Biomedical subjects

L Chan

Publications and source records attributed to L Chan.

At least 37 records · Page 2Linked to original sources

PubMed2001

Reliable variables in the exsanguinated patient which indicate damage control and predict outcome.

BACKGROUND: Exsanguination as a syndrome is ill defined. The objectives of this study were to investigate the relationship between survival and patient characteristics--vital signs, factors relating to injury and treatment; determine if threshold levels of pH, temperature, and highest estimated blood loss can predict survival; and identify predictive factors for survival and to initiate damage control. MATERIAL AND METHODS: A retrospective 6-year study was conducted, 1993 to 1998. In all, 548 patients met one or more criteria: (1) estimated blood loss > or =2,000 mL during trauma operation; (2) required > or =1,500 mL packed red blood cells (PRBC) during resuscitation; or (3) diagnosis of exsanguination. Analysis was made in two phases: (1) death versus survival in emergency department (ED); (2) death versus survival in operating room (OR). Statistical methods were Fisher's exact test, Student's t test, and logistic regression. RESULTS: For 548 patients, mean Revised Trauma Score 4.38, mean Injury Severity Score 32. Penetrating injuries 82% versus blunt injuries 18%. Vital statistics in emergency department: mean blood pressure 63 mm Hg, heart rate 78 beats per minute. Mean OR pH 7.15 and temperature 34.3 degrees C. Mortality was 379 of 548 (69%). Predictive factors for mortality (means): pH < or =7.2, temperature <34 degrees C, OR blood replacement >4,000 mL, total OR fluid replacement >10,000 mL, estimated blood loss >15 mL/minute (P <0.001). Analysis 1: death versus survival in ED, logistic regression. Independent risk factors for survival: penetrating trauma, spontaneous ventilation, and no ED thoracotomy (P <0.001; probability of survival 0.99613). Analysis 2: death versus survival in OR, logistic regression. Independent risk factors for survival: ISS < or =20, spontaneous ventilation in ED, OR PRBC replacement <4,000 mL, no ED or OR thoracotomy, absence of abdominal vascular injury (P <0.001, max R(2) 0.55, concordance 89%). CONCLUSIONS: Survival rates can be predicted in exsanguinating patients. "Damage control" should be performed using these criteria. Knowledge of these patterns can be valuable in treatment selection.

Adolescent↗

PubMed2001

TRISS methodology: an inappropriate tool for comparing outcomes between trauma centers.

BACKGROUND: The TRISS methodology has been used for comparison of survival outcomes between trauma centers. The purpose of this study was to evaluate the role of TRISS in comparing outcomes between a small and a large trauma center and evaluate its usefulness in various groups of patients. STUDY DESIGN: Trauma registry study that compared the survival outcomes between a large academic level I trauma center and a small community level II center. The comparison was made with the standard TRISS probability of survival, M value, and Z score. In the second part of the study the patients from the small center were matched for age, gender, injury severity score, Glasgow Coma Scale, head Abbreviated Injury Score, BP, prehospital respiratory assistance, and transport mode with an equal number of patients from the large center. The Z scores were calculated for each center. In the third part of the study the TRISS usefulness and limitations were evaluated in various subgroups of patients by calculating its sensitivity, specificity, positive predictive value, negative predictive value, and misclassification rate. RESULTS: The Z value of the large center (3,315 patients) was 2.24, indicating a considerably higher mortality than expected when compared with the Major Trauma Outcomes Study population. The Z value of the small center (331 patients) was -0.92, indicating fewer than the Major Trauma Outcomes Study expected deaths. In the second part of the study, 297 patients from the small center were matched with an equal number from the large center. The Z scores were -0.40 and -0.95, respectively, indicating slightly better outcomes than those of the Major Trauma Outcomes Study. Additional evaluation of the TRISS prediction of survival in various subgroups of patients showed a high misclassification rate in severe trauma, in some groups higher than 25%. CONCLUSIONS: The TRISS methodology is not a reliable tool for comparing outcomes between trauma centers and has an unacceptably high misclassification rate in patients with severe trauma.

Benchmarking↗

PubMed2001

Multiinstitutional experience with the management of superior mesenteric artery injuries.

BACKGROUND: Superior mesenteric artery (SMA) injuries are rare and often lethal injuries incurring very high morbidity and mortality. The purposes of this study are to review a multiinstitutional experience with these injuries; to analyze Fullen's classification based on anatomic zone and ischemia grade for its predictive value; to correlate the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) for abdominal vascular injury with mortality; and to identify independent risk factors predictive of mortality, describing current trends for the management of this injury in America. DESIGN: We performed a retrospective multiinstitutional study of patients sustaining SMA injuries involving 34 trauma centers in the US over 10 years. Outcomes variables, both continuous and dichotomous, were analyzed initially with univariate methods. For the subsequent multivariate analysis, stepwise logistic regression was used to identify a set of risk factors significantly associated with mortality. RESULTS: There were 250 patients enrolled, with a mean Revised Trauma Score (RTS) of 6.44 and a mean Injury Severity Score (ISS) of 25. Surgical management consisted of ligation in 175 of 244 patients (72%), primary [corrected] repair in 53 of 244 patients (22%), autogenous grafts were used in 10 of 244 (4%), and prosthetic grafts of PTFE in 6 of 244 patients (2%). Overall mortality was 97 of 250 patients (39%). Mortality versus Fullen's zones: zone I, 39 of 51 (76.5%); zone II, 15 of 34 (44.1%); zone III, 11 of 40 (27.5%); and zone IV, 25 of 108 (23.1%). Mortality versus Fullen's ischemia grade: grade 1, 22 of 34 (64.7%). Mortality versus AAST-OIS for abdominal vascular injury: grade I, 9 of 55 (16.4%); grade II, 13 of 51 (25.5%); grade III, 8 of 20 (40%); grade IV, 37 of 69 (53.6%); and grade V, 17 of 19 (89.5%). Logistic regression analysis identified as independent risk factors for mortality the following: transfusion of greater than 10 units of packed RBCs, intraoperative acidosis, dysrhythmias, injury to Fullen's zone I or II, and multisystem organ failure. CONCLUSION: SMA injuries are highly lethal. Fullen's anatomic zones, ischemia grade, and AAST-OIS abdominal vascular injuries correlate well with mortality. Injuries to Fullen's zones I and II, Fullen's maximal ischemia grade, and AAST-OIS injury grades IV and V, high-intraoperative transfusion requirements, and presence of acidosis and disrhythmias are significant predictors of mortality. All of these predictive factors for mortality must be taken into account in the surgical management of these injuries.

Adolescent↗

PubMed2001

Evolution of immunosuppression and continued importance of acute rejection in renal transplantation.

As steady improvement in short-term kidney graft survival and long-term outcomes prolongs the lives of transplant patients, responsibility for their care is shifting away from transplant specialists and into the hands of community nephrologists. Therefore, community nephrologists need to have a deeper understanding of immunosuppressive therapies than ever before. Pharmacologic immunosuppression has been continuously evolving over the past two decades. Azathioprine was introduced in the early 1960s. Introduction of cyclosporine (CsA) in 1983 revolutionized short-term outcomes after renal transplantation. The first monoclonal antibody immunosuppressant, OKT3, was introduced in 1986. The 1990s saw the introduction of a number of important new agents, including mycophenolate mofetil (MMF), tacrolimus, and a microemulsion CsA, as well as two new monoclonal antibodies. Combinations of these new agents, along with improving clinical care, have produced 1-year patient survival approaching 100% and graft survival exceeding 90%. The newest class of agents, the first of which is sirolimus, is called target of rapamycin (TOR) inhibitors and is used with CsA for maintenance therapy. Immunosuppressive drug therapy after kidney transplantation continues to evolve. There is a variety of pharmacologic combinations from which to choose, based on immunologic risk and side effect profiles. As new regimens are developed, ongoing communications between the transplant center and community nephrologists will be required to implement therapeutic changes and optimize patient care successfully.

Graft Rejection↗

PubMed2001

Discharge disposition from acute care after traumatic brain injury: the effect of insurance type.

OBJECTIVE: To determine if persons with traumatic brain injury (TBI) who are insured by Medicaid or health maintenance organizations (HMOs) are more likely to receive postacute care in skilled nursing facilities (SNFs) than in rehabilitation facilities, compared with persons insured by commercial fee-for-service (FFS) plans. DESIGN: Retrospective cohort study. SETTING: County hospital admitting 30% of all Washington State TBI patients. PATIENTS: Patients with moderate to severe TBI discharged to rehabilitation facilities or SNFs between 1992 and 1997 (n = 1271); 56.3% were insured by Medicaid, 26.1% by FFS plans, and 17.6% by HMOs. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Disposition on discharge from acute care (rehabilitation facilities vs SNF); adjusted relative risk (RR) and confidence interval (CI) for different insurance types. RESULTS: After accounting for confounding factors, Medicaid patients were 68% more likely (RR = 1.68, 95% CI = 1.34-2.11) and HMO patients were 23% more likely (RR = 1.23, 95% CI =.90-1.68) to go to a SNF than FFS patients. However, the latter difference was not statistically significant. CONCLUSIONS: An association exists between insurance type and postacute care site. Efforts should be made to determine the effect this relationship has on the cost and outcomes for TBI patients.

Abbreviated Injury Scale↗

PubMed2001

Using medicare databases for outcomes research in rehabilitation medicine.

With the advent of computerized billing for healthcare services, claims data have become useful in academic medicine. One of the largest suppliers of these types of data is Medicare, the US Government's healthcare insurance organization for the elderly and disabled. Because Medicare patients often require rehabilitation, this type of data can be useful in rehabilitation outcomes studies. Despite several significant limitations to Medicare billing data, Medicare claims data are powerful tools with which to analyze concepts in physical medicine and rehabilitation.

Aged↗

PubMed2001

Resident research education in physical medicine and rehabilitation: a practical approach.

The Accreditation Council for Graduate Medical Education includes training in research as a required component of physical medicine and rehabilitation residency programs. Unfortunately, there is a lack of practical information on how to meet this requirement. In this paper, information is provided for individuals involved in resident education on how to teach residents about research.

Curriculum↗

PubMed2001

Clinically significant blunt cardiac trauma: role of serum troponin levels combined with electrocardiographic findings.

BACKGROUND: The true importance of blunt cardiac trauma (BCT) is related to the cardiac complications arising from it. Diagnostic tests that can predict accurately if such complications will develop or not may allow early and aggressive monitoring or early discharge. We investigated the role of two simple and convenient tests, serum cardiac troponin I (cTnI) and electrocardiogram (ECG), when used to identify patients at risk of cardiac complications after BCT. METHODS: Over a 10-month period, 115 patients with evidence of significant blunt thoracic trauma were prospectively followed to identify the presence of clinically significant BCT (Sig-BCT), defined as cardiogenic shock, arrhythmias requiring treatment, or structural cardiac abnormalities directly related to the cardiac trauma. An ECG was obtained at admission and at 8 hours. Cardiac troponin I was measured at admission, at 4 hours, and at 8 hours. Transthoracic echocardiography was performed when clinically indicated. The sensitivity, specificity, and positive and negative predictive values of ECG and cTnI to identify Sig-BCT were calculated. Clinical risk factors for Sig-BCT were examined by univariate and multivariate analysis. RESULTS: Nineteen patients (16.5%) were diagnosed with Sig-BCT and, in 18 of them, symptoms presented within 24 hours of admission. Abnormal electrocardiographic findings were detected in 58 patients (50%) and elevated cTnI levels in 27 (23.5%). Electrocardiography and cTnI had positive predictive values of 28% and 48% and negative predictive values of 95% and 93%, respectively. However, when both tests were abnormal (positive) or normal (negative), the positive and negative predictive values increased to 62% and 100%, respectively. Other independent risk factors for Sig-BCT were head injury, spinal injury, history of preexisting cardiac disease, and a chest Abbreviated Injury Score greater than 2. CONCLUSION: The combination of ECG and cTnI identifies reliably the presence or absence of Sig-BCT. Patients with an abnormal ECG and cTnI need close monitoring for at least 24 hours. Patients with a normal admission ECG and cTnI can be safely discharged in the absence of other injuries.

Electrocardiography↗

PubMed2001

Penetrating esophageal injuries: multicenter study of the American Association for the Surgery of Trauma.

OBJECTIVE: The purpose of this study was to define the period of time after which delays in management incurred by investigations cause increased morbidity and mortality. The outcome study is intended to correlate time with death from esophageal causes, overall complications, esophageal related complications, and surgical intensive care unit length of stay. METHODS: This was a retrospective multicenter study involving 34 trauma centers in the United States, under the auspices of the American Association for the Surgery of Trauma Multi-institutional Trials Committee over a span of 10.5 years. Patients surviving to reach the operating room (OR) were divided into two groups: those that underwent diagnostic studies to identify their injuries (preoperative evaluation group) and those that went immediately to the OR (no preoperative evaluation group). Statistical methods included Fisher's exact test, Student's T test, and logistic regression analysis. RESULTS: The study involved 405 patients: 355 male patients (86.5%) and 50 female patients (13.5%). The mean Revised Trauma Score was 6.3, the mean Injury Severity Score was 28, and the mean time interval to the OR was 6.5 hours. There were associated injuries in 356 patients (88%), and an overall complication rate of 53.5%. Overall mortality was 78 of 405 (19%). Three hundred forty-six patients survived to reach the OR: 171 in the preoperative evaluation group and 175 in the no preoperative evaluation group. No statistically significant differences were noted in the two groups in the following parameters: number of patients, age, Injury Severity Score, admission blood pressure, anatomic location of injury (cervical or thoracic), surgical management (primary repair, resection and anastomosis, resection and diversion, flaps), number of associated injuries, and mortality. Average length of time to the OR was 13 hours in the preoperative evaluation group versus 1 hour in the no preoperative evaluation group (p < 0.001). Overall complications occurred in 134 in the preoperative evaluation group versus 87 in the no preoperative evaluation group (p < 0.001), and 74 (41%) esophageal related complications occurred in the preoperative evaluation group versus 32 (19%) in the no preoperative evaluation group (p = 0.003). Mean surgical intensive care unit length of stay was 11 days in the preoperative evaluation group versus 7 days in the no preoperative evaluation group (p = 0.012). Logistic regression analysis identified as independent risk factors for the development of esophageal related complications included time delays in preoperative evaluation (odds ratio, 3.13), American Association for the Surgery of Trauma Organ Injury Scale grade >2 (odds ratio, 2.62), and resection and diversion (odds ratio, 4.47). CONCLUSION: Esophageal injuries carry a high morbidity and mortality. Increased esophageal related morbidity occurs with the diagnostic workup and its inherent delay in operative repair of these injuries. For centers practicing selective management of penetrating neck injuries and transmediastinal gunshot wounds, rapid diagnosis and definitive repair should be made a high priority.

Adolescent↗

PubMed2001

Penetrating colon injuries requiring resection: diversion or primary anastomosis? An AAST prospective multicenter study.

BACKGROUND: The management of colon injuries that require resection is an unresolved issue because the existing practices are derived mainly from class III evidence. Because of the inability of any single trauma center to accumulate enough cases for meaningful statistical analysis, a multicenter prospective study was performed to compare primary anastomosis with diversion and identify the risk factors for colon-related abdominal complications. METHODS: This was a prospective study from 19 trauma centers and included patients with colon resection because of penetrating trauma, who survived at least 72 hours. Multivariate logistic regression analysis was used to compare outcomes in patients with primary anastomosis or diversion and identify independent risk factors for the development of abdominal complications. RESULTS: Two hundred ninety-seven patients fulfilled the criteria for inclusion and analysis. Overall, 197 patients (66.3%) were managed by primary anastomosis and 100 (33.7%) by diversion. The overall colon-related mortality was 1.3% (four deaths in the diversion group, no deaths in the primary anastomosis group, p = 0.012). Colon-related abdominal complications occurred in 24% of all patients (primary repair, 22%; diversion, 27%; p = 0.373). Multivariate analysis including all potential risk factors with p values < 0.2 identified three independent risk factors for abdominal complications: severe fecal contamination, transfusion of > or = 4 units of blood within the first 24 hours, and single-agent antibiotic prophylaxis. The type of colon management was not found to be a risk factor. Comparison of primary anastomosis with diversion using multivariate analysis adjusting for the above three identified risk factors or the risk factors previously described in the literature (shock at admission, delay > 6 hours to operating room, penetrating abdominal trauma index > 25, severe fecal contamination, and transfusion of > 6 units blood) showed no statistically significant difference in outcome. Similarly, multivariate analysis and comparison of the two methods of colon management in high-risk patients showed no difference in outcome. CONCLUSION: The surgical method of colon management after resection for penetrating trauma does not affect the incidence of abdominal complications, irrespective of associated risk factors. Severe fecal contamination, transfusion of > or = 4 units of blood within the first 24 hours, and single-agent antibiotic prophylaxis are independent risk factors for abdominal complications. In view of these findings, the reduced quality of life, and the need for a subsequent operation in colostomy patients, primary anastomosis should be considered in all such patients.

Adult↗

PubMed2001

Type and crossmatch of the trauma patient.

OBJECTIVE: To identify a population of trauma patients in the emergency department (ED) that do not require emergent blood transfusion via a combination of clinical risk factors that are readily accessible and easily obtained. METHOD: A review of trauma patients was conducted for a 6-month period. Crossmatched patients were identified and examined for clinical characteristics and whether transfusion was performed. Risk factors for transfusion were identified and a model was developed for predicting likelihood of transfusion. RESULTS: Six hundred fifty-four patients were crossmatched, with emergent transfusion occurring in 81 (12.4%). Four risk factors were identified: systolic blood pressure < 90 mm Hg, Glasgow Coma Scale score < 9, pulse > 120 beats/min, and high-risk injury (trauma to the chest between the midclavicular lines, abdominal injury with diffuse tenderness, survival of a fatal vehicular crash, ejection from a vehicle, or stab or gunshot wound to the trunk). Patients with no risk factors were shown to have a 2.2% incidence of transfusion with no emergent transfusions occurring in the ED. CONCLUSION: Trauma patients with no risk factors at presentation were less likely to require emergent blood transfusion, especially in the setting of the ED.

Blood Grouping and Crossmatching↗

PubMed2001

Oral tolerance to protein antigens.

Oral tolerance is an active non-response to antigens delivered via the oral route. Mechanisms governing tolerance induction have been well characterized in mouse. Similar studies in man are lacking, although there is evidence that tolerance can be induced. In disease states, tolerance is altered and this may account for the presence of mucosal inflammation. In food hypersensitivity there is evidence that allergens may be handled differently and this may play a role in disease expression.

Administration, Oral↗

PubMed2001

Emergency medicine terminology in the United Kingdom--time to follow the trend?

OBJECTIVE: To determine the frequency of use of the terms "accident and emergency" and "emergency medicine" and their derivatives in original articles in the Journal of Accident and Emergency Medicine. METHODS: Hand search of all articles in the Journal of Accident and Emergency Medicine from September 1995 to July 2000, categorising the first use of terminology in each original article to describe the specialty, its departments, or their staff into either accident and emergency or emergency medicine groups. RESULTS: There is a clear trend towards increasing use of the terms emergency medicine, emergency physician and emergency department, with decreasing use of the terms accident and emergency medicine, accident and emergency department and accident and emergency doctor, although the latter group still constitutes the majority. CONCLUSION: The use of emergency medicine to describe the specialty in the United Kingdom is increasing, although this may reflect the Journal's growing international standing. This trend should be taken into account in the debate over the specialty's name in this country.

Accidents↗

PubMed2001

Outcome prediction of emergency patients by noninvasive hemodynamic monitoring.

OBJECTIVES: We used noninvasive hemodynamic monitoring in the initial resuscitation beginning in the emergency department (ED) for the following reasons: (1) to describe early survivor and nonsurvivor patterns of emergency patients in terms of cardiac, pulmonary, and tissue perfusion deficiencies; (2) to measure quantitatively the net cumulative amount of deficit or excess of the monitored functions that correlate with survival or death; and (3) to explore the use of discriminant analysis to predict outcome and evaluate the biological significance of monitored deficits. METHODS: This is a descriptive study of the feasibility of noninvasive monitoring of patients with acute emergency conditions in the ED to evaluate and quantify hemodynamic deficits as early as possible. The noninvasive monitoring systems consisted of a bioimpedance method for estimating cardiac output together with pulse oximetry to reflect pulmonary function, transcutaneous oxygen tension to reflect tissue perfusion, and BP to reflect the overall circulatory status. These continuously monitored noninvasive measurements were used to prospectively evaluate circulatory patterns in 151 consecutively monitored severely injured patients beginning with admission to the ED in a university-run county hospital. The net cumulative deficit or excess of each monitored parameter was calculated as the cumulative difference from the normal value vs the time-integrated monitored curve for each patient. The deficits of cardiac, pulmonary, and tissue perfusion functions were analyzed in relation to outcome by discriminant analysis and were cross-validated. RESULTS: The mean (+/- SEM) net cumulative excesses (+) or deficits (-) from normal in surviving vs nonsurviving patients, respectively, were as follows: cardiac index (CI), +81 +/- 52 vs -232 +/- 138 L/m(2) (p = 0.037); arterial hemoglobin saturation, -1 +/- 0.3 vs -8 +/- 2.6%/h (p = 0.006); and tissue perfusion, +313 +/- 88 vs -793 +/- 175, mm Hg/h (p = 0.001). The cumulative mean arterial BP deficit for survivors was -10 +/- 13 mm Hg/h, and for nonsurvivors it was -57 +/- 24 mm Hg/h (p = 0.078). CONCLUSIONS: Noninvasive monitoring systems provided continuously monitored on-line displays of data in the early postadmission period from the ED to the operating room and to the ICU for early recognition of circulatory dysfunction in short-term emergency conditions. Survival was predicted by discriminant analysis models based on the quantitative assessment of the net cumulative deficits of CI, arterial hypoxemia, and tissue perfusion, which were significantly greater in the nonsurvivors.

Adult↗

PubMed2001

The role of gynecologists in providing primary care to elderly women.

BACKGROUND: Federal legislation has recently been proposed to designate obstetrician-gynecologists (OBGs) as primary care physicians. The Institute of Medicine identifies care unrestricted by problem or organ system as an essential characteristic of primary care. We examined the degree to which OBGs in the state of Washington offer this aspect of primary care to their elderly patients by investigating the type and amount of nongynecologic care they provide. METHODS: Using 1994 Part B Medicare claims data for Washington residents, we identified visits made by women aged 65 years and older to OBGs (N=10,522) and 9 other types of specialists. Diagnoses were classified as in or out of the domain of care traditionally provided by each specialty. Visit volumes, proportion of out of domain visits, and the frequency of diagnoses were reported. RESULTS: Of the patient visits to obstetrician-gynecologists, 12.2% had nongynecologic diagnoses. The median percentage of nongynecologic visits for individual OBGs was 6.7%. Patients who saw OBGs received 15.4% of their overall health care from an OBG; patients who saw family physicians received 42.9% of their total health care from a family physician. CONCLUSIONS: In 1994, a small amount of the care that Washington OBGs provided to their elderly patients was for nongynecologic conditions. Studies are needed to evaluate how the practices of OBGs have changed since the 1996 implementation of a primary care requirement in obstetrics-gynecology residencies, and if adopted, how legislation designating OBGs as primary care physicians affects the health care received by elderly women.

Age Factors↗

PubMed2001

Hepatitis C virus infection and morphologic study in B lymphocytes of patient with hepatitis C.

OBJECTIVE: To study hepatitis C virus (HCV) infection in B lymphocytes of patients with hepatitis C and to establish a B cell line with HCV infection and observe the hepatitis C virus like particles. METHODS: A B lymphoblastoid cell line was established by Epstein-Barr virus induced transformation directly from peripheral blood mononuclear cells of a patient with hepatitis C. The HCV antigen and HCV RNA were detected by immunohistochemical technique. Reverse transcription-polymerase chain reaction(RT-PCR) and in situ hybridization and HCV particle were detected by electron microscopy. RESULTS: Positive HCV RNA was found in supernatants of B cell line. HCV Ag and HCV RNA were also showed positive. Electron microscopy observed HCV spherical virus like particles with a diameter of approximately 65 nm and 110 nm and the "bud mutation" of HCV in the cytoplasmic vesicles of B lymphocytes. CONCLUSIONS: HCV could infect B lymphocytes and replicate in the cell line. HCV particles are formed by "bud mutation" of HCV in the cytoplasmic vesicles of B-lymphocytes.

B-Lymphocytes↗

PubMed2001

[A study on city motor vehicle emission factors by tunnel test].

Applying the principle of tunnel test to run a typical across-river tunnel test in Guangzhou city, 48 h-online-monitor data include pollutant concentration, traffic activity and meteorological data were gained. The average motor vehicle emission factors of NOx, CO, SO2, PM10 and HC were calculated using mass balance which are 1.379, 15.404, 0.142, 0.637, 1.857 g/km. vehicle respectively. Based on that, combined emission factors of 8 types of city vehicles were calculated using linear regression. The result basically showed the character and level of motor vehicle emission in Chinese city.

Vehicle Emissions↗

PubMed2001

Improving the quality of outpatient care for older patients with diabetes: lessons from a comparison of rural and urban communities.

OBJECTIVE: Our goal was to compare the quality of diabetic care received by patients in rural and urban communities. STUDY DESIGN: We performed a retrospective analysis of claims data captured by the Medicare program. POPULATION: We included all fee-for-service Medicare patients 65 years and older living in the state of Washington who had 2 or more physician encounters for diabetes care during 1994. OUTCOME MEASURES: The outcomes were the extent to which patients received 3 specific recommended services: glycated hemoglobin determination, cholesterol measurement, and eye examination. RESULTS: A total of 30,589 Medicare patients (8.4%) were considered to have diabetes; 29.1% lived in rural communities. Generalists provided most diabetic care in all locations. Patients living in small rural towns received almost half their outpatient care in larger communities. Patients living in large rural towns remote from metropolitan areas were more likely to have received the recommended tests than patients in all other groups. Patients who saw an endocrinologist at least once during the year were more likely to have received the recommended tests. CONCLUSIONS: Large rural towns may provide the best conditions for high-quality care: They are vibrant, rapidly growing communities that serve as regional referral centers and have an adequate-but not excessive-supply of both generalist and specialist physicians. Generalists provide most diabetic care in all settings, and consultation with an endocrinologist may improve adherence to guidelines.

Aged↗