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Yuchiao Chang

Publications and source records attributed to Yuchiao Chang.

At least 37 records · Page 2Linked to original sources
PubMed2005

Rapid absorption of tumescent lidocaine above the clavicles: a prospective clinical study.

BACKGROUND: Tumescent local anesthesia has been adapted for surgery of the face and neck, but there are no data regarding drug absorption when tumescent injection is used in this region. The aim of this study was to characterize the changes in plasma lidocaine concentrations over time when a tumescent solution is injected into the subcutaneous tissue of the neck. The study was carried out in human volunteer subjects, and injection of lidocaine to the thighs provided control data. METHODS: Eight healthy female volunteer subjects were studied twice using a prospective, crossover design. Tumescent lidocaine solution was injected into the subcutaneous tissue of the neck in one session and the thighs in another session. The order of injection was randomized. Blood samples were collected for 14 hours after injection, and the plasma concentration of lidocaine measured. The injected solution consisted of lidocaine 0.1%, NaHCO3 12.5 mEq/L, and epinephrine 1:1,000,000 in normal saline. A standardized dose of lidocaine (7 mg/kg) was used for each injection and no surgical procedure was performed. RESULTS: All subjects completed the study. Subject weight was 66.1 +/- 12.8 kg, body fat was 29.0 +/- 4.7 percent, and body mass index was 23.8 +/- 3.1 kg/m2. The average time to reach peak lidocaine concentration after neck injection was 5.8 hours, whereas peak lidocaine concentration after thigh injection did not occur until 12.0 hours. This difference of 6.2 hours was highly significant (p = 0.009). The average peak concentration after neck injection was 16 percent greater than that after thigh injection (0.94 microg/ml versus 0.81 microg/ml), with the difference approaching significance (p = 0.06). No adverse reactions were noted. CONCLUSIONS: Tumescent injection above the clavicles results in a rapid rise in plasma lidocaine concentration when compared with injection to the lower extremities. Toxic symptoms could occur much earlier than expected for lower extremity tumescent anesthesia. In addition, dangerous plasma levels could occur if tumescent anesthesia in the lower extremities is followed by tumescent injection above the clavicles, because the absorption curves would be superimposed.

Absorption↗
PubMed2005

The effect of surgical and nonsurgical treatment on longitudinal outcomes of lumbar spinal stenosis over 10 years.

OBJECTIVES: To assess the relative effect of initial surgical and nonsurgical treatment on longitudinal outcomes of patients with lumbar spinal stenosis over a 10-year follow-up period. DESIGN: A prospective observational cohort study. SETTING: Enrollment from community-based specialist practices throughout Maine. PARTICIPANTS: One hundred forty-four patients with lumbar spinal stenosis who had at least one follow-up: 77 initially treated surgically and 67 initially treated nonsurgically. INTERVENTION: Initial surgical or nonsurgical treatment. MEASUREMENTS: Clinical data were obtained at baseline and outcomes followed at regular intervals over 10 years with mailed questionnaires including patient-reported symptoms of back pain, leg symptoms, back-specific functional status, and satisfaction. Longitudinal data were analyzed using general linear mixed models. In addition to treatment (initial surgical or nonsurgical care), time period, and the interaction between treatment and time, the models included baseline score, patient age and sex, and a time-varying general health status score. The effects of these covariates in explaining differences between treatment groups were also examined. The effect of subsequent surgical procedures was assessed using different analysis strategies. RESULTS: The 10-year rate of subsequent surgical procedures was 23% and 38% for patients initially treated surgically and nonsurgically, respectively, and the overall 10-year survival rate was 69%. Patients undergoing initial surgical treatment had worse baseline symptoms and functional status than those initially treated nonsurgically. For all outcomes and at each time point, surgically treated patients reported greater improvement in symptoms and functional status and higher satisfaction scores, indicative of better outcomes, than nonsurgically treated patients. However, the relative magnitude of the benefit diminished over time such that the relative differences for low back pain and satisfaction were no longer significant over long-term follow-up (both P=.08 for treatment effect between 5 and 10 years after controlling for covariates). Regardless of initial treatment received, patients undergoing subsequent surgical procedures reported less improvement in outcomes over time than patients who did not undergo subsequent procedures, but the relative differences between treatment groups were similar in analyses that controlled for outcomes after subsequent procedures. CONCLUSION: After controlling for covariates, patients initially treated surgically demonstrated better outcomes on all measures than those initially treated nonsurgically. Although outcomes of initial surgical treatment remained superior over time, the relative benefit of surgery diminished in later years, especially for low back pain and satisfaction. Patients undergoing subsequent surgery had worse outcomes regardless of initial treatment received, but excluding them did not change overall treatment group comparisons. The analytical methods described may be helpful in the design and analysis of future studies comparing treatment outcomes for patients with lumbar spinal stenosis.

Aged↗
PubMed2005

Disagreement between formal and medical record criteria for the diagnosis of acute coronary syndrome.

OBJECTIVES: To measure agreement between formal and medical record criteria for the diagnosis of acute coronary syndrome (ACS) among patients undergoing an emergency department evaluation for potential acute coronary symptoms. METHODS: Cases of ACS were determined by both formal (World Health Organization 1984 criteria for acute myocardial infarction [AMI], Braunwald criteria for unstable angina pectoris [UAP]) and medical record criteria. In the latter, a diagnosis was made if providers indicated AMI or UAP anywhere in the medical record. All information included in formal criteria was available to clinicians establishing the medical record diagnosis. The two criteria for diagnosis were compared, and a kappa value was recorded. Two blinded observers adjudicated discordant cases, with a kappa value recorded. Disagreements between these two coinvestigators were resolved by a Delphi technique. RESULTS: A total of 375 eligible subjects were enrolled, of whom 65 (17%; 45 AMI, 20 UAP) had ACS by both sets of criteria. Formal and medical record criteria disagreed in 32 subjects. This represented 9% (95% confidence interval = 6% to 12%) of the overall study population but 33% (95% confidence interval = 23% to 43%) of subjects with possible ACS. Coinvestigators acting as judges and blinded to each other's determinations agreed that 25 of these subjects had ACS and three did not; they disagreed on four subjects (kappa = 0.54). Among these four subjects, a Delphi consensus technique determined that two subjects had AMI and two had no ACS. CONCLUSIONS: In a single-site study, among subjects who have possible ACS as determined by either or both formal and medical record criteria, these two sets of criteria disagree in almost one third of cases. Among discordant cases, even two expert judges frequently disagreed on the final diagnosis. A modified Delphi technique to address these disagreements is described.

Acute Disease↗
PubMed2005

The accuracy and completeness of data collected by prospective and retrospective methods.

OBJECTIVES: To describe and test a model that compares the accuracy of data gathered prospectively versus retrospectively among adult emergency department patients admitted with chest pain. METHODS: The authors developed a model of information flow from subject to medical record to the clinical study case report form, based on a literature review. To test this model, a bidirectional (prospective and retrospective) study was conducted, enrolling all eligible adult patients who were admitted with a chief complaint of chest pain. The authors interviewed patients in the emergency department to determine their chest pain history and established a prospective database; this was considered the criterion standard. Then, patient medical records were reviewed to determine the accuracy and completeness of the information available through a retrospective medical record review. RESULTS: The model described applies the concepts of reliability and validity to information passed on by the study subject, the clinician, and the medical record abstractor. This study was comprised of 104 subjects, of which 63% were men and the median age was 63 years. Subjects were uncertain of responses for 0-8% of questions and responded differently upon reinterview for subsets of questions 0-30% of the time. The sensitivity of the medical record for risk factors for coronary artery disease was 0.77 to 0.93. Among the 88 subjects (85%) who indicated that their chest pain was substernal or left chest, the medical record described this location in 44%. Timing of the chest pain was the most difficult item to accurately capture from the medical record. CONCLUSIONS: Information obtained retrospectively from the abstraction of medical records is measurably less accurate than information obtained prospectively from research subjects. For certain items, more than half of the information is not available. This loss of information is related to the data types included in the study and by the assumptions that a researcher performing a retrospective study makes about implied versus explicitly stated responses. A model of information flow that incorporates the concepts of reliability and validity can be used to measure some of the loss of information that occurs at each step along the way from subject to clinician to medical record abstractor.

Adult↗
PubMed2005

Superficial neurofibroma: a lesion with unique MRI characteristics in patients with neurofibromatosis type 1.

OBJECTIVE: Our aim was to test the hypothesis that in neurofibromatosis type 1 (NF1), superficial plexiform neurofibromas have different MRI characteristics than deep plexiform neurofibromas. SUBJECTS AND METHODS: Sixty-six patients (median age, 15 years) with superficial plexiform neurofibromas were compared with 56 patients with deep plexiform neurofibromas (median age, 12 years). All patients underwent axial STIR and coronal or sagittal STIR images. RESULTS: Superficial neurofibromas were more likely to be asymmetric (p = 0.004) and extend to the skin surface (p < 0.001). Lesion borders were poorly defined with similar frequency in both superficial and deep groups (77% vs 68%, p = 0.31). The morphology of superficial neurofibromas was more likely diffuse (64% vs 11%, p < 0.001), whereas deep neurofibromas were more likely nodular or fascicular. Of neurofibromas that were nodular or fascicular in morphology, superficial lesions had a smaller maximal fascicle-nodule diameter (mean, 10.3 mm) than deep lesions (mean, 13.4 mm) (p = 0.013). Signal characteristics of deep neurofibromas were more likely to be targetlike (75%) compared with superficial neurofibromas (21%) (p < 0.001). Superficial neurofibromas had a smaller mean volume than deep neurofibromas (180 vs 444 cm(3), p = 0.002). CONCLUSION: Unlike the typical targetlike lesions along the course of major nerves seen in deep plexiform lesions, superficial plexiform neurofibromas in NF1 tend to be asymmetric, have nontargetlike signal intensity, lack nodular or fascicular morphology, and are likely to involve skin.

Adolescent↗
PubMed2005

Peri-procedural protocols for interventional pain management techniques: a survey of US pain centers.

BACKGROUND: Interventional techniques are now an integral part of chronic pain management. As new procedures are arising at a rapid pace, decisions regarding patient safety and comfort are becoming more challenging. No peri-procedural consensus protocol currently addresses issues such as 1. nulla per os (NPO) status, 2. sedation, 3. monitoring, or 4. recovery. In establishing safety guidelines for interventional pain procedures, the knowledge of current peri-procedural protocols is required. OBJECTIVE: To survey interventional pain practices and to obtain current peri-procedural protocols. DESIGN: We faxed a one-page questionnaire to 105 United States pain practices identified using the directory of the American Pain Society. Fifty-seven academic and private pain practices (54%) responded and were included in the analysis. RESULTS: Monitoring devices such as electrocardiogram (EKG), blood pressure, and pulse oximetry are not universally employed for cervical or lumbar spinal procedures. Even procedures that are often performed by anesthesiologists in operating rooms, such as Bier blocks, are not monitored in a uniform manner when performed in pain clinics. Establishment of intravenous access for procedures also varies among practitioners. Most (72%) practices had treated patients with vasovagal reactions over the past 12 months, but only 42% had simulated cardiac arrests to prepare for these situations. CONCLUSION: While various trends in peri-procedural care are observable, standards of care are not well established. In order to minimize complications associated with interventional pain management techniques, the pain management community should agree on safety guidelines for all procedures, much as these advocated by the American Society of Anesthesiology for surgical anesthetic care.

Journal Article↗
PubMed2004

Advanced age, anticoagulation intensity, and risk for intracranial hemorrhage among patients taking warfarin for atrial fibrillation.

BACKGROUND: The risk for atrial fibrillation-associated stroke increases at low anticoagulation intensities. However, higher intensities increase hemorrhage risk. Optimal use of warfarin for atrial fibrillation requires precise information on the risk for intracranial hemorrhage as a function of patient age and anticoagulation intensity. OBJECTIVE: To examine the relationship of age, anticoagulation intensity, and risk for intracranial hemorrhage. DESIGN: Case-control study. SETTING: Academic medical center. PATIENTS: 170 case-patients who developed intracranial hemorrhage during warfarin therapy and 1020 matched controls who did not; both case-patients and controls were taking warfarin for atrial fibrillation. MEASUREMENTS: The authors performed multivariable conditional logistic regression to determine the odds of intracranial hemorrhage with regard to age and international normalized ratio (INR), controlling for comorbid conditions and aspirin use. RESULTS: Case-patients were older than controls (median age, 78 years vs. 75 years; P < 0.001) and had higher median INRs (2.7 vs. 2.3; P < 0.001). The risk for intracranial hemorrhage increased at 85 years of age or older (adjusted odds ratio, 2.5 [95% CI, 1.3 to 4.7]; referent age, 70 to 74 years) and at an INR range of 3.5 to 3.9 (adjusted odds ratio, 4.6 [CI, 2.3 to 9.4]; referent INR, 2.0 to 3.0). The risk for intracranial hemorrhage at INRs less than 2.0 did not differ statistically from the risk at INRs of 2.0 to 3.0 (adjusted odds ratio, 1.3 [CI, 0.8 to 2.2]). LIMITATIONS: Although duration of anticoagulation has been associated with hemorrhage in other studies, the current study could not control for this potential confounder. CONCLUSIONS: The risk for intracranial hemorrhage increases at age 85 years. International normalized ratios less than 2.0 were not associated with lower risk for intracranial hemorrhage compared with INRs between 2.0 and 3.0. Therefore, anticoagulation management should focus on maintaining INRs in the 2.0 to 3.0 range, even in elderly patients with atrial fibrillation, rather than targeting INRs less than 2.0. Similarly, INRs of 3.5 or greater should be avoided.

Age Factors↗
PubMed2004

Soluble guanylate cyclase activator reverses acute pulmonary hypertension and augments the pulmonary vasodilator response to inhaled nitric oxide in awake lambs.

BACKGROUND: Inhaled nitric oxide (NO) is a potent and selective pulmonary vasodilator, which induces cGMP synthesis by activating soluble guanylate cyclase (sGC) in ventilated lung regions. Carbon monoxide (CO) has also been proposed to influence smooth muscle tone via activation of sGC. We examined whether direct stimulation of sGC by BAY 41-2272 would produce pulmonary vasodilation and augment the pulmonary responses to inhaled NO or CO. METHODS AND RESULTS: In awake, instrumented lambs, the thromboxane analogue U-46619 was intravenously administered to increase mean pulmonary arterial pressure to 35 mm Hg. Intravenous infusion of BAY 41-2272 (0.03, 0.1, and 0.3 mg x kg(-1) x h(-1)) reduced mean pulmonary arterial pressure and pulmonary vascular resistance and increased transpulmonary cGMP release in a dose-dependent manner. Larger doses of BAY 41-2272 also produced systemic vasodilation and elevated the cardiac index. N(omega)-nitro-l-arginine methyl ester abolished the systemic but not the pulmonary vasodilator effects of BAY 41-2272. Furthermore, infusing BAY 41-2272 at 0.1 mg x kg(-1) x h(-1) potentiated and prolonged the pulmonary vasodilation induced by inhaled NO (2, 10, and 20 ppm). In contrast, inhaled CO (50, 250, and 500 ppm) had no effect on U-46619-induced pulmonary vasoconstriction before or during administration of BAY 41-2272. CONCLUSIONS: In lambs with acute pulmonary hypertension, BAY 41-2272 is a potent pulmonary vasodilator that augments and prolongs the pulmonary vasodilator response to inhaled NO. Direct pharmacological stimulation of sGC, either alone or in combination with inhaled NO, may provide a novel approach for the treatment of pulmonary hypertension.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2004

Donor-recipient gender mismatch in lung transplantation: impact on obliterative bronchiolitis and survival.

BACKGROUND: Because of the shortage of donor lungs, liberalization of donor selection criteria in terms of age, gas exchange, and smoking history has been proposed. METHODS: We evaluated a single-institution population of lung transplant recipients (n = 98) for donor-recipient gender matching. We measured overall survival, time to acute allograft rejection, and time to development of obliterative bronchiolitis (OB). RESULTS: We found significant improvement in overall survival for gender-mismatched donor and recipient pairs (p = 0.078) and a significantly shorter OB-free period for male donor and female recipient pairs (p = 0.017). CONCLUSION: These findings suggest that donor organ allocation based on gender may affect long-term survival and other outcomes after lung transplantation.

Acute Disease↗
PubMed2004

Pulmonary artery occlusion increases the ratio of diffusing capacity for nitric oxide to carbon monoxide in prone sheep.

OBJECTIVE: To test the hypothesis that the ratio of diffusing capacity of the lung for nitric oxide (DLno) to diffusing capacity of the lung for carbon monoxide (DLco) would be affected by occlusion of a fraction of the pulmonary vascular bed. DESIGN: Interventional physiologic study. SETTING: Animal laboratory of a university hospital. SUBJECTS: Thirteen sheep. INTERVENTIONS: We simultaneously measured single-breath DLno and DLco in anesthetized and mechanically ventilated sheep (fraction of inspired oxygen [Fio(2)] of 1.0) before and after pulmonary artery occlusion by inflation of a balloon (n = 6), and by autologous clot embolism (n = 4). To see if the effect also occurred on Fio(2) of 0.21, four animals were studied during ventilation with room air, one of which was also in the Fio(2) of 1.0 group (14 total experiments with 13 sheep). RESULTS: On Fio(2) of 1.0, the mean DLno/Dlco ratio rose by 35% from 4.76 +/- 0.41 in control to 6.42 +/- 0.82 after balloon occlusion (p = 0.002), and by 54% from 7.55 +/- 2.09 to 11.6 +/- 2.61 (p = 0.005) after autologous clot embolism (+/- SD). An equivalent relative increase of 27% took place during ventilation with room air, but the DLno/DLco ratio was lower (3.14 +/- 0.22 in control and 3.98 +/- 0.38 after balloon occlusion). Independent of the method of obstruction or Fio(2), the increase in DLno/DLco ratio was mostly due to a drop in DLco. The DLno/Dlco ratio reduced much of the intersubject variability of either DLno or DLco alone. CONCLUSION: The DLno/DLco ratio increased after pulmonary artery occlusion regardless of the method of occlusion or Fio(2). This increase may be a result of a greater sensitivity of DLco than DLno to a regional reduction in capillary blood flow.

Animals↗
PubMed2003

Anticoagulation therapy for stroke prevention in atrial fibrillation: how well do randomized trials translate into clinical practice?

CONTEXT: Warfarin has been shown to be highly efficacious for preventing thromboembolism in atrial fibrillation in randomized trials, but its effectiveness and safety in clinical practice is less clear. OBJECTIVE: To evaluate the effect of warfarin on risk of thromboembolism, hemorrhage, and death in atrial fibrillation within a usual care setting. DESIGN: Cohort study assembled between July 1, 1996, and December 31, 1997, and followed up through August 31, 1999. SETTING: Large integrated health care system in Northern California. PATIENTS: Of 13,559 adults with nonvalvular atrial fibrillation, 11,526 were studied, 43% of whom were women, mean age 71 years, with no known contraindications to anticoagulation at baseline. MAIN OUTCOMES: Ischemic stroke, peripheral embolism, hemorrhage, and death according to warfarin use and comorbidity status, as determined by automated databases, review of medical records, and state mortality files. RESULTS: Among 11,526 patients, 397 incident thromboembolic events (372 ischemic strokes, 25 peripheral embolism) occurred during 25,341 person-years of follow-up, and warfarin therapy was associated with a 51% (95% confidence interval [CI], 39%-60%) lower risk of thromboembolism compared with no warfarin therapy (either no antithrombotic therapy or aspirin) after adjusting for potential confounders and likelihood of receiving warfarin. Warfarin was effective in reducing thromboembolic risk in the presence or absence of risk factors for stroke. A nested case-control analysis estimated a 64% reduction in odds of thromboembolism with warfarin compared with no antithrombotic therapy. Warfarin was also associated with a reduced risk of all-cause mortality (adjusted hazard ratio, 0.69; 95% CI, 0.61-0.77). Intracranial hemorrhage was uncommon, but the rate was moderately higher among those taking vs those not taking warfarin (0.46 vs 0.23 per 100 person-years, respectively; P =.003, adjusted hazard ratio, 1.97; 95% CI, 1.24-3.13). However, warfarin therapy was not associated with an increased adjusted risk of nonintracranial major hemorrhage. The effects of warfarin were similar when patients with contraindications at baseline were analyzed separately or combined with those without contraindications (total cohort of 13,559). CONCLUSIONS: Warfarin is very effective for preventing ischemic stroke in patients with atrial fibrillation in clinical practice while the absolute increase in the risk of intracranial hemorrhage is small. Results of randomized trials of anticoagulation translate well into clinical care for patients with atrial fibrillation.

Aged↗
PubMed2003

Effect of intensity of oral anticoagulation on stroke severity and mortality in atrial fibrillation.

BACKGROUND: The incidence of stroke in patients with atrial fibrillation is greatly reduced by oral anticoagulation, with the full effect seen at international normalized ratio (INR) values of 2.0 or greater. The effect of the intensity of oral anticoagulation on the severity of atrial fibrillation-related stroke is not known but is central to the choice of the target INR. METHODS: We studied incident ischemic strokes in a cohort of 13,559 patients with nonvalvular atrial fibrillation. Strokes were identified through hospitalization data bases and validated on the basis of medical records, which also provided information on the use of warfarin or aspirin, the INR at admission, and coexisting illnesses. The severity of stroke was graded according to a modified Rankin scale. Thirty-day mortality was ascertained from hospitalization and mortality files. RESULTS: Of 596 ischemic strokes, 32 percent occurred during warfarin therapy, 27 percent during aspirin therapy, and 42 percent during neither type of therapy. Among patients who were taking warfarin, an INR of less than 2.0 at admission, as compared with an INR of 2.0 or greater, independently increased the odds of a severe stroke in a proportional-odds logistic-regression model (odds ratio, 1.9; 95 percent confidence interval, 1.1 to 3.4) across three severity categories and the risk of death within 30 days (hazard ratio, 3.4; 95 percent confidence interval, 1.1 to 10.1). An INR of 1.5 to 1.9 at admission was associated with a mortality rate similar to that for an INR of less than 1.5 (18 percent and 15 percent, respectively). The 30-day mortality rate among patients who were taking aspirin at the time of the stroke was similar to that among patients who were taking warfarin and who had an INR of less than 2.0. CONCLUSIONS: Among patients with nonvalvular atrial fibrillation, anticoagulation that results in an INR of 2.0 or greater reduces not only the frequency of ischemic stroke but also its severity and the risk of death from stroke. Our findings provide further evidence against the use of lower INR target levels in patients with atrial fibrillation.

Administration, Oral↗
PubMed2003

Functional recovery following rehabilitation after hemorrhagic and ischemic stroke.

OBJECTIVES: To quantify recovery after rehabilitation therapy and to identify factors that predicted functional outcome in survivors of intracerebral hemorrhage (ICH) compared with cerebral infarction. DESIGN: Retrospective study of consecutive ICH and cerebral infarction admissions to a rehabilitation hospital over a 4-year period. SETTING: Free-standing urban rehabilitation hospital. PARTICIPANTS: A total of 1064 cases met the inclusion criteria (545 women, 519 men; 871 with cerebral infarction, 193 with ICH). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Functional status was measured using the FIM trade mark instrument, recorded at admission and discharge. Recovery was quantified by the change in FIM total score (DeltaFIM total score). Outcome measures were total discharge FIM score and DeltaFIM total score. Univariate and multivariate analyses were performed. RESULTS: Total admission FIM score was higher in patients with cerebral infarction than in patients with ICH (59 vs 51, P=.0001). No difference in total discharge FIM score was present. Patients with ICH made a significantly greater recovery than those with cerebral infarction (DeltaFIM total score, 28 vs 23.3; P=.002). On multivariate analysis, younger age, longer length of stay, and admission FIM cognitive subscore independently predicted total discharge FIM and DeltaFIM total score. The severity of disability at admission, indicated by total admission FIM score, independently predicted total discharge FIM score, but not DeltaFIM total score. The ICH patients with the most severely disabling strokes had significantly greater recovery than cerebral infarction patients with stroke of similar severity. CONCLUSIONS: The patients with ICH had greater functional impairment than the cerebral infarction patients at admission, but made greater gains. Patients with the most severely disabling ICH improved more than those with cerebral infarction of comparable severity. Initial severity of disability, age, and duration of therapy best predicted functional outcome after rehabilitation.

Activities of Daily Living↗
PubMed2003

Use of diagnostic testing in the emergency department for patients presenting with non-traumatic abdominal pain.

The objective of the study was to measure the utilization and diagnostic value of tests used in the Emergency Department (ED) on patients with undifferentiated non-traumatic abdominal or flank pain. Specific goals were to measure how often these tests led to changes in diagnosis or disposition, which tests were most commonly used, and which tests providers considered most helpful. We conducted a pilot single-center, prospective descriptive study, enrolling all eligible adult patients who presented to our ED with non-traumatic abdominal or flank pain during defined hours of our intake period. Based on serial provider interviews pre- and post-testing, we measured the frequency of change of most likely diagnosis and disposition, which tests were performed, and the provider-perceived value of tests. We enrolled 124 subjects with a mean age of 44 years; 27% were admitted. Testing led to a change in most likely diagnosis in 37% of subjects, and in disposition in 41%. Frequency of diagnostic test use varied from a high of 93% for CBC to 6% for a blood or urine culture. Overall, 65% of patients had at least one imaging study performed, and 39% had an abdominal/pelvic computed tomography (CT) scan. Over all subjects, providers identified the most useful tests as the CT scan (31%) and urinalysis (17%). In conclusion, among ED patients who presented with non-traumatic abdominal or flank pain to one academic center, the pre-test most likely diagnosis and disposition were changed based on the ED evaluation in over one-third of subjects. Almost all received blood tests and two-thirds received one or more imaging studies. Based on providers' subjective opinions, the most valuable tests were the abdomino/pelvic CT scan and the urinalysis.

Abdomen↗
PubMed2003

The effect of glycoprotein IIb/IIIa receptor inhibitor on the microcirculation in patients undergoing high-risk coronary stenting; a prospective, randomized study.

OBJECTIVES: We evaluated the effect of the glycoprotein IIb/IIIa inhibitor, tirofiban, on the microcirculation measured by Doppler coronary flow reserve (CFR) in patients undergoing high-risk coronary stenting. BACKGROUND: The mechanisms by which glycoprotein IIb/IIIa inhibitors benefit patients undergoing high-risk angioplasty are not fully understood. This may be due to prevention of distal embolization of the coronary clot at the site of angioplasty. METHODS: Thirty two consecutive patients with acute coronary syndrome within 72 hours or with high-risk angiographic features were randomized into 2 groups. Group A (n = 17) received tirofiban (10 microg/kg bolus followed 0.15 microg/kg/min). Group B (n = 15) received placebo bolus and infusion. Coronary flow reserve was measured by Doppler wire technique at baseline, post balloon angioplasty and post-stenting. Platelet aggregation was measured at baseline, 10 minutes, 6 hours and 12 hours post bolus. RESULTS: There was no significant difference in CFR between the groups at baseline and after balloon angioplasty. Post-stenting CFR, however, was significantly higher in the group pretreated with tirofiban (2.94 vs. 2.25, p = 0.014). The inhibition of platelet aggregation was 94% at 10 minutes, 97% at 6 hours and 94% at 12 hours in the tirofiban group. CONCLUSION: In patients undergoing high-risk coronary stenting, tirofiban protects and improves the microcirculation measured by Doppler wire technique. This may be due to prevention of distal embolization of clot by tirofiban and explain the clinical benefit.

Aged↗
PubMed2003

The predictive value of sympathetic block for the success of spinal cord stimulation.

OBJECTIVE: The purpose of this study was to assess the predictive value of response to sympathetic blockade (SB) on the success rate of spinal cord stimulation (SCS) in patients with complex regional pain syndrome. METHODS: We performed a retrospective study on 23 patients with complex regional pain syndrome who underwent both SB and subsequent SCS trials in the past 3 years at the Massachusetts General Hospital Pain Center, Boston, MA, and Walter Reed Army Medical Center, Washington, DC. Fifteen of these patients underwent permanent placement of an SCS device, and pain relief at 1- and 9-month follow-up was recorded. RESULTS: Among the 23 patients included in the study, those having transient pain relief with SB were more likely to have a positive SCS trial: all 13 with positive SB had good pain relief during the trial, compared with only 3 of the 10 with negative SB (100% versus 30%, P < 0.001). Among the 10 patients with negative SB, 7 noted poor pain relief during the trial despite adequate coverage, and they did not undergo placement of a permanent device. Among the patients who underwent permanent placement of an SCS device, those who received good pain relief with SB were more likely to have greater than 50% pain relief at 1-month follow-up (100% versus 33%, P = 0.029) and 9-month follow-up (87.5% versus 33.3%, P = 0.15). CONCLUSION: We conclude that patients with good response to SB before SCS are more likely to have a positive response during their SCS trial and long-term pain relief after placement of permanent SCS device.

Adult↗
PubMed2002

Oral anticoagulants vs aspirin in nonvalvular atrial fibrillation: an individual patient meta-analysis.

CONTEXT: Patients with nonvalvular atrial fibrillation (AF) have an increased risk of stroke and other vascular events. OBJECTIVE: To compare the risk of vascular and bleeding events in patients with nonvalvular AF treated with vitamin K -inhibiting oral anticoagulants or acetylsalicylic acid (aspirin). DESIGN: Pooled analysis of patient-level data from 6 published, randomized clinical trials. PATIENTS: A total of 4052 patients with AF randomly assigned to receive therapeutic doses of oral anticoagulant or aspirin with or without low-dose oral anticoagulants. MAIN OUTCOME MEASURES: Ischemic and hemorrhagic stroke, other cardiovascular events, all-cause death, and major bleeding events. Person-year incidence rates were calculated to provide crude comparisons. Relative efficacy was assessed using proportional hazards modeling stratified by study. The variation of the oral anticoagulant's relative effect by pertinent patient factors was explored with interaction terms. All analyses were conducted using the intention-to-treat principle. RESULTS: Patients receiving oral anticoagulant and aspirin were balanced for important prognostic factors. There was no significant heterogeneity between trials in the relative efficacy of oral anticoagulant vs aspirin for any outcome. Patients receiving oral anticoagulant were significantly less likely to experience any stroke (2.4 vs 4.5 events per 100 patient-years; hazard ratio [HR], 0.55; 95% confidence interval [CI], 0.43-0.71), ischemic stroke (HR, 0.48; 95% CI, 0.37-0.63), or cardiovascular events (HR, 0.71; 95% CI, 0.59-0.85) but were more likely to experience major bleeding (2.2 vs 1.3 events per 100 patient-years; HR, 1.71; 95% CI, 1.21-2.41). The reduction in ischemic stroke risk was similar in patients with paroxysmal AF (1.5 vs 4.7 events per 100 patient-years; HR, 0.32; 95% CI, 0.16-0.61; P<.001). Treating 1000 patients with AF for 1 year with oral anticoagulant rather than aspirin would prevent 23 ischemic strokes while causing 9 additional major bleeds. Overall all-cause survival did not differ but appeared to improve for oral anticoagulant patients 3 years after therapy was started. CONCLUSIONS: Compared with aspirin, oral anticoagulant significantly decreases the risk of all strokes, ischemic strokes, and cardiovascular events for patients with nonvalvular chronic or paroxysmal AF but modestly increases the absolute risk of major bleeding. The balance of benefits and risks varies by patient subgroup.

Administration, Oral↗