Cardiovascular effects of microgravity: evolution of understanding.

The understanding of cardiovascular effects of spaceflight has evolved throughout the course of the American manned spaceflight program. Originally descriptive in nature, the present understanding is based on empiric measurements of vascular volume, cardiac output, vascular reflexes, and peripheral and central autonomic control. More detailed understanding of cardiovascular effects has allowed us to separate those symptoms from symptoms caused by musculoskeletal or neurovestibular abnormalities.

Extracorporeal membrane oxygenation for early graft dysfunction in lung transplantation: a case report.

Although extracorporeal membrane oxygenation (ECMO) has become standard treatment for neonatal respiratory failure, the results of ECMO in adults have been less encouraging. With technical improvements in membrane oxygenators and revised ECMO protocols, there has been renewed interest in ECMO for adults with severe acute respiratory failure. However, few cases of ECMO as an adjunct to adult lung transplantation have been reported. We present the case of a 20-year-old woman with cystic fibrosis who underwent bilateral single lung transplantation. She had development of severe graft dysfunction in the immediate postoperative period requiring support with ECMO for stabilization.

Bio-Medicus centrifugal ventricular support for postcardiotomy cardiac failure: a review of 129 cases.

BACKGROUND: Bio-Medicus centrifugal ventricular support has been used widely for postcardiotomy cardiac failure. The purpose of this study was to review a large series of support patients examining complications and outcomes. METHODS: One hundred twenty-nine patients undergoing cardiac operations at The Methodist Hospital in Houston, Texas, were placed on Bio-Medicus centrifugal ventricular support for postcardiotomy cardiac failure; 102 were male and 27 were female with a mean age of 61.6 years. These patients were selected for ventricular support based solely on failure to be weaned from cardiopulmonary bypass or progressive postcardiotomy cardiac failure shortly after arrival in the intensive care unit. RESULTS: These patients experienced numerous complications including coagulopathy, renal insufficiency or failure, sepsis, neurologic deficits, ventricular failure, arrhythmias, and death; 56.3% of patients were weaned from mechanical support and 21.0% were discharged alive. Causes of death included ventricular failure (62.4%), arrhythmias (12.9%), triage (6.9%), perioperative myocardial infarction or cardiac arrest (5.0%), coagulopathy (4.0%), sepsis syndrome (4.0%), cardiac graft failure (3.0%), and device related (1.0%). The one device-related death was a venous cannula dislodgment in the intensive care unit with subsequent exsanguination. Device-related complications were seen in only 1.6% of patients. CONCLUSIONS: Bio-Medicus centrifugal ventricular support can be implemented rapidly and relatively easily. There are few device-related complications and the cost is relatively inexpensive compared with other assist systems. This series demonstrates that a substantial number of patients who experience reversible postcardiotomy myocardial injury will benefit from temporary centrifugal ventricular support.

Outcome of the native lung after single lung transplant. Multiorgan Transplant Group.

Twenty-one long-term survivors of single lung transplant since 1987 have been followed from 7 to 81 months. Posttransplant complications unique to the native lung and their impact on patient outcome are reported. In 7 of 21 recipients of single lung transplant, clinical complications in the native lung developed, including infection, pulmonary infarction, and severe ventilation-perfusion mismatching. Impact on the patient has ranged from little effect (prolongation of hospital or ICU stay) to recurrent severe infections, the need for surgical intervention, and a possible contribution to the recurrence of original disease--giant cell interstitial pneumonitis. The remaining native lung can be a source of significant complications following single lung transplant. Pretransplant diagnoses other than uncomplicated idiopathic pulmonary fibrosis seem to be most frequently associated with compromise of function or risk of infection arising from the native lung.

Giant cell interstitial pneumonitis. Disease recurrence in the transplanted lung.

Recurrence of the original disease in the transplanted organ is well reported in renal transplant recipients. There have been no previously fully documented cases of recurrence of the original disease after lung transplantation. We report a patient who underwent single-lung transplant in 1990 for end-stage respiratory failure secondary to biopsy-proved giant cell interstitial pneumonitis (GIP). There was no further industrial exposure. Surveillance bronchoscopies and biopsies post-transplant demonstrated eosinophils and giant cells in the bronchoalveolar lavage of both lungs, and in biopsies of the transplanted organ. Two years after successful transplantation the patient deteriorated and underwent open lung biopsy, which demonstrated not only bronchiolitis obliterans but also the classic features of GIP. There was no evidence of inorganic particles in the transplanted lung. Autopsy confirmed the presence of numerous giant cells characteristic of GIP with associated fibrosis throughout the transplanted lung. Although tungsten and other inorganic particles were again demonstrated in the native lung, there was no evidence of tungsten particles in the transplanted lungs. We believe that this case documents recurrence of the original disease after lung transplantation. The absence of unusual inorganic particles in the transplanted lung in the face of the classic picture of GIP is highly suggestive of an autoimmune mechanism for this occupation-associated disease. The appropriateness of transplant in the management of this lung disease should be reviewed further.

Hypertension after lung transplantation.

Hypertension is a recognized side effect of cyclosporine administration after kidney, heart, and bone-marrow transplantation. The incidence has not been previously reported after lung transplantation. We reviewed the incidence and potential causes of hypertension in recipients of single and double lung transplants. Twenty-one previously normotensive, stable recipients of lung transplants were reviewed retrospectively to determine the incidence of hypertension. Renal function as measured by blood urea nitrogen, creatinine, prednisone, and cyclosporine levels and dosages were determined at time of onset of hypertension. Hypertension developed in 14 of 21 previously normotensive patients (66%) followed from 4 to 64 months after transplantation (mean onset 11 months after transplantation). Renal function was diminished in all patients after transplantation. Neither the level of renal dysfunction nor cyclosporine dosage or level predicted the development of hypertension. The incidence of hypertension in lung transplant recipients was comparable to that reported in cyclosporine-treated kidney transplant patients (67%) and bone-marrow transplant patients (60%) but was less than that in heart transplant recipients (90%). Preserved cardiac innervation may explain the lower incidence of hypertension in lung compared with heart transplant recipients in the presence of comparable immunosuppressives and renal function. Time to onset of hypertension in lung transplant recipients is delayed compared with that in other organ transplants. This suggests that additional mechanisms as yet unexplored may be invoked.

Multi-organ procurement utilizing cardiopulmonary bypass and profound hypothermic circulatory arrest.

Despite advances in preservation solutions, hypothermia remains a critical component of organ preservation for transplantation. Many surgeons involved in multi-organ procurement procedures have expressed concern about the possible detrimental effects of cardiopulmonary bypass and profound hypothermic circulatory arrest on non-thoracic transplant organ function. In order to assess the validity of these concerns, a review of 20 multi-organ harvest procedures performed utilizing cardiopulmonary bypass and profound hypothermic circulatory arrest was undertaken. In all instances this technique was combined with organ flushing utilizing cold preservation solution. Adequate data was available to assess post-transplant organ function of all organs recovered in 16 procedures. Indication for the use of this technique was procurement of a heart-lung bloc in 16 instances and donor instability (hypotension) refractory to volume loading and inotropic agents in 4 instances. Organs obtained, including all organs from unstable donors which would otherwise have been lost, functioned, acceptably. Additionally, blood drained into the pump was used for recipient transfusion in 8 instances. This report documents that cardiopulmonary bypass and profound hypothermic circulatory arrest may be easily combined with traditional procurement flushing techniques and it provides excellent organ preservation for subsequent transplantation. This approach can optimize organ recovery from hemodynamically unstable donors, increasing the number available for transplantation.

Paraplegia associated with the use of oxidized cellulose in posterolateral thoracotomy incisions.

Three patients suffered permanent neurologic injury after oxidized regenerated cellulose migrated into the spinal canal after thoracotomy. These cases are reported to alert surgeons of this potential complication when oxidized cellulose is used to achieve hemostasis in the posterior angle of the thoracotomy incision.

Systolic and diastolic ventricular performance at rest and during exercise in heart transplant recipients.

Left ventricular dysfunction has been described in the transplanted heart. To further define these abnormalities in cardiac performance and relate for the first time diastolic to systolic function in the transplanted heart, we investigated 28 clinically stable recipients of orthotopic heart transplantation. Patients underwent blood pool radionuclide angiography performed at rest early after transplantation (18 +/- 13 days, mean +/- SD) and at rest and at exercise late after transplantation (248 +/- 194 days). Systolic ventricular performance was assessed by right and left ventricular ejection fractions, whereas diastolic left ventricular function was evaluated by the peak diastolic filling rate and its time of occurrence. Early after transplantation the left ventricular ejection fraction (54.0% +/- 6.0%) was significantly lower (p less than 0.001) than that of normal subjects of similar ages (61% +/- 6.6%). Mean right ventricular ejection fraction (47% +/- 6.0%) was comparable with that of normal subjects (49% +/- 4%) and abnormal in only three of 21 patients. Rest peak diastolic filling rate and time to peak diastolic filling rate were comparable with values from normal subjects in our laboratory. Late after transplantation resting left and right ventricular ejection fractions, peak diastolic filling rate, and time to peak diastolic filling rate were similar to the values found early after transplantation. During exercise significant increases occurred in the left ventricular ejection fraction (p less than 0.02), the right ventricular ejection fraction (p less than 0.02), and the peak diastolic filling rate (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed recovery of severely "stunned" myocardium with the support of a left ventricular assist device after coronary artery bypass graft surgery.

A 53 year old man underwent repeat coronary artery bypass graft surgery after presenting with unstable angina. Because of intraoperative ischemia, the patient developed profound left ventricular dysfunction requiring placement of a left ventricular assist device and intraaortic balloon pump and catecholamine infusion. Serial radionuclide ventriculograms documented delayed recovery of the severely stunned myocardium with mechanical and pharmacologic support.

Bronchodilators in chronic air-flow limitation. Effects on airway function, exercise capacity, and quality of life.

We conducted a trial of inhaled salbutamol and orally administered theophylline in patients whose acute response to inhaled salbutamol was less than 25% of their baseline FEV1. Patients underwent 4 treatment periods, each of 2 wk duration, during which they received the following combinations: placebo-placebo, placebo-salbutamol, placebo-theophylline, and salbutamol-theophylline. The 19 patient who completed the study were all males with a mean age of 65 +/- 7.4 yr, mean FEV1 of 1.02 +/- 0.38, and mean VC of 2.73 +/- 0.19. Outcomes included twice-daily recordings of peak flow rates, spirometry, the distance patients could walk in 6 min, and clinical symptoms of dyspnea, fatigue, and emotional function. Clinically important and statistically significant differences between the 4 periods were noted on both physiologic and functional outcomes. For the group as a whole, improvement with inhaled salbutamol and orally administered theophylline was comparable, and additional benefit was gained from a combination of the 2 drugs. We conclude that both inhaled salbutamol and orally administered theophylline can improve airflow obstruction, functional exercise capacity, and quality of life in patients with primarily fixed air-flow limitation.

Evolution of hemodynamics after orthotopic heart and heart-lung transplantation: early restrictive patterns persisting in occult fashion.

Though successfully transplanted hearts respond in such a way that individuals remain remarkably asymptomatic, they do not function normally. Characterization of early hemodynamic patterns and their evolvement has not been done. The evolution of hemodynamic indices in 20 patients receiving orthotopic heart (n = 17) or combined heart-lung (n = 3) transplants is therefore documented. In 15 isolated heart recipients, right heart catheterization was performed at 24 to 48 hours, 1 to 2 weeks, 4 to 8 weeks, and greater than 3 months after surgery at the time of routine endomyocardial biopsy. Early, patients had elevated mean blood pressure (96 +/- 14 mm Hg, mean +/- standard deviation), mean right atrial pressure (15 +/- 6 mm Hg), right ventricular end-diastolic pressure (16 +/- 7 mm Hg), mean pulmonary artery pressure (30 +/- 7 mm Hg), and mean pulmonary capillary wedge pressure (19 +/- 6 mm Hg), but normal resting heart rate (96 +/- 14 beats/min) and cardiac output (5.6 +/- 1.6 L/min). Heart rate, blood pressure, and output did not change during follow-up, but right atrial pressure decreased dramatically (4 +/- 2 mm Hg at 3 months), as did right ventricular end-diastolic pressure (4 +/- 4 mm Hg), mean pulmonary artery pressure (21 +/- 8 mm Hg), and pulmonary capillary wedge pressure (11 +/- 4 mm Hg). Analysis of right heart filling dynamics revealed an abnormal inspiratory rise in mean right atrial pressure (15 +/- 6 and 27 +/- 7 mm Hg at 24 to 48 hours) that subsequently resolved. In eight patients whose resting follow-up right heart pressures normalized, rapid volume challenge uncovered occult restrictive right atrial pressure patterns that increased from 4 +/- 4 to 9 +/- 4 mm Hg after infusion of saline solution. Kussmaul's response was not apparent with prevolume infusion, but volume expansion caused appearance of this hemodynamic pattern. All patients had early evidence of tricuspid insufficiency, but in two patients, the Doppler regurgitant fraction was over 50%. These two individuals had hemodynamics similar to the other 15 patients initially, but in contrast, their right heart filling pressures did not change during follow-up. Other significant echocardiographic findings included enlarged atria and increased left ventricular mass in all patients. In two of three combined heart-lung transplant patients, similar hemodynamic patterns were evident. Rejection indices did not correlate with hemodynamic observations. Thus a characteristic evolvement of hemodynamics in heart and heart-lung transplants that mimic dynamics associated with restrictive myocardial disease is documented.(ABSTRACT TRUNCATED AT 400 WORDS)

Popliteal vein pseudoaneurysm: a case report.

This is a case report of an athletic, middle-aged man with a remote history of penetrating right leg trauma who developed a pulmonary embolism, thrombosis of the popliteal vein, a mass in the popliteal fossa, and acute ischemia of the right lower leg. At operation a thrombosed pseudoaneurysm was found arising from a defect in the popliteal vein with extrinsic compression of the popliteal artery. The defect was patched with autogenous vein and the long-term result was excellent. Pseudoaneurysm of the popliteal vein is a previously unreported entity. Popliteal venous aneurysms usually begin with phlebitic or pulmonary thromboembolic manifestations and present a diagnostic challenge. Venous aneurysms in general are uncommon pathologic entities with a diverse etiology; the current etiologic concepts and classification are briefly discussed in the text. A new differential diagnosis for masses in the popliteal fossa is introduced by this report.

Perioperative antibiotic therapy for penetrating injuries of the abdomen.

From 1979 through 1981, 152 patients with penetrating injuries of the intra-abdominal gastrointestinal tract were placed on one of three different perioperative antibiotic regimens in a prospective randomized fashion. The three regimens were A) cefamandole 2 grams every 4 hours, B) cefoxitin 2 grams every 6 hours, and C) ticarcillin 3 grams every 4 hours and tobramycin 1.5 mg/kg every 8 hours. Antibiotics were administered intravenously before and for 48 hours following surgical exploration and repair. The three treatment groups were similar with respect to age, average number of organ injuries, and distribution of organ injuries. Cefoxitin-treated patients experienced uneventful recoveries more often than cefamandole-treated patients (94% vs. 80.3%, p less than 0.05) when the incidence of gram-negative wound infection and intra-abdominal abscess formation was considered, while the number of patients who experienced uneventful recoveries in the ticarcillin-tobramycin group was not statistically different from the other two groups of patients. Bacteroides fragilis was isolated from three of the six abscesses occurring in the cefamandole-treated group, while no anaerobes were isolated from abscesses in patients treated with either of the other two regimens. The results of this study suggest that the most effective perioperative antibiotic regimen for patients with penetrating gastrointestinal wounds should possess activity against both aerobic and anaerobic flora of the bowel.