The use of micro-dose aprotinin with continuous infusion in coronary artery bypass surgery

BACKGROUND

To evaluate the efficacy of aprotinin at a dose far less than standard.

METHODS

EXPERIMENTAL DESIGN

Retrospective, case-control study.

SETTING

community-based, teaching hospital

PATIENTS

one hundred one patients undergoing primary, non-emergent, coronary artery bypass during two, six-month periods were studied.

INTERVENTIONS

during the first period aprotinin was not administered, and these patients served as controls (n = 52). During the second period all patients received aprotinin via a micro-dose regimen (n = 49).

MEASURES

postoperative bleeding and blood product usage served as determinants of efficacy.

RESULTS

A significant difference existed in postoperative bleeding with the mean thoracic drain outputs being reduced in the aprotinin group both at 6 hours (p = 0.0003) and in total (p = 0.0004). This was further supported by significantly higher hematocrits (p = 0.03) on the first postoperative day in patients receiving aprotinin. Likewise, there was a significant reduction in total blood product exposures (p = 0.04) and platelet usage (p = 0.02) in the aprotinin group with a tendency towards decreased red cell usage. Further, when all patients with a hematocrit < or =30% prior to bypass were excluded, the significant reduction in total blood product exposures persisted (p = 0.04), and there was a significant reduction in red cell usage (p = 0.04) with a trend towards decreased platelet usage (p = 0.06) in the aprotinin group.

CONCLUSIONS

Micro-dose aprotinin significantly reduces postoperative bleeding and blood product usage in primary, non-emergent, CABG patients.

Inflammatory bowel disease

IBD results from the interaction of genetic and environmental factors (e.g., smoking). Clinical suspicion is the key to diagnosis, which then rests on colonoscopy, histopathological examination of multiple biopsy specimens, small bowel barium radiology and faecal examination. The primary goal of treatment is remission--histological in ulcerative colitis and symptomatic in Crohn's disease. Treating active disease and maintaining remission require different approaches. For active disease, short term corticosteroids are the mainstay of treatment, while immunosuppressive drugs are important in chronically active disease. For maintenance, mesalazine-delivering drugs and immunosuppressive agents are efficacious in both ulcerative colitis and Crohn's disease; patients with Crohn's disease should not smoke.

Time-related analysis of nonfatal heart valve complications: cumulative incidence (actual) versus Kaplan-Meier (actuarial)

BACKGROUND

The cumulative incidence of a postoperative event is the percentage of patients who experience the event by postoperative time T. Its complete determination requires all patients to be followed until T. In ongoing series, the Kaplan-Meier method is employed because not all patients have been observed until T. When applied to nonfatal events, however, the Kaplan-Meier estimates probabilities as if the patients who die before they sustain an event continue to be at risk thereafter. It thus estimates risk in the unrealistic situation where death does not occur.

METHODS AND RESULTS

Cumulative incidence can be estimated directly, to provide the probability of actually experiencing an event before death, that is, when death properly eliminates patients from further risk of the event. We compare cumulative incidence and Kaplan-Meier estimates in two series of mitral valve replacement patients: thromboembolism in a completed series of ball valves implanted in relatively young patients and valve explant in an ongoing series of porcine valves in older patients. Kaplan-Meier estimated a higher event percentage than the cumulative incidence, and the difference was greater in the older patients, who had a higher death rate.

CONCLUSIONS

Cumulative incidence, unlike Kaplan-Meier, provides estimates of the percentage of patients who will actually sustain an event. Cumulative incidence is more meaningful for individual patient counseling and more useful for estimating resource utilization in a managed population.

Beta blockade to prevent atrial dysrhythmias following coronary bypass surgery

BACKGROUND

Atrial fibrillation and atrial flutter (AF) frequently complicate coronary artery bypass surgery (CABG) and increase hospital stay as well as morbidity. Studies of drug prophylaxis to prevent AF with beta-adrenergic blocking agents administered in fixed doses have had conflicting results.

METHODS

One hundred patients were randomized to receive metoprolol or placebo following CABG. A dosing algorithm was used to achieve clinically significant beta-adrenergic blockade.

RESULTS

There was no significant difference between the incidence of AF in the metoprolol (24%) and placebo (26%) groups. However, the incidence of AF in all patients having CABG at this institution declined over the period of the study from 31% to 23% (P < .025), in association with the adoption of a continuous technique of cardioplegia delivery.

CONCLUSIONS

Metoprolol is not efficacious for the prevention of post-CABG AF even when dosage is titrated to achieve clinical evidence of beta blockade. It is likely that the adoption of a continuous cardioplegia technique caused a reduction in our incidence of post-CABG AF.

The shift toward a managed care environment in a multispecialty group practice model. Looking for reciprocal benefits

Managed care is notably affecting the practice of surgery in the United States. Four principal elements are subject to change: (1) patient care patterns, (2) ethics, (3) education and research, and (4) surgeon compensation. The Virginia Mason Clinic, a multispecialty group practice, is adapting to the demands of managed and capitated care. With the patient as the primary focus of effort, the goal is to create optimum value in health care. The principles of Continuous Quality Improvement are used to increase value in health care by ensuring appropriate treatment with optimum outcome at reasonable cost. Practice patterns are shifting to provide value to patients and payers. Ethical conflicts threaten but have been avoided. Surgical education remains unaffected, but future funding is problematic. The emphasis in surgical research has shifted toward outcome-based studies. The conflict between work effort and resource conservation as determinants of physician compensation is less for surgical than for medical practitioners. Although the principal benefactors of the shift toward managed care have been the payers, patients have gained modestly through efficiencies in the health care process and more stable insurance premiums. The satisfaction level of the surgeons in our multispecialty group practice remains high. Surgical research is thriving, volumes and case mix remain excellent, and changes in practice pattern have enabled us to increase efficiency without compromising patient care.

Hospitalisation for adverse events related to drug therapy: incidence, avoidability and costs

OBJECTIVES

To determine the incidence of hospital admissions for adverse events related to drug therapy, and to assess whether these drug-related admissions (DRAs) could have been reasonably prevented.

SETTING

A tertiary teaching hospital.

DESIGN AND PATIENTS

Prospective assessment of all admissions through the emergency department and resulting in a stay of more than 24 hours during 30 consecutive days in November and December 1994 to determine if the admission was related to drug therapy. Cases of intentional overdose were excluded.

MAIN OUTCOME MEASURES

The number, type, causality and avoidability of drug-related admissions.

RESULTS

Of 965 admissions, 55 (5.7%) were assessed as being drug-related. Drug-related admissions (DRAs) were designated possibly (38%), probably (46%) or definitely (16%) drug-related; caused by prescribing factors (26%), patient noncompliance (27%) and adverse drug reactions (47%); and classified as definitely (5.5%), possibly (60.0%) and not (34.5%) avoidable. The estimated annual cost to the hospital for all DRAs was $3,496,956 and for unavoidable DRAs was $1,629,494.

CONCLUSION

The DRA rate we found lies around the middle of the range of other published rates. Few DRAs were judged definitely avoidable and over one-third were unavoidable. Nevertheless, the largest proportion were judged possibly avoidable. As the drugs identified in this study are clearly needed in the community, efforts to reduce DRAs must concentrate on education, counselling and monitoring of drug therapy.

Volume requirements for cardiac surgery credentialing: a critical examination. The Ad Hoc Committee on Cardiac Surgery Credentialing of The Society of Thoracic Surgeons

New volume requirements for coronary artery bypass grafting are being imposed on cardiac surgeons by hospitals, managed care groups, and others. The rationale for this is unclear. The available literature as well as additional sources relating volume and outcomes in cardiac surgery were extensively reviewed and reexamined. There are no data to conclusively indicate that outcomes of cardiac operations are related to a specific minimum number of cases performed annually by a cardiac surgeon. Each cardiothoracic surgeon should participate in a national database that permits comparison of his or her outcomes on a risk-adjusted basis with other surgeons. Until conclusive data become available that link volume to outcome, volume should not be used as a criterion for credentialing of cardiac surgeons by hospitals, managed care groups, or others. Instead, each surgeon should be evaluated on his or her individual results.

Thoracic Surgery Workforce Report. The fourth report of the Thoracic Surgery Workforce Committee of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons

To determine demographics, practice patterns, and work volume of North American thoracic surgeons, we sent a detailed survey to all members of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons between January and May 1993 to determine data for 1992; 3049 of 3487 (87%) thoracic surgeons responded and 2677 (88%) were in active practice. Ninety-seven percent were male and 3% female, with a mean age of 52 years. Sixty-five percent considered fee-for-service as their primary compensation mode. Only 24% do isolated subspecialty work: 2% pediatric cardiac surgery. 10% general thoracic surgery, and 12% adult cardiac surgery. Seventy-six percent of respondents do both cardiac and thoracic operations. Workload data for adult cardiac, pediatric cardiac, general thoracic, peripheral vascular, and pacemaker operations were requested. Volume data were cross-correlated with age, 10 geographic regions including Canada, type of practice, and type of compensation and were cross-checked by hospital discharge data for 1992. These data were compared with data from similar surveys performed in 1976, 1980, and 1985, under the auspices of the same two societies; these latter surveys used diplomates of the American Board of Thoracic Surgery as their database. Workloads have increased over previous surveys. Most surgeons do a wide variety of thoracic operations, and exclusive designations are in the minority.

Amphotericin B toxicity reduced by administration in fat emulsion

OBJECTIVE

To report a patient with intolerance to amphotericin B reversed by preparing the antifungal in fat emulsion 20% and to review the medical literature on innovative formulations of amphotericin B.

CASE SUMMARY

A 51-year-old man diagnosed with acute myelogenous leukemia was treated with standard induction chemotherapy. Empiric antibiotic therapy was initiated 2 days postchemotherapy; however, the patient continued to be febrile until day 7. At this time amphotericin B 35 mg/250 mL D5W over 4 hours was administered. Despite premedication, the patient experienced severe rigors, chills, and fever. As the result of continuing infusion-related adverse events, the patient refused further therapy after the third daily dose. In an attempt to reduce the infusion-related events, a trial of amphotericin B 35 mg/35 mL of fat emulsion 20% was administered over 2 hours after patient consent was obtained. Premedication was administered and the patient tolerated therapy without adverse events. Amphotericin B dosage escalations to 50 and 70 mg were tolerated similarly. During this treatment the patient became afebrile and the serum creatinine concentration decreased to normal.

DISCUSSION

Despite significant toxicities and the development of newer antifungal agents, amphotericin B remains the drug of choice for the empiric coverage of suspected fungal infection in neutropenic patients. Amphotericin B often exacerbates the nephrotoxicity of other agents characteristically prescribed in these patients. Furthermore, infusion-related events, if not intolerable, can dramatically reduce the patient's quality of life. For these reasons, novel means of amphotericin B administration are being explored.

CONCLUSIONS

The delivery of amphotericin B in a lipid diluent may have substantial benefit in reducing the nephrotoxicity and infusion-related events associated with the antifungal. Prospective clinical trial comparing lipid-complexed amphotericin B with liposomal and approved formulations of amphotericin B are essential to define potential differences in toxicity and efficacy.

Treatment of calcified cephalohematoma

This is a case report concerning the surgical treatment of a calcified cephalohematoma, which was possibly caused by an intrauterine fetal monitor. This is the first report of this particular entity as a complication of an intrauterine fetal monitor. As far as we can determine, there is no detailed information available about surgical decision making or surgical techniques for removing such lesions. We operated because of the size and persistence of the lesion. We developed a procedure in which we used the bony cap of the cephalohematoma for a cranioplasty, securing it with microplates.

Systematic survey of opinion regarding the thoracic surgery residency

To summarize this rather wide-ranging study, let us review the high points. The future practice of thoracic surgery will be increasingly affected by governmental factors and will have even greater technological dimensions. To do this work, we must continue to attract high-caliber individuals, and this is best accomplished by the early and continuing involvement in the educational process of strong role models from our field. These future surgeons must be motivated to do good work and should have high ethical standards as well as maturity and high intelligence. Experienced, involved faculty leading the residents through a broad program that offers graduated assumption of clinical and leadership responsibilities will facilitate the development of mature clinical judgment. Residents must be taught the clinical skills necessary to do all thoracic operations, leaving subspecialization to postresidency fellowships. The educational program should be humane in its demands and collegial in its application. It should incorporate experiences beyond the operating room, including the opportunity to read, think, and interact with local mentors and colleagues from around the country. The requirements of certification should not be so rigid as to preclude the development of different pathways to the same end. Likewise, although the accreditation process must protect the resident from exploitation, it must not be so restrictive that it does not allow for educational innovation and justifiable differences among programs. These are the thoughtful opinions of our colleagues. They deserve serious consideration.

Selection of patients for same-day coronary bypass operations

Between March 15, 1990, and December 31, 1991, we admitted to the Virginia Mason Hospital for isolated coronary bypass operations 175 consecutive patients with chronic, stable angina pectoris who had prior coronary arteriography. One hundred patients were admitted on the same day as their operations, and 75 patients, deemed to be at higher risk, were admitted 1 day before the operation. Postoperative progress of all patients was monitored by means of a clinical pathway form with physiologic and activity measures plotted against postoperative days. We found no difference in age, sex, or total number of comorbidity factors. Diabetes and ejection fraction less than 0.50 were significantly more common in preoperatively admitted patients and were independently predictive of admitting group. Significant differences between surgeons in the proportion of same-day patients admitted could not be explained by differences in common risk factors. There was no significant difference in postoperative major or minor complications or number of clinical pathway deviations, but two deaths occurred in patients admitted preoperatively. Average total hospital stay was 1 1/2 days less for same-day patients, a highly significant difference. Total hospital charges averaged $19,000 for the series and were $286 more for preoperatively admitted patients, a difference that was not statistically significant. Patients admitted selectively for same-day coronary bypass are not at risk for an increased number of complications. Although their hospital stay is reduced, the reduction of their hospital charges is minimal. Preoperative admission of patients with comorbidity requiring medical management or with physical incapacity remains justified, and admitting decisions should remain with the operating surgeon, not third parties.

Pharmacy-coordinated, multidisciplinary adverse drug reaction program

To date, the stated program objectives have been met. There is a heightened awareness of ADRs, and the program has had a positive impact on patient care. More work is needed in the prevention of ADRs as opposed to their tabulation. Future educational efforts will focus on how reporting suspected ADRs can positively impact patient care.

Mitral valve reconstruction

Modern repair techniques allow reconstruction rather than replacement of the mitral valve (MV) in the majority of patients requiring operation. Such patients are now older and more likely to have nonrheumatic MV disease than those treated in former years. A continuing experience with MV reconstruction was reviewed to determine its safety and efficacy. In 50 patients undergoing isolated MV reconstructions, there have been no postoperative deaths. In 36 patients undergoing mitral reconstruction combined with other cardiac procedures, there have been 5 deaths (14%). Three patients have required MV replacement for an inadequate repair as determined by evaluation during the repair or by intraoperative transesophageal echocardiography (TEE) following cardiopulmonary bypass. Overall complications have included five reoperations for bleeding, two perioperative myocardial infarctions, two strokes, and one aortic dissection. The majority of patients maintain an improved functional state after operation. Multiple reconstructive maneuvers are now available, and the elements of any given reconstruction depend on the pathoanatomy of the valve. Intraoperative TEE has been invaluable in planning, evaluating, and modifying repairs. At present, over 70% of all MV operations are reconstructions, and the most common recent indication for MV replacement is a malfunctioning prosthetic MV rather than native valve disease.

Continuing experience with the automatic implantable cardioverter defibrillator

The automatic implantable cardioverter defibrillator (AICD) is now used commonly in the management of malignant ventricular arrhythmias. Its use may obviate the need for antiarrhythmic drugs or endocardial resection. We reviewed our continuing experience with the AICD to determine its safety and efficacy. Since June 1987, 102 patients (mean age: 63 years) who survived out-of-hospital ventricular fibrillation or hemodynamically unstable ventricular tachycardia not associated with acute myocardial infarction underwent implantation of an AICD. There were three operative deaths and nine complications. Eighty-nine patients are alive. No patient has experienced sudden cardiac death. Forty-two patients (43%) have had 1 or more AICD discharges associated with symptoms of cardiac arrest. During AICD implantation, it appears preferable to configure lead placement by individual patient characteristics rather than by a rigid protocol. The relative safety and efficacy of the AICD support its use as an alternative to toxic medications or more dangerous endocardial resection in suboptimal candidates.

Hepatobiliary excretion of bacterial formyl-methionyl peptides in rat. Structure activity studies

The bacterial chemotactic peptide formyl-met-leu-phe and its radioiodinated analog formyl-met-leu-[125I]tyr are rapidly excreted by the liver into bile following portal or systemic venous infusions in rats or after absorption from the gut lumen. To determine the molecular structural requirements for hepatobiliary excretion of formyl-methionyl peptides, structure-activity studies using portal venous infusions of 24 structural analogs of formyl-met-leu-tyr were performed in rats with biliary cannulae. Hepatic extraction of peptides was studied in vivo using external gamma counting after portal infusion. Efficient hepatobiliary excretion was not restricted to bioactive formyl peptides, but showed a broad specificity for different amino-acylated (formyl, acetyl, propionyl, carbobenzoxy) di- and tripeptides and no requirement for methionine in position one or for a free carboxy terminus. However, nonacylated peptides and an acyl-amino acid showed little excretion. Hepatic extraction of peptide was also related to N-acylation. Hepatic extraction and excretion of N-acyl peptides were also related to hydrophobicity. Thus, the presence of an N-acyl group is the key determinant of biliary excretion of inflammatory bacterial f-met peptides in the rat.

Routine computed tomographic scans, selective mediastinoscopy, and other factors in evaluation of lung cancer

Routine computed tomographic scan is advocated as the best noninvasive method of evaluating mediastinal nodes for cancer spread. Positive studies should be confirmed histologically. Large size, central location, unfavorable cell type, poor cellular differentiation of the primary cancer, and weight loss also correlate with increased likelihood of mediastinal involvement.