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Biomedical subjects

R W Emery

Publications and source records attributed to R W Emery.

At least 37 records · Page 2Linked to original sources
PubMed1998

Clinical evaluation of the on-line Sensicath blood gas monitoring system.

BACKGROUND: Blood gas analysis is an integral part of the management of open heart surgery and post-surgical intensive care patients. This study was conducted to compare the results of on-line blood gas analysis using the new Sensicath (SC) optical sensor technology against standard blood gas assay. METHODS: Comparative blood gas analysis was performed on 45 postoperative cardiovascular surgical patients and 5 patients during cardiopulmonary bypass. Simultaneous samples were obtained. One sample was sent to the central hospital laboratory for measurement using a Radiometer ABL 500 blood gas analyzer and the second sample was drawn past the optical sensor. Comparisons between the two methods for pH, pO2 and pCO2 were analyzed using linear regression and the method of Bland and Altman for the intensive care unit samples (N = 451) while the T test was used to compare data points obtained during cardiopulmonary bypass (N = 57). Bias, accuracy and precision were also calculated. RESULTS: The regression lines (r2) for pH, pO2, and pCO2 and were 0.69, 0.94, and 0.68 with slopes of 1.000, 0.0957, and 1.052 respectively for postoperative surgical patients. During cardiopulmonary bypass, the T test did not show any significant difference between the Sensicath and the reference values for the arterial and venous pH, pO2 and pCO2. CONCLUSIONS: In summary, this study found the Sensicath to be an accurate, useful tool which permits immediate blood gas analysis without blood exposure and constitutes an advance in the field of intensive care monitoring.

Blood Gas Analysis↗
PubMed1997

Minimally invasive direct coronary artery bypass grafting: experimental and clinical experiences.

BACKGROUND: This communication briefly details the goals, indications, surgical approaches, and limitations of minimally invasive direct coronary artery bypass grafting (MIDCABG). The experimental experiences from various institutions are summarized. METHODS: The clinical experiences of 72 consecutive MIDCABG procedures performed at our institutions between June 5, 1995, and August 13, 1996, were analyzed. We have divided patients into two groups. Group A consists of healthy low-risk patients with single lesions of the left anterior descending coronary artery or the right coronary artery, or with both lesions of both arteries. Group B consists of high-risk patients who had major contraindications to conventional cardiopulmonary bypass procedures. There were 55 patients in group A and 17 patients in group B. Using The Society of Thoracic Surgeons preoperative predicted risk module, group A had a 1% predicted mortality versus 4% in group B. RESULTS: The 30-day mortality was 2% in group A and 6% in group B. The mean postoperative length of stay was 4 days for group A and 5 1/2 days for group B. Short-term follow-up of the survivors appears promising, and 81% of patients were angina free at the time of last follow-up. CONCLUSIONS: The MIDCABG techniques are still developing. The short-term results during the learning period appear to be quite good, but long-term results remain yet to be seen. The addition of new equipment to facilitate construction of the anastomosis will enhance application and results. The lessons learned from these approaches are already being applied to other areas of cardiac surgery including valve replacement and the repair of congenital heart defects.

Coronary Artery Bypass↗
PubMed1997

Evaluation of 7,000+ patients with two different routes of cardioplegia.

BACKGROUND: This study examined the efficacy and safety of retrograde cardioplegia in comparison with an antegrade/retrograde approach. METHODS: Between January 1, 1991, and December 31, 1995, 7,032 coronary artery bypass procedures, alone or in combination with valve replacement/repair, were performed using either retrograde cardioplegia (R) or an antegrade/retrograde (AR) approach. There were 4,224 patients in the R group and 2,808 in the AR group. These included elective, urgent, emergent/salvage, first operative, and redo cases. RESULTS: All preoperative, intraoperative, and postoperative variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to compare the two groups using univariate analysis. The pump time was longer in the AR group, with fewer grafts per patient. The R group had higher predicted risk (3.2% versus 3.0%; p = 0.04), more postoperative atrial fibrillation (34% versus 31%; p = 0.006), and longer postoperative length of stay (8.8 versus 8.0 days; p < 0.001). Using The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group model, a subgroup of 221 coronary artery bypass grafting patients in the retrograde (s-R) and 132 coronary artery bypass grafting patients in the antegrade/retrograde (s-AR) group fell into a greater incidence of predicted mortality group (> or = 10%). The s-R subgroup had more patients in New York Heart Association functional class IV. Univariate analysis revealed higher postoperative atrial fibrillation (51% versus 41%; p = 0.05) and longer postoperative length of stay (12.8 versus 10.8 days; p = 0.03) in the s-R subgroup versus the s-AR subgroup. CONCLUSIONS: The results appear to favor neither approach. Preoperatively, both retrograde groups (R and s-R) had higher preoperative predicted risk, but operative mortality or complications were not significantly increased when compared with the AR and s-AR groups. Retrograde cardioplegia alone was shown to be effective in the R and s-R groups, but atrial fibrillation developed in more patients, which could have contributed to longer length of stay in these groups. Antegrade/retrograde cardioplegia offers good immediate outcome but the delivery method can be cumbersome and confusing during the adjustments of flow clamps for antegrade/retrograde delivery and may contribute to prolonged pump times. From this retrospective, nonrandomized review, it appears that retrograde cardioplegia alone provides as good myocardial protection and safety as an antegrade/retrograde approach in either the low-risk or high-risk patient.

Atrial Fibrillation↗
PubMed1997

The MIDCAB experience: a current look at evolving surgical and anesthetic approaches.

This article reviews and updates the recent modifications in patient selection and revisions in the anesthetic approach to MIDCAB surgery. It outlines the changing surgical selection criteria, current ways to assess graft patency, and evolving anesthetic management. A promising new advancement in coronary artery bypass, the minimally invasive technique has received varying reviews and undergoes careful evaluation. Increasing surgical experience, immediate postoperative assessment of graft patency, and improvement in surgical instruments are expected to improve patient outcome. A stratification of MIDCAB patients into status I and status II patients will aid in future evaluation of surgical and anesthetic outcome. Communication of newly developed techniques to those caring for cardiovascular patients is imperative.

Anesthesia↗
PubMed1997

Policies regarding the transplantation of hepatitis C-positive candidates and donor organs.

Whether hepatitis C virus (HCV)-positive candidates or donor organs should undergo transplantation remains controversial. Seventy-two thoracic transplantation centers responded to a survey soliciting specific information about policies regarding the listing of HCV-positive candidates and the use of HCV-positive donor organs. Most centers (64%) list HCV-positive candidates for heart transplantation. Twenty-six percent of centers refuse to use HCV-positive organs, whereas the remainder restrict the use of HCV-positive organs to status 1 recipients or HCV-positive candidates. More information is needed regarding the clinical outcomes of HCV-positive candidates and recipients of HCV-positive organs before clear-cut candidate selection and organ allocation policies can be established.

Ethics, Medical↗
PubMed1996

Patient characteristics, safety, and benefits of same-day admission for coronary artery bypass grafting.

BACKGROUND: The move toward outpatient and same-day surgery has been phenomenal in the past several years. Efforts in this area have focused on limiting inpatient hospitalization, reducing ancillary services, and decreasing length of stay. METHODS: Two hundred seventy-six DRG 107 patients who were operated on at our institutions in 1994 and registered in The Society of Thoracic Surgeons National Cardiac Surgery Database were reviewed. There were 185 patients randomly admitted to the hospital on the day of operation and 91 patients admitted 1.78 +/- 1.94 days before. These patients were analyzed according to The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group and expected operative mortality modules. Univariate analysis of all risk variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to identify the difference between 176 elective procedure patients in the same-day admission group and 67 elective procedure patients in the non-same-day admission group. RESULTS: The same-day admission group had lower expected operative mortality (1.3% versus 2.9%), fewer female patients (17% versus 29%), younger age (62 versus 67 years), and fewer patients in the higher predicted risk group. Univariate analysis showed only age and ejection fraction variables were significantly different between the two elective groups. Comorbidities predictive of elective non-same-day admission revealed that age and New York Heart Association class IV were significant predictors. The length of stay was shorter and the total charges were less in the same-day admission group. CONCLUSIONS: There was no increase in preoperative, intraoperative, or postoperative complications in the same-day admission patients. Same-day admission was safe and cost-effective and could be carried out as a routine admission for several selected groups of patients.

Aged↗
PubMed1996

Mini-sternotomy for coronary artery bypass grafting.

This communication details the approach to the left anterior descending artery, right coronary artery, or both via a single limited incision of the chest. The mini-sternotomy incision is 10 to 12 cm long. The distal anastomosis can be accomplished, with a beating heart, through this small incision, with or without cardiopulmonary bypass.

Cardiopulmonary Bypass↗
PubMed1996

North American experience with the Perma-Flow prosthetic coronary graft.

BACKGROUND: The Perma-Flow prosthetic coronary graft is a 5-mm polytetrafluoroethylene tube into which is incorporated a Venturi flow restrictor. An aorto-superior vena caval fistula is created and coronary anastomoses are constructed proximal to the resistor in side-to-side fashion, where arterial pressure is maintained. From November 1992 through December 1995, eight investigational centers in North America have implanted this graft in 40 patients with inadequate autologous alternatives. METHODS: Patients were selected for inclusion in this study if coronary artery bypass grafting was required and adequate autologous conduit to complete revascularization was not available. Operative data were completed by the implantating surgeon and referred to a central center, the Minneapolis Heart Institute, for correlation. Follow-up was conducted by data coordinators at each institution, and follow-up data were obtained directly from these coordinators for inclusion in the study. RESULTS: Patient age ranged from 53 to 82 years, and 15 patients were undergoing reoperations (38%). On each Perma-Flow graft one to four coronary side-to-side anastomoses were constructed. In addition, left internal mammary artery (n = 26), greater saphenous vein (8), right internal mammary artery (4), and gastroepiploic artery (4) were used to complete revascularization. Aortic (2) or mitral valve replacement (1) was also carried out. There were seven operative deaths (18%) and two late deaths (4 and 6 months). After 1 to 37 months (mean, 13 +/- 9 months) of follow-up, 29 of 31 surviving patients are asymptomatic. Echocardiographic heart size has not increased from the postoperative value, indicating limited volume load has not affected heart size. Protocol catheterization (n = 32) in 28 patients 1 week to 1 year postoperatively revealed 7 of 73 studied coronary anastomoses (9.5%) and two distal extensions and resistors were occluded (7%). In 1 patient during sternal debridement at 1 year, no flow was found in the graft. CONCLUSIONS: The Perma-Flow graft is a useful adjunct to complete revascularization in patients with deficient autologous conduit.

Aged↗
PubMed1996

Revascularization using angioplasty and minimally invasive techniques documented by thermal imaging.

Minimally invasive direct coronary artery bypass grafting offers mortality and morbidity advantages to selected patients. To broaden indications for such, an appropriate and combined disciplinary approach using angioplasty and minimally invasive direct coronary artery bypass grafting is described in a patient requiring reoperative grafting. Documentation of patency of new left internal mammary artery-to-left anterior descending artery anastomoses performed without the use of cardiopulmonary bypass was obtained intraoperatively using a Thermal Imaging Camera.

Aged↗
PubMed1996

Utilization of the St. Jude Medical prosthesis in the aortic position.

Intensive in vitro and in vivo studies led to the clinical introduction of the St. Jude Medical (SJM) prosthesis in October 1977. Because of excellent clinical characteristics, handling, and durability, as well as the low incidence of clinically adverse events, the SJM valve has become the most commonly used prosthetic heart valve. In 1,431 patients undergoing aortic valve replacement during a 15-year period, the incidence of clinically adverse events, including thromboembolism, thrombosis, paravalvar leak, reoperation and anticoagulant-related hemorrhage, have been less than 0.8% per patient-year in both adult and pediatric patients. There have been no structural failures. The SJM prosthesis is an excellent device for the treatment of diseases of the aortic valve.

Adolescent↗
PubMed1996

Anticoagulant related complications in elderly patients with St. Jude mechanical valve prostheses.

BACKGROUND AND AIMS OF THE STUDY: This communication reports the anticoagulant-related complications (ARH) in patients who received the St. Jude Medical mechanical prosthesis and were 70 years of age or older at the time of implantation. METHODS: Our institutional data file shows that during the 15-year period from 1977 to 1992, our group implanted the St. Jude Medical mechanical prosthesis in 610 patients with aortic valve disease (AVR) and 186 patients with mitral disease (MVR), who were 70 years or older, either with or without coronary artery bypass grafts. The operative mortality was 6.4% for AVR and 16% for MVR. The mean follow up for this elderly group was 4.9 years (2,996 patient-years) for AVR and 4.2 years (771 patient-years) for MVR. RESULTS: The incidence of late death was 30% for AVR and 33% for MVR. The freedom from TE was 91.6% +/- 1.8%, from valve thrombosis 98.8% +/- 0.7%, and from ARH 95.9% +/- 1.1%. The freedom from operative death, valve-related death, and all complications was 78.8% +/- 2.4%. The data from this study shows that both the aortic and the mitral valve replacement patients who were 70 years or older have an acceptable rate of bleeding complications. Reduction of the intensity of anticoagulation in our practice (INR of 1.8-2.5 for AVR and 2.5-3.2 for MVR) may play a role in this finding. The incidence of valve thrombosis and TE rates were also low in this study. CONCLUSIONS: With increasing life expectancy in the elderly, the use of the St. Jude Medical Mechanical prosthesis and low intensity anticoagulation could be reconsidered for a selected group of elderly patients.

Aged↗
PubMed1995

Long-term follow-up of the St. Jude Medical prosthesis in pediatric patients.

BACKGROUND: The St. Jude Medical prosthesis has become the most commonly used artificial heart valve, yet few data are available in the pediatric population. This study addresses results of the use of this prosthetic valve in pediatric patients over a 13-year time frame. METHODS: From January 1982 through June 1994, 73 patients (49 male) underwent 75 valve replacements using the St. Jude Medical prosthesis at Minneapolis Children's Medical Center. Follow-up was complete in 71 patients, with a mean follow-up of 39 +/- 32 months (mean +/- standard deviation; range, 4 to 142 months). RESULTS: Valves' positions were aortic in 36 patients, mitral or left atrioventricular valve in 34, tricuspid in 1, and double valve in 2. Patient age was 8 +/- 6 years, with a range of 1 week to 19 years. Sixteen patients were less than 24 months of age at valve replacement. Prior cardiac procedures had been performed in 82% of mitral patients, 58% of aortic patients, and all of the tricuspid and double-valve patients. Elective valve replacement was performed in 62 to 73 patients (85%). Seven patients (44%) less than 24 months of age had urgent valve replacement; 4 patients (7%) older than 24 months required urgent valve replacement. Overall early mortality was 8% (6 of 73); 36% (4 of 11) in the patients undergoing urgent valve replacement and 3% (2 of 62) in the elective group. All but one of the deaths were due to cardiac dysfunction. There were four late deaths, from 4 to 125 months postoperative, primarily caused by congestive heart failure or pulmonary vascular disease. Cumulative freedom from valve-related events was 93%, 85%, and 77% at 1, 5, and 10 years, respectively. Valve-related complications included thromboembolism (4), bleeding (5), perivalvar leak requiring reoperation (2), transient ischemic attack (1), and endocarditis (1). There have been no permanent strokes or mechanical malfunction. The majority of patients are currently managed with warfarin. Five surviving patients whose initial valve replacement was at age 24 months or younger have undergone repeat valve replacement (42%). Ninety-five percent of patients enjoy good health at follow-up. CONCLUSIONS: The St. Jude Medical prosthesis offers correction of valvular disease with low morbidity and mortality, and excellent functional result.

Adolescent↗