Incorrect Frequency Research Articles

Patient‐Completed Medication Histories versus those Obtained by a Pharmacist in a Pre‐admission Clinic

ABSTRACTAimTo evaluate the accuracy and completeness of patient‐completed medication histories to those obtained by a pharmacist in a pre‐admission surgical clinic.MethodThis prospective study was conducted over 3‐weeks with patients attending a pre‐admission surgical clinic. Consecutive patients had a pre‐admission assessment with the pre‐admission clinic pharmacist. Comparison was made regarding the accuracy of information between patient‐completed medication history and assessment by the pre‐admission clinic pharmacist.Results150 patients were enrolled −33 (22%) had a patient‐completed questionnaire that was totally correct. There was an average of 3.9 drug discrepancies per patient‐completed medication history. The discrepancies included: omitted drugs (317), incorrect doses (24), doses omitted (110), dosing frequency incorrect (24) or dosing frequency omitted (63). The adverse drug reaction status was recorded correctly on 85% of patient‐completed medication histories.ConclusionPatient‐completed medication histories used in a pre‐admission surgical clinic were not accurate in 4 out of 5 patients. Pharmacists in a pre‐admission clinic can ensure the availability of an accurate medication history.

Medication history reconciliation by pharmacists in an inpatient behavioral health unit

The effectiveness of a pharmacy-obtained medication history on the medication reconciliation process in the behavioral health unit (BHU) of a community hospital was studied. Patients admitted to the BHU of a 411-bed, not-for-profit hospital from 6 a.m. on Monday through 12 p.m. on Friday from September 1, 2005, through October 6, 2005, were candidates for the study. Within 18 hours of admission to the BHU and after the medication history had been obtained by a nurse, a pharmacy technician gathered patient demographic and medication information from the chart and the patient's medication bottles. Once the technician completed the documentation, the pharmacist was notified of a new admission. The pharmacist reviewed the collected documentation and patient chart before interviewing the patient. Of the 54 patients who met the study's inclusion criteria, 91% were seen by a pharmacist within 18 hours of admission. The mean +/- S.D. time delay to interview the patient was 11.6 +/- 5.1 hours. Pharmacists spent a mean of 13.9 minutes completing patients' medication histories. The mean +/- S.D. number of medications identified by nursing on admission was 4.0 +/- 3.2, compared with 5.3 +/- 3.7 identified by pharmacists (p < 0.05). The mean number of medication discrepancies identified per patient was 2.9. Of the discrepancies, 48% were related to an omitted or incorrect medication, 31% to an omitted or incorrect dose, and 13% to an omitted or incorrect frequency; 8% were categorized as miscellaneous. Pharmacists' participation in obtaining patients' medication histories through chart review and patient interview increased the effectiveness of the medication reconciliation process in an inpatient BHU.

Representation of acoustic signals in the human cochlea in presence of a cochlear implant electrode

Background: In subjects with remaining low frequency hearing, combined electric-acoustic stimulation (EAS) of the auditory system is a new therapeutic perspective. Intracochlear introduction of a cochlear implant electrode, however, may alter the biomechanical properties of the inner ear and thus affect perception of acoustic stimuli. Study design: Based on histological observations of morphologic changes after cochlear implantation in cadaveric and post mortem studies the effects of basilar membrane (BM) stiffening in the ascending basal and middle turns of the cochlea due to close contact of the BM with the electrode were simulated in a 3D-computational finite element model of the inner ear. To verify our simulated results, pre- and postoperative pure-tone audiograms of 13 subjects with substantial residual hearing, who underwent cochlear implantation, were evaluated. Results: In the scenario of partial BM-fixation, acoustic energy of middle (2 kHz) and high (6 kHz) frequency was focused basally and apically to the fixed section, increasing BM displacement amplitudes up to 6 dB at a stimulation level of 94 dB (SPL). Lower frequencies were not affected by fixation in the basal and middle turn of the cochlea. In implanted subjects, a small but significant decrease of thresholds was observed at 1.5 kHz, a place in tonotopy adjacent to the tip region of the implanted electrode. Conclusion: Our model suggests that stiffening of the basilar membrane adjacent to an implanted electrode into the basal and middle cochlear turn did not affect BM movement in the low frequency area. Focussing of acoustic energy may increase perception in regions adjacent to the fixed section. Observations in implanted subjects were concordant with our model predictions. High frequencies, however, should not be amplified in patients using EAS to avoid disturbances in discrimination due to tonotopically incorrect frequency representation.

Investigation of Periodic-Disturbance Identification and Rejection in Spacecraft

Spacecraft periodic-disturbance rejection using a realistic spacecraft hardware simulator and its associated models is investigated. The effectiveness of the dipole-type disturbance rejection filter on the current realistic nonlinear rigid-body spacecraft model is validated. However, it is shown that the rejection filter is not robust to disturbance frequency uncertainty. Therefore, system identification techniques are needed if the disturbance frequency is unknown or changing. Based on experience with the current test bed, two simple closed-loop system identification methods are introduced to experimentally identify the disturbance frequency using data from the control input torque signal. It is shown that an incorrect filter frequency results in beating of the control input torque. Examination of the beat envelope leads to tuning of the rejection filter. I. Introduction

A Method of Automatically Searching the Sampling Frequency and Sampling Phase for Graphic Digitizer in Pixelated Display Applications

When analog red, green, blue (RGB) signals of a video/graphic image need to be displayed on pixelated display devices, graphic digitizers have to be utilized to convert the analog signals to digital signals. In such an application choosing correct sampling frequency for the digitizers is essential since an incorrect frequency will impair the recovery of images encoded in the analog signals. This article presents an algorithm that searches automatically for the sampling frequency. The phase of the sampling clock is also critical since inadequate phase control can create undesirable visible artifacts. Thus, a second algorithm for automatically searching for the appropriate sampling phase is presented in this article as well. These algorithms can be applied in pixelated display applications.

Inappropriate Medication Use in Elderly Lebanese Outpatients

Inappropriate use of medications has become an international cause for concern in geriatric patients, who are at high risk of drug-related morbidity. This study is the first attempt to determine the prevalence of inappropriate drug use in elderly Lebanese outpatients, using community pharmacy data, and to identify factors that predict potentially inappropriate drug intake in this population. Records of elderly patients aged > or =65 years were selected from different community pharmacies. Each patient profile was reviewed and to confirm patient record information, in-person interviews were conducted with elderly patients between November 2004 and May 2005 by qualified pharmacists. Based on a literature review describing guidelines for the inappropriate use of medications in the elderly, courses of therapy were assessed and classified as either appropriate or inappropriate. Courses of therapy that were judged inappropriate were further classified according to the specific area of inappropriate use (i.e. Beers' criteria, duplicate therapy, indication, dose, dose frequency including missing doses, duration and discontinuation of therapy, adverse effects, drug-drug and/or drug-disease interactions, and poor memory). Statistical analyses were performed to estimate the prevalence of inappropriate medication use and to identify potentially predictive factors of such use arising from patients' sociodemographic characteristics, health factors and drug regimen intake. A total of 350 elderly patient profiles were reviewed, from which 277 evaluable records were obtained. More than half (59.6%) of the patients taking drugs at the time of the study were taking at least one inappropriate medication. Inappropriate medication use was most frequently identified in terms of Beers' criteria (22.4%), missing doses (18.8%) or incorrect frequency of administration of drugs (13.0%). Factors predicting potentially inappropriate drug intake included female sex (65.7% vs 53.3% for males, p = 0.03) and alcohol intake (p = 0.007). There were also significant associations between the likelihood of use of an inappropriate drug and (i) increased number of medical illnesses (p < 0.00002); and (ii) consumption of an over-the-counter drug (OTC) and/or prescription drug (p = 0.048 and p = 0.0035, respectively). The likelihood of use of an inappropriate drug was higher again when patients concurrently used both OTC and prescription drugs (p < 0.0002). The present study is the first to describe and assess inappropriate medication use by elderly outpatients in the Lebanese community setting. With increasing availability of newer and more appropriate medications, use of potentially inappropriate drugs may decrease. Pharmacists have a major role to play in counselling patients about the importance of appropriate drug use.

Impact of a Pharmacy-Initiated HIV Admission Note on Medication Errors within an Academic Hospital

Purpose Medication errors occur frequently in the medical management of patients infected with human immunodeficiency virus (HIV). Recent studies propose the use of a pharmacy admission note to help identify and prevent such errors during hospitalization. However, a clear reduction in the number of antiretroviral medication errors utilizing an admission note within a large, academic hospital has yet to be confirmed. Methods A retrospective, chart-review of hospitalized HIV-seropositive patients 1 year prior to and after implementation of an admission note policy was performed with the expedited Institutional Review Board (IRB) approval. Antiretroviral medication errors were identified and compared to documented pharmacy interventions at the time of admission. Results Twenty-seven antiretroviral medication errors existed in the pre-policy period (n = 32 admissions), with no identification or correction by pharmacy services at the time of admission. Forty-six antiretroviral medication errors were detected in the post-policy period (n = 59 admissions), of which three errors were identified in pharmacy admission notes. Common antiretroviral medication errors in the pre-policy period included incorrect dosing frequency (33.3%) and incorrect drug strength (33.3%). This contrasts with the post-policy period, during which the most frequent antiretroviral medication errors included missing antiretroviral components of known regimens (19.6%) and lack of renal or hepatic dosage adjustment (15.2%). Overall, no improvement in detection and reconciliation of medication errors occurred with admission note implementation. Conclusions Potential obstacles in the effective use of an admission note to reduce errors do exist. Strategies for improved outcomes in our academic hospital will focus on improved training of general pharmacy staff in HIV management, providing accessible online resources, and emphasizing reconciliation between outpatient and inpatient medication regimens.

Influence of the long-range exchange effect on dynamic polarizability

The long-range interaction in density functional theory (DFT) is corrected using a partition technique of the two-electron operator when applied in the equation of motion (EOM) on the first-order density matrix. While the correction produces a minor effect on the static polarizabilities of small molecules, it improves the overestimated Cauchy coefficients of small molecules by the DFT without the correction. The same technique is applied to compute the polarizabilities of long chain molecules, a long standing problem of DFT. The overestimations by the DFT without the correction are remarkably improved for hydrogen chains and polyacetylene. Finally, the method is applied to compute the dynamic polarizabilities of C4H6 and C12H14. The frequency dependencies obtained by the DFT with the long-range correction (LRC) are different from that obtained by the DFT without LRC and similar to that obtained by the HF. The adiabatic approximation taken in the TDDFT of the first-order density matrix without LRC causes complete neglect of the interaction among anti-symmetric modes in the EOM, which plays an important role in the near-resonance situation and provides an incorrect frequency dependence.

Medication Errors in an Internal Medicine Department. Evaluation of a Computerized Prescription System

Evaluation of a computerized physician order entry in an Internal Medicine Department, with a unit-dose distribution system. Pharmacy Department, Internal Medicine Department. S. Francisco Xavier Hospital, Lisbon, Portugal. This study was carried out in December 2001 and January 2002. After two years experience of the CPOE system, medication errors were evaluated prospectively, in an internal medical department of a 360-bed academic hospital. Data were collected once a week. Pharmacists reviewed all medical prescriptions as part of their routine work. Medication errors detected were recorded on a data collection form with a design based on the types of errors as defined by the American Society of Hospital Pharmacists (ASHP). Completed forms were reviewed and medication errors were classed according to ASHP guidelines. A total of 2268 orders were monitored (162 patients). In these orders, 73 medication errors (22.4% of the patients) were detected and documented (59 prescribing errors and 14 monitoring errors). The most common prescribing errors were deficiencies related to the right class but wrong drug (28.3%): omeprazole vs. ranitidine/sucralfate in stress ulcer prophylaxis; incorrect dose (30%) and unclear orders (13.3%). Errors related to incorrect frequency of administration (5%); maintenance of IV route (5%); duplicated drug therapy (11.7%); drug interactions (1.7%) and length of therapy (3.3%) were also detected. The 14 monitoring errors detected were failures to review a prescribed regimen for appropriateness and detection of problems. Computerized prescription order entry has demonstrated effectiveness in eliminating medication errors related to transcribing and patient identification. Nevertheless, medication errors related to prescription and monitoring still occur. The use of clinical decision support systems and pharmacist involvement is vital to achieve maximum medication safety and reduce medication error rates.

Prevalence and Causes of Medication Errors: A Review

Methods A literature search was conducted using Ovid Technologies/Medline from January 1966 to March 2002. The following search terms were used:medication errors, missed medications, omitted medications, missed dose, and missed treatment. Results Rates of different types of errors vary across series. For example, the rate with which the wrong drug was administered varies from 0% to 9%. The rate at which drugs were administered with the incorrect frequency ranged from 4% to 25%. Finally, the rate with which drugs were inadvertently omitted ranged from 1.1% to 58%. Reasons commonly cited for missing medications were patients’ unavailability, intolerance of the medication, and the clinicians’ perception that the medication was not needed. Conclusions Greater attention to reducing medication errors is needed. Proposed strategies include implementing unit dose pharmacy systems and physician order entry systems, enhancing interdisciplinary communication, educating patients regarding their medications, and increased attention to system failures.

Cyclic genotyping strategies. II: True and perceived utilities under incorrect allele frequency assumptions

SummaryThis paper investigates the potential problems associated with assuming incorrect population frequencies for segregation analysis when animals are genotyped one by one in a cyclic fashion with segregation analysis carried out at each cycle. The base population allele frequencies of 0.1 and 0.5 studied, with the incorrect frequencies assumed for segregation analysis of 0.5 and 0.1 respectively, were investigated on the basis of their covering the range of possible frequencies and the most erroneous assumption of frequencies. An index modelled using linear regression (LR) was employed to choose the next animal to be genotyped in each cycle, based on segregation analysis at the incorrect frequency. The resultant utility was evaluated both at the correct frequency giving actual utility and at the incorrect frequency, the perceived utility. The results are compared with those in which all segregation analysis was carried out at the correct base population allele frequency. The assumption of incorrect population frequency for segregation analysis leads to a decline in the predictive performances of both indices in terms of the true utility of prediction. When utility is also computed at the incorrect frequency to give perceived utility, the assumption of incorrect population frequency of q = 0.5 for segregation analysis of populations simulated at q = 0.1 leads to a perceived decline in the predictive performance of the LR index. However, the assumption of incorrect population frequency of q = 0.1 for segregation analysis of populations simulated at q = 0.5 leads to a perceived increased utility. This latter paradox is explained in terms of genotype probabilities with reference to the method of construction of the genotype probability index.

Effects of misspecification of allele frequencies on the power of Haseman‐Elston sib‐pair linkage method for quantitative traits

It is well known that the Haseman-Elston (H-E) sib-pair linkage method does not assume that the genetic model underlying the trait phenotype is known without error, although this assumption is made for marker loci. However, misspecification of allele frequencies at the marker locus decreases power when some or all parental genotypes are unknown. In this study, the power of the H-E sib-pair method was compared for different types of traits when some or all parental data were missing and allele frequencies at the marker loci were misspecified. Data were generated for a quantitative trait and marker loci in nuclear families using G.A.S.P. (V3.3). Three types of traits were simulated with two equifrequent alleles with a random environmental effect (10%, 30%, and 50%). The simulated data were analyzed using (i) one of the parent's marker data, and (ii) no parental marker data, with both correct and incorrect marker allele frequencies. This test is found to be robust in most of the situations considered except for a slight decrease in power when sample size is small and when the marker locus is not very polymorphic. © 2001 Wiley-Liss, Inc.

Biased resonance measurements as predictors of large-signal performance of PMN-PT

The large-signal performance of electrostrictive materials, such as lead magnesium niobate-lead titanate, is of critical importance to sonar and actuator designers. However, obtaining these large signal parameters properly, particularly under compressive prestress, is expensive and time consuming. The complexity of these measurements precludes them as a method for quickly and easily screening materials. Traditionally, resonance measurements, which otherwise are relatively simple to perform, have been used, but they suffer from the drawback that the material parameters obtained are at the incorrect frequency and under no prestress. Furthermore, the significance of the results of resonance measurements for nonlinear materials is unclear. It has recently been suggested [Hom and Shankar, IEEE Trans. Ultrason. Ferroelectr. Freq. Control UFFC-46, p. 1422, 1999] that dc biased resonance measurements on electrostrictive ceramics would be an accurate predictor of the coupling factor and optimum bias point. Here, dc biased resonance measurements on several formulations, with varying dielectric maximum temperatures, are analyzed to determine which composition has the highest predicted coupling factor. This prediction is compared with large signal quasistatic measurements conducted on NAVSEAs SDECS (stress-dependent electromechanical characterization system). The predictive ability of the resonance measurements is analyzed as a function of temperature. [Work supported by ONR.]

Bayesian 2-D deconvolution: effect of using spatially invariant ultrasound point spread functions.

Observed ultrasound images are degraded representations of the-true tissue reflectance. The specular reflections at boundaries between regions of different tissue types are blurred, and the diffuse scattering within homogenous regions causes speckle because of the oscillating nature of the transmitted pulse. To reduce both blur and speckle, we have developed algorithms for the restoration of simulated and real ultrasound images based on Markov random field models and Bayesian statistical methods. The algorithm is summarized here, although a more detailed description can be found in our companion paper [1]. Because the point spread function (psf) is unknown, we investigate the effects of using incorrect frequencies and sizes for the model psf during the restoration process. First, we degrade the images either with a known simulated psf or a measured psf. Then, we use different psf shapes during restoration to study the robustness of the method. We found that small variations in the parameters characterizing the psf, less than +/- 25% change in frequency, width, or length, still yielded satisfactory results. When altering the psf more than this, the restorations were not acceptable. The restorations were particularly sensitive to large increases in the restoring psf frequency. Thus, 2-D Bayesian restoration using a fixed psf may yield acceptable results as long as the true variant psfs have not varied too much during imaging.

Effects of misspecification of allele frequencies on the power of Haseman-Elston sib-pair linkage method for quantitative traits

It is well known that the Haseman-Elston (H-E) sib-pair linkage method does not assume that the genetic model underlying the trait phenotype is known without error, although this assumption is made for marker loci. However, misspecification of allele frequencies at the marker locus decreases power when some or all parental genotypes are unknown. In this study, the power of the H-E sib-pair method was compared for different types of traits when some or all parental data were missing and allele frequencies at the marker loci were misspecified. Data were generated for a quantitative trait and marker loci in nuclear families using G.A.S.P. (V3.3). Three types of traits were simulated with two equifrequent alleles with a random environmental effect (10%, 30%, and 50%). The simulated data were analyzed using (i) one of the parent's marker data, and (ii) no parental marker data, with both correct and incorrect marker allele frequencies. This test is found to be robust in most of the situations considered except for a slight decrease in power when sample size is small and when the marker locus is not very polymorphic.

Effects of Misspecification of Allele Frequencies on the Type I Error Rate of Model-Free Linkage Analysis

Linkage analyses of simulated quantitative trait data were performed using the Haseman-Elston (H-E) sib pair regression test to investigate the effects of inaccurate allele frequency estimates on the type I error rates of this test. Computer simulations generating a quantitative trait in nuclear families were performed using GASP [<citeref rid="ref001">1</citeref>]. Assuming no linkage, several data sets were simulated; they differed in marker allele numbers and frequencies, number of sib pairs and number of sibships. Each set of simulated data was analyzed using (1) all parental marker data, (2) half of the parental marker data, and (3) no parental marker data, using both correct and incorrect allele frequencies in the latter 2 cases. The H-E sib pair linkage method was found to be robust to misspecification of marker allele frequencies regardless of the number of alleles.

Caregiver knowledge and delivery of a commonly prescribed medication (albuterol) for children.

To evaluate caregiver knowledge and delivery of a prescription medication (albuterol) for children. Prospective convenience sample. Caregivers listing albuterol as one of their child's medications. Two urban, university-affiliated pediatric emergency departments. Caregivers were asked about their knowledge of the medication, the child's dose, frequency, duration of use, and where it was prescribed. In a mock scenario, they measured and demonstrated medication delivery to their child. Common measuring devices and formulations were offered. Forty-one caregivers were enrolled. Thirty-six (88%) were high school educated and 39 (95%) had a primary care provider. Twenty-six (63%) were out of medication, 7 (17%) stated an incorrect dose, 18 (44%) reported an incorrect frequency, and 10 (24%) stated an inadequate duration of use. Formulations chosen were liquid (n = 15, 37%), nebulizers (n= 15, 37%), and inhalers (n = 11, 27%). Metered dosing (metered-dosing inhaler or premixed solution) were chosen by 22 caregivers (54%), calibrated measuring tools (droppers, syringes) by 15 (37%), and noncalibrated delivery devices (teaspoon) by 4 (10%). An improper dose was measured by 9 (22%), and the dose intended was inaccurately measured by 7 (17%). All caregivers using a teaspoon inaccurately measured their intended dose of the liquid formulation. Metered dosing and calibrated measuring devices aided in the accurate delivery of this prescription medication. However, considerable concern exists with the use of noncalibrated measuring devices (teaspoons), improper frequency, and duration of use. Refilling of medication was also a concern since 63% were out of albuterol. Caregiver education on use, delivery, and refilling of medications must be stressed and assessed at all emergency department and primary care visits. In addition, metered dosing and the use of calibrated measuring devices should be encouraged.

Frequency Shifts and Master Equations for a Quantum Oscillator Coupled to a Reservoir

For a quantum oscillator coupled to a reservoir, master equations obtained under the assumptions of weak coupling and use of a rotating-wave Hamiltonian (RWA) are known to give incorrect frequency shifts. Here, we show that a calculation which does not invoke the RWA gives results for the frequency shifts, which agree with exact results for Lamb-type (temperatureT=0) shifts. However, for non-zeroT, we point out that, in general, corresponding energy and free energy shifts for the system require exact treatments since off-resonant contributions (which are automatically excluded in weak coupling calculations) are important in the case of super-Ohmic reservoirs.

Incorrect performance and lower EEG frequency in specific areas

Incorrect performance and lower EEG frequency in specific areas

Errors in prescribing HIV-1 protease inhibitors

The purpose of this study was to describe and quantify errors in dosage frequency associated with written medical orders, compared to manufacturer's recommendations and current therapeutic recommendations for protease inhibitors, for persons living with HIV disease/AIDS who were receiving home care services. A convenience sample was used for a univariate descriptive study to collect information from client records on the dosing intervals prescribed for three protease inhibitors: indinavir, ritonavir, and saquinavir. The study took place between December 1, 1996, and January 15, 1997, at a certified home health agency (CHHA) in New York City. The final sample accrued consisted of 202 adults who were receiving home care. The mean age of the sample was 42 years (SD = 9.43), ranging from 24 to 69 years. The majority were people of color, and Medicaid was the principle payor source for all health care needs. The main outcome measure was the number of errors in dosage frequency documented in written medical orders for protease inhibitors Protease inhibitors were ordered for 91 (45.1%) of the sample. Of the total number of medical orders for protease inhibitors, according to manufacturer's recommendations and current therapeutic recommendations, incorrect dosing schedules were noted in 36 (39.6%) of the records. Additional findings included errors in the dosages of drug prescribed and orders for protease inhibitors as monotherapy. Errors identified with ordering protease inhibitors included the incorrect frequency, the incorrect dose, and the ordering of protease inhibitor as a monotherapeutic agent instead of in combination with other recommended antiretroviral agents. Making clinicians aware of these problems may assist in reducing the incidence of these errors.