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Biomedical subjects

B S Kisilevsky

Publications and source records attributed to B S Kisilevsky.

18 recordsLinked to original sources
PubMed2005

Maternal cardiac autonomic function and fetal heart rate in preeclamptic compared to normotensive pregnancies.

BACKGROUND: Preeclampsia during pregnancy increases a woman's risk of cardiovascular disease in two ways. Women who develop preeclampsia are at increased risk for the development of hypertension and cardiovascular disease later in life. As well, fetal adaptations (e.g., growth restriction) may lead to the development of cardiovascular risk factors (e.g., obesity, increased cholesterol) in the offspring. Although atypical maternal cardiac autonomic function has been reported in preeclampsia, to date, its effects on fetal cardiac function have not been determined. PURPOSE: To characterize the pattern of short-term maternal cardiac autonomic modulation and spontaneous fetal heart rate changes in preeclamptic compared to normotensive women and to determine the relationship between them. METHOD: Twenty-seven mother-fetal pairs (n = 9 preeclamptic, n = 18 normotensive) at 32 to 40 weeks gestation were tested on one occasion. Maternal autonomic modulation of heart rate was measured for 20 minutes using electrocardiographic and beat-by-beat arterial systolic blood pressure recordings. Simultaneously, spontaneous fetal heart rate was obtained using a cardiotachograph. Women's cardiac autonomic responses to orthostatic stress were obtained for five minutes in a standing position. RESULTS: Comparisons of maternal cardiac measures in the preeclamptic versus the normotensive group showed that the preeclamptic group had a decreased parasympathetic nervous system indicator and an increased sympathetic nervous system indicator with increasing gestation. In response to orthostatic stress, women in both groups showed a similar increase in arterial systolic blood pressure and a decrease in parasympathetic nervous system indicator and R-R interval when standing compared to lying. Fetuses in the normotensive compared to the preeclamptic group had more spontaneous fetal heart rate accelerations; the greater the decrease in the parasympathetic nervous system indicator from lying to standing, the greater the number of fetal heart rate accelerations. CONCLUSIONS: These findings serve to further our understanding of the cardiovascular pathophysiology of preeclampsia in both the mother and the fetus. Women who develop preeclampsia during pregnancy show atypical autonomic nervous system modulation of heart rate that is associated with a decrease in spontaneous fetal heart rate accelerations in late gestation. Implications for cardiovascular nursing practice include the monitoring of maternal cardiac autonomic function during pregnancy, especially during standing, as well as a need for continued surveillance of maternal cardiovascular function following pregnancy. The negative effect on fetal heart rate accelerations has implications for the interpretation of standardized obstetrical tests of fetal well-being.

Adult↗
PubMed2002

An exploratory study of fetal behavior at 33 and 36 weeks gestational age in hypertensive women.

The relationship between maternal blood pressure (BP) and fetal behaviors as well as differential spontaneous and vibroacoustic elicited fetal behaviors were examined in hypertensive (n = 21) compared to normotensive (n = 22) women at 33 and 36 weeks gestational age (GA). Maternal BP was negatively related to GA at birth and birth weight. On average, fetuses of hypertensive women were born 2 weeks earlier (38 weeks GA) and 340 g lighter. Maternal systolic BP was negatively related to the number of spontaneous body movements observed on ultrasound scan over 20 min and the magnitude of the fetal heart rate (FHR) acceleration elicited by a vibroacoustic stimulus. At 36 weeks GA, vibroacoustic stimulation elicited differential responding with fetuses in the hypertensive compared to the normotensive group having fewer body movements, a lower magnitude of FHR acceleration, and a lack of cardiac-body movement coupled responses. These findings suggest a relationship between maternal BP and fetal behaviors and differential functional development of sensory-motor response systems which need to be characterized in the subgroups of hypertensive disorders observed during pregnancy.

Acoustic Stimulation↗
PubMed2001

Maturation of fetal heart rate and body movement in 24-33-week-old fetuses threatening to deliver prematurely.

Maturation of spontaneous cardiac and body movement behavior from 24 to 33 weeks gestational age was characterized prospectively in 168 high-risk fetuses threatening to deliver prematurely. Forty-eight, low-risk fetuses delivering as healthy full-term infants served as a comparison group. Fetuses were classified on the basis of gestational age at time of testing and newborn outcome following delivery (high-risk: premature compromised, premature healthy, term healthy infant; low-risk term healthy). In the high-risk group, the average fetal heart rate was greater and decreased over gestation from 148 to 140 bpm, regardless of outcome. In the low-risk group, it decreased from 145 to 138 bpm. In high- and low-risk groups, the average number of heart rate accelerations greater than or = 15 bpm increased over gestation from 2-3 to 8 while the average number of maternally perceived movements decreased. It was concluded that maturational changes in spontaneous fetal heart rate and maternally perceived body movements in fetuses threatening to deliver prematurely parallel those of low-risk fetuses.

Analysis of Variance↗
PubMed2000

Maturation of human fetal responses to airborne sound in low- and high-risk fetuses.

The purpose of the study was to characterize the onset and maturation of airborne sound-elicited responses in low- and high-risk preterm fetuses. In Study 1, a total of 91 low-risk fetuses at 27, 30, 33, and 36 weeks GA received three sound trials at 90, 100, 105 and 110 dB and three no-stimulus control trials. The onset of cardiac acceleration and body movement responses occurred at 30 weeks GA. Maturation of the cardiac response was observed with a decrease in threshold from 105-110 dB at 33 weeks GA to 100-105 dB at 36 weeks GA. In Study 2, the procedure was similar except that the 43 high-risk fetuses at 27, 30 and 33 weeks GA did not receive sounds at 90 dB. For the high-risk fetuses, the onset of cardiac and motor responses also occurred at 30 weeks GA. At 33 weeks GA, those high-risk fetuses subsequently born at term showed an increased magnitude of the cardiac acceleration response compared to low-risk fetuses. The results indicate that both low- and high-risk fetuses begin responding to sounds at the same gestational age. Differential responses observed over gestation in the high-risk group most likely indicate differential functional development of the auditory-response system.

Acoustic Stimulation↗
PubMed2000

Music modulates behaviour of premature infants following heel lance.

The physiological and behavioural effects of music during recovery from heel lance were examined in 14 preterm infants at 29 to 36 weeks post-conceptual age (PCA). Infants were tested on 2 occasions: during a music condition and during a no-music control condition. Each condition was videotaped during 3 periods: baseline, heel lance, and recovery. Infants were divided into 2 age groups for data analyses: less than and greater than 31 weeks PCA. Mixed model ANOVAs showed that heel lance elicited a stress response (i.e., increased heart rate, decreased oxygen saturation, increased state-of-arousal, and increased facial actions indicative of pain) in both age groups. The stress response was greater in the older group. During recovery, the older group had a more rapid return of heart rate, behavioural state, and facial expressions of pain to baseline levels in the presence of compared to the absence of music. It was concluded that music is an effective NICU intervention following a stress-provoking stimulus in infants older than 31 weeks PCA.

Heel↗
PubMed1999

Maturation of body and breathing movements in 24-33 week-old fetuses threatening to deliver prematurely.

Maturation of spontaneous fetal body and breathing movements of 24- to 33-week-old fetuses in 168 pregnancies threatening to deliver prematurely were examined on the basis of newborn outcome (premature compromised, premature healthy, term healthy). Maturation of fetuses in 60 low-risk pregnancies delivering as healthy full-term infants served as a normative comparison group. Each fetus was observed for 30 min; the amount of body and breathing movements were noted and an estimation of amniotic fluid volume was made. The pattern of behavioural maturation was similar for all outcome groups; with advancing gestation there was a decrease in body movements and an increase in breathing movements. Both reduced activity levels and advanced behaviours were observed in the high-risk outcome groups. The high-risk fetuses had reduced levels of body movements which increased with better outcome and, an earlier onset of increased amounts of breathing, occurring at 30 weeks in contrast to 33 weeks for the comparison group. In the presence of ruptured membranes, those high-risk fetuses who were born prematurely had less breathing compared to those who delivered at term. Similar maturation patterns among high- and low-risk outcome groups suggests normal/typical functional development in the high-risk fetal groups. The observed differential behaviours were associated with prematurity and most likely associated with events leading to premature labour.

Amniotic Fluid↗
PubMed1999

Newborns discriminate schematic faces from scrambled faces.

Newborn attention to, and discrimination of, facelike patterns was examined in three experiments employing 35 one- to three-day-old infants. Differential eye tracking and head turning to three moving stimuli (a schematic face, a scrambled face, and a luminance-matched blank) were measured in two of the three experiments. The newborns turned their eyes and heads farther to follow patterned stimuli, containing facelike features, than to a luminance-matched blank, but they did not turn farther to a stimulus with the features arranged in a facelike manner compared to features scrambled. A third experiment tested newborns' ability to discriminate between the facelike and scrambled face patterns. Using an infant-controlled procedure, infants showed similar initial fixation times and similar numbers of trials to reach a 60% response decrement criterion to both patterned stimuli. Following habituation, novelty responding indicated that infants discriminated between the schematic face and the scrambled face patterns. Although infants did not show a preference for a facelike stimulus compared to a features-scrambled pattern in the present experiments, they could discriminate the two patterns based on the internal arrangement of the facial features.

Discrimination, Psychological↗
PubMed1999

Fetal behavior in diabetic and nondiabetic pregnant women: An exploratory study.

To characterize differential behavior and the relationship between maternal blood glucose levels and behavior in fetuses of diabetic (n = 10) and nondiabetic (n = 20) women at 33 and 36 weeks gestational age (GA), spontaneous changes in fetal heart rate (FHR), body and breathing movements, and vibroacoustic stimulus elicited (3 stimulus/3 no-stimulus control trials) FHR changes and body movements were compared. Measures of maternal blood glucose levels were obtained immediately following testing; measures varied within normal range. Spontaneous behaviors showed no differences between groups and no relationship to maternal blood glucose levels. Sensory stimulation elicited similar average peak FHR accelerations (M = 17. 1/20.0 BPM) and average movement scores (2.0/2.6) across groups. In the diabetic group at 33 weeks GA, the nature of the FHR change over time, showed more varied patterns of response, a shorter latency to peak acceleration, was less organized, and less mature; as average maternal blood glucose levels increased, elicited body movements decreased. These findings suggest immaturity and differential functional development of sensory-motor response systems in fetuses of diabetic mothers.

Arousal↗
PubMed1998

The still-face effect in Chinese and Canadian 3- to 6-month-old infants.

Studies conducted in China examining cross-cultural differences in 3- to 6-month-olds used the still-face paradigm. In each study, 20 infants were in the experimental group (normal, still-face, normal interactions) and 20 in the control (3 normal periods). In Study 1, infants interacted with either their mother or their father; they looked and smiled less to the still-face of both parents. In Study 2, infants interacted with both their mother and a stranger, with order counterbalanced. Experimental groups showed similar still-face effects to both adults. The control group responded similarly to the stranger in both orders but responded less to their mother when she interacted 2nd. The data were compared with archival data from Canadian infants. Although Chinese infants took longer to begin smiling, responding was similar in both cultures, despite differences in mothers' behavior: Chinese mothers played with the infants' arms; Canadian mothers played with the legs.

Adult↗
PubMed1997

Swaddling after heel lance: age-specific effects on behavioral recovery in preterm infants.

We examined responses of preterm infants to swaddling after a heel lance. Fifteen preterm infants from two postconceptional age (PCA) groups (Group 1: n = 7, PCA < 31 wk; Group 2: n = 8, PCA > or = 31 wk) were observed for 30 minutes during blood sampling followed by routine care; blood sampling followed by swaddling; and no blood sampling and routine care. In both groups, blood sampling resulted in concurrent increases in heart rate and state of arousal, in negative facial displays, and in reductions in blood oxygensaturation. After the blood was drawn, infants less than 31 weeks PCA exhibited an immediate and spontaneous return to behavioral patterns similar to those observed during the no-blood-sample condition, regardless of treatment condition. Infants 31 weeks PCA or older exhibited protracted behavioral disturbance that was significantly reduced by the use of swaddling. We discuss the significance of these findings.

Age Factors↗
PubMed1995

A nursing research utilization strategy for staff nurses in the acute care setting.

The importance of research-based nursing practice is well recognized. However, typically, strategies to incorporate research findings into nursing practice have not been evaluated in terms of staff nurse outcomes. Thus, the purpose of this project was to evaluate the effectiveness of a research utilization strategy for staff nurses in the neonatal intensive care unit of a community teaching hospital. This project was intended to serve as a model for the incorporation of research findings into nursing practice on other nursing units in the acute care setting.

Adult↗
PubMed1993

Neonatal movement response decrement and recovery to sounds as a function of stimulus intensity.

Response decrement, novelty response, and dishabituation of body movements to repeated presentations of a white noise stimulus of 66, 76, and 86 dB were studied in 89, 2-3-day-olds in the first epoch of active-quiet sleep following a feeding. Newborns receiving the 86 dB repeating stimulus had greater movement scores compared to those receiving the 76 dB intensity who, in turn, had greater movement scores than those receiving the 66 dB intensity. All groups demonstrated movement response decline following repeated stimulation and a novelty response was observed when either a 66 or 76 dB repeating stimulus was increased to 86 dB. A novelty response was not observed when intensity was decreased and dishabituation was not observed following a novelty response. For a white noise stimulus, these findings are more consistent with the selective adaptation than the habituation explanation of neonatal response decrement to repeated auditory stimulation.

Acoustic Stimulation↗
PubMed1993

Vibroacoustic-induced fetal movement: two stimuli and two methods of scoring.

OBJECTIVE: To determine whether the fetal movement response elicited by vibroacoustic stimulation depends upon the vibrator and the method used to judge movement. METHODS: Two methods of obtaining elicited fetal movement responses--maternal perceptions and ultrasound scan observations--were compared using two different vibroacoustic stimuli in 16 low-risk term pregnancies. RESULTS: Analyses of response over trials showed that the percentage of agreement between ultrasound scan observations and maternal perceptions varied (52-96%) across stimuli. The mothers perceived 64% less movement when vibrator 1 was used and 14% less movement response with vibrator 2. Analyses of average movement scores across subjects showed similar results. Vibrator 1 elicited significantly fewer maternal perceptions of fetal movement compared with ultrasound scan observation (an average of 0.8/3 compared with 2.3/3 movements per subject, respectively). For vibrator 2, there were no differences in average movement scores obtained by maternal perception and ultrasound scan observation (an average of 2.4/3 versus 2.8/3, respectively). CONCLUSION: The stimulus used in vibroacoustic stimulation testing influences the reliability of maternal movement perceptions as compared with ultrasound scan observations.

Acoustic Stimulation↗
PubMed1992

Maturation of human fetal responses to vibroacoustic stimulation.

Maturation of human fetal response to vibroacoustic stimulation was examined in 60 fetuses from 23 to 36 weeks gestational age. Subjects received vibroacoustic or no-stimulus control trials (randomly assigned) while fetal heart rate (FHR) was recorded and movement was observed on real-time ultrasound scan. Initially, at 26-28 weeks, a small FHR deceleration response occurred; subsequently, FHR acceleration responses occurred. From 29 weeks, 83%-100% of subjects responded with an FHR acceleration > or = 10 BPM on the first vibrator trial and accelerations were observed on 83%-92% of all vibrator trials. From 26 to 36 weeks the percentage of fetuses responding with movement on the first vibrator trial increased from 58% to 100%; on all vibrator trials responses increased from 53% to 94%. It was concluded that maturation of human fetal response to vibroacoustic stimulation begins at about 26 weeks gestation, increases steadily over a 6-week period, and reaches maturity at about 32 weeks.

Acoustic Stimulation↗
PubMed1991

Maternal and ultrasound measurements of elicited fetal movements: a methodologic consideration.

Two methods of evaluating fetal movement responses elicited by vibroacoustic stimulation--maternal perceptions and ultrasound scan observations--were compared in 58 low-risk and 35 high-risk pregnancies from 23-36 weeks' gestation. Maternal perception of vibrator-elicited fetal movement was poor compared with ultrasound scan observation. Regardless of gestational age or risk status, the mothers perceived 27-75% fewer movements than observed with ultrasound scan. In addition, maternal movement perceptions on vibrator versus no-stimulus control trials were not reliable until 29-32 weeks' gestation, with the percentage of movement responses increasing across gestation from 11 to 48%. In contrast, ultrasound scan observations of movement were reliable on vibrator compared with no-stimulus control trials from 26 weeks, with the percentage of movement responses increasing from 22% at 23-25 weeks to 94% at 35-36 weeks. We conclude that maternal perceptions of fetal movements cannot be substituted for ultrasound scan observations for accurate assessment of fetal movements during vibroacoustic stimulation testing.

Adult↗
PubMed1990

Maturation of responses elicited by a vibroacoustic stimulus in a group of high-risk fetuses.

The study was designed to characterize the changes in fetal heart rate (FHR) and movement responses in a group of high-risk fetuses to address the question of differential responding as a function of risk status. The study included 36 women admitted to hospital with threatened preterm labour (e.g., contractions, bleeding, premature rupture of membranes) with singleton pregnancies between 23 and 34:6 weeks gestational age. Each fetus received three vibration and three no-stimulus control trials, intermixed and randomly presented. Vibration trials consisted of a 2.5-second (s) application of the tip of a battery-powered, hand-held commercial vibrator to the maternal abdomen over the site of the fetal head while the FHR was recorded continuously and movements were scored from a cross section of the infant's abdomen viewed with a real-time ultrasound scanner. FHR within 20 s and movements within 5 s of trial onset were scored blind as to vibration or control trial. Repeated measures ANOVA demonstrated that fetuses responded to vibration with FHR accelerations from 29 weeks and movements from 26 weeks. Although movements increased with increasing gestational age, the mean peak FHR acceleration showed no significant increase from 29 to 32 weeks. From 29 weeks, the latency to response was 5 s and the peak of the acceleration occurred at about 10 to 12 s. At 26-28 weeks, a small but reliable cardiac deceleration occurred at about 5 s after stimulus onset. These preliminary findings suggest a maturation of fetal sensitivity to vibroacoustic stimulation which is similar for groups of low-risk and high-risk fetuses. However, the variability in outcome--from preterm newborn death to "healthy" term delivery--in the high-risk group suggests that the sample may be heterogeneous.

Acoustic Stimulation↗
PubMed1989

Human fetal responses to sound as a function of stimulus intensity.

The effect of stimulus intensity on fetal heart rate (FHR) acceleration and body movement responses was evaluated in term fetuses in a two-stage study. During the first stage (N = 30), a pink noise played at 110 or 105 dB elicited a greater mean peak FHR acceleration than when played at 100 dB. Movement scores indicated that the 110-dB noise elicited more movements than the 105-dB noise which, in turn, elicited more than the 100-dB noise. The FHR acceleration and movement responses elicited on 100-dB sound trials could not be differentiated from spontaneous activity on no-sound control trials. During the second stage (N = 93), the 110-dB pink noise elicited a mean peak FHR acceleration of 14 beats per minute on the first stimulus presentation, replicating the findings of the first stage. Furthermore, the percentage of 110-dB stimulus/control trials in which there was an FHR acceleration greater than ten beats per minute (stage 1: 57%/10%; stage 2: 58%/24%) and movement response (stage 1: 50%/7%; stage 2: 52%/7%) was virtually identical in the two stages. We conclude that fetal response varies as a function of stimulus intensity and that the threshold for response to an air-borne pink noise is between 100-105 dB. These findings have implications for stimulus selection and control procedures in acoustic stimulation testing.

Acoustic Stimulation↗