Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DECELERATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,765 records · Page 98Linked to original sources
PubMed2004

Comparison of intrapartum fetal heart rate tracings in patients with neonatal seizures vs. no seizures: what are the differences?

OBJECTIVE: To determine which intrapartum fetal heart rate parameters in the presence of severe neonatal acidosis (pH < 7.0) appropriately predicts the development of neonatal seizures in the context of hypoxic ischemic encephalopathy (HIE). METHODS: The intrapartum fetal heart rate tracings of 25 neonates who developed neonatal seizures secondary to HIE were compared with 25 matched neonates with similar pH and gestational age who did not develop seizures. All patients had at least 2 hours of intrapartum fetal heart rate patterns available for review. We compared the fetal heart rate parameters of prolonged deceleration, variable and late decelerations, variability, accelerations, fetal heart rate baseline and duration of the fetal heart rate abnormality. Comparison between the groups was done using chi-square for nominal data and student t-tests for continuous data. RESULTS: Neonates with seizures 2 degrees HIE had a significantly longer duration of abnormal fetal heart rate patterns (72 +/- 12 minutes vs 48 +/- 12 minutes, p < 0.001). DISCUSSION: This study demonstrated that in the setting of neonatal acidosis the development of seizures is related to the period of stress (duration of the abnormal fetal heart rate pattern).

Adult↗
PubMed2005

Visual analysis of antepartum fetal heart rate tracings: inter- and intra-observer agreement and impact of knowledge of neonatal outcome.

OBJECTIVE: To evaluate the inter- and intra-observer agreement of visual analysis of fetal heart rate tracing and to evaluate the bias introduced by knowledge of perinatal outcome in this interpretation. METHODS: One hundred tracings were independently analyzed by four observers. In a second study period, two observers re-analysed the 100 tracings in order to evaluate intra-observer agreement. The other two observers re-analyzed the tracings, which were labelled with fictitious perinatal outcome to evaluate the impact of this information on reliability. Agreement was analyzed by means of the proportion of agreement for qualitative parameters and the inter- and intra-class correlation coefficient for quantitative data. RESULTS: Poor agreement was found for quantitative variability, low variability category and number of decelerations. Moderate agreement was observed for baseline, normal variability category and number of accelerations. Fetal heart rate variability and number of accelerations and decelerations were found to be significantly influenced by clinical information of perinatal outcome. Biased observers showed lower reliability than unbiased ones. CONCLUSION: Visual assessment of fetal heart rate tracings is unreliable due to low rates of agreement between and within observers. Only qualitative classification such as normal baseline and normal variability showed good agreement. Knowledge of clinical information introduces subjectivity to the visual analysis, leading to a negative impact on reliability.

Bias↗
PubMed1975

Some remarks concerning the fetal heart rate total dip areas.

It was ascertained whether the sum total of the dip areas 60 minutes prior to delivery is an evaluating parameter for judging the fetal state. The cardiotokograms of 62 deliveries with a normal newborn state (newborn index 1) and forty with a pathological newborn state (newborn index 2 and 3) were digitally computer [5]. By proper programming numerous decriptive dip parameter can be determined, e.g. the amplitude, duration, area, lag time, recovery time, fluctuation before, within, and after the dip. The sum total of the dip areas was calculated from the CTG 60 minutes before delivery. Only cardiotokograms with at least two decelerations were included. The pathological newborn group has a larger mean sum total of dip areas than the group with a normal index (Fig. 1). This difference, however, is not significant. Mean values were calculated for other descriptive parameters, e. g. dip fluctuations, lag time, dip amplitude etc. These also differ only slightly between the two groups. (Fig 2). Hence they give no satisfactory decription of the fetal state. By including several dip parameters simultaneously [7] an evaluating parameter can be determined for both decelerations. The various descriptive parameter are given different weights and are added up (discrimination analysis). In analogy to the sum total of the dip areas the sum total of the evaluating parameters was calculated. The difference between the two groups with respect to these evaluating parameter sums is significant. (Fig. 3). The sum of total dip areas alone does not appear to be a sufficient FHR parameter for evaluating the fetal state. Evaluation is significantly improved by considering simultaneously several descriptive parameters.

Female↗
PubMed1983

Maternal half-sitting position in the second stage of labor.

The maternal half-sitting and supine position during the second stage of fullterm labor was compared in 100 women who, after identical opening phases in supine position, randomly delivered in half-sitting (50 degrees, n = 50) or supine position (n = 50). The whole duration of the second stage of labor or the time spent in active pushing did not differ between the groups. Vacuum extraction was needed twice (4%) in the group delivering in half-sitting and six times (12%) in the group delivering in supine position. Vaginal tear occurred in one mother in both groups. Early decelerations in fetal cardiotocography were seen 22 times in half-sitting and 14 times in supine group (p less than 0.05). However, late decelerations were seen in only one mother with half-sitting, as compared to five mothers with supine position. Four infants of mothers giving birth in supine position had 1 minute APGAR scores 7 or less, whereas all infants of mothers delivering in half-sitting position had APGAR scores higher than 7. Subjectively the mothers liked more the half-sitting position. We conclude that a women can deliver in half-sitting position without maternal or fetal risks.

Adult↗
PubMed1985

Catecholamines in arterial and venous umbilical blood: placental extraction, correlation with fetal hypoxia, and transcutaneous partial oxygen tension.

In 34 parturient women the levels of free epinephrine (E), norepinephrine (NE), and dopamine (D) were determined by a radioenzymatic method using maternal venous and umbilical arterial and venous blood. The study was conducted to investigate the relationship between fetal catecholamines and hypoxia, fetal heart rate (FHR), and transcutaneous pO2 (tcpO2). The placental catecholamine extraction rates were also calculated. Results The NE concentrations (10,200 pg/ml) and the E concentrations (1,120 pg/ml) in the fetal arterial blood were highly elevated with mean values increased 4-fold over umbilical vein values. Compared with the maternal venous blood, NE values were increased 20-fold, and E values 10-fold. Free D concentrations in fetal arterial blood (130 pg/ml) had risen 2.5-fold over maternal levels. These results suggest that the catecholamines measured in cord blood are of fetal origin and that the placenta has a high capacity for inactivation of free catecholamines. The placental extraction rate is 77 +/- 14% for NE, 76 +/- 16% for E, and 33 +/- 25% for D. The placental extraction rates for E and NE were virtually identical; in agreement with morphological studies they demonstrated absence of sympathetic innervation on the fetal side of the placenta. Highly significant correlations were found between fetal arterial NE concentrations and the 1-minute APGAR score, pH and base deficit in the umbilical artery and alterations of the FHR (deceleration area, baseline FHR). Further analysis of FHR alterations reveals that an increase in deceleration area without tachycardia is not correlated with an increase of fetal arterial NE concentration. A significant rise in NE was only found with additional tachycardia which is often associated with a loss of oscillation amplitude. Fetal arterial E concentrations were found to correlate with the fetal parameters indicating increased adrenal secretion of the hormone during fetal stress. However, correlation coefficients were lower than those obtained for NE. A significant effect of fetal hypoxia on arterial and venous D levels could not be demonstrated. Fetal tcpO2 varies between 0-25 mm Hg during the last two hours before delivery. In most cases tcpO2 was lower than the arterial pO2. Besides epidermal thickness and artifacts, skin perfusion is a major factor influencing the tcpO2 (transcutaneous arterial pO2 difference). Vasoconstriction of the cutaneous vessels induced by increased NE secretion during hypoxia may obviously produce a fall in tcpO2.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Fetal bradycardia in labor.

The prognostic significance of terminal bradycardia is analysed in this study. Amongst 12,145 intrapartal directly recorded cardiotocograms, 135 heart rate curves free of deceleration (1.1%) were found with an abruptly occurring fetal bradycardia. The mean duration of bradycardia was 5.7 +/- 3.1 minutes, the mean heart rate during the phase of bradycardia was 86.2 +/- 9.9 beats/minute. A premature amniotomy (40%) was significantly correlated with the bradycardia. The mean pH in the umbilical arterial blood was 7.261 +/- 0.072. pH values of less than 7.200 were measured in 21.7% and pH values under 7.150 were measured in 4.2%; a severe acidosis (pH less than 7.100) was not present in any case. The fall in fetal pH in the umbilical arterial blood per minute of bradycardia averages -0.006 units. In the bradycardia group, only 5.2% of all babies were slightly depressed and only 0.7% were severely depressed; 5.9% of the babies had slight difficulties in postpartal adaptation. It is concluded from the data that as a rule the impending spontaneous delivery (head rotated correctly, effective bearing-down efforts) can be waited for in the occurrence of terminal bradycardia (without prior decelerations). The fall in heart rate should not automatically occasion the institution of hazardous delivery maneuvers which may entail a greater danger to the mother and baby than the fetal bradycardia itself.

Adult↗
PubMed1989

Non-invasive continuous fetal transcutaneous pO2 and pCO2 monitoring during labor.

Continuous measurements of fetal scalp transcutaneous pO2 (tcpO2) and pCO2 (tcpCO2) monitoring were performed for 49 patients for the purpose of the evaluation of the fetal well-being. The equipment used was transcutaneous pO2/pCO2 monitor Micro Gas 7640 (KONTRON, Switzerland), which was inserted through the vagina and attached to the fetal head with a suction ring. Blood was taken from the umbilical vessels and pO2 and pCO2 values were analyzed. The correlation coefficient between pO2 in the umbilical artery and tcpO2 was 0.78 (p less than 0.01), and that between pCO2 in the umbilical artery and tcPCO2 was 0.79 (p less than 0.01). Relationships between the transcutaneous blood gas analysis and FHR patterns were discussed. Increase of pCO2 and decrease of tcpO2 was observed in the cases of variable deceleration, not observed in the case of early deceleration. FHR patterns don't always indicate fetal condition, for example in the case of fetal arrhythmia, especially fetal bradycardia. But tcpO2 monitoring of the fetus affected fetal arrhythmia during labor aids diagnosis of fetal distress by FHR patterns, especially in the case of fetuses affected by fetal bradycardia.

Blood Gas Monitoring, Transcutaneous↗
PubMed1990

Fetal heart rate responses to anemia in Rh isoimmunization.

On 52 occasions 24 Rh immunized women were monitored with a nonstress test (NST) prior to fetal blood sampling. Cardiotocographic characteristics were recorded for each NST. Fetal blood was analysed for hemoglobin and hematocrit. Fetal hemoglobin and hematocrit were positively correlated to long-term variability, acceleration amplitude and negatively correlated to deceleration amplitude (linear regression analysis; p less than 0.05). Decelerations were almost without exception associated with low concentrations of hemoglobin and hematocrit. In fetuses of 32 weeks' gestation or more, a loss of variability (less than or equal to 5 bpm) was associated with severe anemia. Hemoglobin and hematocrit were significantly lower in the group with a pathological NST (n = 15) compared with the group with a normal NST (n = 37) (Mann-Whitney U test; p less than 0.05). The predictive value of a pathological test was 13/15 concerning hemoglobin and hematocrit; whereas, the predictive value of a normal test was poor. A pathological NST, especially when decelerative, is a good predictor of fetal anemia, but a normal NST is no guarantee for a normal blood status.

Anemia↗
PubMed1990

Significance of meconium staining of the amniotic fluid.

The study was conducted to determine the significance of meconium staining and more specifically its association with fetal heart rate patterns. Five hundred and one patients in labor were examined, 106 of whom had meconium stained amniotic fluid. A multivariate analysis of the data was performed by logistic regression analysis using meconium staining as the dependent variable. The determinants of meconium in the amniotic fluid were gestational age, base deficit, calcified placenta, late decelerations and placental weight. The following variables had no effect on the occurrence of meconium: maternal age, type of risk, parity, fetal sex, duration of labor, duration of the second stage of labor, entanglement of the umbilical cord, FHR variability, variable decelerations, oxytocin usage, type of anesthesia, maternal smoking and alcohol consumption habits. In conclusion, meconium in the amniotic fluid seems to be associated with placental rather than with umbilical insufficiency.

Amniotic Fluid↗
PubMed1993

Clinical significance of fetal heart rate patterns during labor. IX: Prolonged pregnancy.

The intrapartum FHR and UC were recorded in a population of 707 consecutive cases of prolonged gestation looking for a characteristic pattern. There is no typical pattern for prolonged pregnancy. However, there are differences from preterm and term populations. There is a very high incidence of variable (55%) and late (17%) decelerations. These were seen more frequently among cases receiving oxytocin. Nearly 50% of C-sections had lates. Baseline alterations (tachycardia 26%, fixed 8%, and saltatory 17%) were often associated. Apgar scores < or = 6 at 1 minute were correlated with variable and late decelerations. However, acidemia (UA pH < or = 7.20) could not be predicted from FHR patterns because there was no correlation between low pH and clinical depression. Alarmingly a few fetuses in agonal state presented normal appearing tracings, or deteriorated rapidly without the usual indicative changes by FHR. All intrapartum or NND had this misleading pattern. In view of this unpredictable aberrant pattern as the only certain means to prevent these deaths, it is suggested that no pregnancy should be allowed to reach 294 days post LMP.

Apgar Score↗
PubMed2002

Collision warning timing, driver distraction, and driver response to imminent rear-end collisions in a high-fidelity driving simulator.

Rear-end collisions account for almost 30% of automotive crashes. Rear-end collision avoidance systems (RECASs) may offer a promising approach to help drivers avoid these crashes. Two experiments performed using a high-fidelity motion-based driving simulator examined driver responses to evaluate the efficacy of a RECAS. The first experiment showed that early warnings helped distracted drivers react more quickly--and thereby avoid more collisions--than did late warnings or no warnings. Compared with the no-warning condition, an early RECAS warning reduced the number of collisions by 80.7%. Assuming collision severity is proportional to kinetic energy, the early warning reduced collision severity by 96.5%. In contrast, the late warning reduced collisions by 50.0% and the corresponding severity by 87.5%. The second experiment showed that RECAS benefits even undistracted drivers. Analysis of the braking process showed that warnings provide a potential safety benefit by reducing the time required for drivers to release the accelerator. Warnings do not, however, speed application of the brake, increase maximum deceleration, or affect mean deceleration. These results provide the basis for a computational model of driver performance that was used to extrapolate the findings and identify the most promising parameter settings. Potential applications of these results include methods for evaluating collision warning systems, algorithm design guidance, and driver performance model input.

Accidents, Traffic↗
PubMed1997

Human factors field evaluation of automotive headway maintenance/collision warning devices.

Three on-road studies were conducted to determine how headway maintenance and collision warning displays influence driver behavior. Visual perspective, visual perspective with a pointer, visual perspective combined with an auditory warning, discrete visual warning, and discrete auditory warning were assessed during both coupled headway and deceleration events. Results indicate that when drivers are provided with salient visual information regarding safe headways, they utilize the information and increase their headway when appropriate. Auditory warnings were less effective than visual warnings for increasing headways but may be helpful for improving reaction time during events that require deceleration. Drivers were somewhat insensitive to false alarm rates, at least during short-term use. Finally, and most important, driver headway maintenance increased by as much as 0.5 s when the appropriate visual display was used. However, a study to investigate the longterm effects of such displays on behavior is strongly recommended prior to mass marketing of headway maintenance/collision warning devices.

Accidents, Traffic↗
PubMed1992

Cardiac responsivity in individuals at high risk for alcoholism.

Heart rate was recorded from male siblings over the age of 30 who were members or either alcoholic or control families. Brothers from alcoholic families included both those with a diagnosis of alcoholism (n = 66) and those without such a diagnosis (n = 18). Control brothers (n = 33) were chosen for absences of any Axis I psychopathology including alcoholism in all first- and second-degree relatives. Subjects were engaged in two auditory tasks. All subjects were presented with high- and low-pitched tones with varying probabilities. In the first task (counting), subjects were told to count only the number of high tones. In the second task (choice reaction), subjects were asked to perform a simple motor response to each high or low tone. Prestimulus levels, anticipatory deceleration and acceleration were compared between the three groups. All members of the affected families, whether alcoholic themselves or not, were found to have a significantly higher baseline heart rate than members of control families. In addition, differences in the anticipatory deceleration were greater in control brothers than in brothers from the affected families for the counting task.

Adult↗
PubMed1974

Effects of phentolamine on the SA node of the dog heart in situ.

Direct perfusion of the sinus node artery at constant pressure of 100 mmHg was arranged in 6 canine hearts in situ. The injection of phentolamine into the sinus node artery usually induced dose-dependent positive chronotropic effect. However, at a larger dose of 300 mug, phentolamine frequently induced a biphasic chronotropic response, i.e., sinus deceleration followed by sinus acceleration. Phentolamine at a large dose of 1 mg usually induced a negative chronotropic effect. The threshold dose for inducing sinus acceleration was about 1 to 10 mug. The positive chronotropic response to phentolamine was blocked either by propranolol or by tetrodoxin. That to norepinephrine was blocked by propranolol but not suppressed by tetrodotoxin. These results suggest that the phentolamine-induced sinus acceleration is due to catecholamine which is released by excitation of local adrenergic fibers. The sinus deceleration to higher doses of phentolamine was not blocked either by atropine or by tetrodotoxin. It suggests that phentolamine has a direct depressive effect on the SA node at extremely high dose levels.

Animals↗
PubMed1975

Effect of apomorphine on the canine SA node.

A constant pressure perfusion of the sinus node artery was performed in 10 in situ and in 3 isolated SA node preparations. The selective administration of apomorphine caused a negative chronotropic effect which was not blocked by treatment with atropine. The sinus deceleration was usually produced by apomorphine, 10-300 mug, while sinus irregularity and finally atrioventricular nodal rhythm in the in situ preparation or sinus arrest in the isolated one resulted from doses above 1 mg. In the in situ preparation at a higher dose from 300 mug to 1 mg, a slight sinus acceleration was occasionally induced following sinus deceleration; In this time, a fall in blood pressure was usually observed; This acceleration response to apomorphine was inhibited by propranolol. From these results, it is concluded that apomorphine induces direct depressive action on the SA node and, in extremely high doses, a slight sinus acceleration may be induced by reflex mechanism.

Animals↗
PubMed1987

The first heart sound in normal and pathological conditions.

Considerations of the physical basis of cardiac contraction and sound generation explain the mechanism of the first sound. Older theories examining this sound as the result of valve closure or stiffening are refuted. It has been demonstrated that the normal first sound originates in the left ventricle alone and that accelerations and decelerations, "timed" by mitral and aortic valves events, are its cause. Three components have been recognized in the first sound: a occurs when the left ventricular wall and septum have reached a certain tension; b when the aortic valve opens; c when the peak of the aortic pulse has been reached. The ventricular septum is an integral and essential part of the left ventricle. In left bundle branch block, abnormal activation of the septum transforms this into a passive structure resulting in a slower rise of left ventricular pressure and a longer isovolumic period. This causes a small and delayed first sound, whose components, however, are still separated by normal intervals. In right bundle branch block, the first sound has a normal amplitude and its components are separated by normal intervals. If there is a larger late component, it is a c component, similar to that of normal elderly subjects. A larger c component may also be found in atrial septal defect. The cannon sound of AV block is caused by more rapid deceleration due to higher atrial pressure at the onset of ventricular contraction resulting in intense vibrations. The first sound of arrhythmias varies in the different conditions and even in different subjects, due to the effect of several variable factors. Elevated left atrial pressure, stiffening of the mitral valve in mitral stenosis, causes a slow onset and a more rapid rise of LV pressure. This results in a delayed, but larger, first sound. The action of catecholamines on the myocardium dramatically increases the first sound. The latter can be considered as an index of contractility and may be of great interest during stress tests.

Heart↗
PubMed1998

Right heart flow dynamics after tricuspid valve annuloplasty. Characteristics and time course.

To evaluate the effect of tricuspid annuloplasty (TAP) on right heart flow dynamics, we analyzed tricuspid inflow velocity pattern, jugular venous pulse and color Doppler flow signal of tricuspid regurgitation (TR) before and after surgery in 16 patients who underwent TAP (TAP group). Cardiac rhythm was atrial fibrillation in all patients. Twelve patients with lone atrial fibrillation served as controls (AF group). Patients in the TAP group were studied before and serially after surgery with a mean follow-up period of 2.7 years. TAP was performed according to the modified De Vega technique in all patients. In a comparison of the most recent data in the TAP group and the data in the AF group, the maximum tricuspid inflow velocity was significantly increased, and both the deceleration time of the tricuspid inflow velocity wave and the y-h interval of the jugular venous pulse were significantly prolonged in the TAP group compared to the AF group. Immediately after surgery, in the TAP group, the area of the TR jet was markedly decreased, and the deceleration time of the tricuspid inflow velocity wave was significantly prolonged compared to those before surgery. The area of the TR jet was dramatically decreased and remained small during the follow-up period. Thus, TAP may produce mild tricuspid stenosis but may also confer sustained preventive effects against TR.

Adult↗
PubMed2003

Neuroimaging of intraparenchymal lesions predicts outcome in shaken baby syndrome.

OBJECTIVE: Studies of long-term outcome on nonaccidental head injury (NAHI) in young children have shown severe neurodevelopmental sequelae in most cases. For improving the knowledge of outcome and for identifying prognostic factors, additional clinical and cerebral imaging data are needed. The aim of this study was to describe clinical and imaging features over time and to consider their value for predicting neurodevelopmental outcome. METHODS: A retrospective medical record review was conducted of 23 children with confirmed NAHI, for whom an extended follow-up of 2.5 to 13 years (mean: 6 years) was contemplated. Glasgow Coma Scale scores, severity of retinal hemorrhages, presence of skull fractures, cranial growth deceleration, and sequential neuroimaging data (computed tomography and/or magnetic resonance imaging) were compared with patterns of clinical evolution assessed by the Glasgow Outcome Scale. RESULTS: Clinical outcome showed that 14 (61%) children had severe disabilities, 8 (35%) had moderate disabilities, and 1 (4%) was normal. A low initial Glasgow Coma Scale score, severe retinal hemorrhages, presence of skull fracture, and cranial growth deceleration were significantly associated with poor developmental outcome. Eighteen of the 23 patients had abnormal magnetic resonance imaging scans. This examination disclosed atrophy when performed beyond 15 days of injury. Atrophy seemingly resulted from various brain lesions, namely, contusions, infarcts, and other lesions within the white matter. Presence of intraparenchymal brain lesions within the first 3 months was significantly associated with neurodevelopmental impairment. Severity of motor and cognitive dysfunctions was related to the extent of intraparenchymal lesions. CONCLUSIONS: Early clinical and radiologic findings in NAHI are of prognostic value for neurodevelopmental outcome.

Atrophy↗