Prophylactic Ephedrine and Combined Spinal Epidural

Side effects from epidural analgesia in laboring women and risk of cesarean delivery

BACKGROUND

Epidural analgesia may cause maternal hypotension and changes in the fetal heart rate. The implications of such side effects on the course of labor and delivery are incompletely understood.

OBJECTIVE

This study aimed to assess whether the occurrence of maternal or fetal side effects associated with labor epidural analgesia increased the risk for cesarean delivery.

STUDY DESIGN

This was a cohort study of all women who underwent epidural analgesia during labor for the period October 1, 2020 to December 31, 2020. Excluded were cases of multiples, fetal death, noncephalic presentation, and gestational age at birth <37.0 weeks. Maternal vital signs and fetal heart rate tracings for the 1 hour before and 1 hour after epidural analgesia was administered were reviewed. The occurrence of maternal hypotension, defined as a continuous variable and dichotomized into a decrease in maternal systolic blood pressure to <90 mm Hg or a drop in systolic blood pressure by >20% below the last value before epidural analgesia was administered, was related to changes in the fetal heart rate category. The principal outcome was cesarean delivery rate; binary logistic regression analysis was used to control for confounders, and mediation model analysis was used to quantify the extent to which significant variables participated in the causation pathway to cesarean delivery (SPSS version 28 was used for the analyses).

RESULTS

A total of 439 women met the study criteria. Significant adverse reactions owing to epidural occurred in 184 of 439 women (41.9%) and included severe maternal hypotension in 159 of 439 participants (36.2%) and worsening fetal heart rate category in 50 of 439 participants (11.4%). The logistic regression analysis revealed that cervical dilation at epidural (P=.03), the duration of labor after epidural (P<.001), and worsening fetal heart rate category within 60 minutes of epidural administration (P=.01) were independently associated with recourse to cesarean delivery. The mediation analysis showed that both cervical dilatation at epidural administration and worsening fetal heart rate category had significant direct and indirect effects in the pathway to cesarean delivery.

CONCLUSION

Worsening fetal heart rate category related to labor epidural independently increased the risk for cesarean delivery.

Treatment of spinal anaesthesia-induced hypotension with cafedrine/theodrenaline versus ephedrine during caesarean section: Results from HYPOTENS, a national, multicentre, prospective, noninterventional study

BACKGROUND

In Germany, hypotension induced by spinal anaesthesia is commonly treated with a combination of cafedrine hydrochloride (C, 200 mg) and theodrenaline hydrochloride (T, 10 mg) in 2 ml. We compared the effectiveness of C/T with ephedrine.

OBJECTIVES

The primary objectives were to assess the speed of onset and the ability to restore blood pressure without an increase in heart rate. Secondary objectives were to evaluate maternal/foetal outcomes and the number of required additional boluses or other additional measures.

DESIGN

HYPOTENS was a national, multicentre, prospective, open-label, two-armed, noninterventional study comparing C/T with ephedrine in two prospectively defined cohorts. This study relates to the cohort of patients receiving spinal anaesthesia for caesarean section.

SETTING

German hospitals using either C/T or ephedrine in their routine clinical practice.

PATIENTS

Women aged at least 18 years receiving spinal anaesthesia for caesarean section.

INTERVENTIONS

Bolus administration of C/T or ephedrine at the discretion of the attending anaesthesiologist.

MAIN OUTCOME MEASURES

Endpoints within 15 min after initial administration of C/T or ephedrine were area under the curve between the observed SBP and the minimum target SBP; and incidence of newly occurring heart rate of at least 100 beats min-1.

RESULTS

Although effective blood pressure stabilisation was achieved with both treatments, this effect was faster and more pronounced with C/T (P < 0.0001). The incidence of tachycardia and changes in heart rate were higher with ephedrine (P < 0.01). Fewer additional boluses (P < 0.01) were required with C/T. Although favourable neonatal outcomes were reported in both groups, base deficit and lactate values were greater with ephedrine (P < 0.01). Physician satisfaction was higher with C/T.

CONCLUSIONS

After C/T, tachycardia was not a problem, providing an advantage over ephedrine. Fewer additional boluses were required with C/T, suggesting greater effectiveness. An increased base deficit with ephedrine suggests reduced oxygen supply or increased demands in foetal circulation.

TRIALS REGISTRATION

Clinicaltrials.gov: NCT02893241, German Clinical Trials Register: DRKS00010740.

The efficacy of intramuscular ephedrine in preventing hemodynamic perturbations in patients with spinal anesthesia and dexmedetomidine sedation

Dexmedetomidine is used for sedation during spinal anesthesia. The sympatholytic effect of dexmedetomidine may exacerbate hypotension and bradycardia with spinal anesthesia. This study investigated the effects of prophylactic intramuscular injection of ephedrine in preventing hypotension and bradycardia occurring through combined use of spinal anesthesia and dexmedetomidine. One hundred sixteen patients scheduled for lower extremity orthopedic surgery were randomized into two groups receiving either ephedrine 20 mg intramuscularly or equivalent amount of 0.9% NaCl, both with dexmedetomidine and spinal anesthesia. The primary endpoint was the incidence of hemodynamic perturbations (hypotension or bradycardia event). The secondary endpoint was a rescue doses of ephedrine and atropine. The incidence of hemodynamic perturbations was significantly lower in the ephedrine group compared with to the saline group (26.3% versus 55.9%, p = 0.001). The rescue doses of atropine (0.09 ± 0.21 versus 0.28 ± 0.41, p = 0.001) and ephedrine (1.04 ± 2.89 versus 2.03 ± 3.25, p = 0.007) were also significantly lower in the ephedrine group. There was no differences in number of patients with hypertensive (7.0% versus 11.9%, p = 0.375) or tachycardia (1.8% versus 3.4% p = 0.581) episodes. The use of ephedrine intramuscular injections may be a safe and efficacious option in preventing hemodynamic perturbations in patients who received spinal anesthesia and sedation using dexmedetomidine.

Prophylactic intravenous ephedrine to minimize fetal bradycardia after combined spinal-epidural labour analgesia: a randomized controlled study

BACKGROUND

The combined spinal-epidural (CSE) technique for relief of labour pain offers both rapid onset and superior first-stage analgesia. Nevertheless, the known increased risk for early profound fetal bradycardia (EPFB) following CSE continues to be a concern that often limits its use. The purpose of this study was to determine if giving prophylactic intravenous ephedrine at the time of CSE administration would reduce EPFB.

METHODS

We conducted this clinical trial at a large community hospital and enrolled healthy patients requesting epidural analgesia for labour. Patients were randomly assigned to receive either normal saline placebo or ephedrine 10 mg iv at the time of CSE. The primary outcome of EPFB (defined as bradycardia < 90 beats·min(-1) for > two minutes and occurring within the first 30 min after CSE) was compared between groups. The secondary outcomes included the incidence of urgent cesarean delivery, the requirement for additional doses of ephedrine, maternal blood pressure, uterine hypertonus and tachysystole, and abnormal fetal heart rate (FHR) patterns before and after CSE.

RESULTS

There were 299 women randomized to the ephedrine (EPH) group and 297 randomized to the normal saline placebo (NS) group. There was no difference between groups in the incidence of EPFB (2.7% EPH group vs 4.7% NS group; relative risk, 0.57; 95% confidence interval, 0.24 to 1.33; P = 0.184). There was also no difference between groups in the incidence of urgent cesarean delivery, uterine hypertonus, uterine tachysystole, and abnormal FHR patterns.

CONCLUSIONS

We conclude that prophylactic intravenous ephedrine administration at the time of CSE during labour was ineffective at reducing the risk for EPFB associated with CSE. Nevertheless, a lower than expected rate of EPFB resulted in the trial being underpowered. This trial was registered at ClinicalTrials.gov, identifier: NCT02062801.

Open access intrapartum CTG database

Background

Cardiotocography (CTG) is a monitoring of fetal heart rate and uterine contractions. Since 1960 it is routinely used by obstetricians to assess fetal well-being. Many attempts to introduce methods of automatic signal processing and evaluation have appeared during the last 20 years, however still no significant progress similar to that in the domain of adult heart rate variability, where open access databases are available (e.g. MIT-BIH), is visible. Based on a thorough review of the relevant publications, presented in this paper, the shortcomings of the current state are obvious. A lack of common ground for clinicians and technicians in the field hinders clinically usable progress. Our open access database of digital intrapartum cardiotocographic recordings aims to change that.

Description

The intrapartum CTG database consists in total of 552 intrapartum recordings, which were acquired between April 2010 and August 2012 at the obstetrics ward of the University Hospital in Brno, Czech Republic. All recordings were stored in electronic form in the OB TraceVue®;system. The recordings were selected from 9164 intrapartum recordings with clinical as well as technical considerations in mind. All recordings are at most 90 minutes long and start a maximum of 90 minutes before delivery. The time relation of CTG to delivery is known as well as the length of the second stage of labor which does not exceed 30 minutes. The majority of recordings (all but 46 cesarean sections) is – on purpose – from vaginal deliveries. All recordings have available biochemical markers as well as some more general clinical features. Full description of the database and reasoning behind selection of the parameters is presented in the paper.

Conclusion

A new open-access CTG database is introduced which should give the research community common ground for comparison of results on reasonably large database. We anticipate that after reading the paper, the reader will understand the context of the field from clinical and technical perspectives which will enable him/her to use the database and also understand its limitations.

Maternal pulse pressure at admission is a risk factor for fetal heart rate changes after initial dosing of a labor epidural: a retrospective cohort study

OBJECTIVE

To examine low maternal admission pulse pressure (PP) as a risk factor for new onset postepidural fetal heart rate (FHR) abnormalities.

STUDY DESIGN

Retrospective cohort study of nulliparous, singleton, vertex-presenting women admitted to labor and delivery after 37 0/7 weeks that received an epidural during labor. Women with a low admission PP were compared with those with a normal admission PP. The primary outcome was new onset FHR abnormalities defined as recurrent late or prolonged FHR decelerations in the first hour after initial dosing of a labor epidural.

RESULTS

New onset FHR abnormalities, defined as recurrent late decelerations and/or prolonged decelerations, occurred in 6% of subjects in the normal PP cohort compared with 27% in the low PP cohort (odds ratio, 5.6; 95% confidence interval, 2.1-14.3; P < .001). A multivariate logistic regression analysis generated an adjusted odds ratio of 28.9 (95% confidence interval, 3.7-221.4; P < .001).

CONCLUSION

New onset FHR abnormalities after initial labor epidural dosing occur more frequently in women with a low admission PP than those with a normal admission pulse. Admission PP appears to be a novel predictor of new onset postepidural FHR abnormalities.

Management of foetal asphyxia by intrauterine foetal resuscitation

Management of foetal distress is a subject of gynaecological interest, but an anaesthesiologist should know about resuscitation, because he should be able to treat the patient, whenever he is directly involved in managing the parturient patient during labour analgesia and before an emergency operative delivery. Progressive asphyxia is known as foetal distress; the foetus does not breathe directly from the atmosphere, but depends on maternal circulation for its oxygen requirement. The oxygen delivery to the foetus depends on the placental (maternal side), placental transfer and foetal circulation. Oxygen transport to the foetus is reduced physiologically during uterine contractions in labour. Significant impairment of oxygen transport to the foetus, either temporary or permanent may cause foetal distress, resulting in progressive hypoxia and acidosis. Intrauterine foetal resuscitation comprises of applying measures to a mother in active labour, with the intention of improving oxygen delivery to the distressed foetus to the base line, if the placenta is functioning normally. These measures include left lateral recumbent position, high flow oxygen administration, tocolysis to reduce uterine contractions, rapid intravenous fluid administration, vasopressors for correction of maternal hypotension and amnioinfusion for improving uterine blood flow. Intrauterine Foetal Resuscitation measures are easy to perform and do not require extensive resources, but the results are encouraging in improving the foetal well-being. The anaesthesiologist plays a major role in the application of intrauterine foetal resuscitation measures.

Vasopressor choice for hypotension in elective Cesarean section: ephedrine or phenylephrine?

INTRODUCTION

Hypotensive episodes are a common complication of spinal anesthesia during Cesarean section. The purpose of this study was to compare the effectiveness and the side effects of vasopressors, ephedrine and phenylephrine, administered for hypotension during elective Cesarean section under spinal anesthesia.

MATERIAL AND METHODS

The study consisted of 100 selected ASA I/II females scheduled for elective Cesarean section under spinal anesthesia. Each patient was randomly assigned to one of the two double-blind study groups. Group E received 1 ml ephedrine (5 mg/ml) with normal saline if hypotension was present (n=50). Group P received 1 ml phenylephrine (100 µg/ml) with normal saline if hypotension developed (n=50). Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) were compared within and between groups to basal levels at time increments of 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, and 60 min from start of surgery. Incidence of side effects and neonatal outcomes were studied between groups.

RESULTS

All patients required vasopressor therapy for hypotension. Administration of phenylephrine was associated with significant drop in HR. Changes in SBP, DBP, and MAP were similar in both groups for most observed times. The incidences of nausea/vomiting and tachycardia were significantly higher in the ephedrine group.

CONCLUSIONS

Phenylephrine and ephedrine are acceptable choices to combat maternal hypotension related to spinal anesthesia in elective Cesarean section. Complications of intra-operative nausea and vomiting, tachycardia and bradycardia should be considered when choosing a vasopressor, suggesting phenylephrine may be more appropriate when considering maternal well-being.

Pathophysiology, management, and outcomes of fetal hemodynamic instability during prenatal cardiac intervention

Prenatal cardiac intervention (PCI) may favorably alter the in utero course of some congenital heart defects. In our preliminary experience with PCI, fetal hemodynamic instability (FHI) characterized by bradycardia and ventricular dysfunction was common. This study evaluated the pathophysiology, management, and short-term outcomes of FHI during PCI for aortic stenosis with evolving hypoplastic left heart syndrome (HLHS), HLHS with restrictive atrial septum, pulmonary atresia with intact ventricular septum, and hydrops due to structural heart disease. From 2000 to 2006, 83 fetuses underwent PCI, with ventricular access in 63, atrial access in 17, and both in three. FHI occurred in 37 fetuses (45%). FHI was associated with transventricular PCI (all but one case of FHI; p < 0.001) and large hemopericardium (n=9; p=0.07). Prolonged FHI was associated with severe ventricular distortion during ventricular puncture (p = 0.06). FHI was treated with resuscitation medications in 31 of 37 fetuses and resolved in all 37. Five fetuses died within 1 d of PCI: four had FHI and one had a massive hemopericardium. FHI is common and clinically important during transventricular PCI and may be caused by a ventricular reflex or reduced cardiac output from cardiac distortion during ventricular puncture. Hemopericardium may be causative in a subset of fetuses.