Changes In Maternal Heart Rate Research Articles

Changes in maternal heart rate in delayed post-partum preeclampsia

AimDelayed-onset postpartum preeclampsia (PET) is defined as a new diagnosis of preeclampsia presenting 48 h to 6 weeks postpartum. This disorder is infrequent and associated with a higher incidence of complications as compared to antepartum PET. There seems to be a need to further characterize this disorder. The aim of the study was to investigate the difference of maternal heart rate in women with delayed onset postpartum preeclampsia as compared to healthy controls.MethodsThe medical files of all women who were readmitted with delayed onset postpartum preeclampsia during 2014–2020 were reviewed. Data on maternal physiological characteristics were compared to healthy control group of women at the same post-partum day, with uncomplicated pregnancies.ResultsIncluded 45 women with the diagnosis of delayed onset of preeclampsia at 6.3 ± 2.86 post-partum day. As compared to controls (n = 49), women with delayed post-partum were older, 34.6 ± 5.4 vs. 32.3 ± 4.7 years, p = 0.003. There were no differences between groups regarding maternal gravidity, parity, BMI (kg/m2) or Hb level at delivery day. Women with delayed post-partum preeclampsia had lower mean pulse rate as compared to controls, 58 ± 15 bpm vs. 83 ± 11.6 bpm, respectively, P < 0.0001. Only 17% of the women in the delayed onset group had pulse rate above 70 bpm as compared to 83% in the control group.ConclusionsMaternal low heart rate in cases with delayed onset of post-partum preeclampsia is an important clinical characteristic that may reflect baroreceptors response to maternal hypertension.

Changes in Maternal Heart Rate and Autonomic Regulation following the Antenatal Administration of Corticosteroids: A Secondary Analysis.

While the effect of antenatally administered corticosteroids on fetal heart rate (HR) and heart rate variability (HRV) is well established, little information is available on how these drugs affect maternal physiology. In this secondary analysis of a prospective, observational cohort study, we quantify how corticosteroids affect maternal HR and HRV, which serve as a proxy measure for autonomic regulation. Abdominal ECG measurements were recorded before and in the five days following the administration of betamethasone-a corticosteroid commonly used for fetal maturation-in 46 women with singleton pregnancies. Maternal HR and HRV were determined from these recordings and compared between these days. HRV was assessed with time- and frequency-domain features, as well as non-linear and complexity features. In the 24 h after betamethasone administration, maternal HR was significantly increased (p &lt; 0.01) by approximately 10 beats per minute, while HRV features linked to parasympathetic activity and HR complexity were significantly decreased (p &lt; 0.01 and p &lt; 0.001, respectively). Within four days after the initial administration of betamethasone, HR decreases and HRV features increase again, indicating a diminishing effect of betamethasone a few days after administration. We conclude that betamethasone administration results in changes in maternal HR and HRV, despite the heterogeneity of the studied population. Therefore, its recent administration should be considered when evaluating these cardiovascular metrics.

Fetal and maternal responses to yoga in the third trimester

Objective: The primary purpose of this study was to examine maternal and fetal responses to a typical, moderate-intensity yoga session in healthy pregnant women during the third trimester using continuous monitoring.Methods: This prospective observational study in low-risk, pregnant women used the Monica AN24 Abdominal ECG wireless maternal-fetal monitor to measure fetal heart rate, maternal heart rate, and uterine activity during a prenatal yoga session. Sessions included 4 time periods: (1) 20-minute rest, (2) 50 minutes standard prenatal yoga, (3) 10-minute meditation, (4) 20-minute recovery. Data were continuously recorded throughout the entire session, stored at 0.25-second intervals, and then averaged over 5-minute intervals. To evaluate changes over time, overall means for the four time periods (rest, yoga, meditation, recovery) were compared using one-way ANOVA with repeated measures. Post-hoc pairwise comparisons (Tukey’s) were used to probe significant differences between the four time points. Statistical significance was reached at p < .05.Results: Twenty participants were enrolled; 19 completed the yoga session. Mean gestational age was 35 weeks and 6 days (range of 32–0/7 to 38–6/7) with an average participant age of 32 ± 2.7 years. Maternal heart rates significantly increased during the yoga period (102 ± 11 bpm) compared to rest (90 ± 10), meditation (85 ± 12), and recovery (88 ± 10) (p < .01). The maximum maternal heart rate reached during the yoga session was 125 ± 13 bpm. While fetal heart rates fluctuated slightly over the course of the yoga session, there were no significant fetal heart rate decelerations to suggest deleterious fetal effects. There were no statistically significant differences among resting (138 ± 14 bpm), yoga (137 ± 11 bpm), meditation (139 ± 7 bpm), or recovery (135 ± 22 bpm) fetal heart rates (p = .814). Uterine activity was significantly greater during the yoga period compared with the other time points (p < .001).Conclusion: Yoga can be recommended for low-risk women during pregnancy as no adverse fetal or maternal heart rate changes were observed during a typical prenatal yoga session.

Prediction of Hypotension During Spinal Anesthesia for Elective Cesarean Section by Altered Heart Rate Variability Induced by Postural Change

(Int J Obstet Anesth. 2017;29:34–38) Hypotension is a common problem during cesarean deliveries performed under spinal anesthesia. Identifying patients at risk for spinal-induced hypotension could be useful for the management of anesthesia as maternal hypotension can have deleterious effects on both the mother and child. Previous work has found maternal heart rate variability to be useful in predicting which parturients will develop hypotension during spinal anesthesia. It has also been suggested that changes in maternal heart rate with changes in maternal position could be predictive of patients at risk for developing hypotension. This study was devised to assess whether heart rate variability changes caused by maternal position changes could be a predictor of hypotension during spinal anesthesia.

Dexmedetomidine in preeclamptic patients undergoing caesarean section under general anesthesia

Background Dexmedetomidine is used as a sedative in surgical and other procedures in nonintubated adult and pediatric patients. It has been successfully used in laboring parturients as it provides maternal hemodynamic stability and anxiolysis. Aim The aim of this study is to assess the effects of dexmedetomidine in preeclampsia patients under general anesthesia as regards: pressor response to laryngoscopy and intubation, doses of anesthetic agents, muscle relaxants and narcotics, uterine contractility and neonatal effect, postoperative recovery, and postoperative analgesic requirements. Patients and methods This study was carried out on 60 parturients with preeclampsia who were scheduled for elective caesarean delivery. Patients were divided randomly into two groups: DEX group, patients received 1 µg/kg intravenous dexmedetomidine 10 min before induction and a maintenance dose with 0.4 µg/kg/h during surgery, and the control group: patients did not receive dexmedetomidine (n=30/group). Changes in maternal heart rate, mean arterial blood pressure, time from induction to delivery, full anesthesia time (especially during stress of intubation), and depth of anesthesia were monitored by bispectral index. The total dose of propofol, rocuronium and fentanyl consumption, uterine contraction after placental delivery, Apgar score, postoperative recovery profile, postoperative pain, and postoperative analgesia were also assessed. Results Heart rate was significantly lower in the DEX group than in the control group. The mean arterial blood pressure was significantly lower in the DEX group than in the control group from the induction till after extubation. Also there was significant decrease in the total consumption of propofol, fentanyl, and muscle relaxant in the DEX group than in the control group, while both groups were comparable in uterine contraction, Apgar score, and awareness. Conclusion This study suggests the effective use of dexmedetomidine in pre-eclamptic patients undergoing elective cesarean as it stabilizes the maternal hemodynamic parameters during intubation and after intubation with negligible effect on the fetus.

Prediction of hypotension during spinal anesthesia for elective cesarean section by altered heart rate variability induced by postural change

BackgroundMaternal hypotension is a common complication during cesarean section performed under spinal anesthesia. Changes in maternal heart rate with postural changes or values of heart rate variability have been reported to predict hypotension. Therefore, we hypothesized that changes in heart rate variability due to postural changes can predict hypotension. MethodsA total of 45 women scheduled to undergo cesarean section under spinal anesthesia were enrolled. A postural change test was performed the day before cesarean section. The ratio of the power of low and high frequency components contributing to heart rate variability was assessed in the order of supine, left lateral, and supine. Patients who exhibited a ⩾two-fold increase in the low-to-high frequency ratio when moving to supine from the lateral position were assigned to the postural change test-positive group. ResultsAccording to the findings of the postural change test, patients were assigned to the positive (n=22) and negative (n=23) groups, respectively. Hypotension occurred in 35/45 patients, of whom 21 (60%) were in the positive group and 14 (40%) were in the negative group. The incidence of hypotension was greater in the positive group (P<0.01). The total dose of ephedrine was greater in the positive group (15±11 vs. 7±7mg, P=0.005). The area under the receiver operating characteristic curve was 0.76 for the postural change test as a predictor of hypotension. ConclusionThe postural change test with heart rate variability analysis may be used to predict the risk of hypotension during spinal anesthesia for cesarean section.

Study on the effect of dexmedetomidine in reducing hemodynamic responses to general anesthesia for elective cesarean section in patients with pre-eclampsia

Background Because of the effect of dexmedetomidine (DEX) in hemodynamic stability, it was started as a sedative before and during surgical and other procedures in nonintubated adult and pediatric patients. Since 2009 DEX has been successfully used in laboring parturients. It provides maternal hemodynamic stability, anxiolysis, and stimulation of uterine contractions. Studies have shown that DEX has high placental retention and does not cross the placenta, and there is lower incidence of fetal bradycardia. We hypothesized that dexmedetomidine would be effective in reducing the maternal hemodynamic responses to elective cesarean section in pre-eclamptic patients without adverse neonatal effects. Patients and methods The present study included 40 parturients with pre-eclampsia who were planned for elective cesarean delivery for different indications under general anesthesia. The patients were divided in two groups and they were selected randomly to receive either fentanyl (control group) or 0.4 μg/kg/h intravenous DEX 10 min before induction (n = 20 per group). Changes in maternal heart rate, mean blood pressure, time from induction to delivery, the full anesthesia time, uterine contraction after placental delivery, umbilical blood gas parameters, and sedation scores were recorded. Results The heart rate in the DEX group was lower than that in the fentanyl group. Patients in the dexmedetomidine group had statistically significantly lower change in mean arterial blood pressure, whereas patients taking fentanyl showed much higher mean arterial blood pressure from induction until 5 min after extubation. Further, the dexmedetomidine group showed greater uterine contraction, but there was no difference between the two groups in terms of Apgar score at 1 and 5 min, NACS below 35, and umbilical blood gas analysis. Conclusion It can be concluded that DEX is effective in pre-eclamptic patients undergoing elective cesarean as it stabilizes the maternal hemodynamic parameters with negligible effect on the fetus.

Effect of maternal position and uterine activity on periodic maternal heart rate changes before elective cesarean section at term.

Because little is known about the effects of maternal position on periodic changes in the maternal heart rate (MHR) in late pregnancy, a prospective observational study was done at Tygerberg Academic Hospital in Cape Town. Pregnant women admitted for elective cesarean section were studied to determine the effect of changes in position on the maternal and fetal heart rates (FHR) and maternal blood pressure. Continuous transabdominal non-invasive recording of MHR, FHR patterns and uterine activity was done for 1 h in 119 women, using the AN24 device from Monica Health Care. Maternal position was changed every 15 min from lateral to supine, then to the other lateral position and finally supine again. Blood pressure was measured in the left arm and left lower leg three times during each 15-min period. MHRs were four beats per minute slower in the left lateral position than in the right lateral position. Periodic MHR changes were seen in 13 (10.9%) women. Most of these (84.6%) were associated with uterine activity and not with maternal position. No changes in FHR patterns were observed after position changes. In a subgroup of pregnant women at term, uterine activity was associated with periodic decelerations of the MHR. In low risk pregnancies there seems to be no effect on the FHR pattern. Implications for the compromised fetus have not yet been investigated.

Study of the Effect of Dexmedetomidine in Reducing Hemodynamic Responses to General Anesthesia for Elective Cesarean Section in Patients with Preeclampsia

Background: Depending on the effect of dexmedetomidine in haemodynamic stability, it was started to be used as a sedative prior to and/or during surgical and other procedures in non-intubated adult and pediatric patients. In 2009, dexmedetomidine has been successfully used in laboring parturients. It provides maternal hemodynamic stability, anxiolysis, and stimulation of uterine contractions. Literature describes that dexmedetomidine has a high placental retention and does not cross the placenta, with less incidence of fetal bradycardia. We hypothesized that dexmamedetomidine would be effective in reducing the maternal hemodynamic responses to elective cesarean section in preeclmaptic patients without adverse neonatal effects. Methods: The series of the present study included forty parturients with preeclampsia who were planned for elective caesarean delivery for different indications under general anesthesia. The patients were divided in 2 groups and they were selected randomly to receive either fentanyl (control group), or 0.4 μg/kg/h intravenous dexmedetomidine 10 min before induction (n=20 per group). Changes in maternal heart rate, mean blood pressure, time from induction to delivery, the full anesthesia time, uterine contraction after placental delivery, umbilical blood gas parameters and Sedation scores were recorded. Results: The heart rate in the dexmedetomidine group was lower than that in fentanyl group, patients in dexamedetomidine group had statistically significant lower change in mean arterial blood pressure, while patients taken fentanyl showed much higher mean arterial blood pressure from the induction till 5 minutes after extubation, Also the dexamedetomidine group showed greater uterine contraction, while there was no difference between both groups in Apgar score at 1 and 5 minute, NACS<35 and the umbilical blood gas analysis. Conclusion: It could be concluded that, this study suggests the effective use of dexmedetomidine in preeclamptic patients undergoing elective cesarean as it stabilizes the maternal hemodynamic parameters with negligible effect on the fetus.

Phenylephrine versus ephedrine usage in the management of hypotension-induced spinal anaesthesia in pre-eclamptic patients undergoing caesarean section

Objective The aim of the current study is to assess and compare the effect of using phenylephrine and ephedrine for the prevention and treatment of maternal hypotension associated with induction of spinal anaesthesia in pre-eclamptic women undergoing a caesarean section. Study design This was a prospective randomized-controlled study. Patients and methods Sixty full-term pre-eclamptic patients, undergoing caesarean section under spinal anaesthesia, were divided into four groups: group 1 was administered 5 mg ephedrine intravenously and 5 mg boluses whenever there was maternal hypotension. Group 2 was administered 25 µg intravenous bolus phenylephrine and 25 µg boluses whenever there was maternal hypotension. Group 3 was administered a phenylephrine infusion at 25 µg/min; subsequently, the rate of infusion was adjusted according to systolic blood pressure (SBP). Group 4 was administered 15 ml/kg lactated ringer solution before spinal anaesthesia; subsequently, the rate of infusion was adjusted according to SBP. Results There was no statistically significant difference in the maternal heart rate changes, SBP changes, Doppler study of the uterine arteries, newborn blood pH and Apgar scores at 1 and 5 min between the four groups. Conclusion The use of an ephedrine or a phenylephrine infusion for the treatment of hypotension induced by spinal anaesthesia in pre-eclamptic patients yields comparable maternal and neonatal outcomes; further studies on a larger sample study are recommended to confirm our results.

Efficacy of dexmedetomidine in suppressing cardiovascular and hormonal responses to general anaesthesia for caesarean delivery: a dose–response study

BackgroundPreoperative dexmedetomidine administration blunts haemodynamic and hormonal responses to tracheal intubation and reduces anaesthetic requirements. We hypothesized that dexmedetomidine would reduce the maternal haemodynamic and hormonal responses to elective caesarean delivery without harmful neonatal effects. MethodsAfter ethical approval, 68 parturients scheduled for elective caesarean delivery under general anaesthesia were randomly allocated to receive either placebo, or 0.2, 0.4 or 0.6μg/kg/h intravenous dexmedetomidine (n=17 per group) 20min before induction. Anaesthesia was induced using a rapid-sequence technique with propofol and suxamethonium, and was maintained with 0.5–0.75 minimum alveolar concentration sevoflurane. Changes in maternal heart rate, mean blood pressure, minimum alveolar concentration sevoflurane, uterine tone, serum cortisol level, and Apgar scores, Neurologic Adaptive Capacity Scores and acid–base status were recorded. ResultsAfter induction, patients receiving dexmedetomidine had smaller increases in heart rate (P<0.001) than those in the placebo group. Patients who received 0.4 and 0.6μg/kg/h infusions of dexmedetomidine showed slower heart rates (−21.5% and −36%, respectively; P<0.001), lower mean blood pressures (−17% and −25%, respectively; P<0.001), sevoflurane minimum alveolar concentrations (−40% and −44.5%, respectively; P<0.001) and serum cortisol levels (−27% and −34.6%, respectively; P<0.001) and higher sedation scores for the first 15min after extubation and greater uterine tone (P<0.002). Apgar scores, NACS and acid–base status were similar in the four groups. ConclusionPreoperative administration of dexmedetomidine 0.4 and 0.6μg/kg/h is effective in attenuating the maternal haemodynamic and hormonal responses to caesarean delivery under sevoflurane anaesthesia without adverse neonatal effects.

Maternal cardiovascular function: longitudinal changes prior to and in pregnancy

Normal pregnancy is associated with profound changes in maternal heart rate (HR), peripheral blood pressure (BP) and cardiac output (CO) as early as 5-6 weeks. However, longitudinal changes in central...

Maternal heart rate changes during labour

Objectives Labour and delivery represent a considerable effort for pregnant women. Lack of aerobic fitness may limit pushing efforts during childbirth and represents increased cardiovascular strain and risk. Increasing prevalence of sedentary behaviour and lack of aerobic fitness may reduce heart rate reserve during labour. Study design We quantified maternal heart rate reserve (maximum heart rate minus resting heart rate) of 30 healthy pregnant women during labour and delivery and related it to habitual daily physical activity levels quantified during the third pregnancy trimester by the Pregnancy Physical Activity Questionnaire. Results Heart rates during labour reached values similar to those observed during moderate to heavy physical exercise. During active pushing one out of five women reached heart rates more than 90% of their heart rate reserve (188 ± 7 beats per min). Half of the women reached more than 70% of heart rate reserve (172 ± 14 beats per min). Physically inactive women used more of their heart rate reserve as physically more active women (87 ± 20% vs. 65 ± 12%, upper and lower tertile respectively, p < 0.05). Conclusions Use of heart rate reserve for the effort of labour is increased in physically inactive women and may potentially limit the intensity and duration of pushing efforts. Such higher cardiovascular strain in physically less active women may represent increased cardiovascular risk during labour.

Attenuation of maternal psychophysiological stress responses and the maternal cortisol awakening response over the course of human pregnancy

The effects of maternal stress during pregnancy may depend, in part, on the timing in gestation of the occurrence of stress. The aim of the present study was to examine the effect of stage of gestation on maternal psychophysiological responses to stress using a standardized laboratory paradigm and on the cortisol response to awakening (CAR). A longitudinal design was employed to quantify maternal psychophysiological stress reactivity [changes in heart rate (HR), blood pressure, salivary cortisol, and psychological distress in response to the trier social stress test (TSST)] and the CAR at approximately 17 and 31 weeks gestation in a sample of 148 women. To account for the possible effects of habituation when being exposed to the same stress protocol twice, a non-pregnant comparison group (CG, N = 36) also underwent these assessments at two time points, with a comparable time interval between the assessments. In both groups, the TSST elicited significant changes in maternal HR, mean arterial pressure, and psychological distress levels but not a significant increase in cortisol levels. Among the pregnant women (pregnant group(PG)), the stressor-induced increases in HR, blood pressure, and psychological distress were significantly lower at the second (31 weeks gestation) compared to the first (17 weeks gestation) assessment of pregnancy (all p < 0.01). The maternal CAR was also significantly attenuated in later compared to earlier gestation (p = 0.003). In the CG, there were no significant differences in psychophysiological stress responses and in the CAR across the two assessments. Among pregnant women there is a progressive attenuation of psychophysiological stress responses with advancing gestation. This attenuation is unlikely to be attributable to habituation. Individual differences in the degree of attenuation of stress responses over gestation may represent a novel marker of stress susceptibility in human pregnancy.

Fetal responses to induced maternal relaxation during pregnancy

Fetal responses to induced maternal relaxation during the 32nd week of pregnancy were recorded in 100 maternal–fetal pairs using a digitized data collection system. The 18-min guided imagery relaxation manipulation generated significant changes in maternal heart rate, skin conductance, respiration period, and respiratory sinus arrhythmia. Significant alterations in fetal neurobehavior were observed, including decreased fetal heart rate (FHR), increased FHR variability, suppression of fetal motor activity (FM), and increased FM–FHR coupling. Attribution of the two fetal cardiac responses to the guided imagery procedure itself, as opposed to simple rest or recumbency, is tempered by the observed pattern of response. Evaluation of correspondence between changes within individual maternal–fetal pairs revealed significant associations between maternal autonomic measures and fetal cardiac patterns, lower umbilical and uterine artery resistance and increased FHR variability, and declining salivary cortisol and FM activity. Potential mechanisms that may mediate the observed results are discussed.

The Effects of Alfentanil on Mother and Neonate during the Induction of General Anesthesia for a Cesarean Section

Background: During general anesthesia for a cesarean section, light depth of anesthesia frequently leads to maternal awareness and pain responses. The aim of this study was to evaluate the effects of alfentanil on the mother and neonate during a cesarean section. Methods: Forty four parturients undergoing general anesthesia for an elective cesarean section were enrolled in this study. General anesthesia was induced with propofol 2 mg/kg and succinylcholine 1.5 mg/kg after an intravenous injection of normal saline 0.02 ml/kg for the control group or alfentanil 10/kg for the alfentanil group. After tracheal intubation, anesthesia was maintained with (2 L/min)- (2 L/min)-isoflurane (0.5% end tidal). Mean blood pressure (MBP), heart rate, bispectral index (BIS) and maternal pain responses by an isolated forearm technique were measured every 1 min until delivery. Apgar scores of neonates were measured at 1 min and 5 min after delivery. Results: There were no differences between groups in the MBP, BIS or maternal pain responses. However heart rates were lower in the alfentanil group than in the control group (P = 0.017). Conclusions: The supplemental administration of alfentanil 10/kg can attenuate the changes in maternal heart rate during general anesthesia for a cesarean section without neonatal Apgar score decline.

Maternal stress responses and anxiety during pregnancy: Effects on fetal heart rate

This study examined the effect of an acute maternal stress response and anxiety on fetal heart rate. Seventeen healthy, 3rd-trimester pregnant women (mean age = 26 ± 6 years) were instrumented for continuous electrocardiography, blood pressure (BP), respiration, and fetal heart rate (HR). Subjects completed the state anxiety subscale of the State Trait Personality Inventory (STPI), then rested quietly in a semirecumbent position for a 5-min baseline period, followed by either a 5-min arithmetic or Stroop color–word task. Over the entire 5-min stress period and when averaged across all subjects, the stressors led to significant increases in maternal systolic BP and respiratory rate but changes in maternal HR, diastolic BP, and fetal HR were not significant. However, when subjects were dichotomized into groups that had above or below average anxiety scores [ANX(+) and ANX(−)], both groups had similar respiration rate increases to the stressors, but the BP and fetal heart rate (FHR) responses were significantly different. Women in the ANX(−) group had significantly greater BP responses compared to women in the ANX(+) group whereas the fetuses of ANX(+) women showed significant HR increases and the fetuses of ANX(−) women exhibited nonsignificant decreases. These findings suggest that women's acute emotional reactivity during pregnancy can influence fetal HR patterns and that a stress-induced increase in maternal BP is not the primary signal by which a women's stress response is transduced to her fetus. The results are consistent with the hypothesis that maternal psychological variables may shape the neurobehavioral development of the fetus. © 2000 John Wiley & Sons, Inc. Dev Psychobiol 36: 67–77, 2000

Maternal stress responses and anxiety during pregnancy: Effects on fetal heart rate

This study examined the effect of an acute maternal stress response and anxiety on fetal heart rate. Seventeen healthy, 3rd-trimester pregnant women (mean age = 26 +/- 6 years) were instrumented for continuous electrocardiography, blood pressure (BP), respiration, and fetal heart rate (HR). Subjects completed the state anxiety subscale of the State Trait Personality Inventory (STPI), then rested quietly in a semirecumbent position for a 5-min baseline period, followed by either a 5-min arithmetic or Stroop color-word task. Over the entire 5-min stress period and when averaged across all subjects, the stressors led to significant increases in maternal systolic BP and respiratory rate but changes in maternal HR, diastolic BP, and fetal HR were not significant. However, when subjects were dichotomized into groups that had above or below average anxiety scores [ANX(+) and ANX(-)], both groups had similar respiration rate increases to the stressors, but the BP and fetal heart rate (FHR) responses were significantly different. Women in the ANX(-) group had significantly greater BP responses compared to women in the ANX(+) group whereas the fetuses of ANX(+) women showed significant HR increases and the fetuses of ANX(-) women exhibited nonsignificant decreases. These findings suggest that women's acute emotional reactivity during pregnancy can influence fetal HR patterns and that a stress-induced increase in maternal BP is not the primary signal by which a women's stress response is transduced to her fetus. The results are consistent with the hypothesis that maternal psychological variables may shape the neurobehavioral development of the fetus.

Epidural block for obstetrics: Comparison of bolus injection of local anesthetic with gravity flow technique

Study Objective: To test the hypothesis that slow administration of local anesthetic into the epidural space by gravity flow reduces the incidence of signs and symptoms of unintended injection. Design: Prospective, randomized study. Setting: Teaching hospital. Patients: 600 ASA physical status I and II parturients scheduled for labor and delivery or elective cesarean section. Interventions: After identification of the epidural space with pulsations of an air-fluid column, parturients for vaginal delivery (n = 380) were randomized to receive a test dose of 3 ml 3% 2-chloroprocaine with epinephrine 20 μg, two doses of 7 ml bupivacaine 0.03 % with sufentanil 1 μg/ml and epinephrine 2 μg/ml by either gravity flow (Group 1) given over 30 seconds or by bolus injection (Group 2) given over 5 seconds through the epidural needle; parturients for Cesarean delivery (n = 220) were randomized to receive a test dose and two doses of 6 ml lidocaine 2 % with sufentanil 1 μg/ml and epinephrine 2 μg/ml by either gravity flow or by bolus injection through the epidural needle. Changes in maternal heart rate (HR) and blood pressure, signs of intravascular injection, and adverse effects of epidural bupivacaine-sufentanil were recorded after each dose. Measurements and Main Results: Gravity flow administration (Group 1) was associated with a smaller increase in mean maternal HR ( p < 0.001), less hypotension ( p < 0.01), sedation ( p < 0.01), nausea ( p = 0.01), and segmental spread ( p < 0.0001) than were corresponding doses given by traditional bolus injection (Group 1) for vaginal or Cesarean deliveries. The incidence of systemic toxicity was zero of 300 (0%) with gravity flow and 4 of 300 (1.3%) by bolus injection, p = 0.12, Fisher's exact test. No patient in either group had an accidental intrathecal injection. Conclusion: Gravity flow administration of local anesthetic-opioid solution during epidural block for obstetrics was associated with fewer signs of systemic drug absorption and cardiovascular perturbations than was the traditional bolus injection. This study supports the current opinion that slow administration of local anesthetic during epidural black contributes to fewer adverse events.

Effect of Crystalloid and Colloid Preloading on Uteroplacental and Maternal Haemodynamic State During Spinal Anaesthesia for Caesarean Section

We have studied the effects of crystalloid 1 litre (lactated Ringer's) or colloid 0.5 litre (hydroxyethyl starch) preloading in 26 healthy parturients undergoing elective Caesarean section under spinal anaesthesia. Maternal placental uterine artery circulation was measured using a pulsed colour Doppler technique with simultaneous measurement of maternal haemodynamics. A high incidence of maternal hypotension was observed during spinal anaesthesia in the crystalloid group (62%) but the incidence was lower in the colloid group (38%). Central venous pressure was increased significantly in both groups after preload but decreased shortly after induction of spinal anaesthesia to baseline values. The mean pulsatility index (PI) in the uterine arteries did not change during preload or spinal block. A surprising finding was the widespread variation and some high values for the uterine artery PI after spinal anaesthesia. These individual increases in PI were transient and always returned to baseline values within 2 min. These results suggest that preloading with either solution is ineffective in preventing maternal hypotension and that changes in maternal heart rate, systolic arterial pressure and central venous pressure during spinal anaesthesia were not associated with rapid individual increases in uteroplacental vascular resistance. These changes seemed not to have any major effect, however, on the clinical condition of the newborn, as assessed by Apgar scores and umbilical artery pH values.