Mortality from isolated civilian penetrating extremity injury.

BACKGROUND: Although studies have ascertained that ten percent of soldiers killed in battle bleed to death from extremity wounds, little data exists on exsanguination and mortality from extremity injuries in civilian trauma. This study examined the treatment course and outcomes of civilian patients who appear to have exsanguinated from isolated penetrating extremity injuries. METHODS: Five and 1/2 years' data (Aug 1994 to Dec 1999) were reviewed from two Level I trauma centers that receive 95% of trauma patients in metropolitan Houston, TX. Records (hospital trauma registries, emergency medical system (EMS) and medical examiner data) were reviewed on all patients with isolated extremity injuries who arrived dead at the trauma center or underwent cardiopulmonary resuscitation (CPR) or emergency center thoracotomy (ECT). RESULTS: Fourteen patients meeting inclusion criteria were identified from over 75,000 trauma emergency center (EC) visits. Average age was 31 years and 93% were males. Gunshot wounds accounted for 50% of the injuries. The exsanguinating wound was in the lower extremity in 10/14 (71%) patients and proximal to the elbow or knee in 12/14 (86%). Ten (71%) had both a major artery and vein injured; one had only a venous injury. Prehospital hemorrhage control was primarily by gauze dressings. Twelve (86%) had "signs of life" in the field, but none had a discernable blood pressure or pulse upon arrival at the EC. Prehospital intravenous access was not obtained in 10 patients (71%). Nine patients underwent ECT, and nine were initially resuscitated (eight with ECT and one with CPR). Those undergoing operative repair received an average of 26 +/- 14 units of packed red blood cells. All patients died, 93% succumbing within 12 hours. CONCLUSION: Although rare, death from isolated extremity injuries does occur in the civilian population. The majority of injuries that lead to immediate death are proximal injuries of the lower extremities. The cause of death in this series appears to have been exsanguination, although definitive etiology cannot be discerned. Intravenous access was not obtainable in the majority of patients. Eight patients (57%) had bleeding from a site that anatomically might have been amenable to tourniquet control. Patients presenting to the EC without any detectable blood pressure and who received either CPR or EC thoracotomy all died.

Life science research in space brings health on Earth.

NASA: Leading scientists and physicians review groundbreaking research that is leading the way to better health care for astronauts and new treatments for medical problems on Earth. This research includes the development and testing of a new Ventricular Assist Device for patients with heart failure awaiting heart transplantation; advancements in telemedicine that bring medical care to remote areas on Earth and aid in the diagnosis and treatment of illness during space flight; advanced technologies, such as a miniature mass spectrometer, cardiac ultrasound equipment, bone imaging, non-invasive High-Intensity Focused Ultrasound, non-invasive techniques for blood and tissue chemistry measurements; and advances in the treatment of spinal cord injuries.^ieng

Congestive heart failure. A new milestone for a better life.

Congestive heart failure (CHF) represents the 1st cause of death in the civil world. Despite considerable advances in the diagnosis and medical treatment of CHF, this condition remains a real "malignant" disease. The cardiac transplantation (CT) remains "gold standard" option for the treatment of patients with severe CHF in all age group; but only a small number of patients can receive it due to scarcity of donor organs. The increased successful clinical experience with the ventricular assist device (VAD) confirmed the indisputable importance of long-term mechanical circulatory support for patients who suffer acute hemodynamic deterioration. Over the past years, several miniaturized continuous flow VAD have been developed for clinical use. The authors report the data of worldwide and particularly Italian experience about middle and long-term pump performance in patients supported with axial-flow pump MicroMed DeBakey VAD in the bridge to cardiac transplantation setting.

Postoperative course of S-100B protein and neuron-specific enolase in patients after implantation of continuous and pulsatile flow LVADs.

BACKGROUND: In the early post-operative period after implantation of a continuous flow left ventricular assist device (LVAD) a non-pulsatile flow occurs. We compared the post-operative time-courses of protein S-100B (S100B) and neuron-specific enolase (NSE) as biochemical markers of brain injury in patients after implantation of a continuous flow LVAD and patients receiving a pulsatile flow LVAD. METHODS: Since 1998 the continuous flow DeBakey VAD has been implanted in 8 patients at our institution. For comparison purposes, a group of 7 consecutive patients in whom a pulsatile Novacor N100 LVAD was implanted were investigated. In both groups cardiopulmonary bypass (CPB) with cardiotomy suction was used. S100B and NSE were measured in serum pre-operatively, 4 hours after CPB, and on days 1, 3, 7, and 14 after implantation of the LVAD. A neurologic examination was performed pre-operatively and post-operatively on days 3 and 14. RESULTS: No differences were found between groups in pre-operative characteristics. The analysis of variance with repeated measurements for S-100B and NSE showed significant time effects (p = 0.004, p = 0.009, respectively) but no group effects (p = 0.06, p = 0.26, respectively) and no interaction between groups and time (p = 0.12, p = 0.48, respectively). The pre-operative serum level of S100B was significantly higher (p = 0.03) in the DeBakey VAD group. The pre-operative serum level of NSE was similar in the 2 groups (p = 0.7). In both groups there was a significant increase of S100B and NSE immediately after surgery (S100B: p = 0.006, p = 0.019; NSE: p = 0.01, p = 0.001). The values returned to pre-operative levels in the DeBakey VAD group on day 1 after implantation and in the Novacor group for S100B on day 3 and NSE on day 1. Post-operatively the mean values of S100B and NSE in the DeBakey VAD group compared with the Novacor group were significantly elevated only on day 3 (p = 0.005, p = 0.023).No neurologic complications were noted in patients with a continuous flow LVAD, whereas in the pulsatile LVAD group 2 patients presented neurologic abnormalities during the study period. CONCLUSIONS: The similar course of biochemical markers of brain damage in both groups may indicate that the non-pulsatile flow in the early post-operative period does not lead to increased brain injury or permeability of the brain blood barrier.Elevated levels of S100B and NSE in the post-operative period can be used as diagnostic markers of brain injury in patients after implantation of both types of LVAD.

Transcranial detection of microembolic signals in patients with a novel nonpulsatile implantable LVAD.

Mechanical ventricular assist devices (VAD) have become an accepted therapy for the support of patients in severe heart failure. With the devices presently available, the incidence of thromboembolic complications is high. Since November 1998, we have used the DeBakey VAD (MicroMed, Inc., Woodlands, TX). To detect the effect of this VAD on the appearance of microthrombi or bubbles from cavitation, we measured Microembolic Signals (MES) with transcranial Doppler in patients after the implantation of the DeBakey VAD. Transcranial Doppler studies were performed with the MULTI-DOP X4 device with two 2 MHz probes (for the left and right middle cranial arteries [MCA]) in five patients preoperatively and during 10 weeks after VAD implantation. Both MCAs were monitored simultaneously for 60 minutes in 10 sessions in each patient. The detection and analysis of MES was performed in accordance with the technique and criteria described by the international consensus group. No MES were noted during the study period in four patients. In one patient with preoperatively noted MES the prevalence of MES postoperatively was 50%. The high speed rotating impeller of the DeBakey VAD did not produce any detectable microthrombi or bubbles from cavitation effects.

Complications common to ventricular assist device support are rare with 90 days of DeBakey VAD support in calves.

The DeBakey VAD is a miniaturized, electromagnetically driven axial flow pump intended for long-term ventricular assist. Safety and performance data from six calves implanted with the complete DeBakey VAD system are reported elsewhere; here we describe complications and necropsy findings for these same six animals, all of which survived 90 days. The study was conducted according to a uniform protocol, which included anticoagulation and antibiotic prophylaxis. Clinical complications tracked included bleeding, cardiovascular abnormalities (e.g., arrhythmias, tachycardia unrelated to pain, bradycardia), hemolysis, hepatic dysfunction, renal dysfunction, thromboembolism (neurologic or peripheral), or infection. Each adverse event was retrospectively categorized with regard to severity (mild, moderate, severe) and relationship to device. Clinical findings were confirmed by necropsy. There was no evidence of systemic infection, thromboembolism, hemolysis, or renal or hepatic dysfunction in these six animals during the study period. A single adverse event was noted in each of two of the calves. Both events were considered mild according to the predefined criteria. Bleeding related to the surgical implantation procedure and requiring reoperation occurred in one animal. The other animal had evidence of a superficial infection at the exit site of the cables on the left lateral thoracic wall; the infection did not extend into the thoracic cavity. Chronic, healed small renal infarct scars were present in several animals. Mild valvular endocardiosis was observed in two calves and mild fibroelastosis was present in the endocardium at the site of the inflow cannula in three calves; however, these lesions were not considered clinically significant. No other gross or histologic abnormalities were noted at necropsy. In conclusion, calves implanted with the complete DeBakey VAD for 90 days demonstrated few complications and had no significant necropsy findings. Complications common to ventricular assist device (VAD) support (i.e., hemolysis, infection, bleeding, thromboembolism) were rare during long-term support (90 days) with the DeBakey VAD.

Right lower quadrant pain in children caused by omental infarction.

BACKGROUND: Omental infarction is a rare cause of abdominal pain, with fewer than 300 cases reported in the literature. Only 15% of reported cases occur in the pediatric population. We present our experience with 18 children diagnosed with omental infarction admitted to Texas Children's Hospital over a 15-year period. STUDY DESIGN: A retrospective review of clinical records, diagnostic images, and pathologic findings was carried out for all children diagnosed with isolated omental infarction from 1986 to 2000 in order to analyze presenting signs and symptoms, preoperative imaging, surgical management, and postoperative outcomes. RESULTS: Eighteen children were treated for isolated omental infarction. There were 12 boys and 6 girls with an average age of 7.5 years (range 2 to 13). All patients presented with acute onset of right lower quadrant pain. Only 5 of 18 (24%) had associated gastrointestinal symptoms. The average temperature at presentation was 99.4 degrees F (+/- 0.78). The average white blood cell count was 11.4 (+/- 4.4). Fourteen patients had ultrasonographys performed preoperatively: 6 of 14 incorrectly diagnosed appendicitis, 4 of 14 were nondiagnostic and 4 of 14 correctly diagnosed omental infarction. Two of 18 patients underwent computed tomography scans, which were diagnostic for omental infarction. Resection of the infarcted omentum was performed in all patients and appendectomy in 16 of 18. Thirteen patients underwent an open procedure, 5 were performed laparoscopically. There were no postoperative complications. All patients had resolution of pain postoperatively and were discharged an average of 3.0 (+/- 0.9) days after admission. CONCLUSIONS: Omental infarction is an uncommon cause of right lower quadrant pain in children and is often diagnosed as appendicitis preoperatively. Ultrasonography and computed tomography can be diagnostic. Surgical resection of the infarcted omentum results in immediate resolution of pain with no morbidity.

Pulsatile flow in patients with a novel nonpulsatile implantable ventricular assist device.

BACKGROUND: Ventricular assist devices (VADs) are an accepted therapy for patients with end-stage heart failure. The implantable devices that are available produce a pulsatile flow and are very large. In 6 patients, beginning in November 1998, we started to use the continuous-flow implantable DeBakey VAD device, which weighs 93 g. To detect the flow in peripheral vessels, we measured transcranial Doppler signals in patients after implantation. METHODS AND RESULTS: Transcranial Doppler studies were performed with the MULTI-DOP X4 device with two 2-MHz probes (for the middle cranial arteries) in 4 patients for up to 12 weeks twice weekly after implantation. The blood velocity was measured, and the pulsation index (PI) calculated. The measured pump flow and rotations per minute were registered. The preoperative echocardiographic assessment values were compared with those acquired 6 weeks after implantation. The PI increased continually in all patients after VAD implantation, left ventricular (LV) ejection fraction did not improve, but right ventricular (RV) ejection fraction after implantation improved compared with preoperative values. The LV end-diastolic diameter after implantation decreased between 11% and 46% intraindividually. There was no correlation between PI and blood pressure or, except in 1 patient, between PI and blood flow through the VAD. CONCLUSIONS: The DeBakey VAD unloads the LV, which leads to a decrease in LV end-diastolic LV diameter and to the restoration of RV function. The unloaded LV and partially recovered RV provide a nearly physiological pulsatile flow despite the continuous flow of the VAD. Pulsatility is independent of peripheral vascular resistance. The first clinical experience with the DeBakey VAD was positive and has resulted in its continued use.

Cytomegalovirus genome and the immediate-early antigen in cells of different layers of human aorta.

A number of data suggest that reactivation of cytomegalovirus (CMV) latent in arterial wall cells may contribute to atherogenesis; however, there is no direct evidence available. To address this issue, we have examined, using in situ hybridization or immunohistochemical staining, the frequency of occurrence of cells containing viral genome and of those expressing the IE 70 viral antigen in the endothelial layer and in deeper layers of human aortas with or without visible atherosclerotic lesions. Using endothelial cell cultures or tissue endothelial preparations, we found CMV-hybridizing endothelial cells in 6 of 8 grossly normal aortas and in 16 of 18 lesioned aortas. Antigen-positive endothelial cells were detected in 1 of 5 grossly normal vessels and in 6 of 7 lesioned vessels. Infected endothelial cells were abundant in areas adjacent to orifices of intercostal arteries of grossly normal aortas and in fatty spots of lesioned aortas, but no infected endothelial cells were observed in most plaques examined. In paraffin sections of grossly normal vessels, we detected CMV genome in cells adjacent to lumen and in cells randomly scattered through subendothelial intima and the media; however, no immunoreactive viral protein was found in the same tissue samples. In sections of lesioned vessels, clusters of CMV-hybridizing cells were found in the media in addition to infected cells randomly scattered through the intima and the media. In these samples of lesioned vessels, viral antigen was detected in cells adjacent to lumen and in cells clustered at the intima/media border. We found antigen-positive cells in grossly normal areas of lesioned aortas and in fatty lesions, but not in plaques of the same vessels. The data suggest that accumulation of the immediate-early CMV antigen in cells of endothelial layer and development of antigen-positive cell clusters in deeper layers of vascular wall accompany early atherogenic events in human aorta.

Frequency of coexistence of cytomegalovirus and Chlamydia pneumoniae in atherosclerotic plaques.

BACKGROUND: Cytomegalovirus (CMV) and Chlamydia pneumoniae (C. pneumoniae) antigens and DNA sequences have been demonstrated in atherosclerotic plaques by several investigators. Most significantly, CMV DNA was found both in atherosclerotic lesions as well as in uninvolved areas of aortas and carotid artery, whereas C. pneumoniae was mostly detected in advanced carotid atherosclerotic lesions. METHODS AND RESULTS: Atherosclerotic plaques removed from seventeen patients during carotid endarterectomy were analysed for the simultaneous presence of CMV and C. pneumoniae DNA sequences using polymerase chain reaction (PCR). Of the seventeen samples, nine (53%) were positive for CMV DNA sequences and seven (41%) contained C. pneumoniae DNA sequences. Four samples (24%) were positive for both CMV and C. pneumoniae DNA. CMV DNA or C. pneumoniae DNA was detected in 12 (71%) of 17 carotid plaques and 2 additional patients had high titers of antibodies to CMV. CMV DNA and C. pneumoniae DNA were found in the same tissue specimens in 4 (24%) patients. CONCLUSIONS: These results present evidence that CMV DNA and/or C. pneumoniae DNA can be detected in 71% of carotid atherosclerotic plaques and in some instances DNA of both agents in the same tissue. The possible pathogenetic role of these agents in the initiation or promotion of the development of atherosclerotic plaques deserves increased attention.

Quantification in situ of crystalline cholesterol and calcium phosphate hydroxyapatite in human atherosclerotic plaques by solid-state magic angle spinning NMR.

Because of renewed interest in the progression, stabilization, and regression of atherosclerotic plaques, it has become important to develop methods for characterizing structural features of plaques in situ and noninvasively. We present a nondestructive method for ex vivo quantification of 2 solid-phase components of plaques: crystalline cholesterol and calcium phosphate salts. Magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of human carotid endarterectomy plaques revealed (13)C resonances of crystalline cholesterol monohydrate and a (31)P resonance of calcium phosphate hydroxyapatite (CPH). The spectra were obtained under conditions in which there was little or no interference from other chemical components and were suitable for quantification in situ of the crystalline cholesterol and CPH. Carotid atherosclerotic plaques showed a wide variation in their crystalline cholesterol content. The calculated molar ratio of liquid-crystalline cholesterol to phospholipid ranged from 1.1 to 1.7, demonstrating different capabilities of the phospholipids to reduce crystallization of cholesterol. The spectral properties of the phosphate groups in CPH in carotid plaques were identical to those of CPH in bone. (31)P MAS NMR is a simple, rapid method for quantification of calcium phosphate salts in tissue without extraction and time-consuming chemical analysis. Crystalline phases in intact atherosclerotic plaques (ex vivo) can be quantified accurately by solid-state (13)C and (31)P MAS NMR spectroscopy.

Patterns of atherosclerosis: effect of risk factors on recurrence and survival-analysis of 11,890 cases with more than 25-year follow-up.

A series of 11,890 patients from the senior investigator's surgical service between 1949 and 1998 is analyzed for the significance of distinct risk factors for recurrence of, and survival from, atherosclerotic occlusive disease. Eight risk factors have been assessed for their importance in 4 defined arterial categories (the coronary arterial bed, the branches of the aorta, the abdominal visceral [celiac, superior mesenteric, and renal] arteries, and the terminal abdominal aorta and its major branches) in determining survival rate of the entire group and their impact on rate of recurrence of atherosclerosis in a subgroup of 5,568 patients who had > or =1 postoperative arteriogram, permitting precise identification of changes in the atherosclerotic process. Patients in these 2 groups were followed for > or =25 years; univariate and multivariate analyses were used. On admission all patients had symptomatic atherosclerotic occlusive disease in a single vascular category. Each patient was treated surgically for alleviation of the disease. Two primary outcomes are included: (1) survival, by atherosclerosis category, in all 11,890 patients; and (2) recurrence, also by category, in the subset of 5,568 patients. Multivariate results for recurrence showed little consistency across categories. Only 1 risk factor, diabetes, appeared in 2 of the 3 categories fully analyzed. Other variables that are significant in only a single category are male sex, cholesterol, hypertension, and smoking. Survival showed much greater consistency, with age, diabetes, and hypertension significant in all 3 categories, male sex and smoking in 2, and cholesterol in only Category I. Univariate results followed much the same trend. For recurrence and survival, the response of the arterial bed to the risk factors in each of the 4 categories is distinctly different, an observation that we have not found to be previously reported.

[The DeBakey VAD axial flow pump: first clinical experience with a new generation of implantable, nonpulsatile blood pumps for long-term support prior to transplantation]. / Die DeBakey VAD-Axialpumpe: Erste klinische Erfahrungen mit einer neuen Generation von implantierbaren, nonpulsatilen Blutpumpen als Langzeit-Uberbrückung bis zur Transplantation.

Because of the high frequency of acute hemodynamic deterioration in patients awaiting cardiac transplantation, mechanical techniques of circulatory support to bridge the period until transplantation have become a standard clinical procedure. Continuous-flow rotary blood pumps offer exciting new perspectives in terms of ventricular assistance and/or as a total cardiac substitute. A DeBakey VAD axial flow pump was implanted in two male patients (aged 44 and 65 years, respectively) suffering from end-stage left heart failure. In the initial postoperative period the mean flow rate of the pump was 3.9 +/- 0.5 l/min. In both patients, the early postoperative phase was characterised by a completely non-pulsatile flow profile. Two weeks after implantation and partial recovery of the natural left ventricle, increasing pulse pressures became evident and net flow increased to 4.5 +/- 0.6 l/min. Patients were mobilised and made to under-go regular physical training. Hemolysis produced by the pump was low while free haemoglobin stayed in physiological ranges, increasing only slightly from 2.1 +/- 0.8 mg/dl preoperatively to 3.0 +/- 1.5 mg/dl ten weeks after implantation. One patient was successfully transplanted on day 74 after implantation of the DeBakey VAD while the second patient is, after 110 days of pumping, still waiting for transplantation. This first experience concerning clinical implantation of the DeBakey VAD axial flow pump showed that the device is promising as a means of providing mechanical support to bridge the period until cardiac transplantation.

A miniature implantable axial flow ventricular assist device.

BACKGROUND: Since 1984, in collaboration with NASA engineers, we developed an axial flow pump that is 86 mm long, 22 mm wide, weighs 95 g, produces a flow of 5 to 6 L/min against a 100-mm Hg pressure at about 10,000 rpm, and requires less than 10 W of power. METHODS: The pump has been implanted in 9 calves with the inlet cannula inserted into the left ventricle and the outlet cannula, consisting of an albumin-coated Dacron graft, attached by end-to-side anastomosis to the descending thoracic aorta. RESULTS: All animals showed normal behavior until they were killed 1 to 3 months after operation. At autopsy, systemic studies of vital organs demonstrated no evidence of thromboembolism; the rpm of the pump was maintained between 9,000 and 10,000; the wattage ranged between 7 and 9; the output between 4 and 5 L/min; the hemoglobin was maintained between 32 and 35 mg/dL; the plasma-free hemoglobin ranged between 0.5 and 3 mg/dL; the BUN ranged between 8 and 14 mg/dL; the creatinine remained less than 1 mg/dL; and bilirubin studies were within normal limits. Bearing wear-tear tests up to about 5 months have been negative. CONCLUSIONS: The performance characteristics of the pump implanted in calves up to 90 days are highly gratifying, particularly in terms of pump output of 5 L/min, an index of hemolysis well within normal limits, and absence of thromboembolism.