Long-term heart preservation by intermittent perfusion with crystalloid medium.

This study was undertaken to determine whether hearts preserved with intermittent coronary perfusion would recover physiologic function after a prolonged period of hypothermic preservation. Intermittent perfusion is commonly used for cardioplegia, but its efficacy in long-term heart preservation has not yet been demonstrated. Five groups of isolated rat hearts were studied (n = 7 per group): (1) fresh nonpreserved control hearts; (2) hearts preserved with continuous low-pressure perfusion via the aorta; (3) hearts preserved with cycles of 5 minutes of perfusion followed by 25 minutes of nonperfusion; (4) hearts preserved with cycles of 10 minutes of perfusion followed by 25 minutes of nonperfusion; (5) hearts preserved with submersion storage without perfusion. An oxygenated extracellular-type crystalloid medium (oxygen tension = 820 +/- 5 mm Hg) was used as a preservation medium; preservation was for 12 hours. During preservation, the coronary resistance of the intermittent perfusion-preserved hearts increased significantly, and these hearts produced significantly more excess lactate than did hearts in the other two preservation groups. The submersion-stored hearts exhibited no postpreservation ventricular function in an isolated perfused working rat heart system. The poststorage function of the other four groups, which was quantified during a 4-hour, 37 degrees C perfusion period at constant heart rate, indicated that there were no significant group differences with respect to output or energetics (coronary flow, aortic output, cardiac output, myocardial oxygen consumption, and external work efficiency). The intermittent perfusion-preserved hearts had significantly lower postpreservation contractile function (left ventricular systolic pressure, peak rates of left ventricular pressure development and relaxation, peak aortic flow rate, stroke work, and peak power) and higher left ventricular end-diastolic pressure compared with the control group. Although hearts preserved with intermittent perfusion had a loss of contractile function and decreased compliance compared with fresh hearts, after preservation they had better function than did hearts preserved with submersion storage and the same function as hearts preserved with continuous perfusion.

Poststernotomy fractures and pain management in open cardiac surgery.

STUDY OBJECTIVES: To assess whether (1) there is an increased incidence of sternal fractures associated with internal mammary artery (IMA) revascularization in open heart surgery and (2) there is a higher incidence of pain in postoperative patients with sternal fractures. METHODS: Two hundred eighty-eight consecutive adult patients who had undergone cardiac surgery underwent median sternotomy from 1989 to 1991. IMA revascularization was used in 94 patients. The remainder underwent conventional saphenous vein graft (SVG) revascularization or other open cardiac procedure. The sternum was checked for fracture at the time of chest-wall closure. Lung volumes, arterial blood gases, respiratory rate, and oxygen requirements were measured before and after pain relief by intravenous or epidural analgesia. RESULTS: Of 288 consecutive median sternotomies, there were a total of 24 sternal fractures. IMA harvesting was associated with a significantly greater incidence of sternal fractures. In the 94 patients in whom IMA mobilization was used, there were 16 fractures; in the remaining 194 cases, there were 8 fractures (p < 0.007). Twenty-one of 24 patients were not seriously affected by their sternal fractures, whereas 3 patients suffered major respiratory compromise due to postoperative pain. Epidural analgesia was effective treatment for these three cases of severe sternal fracture pain and was not associated with any adverse consequences. All three patients had significant improvement in their respiratory condition after epidural analgesia was instituted. Respiratory rate decreased from 27 +/- 3 to 18 +/- 0.3 breaths/min (p < 0.001) and end maximum inspired volume increased from 700 +/- 1 mL to 1,525 +/- 275 mL. CONCLUSIONS: The use of sternal retraction devices for IMA harvesting in coronary bypass procedures results in an increased incidence of sternal fractures when compared with conventional SVG bypass procedures. Although most sternal fractures are well tolerated, some patients with fractures can become a significant pain management problems. Epidural analgesia is a safe and effective treatment for severe pain associated with sternal fractures and provided improved postoperative pulmonary function.

Iatrogenic myocardial edema with potassium cardioplegia.

Postischemic myocardial edema depresses left ventricular function and coronary perfusion. Pharmacologic cardioplegia is being used increasingly to enhance myocardial protection during cardiac operations. In the present study we varied the colloid osmotic and osmotic pressures and the infusion pressures of four cardioplegic solutions to determine their respective roles in producing or preventing myocardial edema in a nonischemic setting. We found that myocardial edema during potassium cardioplegia (1) is independent of infusion pressures, (2) is caused by isosmotic crystalloid solutions, (3) is worsened by hyposmolar crystalloid solutions, (4) is avoided by the addition of colloid, and (5) is avoided if the solution is made hyperosmotic with the addition of mannitol.

Critical importance of ensuring cardioplegic delivery with coronary stenoses.

This study examines the relative importance of the duration of ischemia versus the adequacy of cardioplegic distribution and protection in hearts with coronary stenoses. Of 18 dogs on cardiopulmonary bypass, 12 underwent critical narrowing (greater than 90%) of the left circumflex artery (LCA) and total occlusion of the anterior descending coronary artery (LAD). In six dogs (control) the coronary arteries were patent. A 16 degrees C blood cardioplegic solution was given at 20 minute intervals of aortic clamping. In control dogs and in six dogs with stenoses, the aorta was clamped for 60 minutes. In the latter group, the stenoses were removed after 20 and 40 minutes to simulate sequential completion of grafts and better cardioplegic distribution. In the remaining dogs with stenoses, the aorta was clamped for only 30 minutes, with stenoses removed after the heart had been returned to the beating empty state for 30 minutes to simulate doing distal grafts with cardioplegic protection and proximal grafts during reperfusion (traditional technique). With sequential grafting, myocardial temperature was lower (16 degrees C versus 22 degrees C) and incidence of reperfusion fibrillation less than with the traditional technique. Despite a greater ischemic interval, sequential grafting with adequate cardioplegic distribution resulted in less lactate washout (5 +/- 15 versus 35 +/- 6 cc/100 gm/min), greater recovery of compliance, and higher stroke work indices (1.32 +/- 0.12 versus 0.75 +/- 0.15 kg-m/min). We conclude that the success of myocardial protection with potassium cardioplegia in hearts with coronary stenoses is related more to ensuring its distribution than to limiting the duration of ischemic arrest with the false assumption that the heart is reperfused adequately while proximal grafts are completed in the beating empty state.

Optimizing myocardial supply/demand balance with alpha-adrenergic drugs during cardiopulmonary resuscitation.

In 14 dogs the determinants of myocardial blood supply and metabolic demands were assessed during cardiopulmonary resuscitation (CPR) and under steady-state conditions in fibrillating hearts on cardiopulmonary bypass. During open chest cardiac massage (nine dogs), coronary diastolic blood pressure and blood flow were low. Vasopressor infusion (methoxamine or epinephrine) raised diastolic pressure from 33 +/- 3 to 55 +/- 3 mm. Hg and increased coronary blood flow (CBF) 124 percent (from 38 +/- 3 to 85 +/- 11 c.c. per 100 Gm. per minute. Comparison of these drugs in fibrillating hearts on cardiopulmonary bypass showed that epinephrine increased the "vigor of fibrillation" (intraventricular balloon pressure rose 24 percent and oxygen uptake increased 42%) but impeded subendocardial flow 53% (endocardial/epicardial flow ratio fell from 0.79 to 0.48). In contrast, methoxamine did not significantly change intraventricular balloon pressure, oxygen uptake, coronary flow, or its distribution. We conclude that augmentation of diastolic pressure with alpha adrenergic drugs during CPR improves coronary perfusion and that inotropic drugs may worsen myocardial ischemia during CPR by raising oxygen demands while simultaneously impeding subendocardial blood supply.

Reducing postischemic damage by temporary modification of reperfusate calcium, potassium, pH, and osmolarity.

This study was designed to determine if ischemic damage could be reduced by modifying blood composition upon reperfusion. After control data had been obtained in seven dogs on prolonged cardiopulmonary bypass, 71 dogs underwent 1 hour of ischemic arrest with topical hypothermia (left ventricular temperature 16 degrees C). We measured left ventricular performance (isovolumetric function curves), compliance (intraventricular balloon), blood flow (microspheres), metabolism (oxygen consumption), and water content (wet/dry weights) before and 30 minutes after ischemia. The initial reperfusate was 500 cc of oxygenated blood given over a period of 5 minutes. Without temporary reperfusate modification, postischemic left ventricular performance was depressed 40% +/- 3%, compliance fell 50% +/- 12%, water content rose 2.5% +/- 0.1%, and left ventricular blood flow and oxygen uptake increased only minimally when cardiac work was increased (function curve). These deleterious changes were reduced significantly, but not prevented, by the following isolated reperfusate modifications: (1) lowering amount of ionic calcium available for cell entry, (2) raising pH to 7.8 to counteract acidosis, (3) raising potassium level to maintain arrest and reduce metabolic demands, and (4) increasing osmolarity (mannitol, 360 mOsm) to counteract edema. In contrast, by combining these modifications to achieve a hypocalcemic, hyperkalemic, alkalotic, and hyperosmolar blood perfusate, it was possible to attain 104% +/- 1% recovery of myocardial performance, 80% +/- 1% restoration of compliance, 60% less postischemic edema, and near-normal augmentation of left ventricular flow and oxygen uptake to meet increasing needs.

Thymectomy in the treatment of ocular myasthenia gravis.

BACKGROUND: Thymectomy is an effective and accepted treatment for myasthenia gravis, but thymectomy for ocular myasthenia gravis (Osserman stage I) is controversial. OBJECTIVE: To assess the efficacy and propriety of thymectomy for the treatment of ocular myasthenia gravis. METHODS: We conducted a review and follow-up of all patients who had thymectomy for the treatment of ocular myasthenia gravis between 1970 and 1998 at the University of California, Davis, Medical Center, and the University of Rome, "La Sapienza," Rome, Italy. Patient response to thymectomy was categorized as follows: cured, patients who became symptom-free and required no further medication; improved, patients who required less medication and whose symptoms were less severe; unchanged, patients whose symptoms and medications were the same; worse, patients who had more severe symptoms, needed more medication, or died. RESULTS: Sixty-one patients (mean age 37 years; range 14-73 years) were followed up for a mean duration of 9 years (range 0.5-29 years). Ocular myasthenia gravis with mixed and cortical thymomas, stages I to IV, occurred in 12 patients, and ocular myasthenia without thymomas occurred in 49 patients. Transsternal thymectomy (n = 55) and transcervical thymectomy (n = 6) resulted in cure in 31 (51%) patients, improvement in 12 (20%) patients, no change in 16 (26%) patients, and worsening of symptoms (including 1 postoperative death) in 2 patients. Patient outcomes were statistically independent of the duration of preoperative symptoms (mean 9.5 months), patient age, or the presence or absence of thymoma. In patients with ocular myasthenia, 70% were cured or improved after thymectomy; in the subgroup of patients with ocular myasthenia and thymoma, 67% were cured or improved. CONCLUSION: Thymectomy is an effective and safe treatment for patients with ocular myasthenia gravis.

Cardiac function and glycogen content after twenty-four-hour preservation with various metabolic substrates.

BACKGROUND: Previous work has suggested that recovery of cardiac function after long preservation periods is improved if a suitable exogenous substrate is provided. However, interpretation of existing data on the benefit of added substrate is complicated by differing preservation media and protocols studied, as well as differing models used to evaluate postpreservation recovery. These experiments were designed to evaluate glucose, pyruvate, aspartate, and glutamate as exogenous substrates for prolonged perfusion preservation of hearts with a rat heart model preserved with crystalloid medium and with function quantified in an isolated working heart preparation. METHODS: Cardiac function (n = 5/group) and tissue glycogen content (n = 5/group) were measured in fresh control rat hearts and four groups of hearts preserved for 24 hours in an extracellular-type cardioplegic medium containing 11 mmol/L glucose and either 20 mmol/L sodium aspartate, 20 mmol/L sodium glutamate, 20 mmol/L sodium pyruvate, or no other substrate. Postpreservation cardiac function was measured in an isolated working rat heart preparation for a 4-hour reperfusion period. Exogenous substrate consumption during preservation and tissue glycogen content at the end of preservation were measured with spectrophotometric assays. RESULTS: All hearts in the aspartate- and glutamate-preserved groups functioned for the full 4-hour period with stroke work that was 50% to 60% of control. Hearts preserved with only glucose substrate had inconsistent recovery: two of five hearts in that group did not recover, whereas three recovered similar to the aspartate and glutamate groups. None of the pyruvate-preserved hearts recovered contractile function. There was no association between postpreservation tissue glycogen content and extent of cardiac function recovery. CONCLUSION: Aspartate or glutamate plus glucose was the best substrate mixture among those tested for long-term perfusion preservation of hearts. These amino acids offer advantages over pyruvate because they produced better recovery of the hearts and because they are chemically more stable than pyruvate. Aspartate or glutamate plus glucose also produced better postpreservation function compared with glucose alone.

Cardiopulmonary bypass used in the resuscitation of eventual organ donors: a case report.

Little has been published regarding cardiopulmonary bypass in the resuscitation of eventual organ donors. One such pediatric donor at our institution provided organs, which have thus far been successful. Pediatric organs have demonstrated usefulness, even when transplanted into adult recipients. Further research will provide data on the utility of organs obtained after cardiopulmonary bypass resuscitation.

Improved oxygenation and increased lung donor recovery with high-dose steroid administration after brain death.

BACKGROUND: The number of patients waiting lung transplantation greatly exceeds the supply of donors. This study was conducted to determine the effect of high-dose steroid administration on oxygenation and donor lung recovery after brain death. METHODS: A retrospective analysis was conducted on 118 consecutive organ donors from January 1 through December 31, 1995. Eighty donors received high-dose steroids (methylprednisolone, mean 14.5+/-0.06 mg/kg) after organ procurement organization management began; a second group was composed of 38 patients who received no steroids. PaO2/FiO2 ratios were used to evaluate oxygenation. The number of single and double lungs transplanted served as the endpoint. RESULTS: No differences were noted in hemodynamics, most clinical or demographic variables and initial values of PaO2/FiO2 between groups. However, nonsteroid-treated donors showed an overall decrease in oxygenation (mean decrease in PaO2/FiO2 -34.2+/-14), whereas steroid-treated donors had a significant and progressive increase in oxygenation (mean increase in PaO2/FiO2: 16+/-14) before aortic cross-clamping (p = 0.01). Time before cross-clamping was longer in the steroid-treated patients (p = 0.003). The number of procured lungs was markedly greater in steroid-treated than nonsteroid-treated donors (25/80 patients vs 3/38; p < 0.01). CONCLUSIONS: High-dose methylprednisolone given during donor management results in improved oxygenation at organ recovery. This treatment resulted in a significant increase in the number of lungs transplanted and may have enabled donors to be treated longer.

Recovery of sheep hearts after perfusion preservation or static storage with crystalloid media.

BACKGROUND: These experiments were designed to evaluate the viability of large hearts after preservation by use of procedures that have shown good results with small animal hearts. Efficacy of novel long-term preservation protocols should be documented with a large animal model before such procedures can be adopted for clinical use. We studied the recovery of sheep hearts that were perfusion-preserved in media containing two different substrate mixtures and hearts stored without perfusion either in University of Wisconsin solution modified to maintain tissue adenosine triphosphate content or in Stanford solution. METHODS: Six groups of sheep hearts were studied: I, fresh nonpreserved controls; II, hearts perfusion-preserved at 11 degrees C for 24 hours by use of an oxygenated extracellular-type medium with pyruvate + glucose substrate; III, hearts preserved as for II but with aspartate + glutamate + glucose substrate; IV, hearts stored without perfusion at 3 degrees C for 24 hours in University of Wisconsin solution containing 2,3-butanedione monoxime 30 mmol/L, CaCl2 1 mmol/L, and fresh reduced glutathione 3 mmol/L; V, hearts stored without perfusion at 3 degrees C for 4 hours in Stanford solution; VI, hearts preserved as for II but without perfusion. Recovery was measured for 6 hours in a Langendorff model, perfused with an erythrocyte + albumin medium. RESULTS: Hearts that were perfusion-preserved with both substrate mixtures and hearts stored in modified University of Wisconsin solution recovered function that was not significantly different from control subjects. Hearts stored in Stanford medium did not recover as well as did groups II, III, and IV. Left ventricular pressure and peak rate of left ventricular relaxation of the Stanford group were lower, and left ventricular enddiastolic pressure was higher, than those values for controls (repeated measures analysis of variance; Dunnett's procedure). The group VI hearts did not recover function at all. CONCLUSION: The results suggest that large hearts preserved with medium containing either aspartate + glutamate + glucose or pyruvate + glucose have comparable recovery after long-term perfusion preservation. Aspartate + glutamate may offer advantages for clinical use because of their lower production of lactate and better chemical stability compared with pyruvate. Static storage in modified University of Wisconsin solution also produced viable hearts with recovery comparable to perfusion-preserved aspartate + glutamate + glucose hearts. Tests of these preservation media and procedures with large transplanted hearts are warranted.

Incomplete recovery of working heart function after twenty-four-hour preservation with a modified University of Wisconsin solution.

BACKGROUND AND METHODS: This study was designed to determine the function of isolated rabbit hearts after static preservation with modified University of Wisconsin solution for 24 hours. Commercially available University of Wisconsin solution, modified with CaCl2 1 mmol/L and 2,3-butanedione monoxime 30 mmol/L, was used as the preservative. After flushing the coronary vasculature with medium, hearts were submersion stored at 1 degree C to 4 degrees C. After preservation, isolated heart function at 37 degrees C was quantified for 30 minutes in a non-ejecting mode and for 4 hours ejecting at a physiologic workload. Fresh control hearts (n = 5) and University of Wisconsin solution-preserved hearts (n = 6) were studied. RESULTS: Nonworking (non-ejecting) left ventricular function of the two groups did not differ, except for peak rate of left ventricular pressure development which was higher for the University of Wisconsin solution hearts than for controls. When the hearts were subjected to a physiologic workload, however, left ventricular function of the two groups differed significantly. Three of the six University of Wisconsin solution hearts failed before the 4-hour perfusion end point, whereas all five control hearts maintained stable working function for the full 4 hours. The University of Wisconsin solution hearts, while in the ejecting mode, exhibited significantly impaired function. Mean values were as follows (p < 0.05): left ventricular systolic pressure (in millimeters of mercury), control 105 +/- 1, University of Wisconsin solution 86 +/- 4; peak rate of left ventricular pressure development (in millimeters of mercury per millisecond), control 3.33 +/- 0.11, University of Wisconsin solution 2.39 +/- 0.24; cardiac output (in milliliters per minute per gram), control 400 +/- 25, University of Wisconsin solution 288 +/- 26; stroke work (in milliJoules per gram), control 20.1 +/- 1.3, University of Wisconsin solution 11.9 +/- 1.1; left ventricular end-diastolic pressure (in millimeters of mercury), control 5.4 +/- 0.3, University of Wisconsin solution 10.2 +/- 1.3; peak aortic flow rate (in milliliters per minute), control 946 +/- 9, University of Wisconsin solution 659 +/- 44; millimoles of lactate produced in 30 min/Joule stroke work, control 0.50 +/- 0.06, University of Wisconsin solution 6.99 +/- 0.37. CONCLUSIONS: These results indicate that (1) hypothermic storage in this modified University of Wisconsin solution does not preserve hearts sufficiently to support a physiologic workload for an extended period and (2) assessment of post-preservation function with a non-ejecting heart model does not accurately predict the ability of the preserved heart to support a physiologic workload.

Steroid pretreatment improves graft recovery in a sheep orthotopic heart transplantation model.

BACKGROUND: Previous reports provide conflicting evidence concerning effects of steroids on recovery of cardiac function during procedures involving cardiopulmonary bypass. This study was designed to test the hypothesis that pretreatment of animals with steroids before heart transplantation improves graft hemodynamic function. METHODS: Four groups of sheep were studied: CON, nonsteroid-treated nontransplanted controls (n = 8); CON-S, steroid-treated nontransplanted controls (n = 5); TX, nonsteroid-treated transplanted animals (n = 5); and TX-S, steroid-treated transplanted animals (n = 5). Steroid-treated animals were given methylprednisolone 30 mg/kg immediately before surgery. Procedures for harvest and orthotopic transplantation were similar to those used clinically. Contractile function, left ventricular diameter, and cardiac output of control and transplanted hearts were measured for 6 hours. A 2 x 2 factorial repeated measures analysis of variance was used to determine statistical significance (p < 0.05). RESULTS: Steroid pretreatment produced significantly higher function in controls and transplanted animals compared with nonsteroid-treated animals. On average over 6 hours, significant steroid effects were observed for left ventricular peak systolic pressure, mm Hg (CON, 85 +/- 2; CON-S, 98 +/- 3; TX, 74 +/- 3; TX-S, 91 +/- 2); global stroke work, mJoule x cm(-2) (CON, 4.69 +/- 0.21; CON-S, 5.88 +/- 0.32; TX, 2.27 +/- 0.17; TX-S, 4.23 +/- 0.16); and peak rate of pressure relaxation (-dP/dt(max)), mm Hg/msec (CON, 1.23 +/- 0.05; CON-S, 1.44 +/- 0.08; TX, 0.60 +/- 0.03; TX-S, 2.04 +/- 0.13). Steroid pretreatment produced more stable recovery for transplanted animals. All five TX-S animals could be removed from inotropic support and had stable function for 6 hours. In contrast, 1 of 5 TX animals could not be removed from inotropic support, and 1 of 5 TX hearts failed 3 hours after transplant. Arterial blood PO2 values were significantly higher in steroid-treated animals than in nonsteroid treated animals. Blood systemic lactate, which was elevated after transplantation, returned to control level by 6 hours in the steroid-treated group but not in the nonsteroid-treated group. CONCLUSION: Steroid pretreatment of heart donors and recipients improved systolic and diastolic function and hemodynamic stability after transplantation. In addition, steroid pretreatment improved pulmonary gas exchange of control and transplanted animals.

Posttransplantation function of hearts preserved with fluorochemical emulsion.

This study was designed to determine whether the novel perfluoroperhydrophenanthrene-egg yolk phospholipid emulsion, APE-LM, was an effective oxygen carrier for long-term hypothermic heart preservation. We postulated that hearts preserved with APE-LM would be well oxygenated during 24-hour preservation and that reperfusion of such hearts with blood would not produce functional or metabolic evidence of myocardial ischemia. Four groups of rabbit hearts were studied (n = 7 per group): fresh controls: nonpreserved, nontransplanted hearts; surgical controls: fresh hearts transplanted heterotopically for 75 minutes before explant and study for 4 hours as isolated working hearts perfused at 37 degrees C; crystalloid-preserved: hearts preserved with crystalloid medium, followed by transplantation and isolated heart perfusion; APE-LM-preserved: hearts treated as those in the crystalloid-preserved group, but preservation was with medium containing APE-LM emulsion (10 ml/dl). Preservation was with continuous coronary perfusion at 18 mm Hg pressure, 12 degrees C, and oxygen tension 838 +/- 11 mm Hg. During preservation, APE-LM hearts had significantly higher pyruvate consumption, and correspondingly higher oxygen consumption, than that of crystalloid hearts. No significant differences were found among fresh controls, surgical controls, and APE-LM-preserved hearts with respect to contractile or output function, oxygen consumption and efficiency indexes, or lactate production during in vitro perfusion. Left ventricular peak systolic pressure and peak rate of pressure development were significantly lower for crystalloid-preserved hearts than for fresh and surgical controls. Left ventricular end-diastolic pressure of crystalloid-preserved hearts was higher than that of the other three groups. The data indicate that rabbit hearts in this model were well preserved with APE-LM and that this emulsion produced better recovery of function than did crystalloid preservation, possibly as a consequence of the high oxygen delivery by the fluorocarbon during preservation.

Importance of substrate enhancement for long-term heart preservation.

These experiments tested the hypothesis that addition of pyruvate to a preservation medium would improve postpreservation cardiac function as quantified in an isolated working heart model after heterotopic transplantation. Four groups of rabbit hearts were studied (n = 5 per group): fresh controls, fresh hearts perfused as isolated working hearts; surgical controls, fresh hearts transplanted heterotopically and reperfused with blood for 75 minutes before being studied as isolated hearts; preserved without pyruvate, hearts perfusion-preserved with oxygenated extracellular-type crystalloid medium; preserved with pyruvate, same same as the group without pyruvate, but medium contained 20 mmol/L pyruvate. After preservation, the hearts in the two preserved groups were transplanted and studied as isolated hearts. Total ex vivo time for the preserved hearts was 24.5 +/- 0.2 hours. During preservation, glucose was not consumed by hearts in either preserved group. Pyruvate was used by the hearts to which it was provided (22.9 +/- 2.7 mumol pyruvate x hour-1 x gm dry weight-1). Performance of transplanted surgical control hearts was not significantly different from that of fresh controls. Function of the pyruvate-preserved hearts was similar to that of the fresh and surgical controls except that left ventricular peak systolic pressure and peak rate of pressure development were lower and that left ventricular end-diastolic pressure was higher for the pyruvate-preserved hearts. The hearts preserved without pyruvate had significantly lower compliance and function compared to the other three groups, which was evident in all indexes of contractility and output. We conclude that hearts preserved with pyruvate-containing crystalloid medium had better postpreservation, posttransplantation function than hearts preserved without pyruvate, although there was slight loss of compliance and decreased contractile function in the pyruvate-preserved hearts compared to controls.

Improved myocardial function using cardiopulmonary support in resuscitation for hemorrhagic shock.

OBJECTIVES: To clarify the pathophysiologic characteristics of hemorrhagic shock and to assess methods of resuscitation. DESIGN: An animal experiment using sheep subjected to hemorrhagic shock and fibrillation to compare various resuscitation techniques. SETTING: An experimental laboratory setting meant to simulate hemorrhagic shock secondary to trauma. STUDY GROUPS: Group 1 animals (n = 6) were controls that were not subjected to shock and fibrillation. Group 2 animals (n = 6) were subjected to shock and fibrillation and were resuscitated with volume replacement. Group 3 animals (n = 6) were also subjected to shock and fibrillation but were resuscitated with epinephrine hydrochloride infusion. Group 4 animals (n = 6) were subjected to shock and fibrillation but were resuscitated with cardiopulmonary support. INTERVENTIONS: The shock was to a mean arterial pressure of 25 mm Hg for 1 hour followed by 5 minutes of fibrillation. Group 2 animals were resuscitated for 1 hour. Group 3 animals were supported for 6 hours on epinephrine after the shock period. Group 4 animals were supported for 1 hour on cardiopulmonary support, then were observed for another 5 hours. All animals were sedated and intubated, and a median sternotomy was performed. MAIN OUTCOMES MEASURED: Survival, hemodynamic function, lactate production, myocardial blood flow, and water content. RESULTS: Group 1 sheep showed no detrimental effects in any of the measured variables. Group 2 sheep could not be resuscitated. Group 3 sheep could be supported with epinephrine but had a 60% depression in left ventricular function and an ultimately high mortality rate (67%) when the infusion of epinephrine was discontinued. Group 4 sheep had a 100% survival rate and only a 20% deterioration in left ventricular function. CONCLUSIONS: Cardiopulmonary support improves survival and preserves left ventricular function compared with volume resuscitation with or without inotropic support in this model of hemorrhagic shock.

Use of cardiopulmonary bypass to salvage patients with multiple-chamber heart wounds.

BACKGROUND: The need for cardiopulmonary bypass in the treatment of penetrating heart injuries is debated. OBJECTIVES: To review our experience with penetrating heart injuries and determine the indications and outcome for cardiopulmonary bypass. DESIGN: Retrospective review. SETTING: A university-based, level I trauma center. PATIENTS: All victims of penetrating heart injury presenting between July 1, 1989, and December 31, 1995. METHODS: Medical records were reviewed for demographic and physiological data, operative findings, and outcome. RESULTS: Overall survival for 106 patients with penetrating heart injury was 55%. In an effort to resuscitate the heart, 4 patients with unresponsive cardiogenic shock were placed on cardiopulmonary bypass; none survived. Of 30 patients with multiple-chamber injuries, 11 presented with signs of life and 7 survived. Cardiopulmonary bypass was essential to repair complex injuries in 2 of the 7 survivors. CONCLUSION: Cardiopulmonary bypass was ineffective in salvaging patients with cardiogenic shock but was essential in some patients with complex multiple-chamber cardiac injuries that could not be exposed and repaired by other means.

Use of Carmeda-coated femoral-femoral bypass during repair of traumatic aortic pseudoaneurysms.

OBJECTIVE: To compare the results and outcomes of three different approaches to posttraumatic pseudoaneurysm repair: clamp and sew, left heart bypass, and the most recent approach, cardiopulmonary support using femoral-femoral bypass. DESIGN: Retrospective series. SETTING: A university-based, level 1 trauma center. PATIENTS: Forty-two consecutive patients treated for posttraumatic aortic pseudoaneurysm whose mean (+/- SEM) Injury Severity Score was 37 +/- 1.7. INTERVENTION: Methods of repair included clamp and sew in nine patients, left heart bypass in 24 patients, and cardiopulmonary support in nine patients. METHODS: Student's t test was used to compare interoperative blood loss, need for blood transfusion, and aortic cross-clamp time. Complications and mortality were also reviewed. RESULTS: Mean (+/- SEM) aortic cross-clamp time for clamp and sew was 28.1 +/- 3.3 minutes vs 52.5 +/- 3.7 for left heart bypass and 49.3 +/- 5.6 for cardiopulmonary support. Blood loss and the need for transfusion were comparable between groups. Complications were also comparable. CONCLUSION: Femoral-femoral cardiopulmonary support is safe to use, has a very low risk of complications, and should provide protection for the spinal cord during aortic repair. We encourage a randomized prospective trial to determine if cardiopulmonary support has a significantly lower rate of paraplegia than the clamp- and -sew technique.

Comparison of minimally invasive esophagectomy with transthoracic and transhiatal esophagectomy.

HYPOTHESIS: Minimally invasive esophagectomy can be performed as safely as conventional esophagectomy and has distinct perioperative outcome advantages. DESIGN: A retrospective comparison of 3 methods of esophagectomy: minimally invasive, transthoracic, and blunt transhiatal. SETTING: University medical center. PATIENTS: Eighteen consecutive patients underwent combined thoracoscopic and laparoscopic esophagectomy from October 9, 1998, through January 19, 2000. These patients were compared with 16 patients who underwent transthoracic esophagectomy and 20 patients who underwent blunt transhiatal esophagectomy from June 1, 1993, through August 5, 1998. MAIN OUTCOME MEASURES: Operative time, amount of blood loss, number of operative transfusions, length of intensive care and hospital stays, complications, and mortality. RESULTS: Patients who had minimally invasive esophagectomy had shorter operative times, less blood loss, fewer transfusions, and shortened intensive care unit and hospital courses than patients who underwent transthoracic or blunt transhiatal esophagectomy. There was no significant difference in the incidence of anastomotic leak or respiratory complications among the 3 groups. CONCLUSION: Minimally invasive esophagectomy is safe and provides clinical advantages compared with transthoracic and blunt transhiatal esophagectomy.

Giant carcinoid tumor of the lung.

A case of a giant atypical carcinoid tumor is discussed. The tumor occurred in a 33-year-old man who presented with pleuritic chest pain and shortness of breath. Details of his preoperative evaluation, metastatic work-up, and use of tumor embolization are described. The operative procedure and use of cardiopulmonary support to achieve appropriate margins are described as well. Review of the literature and pathologic characteristics of carcinoid tumors and atypical carcinoid tumors are discussed.