Biomedical subjects

S Alahuhta

Publications and source records attributed to S Alahuhta.

49 records · Page 3Linked to original sources

PubMed1995

The effects of epidural ropivacaine and bupivacaine for cesarean section on uteroplacental and fetal circulation.

BACKGROUND: Ropivacaine is a new long-acting amide local anesthetic that has been shown in animal studies to have less dysrhythmogenic and cardiotoxic potential than bupivacaine. The intravenous administration of ropivacaine has not been associated with any detrimental effects on uterine blood flow in pregnant ewes. The purpose of this randomized, double-blind study was to examine the effects of epidural ropivacaine for cesarean section on blood flow velocity waveforms in uteroplacental and fetal arteries with color Doppler ultrasound and to assess whether the block modified fetal myocardial function. METHODS: Healthy parturient women with singleton, uncomplicated pregnancies at term received 115-140 mg 0.5% ropivacaine (n = 11) or 0.5% bupivacaine (n = 10) in incremental epidural doses. The first ultrasound measurement was performed before injection of the study drug. Pulsatility indexes (PI) were derived for the blood flow velocity waveforms of the maternal placental and nonplacental uterine arteries; the placental arcuate artery; and the fetal umbilical, middle cerebral, and renal arteries. The fetal heart then was examined by echocardiography. The PI of the maternal uterine arteries and the fetal umbilical artery were measured 5 min after the injection of the local anesthetic. When sensory analgesia had reached the T6-T4 level, the ultrasound measurement was repeated with the same methods and targets as in the baseline measurement. RESULTS: Both drugs provided adequate surgical anesthesia for cesarean section. In the bupivacaine group, the PI values for the maternal placental and nonplacental uterine arteries increased significantly 5 min after the main dose (P = 0.01, P = 0.002) and when sensory analgesia had reached the T6-T4 level (P = 0.004, P = 0.01) as compared with the baseline measurement. Simultaneously, the PI in the fetal middle cerebral artery decreased significantly (P = 0.02). The PI for the maternal uterine artery increased significantly (P = 0.01) after ropivacaine administration but only on the nonplacental side and not until sensory analgesia had reached the T6-T4 level. No effect on the Doppler indexes obtained from the umbilical artery was observed in either group. There were no significant differences relative to baseline values in any fetal myocardial measurement or in any ultrasound measurement between the groups. Neither drug had any detrimental effect on Apgar scores or umbilical cord acid-base status. None of the neonates' conditions was markedly depressed according to neurobehavioral testing. CONCLUSIONS: Within this small study, epidural 0.5% ropivacaine for cesarean section did not compromise the utero-placental circulation in healthy parturient women with uncomplicated pregnancies. It provided surgical anesthesia that was equally effective as that provided by 0.5% bupivacaine.

Adult↗

PubMed1994

Uteroplacental haemodynamics during spinal anaesthesia for caesarean section with two types of uterine displacement.

The effects of two types of uterine displacement, on uterine and umbilical artery blood flow waveforms were investigated in 22 healthy parturients undergoing elective caesarean section. Displacement was accomplished with either a wedge under the right hip or a mechanical displacer plus 5 degrees left lateral tilt of the operating table. The first 14 patients were assigned randomly into one of the two displacement methods and the left (underlying) uterine and umbilical artery blood flow waveforms were recorded. In a further 8 patients the displacer was used and flow velocity waveforms for both the right and left uterine arteries and the umbilical artery were recorded. Arterial resistance was expressed in terms of the pulsatility index (PI). There were no significant changes in Doppler velocimetry recordings after preloading in either group, but blood flow velocity waveform indices for the underlying left uterine artery increased significantly (P < 0.001) following spinal anaesthesia when the mechanical device was used. This finding indicates increased vascular resistance in the left uterine artery and is probably due to mechanical compression. A wedge as a method for displacing the gravid uterus seems preferable since its use had no effect on the blood flow indices. The unaltered umbilical artery index values in the groups suggest a great tolerance of minor changes in maternal uterine circulation on the part of the fetus.

Journal Article↗

PubMed1994

Uteroplacental and fetal haemodynamics and cardiac function of the fetus and newborn after crystalloid and colloid preloading for extradural caesarean section anaesthesia.

We have studied the effects of randomized preloading with either a crystalloid (lactated Ringer's) 15 ml kg-1 or colloid (hydroxyethyl starch) 7.5 ml kg-1 solution in 20 parturients undergoing elective Caesarean section under extradural anaesthesia, on blood flow in maternal placental and non-placental uterine and placental arcuate arteries and in fetal umbilical, renal and middle cerebral arteries, using a pulsed colour Doppler technique. Simultaneously, fetal and neonatal myocardial function were investigated by pulsed Doppler and M-mode echocardiography. We found no changes in maternal or fetal blood velocity waveform indices after crystalloid preloading, but the pulsatility index of the maternal non-placental uterine artery increased significantly after colloid preloading. Fetal heart rate decreased after preloading with crystalloid solution. There were no differences in fetal or neonatal myocardial function between the groups, and the outcome of the newborn infants were uneventful in all cases. These results suggest that preloading with either a crystalloid or colloid solution may lead to different uterine and fetal haemodynamics but these solutions had only minimal effects on fetal and neonatal myocardial performance and no effect on the clinical condition of newborns in uncomplicated pregnancies.

Adult↗

PubMed1994

Pregnancy after cardiac surgery in patients with secondary pulmonary hypertension due to a ventricular septal defect.

Pulmonary hypertension is defined as pulmonary artery pressure greater than 30/15 mmHg. The etiologies of pulmonary hypertension can be divided into primary and secondary ones. The causes of the latter include long-lasting left-to-right shunts (congenital cardiac defects e.g. ventricular septal defect), pulmonary thromboembolism and severe pulmonary disease (1). Women with pulmonary hypertension often tolerate the physiological changes of pregnancy poorly. We describe the intrapartum management and outcome of two patients who had undergone successful surgical closure of a ventricular septal defect several years earlier. They both had developed pulmonary arterial hypertension preoperatively but had an uneventful recovery and were clinically asymptomatic before pregnancy.

Adult↗

PubMed1993

Uteroplacental and fetal circulation during extradural bupivacaine-adrenaline and bupivacaine for caesarean section in hypertensive pregnancies with chronic fetal asphyxia.

We have studied the effects of an extradural block during Caesarean section using either bupivacaine plain or with adrenaline 85-100 micrograms on blood velocity waveforms of maternal uterine and placental arcuate arteries and fetal umbilical, renal and middle cerebral arteries, in 20 hypertensive parturients with chronic fetal asphyxia. Fetal myocardial function was investigated at the same time by M-mode echocardiography. Extradural anaesthesia resulted in a significant decrease in maternal mean systolic and diastolic arterial pressures in both groups, but this was more marked after plain bupivacaine. There were no significant differences in any of the Doppler recordings relative to baseline values after plain bupivacaine, but after bupivacaine with adrenaline there were significantly increased blood flow velocity indices for the maternal uterine and placental arcuate arteries and significantly decreased indices in the fetal renal and middle cerebral arteries. Neonatal outcome as evaluated by Apgar scores and acid-base values in the umbilical cord were similar in the two groups. The results suggest that adrenaline added to the solution of bupivacaine increased vascular resistance in the uteroplacental circulation, indicating impaired blood flow.

Anesthesia, Epidural↗

PubMed1993

Epidural sufentanil and bupivacaine for labor analgesia and Doppler velocimetry of the umbilical and uterine arteries.

BACKGROUND: The pain of parturition is associated with major physiologic alterations mediated by neurohumoral factors and increased activation of the sympathetic nervous system. Epidural local anesthetics abolish or alleviate many of the pain-mediated responses by reducing maternal catecholamine levels, inducing sympathectomy and consequent vasodilatation. The hormone response to surgical stress is not attenuated after epidural opioids as efficiently as after local anesthetics. Opioid receptors may modulate sympathetic outflow at a spinal level. This study was performed to compare the effects of epidural sufentanil and bupivacaine on the uterine and placental circulation. METHODS: Utilizing a prospective randomized, double-blind study design, 30 healthy women at term were examined employing a color Doppler technique to assess and compare the effects of analgesia using sufentanil or bupivacaine epidurally during the first stage of labor on blood flow velocity waveforms in the uterine and umbilical arteries. RESULTS: Effective analgesia was provided by both drugs, bupivacaine and sufentanil. Uterine and umbilical blood velocity waveform indices did not change significantly. There was, however, a significantly greater incidence of fetuses with changes in heart rate tracings in the sufentanil group, decreased variability being the most frequent. Maternal side effects attributable to sufentanil were common but mild. No patient became hypotensive in either group. CONCLUSIONS: Epidural sufentanil and bupivacaine provide effective analgesia with acceptable side effects during the first stage of labor in healthy parturients. Neither drug had any detrimental effects on blood flow indexes reflecting peripheral vascular resistance in the umbilical and uterine arteries in healthy parturients.

Adult↗

PubMed1992

Ephedrine and phenylephrine for avoiding maternal hypotension due to spinal anaesthesia for caesarean section. Effects on uteroplacental and fetal haemodynamics.

The effects of i.v. vasopressors on Doppler velocimetry of the maternal uterine and placental arcuate arteries and the fetal umbilical, renal and middle cerebral arteries were studied during spinal anaesthesia in 19 healthy parturients undergoing elective caesarean section. Fetal myocardial function was investigated at the same time by M-mode echocardiography. The patients were randomized into two groups, to be given either ephedrine or phenylephrine as a prophylactic infusion supplemented with minor boluses if systolic arterial pressure decreased by more than 10 mmHg from the control value. Both the vasopressors restored maternal arterial pressure effectively. The ephedrine group showed no significant differences in any of the Doppler velocimetry recordings relative to the baseline values, but during the phenylephrine infusion the blood flow velocity waveform indices for the uterine and placental arcuate arteries increased significantly and vascular resistance decreased significantly in the fetal renal arteries. Healthy fetuses seem to tolerate these changes in uteroplacental circulation well, however, since the Apgar scores for the newborns and the acid-base values in the umbilical cord were within the normal range in both groups. The results suggest that some caution is required when selecting the specific vasopressor agent, the dosage and the mode of administration for the treatment of maternal hypotension secondary to spinal anaesthesia for caesarean section.

Journal Article↗

PubMed1991

The effects of ephedrine and etilefrine on uterine and fetal blood flow and on fetal myocardial function during spinal anaesthesia for caesarean section.

The effects of two vasopressors, ephedrine and etilefrine, on blood flow in maternal uterine, fetal umbilical, middle cerebral and renal arteries and on fetal myocardial function were studied by colour Doppler and M-mode echocardiography techniques during spinal anaesthesia for caesarean section. There were 7 healthy pregnant women in each treatment group. The vascular resistance of maternal uterine arteries increased significantly after both of the vasopressors while the vascular resistance of the umbilical artery remained unchanged. Ephedrine decreased the blood velocity waveform indices in the fetal middle cerebral and renal arteries, increased fetal right ventricular contractility and decreased left ventricular inner end-diastolic dimension. Fetal heart rate was unchanged. Etilefrine caused no detectable changes in fetal haemodynamics or in fetal myocardial function. These findings demonstrate that vasopressors administered for the treatment of minor maternal arterial pressure fall produce vasoconstriction in the uterine circulation during spinal anaesthesia, yet healthy fetuses seem to tolerate these haemodynamic alterations well. On the other hand, ephedrine caused changes in fetal myocardial function and in the vascular resistance of fetal middle cerebral and renal arteries, which demonstrates the potential modifying effect of vasoactive drug given to the mother on fetal haemodynamics.

Journal Article↗

PubMed1991

Uteroplacental and fetal haemodynamics during extradural anaesthesia for caesarean section.

We have studied the effects of extradural anaesthesia with bupivacaine (plain) in eight healthy parturients undergoing elective Caesarean section, on blood flow in maternal uterine and placental arcuate arteries and in fetal umbilical, renal and middle cerebral arteries, using a colour Doppler technique. Simultaneously, fetal myocardial function was investigated by M-mode echocardiography. Maternal and fetal blood velocity waveform indices did not change significantly. We found no changes in fetal myocardial function with extradural anaesthesia, except for an increase in the right ventricular inner end-diastolic dimensions. These results suggest that extradural anaesthesia has no detrimental effects on uteroplacental and fetal circulations in the uncomplicated pregnancy when maternal hypotension is avoided with rapid prehydration.

Anesthesia, Epidural↗

PubMed1991

Effects of extradural bupivacaine with adrenaline for caesarean section on uteroplacental and fetal circulation.

We have studied the effects of an extradural block using bupivacaine with adrenaline 90-100 micrograms on blood flow in the maternal uterine and placental arcuate arteries and the fetal umbilical, renal and middle cerebral arteries, using a colour Doppler technique in eight healthy parturients undergoing elective Caesarean section. Fetal myocardial function was investigated simultaneously by M-mode echocardiography. Maternal heart rate increased and diastolic arterial pressure decreased after extradural administration of bupivacaine with adrenaline. The latter effect was relieved by increasing the infusion rate in every case and none of the patients required vasopressors. There were no significant differences in maternal or fetal blood velocity waveforms, and no significant changes were found in any of the fetal myocardial measurements relative to control values. These observations suggest that extradural anaesthesia using bupivacaine with adrenaline does not have an adverse effect on vascular resistance in the uteroplacental or fetal circulations or on fetal myocardial function in normal pregnancy when bupivacaine-adrenaline is administered fractionally and maternal hypotension is prevented by rapid crystalloid volume loading.

Anesthesia, Epidural↗

PubMed1990

Does ephedrine influence newborn neurobehavioural responses and spectral EEG when used to prevent maternal hypotension during caesarean section?

The recovery of 16 infants born by elective caesarean section with spinal anaesthesia, in which either ephedrine or fluid load was used to prevent maternal hypotension, were studied using Scanlon's neurobehavioural tests and a computerized EEG. Neurobehavioural testing showed no differences between the ephedrine and the non-ephedrine groups of infants at ages of 3 h, 1 day, 2 days and 4-5 days, whereas the spectral EEG showed significant differences between the two groups during the first 2 h after delivery, which had disappeared 24 h later. It is suggested that small doses of ephedrine given to the mother i.v. to prevent hypotension during spinal anaesthesia have short-lived effects on the neonate's central nervous system, which will be detected in the spectral EEG, but not in neurobehavioural tests.

Adult↗

PubMed1990

Visceral pain during caesarean section under spinal and epidural anaesthesia with bupivacaine.

In a randomized study, the incidence of visceral pain was evaluated in 46 patients undergoing elective caesarean section under spinal or epidural anaesthesia with 0.5% bupivacaine. If the patient experienced pain during the operation, a standard visual analogue scale ranging from 0 to 10 was used to assess the degree of pain. Visceral pain occurred in 12/23 patients in the spinal group and in 13/23 patients in the epidural group. In neither group was a correlation found between the cephalad level of analgesia or the intensity of cutaneous analgesia in the sacral region, and the presence of visceral pain.

Abdominal Pain↗

PubMed1989

The effect of lumbar epidural analgesia on the neurobehavioural responses of newborn infants.

The effects of maternal lumbar epidural analgesia (Th10-L5) on the neonatal neurobehavioural response were studied at the ages of 3 h, 1 day, 2 days and 4-5 days. The subjects were healthy, full-term neonates, born vaginally to 15 mothers with lumbar epidural block and 19 mothers without analgesia. Those delivered with epidural analgesia scored significantly better on alertness at the age of 3 h, 2 days and 4-5 days than the control group. No other statistically significant differences were found between the groups. The formation of the two groups according to the mothers' desire for epidural analgesia may have contributed to differences in the process of labour, but with this reservation it may be suggested that lumbar epidural analgesia may enhance the infant's recovery from the stress of labour and vaginal delivery.

Analgesia, Epidural↗