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Stuart Campbell - One of the best experts on this subject based on the ideXlab platform.
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fetal venous intracardiac and arterial Blood flow measurements in intrauterine growth retardation relationship with fetal Blood Gases
American Journal of Obstetrics and Gynecology, 1995Co-Authors: K Hecher, R J M Snijders, Stuart Campbell, K H NicolaidesAbstract:Abstract OBJECTIVE: Our purpose was to investigate arterial, venous, and intracardiac Blood flow in growth-retarded fetuses and to relate the Doppler results to Blood Gases in umbilical venous Blood obtained by cordocentesis. STUDY DESIGN: A cross-sectional, pulsed-wave color Doppler ultrasonographic study of 23 severely growth-retarded fetuses undergoing cordocentesis and measurement of Blood Gases was performed. Blood velocity waveforms were recorded from the descending thoracic aorta, middle cerebral artery, inferior vena cava, duclus venosus, and atrioventricular valves. RESULTS: The Doppler studies demonstrated evidence of redistribution in the arterial system with increased impedance to flow in the aorta and decreased impedance in the cerebral circulation. The velocity of flow in the venous system and across the atrioventricular valves was decreased, whereas pulsability of waveforms in the inferior vena cava and ductus venosus was increased. The mean umbilical venous Blood Po 2 and pH were decreased, and there were significant associations between Blood Gases and Doppler parameters in the thoracic aorta, middle cerebral artery, and ductus venosus. CONCLUSION: In severe intrauterine growth retardation the degree of fetal acidemia can be estimated from Doppler measurements of pulsatility in both the arterial system and the ductus venosus.
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doppler measurements of fetal and uteroplacental circulations relationship with umbilical venous Blood Gases measured at cordocentesis
American Journal of Obstetrics and Gynecology, 1990Co-Authors: C M Bilardo, K H Nicolaides, Stuart CampbellAbstract:A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood Gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the Blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal Blood Gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory Gases.
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doppler measurements of fetal and uteroplacental circulations relationship with umbilical venous Blood Gases measured at cordocentesis
American Journal of Obstetrics and Gynecology, 1990Co-Authors: C M Bilardo, K H Nicolaides, Stuart CampbellAbstract:A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood Gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the Blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal Blood Gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory Gases. (Ann J OBSTET GYMECOL 1990;162:115-20.)
K H Nicolaides - One of the best experts on this subject based on the ideXlab platform.
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Blood Gases in pregnancy at sea level and at high altitude
British Journal of Obstetrics and Gynaecology, 2001Co-Authors: Fionnuala M Mcauliffe, Nikos A Kametas, Elisabeth Krampl, John Ernsting, K H NicolaidesAbstract:Abstract Objective 1. To measure Blood Gases and minute ventilation in healthy women with normal pregnancies, compare with non-pregnant women both at sea level and at high altitude; 2. to relate the results at altitude with duration of residence there. Design Cross-sectional study. Setting Antenatal clinics at sea level in Lima, Peru and at high altitude 4300m in Cerro de Pasco, Peru. Population A total of 304 normal pregnant women between 7 and 41 weeks of gestation were studied, including 112 who lived at sea level and 192 at high altitude (4300m). For comparison 38 non-pregnant women (19 at sea level and 19 at high altitude) were also studied. Methods Arterialised Blood Gases, haemoglobin, pulse oximetry and minute ventilation were measured once in each woman. Main outcome measures PO2, PCO2, pH, haemoglobin, oxygen saturation, arterial oxygen content and minute ventilation and their relationship to gestation. Results PO2, PCO2, bicarbonate, base excess and oxygen saturation were lower in pregnancies at high altitude compared with sea level; pH, haemoglobin, arterial oxygen content and minute ventilation were higher. At high altitude oxygen saturation and haemoglobin decreased towards term resulting in a fall in arterial oxygen content at the end of pregnancy. Women whose family had lived at high altitude for at least three generations maintained their oxygenation throughout pregnancy better than women whose family had lived there for less than three generations. Conclusions In pregnancy at high altitude maternal adaptation appeared adequate in the first trimester but declined towards term. However, maternal oxygenation was maintained in those whose family had lived longest at high altitude suggesting a beneficial adaptation to a hypoxic environment, occurring over generations.
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fetal venous intracardiac and arterial Blood flow measurements in intrauterine growth retardation relationship with fetal Blood Gases
American Journal of Obstetrics and Gynecology, 1995Co-Authors: K Hecher, R J M Snijders, Stuart Campbell, K H NicolaidesAbstract:Abstract OBJECTIVE: Our purpose was to investigate arterial, venous, and intracardiac Blood flow in growth-retarded fetuses and to relate the Doppler results to Blood Gases in umbilical venous Blood obtained by cordocentesis. STUDY DESIGN: A cross-sectional, pulsed-wave color Doppler ultrasonographic study of 23 severely growth-retarded fetuses undergoing cordocentesis and measurement of Blood Gases was performed. Blood velocity waveforms were recorded from the descending thoracic aorta, middle cerebral artery, inferior vena cava, duclus venosus, and atrioventricular valves. RESULTS: The Doppler studies demonstrated evidence of redistribution in the arterial system with increased impedance to flow in the aorta and decreased impedance in the cerebral circulation. The velocity of flow in the venous system and across the atrioventricular valves was decreased, whereas pulsability of waveforms in the inferior vena cava and ductus venosus was increased. The mean umbilical venous Blood Po 2 and pH were decreased, and there were significant associations between Blood Gases and Doppler parameters in the thoracic aorta, middle cerebral artery, and ductus venosus. CONCLUSION: In severe intrauterine growth retardation the degree of fetal acidemia can be estimated from Doppler measurements of pulsatility in both the arterial system and the ductus venosus.
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relation of fetal Blood Gases and data from computer assisted analysis of fetal heart rate patterns in small for gestation fetuses
British Journal of Obstetrics and Gynaecology, 1991Co-Authors: Lucia S M Ribbert, K H Nicolaides, Rosalinde J M Snijders, Gerard H A VisserAbstract:Fetal heart rate (FHR) monitoring and computer-assisted analysis were performed immediately before cordocentesis in 25 severely small-for-gestational age fetuses. There were significant associations between FHR variation and both umbilical vein Blood Po2 (r = 0.66) and pH (r = 0.69). However, the wide scatter of values around the regression lines prevented accurate prediction of fetal Blood Gases from FHR patterns. Nevertheless, FHR variation <20 ms was always associated with severe fetal hypoxaemia and acidaemia.
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doppler measurements of fetal and uteroplacental circulations relationship with umbilical venous Blood Gases measured at cordocentesis
American Journal of Obstetrics and Gynecology, 1990Co-Authors: C M Bilardo, K H Nicolaides, Stuart CampbellAbstract:A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood Gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the Blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal Blood Gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory Gases.
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doppler measurements of fetal and uteroplacental circulations relationship with umbilical venous Blood Gases measured at cordocentesis
American Journal of Obstetrics and Gynecology, 1990Co-Authors: C M Bilardo, K H Nicolaides, Stuart CampbellAbstract:A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood Gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the Blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal Blood Gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory Gases. (Ann J OBSTET GYMECOL 1990;162:115-20.)
J F Dhainaut - One of the best experts on this subject based on the ideXlab platform.
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should mechanical ventilation be optimized to Blood Gases lung mechanics or thoracic ct scan
American Journal of Respiratory and Critical Care Medicine, 1995Co-Authors: F Brunet, D Jeanbourquin, Mehran Monchi, Jeanpaul Mira, L Fierobe, Apostolos Armaganidis, Bertrand Renaud, Makhlouf Belghith, Semir Nouira, J F DhainautAbstract:This study was aimed at providing data for optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). The effects of ventilation with positive end-expiratory pressure (PEEP) titrated to Blood Gases were studied by thoracic computed tomographic (CT) scans and lung mechanics measurements in eight patients. CT density histograms at end-expiration were used to investigate the effects of PEEP on three differently aerated zones. Static pressure-volume (P-V) curves were used to determine the deflection point above which baro-volotrauma (a combination of barotrauma and volotrauma) may occur. Peak pressures, plateau pressures, and lung volumes measured by Respitrace were compared with the deflection point. CT scan showed that PEEP increased "normally aerated" areas, decreased "nonaerated" areas, and did not change "poorly aerated" zones. No correlations were found between CT scan and either PaO2 or mechanical data. Pressure at the deflection point was lower than the usually...
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should mechanical ventilation be optimized to Blood Gases lung mechanics or thoracic ct scan
American Journal of Respiratory and Critical Care Medicine, 1995Co-Authors: F Brunet, D Jeanbourquin, Mehran Monchi, Jeanpaul Mira, L Fierobe, Apostolos Armaganidis, Bertrand Renaud, Makhlouf Belghith, Semir Nouira, J F DhainautAbstract:This study was aimed at providing data for optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). The effects of ventilation with positive end-expiratory pressure (PEEP) titrated to Blood Gases were studied by thoracic computed tomographic (CT) scans and lung mechanics measurements in eight patients. CT density histograms at end-expiration were used to investigate the effects of PEEP on three differently aerated zones. Static pressure-volume (P-V) curves were used to determine the deflection point above which baro-volotrauma (a combination of barotrauma and volotrauma) may occur. Peak pressures, plateau pressures, and lung volumes measured by Respitrace were compared with the deflection point. CT scan showed that PEEP increased "normally aerated" areas, decreased "nonaerated" areas, and did not change "poorly aerated" zones. No correlations were found between CT scan and either PaO2 or mechanical data. Pressure at the deflection point was lower than the usually recommended 35 to 40 cm H2O for peak pressure in four patients (range, 28 to 32 cm H2O). With regard to plateau pressures, only one patient was ventilated above the deflection point. However, monitoring of volumes showed that these four patients had an end-inspiratory volume above this point. We conclude that mechanical ventilation may be initially adjusted on the basis of Blood gas values and then optimized on the basis of lung mechanics to limit the risk of baro-volotrauma.
C M Bilardo - One of the best experts on this subject based on the ideXlab platform.
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doppler measurements of fetal and uteroplacental circulations relationship with umbilical venous Blood Gases measured at cordocentesis
American Journal of Obstetrics and Gynecology, 1990Co-Authors: C M Bilardo, K H Nicolaides, Stuart CampbellAbstract:A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood Gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the Blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal Blood Gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory Gases.
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doppler measurements of fetal and uteroplacental circulations relationship with umbilical venous Blood Gases measured at cordocentesis
American Journal of Obstetrics and Gynecology, 1990Co-Authors: C M Bilardo, K H Nicolaides, Stuart CampbellAbstract:A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood Gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the Blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal Blood Gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory Gases. (Ann J OBSTET GYMECOL 1990;162:115-20.)
F Brunet - One of the best experts on this subject based on the ideXlab platform.
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should mechanical ventilation be optimized to Blood Gases lung mechanics or thoracic ct scan
American Journal of Respiratory and Critical Care Medicine, 1995Co-Authors: F Brunet, D Jeanbourquin, Mehran Monchi, Jeanpaul Mira, L Fierobe, Apostolos Armaganidis, Bertrand Renaud, Makhlouf Belghith, Semir Nouira, J F DhainautAbstract:This study was aimed at providing data for optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). The effects of ventilation with positive end-expiratory pressure (PEEP) titrated to Blood Gases were studied by thoracic computed tomographic (CT) scans and lung mechanics measurements in eight patients. CT density histograms at end-expiration were used to investigate the effects of PEEP on three differently aerated zones. Static pressure-volume (P-V) curves were used to determine the deflection point above which baro-volotrauma (a combination of barotrauma and volotrauma) may occur. Peak pressures, plateau pressures, and lung volumes measured by Respitrace were compared with the deflection point. CT scan showed that PEEP increased "normally aerated" areas, decreased "nonaerated" areas, and did not change "poorly aerated" zones. No correlations were found between CT scan and either PaO2 or mechanical data. Pressure at the deflection point was lower than the usually...
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should mechanical ventilation be optimized to Blood Gases lung mechanics or thoracic ct scan
American Journal of Respiratory and Critical Care Medicine, 1995Co-Authors: F Brunet, D Jeanbourquin, Mehran Monchi, Jeanpaul Mira, L Fierobe, Apostolos Armaganidis, Bertrand Renaud, Makhlouf Belghith, Semir Nouira, J F DhainautAbstract:This study was aimed at providing data for optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). The effects of ventilation with positive end-expiratory pressure (PEEP) titrated to Blood Gases were studied by thoracic computed tomographic (CT) scans and lung mechanics measurements in eight patients. CT density histograms at end-expiration were used to investigate the effects of PEEP on three differently aerated zones. Static pressure-volume (P-V) curves were used to determine the deflection point above which baro-volotrauma (a combination of barotrauma and volotrauma) may occur. Peak pressures, plateau pressures, and lung volumes measured by Respitrace were compared with the deflection point. CT scan showed that PEEP increased "normally aerated" areas, decreased "nonaerated" areas, and did not change "poorly aerated" zones. No correlations were found between CT scan and either PaO2 or mechanical data. Pressure at the deflection point was lower than the usually recommended 35 to 40 cm H2O for peak pressure in four patients (range, 28 to 32 cm H2O). With regard to plateau pressures, only one patient was ventilated above the deflection point. However, monitoring of volumes showed that these four patients had an end-inspiratory volume above this point. We conclude that mechanical ventilation may be initially adjusted on the basis of Blood gas values and then optimized on the basis of lung mechanics to limit the risk of baro-volotrauma.