Soluble complement receptor-1 protects heart, lung, and cardiac myofilament function from cardiopulmonary bypass damage.

BACKGROUND: Host defense system activation occurs with cardiopulmonary bypass (CPB) and is thought to contribute to the pathophysiological consequences of CPB. Complement inhibition effects on the post-CPB syndrome were tested with soluble complement receptor-1 (sCR1). METHODS AND RESULTS: Twenty neonatal pigs (weight 1.8 to 2.8 kg) were randomized to control and sCR1-treated groups. LV pressure and volume, left atrial pressure, pulmonary artery pressure and flow, and respiratory system compliance and resistance were measured. Preload recruitable stroke work, isovolumic diastolic relaxation time constant (tau), and pulmonary vascular resistance were determined. Pre-CPB measures were not statistically significantly different between the 2 groups. After CPB, preload recruitable stroke work was significantly higher in the sCR1 group (n=5, 46.8+/-3.2x10(3) vs n=6, 34.3+/-3.7x10(3) erg/cm(3), P=0.042); tau was significantly lower in the sCR1 group (26.4+/-1.5, 42.4+/-6. 6 ms, P=0.003); pulmonary vascular resistance was significantly lower in the sCR1 group (5860+/-1360 vs 12 170+/-1200 dyn. s/cm(5), P=0.009); arterial PO(2) in 100% FIO(2) was significantly higher in the sCR1 group (406+/-63 vs 148+/-33 mm Hg, P=0.01); lung compliance and airway resistance did not differ significantly. The post-CPB Hill coefficient of atrial myocardium was higher in the sCR1 group (2.88+/-0.29 vs 1.88+/-0.16, P=0.023). CONCLUSIONS: sCR1 meaningfully moderates the post-CPB syndrome, supporting the hypothesis that complement activation contributes to this syndrome.

Aortoesophageal fistula: a comprehensive review of the literature.

Aortoesophageal fistula (AEF) is a relatively rare but life-threatening cause of upper gastro-intestinal bleeding. The clinical characteristics of AEF are so unique that a presumptive bedside diagnosis can be made at the time of presentation. In the past decade, surgical management has improved to the point that cure is now possible. For these reasons, we have reviewed the literature. We summarize our findings with respect to the etiology and clinical characteristics of AEF. Further, we discuss the diagnostic modalities that may be used to confirm the diagnosis, and the therapeutic modalities available to slow the hemorrhage, so as to allow time to correct the anatomic defect.

Liquid ventilation improves pulmonary function and cardiac output in a neonatal swine model of cardiopulmonary bypass.

OBJECTIVE: Neonatal and infant cardiopulmonary bypass results in multiorgan system dysfunction. Organ protective strategies have traditionally been directed at the myocardium and brain while neglecting the sometimes severe injury to the lungs. We hypothesized that liquid ventilation would improve pulmonary function and cardiac output in neonates after cardiopulmonary bypass. METHODS: Twenty neonatal swine were randomized to receive cardiopulmonary bypass with or without liquid ventilation. In the liquid-ventilated group, a single dose of perflubron was administered before bypass. The control group was conventionally ventilated. Each animal was placed on nonpulsatile, hypothermic bypass. Low-flow cardiopulmonary bypass was performed for 60 minutes. The flow rate was returned to 125 ml/kg per minute, and after warming to 37 degrees C, the animals were removed from bypass. Hemodynamic and ventilatory data were obtained after bypass to assess the effects of liquid ventilation. RESULTS: Without liquid ventilation, cardiopulmonary bypass resulted in a significant decrease in cardiac output, oxygen delivery, and static pulmonary compliance compared with prebypass values. Input pulmonary resistance and characteristic impedance increased in these control animals. At 30, 60, and 90 minutes after bypass, the animals receiving liquid ventilation showed significantly increased cardiac output and static compliance and significantly decreased input pulmonary resistance and characteristic impedance compared with control animals not receiving liquid ventilation. CONCLUSIONS: Liquid ventilation improved pulmonary function after neonatal cardiopulmonary bypass while increasing cardiac output. The morbidity associated with cardiopulmonary bypass may be significantly reduced if the adverse pulmonary sequelae of bypass can be diminished. Liquid ventilation may become an important technique to protect the lungs from the deleterious effects of cardiopulmonary bypass.

Encircling endocardial ventriculotomy for refractory ischemic ventricular tachycardia. II. Effects on regional myocardial blood flow.

Previous experimental studies of the encircling endocardial ventriculotomy (EEV) have shown a significant alteration of normal local electrical activity within the encompassed region. Although this procedure may result in isolation of ventricular arrhythmias, the data are more suggestive of a less specific effect on regional myocardial blood flow. This study examines the effect of EEV on local myocardial blood flow using the radioactive tracer microsphere technique in 10 dogs. Flows were determined before and after an EEV with the animals on cardiopulmonary bypass at controlled perfusion pressures, temperatures, and heart rates. Blood flow was studied at subepicardial and subendocardial levels inside, outside, and bordering the EEV. Prior to performance of the EEV, subepicardial blood flow in the left ventricular myocardium ranged from 0.81 +/- 0.07 to 0.89 +/- 0.08 ml/gm/min. Subendocardial flows ranged from 0.80 +/- 0.07 to 0.91 +/- 0.09 ml/gm/min. There was no significant difference between any of the flows across each respective layer of myocardium. Following the EEV procedure, blood flow to the subendocardium within the EEV fell to 0.33 +/- 0.07 ml/gm/min, while flow to the subendocardium of the normal regions of the same hearts actually increased to 1.21 +/- 0.23 ml/gm/min. Similar changes occurred at subepicardial levels, with flow at the center of the EEV falling to 0.66 +/- 0.10 ml/gm/min despite a tendency for normal subepicardial flow to increase to 1.78 +/- 0.24 ml/gm/min. Superimposed ischemia to the EEV-encompassed myocardium, created by occlusion of the distal left anterior descending coronary artery (LAD), accentuated this abnormality by demonstrating that the region continues to receive some flow from epicardially based coronary vessels. The data from this study show that the EEV decreased regional blood flow to the encompassed myocardium and suggests that myocardial ischemia may be responsible for ablation of the delicate re-entrant mechanisms that sustain ventricular tachyarrhythmias.

Encircling endocardial ventriculotomy for refractory ischemic ventricular tachycardia. III. Effects on regional left ventricular function.

In order to assess the effects of the encircling endocardial ventriculotomy (EEV) on regional left ventricular function, we cannulated seven adult mongrel dogs for cardiopulmonary bypass. Two pairs of miniature pulse-transit transducers were placed in mid-myocardium of the left ventricle, one pair in a region that would later be encompassed by an EEV and the other pair in a region of remote normal myocardium. Pressure-dimension data were analyzed during vena caval occlusions (after volume loading) both on and off cardiopulmonary bypass and both before and after performance of an EEV. The EEV results in a significant decrease in diastolic compliance of the encompassed myocardium. No significant compliance changes occurred in the control regions of the same hearts. This change in regional diastolic compliance is partially responsible for a loss of systolic excursion within the EEV-encompassed region and may help to explain the severe left ventricular dysfunction that has been observed in some patients following an EEV.

Encircling endocardial ventriculotomy for refractory ischemic ventricular tachycardia. I. Electrophysiological effects.

The direct endocardial surgical techniques introduced for the treatment of refractory ischemic ventricular tachyarrhythmias have resulted in decreased surgical mortality rates and increased success rates in comparison to previous indirect techniques. Since the mechanism of action of one of these new techniques, the encircling endocardial ventriculotomy (EEV), is unknown, the present study was designed to clarify the electrophysiological effects of this procedure. Epicardial and intramural electrophysiology was studied in 18 dogs before and after undergoing an EEV. In the absence of induced myocardial ischemia, the procedure caused an epicardial conduction delay of 23 +/- 3 msec (p less than 0.0001) across the boundaries of the incision. When the EEV enriched acutely ischemic myocardium, it was capable in certain instances of isolating spontaneous ventricular electrical activity to the myocardium encompassed by the incision and thereby protecting the remainder of the heart from the arrhythmia. The EEV resulted in total ablation of all (2 Mv/msec) electrical activity at 20 of 48 (42%) subendocardial electrode sites and at 12 of 44 (27%) subepicardial sites monitored within the encompassed myocardium. These data suggest that although the EEV may be capable of isolating ischemic ventricular tachyarrhythmias to the encompassed myocardium, it most commonly ablates the anatomic-electrophysiological substrate necessary for the genesis and perpetuation of these arrhythmias.

Effect of nicotinic acid conjugated to DNA-transfecting complexes targeted at the transferrin receptor of HeLa cells.

A conjugate consisting of streptavidin (biotinylated transferrin)-biotinylated polylysine for DNA delivery to cells was modified by partial nicotinylation of the polylysine component of the conjugate and used for transfection studies. A conjugate of biotin10-nicotinyl60-polylysine250 containing 60 weakly basic nicotinyl (pyridine-3-carboxyl) residues was prepared. The design of the modified polylysine was directed to the possible binding of H+ ions in the endosome-lysosomal vesicles (pH 5-6) by the nicotinyl groups, thus circumventing the use of chloroquine. The results obtained, however, while showing a 5- to 6-fold increase in luciferase transfection activity still necessitated an absolute requirement for chloroquine. A further polylysine conjugate containing a larger number of nicotinyl residues, biotin10-nicotinyl120-polylysine250, also was prepared and studied. This macromolecule stimulated luciferase activity to a small extent and was also dependent on chloroquine. Smaller biotinylated polylysine100 conjugates containing nicotinyl groups were also prepared. These were biotin10-nicotinyl30-polylysine100, and biotin10-nicotinyl60-polylysine100, respectively. Both substances, however, gave opaque, hazy aqueous solutions with precipitates on standing and could not be used for further experimental work. The results indicate that the introduction of weakly basic nicotinyl (pyridine-3-carboxyl) groups onto polylysine250 give conjugates that are unable to replace the lysosomotrophic agent chloroquine in the HeLa cell sysem studied. A 5- to 6-fold increase in luciferase activity, however, was found with biotin10-nicotinyl60-polylysine250.

A paradigm for multidisciplinary disaster research: the Oklahoma City experience.

The objective of this article is to describe the creation and operation of a multidisciplinary group to examine the Oklahoma City (OKC) bombing. The OKC bombing presented an opportunity to study a major disaster within 2 days of the incident. The Disaster Health Studies Group (DHSG) was created to facilitate this effort. The creation, organization, and operation of the DHSG is outlined. In addition the mission statement, participants, communications, political empowerment, data preservation and collection, data ownership, patient rights, threats to the DHSG, media interactions, funding, the institutional review board process, and results reporting will be detailed. The 22 projects of the DHSG are listed. In conclusion, four main findings are examined: 1) A multidisciplinary disaster study group is feasible and can be rapidly organized; 2) certain organizations and institutions form a core group for facilitation of the research effort; 3) specific issues must be addressed in order for the group to succeed; and 4) the group leader should have disaster expertise and be committed to the multidisciplinary process.

Time analysis of consult service emergency department admission process compared with emergency medicine service admission process.

This prospective case-controlled study was performed to compare the time intervals of a consult emergency department (ED) admission process with an emergency medicine (EM) service admission process. During March 1994, the consultant services admitted 307 patients for hospitalization at an urban tertiary academic ED with an EM residency; in April 1994, the EM service admitted 264 patients. The times measured were: 1) triage to examination room; 2) room to first physician contact; and 3) emergency physician contact to admit request. Data analysis was by mode and Wilcoxon tests. We analyzed 537 evaluable admissions. The mode for consultant process was 205 min, and the mode for emergency medicine admissions was 158 min from first physician contact to admit request, for a 47-min difference. All patients arrived stable to an inpatient bed; none was transferred to the Intensive Care Unit or to an operating room in the first 24 h. Concordance of the ED admitting impression and the hospital discharge diagnosis was 99% (259/264). We conclude that in selected tertiary academic EDs, admission of all patients by the EM service is more efficient than a consultant-admission process. Outcomes show the EM admission process may be employed safely and with accurate patient diagnosis.

Bedside measurement of D-dimer in the identification of bacteremia in the emergency department.

The objective of this pilot study was to determine the clinical utility of the SimpliRed D-dimer bedside assay to identify patients with bacteremia in a university hospital Emergency Department. We tested 265 patients and compared blood culture results with a novel D-dimer semiquantitative whole blood assay. Bacteremia was confirmed in 25/262 patients. Sensitivity of D-dimer assay was 66.7% for Gram-positive bacteremia and 61.5% for Gram-negative bacteremia with negative predictive value of 98% for Gram-positive and 96% for Gram-negative bacteremia patients. Measurement of D-dimer appears to be of value in identifying patients at low risk for bacteremia and can be accomplished rapidly using a whole blood semiquantitative bedside assay. Although increases in D-dimer are not detected in all patients subsequently documented to have bacteremia on a single sampling, the results of this and other earlier studies suggest assay of D-dimer is useful in rapid differentiation of patients with bacteremia from those who have no bacteremia using blood culture positivity as the standard for bacteremia.

Introduction to smart card technology and initial medical application.

Smart card technology is the name applied to the use of a plastic card with an embedded computer chip. Recent development of smart card software has allowed storage and retrieval of medical information, affording the opportunity to provide a standardized, portable, accessible medical record for use in prehospital and emergency department patient encounters. We describe the smart card concept and its initial deployment in a section of a large Midwestern urban area.

The radical.

When her colleagues suggested to Gayle Quick that it was about time they had some enrolled nurse representation on the English. National Board, she took the plunge and is now, at 25, the youngest member serving on it.

Emergency department medication and drug interaction evaluation.

The emergency department evaluation had two primary objectives: 1) to determine the accuracy of the oral medication history given at arrival at the emergency department and 2) to determine how often the emergency department physician may prescribe medications which when taken with current medications, may cause a potential drug interaction. Data were collected from 228 emergency department visits of clinic patients 65 years old and older. The average number of medications reported by the patients' medication history was 3.0 +/- 2.3 (range 0-13). The number of medications the patient "forgot" was 1.3 +/- 1.8 (range 0-9). A complete medication history was given by 50.4% of patients. There was an upward trend that correlated with an increased chance for an incomplete medication history as the total number of current medications increased. The rate of a potentially significant drug interaction between a newly prescribed medication in the emergency department and current medications was 3.4% for patients receiving a new medication.

A novel antidote-controlled anticoagulant reduces thrombin generation and inflammation and improves cardiac function in cardiopulmonary bypass surgery.

Heparin and protamine are the standard anticoagulant-antidote regimen used in almost every cardiopulmonary bypass (CPB) procedure even though both are associated with an array of complications and toxicities. Here we demonstrate that an anticoagulant aptamer-antidote pair targeting factor IXa can replace heparin and protamine in a porcine CPB model and also limit the adverse effects on thrombin generation, inflammation, and cardiac physiology associated with heparin and protamine use. These results demonstrate that targeting clotting factors upstream of thrombin in the coagulation cascade can potentially reduce the perioperative pathologies associated with CPB and suggest that the aptamer-antidote pair to FIXa may improve the outcome of patients undergoing CPB. In particular, this novel anticoagulant-antidote pair may prove to be useful in patients diagnosed with heparin-induced thrombocytopenia or those who have been sensitized to protamine, particularly patients who have insulin-dependent diabetes.

A randomized clinical trial of rib belts for simple fractures.

The authors present a pilot study in which 20 patients with simple rib fractures were randomized prospectively into two treatment groups. One group received ibuprofen and the other group ibuprofen plus a rib belt for analgesia. There were no statistically significant differences observed in pulmonary function testing between the groups at initial visit, 48 hours, or 5 days. Atelectasis developed in four patients, two in each treatment group; there were no cases of pneumonitis. Patients with displaced rib fractures experienced a higher rate of hemo- or pneumothorax than did those with nondisplaced fractures (5/10 v 1/10). Patients with displaced fractures who used rib belts experienced a higher rate of hemothorax than those using oral analgesia alone (4/6 v 1/4). Patients using rib belts uniformly reported a significant amount of additional pain relief. The clinician can use a rib belt to provide additional comfort to the patient with fractured ribs without apparent additional compromise to respiratory parameters. A further study stratifying displaced and nondisplaced fractures has been initiated to clarify the possible contributing roles of displaced rib fractures and the rib belt in patients with displaced fractures.

Prolonged asystolic hyperkalemic cardiac arrest with no neurologic sequelae.

We report the case of a 70-year-old man who developed cardiac arrest secondary to hyperkalemia that complicated severe chronic renal failure due to obstructive uropathy. The patient experienced electromechanical dissociation and approximately 26 minutes of asystole after which the resuscitation was suspended. However, 8 to 10 minutes after declaration of death, the patient was noted to have developed spontaneous return of circulation as the emergency department personnel were preparing to transport him to the morgue. The patient survived and was discharged without apparent neurologic sequelae. This case demonstrates the challenges facing physicians to predict the outcome of hyperkalemic cardiac arrest based on usual parameters. It also highlights the relative paucity of resuscitation guidelines to assist in the management of this medical emergency.

An emergency department radiology audit procedure.

An audit was done to ascertain the concordance of radiographic interpretation by the emergency physician and the radiologist. In 8,021 radiographic procedures during the two-month study, concordance of interpretation was found in 97.6%. The primary area of interpretation difficulty was chest radiographs. Specifically, there was limited agreement (10 of 45 films, 22%) regarding the reading of inflammatory processes. Despite this, 40 of the 45 patients (89%) whose chest radiographs were reviewed received proper therapy. The findings in five radiographs were deemed to be significant enough to possibly lead to changes in management.

Incarcerated paraesophageal hernia.

The case of an 80-year-old woman with an incarcerated paraesophageal hernia is presented. Among diaphragmatic hernias, the paraesophageal or type II hernia occurs with an incidence of 5%, sliding or type I hernia occurs with an incidence of 95%. Incarcerated paraesophageal hernia is a surgical emergency requiring rapid decompression and reduction to minimize catastropic consequences of hemorrhage, perforation, and visceral infarction. The clinical presentation and diagnostic workup of the patient with incarcerated type II diaphragmatic hernia are discussed.

Hernia en masse.

Described is the case of a patient who developed symptoms compatible with small bowel obstruction approximately 16 hours after a difficult self-performed left inguinal hernia reduction. Exploratory laparotomy was performed, and release of an incarcerated loop of ileum was performed. A large inguinal hernia defect also was found, and this was repaired with a Cooper's ligament repair. The patient recovered uneventfully.

Occult bacteremia in the emergency department: diagnostic criteria for the young febrile child.

We studied a selected series of febrile infants (N = 201) in an attempt to prospectively identify risk factors for bacteremia. Infants with fever less than 39.4 C, vomiting and diarrhea, croup, or viral exanthem or enanthem were not included. Twenty-one infants (9.5%) had positive blood cultures despite the initial judgment of their physician that only viral illness or localized bacterial infection existed. WBC count of more than 15,000 correlated with bacteremia, with a sensitivity of 0.71 and a specificity of 0.73. Extensive multivariate linear regression analysis attempting to increase predictive values was completed. The combination of fever higher than 39.4 C present for more than 12 hours and absolute polymorphonuclear count of more than 9,000 cells/mm3 had a sensitivity of 0.62 and a specificity of 0.78 for bacteremia. Descriptive statistics for groups with and without bacteremia are summarized. We have defined prospectively a population of infants with a high probability of bacteremia and a lower probability of viral illness. Identification of such a group is useful to the emergency physician because early antibiotic therapy may lessen morbidity and mortality. We conclude that an easily obtained data base may be useful in the prospective identification of those at risk for bacteremia.