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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The umbilical venous oxygen and carbon dioxide tensions, pH, lactate and glucose concentrations, nucleated red cell (erythroblast) count, and haemoglobin concentration were measured in 38 cases of intrauterine growth retardation in which fetal blood sampling was performed by cordocentesis. The oxygen tension was below the normal mean for gestational age in 33 cases; in 14 it was below the lower limit of the 95% confidence interval for normal pregnancies. The severity of fetal hypoxia correlated significantly with fetal hypercapnia, acidosis, hyperlacticaemia, hypoglycaemia, and erythroblastosis. These findings indicate that "birth asphyxia" is not necessarily due to the process of birth.
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PMID:Prenatal asphyxia, hyperlacticaemia, hypoglycaemia, and erythroblastosis in growth retarded fetuses. 310 90

Modern ultrasound techniques enable dynamic studies of fetal activity in utero to be studied and quantified. Real-time B-mode scanning has become the method of choice for this purpose because of its ease of use and precision. Fetal movements can be visualized as early as in the seventh week of pregnancy and the development of the movement patterns can be followed throughout the pregnancy. Up to 16 types of movements have been described by several research groups. In early pregnancy, the finding of normal fetal movements is a good prognostic sign in cases of threatened abortion. A decrease in the movement incidence or a qualitative change of the movements are associated with poor outcome. In late pregnancy, the mean incidence of general fetal movements has been found on average to be 9 to 18 per cent of observation time. Fetal breathing movements, mainly with typical "see-saw' configurative changes of the fetal trunk, occur episodically: both long-term and short-term periodicity have been revealed. For recognition of the time incidence pattern of fetal movements or breathing, a sufficiently long observation time (80 to 100 minutes) is necessary. The incidence of fetal breathing movements increases with gestational age and breathing movements become more regular in mature fetuses. Fetal motor activity is subject to several external influences: glucose given to the mother causes an increase in the fetal breathing movement incidence; maternal hypercarbia stimulates the fetal breathing movements; alcohol administered to the mother abolishes fetal breathing; maternal smoking changes the time spacing of breathing and increases the fetal breathing rate; and exposure of the fetus to sound causes an increase in the number of movements. Real-time ultrasonography enables detection and recording of several other fetal activities: hiccups, swallowing and changes in the stomach volume, micturition, and fetal eye movements. The latter fetal activity is used together with fetal movements, fetal mouth movements and fetal heart rate for the identification of the fetal behavioural states. Quantification of fetal activity as a clinical test of fetal well-being was expected to give an alarm signal in cases of fetal hypoxia and imminent asphyxia. In general, the predictive value of a negative result (i.e., a finding of normal fetal activity) was high; the predictive value of decreased or abnormal fetal activity was found to be much less predictive of fetal compromise.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Ultrasonic assessment of fetal activity. 636 Apr 64

The effect of hypoxia upon the fetus is dependent upon not only the degree of hypoxia induced but probably also upon gestational age and the initial level of fetal oxygenation. Mild hypoxia (12% or over) causes fetal tachycardia, while a more severe insult may cause bradycardia. The effect of hypoxia upon FBM in human pregnancy is uncertain, but depending upon the severity of the hypoxia, it is likely that FBM is reduced or abolished. Hyperoxia has little effect upon the fetal heart rate or FBM in normal circumstances, but an increase in FBM occurs in the presence of fetal hypoxia. No significant change in fetal heart rate in human pregnancy occurs during hypercapnia which is, however, a potent stimulus to fetal breathing. On the other hand, hypocapnia caused by hyperventilation is associated with a decrease in FBM with no obvious change in fetal heart rate. Smoking is associated with a fetal tachycardia and a decrease in FBM. The decrease in FBM is small, the effect being maximal at 30 min after smoking with recovery by 90 min.
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PMID:The fetal response to changes in the composition of maternal inspired air in human pregnancy. 677 32

Laser Doppler flowmetry (LDF) has been used to measure flow in various organs of the adult, but has not been applied to the mammalian fetus. The purpose of this study was to apply LDF to measure cerebral blood flow of the fetal sheep and to assess the possible errors and artifacts of the method caused by myometrial, fetal, and maternal movements. By three days after probe placement, the flow signal had decreased 55% from initial post surgical readings and thereafter it became stable. During fetal hypoxia, the signal increased 48% and during hypercarbia it increased 59%. After fetal death, the signal decreased to 48% of control level. After maternal death, it decreased to 9% and electrical zero could not be reached. LDF is useful to measure changes of fetal cerebral microvascular perfusion because it can provide continuous signals but care is required in data handling and probe fixation when used for the mammalian fetus.
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PMID:Application of laser Doppler flowmetry to measure cerebral microvascular perfusion in the fetal sheep. 1075 Mar 39

The pathophysiology of asphyxia generally results from interruption of placental blood flow with resultant fetal hypoxia, hypercarbia, and acidosis. Circulatory and noncirculatory adaptive mechanisms exist that allow the fetus to cope with asphyxia and preserve vital organ function. With severe and/or prolonged insults, these compensatory mechanisms fail, resulting in hypoxic ischemic injury, leading to cell death via necrosis and apoptosis. Permanent brain injury is the most severe long-term consequence of perinatal asphyxia. The severity and location of injury is influenced by the mechanisms of injury, including degree and duration, as well as the developmental maturity of the brain.
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PMID:Pathophysiology of Birth Asphyxia. 2752 44