Arterial desaturation and orthodeoxia after atrial septal defect repair: demonstration of the mechanism by transesophageal and contrast echocardiography.

A young woman without symptoms underwent repair of an ostium secundum atrial septal defect, and exertional dyspnea developed postoperatively. This was found to be due to arterial oxygen desaturation which was exaggerated in the upright position and with exercise. Contrast echocardiography confirmed a right-to-left shunt at the atrial level that was shown only with femoral venous contrast injection and not with upper extremity venous injection. Transesophageal echocardiography and subsequent surgical exploration found that the Eustachian valve had been mistaken for the inferior rim of the defect and sutured to the upper rim of the defect. This created a channel through which blood from the inferior vena cava could be partially deferred to the left atrium.

Antiapoptotic compound to enhance hypothermic liver preservation.

BACKGROUND: Apoptosis (programmed cell death) occurs as a consequence of global organ ischemia during isolation and storage prior to transplantation. If apoptosis is inhibited during ischemia, organ preservation should be improved, and the length of time for permissible storage may be increased. The objective of this study was to test the effect of a newly developed antiapoptotic compound, LXR-015, during extended hypothermic liver preservation. METHODS: Three groups of 12 rats each were studied. In the normal group, liver function was studied immediately after harvesting. In the study group, harvested livers were flushed with Euro-Collins solution (30 ml/kg body weight) containing LXR-015 at a concentration equivalent to 9 mg/kg animal body weight (300 microg/ml). The livers were then stored at 4 degrees C for 24 hr before liver function was studied. In the control group, harvested livers were flushed with Euro-Collins solution without LXR-015 and then stored at 4 degrees C for 24 hr before liver function was studied. RESULTS: Portal venous flow was higher (P<0.05) in the normal and study groups compared with the control group. Portal venous resistance was lower (P<0.05) in the normal and study groups compared with the control group. Liver tissue oxygen consumption in the study group was significantly higher than in both the normal and control groups (P<0.05). Liver enzyme production (aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatine kinase) was higher in the control group than in either the study or normal group (P<0.05). Bile production in both the normal and study groups was higher than in the control group (P<0.05). The liver tissue wet to dry weight ratio in both the normal and study groups was lower than in the control group (P<0.05). Histopathology studies revealed fewer apoptotic bodies (P<0.05) in both the normal (1.70+/-0.15 per high-power field) and study groups (2.08+/-0.10 per high-power field) than in the control group (7.92+/-.33 per high-power field). CONCLUSIONS: Adding an antiapoptotic compound, LXR-015, to Euro-Collins solution significantly improves hypothermic preservation of the rat liver compared with Euro-Collins solution alone.

Canine lung transplantation after more than twenty-four hours of normothermic preservation.

BACKGROUND: Consistent clinical results have not been achieved when lung preservation times exceed 6 hours. The aim of this study was to use an alternative normothermic autoperfusion technique for lung preservation and transplantation. METHODS: In six paired dogs, donor lungs were removed, along with the heart, liver, pancreas, duodenum, and both kidneys, and were preserved for 24 to 33 hours in a normothermic autoperfused multiple organ block. Orthotopic left lung transplantation was performed at the end of the preservation period. RESULTS: Lung function was good during the preservation period. With a gas mixture of 50% O2 + 3% CO2 + 47% N2 delivered to the multiorgan block, arterial oxygen tension ranged from 331 +/- 19 to 383 +/- 8 mm Hg; carbon dioxide tension ranged from 18 +/- 5 to 32 +/- 5 mm Hg; and pH ranged from 7.36 +/- 0.02 to 7.45 +/- 0.08. After transplantation, the dogs were kept anesthetized and ventilated for 24 hours with the same gas mixture. The opposite pulmonary artery was occluded 0 to 6 hours after transplantation. Arterial blood pressures were stable after surgery. Arterial oxygen tension was maintained between 205 +/- 39 and 320 +/- 57 mm Hg, and arterial carbon dioxide tension was maintained between 23 +/- 2 and 34 +/- 2 mm Hg. Lung tissue wet/dry weight ratio was 4.94 +/- 0.17 after preservation; this ratio did not differ from that found in normal controls (4.91 +/- 0.10). CONCLUSIONS: This study shows that the lungs were well preserved for more than 24 hours of preservation when the normothermic multiorgan block preparation was used. The transplanted left lung was able to support the anesthetized dog after the opposite pulmonary artery was occluded.

A systematic study of hypothermic lung preservation solutions: Euro-Collins solution.

BACKGROUND: Testing lung function after preservation is difficult because a suitable model is still lacking; thus, the effectiveness of different solutions for lung preservation has not been confirmed. This study tested the effectiveness of Euro-Collins solution alone for hypothermic preservation of rat lungs. METHODS: A living rat perfusion model was used, which allowed more than 5 hours of continuous perfusion for isolated lung function studies. Group 1 lungs (control, n = 8) were tested without preservation. In groups 2 through 6 (n = 8 lungs each), the lungs were flushed with 4 degrees C Euro-Collins solution and preserved for 4, 6, 8, 12, and 24 hours, respectively. Lung function studies were carried out after preservation. RESULTS: In groups 1 and 2, pulmonary arterial blood flow and pulmonary venous oxygen tension were higher and pulmonary resistance was lower than in the other groups. Airway pressure and resistance were lowest in group 1. Lungs in groups 5 and 6 demonstrated the worst function, but the lung tissue wet to dry ratio was higher only in group 6. CONCLUSIONS: At 4 degrees C, Euro-Collins solution can effectively preserve rat lungs for 4 hours. Six to 8 hours of preservation resulted in depressed lung function. More than 12 hours of preservation resulted in uniformly deficient lung function, rendering the lungs unsuitable for transplantation.

Chemical pleurodesis with doxycycline 1 g.

We evaluated the utility of a single 1-g dose of doxycycline in the treatment of malignant and nonmalignant pleural effusions and refractory pneumothoraces in 27 consecutive patients requiring pleurodesis. After the evacuation of all retained air or fluid, and premedication with intravenous narcotic analgesics and intrapleural lidocaine 200 mg, the patients received doxycycline 1 g in 50 ml normal saline instilled through the chest tube. This was followed by instillation of 100-200 ml of air to facilitate dispersion. The chest tube was removed when the drainage was less than 150 ml/day. Twenty-three of 27 patients were evaluated at 30 days. Six (67%) of the nine patients with pneumothoraces achieved a response, and both patients with nonmalignant pleural effusions had a complete response. Of the 12 patients with malignant pleural effusion, 8 (67%) achieved a complete response, 2 had a partial response, and 2 had no response. Twenty-two (81%) of 27 patients experienced adverse effects with pleurodesis, with pain (81%) and fever (11%) being the most prevalent. In this limited number of patients, doxycycline 1 g appeared to be safe and effective for the treatment of pleural effusions and pneumothoraces. The 1-g dose must be compared with the standard 500-mg dose and with other established agents.

delta Opioid extends hypothermic preservation time of the lung.

To test the hypothesis that a delta opioid, DADLE ([D-Ala2, D-Leu5]-enkephalin), could protect tissue from ischemic damage during hypothermic lung preservation, we studied three groups of rats. In group 1 (n = 8), lung function was studied immediately after harvesting. In group 2 (n = 8), the lung was flushed with 4 degrees C Euro-Collins solution and preserved for 24 hours. In group 3 (n = 8), the lung was flushed with 4 degrees C Euro-Collins solution plus DADLE (1 mg/kg) and preserved for 24 hours. Lung function was studied by using a living rat perfusion model. Venous blood from the host rat perfused the pulmonary artery of the isolated lung. Blood from the isolated lung was returned to the carotid artery of the host rat with a roller pump. Severe pulmonary edema, hemorrhage, and occlusive pulmonary artery resistance occurred in group 2 within 30 minutes of perfusion. Perfusion studies were carried out for more than 60 minutes in groups 1 and 3. Pulmonary blood flow was lower in group 2 than in either group 1 or group 3. Pulmonary vascular resistance was much higher in group 2 than in groups 1 and 3 (p < 0.05). Airway pressure and airway resistance were much higher in group 2 than in groups 1 and 3 (p < 0.05). Airway resistance was also higher in group 3 than in group 1 after 20 minutes of perfusion (p < 0.05). Oxygen tensions from the pulmonary vein of the isolated lung in group 2 were lower than those in groups 1 and 3 (p < 0.05). Alveolar-arterial oxygen difference was much higher in group 2 than in groups 1 and 3 (p < 0.05). Lung tissue wet/dry weight ratio after perfusion was much higher in group 2 than in groups 1 and 3. The results clearly show, for the first time, that DADLE can effectively enhance hypothermic lung preservation in rats.

Effects of internal mammary artery pedicle coronary artery bypass grafting on aortic valve leaflet positioning.

Approximately 50% of all patients who require replacement of the aortic valve (AVR) also require coronary artery bypass grafting (CABG) for concomitant coronary artery disease. Internal mammary artery (IMA) pedicle grafts are being used with increasing frequency for this purpose. Since the ostia of the IMA are considerably downstream from the sinus of Valsalva we hypothesized the CABG would change the local coronary flow dynamics and possibly alter the timing of both natural and prosthetic valve opening and closing dynamics. Both IMA'S were dissected as pedicle grafts in five pigs and the animals were put on cardiopulmonary bypass. Anastomotic sites were the proximal 1/3 of the left anterior descending and proximal 1/5 of the right coronary arteries. Aortic root, left ventricular and right ventricular pressures were measured and flowmeter transducers were placed on the aortic root, the left main coronary artery, the right coronary artery, the left IMA and the right IMA for measuring flows. Echocardiographic images of the aortic valve, in the longitudinal view, were recorded with a simultaneous ECG. Time points were defined during each cardiac cycle based upon characteristic points in the native coronary hemodynamics. These were identified at 8, 14 and 22% of the cycle (valve opening) and 38, 45 and 55% of the cycle (valve closing). Calculations were made based upon each cycle being initiated with the ECG R wave peak. Significant alterations in flow patterns were identified and quantitated between native coronary and IMA grafts. Only minor changes in valve positioning were identified. These differences in natural valve leaflet position occurred at 22% and 45% of the cycle.

Coronary vascular and myocardial effects of substance P in hypercholesterolemic rabbits.

Age-matched male New Zealand white rabbits (n = 16) were allocated to two groups: group 1 (n = 8) received a standard rabbit diet; group 2 (n = 8) received a 2% cholesterol-enriched diet. After 8 weeks of prescribed diet, hearts were excised and placed on a constant perfusion pressure Langendorff-type apparatus. Coronary flow, left ventricular pressure, and isovolumic dP/dt were continuously measured. Baseline recordings were made and then a single 5 nmol bolus dose of substance P was delivered into the coronary perfusate. Mean serum cholesterol levels in group 1 were 53 +/- 17 (SEM) mg.dl-1, in group 2 1438 +/- 143 mg.dl-1. In group 1, the injection of substance P caused mean coronary flow to increase 39 +/- 6%, mean coronary vascular resistance to decrease 28 +/- 3%, and mean dP/dt to increase 11 +/- 4%. In group 2, coronary flow increased 57 +/- 13%, coronary vascular resistance decreased 33 +/- 5%, and dP/dt increased 17 +/- 4%. Within groups, values changed significantly from baseline but these changes were not significantly different between groups. The duration of coronary flow response was 113 +/- 20 s in group 1 and 63 +/- 8 s in group 2. Substance P is a potent dilator of coronary resistance vessels and has positive inotropic effects in the rabbit. High levels of cholesterol exposure do not alter the magnitude of substance P-induced vasodilation, but the duration of the response is shortened.

Substance P induces biphasic endothelium-dependent relaxations in pig and rabbit carotid arteries.

Careful handling and preparation of freshly harvested vessels from 22 pigs and 12 rabbits revealed a two-phase vasorelaxation response to cumulative doses of substance P (SP). A rapid, transient relaxation was observed during the cumulative dose-response and a new plateau of equilibrium was seen following an increase in developed force after the last dose of SP. The phase 2 response is also produced by submaximal doses of SP and is not altered by pretreatment of the rings with Indomethacin. Acetylcholine (ACh) caused an endothelium-dependent relaxation but without evidence of a phase 2 plateau. N omega-Nitro-L-Arginine (L-NNA) and N omega-Nitro-L-Arginine Methylester (L-NAME) pretreatment resulted in a shift to the right in the phase 1 response to SP and a complete blockade of phase 2. Methylene blue caused nearly complete block of both phases. Nitroglycerin caused a dose-dependent and prolonged vasorelaxation with no phase 2.

Autoperfused heart-lung preparation: one reason for unsuccessful lung preservation.

Normothermic autoperfused heart-lung preparation has the advantages of avoiding ischemic time and allowing continuous monitoring of organ function during preservation. When this technique is used, the lungs deteriorate quickly, but the reasons for this deterioration have not been investigated. This study was designed to explore the possible cause of rapid lung deterioration. Three groups of mongrel dogs were used. In Group 1 (N = 5), a buffer bag was used in the heart-lung preparation. In Group 2 (N = 6), a 20 mu filter was incorporated between the buffer bag and the right atrium. In Group 3 (N = 5), no buffer bag was used. Average survival time was 15.0 +/- 3.1 hours in Group 1, 13.5 +/- 0.7 hours in Group 2, and 21.6 +/- 2.3 hours in Group 3. Heart function was comparable among the three groups, but the arterial pulse pressure was lower and the heart rate higher in Group 3. Both white blood cell and platelet counts decreased contonuously during the preservation period. Examination of the filters in Group 2 revealed numerous aggregates consisting of platelets, white blood cells, red blood cells, and fibrin. Small thrombi were also found in the lungs in Groups 1 and 2. The results indicated that one important reason for quick lung deterioration was numerous aggregates, which were formed in the buffer bag, returned from the venous line, and trapped in the lungs. Removal of the buffer bag reduced the production of aggregates but tended to de-stabilize the hemodynamics of the preparation.

Two-day preservation of the lungs by normothermic perfusion.

Lung function was studies during a 2-day preservation period. The lungs were removed along with the heart, liver, pancreas, duodenum, and both kidneys while they were still perfused by the heart and oxygenated by the lungs. In 12 experiments the organs survived an average of 49.2 hours. Arterial blood pressures were maintained at 74-95 mmHg, and no inotropic drugs were used. When a gas mixture of 50% O2 + 3% CO2 + 47% N2 was used, arterial oxygen tension ranged from 239 +/- 23 to 305 +/- 16 mmHg; carbon dioxide tension ranged from 17.6 +/- 1.8 to 24.9 +/- 2.9 mmHg; and pH ranged from 7.31 +/- 0.03 to 7.49 +/- 0.04. Maximum airway pressure ranged from 12.5 +/- 1.7 to 28.0 +/- 2.2 mmHg. Airway resistance ranged from 0.020 +/- 0.006 to 0.049 +/- 0.007 mmHg/ml and increased after 40 hours. Lung tissue wet/dry weight ratio was stable during the preservation period. The results showed that the lungs were well preserved in the normothermic perfusion preparation for up to two days with minimal functional changes.

Ischemic heart disease in the elderly: the role of coronary angioplasty and coronary artery bypass grafting.

Management of ischemic heart disease in the elderly is complex. Invasive therapies such as percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) are associated with significant morbidity and mortality. The short-term advantage of PTCA is that its associated noncardiac morbidity and mortality are less than that of CABG, particularly in the incidence of stroke. Unfortunately, PTCA revascularization is less complete and less durable than CABG revascularization. The advantages of CABG are that cardiac revascularization is more complete, the result is more durable, and long-term results are improved over those of PTCA. Conversely, the initial morbidity and mortality are higher for CABG and are adversely affected by factors such as recent myocardial infarction, lung disease, and renal failure. We provide an overview of the results and outcomes of PTCA and CABG in the elderly, as well as suggestions for management.

N omega-nitro-L-arginine blocks the second phase but not the first phase of the endothelium-dependent relaxations induced by substance P in isolated rings of pig carotid artery.

Endothelium-dependent relaxations can be evoked by a variety of stimuli, among them substance P (SP), which is found in sensory nerve fibers supplying the adventitia-media junction of most muscular arteries. This study determined the role of endothelium-derived nitric oxide as a mediator of endothelium-dependent relaxations to SP in isolated rings of the pig carotid artery suspended in organ chambers for isometric tension recording. SP (10(-12)-10(-7) M) caused concentration-dependent relaxations of arteries precontracted with norepinephrine (10(-7) M). The relaxations were characterized by a partially transient relaxation (phase 1) and a sustained relaxation of the artery (phase 2). The inhibitor of nitric oxide formation, N omega-nitro-L-arginine (L-NNA) methyl ester caused a gradual increase in tension, the phase I response at 3 x 10(-10) to 3 x 10(-7) M SP was shifted to the right, but the maximal relaxation was comparable in the presence of L-NNA. However, the sustained relaxation after addition of substance P (phase II) was lost and tension in the presence of L-NNA returned to a level above that induced by L-NNA and norepinephrine (10(-9) M). These results suggest that the endothelium-dependent relaxations to SP, particularly the prolonged relaxation (phase II), are due to de novo synthesis of nitric oxide and hence fully abolished by a specific inhibitor.

Comparison of transesophageal color flow Doppler imaging of normal mitral regurgitant jets in St. Jude Medical and Medtronic Hall cardiac prostheses.

Transesophageal color flow Doppler imaging of mitral mechanical prostheses is now widely used. This method eliminates the frequent problems of acoustic shadowing and flow masking that are commonly seen with a transthoracic Doppler study of mechanical mitral prostheses. Transesophageal color flow Doppler imaging was performed postoperatively in seven patients who had received St. Jude Medical mitral prostheses (St. Jude Medical, Inc., St. Jude, Minnesota) and in six patients who received Medtronic Hall mitral valves (Medtronic, Inc., Minneapolis, Minnesota). Maximal systolic regurgitant jet length and area determinations were obtained in all patients. A comparison of maximal jet lengths and areas for each type of mechanical prosthesis demonstrated that the Medtronic Hall prostheses produced longer maximal jet lengths (p = 0.0001) and larger jet areas (p = 0.0009) than those produced by the St. Jude Medical mitral valves. Medtronic Hall prostheses produce a large centrally directed jet, whereas St. Jude Medical prostheses typically generate three smaller jets. Recognition of these differences in transesophageal color flow Doppler images in these commonly used cardiac valve prostheses is necessary to avoid misinterpretation of the normally large systolic regurgitant jet of the Medtronic Hall prosthesis as representing prosthetic dysfunction.

Left ventricular outflow tract obstruction in children.

Left ventricular outflow tract obstruction is classified by site of presentation into valvular, subvalvular, and supravalvular forms. This disorder affects multiple age groups, and success rates of operative therapies vary dramatically. Abnormalities in any of the three principal anatomic sites of the LV outflow tract can lead to obstruction. Valvular stenosis is the most common, and when present in infants, carries a high mortality rate. Subvalvular stenosis is much less common and may present as a discrete ring or a diffuse tunnel. Supravalvular stenosis is the least common and likewise has discrete and diffuse forms. These various forms of obstruction require surgical relief. Each operation must be tailored to the individual patient and may comprise simple valvotomy for bicuspid aortic valve or complex intraventricular manipulations to ameliorate diffuse subaortic tunnel. The mortality for valvotomy alone can range from 0 to 70%, depending on the age of the patient at the time of surgery. Additionally, the possibility for recurrent stenoses after operation is always present. For these reasons, therapy and interventions directed toward relief of LVOTO must be considered palliative, and lifelong patient follow-up is necessary.

In extremis use of staples for cardiorrhaphy in penetrating cardiac trauma: case report.

Patients in extremis following penetrating cardiac injury must be rapidly and effectively resuscitated. Treatment priorities are relief of tamponade with control of hemorrhage. Rapid closure of cardiac wounds is necessary to achieve hemostasis and preservation of cardiac function. A simple and rapid technique of emergency cardiorrhaphy is described utilizing the skin stapling device.

Matronized nursing service at Mobile City Hospital in the mid-19th century: a paradigm of altruism and indigent patient care.

Influences upon the development and evolution of nursing groups and the profession have been multifactorial: cultural, economic, political, and social. Although monastic and chivalric orders throughout antiquity provided the beginnings with hierarchical organizations and a sense of voluntarism and vocation, it was not until the mid-19th century that the concept of a nursing service became codified and more hospital-oriented. The inception of a matronized nursing service in the Mobile City Hospital under the tutelage of the Superintendent, Dr. Willis Roberts, antedated the rapid expansion of nursing education and service recommended and instituted by Florence Nightingale. The former served as a paradigm of altruism as "women attendants" became formally associated with a hospital-based "nursing service," initially under the directorship of a lay matron, Mrs. Sarah Dubois, and subsequently under a succession of Sisters of the Roman Catholic Order of the Sisters of Charity (America). Although ostensibly instituted to render care to "female paupers," the matronized nursing service was readily expanded, and subsequently delivered care to the entire, predominantly indigent patient population. The paradigm was worthily perpetuated during the latter half of the 19th century in vitually all hospitals as nursing education and services continued to become more secularized and technologically sophisticated.

The clinical spectrum of cardiac fibroma with diagnostic and surgical considerations: noninvasive imaging enhances management.

A cardiac fibroma was successfully resected from the interventricular septum of a 25-year-old woman. The clinical data were correlated with a review of the data on 144 other patients, thereby providing a clinical profile and management strategy for this type of tumor. Initial manifestations of a fibroma were determined to be congestive heart failure (21%), tachyarrhythmias (13%), and chest pain (3.5%). A majority of patients were asymptomatic (36%) with abnormal physical findings or an abnormal chest roentgenogram. Finding the tumor at autopsy incidentally or on sudden death (23%) indicated the lethal potential. A few (3.5%) of the reports on patients with cardiac fibroma were without clinical data. Noninvasive imaging by echocardiography, computed tomography, and nuclear magnetic resonance improved the diagnosis. Surgical treatment was successful in 53 of the 84 patients for whom it was attempted.