11 resultados para PAC

em Queensland University of Technology - ePrints Archive


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The high burden of parental concern in children with chronic cough has been well documented. Acute cough in children (lasting less than 2 weeks) also has a significant impact on families, reflected by the number of doctor visits for cough. Currently there is no validated acute cough specific quality of life (QOL) measure for children. The objective of this study is to develop and validate an acute cough specific QOL questionnaire (PAC-QOL) for paediatric use. Here we present our data on item selection. Methods Two independent focus groups were conducted to determine relevant items. Parents discussed the impact of their child’s current or previous episodes of acute cough on their child, themselves and their family functioning. Transcripts were analyzed to determine whether discussions had reached an item saturation point. Items were also compared against our previously validated parent-centred children’s chronic cough specific QOL questionnaire (PC-QOL), which was used as a model. The newly developed acute cough specific QOL questionnaire is designed to assess the level of frequency of parents’ feelings and worry related to their child’s acute cough, using a 24-h time-point reference. Results Newly identified acute cough specific items include parental worry around whether or not they should take their child to a doctor or emergency department, and frequency of seeking assistance from friends and family. Conclusions While there are similarities between items identified for both acute and chronic cough, there are distinct features. Further data will be collected for item reduction and validation of this children’s acute cough specific QOL questionnaire.

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We present PAC-Bayes-Empirical-Bernstein inequality. The inequality is based on combination of PAC-Bayesian bounding technique with Empirical Bernstein bound. It allows to take advantage of small empirical variance and is especially useful in regression. We show that when the empirical variance is significantly smaller than the empirical loss PAC-Bayes-Empirical-Bernstein inequality is significantly tighter than PAC-Bayes-kl inequality of Seeger (2002) and otherwise it is comparable. PAC-Bayes-Empirical-Bernstein inequality is an interesting example of application of PAC-Bayesian bounding technique to self-bounding functions. We provide empirical comparison of PAC-Bayes-Empirical-Bernstein inequality with PAC-Bayes-kl inequality on a synthetic example and several UCI datasets.

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Background The accurate measurement of Cardiac output (CO) is vital in guiding the treatment of critically ill patients. Invasive or minimally invasive measurement of CO is not without inherent risks to the patient. Skilled Intensive Care Unit (ICU) nursing staff are in an ideal position to assess changes in CO following therapeutic measures. The USCOM (Ultrasonic Cardiac Output Monitor) device is a non-invasive CO monitor whose clinical utility and ease of use requires testing. Objectives To compare cardiac output measurement using a non-invasive ultrasonic device (USCOM) operated by a non-echocardiograhically trained ICU Registered Nurse (RN), with the conventional pulmonary artery catheter (PAC) using both thermodilution and Fick methods. Design Prospective observational study. Setting and participants Between April 2006 and March 2007, we evaluated 30 spontaneously breathing patients requiring PAC for assessment of heart failure and/or pulmonary hypertension at a tertiary level cardiothoracic hospital. Methods SCOM CO was compared with thermodilution measurements via PAC and CO estimated using a modified Fick equation. This catheter was inserted by a medical officer, and all USCOM measurements by a senior ICU nurse. Mean values, bias and precision, and mean percentage difference between measures were determined to compare methods. The Intra-Class Correlation statistic was also used to assess agreement. The USCOM time to measure was recorded to assess the learning curve for USCOM use performed by an ICU RN and a line of best fit demonstrated to describe the operator learning curve. Results In 24 of 30 (80%) patients studied, CO measures were obtained. In 6 of 30 (20%) patients, an adequate USCOM signal was not achieved. The mean difference (±standard deviation) between USCOM and PAC, USCOM and Fick, and Fick and PAC CO were small, −0.34 ± 0.52 L/min, −0.33 ± 0.90 L/min and −0.25 ± 0.63 L/min respectively across a range of outputs from 2.6 L/min to 7.2 L/min. The percent limits of agreement (LOA) for all measures were −34.6% to 17.8% for USCOM and PAC, −49.8% to 34.1% for USCOM and Fick and −36.4% to 23.7% for PAC and Fick. Signal acquisition time reduced on average by 0.6 min per measure to less than 10 min at the end of the study. Conclusions In 80% of our cohort, USCOM, PAC and Fick measures of CO all showed clinically acceptable agreement and the learning curve for operation of the non-invasive USCOM device by an ICU RN was found to be satisfactorily short. Further work is required in patients receiving positive pressure ventilation.

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We present new expected risk bounds for binary and multiclass prediction, and resolve several recent conjectures on sample compressibility due to Kuzmin and Warmuth. By exploiting the combinatorial structure of concept class F, Haussler et al. achieved a VC(F)/n bound for the natural one-inclusion prediction strategy. The key step in their proof is a d = VC(F) bound on the graph density of a subgraph of the hypercube—oneinclusion graph. The first main result of this paper is a density bound of n [n−1 <=d-1]/[n <=d] < d, which positively resolves a conjecture of Kuzmin and Warmuth relating to their unlabeled Peeling compression scheme and also leads to an improved one-inclusion mistake bound. The proof uses a new form of VC-invariant shifting and a group-theoretic symmetrization. Our second main result is an algebraic topological property of maximum classes of VC-dimension d as being d contractible simplicial complexes, extending the well-known characterization that d = 1 maximum classes are trees. We negatively resolve a minimum degree conjecture of Kuzmin and Warmuth—the second part to a conjectured proof of correctness for Peeling—that every class has one-inclusion minimum degree at most its VCdimension. Our final main result is a k-class analogue of the d/n mistake bound, replacing the VC-dimension by the Pollard pseudo-dimension and the one-inclusion strategy by its natural hypergraph generalization. This result improves on known PAC-based expected risk bounds by a factor of O(logn) and is shown to be optimal up to an O(logk) factor. The combinatorial technique of shifting takes a central role in understanding the one-inclusion (hyper)graph and is a running theme throughout.

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We present new expected risk bounds for binary and multiclass prediction, and resolve several recent conjectures on sample compressibility due to Kuzmin and Warmuth. By exploiting the combinatorial structure of concept class F, Haussler et al. achieved a VC(F)/n bound for the natural one-inclusion prediction strategy. The key step in their proof is a d=VC(F) bound on the graph density of a subgraph of the hypercube—one-inclusion graph. The first main result of this report is a density bound of n∙choose(n-1,≤d-1)/choose(n,≤d) < d, which positively resolves a conjecture of Kuzmin and Warmuth relating to their unlabeled Peeling compression scheme and also leads to an improved one-inclusion mistake bound. The proof uses a new form of VC-invariant shifting and a group-theoretic symmetrization. Our second main result is an algebraic topological property of maximum classes of VC-dimension d as being d-contractible simplicial complexes, extending the well-known characterization that d=1 maximum classes are trees. We negatively resolve a minimum degree conjecture of Kuzmin and Warmuth—the second part to a conjectured proof of correctness for Peeling—that every class has one-inclusion minimum degree at most its VC-dimension. Our final main result is a k-class analogue of the d/n mistake bound, replacing the VC-dimension by the Pollard pseudo-dimension and the one-inclusion strategy by its natural hypergraph generalization. This result improves on known PAC-based expected risk bounds by a factor of O(log n) and is shown to be optimal up to a O(log k) factor. The combinatorial technique of shifting takes a central role in understanding the one-inclusion (hyper)graph and is a running theme throughout

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Purpose: Hyperactive platelets contribute to the thrombotic response in humans, and exercise transiently increases platelet function. Caffeine is routinely used by athletes as an ergogenic aid, but the combined effect of exercise and caffeine on platelet function has not been investigated. Methods: Twelve healthy males were randomly assigned to one of four groups and undertook four experimental trials of a high-intensity aerobic interval training (AIT) bout or rest with ingestion of caffeine (3 mg·kg-1) or placebo. AIT was 8 × 5 min at approximately 75% peak power output (approximately 80% V?O2peak) and 1-min recovery (approximately 40% peak power output, approximately 50% V?O2peak) intervals. Blood/urine was collected before, 60, and 90 min after capsule ingestion and analyzed for platelet aggregation/activation. Results: AIT increased platelet reactivity to adenosine diphosphate (placebo 30.3%, caffeine 13.4%, P < 0.05) and collagen (placebo 10.8%, caffeine 5.1%, P < 0.05) compared with rest. Exercise placebo increased adenosine diphosphate-induced aggregation 90 min postingestion compared with baseline (40.5%, P < 0.05), but the increase when exercise was combined with caffeine was small (6.6%). During the resting caffeine protocol, collagen-induced aggregation was reduced (-4.3%, P < 0.05). AIT increased expression of platelet activation marker PAC-1 with exercise placebo (P < 0.05) but not when combined with caffeine. Conclusion: A single bout of AIT increases platelet function, but caffeine ingestion (3 mg·kg) does not exacerbate platelet function at rest or in response to AIT. Our results provide new information showing caffeine at a dose that can elicit ergogenic effects on performance has no detrimental effect on platelet function and may have the potential to attenuate increases in platelet activation and aggregation when undertaking strenuous exercise.

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Despite the prevalence of acute cough in children (<2 weeks duration), the burden to parents and families is largely unknown. The objectives of this study were to determine the parental burden of children’s acute cough, and to evaluate psychological and other infl uences on the reported burden of acute cough in children. Methods Parents of children with a current acute cough (<2 weeks) at enrolment completed 4 questionnaires (state trait anxiety inventory (STAI); short form health survey (SF-8); depression, anxiety and stress 21-item scale (DASS21); and our preliminary 48-item parent acute cough specifi c quality of life (PAC-QOL48) questionnaire). In PAC-QOL48, lower scores refl ect worse QOL. Results Median age of the 104 children enrolled was 2.63 (IQR 1.42, 4.79) years, 54 were boys. Median length of cough at enrolment was 3 (IQR 2, 5) days. Median total PAC-QOL48 score of parents enrolled at presentation to the emergency department (n = 70) was signifi cantly worse than of parents enrolled through the community (n = 24) (p < 0.01). More than half (n = 55) had sought medical assistance more than once for the current acute coughing illness. PAC-QOL48 score was signifi cantly negatively correlated to verbal category descriptive and visual analogue scale cough scores (Spearman r = −0.26, p = 0.05 and r = −0.46, p = 0.01 respectively) and DASS21 total score (r = −0.36, p = 0.01), but not to child’s age. Conclusions Consistent with data on chronic cough, stress was the predominant factor of parental burden. This study highlights the ongoing need for clinicians to be cognizant of parental worries and concerns when their children are coughing, and for further research into safe and effective therapies for acute cough in children.

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Objectives Current evidence to support non-medical prescribing is predominantly qualitative, with little evaluation of accuracy, safety and appropriateness. Our aim was to evaluate a new model of service for the Australia healthcare system, of inpatient medication prescribing by a pharmacist in an elective surgery preadmission clinic (PAC) against usual care, using an endorsed performance framework. Design Single centre, randomised controlled, two-arm trial. Setting Elective surgery PAC in a Brisbane-based tertiary hospital. Participants 400 adults scheduled for elective surgery were randomised to intervention or control. Intervention A pharmacist generated the inpatient medication chart to reflect the patient's regular medication, made a plan for medication perioperatively and prescribed venous thromboembolism (VTE) prophylaxis. In the control arm, the medication chart was generated by the Resident Medical Officers. Outcome measures Primary outcome was frequency of omissions and prescribing errors when compared against the medication history. The clinical significance of omissions was also analysed. Secondary outcome was appropriateness of VTE prophylaxis prescribing. Results There were significantly less unintended omissions of medications: 11 of 887 (1.2%) intervention orders compared with 383 of 1217 (31.5%) control (p<0.001). There were significantly less prescribing errors involving selection of drug, dose or frequency: 2 in 857 (0.2%) intervention orders compared with 51 in 807 (6.3%) control (p<0.001). Orders with at least one component of the prescription missing, incorrect or unclear occurred in 208 of 904 (23%) intervention orders and 445 of 1034 (43%) controls (p<0.001). VTE prophylaxis on admission to the ward was appropriate in 93% of intervention patients and 90% controls (p=0.29). Conclusions Medication charts in the intervention arm contained fewer clinically significant omissions, and prescribing errors, when compared with controls. There was no difference in appropriateness of VTE prophylaxis on admission between the two groups.

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Background Current evidence to support non-medical prescribing is predominantly qualitative, with little evaluation of appropriateness. This study aims to evaluate the appropriateness of prescribing, and significance of omissions, from a doctor pharmacist collaborative prescribing model in an elective surgery pre admission clinic (PAC). Method A modified version of the Medication Appropriate Index (MAI) was developed, piloted and subsequently used by an expert panel, comprised of a surgeon, anaesthetist, clinical pharmacologist, pharmacist, resident medical officer (RMO) and clinical nurse. The tool was used to rate the appropriateness of prescribing of medications, and the significance of omissions in a 5% sample (N=19) of the total cohort from a randomised, controlled two arm trial of doctor-pharmacist collaborative prescribing. Results When reviewer assessments were combined, 32 out of 294 (10.9%) medications assessed for appropriateness in the control arm were classed as inappropriate, compared to 13 of 266 (4.9%) in the intervention arm. Out of 89 regular medications in the control arm, 25 (28%) were omitted from the medication charts, compared to 1 out of 55 (2%) in the intervention arm (p<0.001, fishers exact) On average, 52% of omissions in the control arm were judged to have potential for patient harm or ward inconvenience. Conclusion For the appropriateness of prescribing, overall results were similar between arms, as judged by individual panel members. Medication charts in the control arm contained significantly more omissions than in the intervention arm, a number of which were rated by the panel members as having the potential for patient harm or ward inconvenience.

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Background Patient-relevant outcome measures are essential for high-quality clinical research, and quality-of-life (QoL) tools are the current standard. Currently, there is no validated children's acute cough-specific QoL questionnaire. Objective The objective of this study was to develop and validate the Parent-proxy Children's Acute Cough-specific QoL Questionnaire (PAC-QoL). Methods Using focus groups, a 48-item PAC-QoL questionnaire was developed and later reduced to 16 items by using the clinical impact method. Parents of children with a current acute cough (<2 weeks) at enrollment completed 2 validated cough score measures, the preliminary 48-item PAC-QoL, and 3 other questionnaires (the State Trait Anxiety Inventory [STAI], the Short-Form 8-item 24-hour recall Health Survey [SF-8], and the Depression, Anxiety, and Stress 21-item Scale [DASS21]). All measures were repeated on days 3 and 14. Results The median age of the 155 children enrolled was 2.3 years (interquartile range, 1.3-4.6). Median cough duration at enrollment was 3 days (interquartile range, 2-5). The reduced 16-item scale had high internal consistency (Cronbach α = 0.95). Evidence for repeatability and criterion validity was shown by significant correlations between the domains and total PAC-QoL scores and the SF-8 (r = −0.36 and −0.51), STAI (r = −0.27 and −0.39), and DASS21 (r = −0.32 and −0.41) scales on days 0 and 3, respectively. The final PAC-QoL questionnaire was sensitive to change over time, with changes significantly relating to changes in cough score measures (P < .001). Conclusion The 16-item PAC-QoL is a reliable and valid outcome measure that assesses QoL related to childhood acute cough at a given time point and reflects changes in acute cough-specific QoL over time.

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Background Pharmacist prescribing has been introduced in several countries and is a possible future role for pharmacy in Australia. Objective To assess whether patient satisfaction with the pharmacist as a prescriber, and patient experiences in two settings of collaborative doctor-pharmacist prescribing may be barriers to implementation of pharmacist prescribing. Design Surveys containing closed questions, and Likert scale responses, were completed in both settings to investigate patient satisfaction after each consultation. A further survey investigating attitudes towards pharmacist prescribing, after multiple consultations, was completed in the sexual health clinic. Setting and Participants A surgical pre-admission clinic (PAC) in a tertiary hospital and an outpatient sexual health clinic at a university hospital. Two hundred patients scheduled for elective surgery, and 17 patients diagnosed with HIV infection, respectively, recruited to the pharmacist prescribing arm of two collaborative doctor-pharmacist prescribing studies. Results Consultation satisfaction response rates in PAC and the sexual health clinic were 182/200 (91%) and 29/34 (85%), respectively. In the sexual health clinic, the attitudes towards pharmacist prescribing survey response rate were 14/17 (82%). Consultation satisfaction was high in both studies, most patients (98% and 97%, respectively) agreed they were satisfied with the consultation. In the sexual health clinic, all patients (14/14) agreed that they trusted the pharmacist’s ability to prescribe, care was as good as usual care, and they would recommend seeing a pharmacist prescriber to friends. Discussion and Conclusion Most of the patients had a high satisfaction with pharmacist prescriber consultations, and a positive outlook on the collaborative model of care in the sexual health clinic.