James T. Diehl

Transsternal Radical Thymectomy for Myasthenia Gravis: A 15-Year Review

Thymectomy is an accepted therapeutic modality for patients with myasthenia gravis. The selection of patients for operation and the surgical approach are controversial. We reviewed 52 patients (aged 18 months to 82 years; mean age, 34 years) treated with transsternal radical thymectomy between 1972 and 1987. Patients were symptomatically staged according to the modified Osserman classification. There was one hospital death and postoperative follow-up was obtained on 51 patients. Improvement after thymectomy was observed in 3 of 11 patients (27%) in Osserman stage I, 16 of 25 patients (64%) in Osserman stage IIA, and 13 of 15 patients (86%) in combined Osserman stages IIB, III, and IV. Preoperative Osserman stage, patient sex, and thymic histology correlated with postoperative clinical response. Transsternal radical thymectomy is effective therapy for myasthenia gravis. Sustained improvement is obtained in patients with moderate and advanced disease. The majority of patients with ocular disease do not benefit from operation.

Efficacy of Retrograde Coronary Sinus Cardioplegia in Patients Undergoing Myocardial Revascularization: A Prospective Randomized Trial

The efficacy of retrograde coronary sinus cardioplegia (RCSC) administered through the right atrium compared with aortic root cardioplegia (ARC) has not been examined critically in patients undergoing coronary artery bypass grafting (CABG). Twenty patients having elective CABG were randomized prospectively to receive cold blood ARC (Group I, 10 patients) or cold blood RCSC (Group II, 10 patients). Patient demographics were similar in both groups. Ventricular function was assessed preoperatively by radionuclide ventriculography and postoperatively by simultaneous hemodynamic and radionuclide ventriculographic studies with volume loading. There was no change in ejection fraction (EF) (preoperative versus postoperative value) in Group I (50 +/- 6% versus 53 +/- 6%) but in group II, at similar peak systolic pressure and similar left ventricular end-diastolic volume index (LVEDVI), LVEF improved significantly (49 +/- 6% versus 60 +/- 12%, p less than 0.05). Postoperative ventricular function (stroke work index versus EDVI) for the left ventricle and right ventricle were similar in both groups. Evaluation of postoperative LV systolic function (end-systolic blood pressure versus end-systolic volume index) and diastolic function (pulmonary capillary wedge pressure versus EDVI) were also similar in both groups. Retrograde coronary sinus cardioplegia is as effective as ARC for intraoperative myocardial protection, and provides excellent postoperative function in patients undergoing elective CABG.

Spinal cord protection during aortic occlusion: efficacy of intrathecal tetracaine.

Spinal cord ischemia and resultant paraplegia are devastating sequelae in up to 40% of patients undergoing repair of thoracoabdominal aneurysms. We investigated the effect of intrathecal tetracaine on the neurological sequelae of spinal cord ischemia and reperfusion with aortic occlusion. Cocaine-derived anesthetics (lidocaine and its analogues) have been shown to decrease neuronal cell metabolism and also have specific neuronal membrane stabilizing effects. New Zealand white rabbits were anesthetized and spinal cord ischemia was then induced by infrarenal aortic occlusion. Animals were divided into six treatment groups. Tetracaine (groups 2 and 4) or normal saline solution (group 5) was administered intrathecally before aortic cross-clamping. Groups 1 and 3 functioned as controls. Group 6 animals received intravenous thiopental. Rabbits were classified as either neurologically normal or injured (paralyzed or paretic). Among controls, 25 minutes of aortic occlusion produced varied neurological sequelae (group 1, 3/6 injured, 50%) whereas 30 minutes resulted in more consistent injury (group 3, 5/6 injured, 83%). All rabbits that received intrathecal saline solution were paralyzed (group 5, 4/4 injured, 100%). Animals treated with intrathecal tetracaine and aortic occlusion of 30 minutes (group 4) showed significantly better preservation of neurological function (6/7 normal, 86%) than controls and saline-treated animals (groups 3 and 5). All animals treated with intrathecal tetracaine and aortic occlusion for 25 minutes (group 2) showed no signs of injury (5/5 normal, 100%), but this was not significant versus controls (group 1). Intravenous thiopental (group 6, 5/5 injured, 100%) had no beneficial effect. Intrathecal tetracaine significantly and dramatically abrogated the neurological injury secondary to spinal cord ischemia and reperfusion after aortic occlusion at 30 minutes in the rabbit model.

Arterial Bypass of the Descending Thoracic Aorta with the BioMedicus Centrifugal Pump

Bypass of the descending thoracic aorta is frequently advocated as an adjunct for repair of traumatic tears and degenerative aneurysms. Many methods of bypass have been proposed to provide distal perfusion and reduce left ventricular afterload during cross-clamp of the thoracic aorta. We describe a simple method of direct arterial (aortoaortic or aortofemoral) bypass using the BioMedicus centrifugal pump with limited systemic heparinization.

Comparison of eurocollins and University of Wisconsin solution in single flush preservation of the ischemic reperfused lung : an in vivo rabbit model

The standard preservation technique in lung transplantation is cold single pulmonary artery flush (PAF) with Eurocollins solution (ECS). We compared ECS with University of Wisconsin (UW) solution, with and without added indomethacin, in single PAF preservation in an in vivo rabbit model of warm ischemiareperfusion lung injury. Six groups of four New Zealand white rabbits each underwent isolation and hilar stripping of the left lung. In the four experimental groups, the left lung was flushed with (15 ml/kg) of cold ECS or UW solution, with or without added indomethacin, before warm ischemia for 120 minutes and before reperfusion for 60 minutes. The remaining two groups were the nonischemic and the ischemic “no flush” controls. Transcapillary flux of 99mTechnitium-labeled albumin and electron microscopy were used to demonstrate lung injury. Pulmonary vascular resistance (PVR) and thromboxane B2 (TXB2) concentrations were measured. There was a significant rise in PVR after ischemia/ reperfusion in the ischemic control group (54.7±13.9 to 117.8±20.7 mm Hg/L-min-1, P<0.05). The net rise in PVR after ischemia-reperfusion was significantly smaller in the two groups in which indomethacin was added (16.8±17.5 and 4.5±10.6 mm Hg/L-min-1 for UW and ECS, respectively) compared with the ischemic control (63.1±24.6 mm Hg/L-min-1, P<0.05). Postreperfusion TXB2 levels tended to be lower in the nonischemic control group and in the indomethacin-flush groups. We conclude that the increase in PVR produced by unilateral ischemia-reperfusion lung injury in this model was improved by single PAF perfusion. There was no significant difference between UW solution and ECS in this regard. The addition of indomethacin to the flush solution was associated with lower PVRs as well as morphologic improvement by electron microscopy. These findings may indicate a prominent role for the provision of PG synthesis inhibition during preservation for lung transplantation.

Left ventricular diastolic collapse in regional left heart cardiac tamponade: An experimental echocardiographic and hemodynamic study☆

OBJECTIVES This study was designed to describe the hemodynamic abnormalities associated with the appearance of left ventricular diastolic collapse in the setting of regional left heart cardiac tamponade. BACKGROUND Cardiac tamponade after heart surgery is frequently associated with localized pericardial effusion. Although right ventricular diastolic collapse and right atrial collapse are reliable echocardiographic findings in patients with circumferential pericardial effusion and tamponade, they are often not present in postoperative patients with localized pericardial effusion and regional left heart tamponade. Left ventricular diastolic collapse has been described in such patients, but the degree of hemodynamic alteration that exists with this finding is not known. METHODS Acute regional left heart tamponade was produced 14 times in seven spontaneously breathing anesthetized dogs by infusing fluid into an isolated compartment created in the pericardial space adjacent to the left ventricular free wall. Continuous echocardiographic imaging and hemodynamic monitoring of left ventricular, systemic arterial, right atrial, pulmonary capillary wedge and pericardial pressures were performed. Measurements at baseline were compared with those made at the onset of left ventricular diastolic collapse and at decompensated tamponade. RESULTS Left ventricular diastolic collapse was noted in all 14 episodes of regional tamponade. It occurred when pressure in the left pericardial compartment exceeded left ventricular diastolic pressure by 3.0 +/- 1.9 mm Hg. At the onset of left ventricular diastolic collapse, cardiac output and mean arterial pressure were significantly reduced from the control value (p < 0.05). Systolic hypotension was noted only twice at this stage, respiratory variation in systolic pressure > 10 mm Hg only once. The appearance of this sign was also associated with elevated left heart filling pressures. CONCLUSIONS Left ventricular diastolic collapse is a reliable sign of regional left ventricular tamponade and is associated with a reduction in cardiac output. This echocardiographic finding usually occurs before the development of arterial hypotension and pulsus paradoxus. Thus, left ventricular diastolic collapse is potentially more reliable than hypotension or pulsus paradoxus in the diagnosis of regional left ventricular tamponade.

Protective effects of retrograde compared with antegrade cardioplegia on right ventricular systolic and diastolic function during coronary bypass surgery.

The effect of retrograde cardioplegia delivered through the right atrium on right ventricular performance has not been critically examined in humans. We randomized 20 patients with right coronary artery lesions to receive cold blood cardioplegia solution either retrograde through the right atrium (group 1, n = 10) or antegradely (group 2, n = 10). The patients were similar in age, sex, severity of coronary artery disease, cross-clamp time, and completeness of revascularization. Before operation, right ventricular function was assessed by radionuclide ventriculography, and 18-24 hours after operation, right ventricular volumes and performance were assessed at a constant-paced heart rate by simultaneous hemodynamic-radionuclide measurements, before and after a fluid challenge. Intraoperative right ventricular temperatures were not different between the groups. Right ventricular volumes and ejection fractions were not different at baseline. After operation, at similar heart rates and loading conditions, there was a trend for the antegrade group to increase right ventricular end-systolic volume (p less than 0.1) whereas the retrograde group had no change in this parameter from the preoperative state. Postoperative ventricular function curves (p = NS, retrograde versus antegrade) suggest equivalent systolic performance in both groups. Right ventricular diastolic performance showed no significant differences between the two groups, suggesting no detriment to compliance due to right ventricular distension during operation. This suggests that retrograde cardioplegia adequately protects the right ventricular myocardium during bypass surgery and may be used as an alternative procedure in situations where ventricular cooling is inadequate with antegrade delivery due to severe coronary artery disease or aortic valvular disease.

Computed tomography-guided minithoracotomy for the resection of small peripheral pulmonary nodules.

Small peripheral pulmonary nodules ranging in size from 1 mm to 20 mm were excised in 58 patients. Computed tomography was used to mark the skin overlying the nodules to minimize the surgical exposure needed for operative identification. The nodules were 1 cm or less in maximum diameter in 76% of the patients. Twenty-six patients had single nodules and 32 patients had multiple nodules. The preoperative diagnosis was inaccurate in 67% of the patients. In 61% of the patients in whom malignancy was suspected, no tumor was demonstrated. Conversely, of the 20 patients in whom a malignant nodule was excised, the preoperative diagnosis was correct in only 50%. Thirty-one patients required no further treatment apart from their biopsy and 27 required additional intervention. Small peripheral pulmonary nodules require biopsy for diagnosis. When percutaneous needle aspiration biopsy is unsuccessful, or technically difficult, a computed tomography-guided thoracotomy is an effective and minimally invasive surgical alternative.

Tracheoesophageal fistula associated with Barrett's ulcer: The importance of reflux control

A benign tracheoesophageal fistula occurring as a complication of Barretts ulcerative esophagitis is described. Surgical control of gastroesophageal reflux resulted in healing of the fistula, obviating the need for a resective procedure or esophageal exclusion. Although Barretts ulcer has been reported as a cause of acquired esophagorespiratory fistula, to our knowledge, the important role of reflux control in the management of this difficult problem has not been discussed.

Use of Self-Adhesive External Defibrillator Pads for Complex Cardiac Surgical Procedures

We describe a useful technique for the management of life-threatening arrhythmias that occur during complex or reoperative cardiac surgical procedures when internal defibrillation cannot be achieved. Two self-adhesive external pads are attached to the patient before draping to enable the delivery of current for defibrillation or cardioversion without the need for removal of adhesive surgical drapes and the cumbersome use of external defibrillator paddles.