PubMed Health⌕ Search

Biomedical subjects

D L Simel

Publications and source records attributed to D L Simel.

At least 19 recordsLinked to original sources
PubMed1992

Clinical evaluation for sinusitis. Making the diagnosis by history and physical examination.

OBJECTIVE: To identify the most useful clinical examination findings for the diagnosis of acute and subacute sinusitis. DESIGN: Prospective comparison of clinical findings with radiographs. SETTING: General medicine clinics at a university-affiliated Veterans Affairs Medical Center. PATIENTS: Two hundred forty-seven consecutive adult men with rhinorrhea (51%), facial pain (22%) , or self-suspected sinusitis (27%) (median age, 50 years; median duration of symptoms, 11.5 days). MEASUREMENTS: Patients were examined by a principal investigator (86%) or by a staff general internist, internal medicine resident (postgraduate year 2 or 3), or physician assistant, all blinded to radiographic results. All examiners recorded the presence or absence of 16 historical items, 5 physical examination items, and the clinical impression for sinusitis (high, intermediate, or low probability). The criterion standard was paranasal sinus radiographs (4 views), which were interpreted by radiologists blinded to clinical findings. RESULTS: Thirty-eight percent of patients meeting entrance criteria had sinusitis. Sensitivity, specificity, and likelihood ratios were measured for clinical items. Logistic regression analysis showed five independent predictors of sinusitis: maxillary toothache (odds ratio, 2.9), transillumination (odds ratio, 2.7), poor response to nasal decongestants or antihistamines (odds ratio, 2.4), colored nasal discharge reported by the patient (odds ratio, 2.2), or mucopurulence seen during examination (odds ratio, 2.9). THe overall clinical impression was more accurate than any single finding: high probability (likelihood ratio, 4.7, intermediate (likelihood ratio, 1.4), low probability (likelihood ratio, 0.4). CONCLUSIONS: General internists, focusing on five clinical findings and their overall clinical impression, can effectively stratify male patients with sinus symptoms as having a high, intermediate, or low probability of sinusitis.

Adult↗
PubMed1991

Likelihood ratios with confidence: sample size estimation for diagnostic test studies.

Confidence intervals are important summary measures that provide useful information from clinical investigations, especially when comparing data from different populations or sites. Studies of a diagnostic test should include both point estimates and confidence intervals for the tests' sensitivity and specificity. Equally important measures of a test's efficiency are likelihood ratios at each test outcome level. We present a method for calculating likelihood ratio confidence intervals for tests that have positive or negative results, tests with non-positive/non-negative results, and tests reported on an ordinal outcome scale. In addition, we demonstrate a sample size estimation procedure for diagnostic test studies based on the desired likelihood ratio confidence interval. The renewed interest in confidence intervals in the medical literature is important, and should be extended to studies analyzing diagnostic tests.

Epidemiology↗
PubMed1991

A randomized controlled trial comparing quantitative informed consent formats.

Informed consent has been indirectly studied only in settings that do not replicate the actual consent process. We designed a sham study and randomly allocated adult ambulatory patients to receive one of two consent forms: Consent A (n = 52) described a randomized trial of usual treatment vs a new medication that "may work twice as fast as the usual treatment"; or Consent B (n = 48) that described a randomized trial of a new medication that "may work half as fast as the usual treatment". Patients randomized to Consent A were more likely to consent than those randomized to Consent B (consent rate A = 67%, consent rate B = 42%, p less than 0.01). Among patients who cited quantitative information, the difference in consent rate was even more marked (95% vs 36%, p less than 0.001); patients who did not cite quantitative information had equivalent consent rates. Patients who perceived minimal or severe symptoms had lower consent rates than those with mid-range symptom scores (chi 2(2) = 8.35, p = 0.015). Patients who recognize quantitative information will use it to make informed consent decisions.

Behavioral Research↗
PubMed1991

Anti-inflammatory effects of pentoxifylline in claudication.

We measured neutrophil elastase/alpha 1 proteinase inhibitor complex (E/alpha) levels by ELISA in plasma samples drawn from 19 patients with claudication, before and at 1 and 2 months after initiation of pentoxifylline (PTF), 400 mg. p.o. tid. Plasma E/alpha levels declined in all eight patients whose initial values were more than 300 ng elastase per ml. Whole blood viscosity (wbv) was reduced by two months' treatment in 12 of 14 patients tested. The relative change in wbv was significantly related to the relative change in E/alpha (R2 = 0.8), for patients with elevated initial E/alpha levels, suggesting a common or related mechanism for the two effects. Plasma crosslinked fibrin D-dimer fragments (XDP) measured by ELISA as indicators of coagulation activity were lower compared to pretreatment levels in 9 of 10 samples drawn when symptoms were improved on PTF, whereas they were increased in 6 of 9 samples drawn when symptoms were worse or unchanged. Plasma viscosity, C-reactive protein and alpha 1-acid-glycoprotein did not change significantly with PTF treatment. Together these findings are consistent with the possibility that reduced microvascular neutrophil activation and coagulation play a role in the clinical efficacy of PTF in intermittent claudication.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

Driving-impaired patients leaving the emergency department. The problem of inadequate instructions.

STUDY OBJECTIVE: We evaluated the frequency with which blood alcohol concentrations were obtained in emergency department patients with presumed alcohol impairment, whether physicians counseled impaired patients not to drive, and whether safe transportation was available. DESIGN: Retrospective chart review and search of the North Carolina Driver History file. SETTING: Emergency departments of a university and affiliated Veterans Affairs Medical Center (VAMC). PATIENTS: Consecutive adult patients at the university (n = 1554) and VAMC (n = 1461) emergency departments. Patients with presumed alcohol-induced impairment (university, 75; VAMC, 88) who did not require hospital admission were identified. Presumed alcohol-induced impairment was defined by any of the following: nurse or physician note specifying the patient was intoxicated; indication in the medical record that the patient had alcohol on their breath; claim by the patient of alcohol use the day of evaluation; or measurement of blood alcohol concentration. MEASUREMENTS AND MAIN RESULTS: Blood alcohol concentrations were measured in 80% of presumed alcohol-impaired university patients (median blood alcohol concentration, 45 mmol/L) and 68% of VAMC patients (median blood alcohol concentration, 58 mmol/L). Driving skills deteriorate with blood alcohol concentrations of 11 mmol/L or greater; however, 63% of university and 88% of VAMC patients with measured blood alcohol concentrations of 11 mmol/L or greater were still impaired when discharged. Only 3.5% of university and 8.7% of VAMC patients impaired at discharge were advised not to drive, whereas 31% of university and 20% of VAMC patients impaired at discharge were supervised by a responsible person. The prevalence of previous driving-while-impaired convictions was high (university, 34%; VAMC, 58%). CONCLUSIONS: Presumed alcohol-impaired patients seen in emergency departments frequently have blood alcohol concentrations measured. Despite documented evidence of driving impairment there is little evidence that such patients are counseled not to drive or that safe transportation home is available.

Adult↗
PubMed1990

Superficial migratory thrombophlebitis and factor XII deficiency.

A patient with painful migratory erythematous nodules for 7 years is presented. The nodules, which were localized on the lower and upper extremities, progressed to palpable cords. Multiple venograms showed no evidence of deep vein thrombosis. Skin biopsy specimens were diagnostic of superficial thrombophlebitis. There was no evidence of internal malignancy. Extensive evaluation for an underlying hypercoagulable state was remarkable for a factor XII level 17% of normal. The patient was unresponsive to a wide range of treatments. The recalcitrant nature of his disease and lack of deep venous involvement are unique. An underlying hypercoagulable state should be considered when the diagnosis of superficial migratory thrombophlebitis is considered.

Adult↗
PubMed1990

Effects of pentoxifylline administration on blood viscosity and leukocyte cytoskeletal function in patients with intermittent claudication.

We have previously shown that pentoxifylline, a drug used in intermittent claudication, causes depolymerization of actin in leukocytes in vitro. In this study we evaluated several parameters in peripheral blood obtained from 17 patients receiving pentoxifylline, before therapy and at 1 and 2 months after initiation of drug therapy. Total blood viscosity decreased at 1 month and was further reduced at 2 months. The plasma viscosity remained unchanged during the course of the therapy (1.770 +/- 0.147, 1.776 +/- 0.162, and 1.772 +/- 0.164 centipoise at 0, 1, and 2 months, respectively; mean +/- SD, n = 14 to 17). No changes were observed in stimulus-induced actin polymerization in granulocytes, concanavalin A-induced capping in granulocytes and lymphocytes, and anti-IgG-induced caps in lymphocytes, before and after therapy. Similarly, there was no difference in the magnitude of depolymerization caused by pentoxifylline when added in vitro. Thus none of the parameters altered by pentoxifylline treatment in vitro have been observed ex vivo in patients receiving this drug. However, the decrease in total blood viscosity along with unaltered plasma viscosity suggests that the rheology of the cellular elements is being affected by the administered drug. In addition to the direct effects on the cell membrane and the cytoskeleton, pentoxifylline may exert indirect effects through its inhibitory action on cytokine production. Subtle changes in a number of parameters in leukocytes, which taken alone fail to show demonstrable changes, might ultimately be responsible for the therapeutic benefit noted with pentoxifylline.

Actins↗
PubMed1989

Does determining serum alcohol concentrations in emergency department patients influence physicians' civil suit liability?

Emergency physicians may incur liability when impaired patients who have been treated and released are subsequently involved in traffic crashes. We surveyed attorneys to assess their perception of how serum alcohol determinations might influence their liability in civil suits. Overall, 63.9% of the attorneys surveyed would advise patients that they received potentially negligent care if they were impaired following treatment in the emergency department and were involved in a traffic crashes. Perceived liability was altered by physician behavior as follows: 43.1% of attorneys would advise clients that they received potentially negligent care when impairment was documented by a test for serum alcohol concentration and no advice was given regarding drunk driving, and 17.3% of attorneys would give similar advice when impairment was not documented by a test for serum alcohol concentration and no advice was given regarding drunk driving. In contrast, only 3.5% of attorneys would suggest possible negligence when impairment was documented by a test for serum alcohol concentration and with advice subsequently given not to drive. The coupling of diagnosing impairment by the serum alcohol concentration and driving advice is medically sensible and might result in minimal civil liability.

Accidents, Traffic↗
PubMed1988

Erythrocyte anisocytosis. Visual inspection of blood films vs automated analysis of red blood cell distribution width.

An improved anemia classification may be available by combining measures of red blood cell size variability with mean corpuscular volume. Visual inspection of the peripheral blood film allows semiquantitative description of anisocytosis while quantitative measures are determined from electronic cell counter analyzers' red blood cell distribution width. We evaluated correlations between semiquantitative and quantitative measures of anisocytosis for different groups of observers. Hematologists', medical students', and medical residents' semiquantitative assessment of anisocytosis correlated with the quantitative red blood cell distribution width. The interobserver variability demonstrated that all observers correlated with each other, while the intraobserver variability of semiquantitative anisocytosis demonstrated that observers were more precise than could be predicted by chance. However, the extreme precision of the red blood cell distribution width strongly suggests that it should be the "gold standard" for measuring red blood cell size variability.

Anemia↗
PubMed1988

Does maternal platelet-associated or platelet-bindable IgG correlate with levels in umbilical cord blood or colostrum during normal pregnancy?

Existing data regarding the ability to predict neonatal thrombocytopenia during maternal immune thrombocytopenia are confusing. We studied normal pregnancies (n = 20) to define normal values and the correlation between maternal and umbilical cord platelet counts, platelet-associated immunoglobulin G (IgG), and platelet-bindable IgG. The postpartum serum platelet-bindable IgG level was measured to evaluate peripartum changes and the correlation with colostrum platelet-bindable IgG (n = 6). The mean maternal platelet count was 181,500 cells/cm3 mm and the mean umbilical cord platelet count was 293,500 cells/mm3. The median maternal platelet-associated IgG was 803 molecules per platelet, umbilical cord platelet-associated IgG was 791 molecules per platelet, maternal platelet-bindable IgG was 92 molecules per platelet, and umbilical cord platelet-bindable IgG was 256 molecules per platelet. The postpartum median maternal platelet-bindable IgG was 333 molecules per platelet and for colostrum it was 297 molecules per platelet. No clinically useful correlations for predicting the neonatal platelet count during normal pregnancy were found. Normal pregnancies may have high levels of maternal- or umbilical cord platelet-associated IgG, perhaps due to nonspecific binding.

Blood Platelets↗
PubMed1988

Routine intravenous pyelograms before hysterectomy in cases of benign disease: possibly effective, definitely expensive.

Intraoperative ureteral injuries are potentially serious iatrogenic complications. Routine preoperative intravenous pyelograms might decrease the risk of such injuries during hysterectomy in cases of nonmalignant disease, but no prospective studies have been conducted to determine their effectiveness. Since gynecologists must frequently decide whether to obtain pyelograms, we used decision analysis to determine how costly routine pyelograms would be and under what circumstance pyelograms might be especially justifiable. Our cost-effectiveness study was based on decision analysis techniques, with the best available estimates from the literature, and on expert opinion. These estimates were varied over a broad range during a sensitivity analysis so as not to bias the results. At a baseline ureteral incidence injury rate of 0.5%, the marginal cost-effectiveness ratio indicates 833 pyelograms would be obtained to prevent a single injury and approximately $3.33 million would be spent to prevent a single death. As the probability of an injury increases, the marginal cost-effectiveness ratio is less dependent on the test efficacy and is more modest. Since abnormal ureteral anatomy probably predicts ureteral injury, we suggest selectively obtaining preoperative pyelograms only when the probability of an abnormality is high.

Contrast Media↗
PubMed1988

Does lacrimal duct occlusion decrease intraocular pressure in patients refractory to medical treatment for glaucoma? A randomized, sham-controlled, crossover trial.

We temporarily occluded lacrimal ducts with dissolvable collagen inserts in a randomized, double masked, sham-controlled crossover trial to test whether longer ocular contact of eye drops lowers intraocular pressure in patients with refractory glaucoma. Patients were randomized to the sequence temporary lacrimal duct occlusion----21 day washout----sham occlusion (6 patients), or the reverse order (5 patients); all maintained their usual medication. Compliance was greater than 90% for every patient as assessed by medication diaries kept by each patient's medication partner. There was no treatment effect (bivariate Wilcoxon chi 2 = 0.10, p = 0.95) or treatment-period interaction (chi 2 = 2.87, p = 0.24). However, whichever treatment was received first significantly lowered intraocular pressure (left eye first period X:[ipr50] = 3.0: [-6.0, -1.0] mmHg, right eye = -3.0:[-6.0, -1.0] mmHg, bivariate response chi 2 = 5.92, p = 0.05). Although lacrimal duct occlusion appears to have no clinical benefit, more careful supervision of eye drop administration may be efficacious for treating some patients with medically refractory glaucoma.

Collagen↗
PubMed1988

Blood alcohol measurements in the emergency department: who needs them?

We surveyed North Carolina emergency physicians to determine current medical practices regarding the use of blood alcohol concentrations using a hypothetical scenario. Most physicians (88 per cent) would not have obtained blood alcohol concentrations in a patient who had alcohol on his breath but was coherent and cooperative. For marginally impaired patients, more liberal use of blood alcohol concentrations and explicit instructions to avoid driving while impaired might improve patient care and promote highway safety.

Adult↗