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Dive into the research topics where Robert J. Keenan is active.

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Featured researches published by Robert J. Keenan.


The Annals of Thoracic Surgery | 1993

Postoperative pain-related morbidity: Video-assisted thoracic surgery versus thoracotomy☆

Rodney J. Landreneau; Stephen R. Hazelrigg; Michael J. Mack; Robert D. Dowling; David F. Burke; Joseph Gavlick; Maureen K. Perrino; Pamela S. Ritter; Claudia M. Bowers; Jennifer Defino; Susan Nunchuck; J. A. Freeman; Robert J. Keenan; Peter F. Ferson

One hundred thirty-eight consecutive, nonrandomized patients, with equivalent demographic and preoperative physiologic parameters, underwent either a video-assisted thoracic surgical (VATS) approach (n = 81) or a limited lateral thoracotomy (LLT) approach (n = 57) to accomplish pulmonary resection for peripheral lung lesions (< or = 3 cm in diameter). Wedge resection was done in 74 VATS patients and 19 LLT patients. Seven patients underwent VATS lobectomy and 38 patients had lobectomy performed through an LLT. Pain was quantitated by postoperative narcotic requirements, the need for intercostal/epidural analgesia, and patient perception of pain index scoring. Shoulder and pulmonary function (forced expiratory volume in 1 second) were measured preoperatively, 3 days postoperatively, and at 3 weeks of follow-up. Patients undergoing VATS experienced significantly less postoperative pain. No patients undergoing VATS required intercostal block/epidural analgesia; 31 LLT patients (54%) required this treatment for breakthrough pain (p = 0.001). Narcotic requirements were less (p = 0.05) among VATS patients, which correlated with lower perception of pain index after operation for VATS patients. Shoulder girdle strength was equally impaired at day 3, but function was more improved in VATS patients at 3 weeks (p = 0.01). Patients undergoing wedge resection alone by LLT had greater impairment in early (day 3) pulmonary function (forced expiratory volume in 1 second) (p = 0.002); this difference from VATS was not sustained at 3 weeks. Video-assisted thoracic surgery is associated with reduced pain, shoulder dysfunction, and early pulmonary impairment compared with LLT for select patients requiring pulmonary resection.


The New England Journal of Medicine | 1996

Improvement in pulmonary function and elastic recoil after Lung reduction surgery for diffuse emphysema

Frank C. Sciurba; Robert M. Rogers; Robert J. Keenan; William A. Slivka; John Gorcsan; Peter F. Ferson; John M. Holbert; Manuel L. Brown; Rodney J. Landreneau

BACKGROUND Pulmonary function may improve after surgical resection of the most severely affected lung tissue (lung-reduction surgery) in patients with diffuse emphysema. The basic mechanisms responsible for the improvement, however, are not known. METHODS We studied 20 patients with diffuse emphysema before and at least three months after either a unilateral or a bilateral lung-reduction procedure. Clinical benefit was assessed by measurement of the six-minute walking distance and the transitional-dyspnea index, which is a subjective rating of the change from base line in functional impairment and the threshold for effort- and task- dependent dyspnea. Pressure-volume relations in the lungs were measured with static expiratory esophageal-balloon techniques, and right ventricular systolic function was assessed by echocardiography. RESULTS The patients had significant improvement in the transitional-dyspnea index after surgery (P<0.001). The mean (+/-SD) coefficient of retraction, an indicator of elastic recoil of the lung, improved (from 1.3+/-0.6 cm of water per liter before surgery to 1.8+/-0.8 after, P<0.001). Sixteen patients with increased elastic recoil had a greater increase in the distance walked in six minutes than the other four patients, in whom recoil did not increase (P=0.02). The improved lung recoil led to disproportionate decreases in residual volume as compared with total lung capacity (16 percent vs. 6 percent), but the decreases in both values were significant (P<0.001). Forced expiratory volume in one second increased (from 0.87+/-0.36 to 1.11+/-0.45 liters, P<0.001). End-expiratory esophageal pressure also decreased (P=0.002). These improvements in lung mechanics led to a decrease in arterial partial pressure of carbon dioxide form 42+/-6 to 38+/-5 mm Hg (P=0.006). Furthermore, the fractional change in right ventricular area, an indicator of systolic function, increased from 0.33+/-0.11 to 0.38+/-0.010 (P=0.02). CONCLUSIONS Lung-reduction surgery can produce increases in the elastic recoil of the lung in patients with diffuse emphysema, leading to short-term improvement in dyspnea and exercise tolerance.


The Journal of Thoracic and Cardiovascular Surgery | 1995

Obliterative bronchiolitis after lung and heart-lung transplantation: An analysis of risk factors and management

Ko Bando; Irvin L. Paradis; Shari Similo; Hiroaki Konishi; Kanshi Komatsu; Thomas G. Zullo; Samuel A. Yousem; John M. Close; Adriana Zeevi; Rene J. Duquesnoy; Jan D. Manzetti; Robert J. Keenan; John M. Armitage; Robert L. Hardesty; Bartley P. Griffith

With a prevalence of 34% (55/162 at-risk recipients) and a mortality of 25% (14/55 affected recipients), obliterative bronchiolitis is the most significant long-term complication after pulmonary transplantation. Because of its importance, we examined donor-recipient characteristics and antecedent clinical events to identify factors associated with development of obliterative bronchiolitis, which might be eliminated or modified to decrease its prevalence. We also compared treatment outcome between recipients whose diagnosis was made early by surveillance transbronchial lung biopsy before symptoms or decline in pulmonary function were present versus recipients whose diagnosis was made later when symptoms or declines in pulmonary function were present. Postoperative airway ischemia, an episode of moderate or severe acute rejection (grade III/IV), three or more episodes of histologic grade II (or greater) acute rejection, and cytomegalovirus disease were risk factors for development of obliterative bronchiolitis. Recipients with obliterative bronchiolitis detected in the preclinical stage were significantly more likely to be in remission than recipients who had clinical disease at the time of diagnosis: 81% (13/15) versus 33% (13/40); p < 0.05). These results indicate that acute rejection is the most significant risk factor for development of obliterative bronchiolitis and that obliterative bronchiolitis responds to treatment with augmented immunosuppression when it is detected early by surveillance transbronchial biopsy.


The Annals of Thoracic Surgery | 2000

Minimally invasive esophagectomy.

James D. Luketich; Philip R. Schauer; Neil A. Christie; Tracey L. Weigel; Siva Raja; Hiran C. Fernando; Robert J. Keenan; Ninh T. Nguyen

BACKGROUND Open esophagectomy can be associated with significant morbidity and delay return to routine activities. Minimally invasive surgery may lower the morbidity of esophagectomy but only a few small series have been published. METHODS From August 1996 to September 1999, 77 patients underwent minimally invasive esophagectomy. Initially, esophagectomy was approached totally laparoscopically or with mini-thoracotomy; thoracoscopy subsequently replaced thoracotomy. RESULTS Indications included esophageal carcinoma (n = 54), Barretts high-grade dysplasia or carcinoma in situ (n = 17), and benign miscellaneous (n = 6). There were 50 men and 27 women with an average age of 66 years (range 30 to 94 years). Median operative time was 7.5 hours (4.5 hours with > 20 case experience). Median intensive care unit stay was 1 day (range 0 to 60 days); median length of stay was 7 days (range 4 to 73 days) with no operative or hospital mortalities. There were four nonemergent conversions to open esophagectomy; major and minor complication rates were 27% and 55%, respectively. CONCLUSIONS Minimally invasive esophagectomy is technically feasible and safe in our center, which has extensive minimally invasive and open esophageal experience. Open surgery should remain the standard until future studies conclusively demonstrate advantages of minimally invasive approaches.


The Journal of Thoracic and Cardiovascular Surgery | 1996

Unilateral thoracoscopic surgical approach for diffuse emphysema.

Robert J. Keenan; Rodney J. Landreneau; Frank C. Sciurba; Peter F. Ferson; J.Michael Holbert; Manuel L. Brown; Lynda S. Fetterman; Claudia M. Bowers

We evaluated the use of a lateral thoracoscopic approach for lung reduction surgery in patients with diffuse emphysema. Sixty-seven patients with a mean age of 61.9 years underwent operation. Operative side was determined by preoperative imaging. The procedures were laser ablation in 10 patients and stapler resection in 57 patients. Ten patients, including six of the 10 patients in the laser-only group had poor outcome (death or hospitalization longer than 30 days), leading us to abandon the laser technique. Of the remaining 57 patients undergoing primary stapled resection, duration of chest tube placement averaged 13 days (range 3 to 53 days) with a mean hospital stay of 17 days (range 6 to 99 days). Seven patients required ventilation for longer than 72 hours, six patients underwent conversion of the procedure to open thoracotomy, four patients acquired arrhythmias, and three patients were treated for empyema. There was one early death (1.7%), from cardiopulmonary failure. Forty patients returned for 3-month evaluation. Significant (p < 0.0001) improvements were seen in forced vital capacity (2.69 L after vs 2.26 L before) and forced expiration volume in 1 second (1.04 L after vs 0.82 L before), with 25 of 40 patients (63%) showing an improvement of more than 20%. Lung volume measures, in particular residual volume, fell significantly. Arterial blood gas analysis revealed that carbon dioxide tension fell significantly in patients with preoperative hypercapnia (carbon dioxide tension > 45 mm Hg, p = 0.018). Six-minute walk test results improved (894 feet after vs 784 feet before, p = 0.002), and symptomatic benefit was confirmed by significant improvement in the dyspnea index. The combination of both hypercapnia and reduced single-breath diffusing capacity for carbon monoxide was significantly more frequent (p = 0.0026) and was 86% specific (5 of 6 patients) in predicting serious postoperative risk. We conclude that the lateral thoracoscopic surgical approach to diffuse emphysema offers significant improvement in pulmonary mechanics and functional impairment. Patients with a combination of hypercapnia and reduced single-breath diffusing capacity for carbon monoxide should not be considered for this procedure because of significant perioperative risk.


The Annals of Thoracic Surgery | 1997

Role of Positron Emission Tomography in Staging Esophageal Cancer

James D. Luketich; Philip R. Schauer; Carolyn C. Meltzer; Rodney J. Landreneau; G.Kathleen Urso; David W. Townsend; Peter F. Ferson; Robert J. Keenan; Chandra P. Belani

BACKGROUND Conventional noninvasive staging of esophageal cancer is inaccurate. This study investigated the role of positron emission tomography (PET) in staging esophageal cancer. METHODS Patients with potentially resectable esophageal cancer were included. A whole-body PET scan was acquired after injection of 18F-fluorodeoxyglucose and was evaluated for areas of increased focal uptake. Accuracy was determined by comparing PET with surgical staging. RESULTS Potentially resectable esophageal cancer was identified in 35 patients. Positron emission tomography detected nine sites of distant metastases missed by conventional scanning, but one false-negative PET scan occurred in a patient with a 2-mm liver lesion. There were 11 false-negative PET scans for small, intracapsular local-regional nodal metastases (mean diameter 5.2 mm; range 2 to 10 mm). For distant metastases, the sensitivity was 88%, the specificity was 93%, and the accuracy was 91%. For local-regional nodal metastases, the sensitivity was 45%, the specificity was 100%, and the accuracy was 48%. CONCLUSIONS Positron emission tomography improved our ability to detect distant metastases missed by conventional noninvasive staging of esophageal cancer. Small local-regional nodal metastases are not identified by current PET technology. Early use of PET in the staging of patients with esophageal cancer could facilitate treatment planning and identifying unsuspected distant metastases in up to 20% of patients with a negative metastatic survey by conventional staging.


Transplantation | 1991

Cytomegalovirus serologic status and postoperative infection correlated with risk of developing chronic rejection after pulmonary transplantation.

Robert J. Keenan; M. E. Lega; Paradis Il; James H. Dauber; Hanna Rabinowich; Samuel A. Yousem; Robert L. Hardesty; Bartley P. Griffith; Rene J. Duquesnoy; A. Zeevi

Twenty-seven patients received pulmonary transplants during the period since we began routine use of cytomegalovirus-seronegative blood products for CMV-seronegative recipients. Preoperative serologic status of the recipient and the occurrence of cytomegalovirus infection in the postoperative period were correlated with development of obliterative bronchiolitis (OB) as diagnosed by transbronchial biopsy (TBB). Patients included 20 heart-lung and 7 double-lung recipients. OB occurred in 18 of 27 patients. All 3 CMV seronegative recipients receiving lungs from a seropositive donor and 9 of 10 CMV recipients seropositive at the time of transplantation developed OB compared with only 6 of 14 CMV seronegative patients receiving seronegative grafts (P = 0.018). CMV infection occurred in 10/27 patients, of whom 5 were asymptomatic; 90% of these patients developed OB. Donor-specific alloreactivity, based on primed lymphocyte testing (PLT) of bronchoalveolar lavage cells was found at the time of diagnosis of OB in 23 of 27 patients. A positive PLT was significantly associated with the presence of OB (P = 0.017). We conclude that preoperative seropositive status for CMV, grafting of organs from seropositive donors, and postoperative CMV infection are significant risk factors for developing OB. That OB is, in part, an immunologically mediated form of injury and represents chronic rejection is supported by the presence of donor-specific alloreactivity in BAL lymphocytes from all recipients with OB.


The Annals of Thoracic Surgery | 1995

Clinical trial of tacrolimus versus cyclosporine in lung transplantation

Robert J. Keenan; Heroaki Konishi; Akihiko Kawai; Irvin L. Paradis; David R. Nunley; Aldo Iacono; Robert L. Hardesty; Robert J. Weyant; Bartley P. Griffith

BACKGROUND A prospective clinical trial was undertaken to compare the efficacy of tacrolimus (FK 506) versus cyclosporine as the primary immunosuppressive agent after lung transplantation. METHODS Between October 1991 and May 1994, 133 single-lung and bilateral-lung recipients were randomized to receive either cyclosporine (n = 67) or tacrolimus (n = 66). The two groups were similar in age, sex, and underlying disease. RESULTS One-year and 2-year survival rates were similar in the two groups, although the trend was toward increased survival with tacrolimus. Acute rejection episodes per 100 patient-days were fewer (p = 0.07) in the tacrolimus group (0.85) than in the cyclosporine group (1.09). Obliterative bronchiolitis developed in significantly fewer patients in the tacrolimus group (21.7%) compared with the cyclosporine group (38%) (p = 0.025), and there was greater freedom from obliterative bronchiolitis over time for patients receiving tacrolimus (p < 0.03). Significantly more cyclosporine-treated patients (n = 13) required crossover to tacrolimus than tacrolimus-treated patients to cyclosporine (n = 2) (p = 0.02). The switch to tacrolimus controlled persistent acute rejection in 6 of 9 patients. The overall incidence of infections was similar in the two groups, although bacterial infections were more common with cyclosporine (p = 0.0375), whereas the risk of fungal infection was higher with tacrolimus (p < 0.05). CONCLUSIONS This trial demonstrates the advantage of tacrolimus in reducing the risk of obliterative bronchiolitis, the most important cause of long-term morbidity and mortality after lung transplantation.


Annals of Surgery | 2000

Laparoscopic repair of giant paraesophageal hernia: 100 Consecutive cases

James D. Luketich; Siva Raja; Hiran C. Fernando; William L. Campbell; Neil A. Christie; Percival O. Buenaventura; Robert J. Keenan; Philip R. Schauer

ObjectiveTo summarize the authors’ laparoscopic experience for paraesophageal hernia (PEH). Summary Background DataLaparoscopic antireflux surgery and repair of small hiatal hernias are now routinely performed. Repair of a giant PEH is more complex and requires conventional surgery in most centers. Giant PEH accounts for approximately 5% of all hiatal hernias. Medical management may be associated with a 50% progression of symptoms and a significant death rate. Conventional open surgery has a low death rate, but complications are significant and return to routine activities is delayed in this frequently elderly population. Recently, short-term outcome studies have reported that minimally invasive approaches to PEH may be associated with a lower complication rate, a shorter hospital stay, and faster recovery. MethodsFrom July 1995 to February 2000, 100 patients (median age 68) underwent laparoscopic repair of a giant PEH. Follow-up included heartburn scores and quality of life measurements using the SF-12 physical component and mental component summary scores. ResultsThere were 8 type II hernias, 85 type III, and 7 type IV. Sac removal, crural repair, and antireflux procedures were performed (72 Nissen, 27 Collis-Nissen). The 30-day death rate was zero; there was one surgery-related death at 5 months from a perioperative stroke. Intraoperative complications included pneumothorax, esophageal perforation, and gastric perforation. There were three conversions to open surgery. Major postoperative complications included stroke, myocardial infarction, pulmonary emboli, adult respiratory distress syndrome, and repeat operations (two for abscess and one each for hematoma, repair leak, and recurrent hernia). Median length of stay was 2 days. Median follow-up at 12 months revealed resumption of proton pump inhibitors in 10 patients and one repeat operation for recurrence. The mean heartburn score was 2.3 (0, best; 45, worst); the satisfaction score was 91%; physical and mental component summary scores were 49 and 54, respectively (normal, 50). ConclusionThis report represents the largest series to date of laparoscopic repair of giant PEH. In the authors’ center with extensive experience in minimally invasive surgery, laparoscopic repair of giant PEH was successfully performed in 97% of patients, with a minimal complication rate, a 2-day length of stay, and good intermediate results.


The Journal of Thoracic and Cardiovascular Surgery | 1995

Analysis of time-dependent risks for infection, rejection, and death after pulmonary transplantation

Ko Bando; Irvin L. Paradis; Kanshi Komatsu; Hiroaki Konishi; Masato Matsushima; Robert J. Keenan; Robert L. Hardesty; John M. Armitage; Bartley P. Griffith

Infection and rejection remain the greatest threats to the survival of pulmonary allograft recipients. Furthermore, a relationship may exist between these events, because the occurrence of one may predispose to the other. By using multivariate analysis for repeated events, we analyzed the risk factors for bacterial, fungal, and viral infection, grade II or greater acute rejection, and death among 239 lung transplant recipients who received 250 allografts between January 1988 and September 1993. A total of 90 deaths, 491 episodes of acute rejection, and 542 infectious episodes occurred during a follow-up of 6 to 71 months. The hazard or risk patterns of death, infection, and rejection each followed an extremely high risk during the first 100 days after transplantation, a second modest risk period at 800 to 1200 days, and a lower constant risk. Infection and graft failure manifested by diffuse alveolar damage were the major causes of early death (< 100 days), whereas infection and chronic rejection were primary causes of later death after pulmonary transplantation. By multivariate analysis, cytomegalovirus mismatching risk for primary infection was the most significant risk factor for death, rejection, and infection. Absence of cytomegalovirus prophylaxis was also a risk factor for early and late death and late infection. Survival of recipients who received cytomegalovirus prophylaxis was significantly improved. Immunosuppression based on cyclosporine versus FK 506 was a risk factor for late death and late infection. Graft failure manifested by diffuse alveolar damage/adult respiratory distress syndrome was a significant risk for death late after transplantation. These data suggest the following: (1) The hazard for death, infection, and rejection after pulmonary transplantation appears biphasic; (2) lower survival is associated with ischemia-reperfusion lung injury represented by diffuse alveolar damage/adult respiratory distress syndrome; (3) cytomegalovirus mismatch, absence of cytomegalovirus prophylaxis, and development of cytomegalovirus disease are significant threats for death, rejection, and infection after pulmonary transplantation; (4) prevention of cytomegalovirus disease should improve survival by decreasing the prevalence of infection and rejection.

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Aldo Iacono

University of Maryland

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B. Griffith

University of Pittsburgh

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