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Biomedical subjects

A B Sanders

Publications and source records attributed to A B Sanders.

At least 55 records · Page 3Linked to original sources
PubMed1993

Effects of graded doses of epinephrine on both noninvasive and invasive measures of myocardial perfusion and blood flow during cardiopulmonary resuscitation.

OBJECTIVES: Epinephrine administered during cardiopulmonary resuscitation (CPR) is known to increase aortic diastolic and myocardial perfusion pressures, while enhancing myocardial blood flow. Optimal dosing of epinephrine during CPR is less certain. Interest in high-dose epinephrine use under such circumstances is increasing. The effect of different doses of epinephrine on simultaneously measured perfusion pressures, myocardial blood flow, cardiac output, and end-tidal CO2 (PCO2) (used as an indirect measure of cardiac output during CPR) is unknown. DESIGN: Prospective, sequential evaluation of no epinephrine, standard dose epinephrine, and high-dose epinephrine. SETTING: An experimental resuscitation laboratory. SUBJECTS: Twelve domestic swine. INTERVENTIONS: Myocardial perfusion pressure, myocardial blood flow, cardiac output, and end-tidal PCO2 were studied after various doses of epinephrine were administered during prolonged CPR. After 3 mins of untreated ventricular fibrillation, each animal received 5 mins of CPR without epinephrine, 5 mins of CPR after standard dose epinephrine (0.02 mg/kg), and 5 mins of CPR after high-dose epinephrine (0.2 mg/kg). Cardiac output and regional myocardial blood flow values were measured with nonradioactive, colored microspheres. MEASUREMENTS AND MAIN RESULTS: Myocardial perfusion pressure (aortic diastolic minus right atrial diastolic) was significantly (p < .05) increased over baseline with high-dose epinephrine (35 +/- 8 vs. 14 +/- 4 mm Hg), but not with standard dose epinephrine (20 +/- 5 vs. 14 +/- 4 mm Hg). Epinephrine's effect on myocardial blood flow was similar, increasing after the high dose (71 +/- 21 vs. 20 +/- 5 mL/min/100 g; p > .05), but not with the standard dose (23 +/- 6 vs. 20 +/- 5 mL/min/100 g). Cardiac output decreased significantly (p < .05) after high-dose epinephrine (7 +/- 1 vs. 13 +/- 1 mL/min/kg). Mean end-tidal PCO2 levels were lower after high-dose epinephrine (15 +/- 2 vs. 20 +/- 2 mm Hg; p < .05) but not after standard dose epinephrine (19 +/- 2 vs. 20 +/- 2 mm Hg). CONCLUSIONS: Standard dose epinephrine had minimal effect on myocardial perfusion pressure, myocardial blood flow, cardiac output, or end-tidal PCO2. High-dose epinephrine enhanced myocardial perfusion pressure and myocardial blood flow despite significantly decreasing cardiac output.

Animals↗
PubMed1993

Bystander cardiopulmonary resuscitation. Is ventilation necessary?

BACKGROUND: Prompt initiation of bystander cardiopulmonary resuscitation (CPR) improves survival. Basic life support with mouth-to-mouth ventilation and chest compressions is intimidating, difficult to remember, and difficult to perform. Chest compressions alone can be easily taught, easily remembered, easily performed, adequately taught by dispatcher-delivered telephone instruction, and more readily accepted by the public. The principal objective of this study was to evaluate the need for ventilation during CPR in a clinically relevant swine model of prehospital witnessed cardiac arrest. METHODS AND RESULTS: Thirty seconds after ventricular fibrillation, swine were randomly assigned to 12 minutes of chest compressions plus mechanical ventilation (group A), chest compressions only (group B), or no CPR (group C). Standard advanced cardiac life support was then provided. Animals successfully resuscitated were supported for 2 hours in an intensive care setting, and then observed for 24 hours. All 16 swine in groups A and B were successfully resuscitated and neurologically normal at 24 hours, whereas only 2 of 8 group C animals survived for 24 hours (P < .001, Fisher's exact test). One of the 2 group C survivors was comatose and unresponsive. CONCLUSIONS: In this swine model of witnessed prehospital cardiac arrest, the survival and neurological outcome data establish that prompt initiation of chest compressions alone appears to be as effective as chest compressions plus ventilation and that both techniques of bystander CPR markedly improve outcome compared with no bystander CPR.

Animals↗
PubMed1992

Geriatric emergency medicine: a survey of practicing emergency physicians.

STUDY OBJECTIVES: To evaluate the current status of clinical, educational, social, ethical, and resource issues related to the care of the elderly among practitioners of emergency medicine. DESIGN: A mailed survey instrument. SETTING: None. TYPE OF PARTICIPANTS: Practicing emergency physicians randomly drawn from the membership list of the American College of Emergency Physicians. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 971 surveys were mailed, with 433 usable surveys among the 485 (50%) respondents. The surveyed emergency physicians anticipated a major impact on emergency department patient flow and bed availability in the hospital and ICU as the population ages. For each of seven clinical presentations (abdominal pain, altered mental status, chest pain, dizziness/vertigo, fever without a source, headache, multisystem trauma), 45% or more of the emergency physicians have more difficulty in the management of older compared with younger patients. Most respondents reported that each of these presentations required more time and resources for older patients. The majority believed research, the availability of continuing medical education, and time spent during residency training regarding geriatric emergency medicine was inadequate. CONCLUSION: Practicing emergency physicians are uncomfortable with elderly patients, and this may reflect the inadequacies of training, research, and continuing education in geriatric emergency medicine.

Aged↗
PubMed1992

Geriatric patient emergency visits. Part I: Comparison of visits by geriatric and younger patients.

OBJECTIVES: To describe emergency department use by the elderly, to define problems associated with emergency care of the elderly, and to compare these results with those for younger adult patients. DESIGN: Retrospective, controlled chart review. SETTING: Six geographically distinct US hospital EDs. PARTICIPANTS: From each site, a stratified sample (approximately 7:3) of elderly (65 years or older) and nonelderly (21 to 64 years old) control patients treated during the same time period was used. METHODS: Standardized review of ED records and billing charges. Comparisons of elderly and control patient groups using chi 2 analysis and Mann-Whitney U test (alpha = 0.05). RESULTS: Four hundred eighteen elderly patients and 175 nonelderly controls were entered into the study. The elderly were more likely to arrive by ambulance (35% versus 11%; P less than .00001). More elderly than controls presented with conditions of either high or intermediate urgency (78% versus 61%; P less than .0003). The elderly more frequently presented with comorbid diseases (94% versus 63%; P less than .00001). Other findings for the elderly included a longer mean stay in the ED (185 versus 155 minutes; P less than .003), higher laboratory (78% versus 53%; P less than .00001) and radiology (77% versus 52%; P less than .00001) test rates, higher mean overall care charges ($471 versus $344; P less than .00001), and an admission rate (47% versus 19%; P less than .00001) twice that of younger adults. CONCLUSION: Resource use and charges associated with emergency care are higher for the elderly than for younger patients. Increases in emergency resources and personnel or improvement in efficiency will be needed to maintain emergency care at present levels as the US population continues to grow and age.

Adult↗
PubMed1992

Geriatric patient emergency visits. Part II: Perceptions of visits by geriatric and younger patients.

OBJECTIVES: To compare group perceptions of reasons for emergency department care, ED use patterns, and the effect of illness on self-care ability for elderly and younger adult patients. DESIGN: Patient survey. SETTING: Six geographically distinct US hospital EDs. PARTICIPANTS: From each site, a stratified sample (approximately 7:3) of elderly (65 years and older) and nonelderly (21 to 64 years old) control ED patients treated during the same time period was contacted. METHODS: Three hundred ninety-nine elderly patients and 172 adult controls were interviewed using a structured survey instrument. Groups were compared using chi 2 analysis and the Mann-Whitney U test. RESULTS: Both the elderly and the control patients (49% versus 38%) commonly stated that the most important reason for coming to the ED was because they were "too sick to wait for an office visit." Of patients with a regular physician, both groups often were referred to the ED by their primary care provider (35% versus 26%). While the elderly had more visits to their primary care provider (3.3 versus 2.9 visits; P less than .00001), there was no difference in the number of ED visits (1.5 versus 1.6 visits) during the preceding six months. Of those released from the ED, more elderly noted deterioration in their ability to care for themselves as a result of their illness (21% versus 11%; P less than .03). CONCLUSION: The elderly use the ED for reasons similar to those for younger adults. Often they feel too ill to wait for an office visit or are referred in by their primary care provider. Elderly patients more commonly have difficulty with self care after release home, and emergency physicians must plan accordingly.

Adult↗
PubMed1992

Use of emergency departments by elderly patients: projections from a multicenter data base.

STUDY OBJECTIVES: To assess the use of emergency medical care by the elderly in the United States, including emergency department visits, level of ED care required, ambulance services, and hospital admission rate. SETTING AND PARTICIPANTS: A multicenter computerized data base of 70 hospitals in 25 states. DESIGN: A retrospective review of elderly patients seeking ED care and comparison of elderly and nonelderly patients. The data were then used to estimate the use of emergency medical services nationally. MEASUREMENTS AND MAIN RESULTS: Fifteen percent of the 1,193,743 ED visits were made by patients 65 years or older. Thirty-two percent of elderly patients seen in EDs were admitted to the hospital, compared with 7.5% of nonelderly patients. Seven percent of elderly patients were admitted to ICUs, compared with 1% of nonelderly patients. Thirty percent of elderly patients seeking emergency care used ambulance transports compared with 8% of nonelderly. It is estimated that 13,693,400 elderly patients were seen in EDs in 1990, with more than 4 million patients admitted to hospitals. Compared with the nonelderly, the elderly are 4.4 times more likely to use ambulance transport, 5.6 times more likely to be admitted to the hospital, 5.5 times more likely to be admitted to an intensive care bed, and 6.1 times more likely to be classified as a comprehensive ED level of service. In our sample, 36% of all patients arriving by ambulance to the ED, 43% of all ED admissions, and 48% of all intensive care admissions were geriatric patients. CONCLUSION: With the rapid growth of the size of the elderly population, it is important that we assess the emergency medical resources needed to care for the geriatric population.

Aged↗
PubMed1992

Geriatric training in emergency medicine residency programs.

STUDY OBJECTIVES: The health care needs of the elderly population are significantly different from those of younger patients and require special knowledge and skills on the part of emergency physicians. The purpose of this study was to identify the nature and extent of geriatric training currently provided to emergency medicine residents. DESIGN: Self-administered survey distributed to residency directors of the 85 accredited emergency medicine residency programs in the United States. INTERVENTIONS: The survey consisted of 17 questions focusing on residency directors' views about teaching and research of geriatric emergency care. RESULTS: Survey information was obtained from 85 (100%) emergency medicine residency programs. Forty percent (34 of 85) of respondents believed the teaching of geriatric emergency care was inadequate; 44 programs (52%) plan to increase the number of didactic hours devoted to geriatrics (mean increase of 5.9 hours). The five geriatric topics most frequently taught included acute dementia, atypical presentation of illness, common complaints in the elderly, geriatric trauma, and ethical issues. Sixty-five percent believed ongoing national research efforts regarding geriatric emergency medicine were insufficient; 21 programs (25%) had faculty involved in geriatric studies. Most respondents reported that growing numbers of elderly will have a major impact on all areas of patient care in the near future. CONCLUSION: Although geriatric emergency care is becoming an integral part of the emergency medicine residency program, there may be a need for better focused and more intensive training.

Aged↗
PubMed1992

Care of the elderly in emergency departments: conclusions and recommendations.

Little attention is being paid to the special needs of elderly persons in emergency departments. Emergency health care professionals feel less comfortable caring for elderly than for nonelderly patients. The social and personal concerns of the elderly frequently are not addressed in ED encounters. There is a paucity of research and education in geriatric emergency medicine. Overall principles of care for elderly patients seeking emergency care have not been defined as they have for other special populations such as children. The disease-oriented model used for caring for nonelderly adult patients in EDs may not be appropriate for elderly patients. The emergency care of the elderly requires significantly more health care resources than does that of the nonelderly. Compared with nonelderly patients, elderly patients seeking emergency care are four times more likely to use ambulance services, five times more likely to be admitted to the hospital, five times more likely to be admitted to an intensive care bed, and six times more likely to receive comprehensive emergency services. Although 12% of the population is 65 years or older, this group accounted for 36% of all ambulance patient transports to EDs, 43% of all hospital ED admissions, and 48% of all critical care admissions from EDs. These problems are particularly important at this time because many hospitals and their EDs are faced with significant problems of overcrowding and inadequate resources to meet the health care needs of the communities they serve. Although the elderly are the fastest-growing segment of the population, little or no planning is ongoing to meet the emergency health care needs of the elderly in the future. The task force has provided specific recommendations for addressing these problems.

Aged↗
PubMed1992

Factors influencing resident career choices in emergency medicine.

OBJECTIVE: To assess the attitudes of residents in emergency medicine regarding a career in academics. DESIGN: A 22-item questionnaire was administered to residents in conjunction with the yearly American Board of Emergency Medicine inservice examination. Demographic information and factors influencing career intent were elicited. Respondents were classified by intent on a career in emergency medicine. A three-way analysis of variance was used to address group differences for eight specific factors impacting on career decision. Chi-square analysis was used to address questions involving relationships among variables with dichotomous or categorical responses. RESULTS: The survey was distributed to 1,654 residents, and 1,238 (75%) completed the questionnaire. Motivating factors demonstrating significant differences between those residents planning an academic career and those not interested in academe were a desire to do research, desire to teach, desire to make a contribution to medicine, and exposure to role models, with less emphasis on the need for free time for other interests and less concern regarding practice location. More than 80% of those not going into academic emergency medicine believed they were adequately exposed to research in residency compared with 65% of those intent on a career in academe (P less than .01). Research in medical school, residency, and authorship of a research paper were significantly more prevalent for those residents desiring a career in academe (P less than .01). Twenty-six percent of residents responded that their role models for research were less than adequate. Seventeen percent of residents intend to take fellowship training. The most popular fields for fellowships were toxicology (25%), emergency medical services (21%), pediatrics (15%), and research (9%). CONCLUSION: The results of this survey address attitudes among residents toward a career in academic emergency medicine. Factors such as motivation, role models, and exposure to research may help academicians plan strategies to meet the future needs of academic emergency medicine.

Attitude of Health Personnel↗
PubMed1992

A study of chest compression rates during cardiopulmonary resuscitation in humans. The importance of rate-directed chest compressions.

A prospective, cross-over trial was performed comparing two different rates of precordial compression using end-tidal carbon dioxide as an indicator of the efficacy of cardiopulmonary resuscitation in 23 adult patients. A second purpose of this study was to determine the effect of audio-prompted, rate-directed chest compressions on the end-tidal carbon dioxide concentrations during cardiopulmonary resuscitation. Patients with cardiac arrest received external chest compressions, initially in the usual fashion without rate direction and then with rhythmic audiotones for rate direction at either 80 compressions per minute or 120 compressions per minute. Nineteen of 23 patients had higher end-tidal carbon dioxide levels at the compression rate of 120 per minute. The mean end-tidal carbon dioxide level during compressions of 120 per minute was 15.0 +/- 1.8 mm Hg, slightly but significantly higher than the mean level of 13.0 +/- 1.8 mm Hg at a compression rate of 80 per minute. However, end-tidal carbon dioxide levels increased rather dramatically when audiotones were used to guide the rate of chest compressions. Mean end-tidal carbon dioxide concentration was 8.7 +/- 1.2 mm Hg during standard cardiopulmonary resuscitation immediately before audio-prompted, rate-directed chest compression and increased to 14.0 +/- 1.3 mm Hg after the first 60 seconds of audible tones directing compressions. Using end-tidal carbon dioxide as an indicator of cardiopulmonary resuscitation efficacy, we conclude that audible rate guidance during chest compressions may improve cardiopulmonary resuscitation performance.

Aged↗
PubMed1991

The effect of malnutrition on vaccination against Dermatophilus congolensis infection in ruminants.

Vaccination against Dermatophilus congolensis was carried out in groups of lambs raised on optimal or energy deficient diets. The groups differed significantly in weight, body condition score and plasma total protein and albumin. All animals were then challenged with D. congolensis in a dose response infection model. The vaccine was effective in the well nourished animals, reducing the number of affected lambs in the vaccinated group and the severity of the lesions and increasing the minimum dose required to cause infection. In contrast, all of the vaccinated energy-deficient lambs developed lesions. There was some evidence of vaccine effect in these animals but this was not as marked as that seen in the well nourished lambs. The malnourished lambs, vaccinated and non-vaccinated, took longer to heal than the well nourished groups. Resistance to challenge was not associated with serum antibodies or skin test reactivity to D. congolensis antigens.

Actinomycetales↗
PubMed1991

Limitations of open-chest cardiac massage after prolonged, untreated cardiac arrest in dogs.

STUDY OBJECTIVES: Open-chest cardiac massage is an effective method of resuscitation if instituted within 15 minutes of normothermic cardiac arrest that has failed to respond to ongoing closed-chest CPR efforts. The usefulness of invasive forms of CPR after various periods of untreated cardiac arrest is less certain. This study was performed to determine the effectiveness of open-chest resuscitation after prolonged periods of untreated cardiac arrest. SETTING AND DESIGN: Prospective, controlled laboratory investigation using an animal model of cardiac arrest. Open-chest cardiac massage initially was compared to standard closed-chest compression CPR. The efficacy of open-chest CPR then was evaluated after ten and 40 minutes of untreated ventricular fibrillation. TYPE OF PARTICIPANTS: Twenty mongrel dogs (24 +/- 1 kg). MEASUREMENTS AND MAIN RESULTS: After 20 minutes of untreated ventricular fibrillation, open-chest resuscitation was significantly better than closed-chest efforts for the production of coronary perfusion pressure (58 +/- 14 vs 2 +/- 1 mm Hg; P less than .05) and initial resuscitation success (five of five vs one of five; P less than .03). Open-chest cardiac massage was equally effective for initial resuscitation if begun after ten or 20 minutes of untreated ventricular fibrillation (five of five vs five of five), but if untreated ventricular fibrillation continued for 40 minutes prior to instituting open-chest massage, no resuscitation benefit was found (none of five; P less than .005). There were marked differences in 24-hour survival depending on the length of time untreated cardiac arrest continued prior to instituting open-chest resuscitation efforts. After 20 minutes of ventricular fibrillation, initial resuscitation was successful with open-chest massage, but long-term survival was poor. CONCLUSION: Open-chest cardiac massage did not produce long-term survival if untreated cardiac arrest persisted for 20 or more minutes prior to invasive resuscitation efforts.

Animals↗
PubMed1991

Ultrasound for the detection of foreign bodies.

STUDY OBJECTIVE: To determine the ability of an emergency physician to detect a variety of foreign bodies in an experimental model using a portable ultrasound device. DESIGN: Ten pieces of beef were sliced into cubes approximately 6 cm on each side. Six different groups of foreign bodies were examined: gravel, cactus spine, glass, metal, wood, and plastic. An independent observer placed the objects in a random fashion into the beef cubes. One hundred twenty observations were made using sets of ten beef cubes at a time. Five foreign bodies were placed into each set of ten beef cubes. INTERVENTIONS: A blinded emergency physician used a portable ultrasound with a 7.5-MHz transducer to determine the presence or absence of a foreign body in each cube. MEASUREMENTS AND MAIN RESULTS: Ultrasound detected 59 of 60 foreign bodies, including all cubes of meat embedded with gravel, cactus spine, plastic, metal, and wood. Glass was detected nine of ten times. Of the 60 cubes of meat with no foreign bodies, one false-positive was recorded. This yielded sensitivity, specificity, positive predictive value, and negative predictive value of 98%. Positive determinations by ultrasound were significantly greater in the meat cubes with foreign bodies compared with the control group with no foreign bodies (P less than .001 by chi 2). Although the subset of glass foreign bodies had one false-positive and one false-negative, it was not significantly different in comparison with the other groups (P greater than .05 by chi 2). CONCLUSION: Ultrasound has promise as a diagnostic tool for the detection of a variety of foreign bodies. Further clinical studies using ultrasound for the detection of foreign bodies are warranted.

Emergencies↗
PubMed1991

The effect of bicarbonate on resuscitation from cardiac arrest.

STUDY OBJECTIVES: This study attempted to determine the effect of bicarbonate administration on resuscitation in a porcine model of prolonged cardiac arrest. DESIGN: After instrumentation, 26 swine were subjected to ventricular fibrillation for 15 minutes (16 animals) or 20 minutes (ten animals) with no resuscitative efforts. INTERVENTIONS: Resuscitation attempts with open-chest cardiac massage and epinephrine were used in all animals after the arrest period. The experimental group was given sodium bicarbonate (3 mEq/kg), and the control group received 3% saline (5 mL/kg) at the initiation of cardiac massage. MEASUREMENTS: Resuscitation success, hemodynamics, and arterial and mixed venous gases were compared in the bicarbonate and hypertonic saline-treated groups. RESULTS: There was no difference in resuscitation rates between bicarbonate and nonbicarbonate-treated swine. After 15 minutes of ventricular fibrillation, six of eight bicarbonate-treated swine were resuscitated successfully compared with five of eight hypertonic saline-treated animals. None of the five bicarbonate-treated or five hypertonic saline-treated swine that underwent 20 minutes of ventricular fibrillation were resuscitated. The arterial and mixed venous pH values were significantly different in the bicarbonate-treated animals from values in the control group. There was no difference in systolic or diastolic blood pressures or myocardial perfusion pressure between the bicarbonate and hypertonic saline-treated animals. CONCLUSION: Despite correlation of arterial and venous acidemia, the use of sodium bicarbonate did not improve resuscitation from prolonged cardiac arrest.

Animals↗