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S M Pham

Publications and source records attributed to S M Pham.

At least 73 records · Page 4Linked to original sources
PubMed1994

Tension pneumoperitoneum after heart-lung transplantation.

Tension pneumoperitoneum is a medical emergency. We report 2 cases in which tension pneumoperitoneum occurred after heart-lung transplantation and was related to positive-pressure ventilation and a transdiaphragmatic passage of omentum used to wrap the airway anastomosis. Management in these patients was targeted toward decompression of intraperitoneal air with percutaneous needle or tube placement without exploratory laparotomy, and tube thoracostomy for the concomitant pneumothorax.

Female↗
PubMed1994

Risk stratification using the Society of Thoracic Surgeons Program.

In an era of progressive cost containment and public scrutiny, the wisdom of aggressive surgical therapy for high-risk candidates has been questioned. At our center in the previous 24 months, 728 patients with coronary artery disease were entered into The Society of Thoracic Surgeons national database, and the hospital outcomes plus length of stay were analyzed. Patients were separated according to the predicted mortality based on the groupings in The Society of Thoracic Surgeons database: 0 to 5% (453 patients); 5% to 10% (126 patients); 10% to 20% (96 patients); 20% to 30% (17 patients); and 30% and greater (36 patients). There was a close correlation with the predicted rates of mortality. Importantly, the preoperative risk stratification demonstrated a strong correlation with the significant morbidity and excessive length of stay in the highest-risk groups (predicted risk of 20% to > or = 30%). The incidences of the most common complications in the group with the highest predicted risk (> or = 30%) were 28%, renal failure; 33%, ventilator dependence; and 17%, cardiac arrest. In addition, at short-term follow-up (6 to 8 months), a 24.3% mortality was identified in patients with a predicted mortality that exceeded 20%. These data quantify the risks and morbidities associated with the care of seriously ill patients with coronary artery disease and demonstrate the need for professional and public discussions focusing on the association of a high preoperative risk status and the consumption of resources.

Aged↗
PubMed1994

Lung transplantation at the University of Pittsburgh: 1982 to 1994.

Lung transplantation is a growing modality of treatment for patients with end-stage lung disease. In our program, survival has improved significantly in recent experience. Progress in candidate and donor selection, allograft preservation technique, recipient surgery, and postoperative management combine to reduce recipient morbidity and mortality. Although the tailored antibiotic treatment has significantly reduced the risk of bacterial pneumonia within 2 weeks after operation, infection is still a major cause of death for long-term recipients. Extensive studies need to be continued to understand the pathogenesis of OB and to establish the treatment for OB.

Adolescent↗
PubMed1994

Cardiac transplantation at the University of Pittsburgh: 1994 update.

During the past 14 years, 746 hearts have been transplanted at the University of Pittsburgh. Immunosuppression has evolved from a CsA-based protocol with or without lympholytic prophylaxis to a tacrolimus-based protocol. Tacrolimus offers comparable survival to the conventional immunosuppression but is associated with lesser side effects and lower recurrent rejection. It also serves as an effective rescue agent for intractable rejection in patients receiving CsA-based immunosuppression. However, the shortage of donors, chronic rejection, and the morbidity associated with chronic use of nonspecific immunosuppression remain the major limitations in clinical transplantation. Currently, research at the University of Pittsburgh focuses on the induction of donor-specific transplantation tolerance in order to eliminate the morbidity associated with nonspecific immunosuppression and on left ventricular-assist devices as a bridge and/or an alternative to cardiac transplantation.

Actuarial Analysis↗
PubMed1993

A decade of lung transplantation.

OBJECTIVE: The experience accrued at the University of Pittsburgh between March 1982 and December 1992 in the various forms of lung transplantation, including heart-lung, double lung, and single lung, is discussed. SUMMARY BACKGROUND DATA: Heart-lung (n = 97) was the most commonly performed operation followed by double lung (n = 80) and single lung (n = 68). Major indications included primary pulmonary hypertension (n = 76), obstructive lung disease (n = 57), Eisenmenger's syndrome (n = 42), cystic fibrosis (n = 32), and retransplantation (n = 13). Since May 1991, 115 procedures have been performed and heart-lung transplantation has decreased from 61% to 15% of the cases with a corresponding doubling in double lung from 24% to 43% and single lung from 15% to 42%. RESULTS: The 1-, 2-, and 5-year survival rates in all 232 recipients were 61%, 55%, and 44%, respectively. The actuarial survival rate was significantly better for those 107 recent recipients compared to the 125 early recipients (70% vs. 61%). Overall, the 63 single (70%) and 74 double (65%) lung procedures were more successful than heart-lung transplantation (53%). Recently, however, lung transplantation has been associated with an improvement in the survival rate from 48% to 72%. The survival rate has also improved from 53% to 77% for single lung transplant recipients. The causes of death in 106 recipients included infection (n = 40), early allograft dysfunction (n = 23), obliterative bronchiolitis (n = 13), and inoperative bleeding (n = 10). Poor outcomes also included technical problems (n = 6), lymphoma (n = 4), acute rejection (n = 3), diaphragmatic paralysis (n = 2), multisystem organ failure (n = 2), stroke (n = 2), liver failure (n = 1), and airway dehiscence (n = 1). CONCLUSIONS: The long-term outlook for lung transplant recipients has improved. There appears to be significant conservation of organs with single lung and double lung transplantation, finding greater acceptance for diseases once exclusively treated by heart-lung transplantation alone. The improved long-term outlook will be dependent upon better treatment for chronic rejection of the airways that histologically is defined by obliterative bronchiolitis.

Adolescent↗
PubMed1992

Spatial and temporal changes in compliance following implantation of bioresorbable vascular grafts.

Compliance matching between the host vessel and vascular grafts used for small-diameter arterial replacements is thought to be important for long-term patency. However, currently available grafts elicit fibroplastic reactions, resulting in decreasing compliance with time after implantation. Bioresorbable prostheses elicit ingrowth of myofibroblasts containing abundant contractile elements. This led us to investigate whether compliance of implanted bioresorbable prostheses decreased as a function of time and if the kinetics of change correlated with the progression of tissue ingrowth. Woven polyglactin 910 prostheses (10 mm x 4 mm i.d.) were implanted into adult NZW rabbit infrarenal aortas and replicates were harvested serially through 8 months. Control grafts were implanted, and immediately resected. Dynamic compliance was measured at 1-mm axial increments along each explant using a pulse duplicator apparatus which exposed the harvested samples to realistic pulsatile hemodynamics. Compliance was calculated for proximal, mid, and distal segments of each graft and averaged at each time point by grouping into control (zero time, n = 3), early (1-4 weeks, n = 13), and late (6-36 weeks, n = 9) explant periods. At late explant periods both proximal and distal compliance were significantly greater than mid graft compliance (p < .02 and p < .03, respectively). There was a significant increase in proximal compliance between early and late explant times (p < .01). Measured increases in mid and distal segment compliance over time did not reach statistical significance. Myofibroblast laden tissue ingrowth into the inner capsule followed macrophage phagocytosis and was nearly complete prior to the time that an increase in compliance was demonstrated. Thus since the major histologic episodes precede the change in compliance, these are not likely initiated by this biomechanical change. We hypothesize the graft resorption coupled with the ingrowth of more compliant tissue likely leads to the increased compliance of the graft material.

Animals↗
PubMed1992

Mitogen responses of lymphocytes from lung transplant recipients--correlation with rejection and infection.

Proliferative responses to nonspecific mitogens were analyzed for 119 bronchoalveolar lavages and 108 concurrent peripheral blood samples from 35 lung transplant patients. The patients were classified at each time as normal, rejecting, or infected on the basis of trans-bronchial biopsy, culture results, clinical signs, and pulmonary function. During rejection episodes the bronchoalveolar lavage responses to concanavalin A and phytohemagglutinin were significantly increased (P less than 0.004 and P less than 0.006, respectively). The differences were less pronounced when rejection occurred within 30 days after bolus immunosuppressive therapy, either as immunoprophylaxis or as treatment for a previous rejection episode, and were not significantly different from normal. Differences in response during rejection were limited to the graft; analysis of circulating T cells was not helpful (P = NS). In contrast, markedly depressed responses to Con A and PHA were seen during infection. Significant differences were observed both in the graft (P less than 0.007) and in circulating lymphocytes (P less than 0.02), suggesting that global depression of mitogen response is associated with immunocompromise. Sequential analysis of 6 patients showed that individual changes in mitogen response paralleled those seen in the population (P less than 0.046, normal vs. rejection and P less than 0.043 normal). These findings suggest that mitogen assays of bronchoalveolar lavage lymphocytes and, to a lesser extent, PBL, are clinically useful in assessing intragraft immunocompetence and in distinguishing rejection from infection in lung transplant patients.

Bronchoalveolar Lavage Fluid↗
PubMed1989

Hemodynamic effects on endothelial cell monolayer detachment from vascular prostheses.

The establishment of an early blood-contacting endothelialized surface may improve the graft-host relationship. This study evaluated the adherence of indium 111-radiolabeled endothelial cells that were cultured to confluence on fibronectin-treated polyester elastomer (Hytrel) grafts that were perfused for two hours on a pulse duplicator apparatus under high- and low-shear conditions. Perfusate samples were serially assayed for radioactivity. After perfusion, grafts were sectioned into four segments and assayed for retained radioactivity. All graft segments were hematoxylin stained and examined under light microscopy for evaluation of cell density. Excellent endothelial cell adherence (90%) was observed under both hemodynamic conditions at 120 minutes, with most losses occurring within the first 15 minutes. No differences were seen between high- and low-shear conditions or proximal vs distal graft segments.

Animals↗
PubMed1989

Hemodynamics alter arterial low-density lipoprotein metabolism.

We have investigated the role of hemodynamic factors on low-density lipoprotein transport and metabolism in the intact arterial wall. Freshly excised canine carotid blood vessels were exposed to well-defined pulsatile flow in vitro for continuous periods up to 20 hours. We chose to impose the following hemodynamic conditions on our test carotid arteries: normotension, hypertension (at physiologic flow conditions), and hypertension coupled with elevated flow of canine serum perfusate. In several experiments the effect of endothelial denudation was examined in carotid arteries exposed to normotensive pulsatile flow. A trapped ligand method was used for quantitating low-density lipoprotein uptake and metabolism in the arterial wall. The distribution of both intact and degraded low-density lipoprotein fractions was determined from measurements of radiolabelled low-density lipoprotein activity within thin radial sections of perfused arteries. Our results suggest that both hypertensive hemodynamic simulations exacerbate the uptake of low-density lipoprotein within the arterial wall (by a factor of three to nine). The percentage of low-density lipoprotein that undergoes irreversible degradation falls from 41% under normotensive conditions to below 30% when hypertensive conditions are imposed, indicating that degradative processes are not proportionally elevated with the accelerated influx. A similar pattern is observed for deendothelialized vessels.

Animals↗
PubMed1989

Hemodynamic consequences of Foley catheter control in experiment penetrating cardiac wounds.

Insertion of the Foley catheter has been recommended to control bleeding from penetrating cardiac wounds. Potential complications from this maneuver include enlargement of the tear in the myocardium or further impediment to cardiac function by the balloon. This study was done to evaluate the hemodynamic consequences of the balloon catheter when it was used to control bleeding in cardiac stab wounds created in pigs. A significant decrease in cardiac function occurred with control of the bleeding by the balloon catheter. This effect was dependent on the size of the balloon and cardiac location.

Animals↗
PubMedDate not supplied

ECMO support for adult patients with acute respiratory failure.

The authors analyzed factors that may influence the outcome of adult patients with respiratory failure who were treated with ECMO. Between December 1990 and July 1995, the authors used ECMO to support 33 patients (age range, 17-56 years) with respiratory failure from adult respiratory distress syndrome (ARDS; n = 9), primary graft failure after lung transplantation (n = 16), late graft failure after lung transplantation (n = 5), and miscellaneous reasons (n = 3). Twenty (61%) patients were successfully weaned from ECMO, and 13 (39%) survived to hospital discharge. Venoarterial ECMO was used in 46% of survivors, compared with 60% of nonsurvivors (p = 0.43). The time on mechanical support before ECMO and the duration on ECMO for survivors and nonsurvivors was 2.9 +/- 1.8 days vs 5.0 +/- 1.3 days (p = 0.35), and 6.5 +/- 1.8 days vs 5.7 +/- 1.1 days (p = 0.68), respectively. Compared with the nonsurvivors, survivors had higher PF ratios (PaO2/FIO2; 104 +/- 33 vs 81 +/- 8, p = 0.43) before ECMO was initiated, although the differences were not significant. Among the patients who received ECMO for primary graft failure, 75% were weaned from ECMO, and 56% survived to discharge. ECMO is beneficial for adult patients with respiratory failure, especially those with primary graft failure after lung transplantation.

Acute Disease↗
PubMedDate not supplied

Acanthamoeba infection in lung transplantation: report of a case and review of the literature.

A 49-year-old woman underwent bilateral lung transplantation for advanced idiopathic pulmonary fibrosis. During the postoperative period she received immunosuppressive medications as well as corticosteroids. Aspergillus fumigatus grew from a sputum sample, and she was treated with nebulized amphotericin. She was discharged on tacrolimus and prednisone. After initially doing well, she required re-hospitalization for treatment of cytomegalovirus and Pseudomonas aeruginosa pneumonia. She was treated with ganciclovir and cefepime and, after a 2-week hospitalization, was discharged. Seven months after transplantation she developed progressive sinusitis, treated with antibiotics and sinus debridement surgery. Aspergillus organisms were recovered and, at the periphery of the tangled masses of Aspergillus hyphae, numerous amebic cysts were also identified, which were morphologically consistent with Acanthamoeba spp. Subsequent electron microscopy and immunofluorescent staining confirmed this impression. She was initially treated with intravenous amphotericin, later changed to voriconazole and caspofungin. Debridement of the sinuses 3 weeks later revealed fungal hyphae but no amebae. Infections with Acanthamoeba have rarely been reported in lung transplantation but have been recognized in bone-marrow and renal transplant patients, and have been lethal in many cases, particularly in patients with immunosuppression due to human immunodeficiency virus infection. More recently, aggressive antimicrobial therapy has resulted in successful outcomes, as discussed herein.

Acanthamoeba↗
PubMedDate not supplied

The pigtail catheter for pleural drainage: a less invasive alternative to tube thoracostomy.

BACKGROUND: Tube thoracostomy remains the standard of care for the treatment of pneumothoraces and simple effusions. This report describes a favorable experience with the 8.3 French pigtail catheter as a less invasive alternative to traditional chest tube insertion. METHODS: We retrospectively reviewed 109 consecutive pigtail catheter placements. Catheters were inserted under local anesthesia at the bedside without radiographic guidance. Pre- and post-insertion chest radiographs were reviewed to determine efficacy of drainage. RESULTS: Fifty-one of 109 patients (47%) were mechanically ventilated and 26 patients (24%) had a coagulopathy. There were no complications related to pigtail catheter insertion. Seventy-seven pigtail catheters were placed for pleural effusion and 32 for pneumothorax. Mean effusion volume decreased from 43 to 9 percent, and drainage averaged 2899 ml over 97 hours. Mean pneumothorax size diminished from 38 to 1 percent during an average 71-hour placement. Clinical success rates in the effusion and pneumothorax groups were 86 and 81 percent, respectively. CONCLUSION: The pigtail catheter offers reliable treatment of pneumothoraces and simple effusions and is a safe and less invasive alternative to tube thoracostomy.

Adolescent↗
PubMedDate not supplied

Interleukin-6, a marker of preservation injury in clinical lung transplantation.

Interleukin-6 (IL-6) is one of the cytokines produced by human alveolar macrophages, lung parenchyma, and other cells in response to injury and infection. We hypothesized that IL-6 is released from poorly preserved lung grafts and may serve as a marker of preservation injury. Sixteen patients who received lung allografts were enrolled in this study. The average ischemic time was 284 +/- 78 minutes. Serum IL-6 level was measured before and at 4 and 24 hours after reperfusion of the grafts by an enzyme-linked immunosorbent assay. Preservation injury was assessed by (1) the need for prolonged intubation (> 7 days), (2) the arterial/alveolar oxygen tension ratio (PaO2/PAO2 ratio) at 4 hours after graft reperfusion (only in heart-lung or double lung recipients), (3) the presence of diffuse alveolar damage on first lung biopsy, and (4) the 30-day graft survival rate. IL-6 level peaked at 4 hours after reperfusion and returned to baseline at 24 hours. The patients were divided into group I (n = 6) and group II (n = 10), depending on whether the 4-hour IL-6 level was more than 1000 pg/ml or less than 500 pg/ml, respectively. Group I patients required longer intubation (p < 0.01) and had a lower PaO2/PAO2 ratio (p < 0.001), more diffuse alveolar damage (p < 0.01), and a lower graft survival rate (p < 0.01) than those of group II. No bacterial, fungal, or viral infection was found during postoperative week 1 in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Comparison of outcomes after single and bilateral lung transplantation for obstructive lung disease.

BACKGROUND AND METHODS: To determine the long-term functional outcome for single versus bilateral lung transplant for nonseptic obstructive lung disease, we compared the results from 39 single and nine bilateral lung transplant procedures. The nine bilateral lung transplants included three en bloc double lung and six bilateral sequential lung transplants. RESULTS: Early deaths within 30 days of transplantation occurred in two of nine (22%) bilateral and 4 of 39 (10%) single lung transplants (p = Not significant). Compared with pretransplant values, pulmonary function as assessed by the spirometric indexes of the percent predicted forced vital capacity, forced expiratory volume in one second, forced expiratory volume in one second/forced vital capacity, and forced expiratory flow at 25% and 75% of forced vital capacity improved significantly up to at least 12 months after transplantation for both single and bilateral lung transplant recipients. The degree of pulmonary function improvement was better in single as compared with bilateral lung recipients. By 6 months after transplantation, all but one single and all bilateral lung recipients were in New York Heart Association class I or II (p = Not significant). One-year survival was significantly better after single (77%) compared with after bilateral lung transplantation (35%) (p < 0.05). CONCLUSIONS: These results suggest that single lung transplantation is the procedure of choice for patients with nonseptic obstructive lung disease.

Adolescent↗
PubMedDate not supplied

Development of an intravenous membrane oxygenator: a new concept in mechanical support for the failing lung.

An intravenous membrane oxygenator is being developed to supplement oxygen and carbon dioxide exchange in patients with temporary and potentially reversible lung failure in either a lung transplantation setting or in cases of acute respiratory distress from multiple causes. Our device incorporates a pulsatile balloon that is centrally located and around which are mounted microporous hollow fibers. Oxygen is vaccuumed through the fibers with resultant gas exchange. The rhythmic pulsations of the balloon enhance cross-flow and three-dimensional convective mixing at the blood-fiber interface and thus promote more efficient oxygen-carbon dioxide exchange. Seven intravenous membrane oxygenator prototypes have been designed and fabricated. Modifications in design have led to a progressive improvement in gas flux. Gas exchange performance measured in vitro and with both saline solution and fresh ox blood have shown gas exchange as high as 203 ml/min/m2 for oxygen and 182 ml/min/m2 for carbon dioxide. In vivo dog experiments with the device positioned in the inferior vena cava and right atrium have shown over a 50% increase in oxygen flux with balloon activation versus the static situation without changes in hemodynamics. The size of the prototype tested in animals can be scaled up fivefold for anticipated human trials. Our results indicate that our intravenous membrane oxygenator prototypes now under development may be an alternative to extracorporeal membrane oxygenation in the treatment of temporary respiratory failure.

Animals↗