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Biomedical subjects

A A Bove

Publications and source records attributed to A A Bove.

At least 19 recordsLinked to original sources
PubMed2001

Pulmonary edema associated with scuba diving : case reports and review.

Acute pulmonary edema has been associated with cold-water immersion in swimmers and divers. We report on eight divers using a self-contained underwater breathing apparatus (scuba) who developed acute pulmonary edema manifested by dyspnea, hypoxemia, and characteristic chest radiographic findings. All cases occurred in cold water. All scuba divers were treated with complete resolution, and three have returned to diving without further episodes. Mechanisms that would contribute to a raised capillary transmural pressure or to a reduced blood-gas barrier function or integrity are discussed. Pulmonary edema in scuba divers is multifactorial, and constitutional factors may play a role. Physicians should be aware of this potential, likely underreported, problem in scuba divers.

Acute Disease↗
PubMed1999

Infraorbital hypesthesia after maxillary sinus barotrauma.

We report a case of a diver who suffered an episode of maxillary sinus barotrauma that presented with decreased sensation over the cutaneous distribution of the infraorbital nerve after an ascent which produced facial pain and crepitus. This case illustrates a potential confusion between a decompression sickness etiology and a barotraumatic etiology for the observed sensory deficit. The clinical features of this case were most consistent with a barotraumatic etiology for the findings noted. The anatomy of the trigeminal nerve and previous reports of cranial nerve deficits following barotrauma are reviewed.

Barotrauma↗
PubMed1998

Current knowledge and significance of coronary artery ectasia: a chronologic review of the literature, recommendations for treatment, possible etiologies, and future considerations.

Coronary artery ectasia is the abnormal enlargement of the coronary artery. The prognosis, treatment, and etiology of this disease remain an enigma. There is some evidence to suggest that the incidence of ectasia is increasing, and therefore understanding of this entity needs to improve. This article reviews the current literature on coronary artery ectasia and summarizes the findings. A treatment plan that targets each of the suggested clinical complications is provided. Using multiple indirect observations and current understanding of endothelium-derived relaxation factor, a possible etiology that implicates overstimulation of endogenous nitric oxide is provided. Current literature suggests that ectatic coronary arteries, even without the presence of coronary stenosis, are subject to thrombus formation, vasospasm, and spontaneous dissection. Newer subgroups of ectasia are arising with the use of multiple interventional devices to dilate coronary artery stenosis. By design, these destroy the media of the coronary artery, and it is not clear whether these "iatrogenic" ectatic arteries are subject to the same complications as "idiopathic" coronary artery ectasia. Further investigation is necessary to help define the benefit of the proposed treatment regimen, to clarify the prognosis of these newer groups of "iatrogenic" ectasia, and to confirm or disprove the hypothesis targeting nitric oxide as an etiologic factor.

Anticoagulants↗
PubMed1998

Risk of decompression sickness with patent foramen ovale.

Several reports have described populations of divers with decompression sickness (DCS) who have a patent foramen ovale (PFO). The presence of a PFO is known to occur in about 30% of the normal population, hence 30% of divers are likely to have a PFO. Although observations have been made on the presence of a PFO in divers with and without DCS, the risk of developing DCS when a diver has a PFO has not been determined. In this study, Logistic Regression and Bayes' theorem were used to calculate the risk of DCS from data of three studies that reported on echocardiographic analysis of PFO in a diving population, some of whom developed DCS. Overall incidence of DCS was obtained from the sport diving population, from the U.S. Navy diving population, and from a commercial population. The analysis indicates that the presence of a PFO produces a 2.5 time increase in the odds ratio for developing serious (type II) DCS in all three types of divers. Since the incidence of type II DCS in these three populations averages 2.28/10,000 dives, the risk of developing DCS in the presence of a PFO remains small, and does not warrant routine screening by echocardiography of sport, military, or commercial divers.

Confidence Intervals↗
PubMed1996

Medical aspects of sport diving.

Medical issues in sport diving include illnesses that are caused by diving, and medical disorders that compromise safety. Cerebral air embolism and decompression sickness of the brain and spinal cord can result from diving. Sport divers may manifest a spectrum of symptoms from air embolism, which can range from unconsciousness to minimal symptoms, which include fatigue, personality change, poor concentration, irritability, and changes in vision. The physician must search for these minor symptoms in divers who are suspected of pulmonary barotrauma. Medical disorders of concern in diving include diseases of the lungs, the heart, the brain, and the endocrine system, particularly diabetes. Other factors involved in diving safety are exercise capacity and training. Clinical practice standards usually prohibit diving by individuals who have a seizure disorder that requires continuous medication. In the United States, we will not approve diving for individuals who have insulin-dependent diabetes or severe asthma. Some divers can return to diving after myocardial infarction or bypass surgery if they demonstrate good exercise tolerance and no ischemia on a graded exercise test, which simulates the physical activity needed for safe diving.

Asthma↗
PubMed1996

Donor-specific HLA antibodies after transplantation are associated with deterioration in cardiac function.

Although there is increasing evidence that mismatched donor HLA antigens are associated with a lowering of survival of human cardiac allografts, the effect of antibodies that bind those antigens is less clear. The existence of lymphocytotoxic antibodies prior to cardiac transplantation has been associated with a poor outcome in the majority of reports of relevant studies, as has their appearance post-transplantation. But how such antibodies, especially those with HLA specificity, cause poor outcomes has been poorly understood. The purpose of this study was to investigate the effect of anti-HLA antibodies appearing in the circulation after human orthotopic heart transplantation. Such antibodies were identified by a standard microlymphocytotoxicity technique using panels of frozen lymphocytes from normal donors who had been tissue typed. Of 74 patients transplanted over a 12-month period, 4 (5.4%) developed alloantibodies specific for mismatched donor HLA antigens. The first patient developed antibodies to HLA-A23 and B44 together with poor ventricular function and vascular rejection requiring retransplantation within 4 months. The other patients (3) developed antibodies specific for HLA-DQ antigens and experienced variable numbers of episodes of cellular rejection with no evidence of vascular rejection on endomyocardial biopsy. Two of these three patients died (8 and 11 months post-transplant) after three and six rejection episodes, respectively. The one surviving patient had seven rejection episodes and continues to have poor ventricular function 18 months post-transplant. We conclude that alloantibodies specific for mismatched donor HLA antigens may have a deleterious effect on the outcome of the human cardiac allograft and should be monitored closely post-transplant. Furthermore, such antibodies may mediate effects on the transplanted heart which are not detectable in specimens obtained by endomyocardial biopsy.

Adult↗
PubMed1995

Effect of thromboxane A2 blockade on clinical outcome and restenosis after successful coronary angioplasty. Multi-Hospital Eastern Atlantic Restenosis Trial (M-HEART II)

BACKGROUND: Antithromboxane therapy with aspirin reduces acute procedural complications of coronary angioplasty (PTCA) but has not been shown to prevent restenosis. The effect of chronic aspirin therapy on long-term clinical events after PTCA is unknown, and the utility of more specific antithromboxane agents is uncertain. The goal of this study was to assess the effects of aspirin (a nonselective inhibitor of thromboxane A2 synthesis) and sulotroban (a selective blocker of the thromboxane A2 receptor) on late clinical events and restenosis after PTCA. METHODS AND RESULTS: Patients (n = 752) were randomly assigned to aspirin (325 mg daily), sulotroban (800 mg QID), or placebo, started within 6 hours before PTCA and continued for 6 months. The primary outcome was clinical failure at 6 months after successful PTCA, defined as (1) death, (2) myocardial infarction, or (3) restenosis associated with recurrent angina or need for repeat revascularization. Neither active treatment differed significantly from placebo in the rate of angiographic restenosis: 39% (73 of 188) in the aspirin-assigned group, 53% (100 of 189) in the sulotroban group, and 43% (85 of 196) in the placebo group. In contrast, aspirin therapy significantly improved clinical outcome in comparison to placebo (P = .046) and sulotroban (P = .006). Clinical failure occurred in 30% (49 of 162) of the aspirin group, 44% (73 of 166) of the sulotroban group, and 41% (71 of 175) of the placebo group. Myocardial infarction was significantly reduced by antithromboxane therapy: 1.2% in the aspirin group, 1.8% in the sulotroban group, and 5.7% in the placebo group (P = .030). CONCLUSIONS: Thromboxane A2 blockade protects against late ischemic events after angioplasty even though angiographic restenosis is not significantly reduced. While both aspirin and sulotroban prevent the occurrence of myocardial infarction, overall clinical outcome appears superior for aspirin compared with sulotroban. Therefore, aspirin should be continued for at least 6 months after coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1995

Functional and morphologic adaptation of undersized donor hearts after heart transplantation.

OBJECTIVES: This study analyzes our experience with transplantation of small donor hearts in a subgroup of moribund patients who could not be bridged to transplantation with mechanical assist devices. BACKGROUND: The major problem facing transplant programs in the United States is the lack of donor heart availability. One method of expanding the donor pool may be to liberalize the criteria for an acceptable donor heart. METHODS: We analyzed the growth and adaptation of 14 undersized and 14 conventionally sized donor hearts over a period of 10 weeks after heart transplantation. The left ventricular systolic and diastolic diameters, septal and posterior wall thicknesses, left ventricular mass calculated by the Penn convention and left ventricular ejection fraction were obtained by M-mode and two-dimensional echocardiography and documented by a single reader in blinded manner. Echocardiographic measurements were obtained before implantation and at 5 and 10 weeks after orthotopic heart transplantation. RESULTS: The mean (+/- SD) donor/recipient weight ratios were 0.53 +/- 0.06 for undersized hearts and 0.98 +/- 0.05 for normal-sized hearts. All 28 patients received similar immunosuppressive regimens, including intravenous steroids, cyclosporine and azathioprine. The length of hospital stay after transplantation did not vary significantly between the two groups. All the patients had at least one rejection episode during the 10-week study period. There was a tendency toward higher pulmonary pressures in undersized hearts, which was not statistically significant. Heart rate was significantly higher for undersized hearts, due in part to the use of theophylline or terbutaline to maintain tachycardia. There was a significant increase in left ventricular systolic and diastolic dimensions in undersized hearts compared with conventionally sized hearts. Undersized hearts increased in left ventricular mass over the 10-week period, whereas the conventionally sized donor hearts did not change between 5 and 10 weeks. CONCLUSIONS: In undersized hearts the increase in left ventricular mass and internal dimensions, with preservation of the posterior/septal wall thickness ratio, suggests that the left ventricle adapts to the larger recipient circulation early after transplantation. Despite denervation and a mismatched load, undersized transplanted hearts adapt appropriately to their new hemodynamic milieu.

Adaptation, Physiological↗
PubMed1995

Medical department operations in a fleet hospital during Operation Desert Storm.

Fleet hospital 15 was deployed to Saudi Arabia in Operation Desert Storm. The facility was a 500-bed echelon-3 hospital located near Al Jubail, which served the fleet marines from February to April 1991. The medical staff of the department of medicine consisted of reserve medical officers with a variety of backgrounds. The desert environment, concern for endemic diseases, limitations of equipment, and the environment of conflict presented challenges to the medical department that required adaptation of civilian skills to this new environment. The hospital served as a community medical center, with 86% of the inpatient and outpatient treatment provided for non-battle-related illness and injury. Design considerations of fleet hospitals for future deployments should include the likelihood of treating a large number of non-battle-related injuries and illnesses.

Community Health Centers↗
PubMed1994

Asthma and diving.

BACKGROUND: Approximately 10 to 15 million Americans are scuba divers. The prevalence of scuba diving and asthma makes it likely some asthmatics will be interested in scuba diving and some scuba divers will have asthma. Conditions present during scuba diving may provoke airway obstruction in asthmatic patients. Further, asthmatic patients may, in theory, face a greater than normal risk of pulmonary barotrauma from lung overdistension on ascent through the water column. OBJECTIVE: The purpose of this paper is to review the theoretical issues underlying the prohibition against scuba diving for asthmatic patients as advanced by most major diving organizations in the United States and critically examine the relevant accident data. METHODS: All reports that dealt with asthma and diving, and all available American accident data including both fatal and nonfatal accidents were reviewed. RESULTS: Actuarial data on the risk of scuba accidents attributable to asthma do not define several important variables likely to affect accident risk during scuba diving. Despite these limitations, careful review indicates the risks of serious morbidity or mortality during scuba diving appears to be inconsequentially elevated in subjects whose asthma was not characterized. CONCLUSIONS: Additional data are needed to define accurately risks of diving in subjects with different forms of asthma, however, the available data suggest asthmatic patients with normal airway function at rest, and with little airway reactivity in response to exercise or cold air inhalation, have a risk of pulmonary barotrauma similar to that of normal subjects.

Airway Obstruction↗
PubMed1994

Adult orthotopic heart transplantation using undersized pediatric donor hearts. Technique and postoperative management.

BACKGROUND: Because of the critical shortage of adult donor hearts, many recipients die awaiting transplantation of an organ of appropriate size. Undersized hearts (donor/recipient weight ratio < 0.7) have been used for heterotopic heart transplantation. We report on 6 moribund adult heart transplant candidates who were rescued with orthotopic heart transplantation of undersized pediatric hearts. METHODS AND RESULTS: Recipients were hypotensive (mean blood pressure, 62.3 +/- 13.4 mm Hg), had high pulmonary artery pressures (mean pulmonary artery pressure, 42.4 +/- 6.3 mm Hg), and had mean cardiac indexes of 1.7 +/- 0.6 L.min-1.m-2. Four had pretransplant intra-aortic balloon pumps, and one was on a Thoratec left ventricular assist device complicated by fungemia. Since conventionally sized donors were unavailable (+/- 30% recipient weight), the patients were listed in a wider weight range (+/- 60%). Donor characteristics were age, 8.7 +/- 1.5 years; weight, 32.8 +/- 7.0 kg; and donor/recipient weight ratio, 0.44 +/- 0.2, with average ischemic time of 236.0 +/- 59.3 minutes. Technical considerations during transplantation included (1) opening the donor right atrium from the inferior vena cava to superior vena cava to facilitate size matching, (2) performing size-mismatched pulmonary artery and aortic anastomoses end to end, (3) infusing prostaglandin E1 12 ng.kg-1.min-1 to decrease pulmonary and systemic vascular resistance, (4) pacing donor and recipient atria synchronously to improve ventricular filling, (5) maintaining high heart rates up to 140 beats per minute (initially with isoproterenol or pacing, chronically with theophylline), (6) hyperventilating with sedation and paralysis as necessary, (7) reperfusing with triiodothyronine, and (8) minimizing afterload. All patients were discharged from the hospital. At 1 week, hemodynamics were normal and echocardiograms demonstrated left ventricular growth. CONCLUSIONS: Hence, undersized pediatric hearts can be used successfully to salvage moribund patients and expand the potential donor pool for adult orthotopic heart transplantation.

Body Constitution↗