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Biomedical subjects

Alan Tinmouth

Publications and source records attributed to Alan Tinmouth.

13 recordsLinked to original sources
PubMed2006

Red blood cell transfusion practices amongst Canadian anesthesiologists: a survey.

PURPOSE: To assess red blood cell transfusion practices among Canadian anesthesiologists. METHODS: A survey depicting three realistic clinical scenarios of elective surgical procedures with different risks of bleeding was administered to all Canadian practicing members (n = 2,100) of the Canadian Anesthesiologists' Society. Respondents were requested to choose hemoglobin thresholds for which they would transfuse red blood cells under various conditions within each scenario. RESULTS: We obtained a response rate of 47% (719/1,512). Transfusion thresholds differed significantly between baseline scenarios. A threshold above 70 g x L(-1) was chosen by 48% of respondents in the general surgery scenario compared to 56% in the orthopedic surgery scenario and 79% in the vascular surgery scenario (P < 0.001). A history of coronary artery disease was associated with a transfusion threshold >or= 100 g x L(-1) in a significant proportion of respondents ranging from 20% in the orthopedic surgery scenario to 31% in the general surgery scenario and to 49% in the vascular surgery scenario (P < 0.001). Conversely, changing the patient's age from 60 to 20 yr resulted in the adoption of a transfusion threshold 30% of respondents in two scenarios (P < 0.001). The year of respondent graduation was strongly associated with these findings. CONCLUSION: There was significant variation in transfusion practices among Canadian anesthesiologists. The type of surgical procedure, patient's age and a history of coronary artery disease influenced reported transfusion threshold. Practice variation in specific subgroups would support the need for further research to identify optimal transfusion thresholds.

Anesthesiology↗
PubMed2005

Reducing the amount of blood transfused: a systematic review of behavioral interventions to change physicians' transfusion practices.

BACKGROUND: Transfusion services have used various techniques to reduce blood product utilization. Given the potential adverse effects of transfusions and the resources consumed in implementing strategies to reduce transfusions, there is a need to understand their effectiveness. Therefore, we performed a systematic review of the literature to examine the effectiveness of behavioral interventions to reduce blood product utilization. METHODS: We identified all relevant articles through the use of electronic searches of MEDLINE and EMBASE, as well as hand searches of review articles and personal files. The electronic searches included articles published between January 1966 and May 2003. The searches included the terms blood transfusion, plasma exchange, guidelines, education, practice patterns, and professional practice. The outcomes of interest were the number of units transfused and the proportion of patients who received transfusions. RESULTS: Nineteen studies examining the effectiveness of single (guidelines, prospective audits, retrospective audits, and reminders) or multifaceted interventions in reducing red blood cell, platelet, plasma, cryoprecipitate, and albumin transfusions met the inclusion criteria. Eighteen studies demonstrated a relative reduction in the number of units given (range, 9%-77%) or the proportion of patients receiving transfusions (range, 17%-79%). The reported reductions were qualitatively similar for the different blood products studied. No particular intervention or combination of interventions appeared more effective in reducing utilization. CONCLUSIONS: Behavioral interventions, including simple interventions, appear to be effective in changing physician transfusion practices and reducing blood utilization. Appropriately designed clinical trials are still needed to determine the relative effectiveness of different interventions to change practices.

Behavior↗
PubMed2005

Use of intravenous immunoglobulin for treatment of neurologic conditions: a systematic review.

BACKGROUND: Given the increasing use of intravenous immunoglobulin (IVIG) for various neurologic conditions and uncertainty pertaining to its benefits and harms, a systematic review was conducted of randomized controlled trials (RCTs) evaluating IVIG for all neurologic indications for which there was at least one published trial. STUDY DESIGN AND METHODS: For this systematic review, a systematic search strategy was applied to MEDLINE (1966-June 2003) and the Cochrane Register of Controlled Trials (June 2003) to identify potentially eligible RCTs comparing IVIG to placebo or an active control. All dosage regimens were considered. Abstracts were excluded, and no restriction was placed on language of publication. Two investigators independently performed data extraction with a standardized form. Measures of effect were calculated for each trial independently, and studies were pooled based on clinical and methodologic judgment as to its appropriateness. Where pooling of trials was inappropriate, a qualitative discussion of findings is provided. RESULTS AND CONCLUSIONS: Thirty-seven trials representing 14 conditions were identified. IVIG is more effective than placebo for treatment of relapsing-remitting multiple sclerosis and idiopathic chronic inflammatory demyelinating polyneuropathy. There is also potential benefit for treatment of multifocal motor neuropathy, myasthenia gravis, dermatomyositis, stiff-person syndrome, and Lambert-Eaton myasthenic syndrome. There was insufficient evidence to determine whether IVIG therapy was more effective than plasma exchange for Guillain-Barré syndrome. There was also insufficient evidence regarding paraprotein-associated polyneuropathy. No evidence of benefit was observed for secondary progressive multiple sclerosis or inclusion body myositis.

Adrenal Cortex Hormones↗
PubMed2004

Does a perception of increased blood safety mean increased blood transfusion? An assessment of the risk compensation theory in Canada.

BACKGROUND: The risk compensation theory is a widely used concept in transport economics to analyze driver risk behaviour. This article explores the feasibility of applying the theory in blood transfusion to raise important questions regarding the increased blood safety measures and their possible effects on blood usage (e.g., the appropriateness in transfusion). Further, it presents the findings of a pilot survey of physicians in Canada. DISCUSSION: While studies have attempted to define transfusion appropriateness, this article argues that if the risk compensation theory holds true for transfusion practice, physicians may actually be transfusing more. This may increase the possibility of contracting other unknown risks, such as the variant Creutzfeldt-Jakob Disease (vCJD), as well as increasing the risk of non-infectious transfusion risks, such as transfusion reactions. SUMMARY: A much larger study involving psychosocial assessment of physician decision making process to fully assess physician behaviour within the context of risk compensation theory and transfusion practice in Canada is needed to further explore this area.

Attitude of Health Personnel↗
PubMed2004

Transfusion of leukoreduced red blood cells may decrease postoperative infections: two meta-analyses of randomized controlled trials.

PURPOSE: To evaluate the efficacy and effectiveness of red blood cell leukoreduction in reducing postoperative infection, mortality and cancer recurrence, two meta-analyses of randomized controlled trials (RCTs) were conducted. METHODS: A systematic search of the scientific literature was conducted. The pooled relative risk ratio (RR) of developing an adverse postoperative outcome with either leukoreduced or non-leukoreduced blood was calculated using a random effects model. To better estimate the efficacy of leukoreduction, a second analysis of transfused patients only was conducted. RESULTS: Ten RCTs met inclusion criteria and eight provided separate data for patients randomized and transfused. The mean percentage of patients randomized but not transfused was 34%. For postoperative infection, the overall pooled RR was 0.76 [(95% confidence interval (CI): 0.54-1.08] for the "all patients randomized" analysis. For the "only patients transfused" analysis, the pooled RR became clinically and statistically significant (RR = 0.60 (95% CI: 0.38-0.93). For mortality, the pooled RR for the "all patients randomized" analysis was 0.71 (95% CI: 0.45-1.13) and 0.61 (95% CI: 0.36-1.04) for the "only patients transfused" analysis. When analyzing either all patients randomized or all patients transfused, there was no statistically significant difference in cancer recurrence rates (one study only). CONCLUSION: We demonstrated that patients who were transfused leukoreduced red blood cells might benefit from a decrease in postoperative infections. A decrease in mortality may have been realized if more patients had been enrolled in the various randomized trials. Including all patients randomized, regardless of whether or not they were actually transfused diluted the observed clinical benefit of leukoreduction.

Blood Transfusion↗
PubMed2004

Clinical consequences of anemia and red cell transfusion in the critically ill.

Despite the frequent use of red cell transfusions, only one large randomized trial has examined red cell administration perioperative and in the critical care setting. However, the TRICC Trial does not provide sufficient evidence to determine optimal transfusion practice in postoperative care, in critically ill children, or in patients with a myocardial infarction or acute coronary syndromes. In addition, most transfusion practice guidelines published before the completion of the TRICC Trial are now dated and need to have expert opinion informed by solid evidence in diverse clinical settings. In the next several years,several randomized trials will provide additional evidence in support of bedside decision-making. For example, two transfusion studies will be evaluating transfusion triggers, including one in premature infants and the other in critically ill children. At this juncture, high-quality clinical evidence is not yet available for many decisions related to red cell transfusions. We anticipate that risks and benefits of red cells and alternatives will be elucidated in the coming years.

Acute Disease↗
PubMed2004

Low-dose prophylactic platelet transfusions in recipients of an autologous peripheral blood progenitor cell transplant and patients with acute leukemia: a randomized controlled trial with a sequential Bayesian design.

BACKGROUND: Prophylactic platelet (PLT) transfusions are standard treatment for patients receiving high-dose chemotherapy, but the optimal dose is not known. A randomized controlled trial was undertaken to examine the effectiveness of low-dose PLT transfusions and to determine the need for further studies. STUDY DESIGN AND METHODS: Patients (n = 111) with acute leukemia or undergoing autologous peripheral blood progenitor cell (PBPC) transplantation were randomly assigned to receive low-dose (3 PLT units) or standard-dose (5 PLT units) prophylactic PLT transfusions and were monitored daily for bleeding. Using a sequential Bayesian design, the difference in major bleeding events was determined. RESULTS: The percentage of patients with major bleeding events was 10.7 percent (95% credible region, 5.1%-21.2%) in the low-dose PLT group and 7.3 percent (95% credible region, 2.9%-17.2%) in the standard-dose PLT group. The two additional events in the low-dose group occurred when the PLT count exceeded 100 x 10(9) per L. There is an 89 percent probability that the absolute increase in major bleeds is less than 10 percent with low-dose PLT transfusions. The number of minor bleeding events was higher in the standard-dose group. Patients receiving low-dose PLT transfusions received 25 percent fewer PLT units. There was an 89 percent probability that low-dose transfusions reduced PLT utilization in patients with acute leukemia and a 60 percent probability in patients undergoing PBPC transplantation. CONCLUSION: Low-dose PLT transfusions appear to be safe and effective and reduce PLT utilization. They should be further evaluated in clinical trials designed to evaluate equivalency.

Acute Disease↗
PubMed2004

The societal unit cost of allogenic red blood cells and red blood cell transfusion in Canada.

BACKGROUND: There is a dearth of information about the cost of allogenic red blood cells (RBCs) and RBC transfusion in Canada in the aftermath of the Canadian blood system reorganization and the introduction of various safety measures. The unit cost of allogenic RBCs and RBC transfusion in Canada in 1994 was estimated at 152.17 US dollars. The objective of this study was to determine the unit cost of allogenic RBC transfusion in Canada from a societal perspective. STUDY DESIGN AND METHODS: A cost-structure analysis using the cost information from 2001 through 2002 was used. Costs of blood collection, production, distribution, delivery (hospital transfusion service processing and patient administration), transfusion reaction management, and opportunity cost of donor's time were included in the analysis. Canadian Blood Services and Héma-Québec supplied the data for collection, production, and distribution stages. Delivery and transfusion reaction costs were collected from eight hospitals across six Canadian provinces. In-patient costs were assessed for the intensive care unit, emergency, general medicine ward, and operating room. RESULTS: The aggregate mean societal unit cost of RBCs transfused on an inpatient basis in 2002 was 264.81 US dollars (95% confidence interval [CI], 256.29 dollars-275.65 dollars). The mean cost of blood collection, production, and distribution was 202.74 US dollars (95% CI, 199.63 dollars-204.31 dollars), the mean opportunity cost of donor time was 18.21 US dollars (95% CI, 17.11 dollars-21.63 dollars), the mean cost of hospital transfusion service processing was 16.65 US dollars (95% CI, 13.50 dollars-19.79 dollars), of RBC transfusion was 26.92 US dollars (95% CI, 25.33 dollars-28.52 dollars), and of transfusion reaction management was 0.29 US dollars(95% CI, 0.22 dollars-0.36 dollars). There were substantial variations in hospital transfusion service processing and RBC transfusion costs across hospitals. CONCLUSION: The societal unit cost of RBC transfusion has doubled since 1994 to 1995. Further increases in unit costs would be expected as additional safety measures are introduced. This will have important financial implications for treating patient populations that require a high level of RBC transfusions.

Blood Banks↗
PubMedDate not supplied

Transfusion rates vary significantly amongst Canadian medical centres.

PURPOSE: To document variation of transfusion practice following repair of hip fracture or cardiac surgery, as well as those requiring intensive care following a surgical intervention or multiple trauma (high risk patients). METHODS: We documented rates of allogeneic red cell transfusion in 41,568 patients admitted to 11 hospitals across Canada between August 1998 and August 2000 as part of a retrospective observational cohort study. In the subgroup of 7,552 patients receiving red cells, we also compared mean nadir hemoglobin concentrations from centre to centre. RESULTS: The overall rate of red cell transfusion was 38.7%, and ranged from 23.8% to 51.9% across centres among the 41,568 perioperative and critically ill patients. Women were more likely to be transfused (43.7% vs 35.3%, P < 0.0001), with higher rates of transfusion in eight of 11 centres. Compared to a chosen reference hospital having a crude transfusion rate near the median, the adjusted odds of transfusion ranged from 0.44 to 1.53 overall, from 0.42 to 1.22 in patients undergoing a hip fracture repair, from 0.72 to 3.17 in cardiac surgical patients undergoing cardiac surgery, and from 0.27 to 1.11 in critically ill and trauma patients. In the 7,552 transfused patients, the mean adjusted nadir hemoglobin was 74.0 +/- 4.83 g x L(-1) overall, and ranged from 66.9 +/- 1.7 g x L(-1) to 84.5 +/- 1.6 g x L(-1) across centres. Similar differences among centres were observed amongst hip fracture patients (71.2 +/- 2.9 g x L(-1) to 82.8 +/- 1.7 g x L(-1)), cardiac surgical patients (65.7 +/- 1.1 g x L(-1) to 77.3 +/- 1.0 g x L(-1)) and critically ill and trauma patients (66.1 +/- 3.04 g x L(-1) to 87.5 +/- 2.5 g x L(-1)). CONCLUSION: We noted significant differences in the rates of red cell transfusion and nadir hemoglobin concentrations in various surgical and critical care settings.

Adolescent↗