Main Pulmonary Trunk Research Articles

Pulmonary resections for T4 non-small cell lung cancer with support of cardiopulmonary bypass

We read with much interest the article ‘Extended pulmonary resections of advanced thoracic malignancies with support of cardiopulmonary bypass’ by Wiebe et al. [1]. The authors presented in an exciting way their experience with extremely difficult surgical treatment of the pulmonary malignancies infiltrating the heart or great vessels. Such kind of surgery obviously deserves the highest level of expertise. The authors are especially congratulated for the results of treatment of sarcomas which are known for the resistance for chemotherapy and radiotherapy, the radical operation being the only curative solution in these patients. The 5-year survival of 62.5% in this group may indicate the way that kind of tumor should be managed more often in the future. Our concern, however, is themanagement of patients with advanced non-small cell lung cancer. There were three patients in the presented group, all of them T4, according to Table 2. In such group the rate of N2 involvement is very high, so the need for the thorough mediastinal staging is generally agreed upon. The authors state that all patients with NSCLC underwent cervical mediastinoscopy. This is surprising that the tracheal infiltration by pT2 nodes, which ought to have been easily discovered during mediastinoscopy, was unexpectedly found during the operation. As the authors wrote that one-third patients underwent neoadjuvant chemotherapy and radiotherapy, it would be very interesting to know what was the method of restaging in this patient. It would also be interesting to know if N2 disease was excluded during mediastinoscopy in the other two patients. The indications for use of CPB in three patients with NSCLC were emergent in one patient and unexpected in two patients. In these patients there was an infiltration of the main pulmonary trunk (patient 2), left atrium (patient 4) and

Evaluation of Intrapulmonary Vascular Dilatations With High-Resolution Computed Thorax Tomography in Patients With Hepatopulmonary Syndrome

We aimed to determine the role of thorax high-resolution computed tomography (HRCT) in demonstrating the pulmonary vasodilatation in patients with hepatopulmonary syndrome (HPS). Traditionally, the presence of intrapulmonary vascular dilatations can be detected by using one of the three diagnostic modalities: contrast-enhanced echocardiography, technetium 99 m-labeled macroaggregated albumin scan, and pulmonary angiography. The study group included 10 patients with HPS (Group 1), 12 patients with normoxemic cirrhosis (Group 2), and 12 healthy controls (Group 3). All of the subjects underwent conventional and HRCT of thorax. The diameters of pulmonary trunk, main pulmonary arteries, and right lower lobe basal segmental arteries were measured. The ratios of right lower lobe basal segmental pulmonary artery to bronchus diameter were calculated. The mean diameters of the main pulmonary trunk, right and left main pulmonary arteries were not different between the groups. Mean diameters of right lower lobe basal segmental pulmonary arteries were significantly higher in Group 1 compared with Group 2 (P=0.01) and Group 3 (P=0.002). Mean right lower lobe basal segmental pulmonary artery to bronchus ratios were significantly higher in Group 1 compared with Group 2 (P=0.03) and Group 3 (P<0.001). Group 2 had significantly higher pulmonary artery to bronchus ratios than Group 3 (P<0.001). Thorax HRCT may be helpful in the diagnosis of HPS by demonstrating the dilated peripheral pulmonary vessels or increased pulmonary artery to bronchus ratios in patients with liver disease and hypoxemia.

Truncus Arteriosus Associated with Interrupted Aortic Arch in 50 Neonates: A Congenital Heart Surgeons Society Study

Patients with both interrupted aortic arch (IAA) and truncus arteriosus (TA) have worse outcomes than those with either lesion in isolation. We determined outcomes and associated factors in this rare group. From 1987 to 1997, 50 (11%) of 472 neonates with IAA were identified with TA. Site of aortic arch interruption was distal to the left subclavian artery in 16% and between the left common carotid and subclavian artery in 84%. From the common arterial trunk, the pulmonary arteries arose from a main pulmonary trunk in 46%, common orifice in 22%, and separate orifices in 32%. At presentation, truncal valve stenosis was present in 12% and regurgitation in 22%. There were 34 deaths, with a single early hazard phase. Overall survival from admission was 44%, 39%, and 31% at 6 months, 1 year, and 10 years, respectively. One patient had primary cardiac transplantation and 4 died without any intervention. The IAA repair alone was performed in 7 patients, with single stage repair of both IAA and TA in 38 patients. Associated factors for overall time-related death include female gender (p < 0.001), type III TA (p < 0.001) and one institution (low-risk; p < 0.001). Results improved somewhat over time (p < 0.001). At 5 years after IAA repair only 28% were alive without arch repair intervention, and at 5 years after TA repair only 18% were alive without conduit reoperation. The combination of IAA and TA carries high early mortality, with high risk of reinterventions in survivors. One stage repair of both TA and IAA is the optimal management.

Morphometric study of the human fetal heart I. Arterial segment

This study measured the dimensions of the great arteries of normal human fetal hearts at an early fetal stage (between 13-20 weeks post-fertilization) in 103 fetuses obtained by necropsy. Different segments of the aorta and the pulmonary artery were dissected and their external diameters measured under stereoscopic magnification. All segments showed linear growth during this period of fetal development. Ranges in median values of external diameters associated with the pulmonary artery were: 2.1-4.2 mm for the valve ring; 2.2-4.2 mm for the main pulmonary trunk; 1.2-2.5 mm for the right pulmonary artery; 0.9-2.18 mm for the left pulmonary artery; and 4.0-8.0 mm for the length of the main pulmonary trunk. Similarly, in the aorta, median diameters were: 2.1-4.2 mm for the ascending aorta; 1.92-3.8 mm for the aortic arch; 1.45-3.0 mm for the aortic isthmus; and 1.75 -3.35 mm for the descending aorta. The diameter of the ductus arteriosus ranged between 1.2-2.45 mm. The growth rates of the pulmonary artery and the aorta were similar. The diameter of the ascending aorta was found to be greater than that of the descending aorta and the right pulmonary artery was wider than the left pulmonary artery. In addition, the magnitude of growth in the various aortic segments was different and the ratios obtained between the aortic isthmus and the ascending and descending aortae, ranged between 0.66-0.93. This study provides important morphometric reference information concerning the dimensions and growth of the great arteries of the fetal heart and has clinical application in pediatric cardiac surgery and echocardiography.

A method of using the pulmonary trunk to form a trileaflet valve

Materials and Methods Human anatomic study. Using cadavers (n 7), the main pulmonary trunk was removed and trimmed to create a tissue cylinder with a height equal to the corresponding aortic annulus diameter (Figure 1, A). Three longitudinal incisions, 2 mm less than one half the cylinder height, were positioned 120° apart (Figure 1, A). The resulting flaps were involuted and secured 2 to 3 mm from the superior rim of the cylinder with 6-0 polypropylene (Prolene; Ethicon, Inc, Somerville, NJ) sutures passed through adjacent flaps near their free edges and tied, making each a U stitch (Figure 1, B-D). The base of the involuted tissue was joined with additional 6-0 polypropylene sutures, creating interleaflet triangles and eliminating acute corners from the inner surface of the valve (Figure 1, E). The outermost wall was scalloped (Figure 1, D and E). Implantation was performed with a subcoronary, modified freehand method (Figure 1, F and G). After removal of the native leaflets, stay sutures were passed through the aortic annulus at a position corresponding to the midpoint of each excised leaflet. These were placed through the construct at the superior cut edge (as opposed to the base of the valve in the freehand method), and the construct was lowered into position (Figure 1, F). A 6-0 polypropylene suture was run along the superior aspect of the construct’s outermost wall, following the commissural pillars’ contours (Figure 1, G). Passive testing of each valve’s competency was performed under a 200 mm Hg saline column, enabling endoscopic inspection of the neoleaflets. One aortic root was positioned in a flow simulator, and transvalvular pressure gradients were determined across a range of flows (1-6 L/min, 0.9% saline). Sheep study. The valve design was tested in an adult sheep model (n 2). Before each operation, a replacement valve derived from the pulmonary trunk of a donor sheep was passively tested. The valve constructs were implanted as aortic valve replacements in the subcoronary position by the modified freehand technique described previously (Figure 1, F and G). After weaning from cardiopulmonary bypass, the valves were examined with an epicardial echocardiography probe. Regurgitant flow was determined by continuous-wave Doppler scanning in the long-axis view. Peak velocity was obtained in the one animal in which anatomic alignment of the probe allowed measurement. All animals received humane care in compliance with the “Guide for the Care and Use of Laboratory Animals” prepared by the Institute of Laboratory Resources, National Research Council.

Surgical Treatment for Primary Cardiac Leiomyosarcoma Causing Right Ventricular Outflow Obstruction

A 55-year-old man was admitted to another hospital because of dry cough and dyspnea that rapidly worsened before admission. Chest computed tomography revealed a low-density mass that nearly obstructed the main pulmonary arterial trunk. Pulmonary thromboembolism was suspected and treated with catheter-directed thrombolysis therapy. Despite optimal thrombolysis and anticoagulant therapy, his symptoms persisted. He was referred for further examination and possible surgery for presumed pulmonary thromboembolism. The mass appeared more likely to be a tumor than a thrombus on careful analysis of the magnetic resonance imaging. At surgery, the anterior wall of the main pulmonary arterial trunk, the pulmonary valve, annulus, and the right ventricular outflow tract were all invaded by what was found to be a tumor and were resected under conventional cardiopulmonary bypass. The resected area was reconstructed with a 25-mm-diameter bioprosthetic valve and Xenomedica patch. Final pathological diagnosis was primary cardiac leiomyosarcoma involving the pulmonary valve. Postoperative course was uneventful, and he was discharged 11 days after surgery without adjuvant therapy because he refused it. Ten months later, the patient was well, but a chest X-ray revealed some coin lesions in the bilateral lung fields that were thought to be metastatic tumor.

Fatal Pulmonary Embolism and Cancer - a Post Mortem Study.

Introduction: During the period of 1965–1990 and 1991–2000, two separate analyses were carried out at King's College Hospital, London, taking a retrospective review of all autopsy reports during this time. The initial aims of these reviews were to determine the number of deaths from autopsy-confirmed fatal pulmonary embolism (FPE) in hospitalised patients, and the clinical characteristics of these patients.Methodology: Cases for inclusion were identified and data derived from manually examining copies of post-mortem reports. The data form recorded the patient gender, age, race, height, weight and surgical status. In addition, evidence of DVT, myocardial infarction (MI), stroke, chronic obstructive pulmonary disease (COPD), cardiac failure, infection or cancer was recorded from the autopsy report. Cases of fatal PE were classified as occurring in either surgical (if death occurred within 8 weeks of surgery), or non-surgical patients. The outcome of fatal pulmonary embolism was recorded as the cause of death only when the post-mortem stated that embolism was the main or contributing cause of death and identified emboli present either in the main pulmonary trunk or in the proximal right or left pulmonary arteries formed from the bifurcation of the main trunk. Emboli found in the distal pulmonary arteries after further division of the right and left pulmonary arteries were not included. Emboli derived from bone marrow, fat, tumour, or amniotic fluid were also excluded from the analysis. Ethical approval for the study was obtained from the local research ethics committee. The identity of deceased patients was protected by the use of code numbers on the data forms.Results: Over the 35 year period there were 45,575 hospital deaths and 16,862 (37%) post-mortems. FPE was recorded as cause of death in 1,040 (6.2%) adult patients. Of these 85% (n=885) were in non-surgical patients, and 15% (n=155) in post-operative patients. Of the fatal pulmonary emboli, 347 of 1040 (33%) had either cancer (active malignancy) or a past history of cancer. Of this cancer group, 93% (n= 323) had an active malignancy, with 7% (n= 24) giving a past history of cancer. Cancer sites were gastro-intestinal in 34% (n= 119), lung 24% (n= 82), urological 10% (n= 33), gynaecological 8% (n= 29) and breast 8% (n= 28), 5% haematological (n= 17) endocrine 5% (n= 16), and dermatological 1% (n= 3). The majority of active cancers were found within the peritoneal cavity (60%, n= 194). Infection was the additional risk factor that was most prevalent in all those with FPE occurring in 32% (n=334), 76.3% (n=808) had one or more additional risk factors.Conclusions: Most fatal pulmonary emboli occur in non-surgical patients, cancer is a very common association (33%). Active cancer is seen in 93% of all FPE deaths associated with cancer. Intra-peritoneal cavity tumours are the commonest type to be associated with FPE. Infection is a common associated risk factor.

Surgical Reconstruction of the Left Main Coronary Artery: Fresh Autologous Pericardium or Saphenous Vein Patch

Background Isolated stenosis of the left main coronary artery is usually treated by coronary bypass surgery. However, this approach restores a less physiologic perfusion of the myocardium that leads to occlusion of the left main coronary artery, and restores only a retrograde perfusion of a rather extensive myocardial area. Coronary ostial plasty has been described as an alternative surgical technique in isolated ostial left main coronary artery stenosis without calcification. We review our experience with 15 patients. Methods After placing the patient on cardiopulmonary bypass and aortic cross clamping, the main pulmonary trunk was retracted laterally. The left main coronary artery was approached anteriorly through a curved aortotomy. Reconstruction was performed using fresh pericardial patch or saphenous vein that was tailored as a patch. Results There were no early mortality or perioperative myocardial infarctions. During mean follow-up of 55 ± 39 months, no patients had any cardiac events or required repeated coronary intervention. All patients underwent follow-up transesophageal echocardiography, which demonstrated a wide open left main coronary artery (range 3 to 8 mm), normal flow pattern by pulsed-wave Doppler, and no aneurysmal dilatation or calcification of the onlay patch. Coronary angiography and intravascular ultrasound were performed in 2 patients because of nonspecific chest discomfort. In both cases, the left main coronary artery was found to be wide open, and there were no signs of patch calcification. Conclusions Surgical reconstruction of the left main coronary artery is safe and effective for the treatment of selected cases of isolated left main stenosis. The use of autologous pericardium appears to be as safe as saphenous vein patch. Neither method was associated with postoperative aneurysmal dilatation or calcification.

Massive amniotic fluid embolism: diagnosis aided by emergency transesophageal echocardiography

A 36-year-old woman was hospitalized at term and in labor at 3-cm cervical dilatation. The early labor course was remarkable only for oxytocin augmentation and combined spinal-epidural analgesia. Eight hours after admission, tetanic uterine contractions ensued, followed by persistent fetal bradycardia. An emergency cesarean section was performed and a viable male infant was delivered. Intraoperatively, a placental abruption was identified, and disseminated intravascular coagulation and persistent hypotension developed despite resuscitative efforts. Transesophageal echocardiography revealed normal left ventricular contractility and gross enlargement of the right ventricle and main pulmonary trunk, consistent with acute right ventricular pressure overload and underloading of the left ventricle. Despite resuscitative efforts, the patient died three hours postoperatively. Autopsy showed extensive microvascular plugging of the pulmonary capillaries by fetal cells in all lung fields. This is a rare case of amniotic fluid embolism diagnosed in part and managed pre-mortem with transesophageal echocardiography and confirmed by autopsy findings.

Prenatal Features of a Truncus Arteriosus With Pulmonary Atresia and Pulmonary Circulation Derived From the Ductus Arteriosus

truncus arteriosus is a solitary great artery arising from the base of the heart and supplying the systemic, pulmonary, and coronary circulation. A truncus arteriosus is a rare cardiac defect, accounting for less than 1% of structural heart defects.1 The single great artery usually arises above a malalignment ventricular septal defect (VSD) and straddles the ventricular septum. There is variability in the origins of the pulmonary branch and whether the aortic arch is interrupted. Van Praagh and Van Praagh1 suggested classifying trunci arteriosi with VSD into 4 types. In type I, a main pulmonary artery arises from the truncal root and bifurcates into the branch pulmonary arteries. In type II, the branch pulmonary arteries are separate from the truncal root. In type III, the left pulmonary artery is supplied by a collateral from the aortic arch and does not arise from the truncal root. In type IV, the aortic arch is interrupted. A truncus arteriosus may rarely occur without a VSD. Although prenatal diagnosis of a truncus arteriosus has been reported several times,2–4 to our knowledge, the rare variant with an atretic main pulmonary trunk and normal pulmonary circulation such as the case presented here has not been described prenatally. The objective of this report was to show abnormal fetal circulation associated with a truncus arteriosus with pulmonary atresia but with well-developed pulmonary circulation derived from retrograde flow through the ductus arteriosus.

In Practice: Finding Our Way

The day Amanda was transferred to our Pediatric Intensive Care Unit (PICU), we communicated our anxiety, born of experience, by sidelong glances and terse descriptions of her array of cardiac anomalies. Like Jeremy's, but worse. No main pulmonary trunk by echocardiogram, and they couldn't find good branch pulmonary arteries. She'll need cardiac catheterization this afternoon to see if they can find anything big enough to accept a shunt. To the pediatric intensivists, the bedside physicians of the ICU, this brought up memories of several infants referred over the last few years. In the more successful cases, surgery and careful intensive care had allowed us to send home children who were still blue, but alive and active. At the other end of the spectrum were a handful of children who had undergone one or more attempts to send enough blood to the lungs to support life, but who died after a few days--or after many long months. Cardiology and surgical groups accepted Amanda into the unit, and we went to work supporting her during the evaluation. She was mechanically ventilated to control her breathing, crucial to fine tune the balance of blood flow between her lungs and her body, and she received medications by constant infusion. We hoped that the specialists involved in her care would eventually be able to send her home. We also hoped that her parents had been able to hold her and to see her awake before transfer, since it would be days before she would be able to do the things a normal baby would do--take a deep breath, out loud, or wet a diaper that her parents could change. She wasn't born lucky, with a heart like hers, but she was born down the road from one of the few centers in the country that could give her a chance at living for more than a few days. Although her parents were only twenty years old and without financial means, they were part of a large and close-knit family in a strong faith community. Since Amanda was her parents' first baby, they could devote all of their attention to her. Still, having to face this kind of challenge as hopeful new parents is almost unimaginable. Being swept into a complex and sophisticated medical system in the time needed to save this newborns life could be the best of luck--or maybe not. Amanda sailed through the catheterization without a hitch, and her parents consented to surgical placement of a shunt from a major artery to a tiny pulmonary vessel several days later. After surgery, she remained very blue because the arteries in her lungs were so small that they severely limited the amount of oxygen that her bloodstream could pick up. The medical team taking care of her included surgeons, intensivists, cardiologists, nephrologists, infectious disease specialists, nurse practitioners, clinical nurse specialists, critical care bedside nurses, respiratory therapists, physical and occupational therapists, hospital chaplains, and social workers. Others also contributed to her care, including such stalwarts of the unit as nursing assistants and ward secretaries, who supported family and staff alike. Over the next three months, her family came to know and to talk with all of us and became well versed in the lingo and details of what some call chronic critical care. They learned which alarms were worrisome and which could be listened to for a few minutes. They came to know the PICU staff on a first-name basis, met new residents as they rotated through, learned where the coffee pot was, and settled into a routine. Certain physicians were more optimistic than others, since we had as a group seen some infants whose pulmonary arteries were able to grow over time, given the chance. But Amanda's pulmonary blood flow did not improve. While she developed a personality and wrapped us all around her little finger, she remained dependent on the ventilator and IV feeding and became steadily bluer. Any exertion caused her to get suddenly worse. Owing to the breathing tube, her parents hadn't heard her since the day she was born, even when she made what they called a cry face. …

Massive pulmonary embolism in a young patient on clozapine therapy

Clozapine-associated induction of venous thromboembolism has potentially catastrophic consequences. We report a case of sudden death caused by bilateral main pulmonary trunk thrombosis in a 31-year-old man receiving clozapine therapy. The patient presented with general weakness and exertional dyspnea. Bilateral main pulmonary trunk thrombosis was clearly demonstrated by helical chest computed tomography.

Anuria due to acute bilateral renal vein occlusion after thrombolysis for pulmonary embolism

Severe hemorrhage is the more frequent complication of thrombolysis, with intracranial bleeding the most critical one. We report a 73-year-old woman with major pulmonary embolism (PE), yet haemodynamically stable, in whom thrombolysis resulted in severe complications with acute renal failure (ARF) due to bilateral renal vein occlusion, quite unexpected; this complication has never been reported, as yet. We believe that disrupture of peripheral vein clots by thrombolysis led to migration of thrombi particles upwards to the inferior vena cava (IVC) and bilateral renal vein occlusion. However, the large thrombus straddled to the bifurcation of the main pulmonary trunk and extending to the right pulmonary artery, as visualized by transthoracic (TTE) and transesophageal echocardiogram (TEE), was not affected by thrombolysis. Finally, endogenous fibrinolytic activity, under low molecular weight heparin, resulted in a slow dissolution of the pulmonary thrombus and restoration of kidney function.

Starling's law and intracellular signal transduction in 4 patients with Bland-White-Garland's syndrome

Objectives: The Bland-White-Garland-Syndrome (BWG) is a rare anomaly of the origin of the left coronary artery arising from the main pulmonary trunk. It results in chronic hypoxia of the left ventricle. The contractile performance of isolated left ventricular myocardium (trabeculae: 0.5×5.0mm) of 4 patients operated upon for BWG was analysed in detail.

Angiosarcoma of the Pulmonary Trunk Mimicking Pulmonary Thromboembolic Disease. A case report

We report on a 59-year-old male patient who suffered from dyspnea, cough and hemoptysis. Initial chest X-ray revealed a prominent right pulmonary artery (RPA) and MR imaging showed a "filling defect" within the main pulmonary trunk and RPA indicating pulmonary thromboembolic disease. Despite systemic anticoagulation, symptoms progressed. Follow-up CT showed an enlarging "filling defect" with additional extension into the left pulmonary artery as well as multiple intrapulmonary nodules. Lesion biopsy revealed a pulmonary artery angiosarcoma. Imaging findings are presented. Our case illustrates that pulmonary artery angiosarcoma should be included in the differential diagnosis of pulmonary thromboembolic disease in cases where a) symptoms do not respond to anticoagulation, b) no source of thrombi/emboli can be detected and c) pulmonary nodules/metastases develop on follow-up.

Complete augmentation of diffuse narrowing of the aorta with Williams syndrome by using an overturn approach

One-staged complete augmentation of diffuse narrowing of the aorta extending from the ascending aorta (AAo) to the descending aorta (DAo) with Williams syndrome is extremely difficult because of the lack of a good surgical approach. For the treatment of diffuse aortic stenosis, we report an innovative surgical technique involving unifocalization of the neck branch arteries and complete aortic augmentation by using an overturn approach.

Bilateral surgical coronary ostial angioplasty with a superficial femoral artery patch in Takayasu aortitis

J Thorac Cardiovasc Surg ;:

Appearance of right bundle branch block in electrocardiograms of patients with pulmonary embolism as a marker for obstruction of the main pulmonary trunk

A number of changes occur in the electrocardiogram (ECG) of pulmonary embolism. This article deals with the diagnostic value of the newly emerged right bundle branch block (RBBB) as a manifestation of acute right ventricular overload. A certain correlation between the extent of obstruction of the pulmonary artery and the appearance of RBBB is established through dynamic monitoring of the ECG. Fifty cases of dissectionally proven pulmonary embolism are observed, in 20 of which massive trunk obstruction had taken place, and in the remaining 30 peripheral embolism in the pulmonary artery was established. With 80% of the trunk embolism patients (16 cases), a newly emerged RBBB was detected in their ECG, and with the remaining 20% (4 cases), ST-segment depression and T-wave inversion in leads V 1-V 4 were observed as well as right axis deviation. S 1Q 3T 3 syndrome was detected among 60% (12 cases) of trunk embolism patients. In none of the peripheral embolism cases was RBBB in the ECG registered. Thus, its appearance on dynamic monitoring of the ECG of pulmonary embolism patients is a significant sign of the probability of massive obstruction of the main pulmonary trunk.

WS06‐07Examination of the fetal heart by five short‐axis views: The optimal screening method for fetal cardiac anomalies?

‘Classic’ fetal echocardiography is based on 7 transverse planes: the upper abdomen, the traditional four‐chamber view, the five‐chamber view in which the aortic root is visualized, and the fourth transverse view revealing the bifurcation of the pulmonary arteries, and long‐axis views of the outflow tracts and aortic arch. We recently proposed the three vessel and trachea (3VT) plane of insonation be added, to facilitate and expedite fetal heart evaluation.The (3VT) is the most cephalad transverse view, visualized on a plane crossing the fetal upper mediastinum. It is obtained easily by moving the transducer cephalad and slightly oblique from the FCV, and shows the main pulmonary trunk (MPA) in direct communication with the ductus arteriosus (DA). A transverse section of the aortic arch is seen to the right of the MPA and DA. Cross sections of the superior vena cava (SVC), and posterior to it the trachea, are visualized.The clinical applicability of the 3VT was demonstrated in a recent study encompassing 1263 low‐and high‐risk cases scanned between 14 and 24 weeks' gestation. We consider one of the greatest advantages of our novel approach the ease with which the examiner can scan the fetal heart, beginning with the caudal upper‐abdomen view. By sliding the transducer cephalad in one continuous motion, all the pertinent views are readily visualized. It was also shown to be effective in the diagnosis of such aortic arch anomalies as right and double aortic arch, among others.We showed that five short axis views including the 3VT simplified and streamlined fetal cardiac examination, without compromising diagnostic effectiveness.

Reflex responses from the main pulmonary artery and bifurcation in anaesthetised dogs

This study was undertaken to determine the reflex cardiovascular and respiratory responses to discrete stimulation of pulmonary arterial baroreceptors using a preparation in which secondary modulation of responses from other reflexes was prevented. Dogs were anaesthetised with α-chloralose, artificially ventilated, the chests widely opened and a cardiopulmonary bypass established. The main pulmonary arterial trunk, bifurcation and extrapulmonary arteries as far as the first lobar arteries on each side were vascularly isolated and perfused through the left pulmonary artery and drained via the right artery through a Starling resistance which controlled pulmonary arterial pressure. Pressures distending systemic baroreceptors and reflexogenic regions in the heart were controlled. Reflex vascular responses were assessed from changes in perfusion pressures to a vascularly isolated hind limb and to the remainder of the subdiaphragmatic systemic circulation, both of which were perfused at constant flows. Respiratory responses were assessed from recordings of efferent phrenic nerve activity. Increases in pulmonary arterial pressure consistently evoked increases in both perfusion pressures and in phrenic nerve activity. Both vascular and respiratory responses were obtained when pulmonary arterial pressure was increased to above about 30 mmHg. Responses increased at higher levels of pulmonary arterial pressures. In 13 dogs increases in pulmonary arterial pressure to 45 mmHg increased systemic perfusion pressure by 24 ± 7 mmHg (mean ± S.E.M.) from 162 ± 11 mmHg. Setting carotid sinus pressure at different levels did not influence the vascular response to changes in pulmonary arterial pressure. The presence of a negative intrathoracic pressure of -20 mmHg resulted in larger vascular responses being obtained at lower levels of pulmonary arterial pressure. This indicates that the reflex may be more effective in the intact closed-chest animal. These results demonstrate that stimulation of pulmonary arterial baroreceptors evokes a pressor reflex and augments respiratory drive. This reflex is likely to be elicited in circumstances where pulmonary arterial pressure increases and the negative excursions of intrathoracic pressure become greater. They are likely, therefore, to be involved in the cardio-respiratory response to exercise as well as in pathological states such as pulmonary hypertension or restrictive or obstructive lung disease.