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Biomedical subjects

C Aprahamian

Publications and source records attributed to C Aprahamian.

At least 55 records · Page 3Linked to original sources

Prophylactic lidocaine in the prehospital patient with chest pain of suspected cardiac origin.

The prophylactic use of lidocaine in the patient with cardiac chest pain has been reported to reduce the incidence of sudden death from ventricular dysrhythmias in the hospital setting, but few studies have been done in the early prehospital phase. We conducted a randomized, prospective study comparing the effects of lidocaine versus no lidocaine in stable patients presenting with chest pain to a paramedic system. In a one-year period, 446 patients qualified for the study; 222 received lidocaine and 224 did not. The overall hospital mortality of the two groups was 8.1% and 6.7%, respectively (P = .35). Four patients in each group developed sudden death in the prehospital and emergency department settings with ventricular dysrhythmia as the precipitating rhythm. One hundred twenty-nine (29%) had an acute myocardial infarction. The lidocaine and control group contained 68 and 61 of the patients, respectively, with an overall mortality rate of 14.7% and 13.1% (P = .45). The development of significant dysrhythmias (frequent premature ventricular contractions, ventricular tachycardia, bradycardia, second- and third-degree heart blocks) after initiation into the study was similar in both groups of patients. The use of lidocaine was a factor in decreasing systolic blood pressure (P less than 0.03) but did not appear to be clinically significant. For stable patients presenting with chest pain of suspected cardiac origin, prophylactic lidocaine in the prehospital setting was not effective in preventing life-threatening dysrhythmias, but clinically significant side effects were not noted either.

Adult↗

Trauma center verification.

Sanctioned trauma center designation began in the late 1970's to improve hospital capabilities to care for injured patients. Guided by criteria established by the American College of Surgeons Committee on Trauma and led by surgeons dedicated to improving trauma care, many states focused early on the quality of care issue only to later struggle with the political consequences that followed the designation process. Institutional commitment to trauma care was often stated but seldom measured. Unlike the designation process with its strong emphasis on capabilities assessment, the verification process focused on performance documentation. Confirmation was sought in response time of key personnel, completeness of registry database, and trauma death audits. Trauma Committee minutes were reviewed and prehospital personnel interviewed to confirm institutional involvement in paramedic education and overall EMS system design. Other areas of documentation included trauma education at all levels, research, nursing audits, and outreach programs. We conclude that trauma center designation and verification are both essential and complementary. Effective trauma system performance requires trauma center designation plus a verification process to confirm institutional commitment of these resources for optimal care of the injured patient.

Accreditation↗

Calcium: limited indications, some danger.

Calcium chloride has been advocated since the 1920s for the resuscitation of asystole, electromechanical dissociation (EMD), and ventricular fibrillation. Reports of side effects and complications have been numerous. Studies of calcium assays following American Heart Association recommended dosages have shown dangerously elevated serum levels. Large retrospective clinical studies in Milwaukee and Tampa have found no evidence of improved survival with calcium chloride in asystole and EMD. A prospective randomized double-blind study comparing calcium chloride and saline controls in the Milwaukee Paramedic system for asystole and EMD using standard AHA protocols showed no statistically significant difference in resuscitation rates or long-term survival between the calcium and no-calcium groups for the rhythm of asystole. Although patients with EMD had statistically improved resuscitation rates when calcium chloride was given, only one of the patients survived to hospital discharge. Because of the low rates of resuscitation and long-term survival in patients presenting in asystole and EMD, proving that calcium chloride does not enhance survival would require large multicenter trials. However, since no controlled study has ever documented significant benefit, its routine use in asystole and EMD cannot be supported. Calcium has long been used in medical treatment of hypocalcemic and hyperkalemic states and should be administered in moribund patients who have the proper clinical history and clinical signs of hypocalcemia.

Animals↗

The risk of infection after colon injury.

We reviewed 137 patients with colon injury and applied multiple regression analysis to determine the influence of various parameters on colon-related infection. The complications of intra-abdominal abscess, wound infection, and peristomal abscess occurred in 25% of patients. The mortality rate was 3.6%, and four of five late deaths were caused by infection. Multiple regression analysis identified the amount of blood transfused, patient age, number of associated injuries, and injury to the spleen as significantly associated with infection (p less than 0.05). In the absence of these risk factors, the likelihood of infection is low, suggesting that primary repair or resection and anastomosis are safe methods of management for colon injury. When these factors are present, the risk of infection is high, and colostomy is the preferred method of management.

Abscess↗

Pre-hospital IAC-CPR versus standard CPR: paramedic resuscitation of cardiac arrests.

Recent studies evaluating interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) have demonstrated a significant increase in cardiac output, mean arterial pressure, and cerebral perfusion, as compared with standard CPR. A clinical evaluation of IAC-CPR effectiveness on resuscitation outcome has not been reported. A prospective randomized study comparing IAC-CRP with standard CPR for resuscitation of prehospital cardiopulmonary arrest was undertaken using the Milwaukee County Paramedic System. The patients were randomized following endotracheal intubation into IAC-CPR and standard CPR groups. Since October 1983, 291 patients have qualified for the study group. Of these, 146 patients had standard CPR, and 45 (31%) were successfully resuscitated. Of the 145 patients treated with IAC-CPR, 40 (28%) were successfully resuscitated. Chi-square analysis reveals no significant difference between these groups. To determine whether abdominal compression increases regurgitation, the frequency of emesis before and after intubation was analyzed. No significant difference was found between the IAC-CPR and standard CPR groups. Thus, IAC-CPR applied by paramedics in the field to patients following intubation does not improve cardiac resuscitation rates.

Abdomen↗

Effects of high infusion pressure and large-bore tubing on intravenous flow rates.

An in vitro study was conducted to determine the maximum flow rates that can be obtained with commercially available intravenous (IV) catheters, when infusion pressure and IV tubing size are modified. Standard tubing (3.2 mm ID) and two sizes of experimental large-bore tubing (5.0 mm and 6.4 mm ID) were tested with tap water and diluted packed cells (hematocrit 45) at 600 mm Hg, 300 mm Hg, and gravity flow infusion pressure. The maximum flow rate obtained was 3,158 ml/min for tap water and 3,000 ml/min for diluted packed cells. The increases in flow rates from gravity to 300 mm Hg and from gravity to 600 mm Hg are significant (P less than 0.05) and provide up to 197% and 341% increases, respectively, for all catheter/tubing combinations tested. Large-bore tubing is most effective when used in conjunction with large-bore catheters. For the 8.5 French catheter, a change from standard (3.2 mm ID) to large-bore (6.4 mm ID) tubing resulted in a statistically significant (P less than 0.05) increase in flow rate of more than 200% regardless of infusion pressure.

Fluid Therapy↗

Effects of rapid infusion with high pressure and large-bore i.v. tubing on red blood cell lysis and warming.

A prototype large-bore intravenous tubing was developed and tested. Mean flow rates for blood (Hct 45%) and tap water were determined for several catheters at 600 mm Hg, 300 mm Hg, and gravity flow and were statistically analyzed by calculating the 95% confidence intervals. The degree of hemolysis during high pressure and flow was determined by measuring the plasma free hemoglobin using the spectrophotometric method. To determine if cold banked blood can be adequately warmed at high flow rates, thermocouples were used to measure the blood temperature before and after rapid infusion through a blood warmer. Results included maximum flow rates of 1,764 mL/min for tap water, and 1,714 mL/min for blood (Hct 45%) at 600 mm Hg through the large-bore tubing and an 8.5-F catheter. Flow rates for other pressure and catheter combinations were tabulated. The plasma-free hemoglobin increased slightly compared to controls with high pressure (less than or equal to 600 mm Hg) and flow rates. The increase correlated with less than 1% red blood cell lysis in all trials. When 13 C blood was infused through a warmer, blood temperature increased to 25.3 C at the maximum flow rate of 732 mL/min. Slightly higher heat gain resulted with slower infusion rates. We conclude that the prototype large-bore tubing and up to 600 mm Hg pressure provide rapid flow rates without significant hemolysis. Blood warming may be inadequate at higher flow rates.

Blood↗

Intraosseous infusion: an alternative route of pediatric intravascular access.

Substantial difficulties can be encountered when establishing rapid intravascular access in critically ill children. The historic technique of tibial intraosseous infusion is presented as an alternate intravenous route in children less than 3 years old. Review of the literature reveals this technique to be a rapid, reliable method with an acceptably low complication rate. Substances absorbed through the marrow, flow rates, technical difficulties, and complications are discussed.

Absorption↗

Traumatic cardiac arrest: scope of paramedic services.

The challenge of the 1960s to ambulance care provision was the stimulus for the emergence of prehospital advanced life support (ALS) being provided by paramedic personnel. While services for cardiac disease have been accepted, paramedic activities for the trauma victim continue to be a concern for many trauma surgeons. The capability and success rate of treatment, and the time spent at the scene and during transport to the hospital have raised questions about the overall need for paramedic services. Our study period was from January 1, 1981, to December 31, 1982, and it covered 95 clinically dead trauma victims who were first seen and subsequently treated by paramedics working in a medically controlled emergency medical services system. Endotracheal intubation was successful in 81 of the patients (85%). Esophageal obturator airway use was viewed as unsuccessful intubation. Intravenous (IV) access utilizing 16-gauge angiocaths was placed successfully by a peripheral or jugular vein in 70 patients (74%). Thirty-three patients averaged 860 mL volume infusion (30 to 3,000 mL). Average scene time was 22 minutes. Scene time of patients with unsuccessful IV and endotracheal intubation was 14 minutes (P = .07). Fourteen patients (14.7%) were admitted to the operating room or intensive care unit. Only three of the study group (3.2%) survived.

Adolescent↗

The effectiveness of calcium chloride in refractory electromechanical dissociation.

The effectiveness of calcium in electromechanical dissociation (EMD) has been challenged. Retrospective studies have been contradictory. To determine its effectiveness a prospective, randomized, blinded study comparing calcium chloride and saline in refractory EMD was carried out in the pre-hospital setting from October 1982 to October 1983. Only patients who had received epinephrine and bicarbonate and were refractory were entered in the study. All trauma and pediatric arrests were excluded. Ninety patients presented in refractory EMD. Overall, eight of 48 who received calcium were resuscitated successfully in the field; two of 42 who received saline were resuscitated successfully (P less than .07). A successful resuscitation was defined as the conveyance of a patient with a pulse and a rhythm to an emergency department. Patients were analyzed for age, sex, and witnessing of arrest. There was no statistical difference in demographic data. When the group of EMD patients was broken down into subgroups based on the width of QRS, it was noted that patients with a QRS width less than 0.12 did not respond to calcium, whereas the successfully resuscitated in the group with widened QRS or ischemic changes (N = 70) was eight of 39, compared with one of 31 not receiving calcium (P less than .028). Only one patient who was resuscitated successfully was discharged from the hospital alive. Calcium has been shown to be effective in the cardiac resuscitation of patients in refractory EMD. There may be a subset of patients with widened QRS complexes or ischemic changes who will benefit to a greater extent from the use of calcium chloride.

Adult↗

Lack of effectiveness of calcium chloride in refractory asystole.

The effectiveness of calcium chloride in asystole has been challenged; retrospective studies have not supported its use. We conducted a prospective, randomized, blinded study comparing the effectiveness of calcium chloride with saline in the prehospital paramedic setting. Seventy-three patients who had received epinephrine, bicarbonate, and atropine and were in refractory asystole were included in the study, which was conducted from October 1982 to October 1983. Traumatic and pediatric arrests were excluded. The successful resuscitation rate was three of 39 in the calcium group versus one of 34 in the saline group (P less than .37). A successful resuscitation was defined as the conveyance of a patient with a pulse and a rhythm to an emergency department. Groups were analyzed for sex, age, and witnessed arrests. There was no statistically significant difference between the groups. No patient who was resuscitated successfully in the field was discharged from the hospital alive. We conclude that calcium chloride is not of value in resuscitating patients from refractory asystole in the prehospital cardiac arrest setting.

Aged↗

The relationship of the level of training and area of medical specialization with registrant performance in an advanced trauma life-support course.

Approved advanced trauma life-support (ATLS) programs were given to 160 residents and practitioners of various specialties, utilizing a standardized 50-item, multiple-choice posttest. Level of training (practitioner v resident) and area of medical specialization with registrant performance on total score and in specific subcontent areas of ATLS were evaluated by subjecting total and subcontent percent scores to a two-way analysis of variance and Newman-Keuls pairwise comparisons. Practitioners outperformed the residents in the subcontent area of abdominal injuries, P less than .05. In specialization, emergency medicine outperformed internal medicine specialists, P less than .05. Pairwise differences among specialists were not statistically significant. In airway problems, surgeons and internists were outperformed by emergency medicine, whereas in burns, emergency medicine and family practitioners significantly outperformed the surgeons. Emergency medicine outperformed internal medicine, P less than .05, in subcontent area of extremity injuries. We conclude that registrants are likely to benefit from an ATLS course, but preliminary evidence would seem to justify some "tailoring" of the ATLS curriculum for different registrant specialty groups.

Curriculum↗

Bystander CPR in prehospital coarse ventricular fibrillation.

Prehospital bystander cardiopulmonary resuscitation (CPR) was studied to determine if it affected the outcome of defibrillation. Four hundred twenty-one consecutive witnessed cardiopulmonary arrests presenting with the initial rhythm of coarse ventricular fibrillation treated by the Milwaukee County Paramedic System from January 1980 to June 1982 were analyzed. Pediatric, trauma, and poisoning patients and those receiving intravenous or endotracheal medications before defibrillation (58) were excluded. Immediate professional bystander CPR (physician, nurse, EMT) and citizen bystander CPR were compared to a control group receiving no bystander CPR until arrival of EMS personnel. A successful defibrillation occurred if defibrillation prior to administration of medication produced an effective cardiac rhythm with pulses. Eighty-eight of the 363 remaining patients (24%) converted with initial defibrillations. While the group receiving professional bystander CPR had a higher successful defibrillation rate than did the no-CPR group (35% vs 22%, P less than .04), citizen bystander CPR and no-CPR groups had similar successful defibrillation rates (24% vs 22%, no significant difference). One hundred eighty-six of the 363 patients (51%) were transported to a hospital with a rhythm and a pulse (a successful resuscitation). Ninety-seven of the 363 patients (27%) were discharged alive from the hospital (a save). Patients who were converted successfully using initial "quick-look" defibrillations were far more likely to be successfully resuscitated (79/88 [90%] vs 107/275 [39%], P greater than .0001) and to be discharged alive from the hospital (54/88 [61%] vs 43/275 [16%], P greater than .0001) than were those who required further advanced cardiac life support techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

"PALS for life!" A required trauma-oriented pediatric advanced life support course for pediatric and emergency medicine housestaff.

While advanced cardiac life support (ACLS) and advanced trauma life support (ATLS) courses have become accepted standards for physicians who care for the critically ill and injured patient, only recently have pediatric advanced life support (PALS) courses been developed. The American Academy of Pediatrics has shown renewed interest in pediatric cardiopulmonary arrest after impressive gains made in adult resuscitation. The American Heart Association filled a void by including new chapters on Pediatric and Neonatal Resuscitation in the Textbook of Advanced Cardiac Life Support, 1981. A joint committee of AHA and AAP is seeking to unify course objectives and materials for standard curriculum. Because trauma is the most common cause of death and disability in children, pediatric trauma life support measures should be incorporated into any program directed toward emergency physicians and pediatricians who function in an emergency department or rural primary care setting. The Department of Pediatrics and Surgery and its division of Emergency Medicine has developed and implemented a PALS curriculum which is different from most other programs in that emphasis has been placed on pediatric trauma in addition to traditional cardiac (ACLS) resuscitation. This 20-hour program combines a modified ACLS curriculum with specific pediatric trauma lectures and laboratory sessions. It includes a canine surgical procedure lab and modified ATLS skill stations. At the completion of the course, students are eligible for ACLS certification. In the two years in which the course was given, 39 pediatric houseofficers were enrolled in the course.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

Experimental cervical spine injury model: evaluation of airway management and splinting techniques.

We evaluated airway management maneuvers and the effects of cervical splinting on a model of an injured spinal column. X-ray films of a fresh cadaver verified a normal cervical spine. C5-C6 instability was created surgically and documented radiologically with flexion and extension maneuvers. Basic and advanced airway techniques were performed and were documented radiologically. The procedures were then repeated using different types of splinting. Chin lift, jaw thrust, esophageal obturator airway (EOA), and endotracheal intubation can cause extension, widening, and/or anterior subluxation. A two-piece, semirigid soft cervical collar may minimize flexion but not extension of the spine. With the Velcro in back, soft collars minimize flexion; with Velcro in front, they minimize extension. Standard nonsurgical airway management techniques appear to aggravate preexisting injuries. The soft collar and semirigid collar do little to prevent movement, and their presence may serve only as a warning to physicians that a neck injury may be present.

Cervical Vertebrae↗

Effect of circumferential pneumatic compression devices on digital flow.

We reviewed the effects of circumferential pneumatic compression suits (CPCS) when applied to normal and ischemic limbs without prior application of prehospital orthopedic traction devices beneath the garment. The digital arterial toe pressures of 11 normal and six claudicating limbs were measured with the trouser applied and the limbs pressurized to 40, 60, 80, and 100 mm Hg. In addition, normal limbs had the Hare traction device and the Sager splint applied prior to application of the trouser and retesting of the digital arterial flow. We conclude that CPCS prevents flow into the limbs, and this may potentiate the development of compartment syndromes in the previously traumatized or ischemic limbs. Normal limbs with traction devices already applied may be at a higher risk for compartment syndromes, and we suggest that patients with fractured limbs who are in need of CPCS not have the traction device applied.

Blood Pressure↗

Interposed abdominal compression CPR versus standard CPR in prehospital cardiopulmonary arrest: preliminary results.

Recent studies evaluating interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) have demonstrated a significant increase in cardiac output, mean arterial pressure, and cerebral perfusion compared with standard CPR. A clinical evaluation of IAC-CPR effectiveness on resuscitation outcome has not been reported. A prospective, randomized study comparing IAC-CPR with standard CPR for resuscitation of prehospital cardiopulmonary arrest was developed utilizing the Milwaukee County Paramedic System. When the paramedics arrive, standard CPR is initiated or continued, and countershocks are delivered when appropriate. The patients are randomized into IAC-CPR and standard CPR groups immediately following endotracheal intubation. Abdominal compression force is standardized to 100 mm Hg +/- 20 mm Hg by using a simple airfilled bladder and gauge to monitor each compression. Resuscitations are conducted according to standard advanced cardiac life support guidelines through continuous radio-telemetry contact with a base physician. Since October 1983, 140 patients have qualified for the study group. Seventy patients had standard CPR and 30% (21/70) were admitted to the emergency department with a rhythm and pulse, as were 34% (24/70) of the patients treated with IAC-CPR. The difference between study groups was not significant. To determine if abdominal compression increases regurgitation, the frequency of emesis before and after intubation was analyzed. No significant difference was found between the IAC-CPR and standard CPR groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗