasma viscosity increased 16% and 21%, respectively, thus reversing some of the blood volume effects toward a hyperdynamic cardiovascular state. We conclude that many of the cardiovascular and hematologic changes with estrogen administration are similar to the changes observed during pregnancy, with the proposed requirement of decrease in mean arterial blood pressure as a condition for blood volume expansion.
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FitzGerald DE, Stuart B, Drumm JE, Duignan NM. The assessment of the feto-placental circulation with continuous wave Doppler ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 1984; 10:371-376. [PMID: 6464222 DOI: 10.1016/0301-5629(84)90171-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Continuous wave Doppler ultrasound was used together with B-mode real time ultrasound to study feto-placental blood flow in utero. The results of 887 examinations on 221 patients are presented. The fetal heart rate acceleration slope and pulsatility index (P.I.) of the audiofrequency ultrasound display were analysed. There was a significant reduction in fetal heart rate (P less than 0.001) and P.I. (P less than 0.001) with advancing gestational age in normal pregnancy. In contrast, in retarded intrauterine growth a significant increase in P.I. values was observed in 77% of patients.
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Abstract
Adult and newborn infant blood viscosity have been compared, taking into account not only the hematocrit, but also the type of red blood cells (fetal or adult) in the circulation and the plasma viscosity. At all shear rates studied, the viscosity of the adults' blood was higher than that of the newborn infant. At shear rates of 11.5 and 46 second-1, an increase in the hematocrit influences the viscosity of neonatal and adult blood similarly. At 115 and 230 second-1, the rise in hematocrit was associated with a greater increase in viscosity in the presence of fetal red blood cells, probably because of their lesser deformability. Plasma viscosity was 1.18 +/- 0.17 centipoises in the newborn compared to 1.36 +/- 0.10 in the adult group (P less than 0.001). The relative apparent viscosity (apparent viscosity/plasma viscosity) was higher in the neonate at a hematocrit of 65% (P less than 0.05). In normal conditions, blood viscosity is lower in the neonatal period because of a lower plasma viscosity.
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Christiaens GC, Sixma JJ, Haspels AA. Haemostasis in menstrual endometrium in the presence of an intrauterine device. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1981; 88:825-37. [PMID: 7260004 DOI: 10.1111/j.1471-0528.1981.tb01310.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The histology and ultrastructure of the haemostatic response in the endometrium have been studied in 12 uteri containing an inert or copper wound intrauterine contraceptive device (IUCD). The uteri were removed during the premenstrual phase or during the first 96 hours of menstruation. The results have been compared to earlier observations in non-IUCD influenced endometrium. In all uteri the tissue shedding proceeded more slowly in the presence of an IUCD and considerably fewer haemostatic plugs were found. The platelets in these plugs were more loosely packed and less degranulated, and the plugs contained less fibrin than in the absence of an IUCD. Haemostatic plugs were still observed at times when no such plugs were seen in uteri without an IUCD. Unoccluded vessel lesions were regularly seen and vessels open to the shedding surface were occasionally encountered. These observations suggest that IUCD-induced menorrhagia is caused by the combination of delayed shedding and a decreased haemostatic reaction in the endometrium.
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