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Biomedical subjects

C Aprahamian

Publications and source records attributed to C Aprahamian.

At least 37 records · Page 2Linked to original sources

Comparison of three methods of rewarming from hypothermia: advantages of extracorporeal blood warming.

We developed a new technique, extracorporeal venovenous rewarming (EVR), to rewarm hypothermic patients in the intensive care unit or operating room. We compared this method with the active external (standard) techniques of warming blankets; heated ventilator circuits, intravenous fluids, and gastric and peritoneal lavage; and cardiopulmonary bypass. The EVR technique warmed patients' blood or additional blood products and crystalloids to 40 degrees C at 150-400 mL/min and allowed survival from a core temperature of 31.1 degrees C after massive injury. The EVR technique rewarming patients more rapidly than standard techniques and may be most appropriate in patients with multisystem trauma when rapid correction of hypothermia-related hypovolemia, coagulopathy, and arrhythmia is necessary. Cardiopulmonary bypass is required in severely hypothermic patients with cardiac arrest. Standard techniques can be used when these immediately life-threatening conditions are not present.

Adult↗

Pediatric Trauma Score. Predictor of hospital resource use?

The Pediatric Trauma Score has been recommended to triage children with scores of 8 or less to a level 1 pediatric trauma center. The Injury Severity Score correlates well with the Pediatric Trauma Score. During a 36-month period ending December 31, 1985, paramedics saw 983 pediatric trauma patients (aged 17 years and younger) and intervened with advanced life support procedures in 196 (20%). One hundred forty-four patients receiving advanced life support were transported to either a level 1 adult trauma center or a pediatric community hospital. Our data confirm the correlation between Pediatric Trauma Score and Injury Severity Score and support recommendations to transport patients with Pediatric Trauma Scores of 8 or less to trauma facilities. We also conclude that Pediatric Trauma Scores may be useful in predicting hospital resource use.

Adolescent↗

Pseudomembranous colitis: how useful is endoscopy?

Clostridium difficile colitis may be diagnosed either by endoscopy or by laboratory tests. To determine the role of endoscopy, we reviewed 59 cases of confirmed C. difficile colitis. In all patients, the etiology was confirmed by stool tests. Twenty-nine underwent lower gastrointestinal endoscopy. In 16 (55%) there was endoscopic confirmation of pseudomembranes while 4 (14%) had only nonspecific colitis. There was no apparent difference in the rate of detection of pseudomembranes between rigid sigmoidoscopy (57%), flexible sigmoidoscopy (50%), and colonoscopy (50%). Vancomycin and metronidazole were equally effective therapy but treatment with vancomycin cost more than 250 times that for metronidazole. There were no patients in whom the diagnosis was made by endoscopy alone. Endoscopy was costly and insensitive, while noninvasive stool tests were cheap and accurate. We conclude that endoscopy should be relegated to a secondary role in the workup of antibiotic-associated diarrhea.

Colonoscopy↗

Temporary abdominal closure (TAC) for planned relaparotomy (etappenlavage) in trauma.

Planned relaparotomy (temporary abdominal closure) was studied prospectively in 20 trauma patients. Four died in the first 24 hours from hypothermia, coagulopathy, shock (three), and septic shock (one). The 16 survivors had a Velcro-like prosthetic placed to facilitate abdominal closure and re-entry. Prosthetic was necessary in eight because bowel edema precluded fascial closure, and useful for removal of packing (three) and for the management of peritonitis (five). The prosthetic did not open spontaneously, nor was it associated with evisceration or bowel fistula. Temporary abdominal closure (TAC) permitted reappraisal and staged repair of intra-abdominal pathology, including bowel resection and anastomosis. TAC identified 14 problems early: bleeding (five), bile leaks (two), GI complications (six), liver necrosis (one). Five patients developed superficial wound infections, and three went on to develop fascial necrosis.

Abdominal Injuries↗

Changes in splenic size after abdominal trauma.

After blunt abdominal trauma, the spleen often increases in volume on serial computed tomographic (CT) scans. To determine the frequency and significance of such enlargement, the authors performed a retrospective analysis of 44 hemodynamically stable patients who had experienced recent blunt abdominal trauma. The severity of splenic, hepatic, or other visceral injuries seen on each CT scan was numerically scored, and the amount of intraperitoneal fluid was assessed. Twenty-five patients (57%) had over 10% enlargement (average enlargement, 56%) on follow-up scans. Increasing volume did not correlate with clinical deterioration or the need for splenectomy. It did correlate modestly with the amount of blood in the peritoneum on CT scans, the number of units of blood transfused, and two clinical indexes of systemic trauma. Therefore, an enlarging spleen is not a CT indicator of a deteriorating clinical condition. This phenomenon is most likely due to marked adrenergic stimulation after injury and changing fluid volumes.

Abdominal Injuries↗

Electrocardiographic characteristics in EMD.

Little has been written concerning the initial electrocardiographic (EKG) characteristics and/or changes which occur as the result of treatment in the electromechanical dissociation (EMD) patient. The purpose of this retrospective study was to determine predictive indicators of successful resuscitation in EMD by evaluating various EKG parameters. During 72 months, ending December 31st, 1985, there were 503 non-poisoned, prehospital adult cardiac arrest patients whose initial rhythm was EMD. All patients had their initial prehospital EKG rhythm strip evaluated for rhythm type, rate, the presence of P waves, QT interval and QRS interval. In successfully resuscitated patients, the prehospital initial rhythm analysis and the rhythm analysis on emergency department presentation were compared. Successfully resuscitated patients presenting with EMD had significantly faster initial rates, higher incidences of P waves and average QRS and QT intervals shorter than patients not responding to therapy. Furthermore, successfully resuscitated patients had significantly increased heart rates, developed new onset of P waves, and shortened QT intervals in response to treatment. Successfully resuscitated and save patients had average initial and final QRS complex lengths within normal limits. Organized atrial activity on the initial EKG was also correlated with successful resuscitation. No patient with an initial EKG rhythm of second or third degree AV block survived to hospital discharge. No patient who presented to the emergency department with atrial fibrillation survived to hospital discharge. Similarly, supraventricular tachycaydia following resuscitative efforts appeared to be associated with a negative outcome. Rate normalization following treatment was correlated with save rate. Wide complex rhythms without atrial activity were most highly associated with unsuccessful resuscitation. We believe these observed electrocardiographic characteristics and/or changes in response to treatment may have predictive value in evaluating patients with EMD.

Arrhythmias, Cardiac↗

EMT-defibrillation: the Wisconsin experience.

The survival rate for patients with prehospital cardiac arrest has improved in some communities with early defibrillation by emergency medical technician-defibrillators (EMT-Ds). In rural areas, previous studies on survival with defibrillation by EMT-Ds have been variable. We conducted an EMT-D study to determine effectiveness in various prehospital settings. Sixty-four ambulance services from communities ranging in size from rural areas to city suburbs participated in our prospective study. EMTs were trained in rhythm recognition and the use of a manual defibrillator during a standardized 20-hour course. Over 18 months, data were collected locally for central analysis. Five hundred sixty-six patients with primary cardiac arrest were included in our study: 36 (6.4%) survived. Retrospective review revealed survival before EMT-D implementation to be 3.6% (P less than .02). Three hundred four patients (54%) had an initial rhythm of ventricular fibrillation, with 33 (11%) surviving. The survival rate for EMT-D-witnessed arrest with an initial rhythm of ventricular fibrillation was 42%. Patients with asystole were countershocked in our study; however, there were no survivors from this group. The neurologic status of survivors at time of hospital discharge was normal in 72%. The average response time, defined as time of emergency medical services activation to the time of EMT-D arrival, was 7.3 +/- 5.8 and 3.7 +/- 2.0 minutes for nonsurvivors and survivors, respectively (P less than .002). There were no survivors when the response time was more than eight minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Randomized study of epinephrine versus methoxamine in prehospital ventricular fibrillation.

Experimental data suggest that a pure alpha-agonist, such as methoxamine, may improve the outcome of patients in ventricular fibrillation. A double-blind, randomized, prospective study was conducted in a paramedic system comparing the use of methoxamine with epinephrine in enhancing conversion of ventricular fibrillation while otherwise following American Heart Association protocols. One hundred two patients in ventricular fibrillation not responding to initial defibrillations with a pulsatile rhythm were randomized into one of two groups, each containing 51 patients. Equipressor doses of epinephrine (0.5 mg) and methoxamine (5 mg) were given intravenously and repeated according to American Heart Association guidelines. The mean age, sex ratio, and mean paramedic response times were comparable for the two groups. The mean time at scene until conversion was 22 +/- 10 minutes for methoxamine and 17 +/- 7 minutes for epinephrine (P = NS). The methoxamine group received 3.1 +/- 1.4 doses as compared with 2.8 +/- 1.3 doses for the epinephrine group (P = NS). Conversion rate, defined as the percentage of patients who developed a pulse during resuscitation, was 27.5% for the methoxamine group and 49.0% for the epinephrine group (P less than or equal to .03). Successful resuscitation, defined as the conveyance of a patient to an emergency department with a pulse and rhythm, was 17.7% for the methoxamine group and 39.2% for the epinephrine group (P less than or equal to .02). Save rate, defined as the percentage of patients discharged alive after hospitalization, was 7.8% for the methoxamine group and 19.6% for the epinephrine group (P less than or equal to .07).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗

MAST-associated compartment syndrome (MACS): a review.

Compartment syndromes occur following lower extremity injuries and have been associated with the use of pneumatic or "medical" antishock trousers (MAST). Review of 12 previously reported cases and 15 new cases suggests that lower extremity trauma and systemic hypotension are cofactors responsible for the development of compartment syndrome but MAST use also contributes to the process by prolonging muscle ischemia. Complications of lower limb compartment hypertension may be averted by early recognition and fasciotomy. Associated amputations and mortality are directly related to the severity of injury, or indirectly to delay in diagnosis and treatment of the compartment syndrome and its complications.

Abdominal Injuries↗

Status of trauma center designation.

1) In 1986 20 states are designating trauma centers. 2) ACS guidelines appear to be the accepted standard. 3) Almost all of the states providing designation retain the power of final designation but allow individual hospitals to initiate the process. 4) Designation is usually based on actual capability and frequently requires a site visit team in which surgeons and emergency medicine physicians play a prominent role. 5) Designation appears to be for a finite period of time but half of the states do not provide for de-designation. 6) A national mandate is necessary for timely and uniform implementation of trauma center designation.

General Surgery↗

Blunt tibial artery trauma: predicting the irretrievable extremity.

Patients suffering blunt leg trauma resulting in below-knee fracture, tibial artery injury, and soft-tissue damage are at major risk for amputation. In an attempt to identify the factors which may forecast limb loss despite vascular surgical repair, all patients with tibial fractures admitted between 1980-1988 were reviewed. Forty-four of 366 (12%) patients presented with clinical evidence of tibial artery injury. Twenty-seven of these 44 patients had angiographic evidence of at least one patent tibial vessel providing adequate distal flow. The remaining 17 patients required operative repair of injured tibial arteries because of persistent distal ischemia. The amputation rate was 35% (6/17--4 BKA, 2 AKA), three of these having patent vascular repairs at the time of the amputation. Operative indications for amputation were ischemic nonviable muscle in three patients, and severe soft-tissue wound infection in three. Patients who required amputation had a significantly greater incidence (Fisher's exact test) of three or more fascial compartments involved in muscular injury (p = 0.005), two or more injured tibial vessels (p = 0.01), failed vascular reconstruction (p = 0.03), a cadaveric foot at initial exam (p = 0.03), and severe muscle crush injury or muscle tissue loss (p = 0.03). No extremity was salvaged when more than two of these factors was present, and a failed vascular reconstruction led to limb amputation in all cases. These factors will predict an irretrievable extremity following blunt tibial artery trauma, allowing amputation before life-threatening wound sepsis develops.

Adolescent↗

Pneumoperitoneum as a complication of cardiopulmonary resuscitation.

A case of pneumoperitoneum following cardiopulmonary resuscitation (CPR) is reported and 11 cases in the literature are reviewed. Four patients had laparotomies failing to demonstrate any visceral perforation or evidence of peritonitis in spite of the massive pneumoperitoneum present. Operative intervention immediately after resuscitation is associated with potentially high morbidity and mortality. Several diagnostic tools are used, including peritoneal lavage and contrast media tests, to accurately diagnose perforated viscus. To avoid an unnecessary celiotomy a clinical treatment protocol has been developed for patients with pneumoperitoneum secondary to CPR. Such diagnostic tools as peritoneal lavage and water-soluble contrast medium test are reviewed and included in this protocol. A nonsurgical approach to patient management may be reasonable if certain criteria are met.

Aged↗

Limitations of prehospital predictors of acute myocardial infarction and unstable angina.

Studies have attempted to define predictive indicators of diagnosis and/or prognosis for acute myocardial infarction (AMI) in the emergency department and to identify the need for hospital admission in patients with chest pain. Because prehospital predictors have not been defined, dispatchers, paramedics, and base station physicians continue to triage based on patient history. We reviewed 401 patients presenting in one year to an urban paramedic system with chest pain, normal vital signs, and stable rhythms to identify predictors of AMI and unstable angina. Thirty-one percent (123) had a diagnosis of AMI, 26% (105) unstable angina, and 43% (173) "other" diagnoses. Two-hundred seventy-eight patients required nitroglycerin administration, 182 required IV morphine, 14 developed arrhythmias requiring lidocaine, and two suffered cardiac arrest in the field. Nine other patients had a cardiac arrest after arrival in the ED. When comparing AMI and unstable angina patients to the "others," 64% (132) versus 36% (74) had radiation of pain (P less than .003), 72% (95) versus 28% (37) had diaphoresis (P less than .0001). Neither difficulty breathing, nausea/vomiting, vital signs, initial rhythm, nor past history of myocardial infarction were helpful in discriminating AMI and unstable angina from others. Comparing AMI alone versus others, the presence of ST segment elevation on lead II was present in 15% (18) AMIs, 3% (3) unstable angina, and 8% (14) others (P = .005). Diaphoresis also was a predictor of diagnosis with 51% (63) of the AMIs and 25% (69) of others exhibiting this sign (P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Treatment of blunt hepatic injuries: role of CT.

Serial dynamic upper abdominal computed tomography (CT) studies were performed on 20 patients as part of the conservative treatment of blunt hepatic injuries (hematoma, laceration, or fracture). Fourteen of these patients had either major or minor associated hemoperitoneum. In 13 patients, hemoperitoneum was either significantly reduced or absent by 1 week. A severe delayed hemorrhage occurred in one patient 7 1/2 days after admission; a large and unchanged volume of intraperitoneal fluid had been seen on a preceding abdominal CT scan. One other patient who had a satisfactory response underwent surgery for a pancreatic laceration. Serial abdominal CT studies are an integral part of the conservative treatment of blunt hepatic injuries and seem to be useful in monitoring resorption of hemoperitoneum and the pattern of healing of intrahepatic hematomas, lacerations, and fractures.

Hemoperitoneum↗

Decision making in prehospital sudden cardiac arrest.

Many studies of prehospital resuscitation report on selected populations. We examined a series of 445 unselected nontraumatic cardiac arrests. Emergency cardiac care (ECC) was not initiated in 126 (28%). ECC was begun in 319 (78%), but was terminated in 132 (33%). Ninety-four (21%) were admitted to the hospital with palpable pulses and organized rhythm (successful resuscitation/save rate for patients presenting in ventricular fibrillation was 50%/25%. Multivariate regression analysis was used to identify the relative importance of significant variables in predicting survival, and the analysis identified the presence of ventricular fibrillation, short paramedic response times, and short paramedic treatment times.

Aged↗

Bystander/first responder CPR: ten years experience in a paramedic system.

The effectiveness of bystander CPR recently has been challenged. We undertook a ten-year retrospective review of our prehospital experience with witnessed cardiorespiratory arrest to ascertain save rates in patients receiving and not receiving CPR before paramedic advanced life support (ALS). Traumatic and poisoning arrests and children less than 18 years old were excluded. A total of 1,905 patients presenting to a paramedic system from November 1, 1973, to October 31, 1983, were bystander-witnessed arrests and attempted paramedic resuscitations. Four hundred five paramedic-witnessed arrests were excluded. One hundred eighty-two of 1,248 (14.6%) who had CPR initiated before paramedic ALS arrival were saves, compared to 38 of 252 (15%) who had no CPR initiated until paramedic arrival (P = NS). A save was defined as a patient discharged from the hospital. The respective save rates for coarse ventricular fibrillation were 148 of 628 (23.6%) (CPR before paramedic arrival) vs 35 of 151 (CPR delayed until paramedic arrival) (23.2%); electromechanical dissociation (EMD), 11 of 209 (5.3%) vs 0 of 38; asystole, 19 of 401 (4.7%) vs 3 of 61 (4.9%); and ventricular tachycardia, four of ten (40%) vs 0 of two. In this prehospital system, bystander/first responder CPR was found not to improve hospital discharge rates except in patients with initially documented rhythm of EMD.

Adult↗

Rib radiographs for trauma: useful or wasteful?

In trauma to the chest, the clinical impression and the physical findings of rib fractures are nonspecific. Fractures often are not seen on initial films. The principal diagnostic goal should be the detection of significant complications (pneumothorax, hemothorax, major vascular injury, or pulmonary contusion) requiring admission. The therapeutic effort should be to provide pain relief and prevent the delayed development of atelectasis or pneumonia in patients with painful chest wall injuries, whether or not a fracture is detected initially. An upright posteroanterior chest radiograph has the greatest yield in detecting fractures and complications resulting from them. Tomograms and expiratory, oblique, and "coned-down" views should not be done routinely. The use of these more specific examinations may be indicated, however, in such cases as trauma to ribs 1 to 3 or 9 to 12. Their selective use in isolated cases (trauma to ribs 1 to 3 or 9 to 12) and suspected child abuse may indicate the need for these more specific examinations. Because detection of pulmonary complications of chest trauma is most important, a delayed or repeat upright posteroanterior chest radiograph may be the most cost-effective second radiograph. Significant medical care cost savings may be appreciated by limiting the use of specific rib views to instances in which it might influence the patient's therapy.

Adolescent↗