PubMed Health⌕ Search

Biomedical subjects

F L Hanley

Publications and source records attributed to F L Hanley.

At least 127 records · Page 7Linked to original sources
PubMed1995

Factors influencing early and late outcome of the arterial switch operation for transposition of the great arteries.

Between January 1983 and January 1992, 470 patients underwent an arterial switch operation at our institution. An intact (or virtually intact) ventricular septum was present in 278 of 470 (59%); a ventricular septal defect was closed in the remaining 192. Survivals at 1 month and 1, 5, and 8 years among the 470 patients were 93%, 92%, 91%, and 91%, respectively. The hazard function for death (at any time) had a rapidly declining single phase that approached zero by one year after the operation. Risk factors for death included coronary artery patterns with a retropulmonary course of the left coronary artery (two types) and a pattern in which the right coronary artery and left anterior descending arose from the anterior sinus with a posterior course of the circumflex coronary. The only procedural risk factor identified was augmentation of the aortic arch; longer duration of circulatory arrest was also a risk factor for death. Earlier date of operation was a risk factor for death, but only in the case of the senior surgeon. Reinterventions were performed to relieve right ventricular and/or pulmonary artery stenoses alone in 28 patients. The hazard function for reintervention for pulmonary artery or valve stenosis revealed an early phase that peaked at 9 months after the operation and a constant phase for the duration of follow-up. Incremental risk factors for the early phase included multiple ventricular septal defects, the rapid two-stage arterial switch, and a coronary pattern with a single ostium supplying the right coronary and left anterior descending, with a retropulmonary course of the circumflex. The need for reintervention has decreased with time. The arterial switch operation can currently be performed early in life with a low mortality risk (< 5%) and a low incidence of reintervention (< 10%) for supravalvular pulmonary stenosis. The analyses indicate that both the mortality and reintervention risks are lower in patients with less complex anatomy.

Child, Preschool↗
PubMed1995

Performance of right ventricle to pulmonary artery conduits after repair of truncus arteriosus: a comparison of Dacron-housed porcine valves and cryopreserved allografts.

Repair of complex congenital heart defects often requires the use of extracardiac conduits. These repairs can be technically accomplished with excellent early results. However, the long-term performance of various conduits is less than optimal. In this report, we examined the long-term outcome of xenograft valved Dacron conduits and cryopreserved allograft valved conduits used for reconstruction of the right ventricular outflow tract in young patients with truncus arteriosus. A retrospective review was performed on 222 patients who underwent primary surgical repair of truncus arteriosus between January 1975 and December 1994 using a xenograft valved synthetic conduit (group I; n = 175) or with a cryopreserved valved allograft conduit (group II; n = 47). Median age at repair was 121 days in group I and 70 days in group II; median weight of patients in both groups was the same (4.2 kg). Conduit-related early deaths occurred in 5.7% (10/175) of patients in group I and none in group II. In a cohort of age-matched patients, actuarial freedom from conduit-related reintervention at 5 years follow-up was significantly better (P = .037) for the cryopreserved valved allograft conduits when compared with xenograft valved synthetic conduits. However, this difference was not apparent by 7 years. Multivariate analysis showed conduit size (P = .0005) as a significant predictor of early conduit-related reintervention. This study shows that mid-term performance of cryopreserved allografts (which have the advantage of technical ease of insertion of availability of small sizes for use in neonates), is better than the xenograft Dacron conduits.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1994

Maturational and hemodynamic factors predictive of increased cyanosis after bidirectional cavopulmonary anastomosis.

Bidirectional cavopulmonary anastomosis (BCA) is thought to be beneficial in the palliation of patients with univentricular congenital heart disease considered at high risk for Fontan repair. Experience with patients undergoing BCA suggested that those who were older or larger at the time of surgery tended to be more cyanotic postoperatively than their younger and smaller counterparts. This study was designed to identify correlates of systemic arterial oxygen saturation after BCA. Specifically, it was postulated that maturational changes in blood flow distribution might be associated with decreasing arterial oxygen saturation. Database records of all 110 patients undergoing BCA at our institution from June 1988 until the end of 1991 were reviewed. Postoperative catheterization data were available for 66 patients. Twenty-one patients were excluded because they had potentially reversible causes of cyanosis yielding inestimable degrees of error in hemodynamic calculations. In the remaining 45 patients, univariate and multivariate regression analyses were used to identify correlates of systemic arterial oxygen saturation. Growth and maturation as represented by body surface area exhibited a highly significant inverse correlation with arterial oxygen saturation (p = 0.005), as did pulmonary vascular resistance (p = 0.003). Patients who underwent BCA when > 3.9 years of age or with body surface area > 0.65 m2 were at significantly increased risk for excessive postoperative cyanosis, defined as systemic arterial oxygen saturation < or = 75% (p < 0.005). The interval between surgery and catheterization correlated directly with arterial oxygen saturation (p = 0.002), indicating a tendency toward earlier study of more cyanotic patients. None of the other variables examined correlated significantly with arterial oxygen saturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Total anomalous pulmonary venous drainage in newborns with visceral heterotaxy.

Children with visceral heterotaxy often present with total anomalous pulmonary venous drainage (TAPVD) associated with univentricular congenital heart disease. We reviewed our experience with the primary surgical management of this lesion under these circumstances. Over a recent 10-year span, 38 patients within the first 3 days of life were admitted to our institution and underwent primary palliation. Twenty-one of them had TAPVD, 18 to a systemic vein. Twelve (67%) of these 18 were seen with obstruction of the anomalous connection and underwent emergency operation. In 7 patients, repair of TAPVD was combined with a systemic-pulmonary artery shunt because of additional obstruction of the pulmonary blood supply, with two deaths. One patient had primary shunting and then repair of TAPVD. Four patients underwent repair of TAPVD alone. Two of them then showed signs of insufficient pulmonary blood flow, received a shunt in a second procedure, and subsequently died. Early mortality in the group with obstructed TAPVD was thus 4 (33%) of 12 patients. Statistical analysis of all 38 patients (univariate analysis, chi 2 testing) showed that neither the presence of TAPVD (p = 0.7) nor TAPVD repair alone (p = 0.8) or with shunting (p = 0.8) was a definite risk factor for early death. The performance of a shunt during the first operation, however, was associated with lower early mortality (p = 0.03). Total anomalous pulmonary venous drainage is a common finding in newborns with visceral heterotaxy. Its presence and its subsequent early repair (requiring cardiopulmonary bypass) do not increase the mortality risk. The need of a concomitant shunt in obstructed TAPVD can initially be underestimated.

Heart Defects, Congenital↗
PubMed1994

New approach to great-vessel reconstruction in transposition complexes with interrupted aortic arch.

Interrupted aortic arch can be associated with transposition of the great arteries with ventricular septal defect and with the Taussig-Bing anomaly. This usually results in a marked disparity between the hypoplastic ascending aorta and the dilated main pulmonary artery. Currently, standard arterial switch and arch repair is a widely applied approach to the surgical management of these lesions. Though the morphology of the great vessels in these lesions does not preclude this approach, the great-vessel mismatch can result in difficulties at and beyond the proximal neo-aortic to ascending aortic suture line that cause excessive bleeding, obstruction, tension, distortion, and the need of patch augmentation of the ascending aorta or arch with nonviable material. We present an alternative surgical approach used in 2 patients, 1 with Taussig-Bing anomaly and interrupted aortic arch and the other with transposition of the great arteries, ventricular septal defect, and interrupted aortic arch, that greatly simplifies the reconstruction of the neo-aorta and repair of the interrupted arch and avoids these potential hazards.

Anastomosis, Surgical↗
PubMed1994

Management and outcome of low birth weight neonates with congenital heart disease.

In 100 consecutive neonates with birth weights < or = 2500 gm (range, 540 to 2500 gm; median, 2200 gm), major congenital heart disease (excluding patent ductus arteriosus, isolated atrial septal defect, and ventricular septal defect) was diagnosed between January 1987 and January 1991; 46 had ductus-dependent lesions. Of the 100 neonates, 30 had genetic aberrations or significant associated congenital anomalies. The four most common cardiac diagnoses were tetralogy of Fallot with or without pulmonary atresia (n = 16); coarctation of the aorta (n = 12); transposition of the great arteries (n = 11); and common atrioventricular canal (n = 11). The hospital survival rate for the entire group of 100 neonates was 70%. The patients were separated into three groups on the basis of the time of intervention. Group 1 (early intervention) included 62 infants. These neonates (including 31 with ductus-dependent lesions) had surgical or catheter intervention during the initial hospitalization (median age, 9 days), all at weights < or = 2500 gm. The hospital survival rate was 81% (50/62); survival rates for palliation (78%, 18/23) and for correction (82%, 32/39) were similar. There were 26 neonates in group 2 (late intervention). These neonates did not have surgical intervention during the initial hospitalization. All were managed medically; survivors were discharged and had surgical procedures later (at a median age of 4.3 months). Six neonates (23%) died during medical management; all 20 survivors returned and had surgical procedures, with 90% survival. Overall survival rate for this group was 69% (18/26). The remaining 12 patients (group 3) had complicating features that precluded intervention; none survived. On the basis of these results, we conclude that early intervention, even with corrective surgery, can be performed in low birth weight neonates with an acceptable mortality rate. Prolonged medical therapy to achieve further weight gain did not appear to improve the survival rate.

Cardiac Catheterization↗
PubMed1994

Fetal heart block: a new experimental model to assess fetal pacing.

Epicardial fetal pacing via thoracotomy has the potential of being a safer and more reliable procedure to treat congenital complete heart block (CHB) associated with fetal hydrops refractory to medical therapy. To assess the acute electrophysiological characteristics of two ventricular epicardial leads, a new experimental model of fetal heart block induced by cryosurgical ablation of the AV node without the need for fetal cardiac bypass was performed in 12 pregnant ewes at 110-115 days gestation. A modified screw-in lead (1 1/2 turns) was used in six fetal lambs and a stitch-on lead in the other six lambs. CHB was achieved in 100% of the fetal lambs, with no ventricular escape rate noticed in any of the lambs. The acute stimulation thresholds were consistently low for both leads, with lower values for the screw-in lead at pulse duration below 0.9 msec (P < 0.03). Current measured at voltage threshold with pulse width below 0.5 msec was lower for the screw-in lead (P < 0.048). Stimulation resistance, measured during constant-voltage pacing, was not statistically different between the two leads (441.8 +/- 13.7 omega for the screw-in lead vs 480.2 +/- 59.2 omega for the stitch-on lead). No significant differences (P > 0.20) were found in R wave amplitude between the two electrodes. Slew rates were significantly higher in the screw-in group than in the stitch-on group (1.40 +/- 0.2 vs 0.62 +/- 0.2 V/sec, P = 0.04). This model of CHB is a simple and reproducible method to assess fetal pacing. We find the screw-in electrode to be a better option when fetal pacing is indicated.

Animals↗
PubMed1994

Fetal cardiac surgery.

Elucidation of the mechanisms of placental dysfunction after bypass and the negative effects of fetal stress (Fig 9) has allowed these issues to be addressed effectively using indomethacin and appropriate fetal anesthesia. The effective management of these two major problems has made a dramatic difference in the ability of fetal animals to survive surgical intervention and extracorporeal circulation. Characterization of various aspects of placental vascular hemodynamics using the isolated placental preparation also has added new insights into the behavior of the placental vasculature during extracorporeal circulation. These insights have been and will continue to be extremely useful in designing the ideal method of fetal extracorporeal circulatory support. In spite of these advances, further work remains before clinical application of these techniques can be applied reliably. Ideally, a specific blocker of the mediators of the placental response to cardiac bypass should be available before clinical studies are undertaken. Indomethacin, although quite effective, may have secondary effects on other vascular beds that would be potentially detrimental. Also, although the fetal stress response can be blocked adequately using fetal total spinal anesthesia, with a dramatic improvement in cardiovascular stability, this technique of anesthesia not only would be cumbersome, but also would be potentially dangerous in the human fetus. High-dose narcotic anesthesia has been shown to be very effective in neonates and infants undergoing cardiac procedures, with respect to both blockage of the stress response and maintenance of cardiac function. This technique also may be applicable in the human fetus as an effective method of blocking the stress response without causing myocardial depression or affecting peripheral vascular resistances. Unfortunately, sheep do not possess opiate receptors and, therefore, are not an appropriate model for testing narcotic anesthesia in the fetus. Future studies in the primate model using high-dose narcotic anesthesia could provide important information regarding this problem. Also, the ideal circuitry for fetal extracorporeal support has not been determined with certainty. Although a simplified circuit without an oxygenator is possible if the placenta is used as the oxygenator, this method has the disadvantages of high flow rates and placental stimulation. Extracorporeal circulation with the inclusion of an artificial oxygenator requires a somewhat more complex circuit; however, more manageable flow rates and less stimulation of placental vasculature are possible with this technique (Fig 10). All forms of fetal intervention for cardiovascular disease require an extensive understanding of the fetal pathophysiologic responses to intervention, whether the intervention involves open techniques that necessitate extracorporeal circulatory support or closed interventional techniques.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Inhibition of the fetal stress response improves cardiac output and gas exchange after fetal cardiac bypass.

Cardiac bypass in late-gestation fetal lambs causes severe placental vasoconstriction, which leads to fetal death from hypoxemia and respiratory acidosis. This response can be blocked by the administration of indomethacin; however, a fatal metabolic acidosis then gradually develops in the fetus. Because the fetus is known to mount an intensive catecholamine response to stress, and because the fetal myocardium is particularly sensitive to increased afterload, we hypothesized that elevated afterload as a result of fetal stress contributes to diminished cardiac output after bypass. Twenty fetal lambs at 80% gestation underwent 30 minutes of normothermic cardiac bypass at flow rates of 200 to 500 ml/kg per minute. All ewes received general anesthesia with ketamine. In 10 fetuses general anesthesia was specifically designed not to inhibit the release of stress-related catechols (ketamine); the remaining 10 fetuses received a "high" (cisterna magna) total spinal anesthetic with tetracaine, to block the fetal stress response. In each anesthetic group, 5 of the 10 lambs received indomethacin. During operation, normal hemodynamics were preserved in the spinal anesthetic group. Cardiac output, placental blood flow, and arterial carbon dioxide tension were all improved relative to results in the ketamine group. When spinal anesthesia and indomethacin are both given, hemodynamics also approach normal after bypass, and gas exchange is further improved. These data suggest that the inhibition of the stress response by spinal anesthesia improves the hemodynamic status of the fetus during operation and, in combination with indomethacin, allows maintenance of near-normal placental function after fetal cardiac bypass. Similar responses may also be possible in human fetuses with use of a high-dose narcotic technique.

Anesthesia, Spinal↗
PubMed1994

Long-term survivors of fetal cardiac bypass in lambs.

The initial experience with cardiac bypass in fetal lambs resulted in early fetal death from placental insufficiency. Subsequent work in our laboratory indicated that vasoactive cyclooxygenase products were released as mediators of this response. The placental dysfunction could be blocked by the administration of indomethacin, allowing longer fetal survival. This unmasked a more subacute (but fatal) problem: fetal surgical stress resulted in diminished fetal cardiac output and progressive metabolic acidosis and contributed to the placental vasoconstriction. In acute studies, when indomethacin was given and the stress response was inhibited by the use of total spinal anesthesia, the fetus maintained normal blood gas levels, cardiac output, placental blood flow, and acid-base status for several hours after bypass. We hypothesized that beyond this point, no further fetal or placental compromise would occur and that this management technique would thus allow long-term fetal survival. With the use of total spinal anesthesia and sterile technique for long-term study, 12 fetal lambs at 120 days (80%) gestation underwent exposure, line placement, and cannulation for fetal cardiac bypass. Indomethacin was given intravenously on obtaining venous access. After 20 minutes of normothermic cardiac bypass at flow rates of 250 to 300 ml/kg/min, the fetus was weaned from bypass, the cannulas and lines were removed, the uterus and abdomen were closed, and the ewe and fetus were allowed to recover. There was one maternal death (pneumonia) and one early abortion (of twins); the remaining 10 ewes progressed to term. At term, five healthy lambs that had undergone fetal cardiac bypass were delivered (including one twin), four ewes delivered a mummified study fetus and one or two healthy siblings, and one delivered a dead term fetus. With the use of techniques that inhibit fetal stress and block placental vasoconstriction, cardiac bypass can be performed in single-gestation fetal lambs with a high degree of recovery and survival (80% in this study). The cause of the elevated abortion rate associated with twin gestation is unclear.

Abortion, Veterinary↗
PubMed1994

High-dose steroids prevent placental dysfunction after fetal cardiac bypass.

Surgical treatment of certain congenital heart lesions in utero may have a therapeutic advantage over postnatal repair or palliation. For fetal heart surgery to be possible, a method to support the fetal circulation is necessary. Early experimental attempts at fetal cardiac bypass were unsuccessful because of increased placental vascular resistance during and after fetal cardiac bypass, which led to decreased placental flow, fetal asphyxia, and death. Our laboratory has demonstrated that the administration of indomethacin (a cyclooxygenase inhibitor) during fetal cardiac bypass prevents this increase in placental vascular resistance during and after fetal cardiac bypass. The specific mechanism by which indomethacin achieves this effect is likely to be either by inhibiting the production of a placental vasoconstrictive prostaglandin or by diverting substrate from the cyclooxygenase pathway to the lipoxygenase pathway, thereby potentially increasing the production of a placental vasodilating leukotriene. To examine these potential mechanisms in more detail, we inhibited both prostaglandin and leukotriene synthesis at the phospholipase stage with high-dose steroids. Fourteen fetal lambs were used in the study. Six animals received indomethacin (3 mg/kg), four received high-dose steroids (Solu-Medrol 50 mg/kg), and four animals were used as controls. Observations were made during a 1-hour prebypass period, a 30-minute bypass period, and a 2-hour postbypass period. Placental blood flow and placental vascular resistance were calculated at four times during the experiments: before sternotomy; after sternotomy; during bypass at 30 minutes; and 30 minutes after cessation of bypass. Similar to indomethacin, high-dose steroid administration during fetal cardiac bypass prevents the rise in placental vascular resistance and preserves placental blood flow during and after fetal cardiac bypass. This study suggests that the production of a placental vasoconstrictive prostaglandin is responsible for the increase in placental vascular resistance and decrease in placental blood flow observed after fetal cardiac bypass.

Animals↗
PubMed1993

A comparison of the perioperative neurologic effects of hypothermic circulatory arrest versus low-flow cardiopulmonary bypass in infant heart surgery.

BACKGROUND: Hypothermic circulatory arrest is a widely used support technique during heart surgery in infants, but its effects on neurologic outcome have been controversial. An alternative method, low-flow cardiopulmonary bypass, maintains continuous cerebral circulation but may increase exposure to known pump-related sources of brain injury, such as embolism or inadequate cerebral perfusion. METHODS: We compared the incidence of perioperative brain injury after deep hypothermia and support consisting predominantly of total circulatory arrest with the incidence after deep hypothermia and support consisting predominantly of low-flow cardiopulmonary bypass in a randomized, single-center trial. The criteria for eligibility included a diagnosis of transposition of the great arteries with an intact ventricular septum or a ventricular septal defect and a planned arterial-switch operation before the age of three months. RESULTS: Of 171 patients with D-transposition of the great arteries, 129 (66 of whom were assigned to circulatory arrest and 63 to low-flow bypass) had an intact ventricular septum, and 42 (21 assigned to circulatory arrest and 21 to low-flow bypass) had a ventricular septal defect. After adjustment for diagnosis, assignment to circulatory arrest as compared with low-flow bypass was associated with a higher risk of clinical seizures (odds ratio, 11.4; 95 percent confidence interval, 1.4 to 93.0), a tendency to a higher risk of ictal activity on continuous electroencephalographic (EEG) monitoring during the first 48 hours after surgery (odds ratio, 2.5; 95 percent confidence interval, 1.0 to 6.4), a longer recovery time to the first reappearance of EEG activity (only in the group with an intact ventricular septum, P < 0.001), and greater release of the brain isoenzyme of creatine kinase in the first 6 hours after surgery (P = 0.046). Analyses comparing durations of circulatory arrest produced results similar to those of analyses comparing treatments. CONCLUSIONS: In heart surgery in infants, a strategy consisting predominantly of circulatory arrest is associated with greater central nervous system perturbation in the early postoperative period than a strategy consisting predominantly of low-flow cardiopulmonary bypass. Assessment of the effect of these findings on later outcomes awaits follow-up of this cohort.

Brain Ischemia↗
PubMed1993

Preoperative management of neonatal tetralogy of Fallot with absent pulmonary valve syndrome.

In tetralogy of Fallot with absent pulmonary valve syndrome, aneurysmal enlargement of the central pulmonary arteries can be associated with severe bronchial stenosis and respiratory distress in the neonatal period. The ventilatory status of these patients must be stabilized before diagnostic and therapeutic interventions can be performed. This report describes the experience with prone positioning and emergency sternotomy in the preoperative care of a neonate.

Aneurysm↗
PubMed1993

Fate of small homograft conduits after early repair of truncus arteriosus.

Neonatal repair of truncus arteriosus is being performed in a number of centers, often with the use of small homograft conduits. The fate of the homograft and the risk of replacement were the subjects of this study. Between January 1987 and October 1991, 43 infants aged less than 3 months (range, 3 to 90 days) underwent primary repair of truncus arteriosus including implantation of a valved homograft conduit (diameter, 7 to 12 mm). Twenty-nine had follow-up of more than 6 months (range, 6 to 65 months; mean, 21.9 months). After a mean period of 31 months (range, 8 to 65 months), 7 patients showed obstruction with right ventricular pressures at least 75% systemic and underwent either a conduit change (n = 5) or a patch augmentation (n = 2). Mean cardiopulmonary bypass time at reoperation was 99 minutes; mortality was zero. Five other children are known to have a right ventricular pressure of 50% to 60% systemic, 2 having undergone balloon dilation. Statistical comparison of the patients with conduit reoperation or high right ventricular pressure (n = 12) with the rest of the population (n = 17) revealed an elevated pulmonary artery to right ventricular pullback gradient on postoperative day 1 after the repair (7.7 versus 1.3 mm Hg; p = 0.001) and choice of an aortic over a pulmonary homograft (100% versus 64.7%; p = 0.065) as significant risk factors. Age and weight at repair, postoperative pulmonary artery pressure, length of follow-up, and size of the homograft showed no significant differences between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1993

Reconstruction of hypoplastic aortic arch and coarctation in a 720-gram premature infant.

The case of a 720-g infant born at 29 weeks of gestation who underwent successful surgical correction of a hypoplastic aortic arch and aortic coarctation is presented. The infant was initially brought to surgery with an echocardiographic diagnosis of patent ductus arteriosus with left to right shunt unresponsive to indomethacin therapy. The correct diagnosis of hypoplastic aortic arch and severe coarctation with ductal dependent blood flow to the lower body was made intraoperatively. This case illustrates the danger of limited diagnostic testing in premature infants assumed to have isolated patent ductus arteriosus, and also that these small infants can undergo successful surgical repair of complex aortic arch lesions.

Aorta, Thoracic↗
PubMed1993

Halothane as an anesthetic for fetal surgery.

Halothane has become the preferred anesthetic agent during fetal surgery because it can be administered via maternal inhalation and it improves surgical exposure by relaxing the uterus. However, the effects of halothane anesthesia on fetal cardiovascular homeostasis during fetal surgery have not been documented. In 10 pregnant ewes, inhalation halothane anesthesia was administered and their fetuses were instrumented for cardiovascular evaluation. During a 1-hour period we evaluated the acute effects of halothane anesthesia on fetal hemodynamics, arterial blood gases, cardiac output, placental blood flow, total vascular resistance, systemic vascular resistance, and placental vascular resistance. Fetal cardiac output and placental blood flow were determined by the radiolabelled microsphere technique and resistances were calculated using pressure and flow data. These findings were compared to both the results we obtained in 15 fetal sheep anesthetized with the maternal administration of intravenous ketamine, and to the accepted values found in nonanesthetized, chronically instrumented fetal sheep. Our findings indicate that with halothane anesthesia during fetal surgery fetal cardiac output and placental blood flow significantly decrease, and total vascular resistance increases. Placental vascular resistance increases out of proportion to systemic vascular resistance, resulting in the shunting of blood away from the placenta. The combination of decreased cardiac output and increased shunting of blood away from the placenta causes depressed respiratory gas exchange. These findings are not present with other anesthetic agents. Halothane has significant negative effects on both the fetal heart and the peripheral vasculature which disrupt fetal cardiovascular homeostasis. Halothane is a poor anesthetic during fetal intervention.

Anesthesia, Inhalation↗