Biomedical subjects
Publications and source records attributed to Joseph Varon.
A 30-year-old woman had bilateral anterior ischemic optic neuropathy after undergoing large-volume liposuction. Visual function remained stable over a four-month follow-up, with decreased visual acuity and marked constriction of the visual fields. To our knowledge, this is the second reported case of ischemic optic neuropathy in this setting.
Status epilepticus is a major medical emergency associated with significant morbidity and mortality. Status epilepticus is best defined as a continuous, generalized, convulsive seizure lasting > 5 min, or two or more seizures during which the patient does not return to baseline consciousness. Lorazepam in a dose of 0.1 mg/kg is the drug of first choice for terminating status epilepticus. Patients who continue to have clinical or EEG evidence of seizure activity after treatment with lorazepam should be considered to have refractory status epileptics and should be treated with a continuous infusion of propofol or midazolam. This article reviews current information regarding the management of status epilepticus in adults.
BACKGROUND: In critically ill patients who are receiving mechanical ventilation, the factors associated with physicians' decisions to withdraw ventilation in anticipation of death are unclear. The objective of this study was to examine the clinical determinants that were associated with the withdrawal of mechanical ventilation. METHODS: We studied adults who were receiving mechanical ventilation in 15 intensive care units, recording base-line physiological characteristics, daily Multiple Organ Dysfunction Scores, the patient's decision-making ability, the type of life support administered, the use of do-not-resuscitate orders, the physician's prediction of the patient's status, and the physician's perceptions of the patient's preferences about the use of life support. We examined the relation between these factors and withdrawal of mechanical ventilation, using Cox proportional-hazards regression analysis. RESULTS: Of 851 patients who were receiving mechanical ventilation, 539 (63.3 percent) were successfully weaned, 146 (17.2 percent) died while receiving mechanical ventilation, and 166 (19.5 percent) had mechanical ventilation withdrawn. The need for inotropes or vasopressors was associated with withdrawal of the ventilator (hazard ratio, 1.78; 95 percent confidence interval, 1.20 to 2.66; P=0.004), as were the physician's prediction that the patient's likelihood of survival in the intensive care unit was less than 10 percent (hazard ratio, 3.49; 95 percent confidence interval, 1.39 to 8.79; P=0.002), the physician's prediction that future cognitive function would be severely impaired (hazard ratio, 2.51; 95 percent confidence interval, 1.28 to 4.94; P=0.04), and the physician's perception that the patient did not want life support used (hazard ratio, 4.19; 95 percent confidence interval, 2.57 to 6.81; P<0.001). CONCLUSIONS: Rather than age or the severity of the illness and organ dysfunction, the strongest determinants of the withdrawal of ventilation in critically ill patients were the physician's perception that the patient preferred not to use life support, the physician's predictions of a low likelihood of survival in the intensive care unit and a high likelihood of poor cognitive function, and the use of inotropes or vasopressors.
Hypertension is an extremely common clinical problem, affecting approximately 50 million people in the USA and approximately 1 billion individuals worldwide. Approximately 1% of these patients will develop acute elevations in blood pressure at some point in their lifetime. A number of terms have been applied to severe hypertension, including hypertensive crises, emergencies, and urgencies. By definition, acute elevations in blood pressure that are associated with end-organ damage are called hypertensive crises. Immediate reduction in blood pressure is required only in patients with acute end-organ damage. This article reviews current concepts, and common misconceptions and pitfalls in the diagnosis and management of patients with acutely elevated blood pressure.
BACKGROUND: Perceptions about functional and employment status before admission to the intensive care unit (ICU) may influence how patients and clinicians make decisions about cardiopulmonary resuscitation. OBJECTIVE: To examine the relationship between cardiopulmonary resuscitation directives established within 24 hours of admission to the ICU and clinical perceptions of premorbid functional and employment status. DESIGN: Prospective observational study in 15 university-affiliated centers in Canada, the United States, Australia, and Sweden. PATIENTS: A total of 1,008 ICU patients aged 18 years or older expected to stay in the ICU at least 72 hours. MEASUREMENTS: By using multinomial logistic regression, we examined the relationship between functional status and employment status perceived by the ICU team 1 month before ICU admission (the independent variables) and resuscitation status (the dependent variable). Each patient had either an explicit resuscitation directive (to resuscitate or not to resuscitate), or an implicit resuscitation directive to resuscitate. RESULTS: On average, patients were 61.7 years (+/-17.4 y) old with an Acute Physiology and Chronic Health Evaluation (APACHE) II score of 21.5 (+/-8.7); 846 (83.9%) were ventilated mechanically within 48 hours and 345 (34.2%) died in the ICU. Most patients (793, 78.7%) had no explicit resuscitation directive; 98 (9.7%) had an explicit plan to resuscitate, whereas 117 (11.6%) had an explicit plan of do-not-resuscitate. Of 1,008 patients, 98 (9.7%) were severely functionally limited, 217 (21.5%) were somewhat limited, 628 (62.3%) were totally independent, and 65 (6.4%) had unknown functional status 1 month before ICU admission. Severe functional status impairment was associated moderately with an explicit plan to resuscitate (odds ratio, 2.2 relative to no explicit directive) and associated strongly with an explicit do-not-resuscitate plan (odds ratio, 6.2 relative to no explicit directive, P value on the difference =.011). This relationship was not influenced by age, sex, APACHE II score, medical or surgical status, admission diagnosis, employment status, or city. However, severe functional status was associated strongly and significantly with an explicit do-not-resuscitate directive among those who could not participate in decision making (odds ratio, 8.2; 95% confidence interval, 4.5-15.0), and more weakly associated in those who could participate (odds ratio, 1.7; 95% confidence interval, 0.3-8.6). Being unemployed was associated with an increased odds of an explicit resuscitation directive versus no explicit directive (odds ratio, 5.5; 95% confidence interval, 2.2-13.4). CONCLUSIONS: Functional status impairment perceived by the ICU team is associated clearly with do-not-resuscitate directives in patients unable to participate in decision making. However, the association appears much weaker in patients able to participate in decision making. PATIENTS' perceived employment status also may influence resuscitation decisions. Our results emphasize the challenges of ensuring that crucial resuscitation decisions are not affected adversely by patients' inability to participate in decisions, and by their functional and employment status.
Gatherings of large numbers of people at concerts, sporting events, and other occasions lead to an assembled population with a potential for a wide variety of illnesses and injuries. The collection of large numbers of people in a single location has led some authors to recommend the placement of resuscitation equipment or other medical services in close proximity to these activities. These recommendations not withstanding, data on the frequency of critical illness at mass gatherings (a group exceeding 1000 persons) are difficult to ascertain. Therefore, it was the purpose of this study to describe the incidence of critical illnesses among assembled populations at mass gatherings. An observational prospective study was conducted involving patient encounters at a large, multipurpose, indoor mass-gathering complex in Houston, Texas occurring between September 1, 1996 and June 30, 1997. Demographic, treatment, disposition and diagnostic data were analyzed in a computerized database. Of the 3.3 million attendants to the 253 events analyzed during the 10-month study period, there were 2762 (0.08%) patient encounters. Fifty-two percent were women. Mean age was 32 +/- 15.6 years. Of these patients, 51.1% were patrons and the remaining patients were employees or contractors of the facility. A wide variety of illness was seen with trauma (39.5%), headache (31%), and other medical complaints (29.5%) being most frequent. Disposition of the patients included 95.3% being discharged to go back to the event and 2.2% being counseled to seek other medical attention. One hundred twenty-nine patients (4.7%) were referred to the Emergency Department (ED); of these, 70 were transferred for abrasions, lacerations, or skeletal injuries and 13 for chest pain. Of those referred to the ED, 50 (38.7%) patients were transported by ambulance and only 17.4% were admitted to telemetry, with none admitted to an ICU. It is concluded that critical illness at mass gatherings is infrequent, as seen in this study, with very few being admitted to telemetry and none to an ICU. Careful consideration of cost-benefit should occur when determining allocation of resources for these activities.
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Self-Contained Underwater Breathing Apparatus (SCUBA) diving popularity is increasing tremendously, reaching a total of 9 million people in the US during 2001, and 50,000 in the UK in 1985. Over the past 10 years, new advances, equipment improvements, and improved diver education have made SCUBA diving safer and more enjoyable. Most diving injuries are related to the behaviour of the gases and pressure changes during descent and ascent. The four main pathologies in diving medicine include: barotrauma (sinus, otic, and pulmonary); decompression illness (DCI); pulmonary edema and pharmacological; and toxic effects of increased partial pressures of gases. The clinical manifestations of a diving injury may be seen during a dive or up to 24 h after it. Physicians living far away from diving places are not excluded from the possibility of encountering diver-injured patients and therefore need to be aware of these injuries. This article reviews some of the principles of diving and pathophysiology of diving injuries as well as the acute treatment, and further management of these patients.
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Sudden cardiac death is the leading cause of death in the US and most developed nations. Ventricular fibrillation (VF) is the most common initial rhythm in survivors of cardiac arrest. The most important factor in determining survival from VF is the time from collapse to administration of the first defibrillation shock. Automatic external defibrillators (AEDs) have been developed and widely deployed in an attempt to reduce the time to defibrillation. Data on early defibrillation using AEDs has led to a number of public access defibrillator placements in the US and ongoing studies of public access AED use. The safety of lay person AED use is clear. Clearly some concentrated captive populations (e.g. airports, airplanes) may benefit from public access AEDs. Therefore, widespread AED education as a means of increasing public acceptance of lay person AED use must be a priority. As technology evolves costs will decline, however, the current economic reality requires careful consideration of the cost effectiveness of specific AED placement.
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Asthma is a common cause of morbidity and mortality in the United States, with over two million Emergency Department (ED) visits each year. Airway inflammation is recognized as a major component in the pathophysiology of asthma. The classic presentation of asthma is that of wheezing, cough, and dyspnea, however, the severity of airflow limitation correlates poorly with clinical signs. Forced exhaled volume in 1 s (FEV(1)) and the peak expiratory flow rate (PEFR) are direct reflections of the severity of airflow obstruction and are the standard measures used in the ED to assess the severity of airflow obstruction and the response to therapy. Beta2-adrenergic bronchodilators, ipratropium bromide, and corticosteroids form the cornerstone of therapy. Inhaled corticosteroids, leukotriene modifying drugs, and noninvasive positive pressure ventilation should be considered in patients with severe disease and in those who have responded poorly to standard therapy. Mechanical ventilation is usually well tolerated and may be lifesaving in patients with refractory asthma. Precautions are required to prevent dynamic hyperinflation during assisted ventilation.
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