A model for sustainable short-term international medical trips.

The health status of many people in developing countries is often dismal compared with the norms in industrialized countries. Increasingly, medical practitioners in the United States and other industrialized countries have become interested in global health issues, an interest that often takes the form of short-term international medical trips. We discuss several ethical issues associated with participation in such trips and use our experiences in developing the Children's Health International Medical Project of Seattle (CHIMPS) to outline and illustrate a set of 7 guiding principles for making these trips. CHIMPS is a resident-run, faculty-supported international medical program founded in 2002 by pediatric residents at the University of Washington in Seattle. Members of CHIMPS work with a rural community in El Salvador to support ongoing public health interventions there and provide sustainable medical care in collaboration with the community and a local nongovernmental organization. The 7 principles developed as a result of this work-mission, collaboration, education, service, teamwork, sustainability, and evaluation-can be used as a model for health practitioners as they develop or select international medical trips. The importance of partnering with the community and working within the existing medical and public health infrastructure is emphasized. Many of the challenges of doing international medical work can be overcome when efforts are guided by a few specific principles, such as those we have outlined.     

Reconstruction of mandibular defects with metallic prostheses and microvascular jejunal autografts: an experimental study

A study was undertaken to determine the adequacy of vascularised jejunum to provide stable mucosal cover over a non-biological mandibular substitute. Employing a canine model, composite intra-oral bone-mucosal defects were created and reconstructed with a metal plate covered by a microvascular jejunal patch. These were followed for six months and were assessed clinically, histologically and radiologically. Rapid mucosal healing occurred in all cases. The autografts conformed to the contour of the prosthesis and adequate tongue mobility was preserved. All mandibles remained stable throughout the follow-up period. Histologically, short villi covered the jejunal grafts to three months whilst at six months both normal and abnormal jejunal mucosal morphology was evident.     

Coagulopathy induced by aortoiliac aneurysms

Diffuse intravascular coagulopathy (DIC) or consumptive coagulopathy is infrequently associated with aortic aneurysms. When the two coexist, they create a difficult clinical problem that requires optimal medical and surgical care. Two cases of coagulopathy associated with aortoiliac aneurysm are presented to exemplify the broad clinical picture that can be present. The definitive treatment of DIC is removal of the underlying cause. The following recommendations are made for the management of patients with aortic aneurysms and possible coagulopathy: preoperatively examine the patient for hematomas and ecchymoses; measure levels of fibrinogen, platelets and fibrin degradation products and the prothrombin and partial thromboplastin times; perform arteriography and check puncture sites for spontaneous bleeding afterwards; at aneurysm repair ensure meticulous hemostasis and compensate for excessive blood loss by high-speed autotransfusion.     

The significance of resection length on the patency rate, and the histopathology, of experimentally avulsed and microsurgically repaired blood vessels

The significance of resection length on patency rate, and the histopathology, of microsurgically repaired avulsed blood vessels was examined at 3 weeks in two groups of experimentally avulsed rabbit femoral arteries repaired by different surgeons and in a single series of avulsed and repaired veins. All veins were patent 3 weeks after avulsion and microsurgical repair. Histopathology indicated that the vast majority of lesions in veins were removed at resection. Surgeon A achieved 75% patent arteries and Surgeon B achieved 100% arterial patency (resecting 3.7 mm more on average than Surgeon A). Histopathology revealed numerous luminal circumferential lesions remained in the avulsed artery wall following resection. These lesions were sites of smooth muscle cell proliferation and neointima formation. Although similar arterial damage occurs in human avulsion, considerably lower patency rates are achieved for human arterial avulsion repair than were reported in this experimental study. Factors in addition to vessel wall damage must therefore be involved in thrombosis and occlusion of repaired avulsed arteries. Such factors might be lengthy ischaemia time and severe spasm.     

MRI relaxation fluctuations in acute reperfused hemorrhagic infarction.

MRI evaluations of intramyocardial hemorrhage in acute infarction have relied on T(2) and T(2)(*) shortening only. We propose a more comprehensive evaluation of hemorrhagic infarction based on the concept that fluctuations in T(2) and T(1) relaxation in acute reperfused infarction will reflect transient edema and hemoglobin oxidative denaturation to uncompartmentalized methemoglobin. Anteroapical infarction was created via percutaneous balloon in young swine (22-25 kg, N = 12). T(2), T(1), diastolic wall thickness (DWT), and the Gd-DTPA partition coefficient (lambda) were measured on days 0, 2, and 7. DWT was elevated at 1 hr postreperfusion (128% +/- 53%, P = 0.0001), and alleviated on days 2 and 7 (48% +/- 10%, P = 0.008; 53% +/- 24%, P = 0.003). T(2) and T(1) elevations were coincident with early edema (DeltaT(2) = 55% +/- 24%, P < 0.0001; DeltaT(1) = 27% +/- 18%, P < 0.04). T(2) and T(1) were nearly normal on day 2 (DeltaT(2) = 8% +/- 8%, P = 0.27; DeltaT(1) = 0% +/- 1%, P = 0.65). On day 7, T(2) increased while T(1) decreased (DeltaT(2) = 27% +/- 16%, P = 0.005; DeltaT(1) = -14% +/- 10%, P = 0.02). Lambda was elevated by >150% at all time points (P < or = 0.002). Histology verified hemorrhagic injury. T(1) and T(2) fluctuations are consistent with transient edema, as well as hemoglobin oxidative denaturation to decompartmentalized methemoglobin. This methodological development may broaden our understanding of hemorrhagic microvascular injury and improve its detection in clinical populations.     

The High Mortality of Gastrointestinal Bleeding in HIV-Seropositive Patients: A Multivariate Analysis of Risk Factors and Warning Signs of Mortality in 50 Consecutive Patients

The patterns of which human immunodeficiency virus (HIV)-seropositive patients underwent endoscopy for gastrointestinal bleeding at a university hospital were analyzed in 50 consecutive patients admitted from July 1984 through December 1989, and criteria were developed as to which patients are most likely to benefit from endoscopy. Analyzed patient data included the medical records, follow-up until July 1990 obtained by telephone questionnaire in 46 patients, and autopsy findings in the 11 patients undergoing autopsy. Thirty-seven percent of the patients did not undergo endoscopic or radiographic examinations indicated to determine the cause of bleeding. The adequacy of the evaluation was not related to race, intravenous drug abuse, homosexuality, hemophilia, the diagnosis of known AIDS, or being a public patient. In 21 of the 28 cases in which the cause of bleeding was determined, the diagnosed lesions had a specific, effective therapy. The mortality from gastrointestinal bleeding was 39.0%, compared with 8.3% in 48 controls without known HIV infection (p less than 0.001 by Fisher's exact test, odds ratio = 7.0, odds ratio confidence interval = 5.0-9.7). Statistically significant independent predictors of mortality included leukocytosis, concurrent major diseases, intravenous drug abuse, transfusion of 5 or more units of packed erythrocytes, and the presence of a bloody nasogastric aspirate or hematemesis (Wilk's lambda statistic = 0.369, p less than 0.0001). In particular, 10 of 11 patients (89%) with two or more concurrent major diseases died, whereas only three of 24 patients (13%) with no concurrent diseases died during the hospitalization. We conclude a large percentage of HIV-seropositive patients did not undergo a diagnostic evaluation for gastrointestinal bleeding at a university hospital, and there was no discernible rational pattern as to which patients underwent endoscopy. Endoscopy is an important and indicated procedure in HIV-seropositive patients with no or one concomitant major illness. HIV-seropositive patients with gastrointestinal bleeding and two or more concomitant major illnesses have an exceedingly poor prognosis, and are less likely to benefit from invasive diagnostic tests and aggressive therapy.     

Changes in myocardial echo amplitude during reversible ischaemia in humans.

OBJECTIVE--This study investigated the changes in regional myocardial ultrasonic backscatter, measured as myocardial echo amplitude, that occur during reversible myocardial ischaemia in humans. DESIGN--Left anterior descending coronary angioplasty was used to produce reversible myocardial ischaemia in human subjects. Regional myocardial echo amplitude was studied in the interventricular septum and left ventricular posterior free wall before, during, and after coronary occlusion with the angioplasty balloon. Wall motion analysis of the left ventricle was performed from simultaneous cross sectional echocardiographic imaging. Patients were studied prospectively. PATIENTS--Six patients (mean age 56 (SD 11), range 46 to 69 years) with single vessel, left anterior descending coronary artery stenoses, were investigated during elective coronary angioplasty. A total of 11 balloon inflations were studied. SETTING--All patient studies were performed at Harefield Hospital. Echo amplitude analysis was performed at the Royal Brompton Hospital. INTERVENTIONS--Angioplasty was performed by the usual procedure at Harefield Hospital for elective coronary angioplasty. All routine medication including beta blockers and calcium antagonists were continued. Inflation pressures were up to 12 atm (1212 kPa) and mean inflation time ranged from 30 to 120 (86 (31)) s. In four studies the first inflation was examined, in three the second, in two the third, and in one each the fourth and fifth inflations. Echo amplitude and cross sectional echo-cardiographic studies were recorded with a 3.5 MHz Advanced Technology Laboratories (ATL) (720A/8736 series) mechanical sector scanner and an ATL Mark III (860-1 series) echocardiograph system with 45 dB logarithmic grey scale compression. MAIN OUTCOME MEASURES--Regional echo amplitude was examined in four regions of the left ventricle--namely, the basal and mid-septum, and basal and mid-posterior wall. Consecutive end diastolic and end systolic frames were analysed and cyclic variation was determined as the difference between the level of echo amplitude at end diastole and at end systole. Measurements were made before balloon inflation, at peak inflation, and after balloon deflation. Regional wall motion and systolic wall thickening were analysed qualitatively. RESULTS--Before balloon inflation, cyclic variation in echo amplitude was noted in all regions (basal septum, 2.4 (SD 1.1) dB; mid-septum, 2.5 (1.1) dB; basal posterior wall, 3.3 (2.1) dB; mid-posterior wall, 3.9 (1.6) dB). During balloon inflation there was a significant fall in cyclic variation to 0.4 (0.9) dB (p < 0.0002) in the mid-septum. This was predominantly owing to an increase in end systolic echo amplitude from 5.4 (2.0) dB to 9.3 (1.9) dB (p < or = 0.01). This was associated with the development of severe hypokinesis or akinesis in the mid-septum. No significant changes in echo amplitude occurred in the three other regions examined. Changes were completely reversed after balloon deflation. CONCLUSIONS--These results suggest a causal relation between occlusion of the supplying coronary artery and blunting of myocardial echo amplitude cyclic variation. It is suggested that balloon occlusion produced myocardial ischaemia. The resultant impairment of myocardial contraction then caused a blunting of cyclic variation in echo amplitude. The results of this study provide further data about the ability of quantitative studies of ultrasonic backscatter to identify alterations in the myocardium during injury.