Application of a fetal scalp electrode for continuous fetal heart rate monitoring during an ex utero intrapartum treatment

Fetal monitoring is required to avoid hypoxic injury during ex utero intrapartum treatment (EXIT). We performed a tracheostomy under EXIT in a case of suspected airway obstruction caused by a cervical teratoma. The scalp electrode was applied for continuous fetal heart rate monitoring. This device enabled us to promptly deal with fetal bradycardia caused by cord compression. We describe here the usefulness of the fetal scalp electrode for fetal monitoring under EXIT.     

Fetal heart rate monitoring during fetoscopic repair of open spinal neural tube defects: a single-centre observational cohort study

BackgroundDuring fetal surgery, the haemodynamic stability of the fetus depends on the haemodynamic stability of the mother. The primary objective of this study was to assess changes in fetal heart rate (FHR) throughout the different stages of surgery. The secondary objective was to assess potential changes in maternal physiological parameters and their association with FHR.MethodsThis was a single-center observational cohort study conducted between 2015 and 2019 in 26 women undergoing intra-uterine fetoscopic repair of open spina bifida. The primary outcome was FHR. Maternal physiologic parameters were measured at the beginning, during and after surgery. The linear mixed-effects model fitted by maximum likelihood was used to assess changes in each variable at specific times throughout the surgery, and the repeated measures correlation coefficient was used to study the association between FHR and maternal physiological parameters.ResultsOne (3.8%) case of fetal bradycardia (FHR <110 beats per minute) required the administration of intramuscular atropine. No other significant FHR changes were observed during surgery. Maternal oesophageal temperature (P <0.001), lactate levels (P=0.002), and mean arterial pressure (P=0.016) changed significantly during surgery, although none of these changes was clinically relevant. The FHR showed a significant association with maternal carbon dioxide tension (r=0.285, 95% CI 0.001 to 0.526) and maternal heart rate (r=0.302, 95% CI 0.025 to 0.535).ConclusionThe FHR remained stable during intra-uterine fetoscopic repair of open spina bifida. Maternal carbon dioxide tension and heart rate may have a mild influence on FHR.     

Diagnosis of an unsuspected maternal hemorrhage via fetal heart rate tracing

Early detection of placental abruption often relies on the observation of vaginal bleeding; however, overt bleeding does not always occur. We report the case of an unsuspected placental abruption diagnosis that was prompted by an internal fetal scalp electrode tracing. The presence of a "normal" fetal heart rate (FHR) of approximately 150 beats per minute with poor variability, which matched the maternal heart rate (MHR), suggested that the tracing was not of fetal origin. An urgent ultrasound examination revealed a fetal demise with a possible concealed abruption, proving that the scalp electrode tracing was actually maternal in origin. Though reports of transmission of MHR via a deceased fetus are not new, it is uncommon for MHR to mimic a normal, reassuring FHR. This report reinforces the need for anesthesiologists to be adept at interpreting and integrating FHR monitors with maternal monitors prior to initiation of epidural analgesia.     

Severe fetal bradycardia in a pregnant surgical patient despite normal oxygénation and blood pressure

PURPOSE: To report and discuss a case of fetal bradycardia in a parturient under anesthesia for cholecystectomy despite normal maternal oxygenation and arterial blood pressure. CLINICAL FEATURES: A 27-yr-old woman (gravida 2 para 1), with a fetus of 34 weeks gestation, received general anesthesia for cholecystectomy. After anesthesia induction and tracheal intubation, anesthesia was maintained with oxygen, sevoflurane and iv remifentanil infusion. While preparing for surgery, the fetal heart rate decreased within about half a minute to 70 beats x min(-1) and remained at that level. The maternal blood pressure, heart rate and oxygen saturation were normal. An emergency Cesarean delivery was performed. The infant had Apgar scores of 1 at one minute, 5 at five minutes, 7 at ten minutes and required resuscitation after birth. CONCLUSION: Ideally, women having non-obstetric surgery during the third trimester of pregnancy will have intraoperative fetal heart rate monitoring.     

Case of general anesthesia for subtotal thyroidectomy in a pregnant woman with 27th week gestation

We report a case of general anesthesia for subtotal thyroidectomy in a pregnant woman with 27th week gestation. A 33-year-old pregnant woman was diagnosed with thyroid carcinoma. We planned subtotal thyroidectomy at 27 weeks of gestation. We gave thiamylal, fentanyl and rocuronium for induction of anesthesia. Tracheal intubation was performed. Anesthesia was maintained with sevoflurane and fentanyl. Because of tachycardia, we tilted the operating table to displace the uterus to the left. We continued monitoring fetal heart rate during the operation. The fetal heart rate remained between 130 and 150 beats x min(-1). The operation was performed with no trouble. She gave birth to a baby at 37th week gestation. We should pay attention to maternal safety, fetal toxicity including teratogenecity, fetal asphyxia and pre-term labor. We could successfully manage her anesthesia using intraoperative fetal heart rate monitoring.     

Peri-operative management of percutaneous fetoscopic spina-bifida repair: a descriptive review of five cases from the United Kingdom,with focus on anaesthetic implications

We present a case-based review of the first five percutaneous fetoscopic in-utero spina bifida repair procedures undertaken in the UK. Our focus is on implications of anaesthesia and analgesia for the mother and fetus, provision of uterine relaxation and fetal immobilisation while providing conditions conducive to surgical access. Minimising risks for fetal acidosis, placental and fetal hypoperfusion, maternal and fetal sepsis and maternal fluid overload were the foremost priorities. We discuss optimisation strategies undertaken to ensure fetal and maternal well-being under anaesthesia, shortcomings in the current approach, and possible directions for improvement.     

A randomized prospective study of music therapy for reducing anxiety during cast room procedures

BACKGROUND: Cast room procedures, such as cast application and removal, pin removal, and suture removal can cause significant anxiety in young children. The use of music therapy in the cast room to decrease anxiety has not been previously reported. METHODS: We performed a randomized, prospective study of soft lullaby music compared with no music in 69 children 10 years or younger undergoing cast room procedures. Heart rates (beats per minute) were recorded in the waiting room and cast room using a pulse oximeter. RESULTS: A total of 28 children were randomized to music and 41 children to no music. The mean rise in heart rate between the waiting room and entering the cast room was -2.7 beats/min in the music group and 4.7 beats/min in the no music group (P = 0.001). The mean difference in heart rate between the waiting room and during the procedure was 15.3 beats/min in the music group and 22.5 beats/min in the no music group (P = 0.05). There were 7 patients in the no music group with heart rate increases of greater than 40 beats/min. No patient in the music group had an increase of this magnitude. CONCLUSIONS: Playing soft music in the cast room is a simple and inexpensive option for decreasing anxiety in young children during cast room procedures. LEVEL OF EVIDENCE: Randomized Clinical Trial, Level II.     

Transesophageal echocardiography in fetal sheep

Background: Cardiac procedures in exteriorized fetuses or assisted by fetoscopy require monitoring capabilities not attended by conventional maternal transabdominal echocardiography. Methods: We, therefore, assessed the potential of fetal transesophageal echocardiography (TEE) utilizing an intravascular ultrasound catheter (IVUC) for fetal cardiac monitoring. We inserted a 10-F-10-MHz IVUC into the esophagus in 12 exteriorized fetal sheep and by a fetoscopic approach in 4 fetal sheep. Cardiac events were observed. Heart rate, cardiac rhythm, patency of the foramen ovale and ductus arteriosus, and the width of the branch pulmonary arteries could be assessed in all fetuses. Ventricular contractility could be assessed only in fetuses weighing less than 2.5 kg. Larger fetuses did not allow adequate imaging of the apical portion of the ventricles because of limited tissue penetration of the IVUC. Fetal TEE permitted placing small guide wires in the cardiac atria and left ventricle. Short-lived premature beats following intracardiac manipulations of these wires could be observed by fetal TEE in all cases. Results: At autopsy, no complications from IVUC insertion were observed in the exteriorized fetuses. Fetoscopic placement of the IVUC resulted in minor perioral skin erosion in two nonexteriorized fetuses. Conclusions: In conclusion, fetal TEE can be achieved with minor fetal injury and may provide useful information during open and fetoscopic cardiac procedures. Further improvements in IVUC design will permit the application of this technique to monitor human fetal cardiac procedures.     

Halothane Anaesthesia and Suxamethonium I: The Significance of Preoperative Atropine Administration

Preoperative administration of atropine was evaluated during induction of halothane anaesthesia with two administrations of suxamethonium 1 mg/kg body weight, 5 min apart.
Sixty-eight healthy, adult patients were studied. They were divided into five groups according to dose and route of administration of atropine. EGG was continuously monitored. Serum potassium, pH, Paco₂, Pao₂ and standard bicarbonate were measured at appropriate intervals.
It was found that neither atropine 0.01 mg/kg body weight given intramuscularly 1 h before the anaesthesia nor atropine 0.01 mg/kg body weight given intravenously 5 min prior to induction protected against serious bradycardias (defined as heart rate below 20 beats per minute) following the second dose of suxamethonium.
No serious brady-arrhythmias were seen in patients given either a combination of intramuscular and intravenous atropine in the above-mentioned doses or in patients given atropine 0.015 mg/kg body weight intravenously 5 minutes prior to induction. However, a decrease in heart rate to around 40–50 beats per minute occurred in some of these patients. Furthermore, these large doses of atropine caused an increase in heart rate during induction to more than 120 beats per minute in about 50% of the patients and to more than 140 beats per minute in about 25% of the patients.
Our results suggest that preoperative administration of atropine does not protect against serious brady-arrhythmias following a second dose of suxamethonium, unless doses of atropine are used which cause tachycardia of considerable degree.     

The effect of maternal hypothermic cardiopulmonary bypass on fetal lamb temperature, hemodynamics, oxygenation, and acid-base balance

OBJECTIVE: To evaluate fetal-maternal temperature relationship and fetal cardiovascular and metabolic response during maternal hypothermic cardiopulmonary bypass in pregnant ewes. METHODS: Cardiopulmonary bypass was instituted in 9 pregnant ewes, reaching 2 different levels of maternal hypothermia: 24 degrees C to 20 degrees C (deep hypothermia) in group A (5 cases) and less than 20 degrees C (very deep hypothermia) in group B (4 cases). Hypothermic levels were maintained for 20 minutes, then the rewarming phase was started. Fetal and maternal temperature, blood pressure, heart rate, electrocardiogram, blood gases, and acid-base balance were evaluated at different levels of hypothermia and during recovery. RESULTS: Fetal survival was related to maternal hypothermia: all group A fetuses survived, while 2 of 4 fetuses of group B in which maternal temperature was lowered below 18 degrees C died in a very deep acidotic and hypoxic status. Maternal temperature was always lower than fetal temperature during cooling; during rewarming the gradient was inverted. The start of cardiopulmonary bypass and cooling was associated with transient fetal tachycardia and hypertension; then, both fetal heart rate and blood pressure progressively decreased. The reduction of fetal heart rate was of 7 beats per minute for each degree of fetal cooling. Deep maternal hypothermia was associated with fetal alkalosis and reduction of Po(2). Very deep hypothermia, in particular below 18 degrees C, caused irreversible fetal acidosis and hypoxia. CONCLUSIONS: Deep maternal hypothermic cardiopulmonary bypass was associated with reversible modifications in fetal cardiovascular parameters, blood gases, and acid-base balance and therefore with fetal survival. On the contrary, fetuses did not survive to a very deep hypothermia below 18 degrees C.     

Hemodynamic effects of various modes of cardiac pacing after operation for idiopathic hypertrophic subaortic stenosis

The hemodynamic effects of varying heart rate and pacing site were studied in 6 patients with idiopathic hypertrophic subaortic stenosis following operative relief of outflow obstruction. Ventricular pacing (117 beats per minute) resulted in a 26% decrease in cardiac output (p less than 0.02), a 54% increase in pulmonary capillary wedge pressure (p less than 0.03), and a 23% decrease in mean blood pressure (p less than 0.05), compared with normal sinus rhythm (88 beats per minute). Slow atrial pacing (112 beats per minute) did not significantly alter any hemodynamic variable compared with normal sinus rhythm. Rapid atrial pacing (143 beats per minute) produced a similar degree of hemodynamic impairment as ventricular pacing. This study demonstrates that ventricular pacing at heart rates commonly used clinically and rapid atrial rates result in a significant fall in cardiac output. Preservation of atrial systole at heart rates that allow adequate diastolic ventricular filling of a hypertrophied, noncompliant ventricle is stressed. In addition, atrial electrodes are useful to record atrial electrograms or induce rapid atrial stimulation to treat supraventricular tachyarrhythmias.     

Maternally administered esmolol decreases fetal as well as maternal heart rate

Fetal heart rate was monitored during the administration of esmolol 100 μg/kg/min to a 36-year-old, 29-week pregnant woman who was undergoing craniotomy for surgical treatment of six cerebral aneurysms. During stable general anesthesia, sodium nitroprusside was administered to induce moderate hypotension; at the same time, esmolol was infused to control maternal tachycardia. Within minutes after starting the esmolol infusion, maternal heart rate decreased from 100 beats/minute to 65 beatslminute, and fetal heart rate decreased from 160 beatslminute to 130 beatslminute. Upon termination of the infusion 3 hours later, both maternal and fetal heart rate returned to preinfusion values. No adverse effects of esmolol infusion were noted in the mother or fetus.     

Holter监护仪与多普勒胎心监测准确性的比较研究

目的比较Holter监护仪与多普勒行胎心监测的可靠性和准确性。方法随机选取孕34~41周的200例孕妇,同时采用Holter监护仪与多普勒进行胎心监测,计算并比较母儿心率混淆率。结果 Holter监护仪在全程及母体高运动周期时母儿心率混淆率分别为7.5%及4.5%,显著低于多普勒胎心监测(22.5%,19.5%),差异有统计学意义(均P0.01),两种监测的一致性均较弱(Kappa系数分别为0.324、0.236)。在母体低运动周期,两种监测的母儿心率混淆率差异无统计学意义(P0.05),一致性适中(Kappa系数为0.485)。结论 Holter监护仪较多普勒胎心监测能够降低母儿心率混淆率,有更高的可靠性和准确性。     

Fetal monitoring for anesthesiologists]

Several monitoring methods for the fetus are presented, the knowledge of which is appropriate for anesthesiologists active in the field of obstetrics. A distinction is made between external, indirect methods for monitoring when the amniotic sac is intact and internal, direct methods employed when the sac has ruptured. Particular emphasis is placed on cardiotocography (CTG), which is an obligatory method of routine monitoring during the late period of cervical dilatation and expulsion. It registers the reaction of fetal heart rate to parturition and labor, and represents a good indirect measure of both uteroplacental blood flow and fetal cardiac reserve. Criteria of evaluation for cardiotocograms are presented on the basis of guidelines elaborated by the Standard Committee on Cardiotocography (Chairman: Prof. Dr. H. Rüttgers). These enable the status of the fetus to be evaluated with differentiation. An inevitable sign of fetal well-being is a normal baseline with a rate between 120 and 160 beats/min, normal microfluctuation, and oscillations between 5 and 25/min with absent variable or late decelerations. Warning signs are restricted microfluctuation, elevated baseline, variable decelerations, and clinical passage of meconium. Suspicious signs are a baseline between 100-119 and 161-170 beats/min, respectively, decreased oscillation amplitude, and protracted decelerations over as much as 2 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical validation of bioreactance for the measurement of cardiac output in pregnancy

Maternal cardiac dysfunction is associated with pre-eclampsia, fetal growth restriction and haemodynamic instability during obstetric anaesthesia. There is growing interest in the use of non-invasive cardiac output monitoring to guide antihypertensive and fluid therapies in obstetrics. The aim of this study was to validate thoracic bioreactance using the NICOM® instrument against transthoracic echocardiography in pregnant women, and to assess the effects of maternal characteristics on the absolute difference of stroke volume, cardiac output and heart rate. We performed a prospective study involving women with singleton pregnancies in each trimester. We recruited 56 women who were between 11 and 14 weeks gestation, 57 between 20 and 23 weeks, and 53 between 35 and 37 weeks. Cardiac output was assessed repeatedly and simultaneously over 5 min in the left lateral position with NICOM and echocardiography. The performance of NICOM was assessed by calculating bias, 95% limits of agreement and mean percentage difference relative to echocardiography. Multivariate regression analysis evaluated the effect of maternal characteristics on the absolute difference between echocardiography and NICOM. The mean percentage difference of cardiac output measurements between the two methods was ±17%, with mean bias of −0.13 l.min⁻¹ and limits of agreement of −1.1 to 0.84; stroke volume measurements had a mean percentage difference of ±15%, with a mean bias of −0.8 ml (−10.9 to 12.6); and heart rate measurements had a mean percentage difference of ±6%, with a mean bias of −2.4 beats.min⁻¹ (−6.9 to 2.0). Similar results were found when the analyses were confined to each individual trimester. The absolute difference between NICOM and echocardiography was not affected by maternal age, weight, height, race, systolic or diastolic blood pressure. In conclusion, NICOM demonstrated good agreement with echocardiography, and can be used in pregnancy for the measurement of cardiac function.     

Measurement of pulmonary blood flow with transesophageal two-dimensional and Doppler echocardiography

Transesophageal echocardiography permits measurement of the pulmonary artery diameter (two-dimensional echocardiography) and pulmonary artery blood flow velocity (pulsed-wave Doppler). These measurements considered with the heart rate allow for the determination of pulmonary artery blood flow, which is equivalent to cardiac output. This study compared the precision of transesophageal Doppler-derived cardiac output (DdCO) with the precision of thermodilution cardiac output (TdCO) and examined the agreement between DdCO and TdCO in 33 cardiac surgical patients. The proximal pulmonary artery diameter was measured in triplicate during systole and end expiration, and the local blood flow velocity was recorded on video tape. The instantaneous pulmonary artery blood flow velocity (centimeters per second) for three random cardiac beats was integrated with respect to time. DdCO was calculated as the product of the flow velocity integral (centimeters per beat), heart rate (beats per min), and the mean cross-sectional area (centimeters squared) of the main pulmonary artery. At the same time that the velocity recordings were made, three serial determinations of TdCO were made by an independent observer. Pulmonary blood flow could be measured in 25 of the 33 patients. The anatomical relationship among the esophagus, the left main stem bronchus, and the pulmonary artery did not allow adequate imaging of the pulmonary artery in 8 (24%) of the patients. A total of 45 sets of triplicate measurements were made. The range of cardiac outputs encountered was 1.7-6.6 l.min-1 by TdCO and 1.5-6.9 l.min-1 by DdCO. The 95% confidence limits for the difference between the two methods (agreement) was 0.030 +/- 0.987 l.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intraoperative fetal heart rate monitoring during emergency neurosurgery in a parturient

Malignant brain tumors during pregnancy are rare, and these patients seldom require immediate surgical intervention. A 27-year-old pregnant woman underwent emergency craniotomy. Anesthesia was induced with intravenous thiopental-fentanyl; it was maintained with isoflurane in oxygen and continuous intravenous remifentanil infusion. We used full stomach precautions but omitted succinylcholine for fear of increasing the intracranial pressure during induction of anesthesia. To detect fetal hypoxia and the effects of anesthesia on fetal hemodynamics, the fetal heart rate (FHR) was monitored using a fetal Doppler ultrasonography unit fixed to the mother's abdominal wall. Intraoperative and recovery periods were uneventful. Use of an isoflurane and remifentanil combination provided stable hemodynamics with adequate arterial blood pressure to avoid uterine hypoperfusion and fetal hypoxia. In this case, using FHR monitoring we found that craniotomy can be performed safely under isoflurane/remifentanil based-general anesthesia during the second trimester of pregnancy.     

Prevention of tachycardia with atenolol pretreatment for carotid endarterectomy under cervical plexus blockade.

A double-blind, randomised, controlled trial of forty patients was carried out to determine if oral atenolol pretreatment would reduce the incidence of tachycardia during carotid endarterectomy performed under cervical plexus block. Twenty patients received a placebo and twenty patients 50 mg of atenolol two hours prior to surgery. The superficial and deep cervical blocks were performed with 1.5% lignocaine containing 1:200,000 adrenaline. The patients were monitored with the V5 lead of the electrocardiogram and intra-arterial blood pressure. These measurements were recorded on a correctly calibrated paper recorder. Tachycardia (heart rate greater than 90 beats per minute for more than three minutes) occurred in thirteen patients in the placebo group and two patients in the atenolol group (P less than 0.01). There was no difference in the occurrence of bradycardia, hypotension or hypertension between the two groups. It is concluded that atenolol pretreatment is an effective method of reducing the incidence of tachycardia during carotid endarterectomy performed under cervical plexus blockade.     

Changes in oxygenation and pulse rate during endoscopy

Continuous monitoring of arterial oxygen saturation and heart rate with a pulse oximeter was performed in 100 consecutive patients undergoing esophagogastroduodenoscopy (78) or colonoscopy (22). Twenty-four patients had decreases in their estimated arterial PO2 level to less than 60 mm Hg during or just after the procedure. In 15 patients the hypoxemia was transient, but in nine others, treatment was required. Twenty patients also developed a tachycardia greater than 120 beats/minute.