Paraganglioma of the interatrial septum.

The case of a patient undergoing successful resection of an interatrial septal paraganglioma is presented. The diagnosis of an interatrial mass was established preoperatively by echocardiography, ultrafast cine computed tomographic scan, and cardiac catheterization. The tumor was excised in total, and the interatrial septum and the roof of the left atrium were reconstructed using a bovine pericardial patch.

Repair of ventricular septal rupture through the right atrium.

The right atrial approach for repair of ventricular septal rupture associated with myocardial infarction is an alternative technique to the conventional approach of exposing the septum through the left ventricle. This technique may be combined with mitral valve replacement, infarct excision, or aneurysm resection, by avoiding a direct incision in the ventricle reduce postrepair bleeding and impairment of ventricular contractile function. We present a case of ventricular septal rupture repaired through the right atrium and review our surgical technique. This technique may be applied to most cases of ventricular septal rupture, and is particularly useful when the ventricular wall is not infarcted or aneurysmal, and the defect involves the central portion of the muscular septum, the inlet septum, and the subaortic and membranous area.

Normothermic retrograde cardioplegia is effective in patients with left ventricular hypertrophy. A prospective and randomized study.

Twenty patients with left ventricular hypertrophy (LVH) undergoing isolated aortic valve replacement were prospectively randomized to receive either continuous retrograde normothermic (n = 8) or intermittent retrograde hypothermic (n = 12) methods of myocardial protection. Biopsies of the left ventricular septum were evaluated for ultrastructure and assayed for ATP. There was no mortality, no requirement for intra-aortic balloon pump nor neurological events in any of the patients from either group. Myocardial ATP (warm 23.2 +/- 1.8 nmol/mg protein; cold 22.4 +/- 1.2 nmol/mg protein; p = 0.72) and myocardial CPK-MB (warm 43.6 +/- 5.2 U/l; cold 39.0 +/- 2.5 U/l; p = 0.67) were not significantly different. Ultrastructure was generally well preserved in the biopsies from both groups, with the exception of one patient in the normothermic group. Systemic lactate sampled after 40 minutes of cardiopulmonary bypass was significantly higher in the normothermic group (warm 3.4 +/- 0.27 mmol/l; cold 2.3 +/- 0.21 mmol/l; p = 0.01), however, the myocardial lactate production was not significantly different between the two groups (extraction ratio; warm 0.01 +/- 0.3; cold 0.13 +/- 0.1; p = 0.45). We conclude that the continuous normothermic retrograde method of myocardial protection is effective in patients with left ventricular hypertrophy; however, the higher systemic lactate levels using this technique raises concerns regarding the adequacy of systemic perfusion at 37 degrees C.

Coronary artery bypass grafting after pneumonectomy.

Coronary artery bypass grafting was carried out in a 61-year-old man 42 years after he had undergone right pneumonectomy. At the time of operation, the heart was displaced into the right hemithorax, which required modification of the operative techniques. Despite poor pulmonary function tests results preoperatively, the patient had an uneventful postoperative course. The success in this patient may be attributed to careful preoperative preparation, flexibility in the choice of techniques for establishment of cardiopulmonary bypass and coronary artery bypass grafting, and careful attention to perioperative fluid management.

Effect of sternotomy and coronary bypass surgery on postoperative pulmonary mechanics. Comparison of internal mammary and saphenous vein bypass grafts.

Coronary artery bypass grafting (CABG) is commonly performed via a median sternotomy with a reversed saphenous vein (SV) and/or an internal mammary artery (IMA) graft. Sternotomy and IMA harvesting may adversely affect postoperative respiratory function (PFTs) as disruption of the sternun may impair chest wall stability, and the decrease in intercostal muscle blood supply after removal of the IMA may reduce the force of respiration. We compared preoperative and six- to eight-week postoperative PFTs in patients undergoing CABG. The results were independent of age, sex, number of grafts, aortic cross clamp time, duration of bypass run, and postbypass fluid gradient. It was concluded that sternotomy caused a decrease in postoperative PFTs and that IMA harvesting may be accompanied by greater impairment in PFTs than when SV grafts alone were used.

Pulmonary complications of a roller pump right ventricular assist device.

The pulmonary effects of a right ventricular assist device (RVAD) were evaluated in a model of ischemic right ventricular (RV) failure. The right coronary artery (RCA) was ligated for 240 min in 12 mongrel dogs. Group 1 (n = 5) was supported medically (iv fluids, epinephrine); Group 2 (n = 7) had an RVAD instituted 30 mins after RCA ligation, but no inotropic support was given. The RVAD was a standard roller pump providing right atrial to pulmonary artery flow which unloaded the RV. The ratio of area of infarction (AI) to area at risk (AR) of the RV was determined by vital dye staining. Total lung water (TLW) was determined by gravimetric analysis and expressed as milliliters per kilogram body weight. Throughout the experiment animals in Group 1 had significantly higher RV systolic pressures. Pulmonary vascular resistance was increased significantly in Group 2 at 4 hr (318% of baseline vs 33%). Mean pulmonary artery pressure increased significantly in Group 2 from 9.4 +/- 0.9 mm Hg at baseline to 21.0 +/- 5.0 mm Hg at 4 hr. Group 2 animals had a decreased AI/AR ratio (19 +/- 3 vs 57 +/- 9) and increased TLW (20 +/- 3 vs 9 +/- 1). Lung biopsies in Group 2 revealed perivascular, peribronchial, and intraalveolar hemorrhages that were not present in Group 1. In conclusion, a roller pump RVAD limits RV infarction but produces pulmonary hypertension, increases pulmonary vascular resistance, and creates pulmonary edema and hemorrhage in the process.

Thromboxane synthetase inhibition reduces ventricular irritability after coronary occlusion and reperfusion.

Reperfusion of ischemic tissue is responsible for production of metabolites with deleterious local vascular effects. Thromboxane A2, a potent vasoconstrictor and platelet aggregator, has been implicated as a mediator of the "reperfusion injury." We studied the effect of an experimental thromboxane synthetase inhibitor, OKY-046, on coronary sinus thromboxane levels, ventricular irritability, myocardial contractility, infarct salvage, and histologic features of reperfusion. Sixteen sheep were randomized to OKY-046, 3 mg/kg, or saline vehicle before 3-hour occlusion and subsequent reperfusion of the left anterior descending artery. The OKY group demonstrated less ventricular irritability as measured by incidence of ventricular fibrillation and necessity for countershock to reverse tachyarrhythmias. Coronary sinus thromboxane levels were significantly lower in the OKY group compared with the control group. There is additional evidence to suggest that OKY increases infarct salvage and attenuates histologic features of microcirculatory damage.

Effect of total spinal anesthesia on arterial and venous responses to dopamine and dobutamine.

To test whether acute denervation alters the vascular effects of dopamine and dobutamine, we anesthetized 16 greyhounds and placed them on total cardiopulmonary bypass (CPB). Eight dogs received total spinal anesthesia before drug testing; eight dogs were tested in the absence of total spinal anesthesia. During dopamine and dobutamine infusions, venous capacitance [determined by the volume of the CPB venous reservoir (VR)] and mean arterial pressure (MAP) were monitored. The CPB pump flows remained constant throughout our studies. Every dog received six increasing doses of both drugs. In the absence of total spinal anesthesia, both dopamine and dobutamine increased VR (decreased venous capacitance) in a dose-dependent manner. Dobutamine decreased MAP in a dose-related fashion but dopamine had no significant effect on MAP. After total spinal anesthesia, both dopamine and dobutamine produced greater dose-related increases in VR (i.e., decreases in venous capacitance) than in the absence of spinal anesthesia. Dopamine increased MAP but dobutamine had no significant effect. These data demonstrate how dopamine and dobutamine differ in their effects on the arterial circulation in the presence or absence of spinal anesthesia. The acute denervation of spinal anesthesia altered venous and arterial dose-response relationships of both drugs. Finally, our study demonstrates the effectiveness of dobutamine and, perhaps even more so, dopamine as possible alternatives to ephedrine for the pharmacologic correction of the noncardiac circulatory sequelae of spinal anesthesia.

Augmentation of venous return by adrenergic agonists during spinal anesthesia.

To test the effectiveness of adrenergic agonists in correcting the vascular sequelae of spinal anesthesia, we used venous reservoir volume (RV) and mean arterial pressure (MAP) as indices of the changes in venous capacitance and arterial resistance produced by adrenergic agonists in dogs anesthetized with pentobarbital and undergoing cardiopulmonary bypass (CPB). A CPB-based technique was chosen both to prevent drug and reflex effects on the heart from influencing the results and to provide a convenient means by which to monitor venous capacitance. Total spinal anesthesia significantly decreased both RV and MAP relative to steady-state CPB values. Return of these hemodynamic alterations to baseline was attempted using pure alpha- and beta-adrenergic agonists, and a mixed adrenergic agonist (phenylephrine, isoproterenol, and ephedrine, respectively). Isoproterenol increased RV, but further decreased MAP. Phenylephrine increased MAP but not RV. Ephedrine increased both MAP and RV. We conclude that a mixed adrenergic agonist such as ephedrine more ideally corrects the noncardiac circulatory sequelae of spinal anesthesia than does either a pure alpha- or beta-adrenergic agonist.

Hemodynamic, metabolic, and morphological effects of cardiopulmonary bypass with a fluorocarbon priming solution.

Systemic perfusion, myocardial contractility, and morphological changes during and after cardiopulmonary bypass (CPB) were investigated in 22 greyhounds; Fluosol-DA 20% (FDA) and normal saline (NaCl) were compared as priming solutions for hypothermic (25 degrees C) CPB. Hemodynamic and oxygenation indices were similar in all groups. Animals with fluorocarbon primes had higher serum lactate concentrations (mean +/- standard error of the mean [SEM]) during CPB (NaCl 1.64 +/- 0.2, FDA 2.39 +/- 0.3, p less than 0.01), representing an increase over the control of 12% and 319% in the NaCl and FDA groups, respectively. After CPB, serum lactate concentration remained elevated in the FDA group, but it returned to the level of the control in the NaCl group (NaCl 1.49 +/- 0.5, FDA 2.29 +/- 1.1, p less than 0.01); increases over the control level were 7% and 302% in the NaCl and FDA groups, respectively. Myocardial contractility after CPB, expressed as dP/dt[40], was similar in the two experimental groups. Three weeks after CPB, a histological examination by light microscopy of multiple organs obtained from a separate group of 12 animals treated similarly was performed, demonstrating no significant morphological differences between animals primed with fluorocarbon or with saline. The results suggest that FDA is a satisfactory priming agent for hypothermic CPB. It adequately preserves myocardial function and causes no adverse morphological changes, but a persistent, as yet unexplained, elevation in serum lactate concentration occurs.

Inotropic response of the salvaged myocardium after acute coronary occlusion.

We determined the response of the reperfused myocardium to inotropic stimulation with dobutamine hydrochloride. The middle part of the left anterior descending coronary artery (LAD) was occluded in 15 greyhounds for 3 hours. Group 1 (N = 8) was reperfused for 3 hours in the beating, working heart. Group 2 (N = 7) was put on cardiopulmonary bypass (CPB) for 1 hour, received 500 ml of potassium cardioplegia in the aortic root and in the area of ischemia through an internal mammary-LAD graft, and the LAD was reperfused off CPB for 3 hours. After 3 hours of reperfusion, dobutamine was given at 10 micrograms/kg/min for 20 minutes. Regional myocardial function was determined with subendocardial ultrasonic crystals in the area of ischemia and in the base of the heart; segmental contractility was determined from the ratio of peak left ventricular pressure to end-systolic segment length; and global contractility was determined by the slope of the ventricular pressure wave at a developed pressure of 40 mm Hg. Measurements were made prior to LAD occlusion (control), at the end of 3 hours of reperfusion (6 hours from the beginning of occlusion), and after 20 minutes of dobutamine infusion. Dobutamine infusion improved segmental function in all animals compared with 3 hours of reperfusion. The study shows that the reperfused myocardium responds favorably to inotropic stimulation after 3 hours of occlusion and 3 hours of reperfusion, and that the contractile response both to reperfusion and to inotropic stimulation is greatly affected by the method of reperfusion.

Crowbar impalement of the brain.

The management of impaled foreign objects is always a challenge. Stabilization of the object, control of hemorrhage, and adherence to the basic principles of airway and breathing control are hallmarks of prehospital management. Once the patient is in the hospital, a careful assessment of the involved vital structures is essential before removal is attempted. A penetrating injury to the left hemisphere of the brain with a crowbar is presented. This case demonstrates the characteristics of these injuries in terms of extrication, assessment, management of complications, and neurologic sequelae.

Prehospital trauma care.

The past two decades have been a period of increased concern over the improvement of prehospital emergency medical care. Training of basic and advanced EMTs to a level of professionalism that includes a distinct body of knowledge and the use of assessment and management skills is only one component of the prehospital system. Communications systems, transportation deployment plans, and improved links with hospitals have contributed to the refinement of emergency medical systems. The management of the trauma victim is an organized plan of controlling the airway, restoring breathing, and supporting ventilation, followed by a secondary survey of the less life-threatening problems. The role of EMTs or paramedics, therefore, is to assess, manage, extricate, and transport.

Endotracheal intubation in the prehospital phase of emergency medical care.

One hundred seventy-eight endotracheal intubations by paramedics were reviewed prospectively during a nine-month period; 149 patients (83.7%) had medical conditions, and 29 (16.2%) had trauma. The endotracheal tube was successfully placed in 172 (96.6%); in four patients (2.2%), attempts were unsuccessful, and in two patients (1.1%), the attempt was aborted. There were no incidences of reported complications. We conclude that endotracheal intubation can be accomplished successfully outside the hospital by paramedical personnel. Comprehensive training and continuous medical control of paramedics' activities seem to be essential requirements for its success.