Lawrence R. Glassman

Extracorporeal membrane oxygenation as an adjunct treatment for primary graft failure in adult lung transplant recipients.

Primary graft failure is a catastrophic event in lung transplantation. Failure is characterized by profound abnormalities of gas exchange that are frequently unresponsive to alterations in mechanical ventilation. This condition can be fatal and, if less severe, is usually associated with significant permanent damage to the allograft. We report the use of extracorporeal membrane oxygenation as a means to support lung transplant recipients with severe graft failure. Since 1991, extracorporeal membrane oxygenation has been used on 17 occasions for the temporary support of 16 adult lung transplant recipients. All patients met or exceeded standard National Institutes of Health guidelines for institution of extracorporeal membrane oxygenation. Nine double lung, six single lung, and one heart-lung recipients were supported for 1 to 12 days (mean 4.6 +/- 2.2 days). Extracorporeal membrane oxygenation was instituted early, within 7 days of transplantation, in ten patients. Eight early patients (80%) were successfully weaned from extracorporeal membrane oxygenation. Seven of ten (70%) patients were long-term survivors, and five of the seven had normal lung function. In comparison, there were no survivors among six recipients placed on extracorporeal membrane oxygenation for late (> or = 7 days) graft dysfunction. Extracorporeal membrane oxygenation is a lifesaving adjunct in recipients with acute graft failure after lung transplantation. Ischemia-reperfusion injury and acute graft dysfunction after lung transplantation can be successfully reversed with early aggressive intervention.

Perioperative Morbidity and Mortality in Combined vs. Staged Approaches to Carotid and Coronary Revascularization

Between 1986 and 1994 we identified 57 patients who underwent carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) during the same hospitalization. Simultaneous CABG and CEA was performed in 28 patients (mean age 70.5 years, 58% male). Indications for CABG in these patients were myocardial infarction in two, crescendo angina in 19, congestive heart failure in two and left main or triple-vessel coronary artery disease noted during carotid preoperative evaluation in five. Indications for CEA were transient ischemic attack (TIA) in 12, crescendo TIA in six, cerebrovascular accident (CVA) in five, and asymptomatic stenosis in five. There were no postoperative myocardial infarctions or perioperative deaths. Two patients developed atrial fibrillation, and four patients had CVAs (two were ipsilateral to the side of CEA). Twenty-nine patients underwent staged procedures (i.e., not performed concomitantly but during the same hospitalization). Indications for CABG and CEA were comparable to those in the group undergoing simultaneous procedures. In 17 patients CEA was performed before CABG. There was a single CVA, the result of an intracerebral hemorrhage. Five of the 17 patients had a myocardial infarction and two died; one patient had first-degree heart block requiring a pacemaker. Four additional patients developed atrial fibrillation, one of whom required cardioversion. The remaining 12 patients had CABG followed by CEA. There were no CVAs, myocardial infarctions, arrhythmias, or deaths in this subgroup. These data demonstrate that the performance of simultaneous CABG and CEA procedures is associated with increased neurologic morbidity (14.3%), both ipsilateral and contralateral to the side of carotid surgery in contrast to staged CABG and CEA (3.4%). In addition, when staged carotid surgery preceded coronary revascularization in those with severe coronary artery disease, the combined cardiac complication and mortality rate was significantly higher than when coronary revascularization preceded CEA. This evidence suggests that when CABG and CEA must be performed during the same hospitalization, the procedures should be staged with CABG preceding CEA.

Successful plication for postoperative diaphragmatic paralysis in an adult

Diaphragmatic paralysis developed in an adult after a cardiac operation. The patient suffered from recurrent fevers and could not be weaned from mechanical ventilatory support. Diaphragmatic plication was performed and enabled rapid and sustained weaning from respiratory support.

Continuous Measurement of Intramyocardial pH: Correlation to Functional Recovery Following Normothermic and Hypothermic Global Ischemia

The continuous measurement of intramyocardial pH was used to follow the progression of ischemia and was correlated to the recovery of left ventricular function following normothermic (38 degrees C) and hypothermic (25 degrees C) global ischemia. New miniature myocardial transducers, which incorporate fiberoptic technology and dual pH- and temperature-sensing capability, were placed into the left ventricular free wall and septum of 52 sheep undergoing cardiopulmonary bypass. Left ventricular stroke work as a function of mean left atrial pressure curves were generated before and after cardiopulmonary bypass by volume loading with whole blood. Functional recovery was determined by the ratio of the integrals of the preischemic and postischemic function curves. Control sheep (N = 11) did not undergo ischemia. Three groups (N = 41) underwent aortic cross-clamping until pH reached 7.0, 6.8, or 6.6. The preischemic myocardial pH averaged 7.42 +/- 0.01. Following both normothermic and hypothermic global ischemia, no significant difference was demonstrated in recovery of function between control (pH 7.4) and pH 7.0 groups at either temperature. However, recovery of function of the pH 6.8 and pH 6.6 groups was significantly decreased (p less than 0.01) versus control and pH 7.0 groups at both temperatures. No significant difference in recovery of function was demonstrated at any pH level when normothermic versus hypothermic groups were compared. However, hypothermia provided increased time (p less than 0.001) before each level of function was reached with a slower rate of change of pH (p less than 0.01) compared with the corresponding same pH group in sheep undergoing normothermic (38 degrees C) cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct-current injury from external pacemaker results in tissue electrolysis

Abstract In two patients undergoing open heart operations, electrochemical bums developed at the sites of connection to an external pacing system. Investigation revealed that failure of the pacing generator caused a small, continuous, direct current to pass through the patients, resulting in electrolysis at the sites of contact with the pacing and grounding wires. This electrolytic reaction was recreated in a mock pacing system and resulted in tissue injury and disintegration of the pacing wire. Guidelines to help recognize and prevent this complication are presented.

Continuous Measurement of Intramyocardial pH: Relative Importance of Hypothermia and Cardioplegic Perfusion Pressure and Temperature

The continuous measurement of intramyocardial pH was used to follow the progression of ischemia and permit correlation to functional recovery. Adequacy of myocardial preservation following 38 degrees C or 25 degrees C global ischemia alone or with the administration of one or two doses of 38 degrees C, 25 degrees C, or 1 degree C crystalloid cardioplegia at aortic root perfusion pressures of 90 mm Hg or 130 mm Hg was assessed. A new miniature myocardial transducer incorporating fiberoptic technology and dual pH and temperature-sensing capability was placed into the left ventricular free wall and septum of 44 sheep undergoing ischemic arrest during cardiopulmonary bypass. All groups underwent global ischemia until myocardial pH was 6.8. An intramyocardial pH level of 6.8 reliably correlated to similar levels of functional recovery in each group. Aortic root perfusion pressure of 130 mm Hg provided enhanced myocardial protection by increasing the total ischemic time (5 to 10 minutes) with one (p less than 0.01) or two (p less than 0.001) doses of cardioplegic solution until a given functional level of recovery was attained. Aortic root perfusion pressure of 90 mm Hg provided no added benefit in total ischemic time, rate of change of pH, or degree of recovery of function. Hypothermic (25 degrees C) global ischemia alone enhanced myocardial protection by providing increased time (p less than 0.01) until a given functional level of recovery was attained with a slower rate of change of pH (p less than 0.01) compared with normothermic (38 degrees C) global ischemia alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Impending Paradoxical Embolus

The diagnosis of paradoxical embolization typically requires evidence of acute systemic arterial occlusion, systemic venous thrombosis, and a pathway for the thromboembolus to bypass the pulmonary vasculature. However, even when all of these findings are present, they cumulatively represent only a “smoking gun” from which a diagnosis is inferred. It is rare that one captures the actual process of paradoxical embolization “red-handed.” These transthoracic and transesophageal echocardiographic images demonstrate a thrombus …

Acute Rejection after Cardiac Transplantation: Detection by Interstitial Myocardial pH

Intramyocardial pH was assessed as a potential marker for clinical evaluation and treatment of acute rejection following cardiac transplantation. Fifteen cats underwent forty operative procedures. Following intra-abdominal heterotopic heart transplantation, serial laparotomies were performed in the early (days 0 to 2), intermediate (days 5 to 7), and late (days 7 to 16) postoperative periods. Rejection was assessed by serial clinical examinations, ECG analyses, B-mode echocardiography, histological and ultrastructural analyses, and measurements of interstitial myocardial pH. Intramyocardial pH was measured by a new miniature (0.6 X 3.0 mm) fiberoptic pH transducer. At confirmed rejection, concomitant laparotomy and thoracotomy were performed and pH sensors were implanted in both native (anatomical) and graft hearts. Nine animals at rejection were given methylprednisolone and changes in graft and native heart pH were measured. The pH during absence of rejection, mild acute rejection, and severe acute rejection averaged 7.430 +/- 0.019, 7.233 +/- 0.040 (p less than .02), and 6.860 +/- 0.066 (p less than .02), respectively (mean +/- standard error of the mean). A progressive decline in pH was noted in each heart. In animals receiving steroids, graft heart pH increased over 90 minutes from 6.852 +/- 0.065 to 7.043 +/- 0.077 (p less than .05). Although pH decline may be secondary to either inflammatory or ischemic etiology, histological and ultrastructural analyses demonstrate a predominant inflammatory response with progressive mononuclear cell infiltration, interstitial edema, vascular wall edema, infiltration by polymorphonuclear neutrophil leukocytes, vacuolation of sarcoplasmic reticulum, and disarray of myocytes associated with falling pH. Degree of pH change correlated closely with degree of histological rejection, presence of ECG voltage decline, and change in wall thickness by ultrasound.