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Biomedical subjects

J Varon

Publications and source records attributed to J Varon.

At least 19 recordsLinked to original sources

Hyponatremia, cerebral edema, and noncardiogenic pulmonary edema in marathon runners.

BACKGROUND: Noncardiogenic pulmonary edema is often associated with increased intracranial pressure and can be the initial manifestation of hyponatremic encephalopathy. Marathon runners tend to develop conditions that lead to hyponatremia. OBJECTIVE: To describe the development and treatment of noncardiogenic pulmonary edema in marathon runners that was associated with hyponatremic encephalopathy. DESIGN: Case series. SETTING: One university hospital and two community hospitals. PATIENTS: Seven healthy marathon runners who had a history of nonsteroidal anti-inflammatory drug use. The runners collapsed after competing in a marathon and were hospitalized with pulmonary edema. MEASUREMENTS: Plasma sodium levels, chest radiograph, electrocardiogram, cardiac enzyme levels, and magnetic resonance imaging or computed tomographic scans of the brain. RESULTS: Patients had nausea, emesis, and obtundation. The mean (+/-SD) plasma sodium level was 121 +/- 3 mmol/L, and oxygen saturation was less than 70%. Electrocardiograms and echocardiograms were normal. Chest radiographs showed pulmonary edema with a normal heart. Creatine phosphokinase-MB bands, troponin levels, and pulmonary wedge pressure were not elevated. Scanning of the brain showed cerebral edema. All patients were intubated and mechanically ventilated. Treatment with intravenous NaCl, 514 mmol/L, increased plasma sodium levels by 10 mmol/L in 12 hours. Pulmonary and cerebral edema resolved as the sodium level increased. One patient had unsuspected hyponatremic encephalopathy and died of cardiopulmonary arrest caused by brainstem herniation. All six treated patients recovered and were well after 1 year of follow-up. CONCLUSIONS: In healthy marathon runners, noncardiogenic pulmonary edema can be associated with hyponatremic encephalopathy. The condition may be fatal if undiagnosed and can be successfully treated with hypertonic NaCl.

Adult↗

The diagnosis and management of hypertensive crises.

Severe hypertension is a common clinical problem in the United States, encountered in various clinical settings. Although various terms have been applied to severe hypertension, such as hypertensive crises, emergencies, or urgencies, they are all characterized by acute elevations in BP that may be associated with end-organ damage (hypertensive crisis). The immediate reduction of BP is only required in patients with acute end-organ damage. Hypertension associated with cerebral infarction or intracerebral hemorrhage only rarely requires treatment. While nitroprusside is commonly used to treat severe hypertension, it is an extremely toxic drug that should only be used in rare circumstances. Furthermore, the short-acting calcium channel blocker nifedipine is associated with significant morbidity and should be avoided. Today, a wide range of pharmacologic alternatives are available to the practitioner to control severe hypertension. This article reviews some of the current concepts and common misconceptions in the management of patients with acutely elevated BP.

Aortic Dissection↗

Automatic external defibrillators: lessons from the past, present and future.

Coronary artery disease remains the leading cause of death in the United States and most developed countries. Many of the victims die from sudden cardiac arrests, resulting from dysrhythmias-most commonly ventricular fibrillation. Since most cardiac arrests occur outside the hospital, implementing emergency services in the field will have a great impact on survival. With the development of the modern automatic external defibrillator (AED), early recognition and correction of these dysrhythmias by lay rescuers can significantly improve outcome from sudden death. This paper reviews the past, present and future development and applications of AEDs.

Electric Countershock↗

Physicians' own preferences to the limitation and withdrawal of life-sustaining therapy.

While limiting and forgoing therapy at the end of life is now accepted on medical, ethical, moral and legal grounds, many Americans continue to die with heroic measures being taken to prevent their death. Recent studies have demonstrated that physicians frequently attend to their patients without knowledge of their preferences with regards to end-of-life issues. It is postulated that a physician's personal preferences with regard to the limitation and withdrawal of life support and active euthanasia would effect the discussion they had with their patients. The purpose of this study was to analyze end-of-life preferences of a diverse group of practicing physicians. The participants were active attending physicians at a community hospital, a rural referral center, a large tertiary care referral academic complex, and a specialized tertiary care referral center all within the United States. A questionnaire was developed which was mailed to attending physicians at the four participating medical centers. The respondents provided basic demographic data, do-not-resuscitate (DNR) preferences under various clinical circumstances as well as responses to a number of case vignettes. Six hundred and forty physicians responded to the survey. The mean age of the respondents was 46 years; 72% were male. In the event of a cardiac arrest less than 20% of respondents would want to undergo cardiopulmonary resuscitation in the setting of chronic end stage organ failure; the positive response rate was 5% for metastatic cancer and 2% for Alzheimer's disease. If death was imminent, 87% of physicians indicated they would want treatment withdrawn. Similarly, 95% of respondents indicated that they would want treatment withdrawn should they be in a persistent vegetative state. Only 1% of respondents believed that health care providers should never remove or withhold life-sustaining therapy. Should they have advanced motor neuron disease, 38% of physicians indicated they would request that their life be ended. The majority of physicians surveyed volunteered that they would want life-sustaining measures to be limited at the end of their life. A significant number were in favor of active euthanasia. This study suggests that it is unlikely that physicians' personal beliefs in regards to end-of-life care result in the failure to discuss these issues with their patients.

Attitude of Health Personnel↗

Critical care and the World Wide Web.

The Internet was created in 1969, when the Advanced Research Projects Agency of the United States Department of Defense fired up an experimental network consisting of only four computers. Over the past five years there has been an exponential explosion in the number of computers added to this network. It is estimated that Internet traffic doubles every 100 days with more than 100 million people worldwide now on-line. The Internet is so vast that practically every aspect of human interest is represented is some form or fashion. From recreation to applied science and technology, and from Critical Care Medicine case scenarios to digitized radiology images and pathology specimens, the Internet has become increasingly useful for critical care practitioners. To date, no resource is better equipped to assist critical care providers in many of their daily tasks. This article presents some of the historical developments of the Internet as well as common applications that are useful for critical care practitioners.

Critical Care↗

Severity scoring and outcome assessment. Computerized predictive models and scoring systems.

Severity of illness scoring systems and standardized death ratios are being used with increasing frequency as markers of quality of care and to compare and contrast the performance of ICUs. However, numerous factors unrelated to the quality of care delivered may impact the severity of illness score and standardized death ratios. This article reviews the commonly used severity scoring systems and factors that affect their predictive performance.

Computer Simulation↗

The ex vivo antimicrobial activity and colonization rate of two antimicrobial-bonded central venous catheters.

OBJECTIVE: Catheter-related sepsis is an important complication associated with the use of central venous catheters. Recent studies have suggested that antimicrobial-bonded catheters may reduce catheter colonization and catheter-related sepsis. The aim of this study was to determine the relationship between the antimicrobial activity and the colonization rate of two commercially available antimicrobial-bonded central venous catheters. DESIGN: Prospective, randomized, controlled, nonblinded study. SETTING: Medical intensive care unit of a university-affiliated teaching hospital. PATIENTS: One hundred twenty consecutive medical intensive care unit patients requiring new central venous catheters (fresh stick). INTERVENTIONS: Patients were randomized to receive a) a Standard Arrow; b) an ARROWgard; or c) a Cook Bio-Guard Spectrum central venous catheter. Central venous catheters were removed when they were no longer required or when catheter-related sepsis was suspected. Under aseptic conditions, the distal 12 cm of the removed catheters were cut into six 2-cm segments. Semiquantitative culture was performed (by roll technique) on the distal segment. Colonization was defined as >15 colony-forming units. Using a modified Kirby-Bauer technique, the zone of inhibition of the remaining five segments was determined against the following organisms: methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Enterococcus faecalis, Acinetobacter baumannii, and Candida albicans Catheters that were removed within 24 hrs of insertion were excluded from the analysis. MEASUREMENTS AND MAIN RESULTS: Seven patients were not assessable. The baseline clinical and demographic characteristics were similar among the three groups of patients. Eleven Standard Arrow (28%), seven ARROWgard (19%), and four Bio-Guard (11%) catheters were colonized (p = .05 for Bio-Guard vs. control). Staphylococci were the most common colonizing organisms. Two patients with Standard Arrow catheters (5%) and one patient with an ARROWgard catheter (3%) developed catheter-related sepsis. Antibiotic-coated catheters significantly inhibited the growth of all test organisms except C. albicans (p < or = .05). Zones of inhibition were significantly larger for the Bio-Guard compared with the ARROWgard catheter when tested against MRSA, S. epidermidis, and E. faecalis (p < or = .002). CONCLUSION: The Bio-Guard central venous catheter had greater ex vivo antimicrobial activity against MRSA, S. epidermidis, and E. faecalis compared with the ARROWgard catheter, and this was associated with a significantly lower rate of catheter colonization.

APACHE↗

The effect of acidified enteral feeds on gastric colonization in critically ill patients: results of a multicenter randomized trial. Canadian Critical Care Trials Group.

OBJECTIVE: To evaluate the effect of acidified enteral feeds on gastric colonization in critically ill patients compared with a standard feeding formula. DESIGN: Randomized, double-blind, multicenter trial. SETTING: Eight mixed intensive care units at tertiary care hospitals. PATIENTS: We recruited mechanically ventilated critically ill patients expected to remain ventilated for >48 hrs. We excluded patients with gastrointestinal bleeding, acidemia, and renal failure requiring dialysis. We enrolled 120 patients; 38% were female, age (mean +/- SD) was 57.6+/-19.3 yrs, and Acute Physiology and Chronic Health Evaluation II score (mean +/- SD) was 21.6+/-7.6. INTERVENTIONS: Vital High Nitrogen (Abbott Laboratories, Ross Products Division, Columbus, OH) was used as the standard feeding formula for the control group (pH = 6.5). Hydrochloric acid was added to Vital High Nitrogen to achieve a pH of 3.5 in the experimental group. MEASUREMENTS AND MAIN RESULTS: The main outcome measure was gastric colonization. Secondary outcomes included gastric pH, pneumonia, and mortality. The mean gastric pH in patients receiving acid feeds was lower (pH = 3.3) compared with controls (pH = 4.6; p<.05). One patient (2%) on acid feeds was colonized in the stomach with pathogenic bacteria, compared with 20 patients (43%) in the control group (p<.001). There was no difference in the incidence of pneumonia (6.1% in the acid feeds group vs. 15% in the control group; p = .19). Overall, there were 15 deaths in the acid feeds group and seven in the control group (p = .10); four patients in the acid feeds group and three in the control group died during the study period (p not significant). CONCLUSIONS: Acidified enteral feeds preserve gastric acidity and substantially reduce gastric colonization in critically ill patients. Larger studies are needed to examine its effect on ventilator-associated pneumonia and mortality.

Bacteria↗