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Biomedical subjects

G A Wells

Publications and source records attributed to G A Wells.

At least 73 records · Page 4Linked to original sources

Does acute normovolemic hemodilution reduce perioperative allogeneic transfusion? A meta-analysis. The International Study of Perioperative Transfusion.

UNLABELLED: The objective of this study was to systematically review the literature and to statistically summarize the evidence evaluating acute normovolemic hemodilution (ANH). Prospective, randomized, controlled trials of ANH that reported either the proportion of patients exposed to allogeneic blood or the units of allogeneic blood transfused were included. All types and languages of publication were eligible. Of 1573 identified publications, 24 trials (containing a total of 1218 patients) were included in the meta-analysis. When all trials were pooled, ANH reduced the likelihood of exposure to allogeneic blood (odds ratio [OR] 0.31, 95% confidence interval [CI] 0.15, 0.62) and the total units of allogeneic blood transfused (weighted mean difference [WMD] -2.22 U, 95% CI -3.57, -0.86). However, there was marked heterogeneity of the results. In trials using a protocol to guide perioperative transfusion, ANH failed to reduce either the likelihood of transfusion (OR 0.64, 95% CI 0.31, 1.31) or the units administered (WMD -0.25 U, 95% CI -0.60, 0.10). Adverse events were incompletely reported. It is possible that biased experimental design is, in part, responsible for the reported efficacy of this technique. IMPLICATIONS: after a systematic literature review, 24 randomized trials examining the role of acute normovolemic hemodilution were identified, pooled, and summarized using statistical techniques. Many studies reported an impressive reduction in blood transfused. Closer examination suggests that these reductions in blood exposure may be due to flawed study design.

Blood Transfusion↗

The efficacy of folic acid and folinic acid in reducing methotrexate gastrointestinal toxicity in rheumatoid arthritis. A metaanalysis of randomized controlled trials.

OBJECTIVE: To assess the efficacy of folic acid and folinic acid in reducing the mucosal and gastrointestinal (GI) side effects of low dose methotrexate (MTX) in patients with rheumatoid arthritis (RA). METHODS: A systematic review was carried out using the methods recommended by the Cochrane Collaboration. We used MEDLINE and performed hand searches that included bibliographic references, Current Contents, abstracts of rheumatology meetings, and 4 rheumatology journals to select double blind randomized controlled trials (RCT) in which adult patients with RA were treated with low doses of MTX (< 20 mg/week), concurrently with folic or folinic acid. The quality of the RCT was assessed. The overall treatment effect across trials (reduction in toxicity) was estimated using a fixed effects model. Disease activity was evaluated using standardized mean differences to ensure comparability across outcome measures. Sensitivity analyses were conducted evaluating different doses and the quality of the trials. Costs per month in different countries were compared. RESULTS: Of 11 trials retrieved, 7 met inclusion criteria. The total sample included 307 patients, of which 147 were treated with folate supplementation, 67 patients with folic, and 80 with folinic acid. A 79% reduction in mucosal and GI side effects was observed for folic acid [OR = 0.21 (95% CI 0.10 to 0.44)]. For folinic acid, a clinically but nonstatistically significant reduction of 42% was found [OR = 0.58 (95% CI 0.29 to 1.16)]. No major differences were observed between low and high doses of folic or folinic acid. Hematologic side effects could not be analyzed, since details by patients of each event were not provided. No consistent differences in disease activity variables were observed when comparing placebo and folic acid or folinic acid at low doses; patients receiving high dose folinic acid had increased tender and swollen joint counts. Substantial differences in costs across countries were found; folinic acid was more expensive. CONCLUSION: Our results support the protective effect of folate supplementation in reducing MTX side effects related to the oral and GI systems.

Adult↗

Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries.

CONTEXT: The Ottawa Knee Rule is a previously validated clinical decision rule that was developed to allow physicians to be more selective and efficient in their use of plain radiography for patients with acute knee injuries. OBJECTIVE: To assess the impact on clinical practice of implementing the Ottawa Knee Rule. DESIGN: Controlled clinical trial with before-after and concurrent controls. SETTING: Emergency departments of 2 teaching and 2 community hospitals. PATIENTS: All 3907 consecutive eligible adults seen with acute knee injuries during two 12-month periods before and after the intervention. INTERVENTION: During the after period in the 2 intervention hospitals, the Ottawa Knee Rule was taught to all house staff and attending physicians who were encouraged to order knee radiography according to the rule. MAIN OUTCOME MEASURES: Referral for knee radiography, accuracy and reliability of the rule, mean time in emergency department, and mean charges. RESULTS: There was a relative reduction of 26.4% in the proportion of patients referred for knee radiography in the intervention group (77.6% vs 57.1 %; P<.001), but a relative reduction of only 1.3% in the control group (76.9% vs 75.9%; P=.60). These changes over time were significant when the intervention and control groups were compared (P<.001). The rule was found to have a sensitivity of 1.0 (95% confidence interval [CI], 0.94-1.0) for detecting 58 knee fractures. The K coefficient for interpretation of the rule was 0.91 (95% CI, 0.82-1.0). Compared with nonfracture patients who underwent radiography during the after-intervention period, those discharged without radiography spent less time in the emergency department (85.7 minutes vs 118.8 minutes) and incurred lower estimated total medical charges for physician visits and radiography (US $80 vs US $183). CONCLUSIONS: Implementation of the Ottawa Knee Rule led to a decrease in use of knee radiography without patient dissatisfaction or missed fractures and was associated with reduced waiting times and costs. Widespread use of the rule could lead to important health care savings without jeopardizing patient care.

Acute Disease↗

A cohort study to examine maternally-associated risk factors for bovine spongiform encephalopathy.

This long-term cohort study, initiated in July 1989, was designed to examine maternally-associated risk factors for bovine spongiform encephalopathy (BSE), forming part of the epidemiological research programme to assess the risks of non-feedborne transmission of BSE. In this study, the incidence of BSE in offspring of cows which developed clinical signs of BSE is compared with that in offspring, born in the same calving season and herd, of cows which had reached at least six years of age and had not developed BSE. All offspring were allowed to live to seven years of age. The results indicate a statistically significant risk difference between the two cohorts of 9.7 per cent and a relative risk of 3.2 for offspring of cows which developed clinical BSE. However, there is some evidence that this enhanced risk for offspring of BSE cases declined the later the offspring was born, but was increased the later the offspring was born in relation to the stage of the incubation period of the dam. The results presented cannot distinguish between a genetic component and true maternal transmission or a combination of both risks, but they do not indicate either that the BSE epidemic will be unduly prolonged or that the future incidence of BSE in Great Britain will increase significantly.

Animals↗

Variation in emergency department use of cervical spine radiography for alert, stable trauma patients.

OBJECTIVE: To, assess the emergency department use of cervical spine radiography for alert, stable adult trauma patients in terms of utilization, yield for injury and variation in practices among hospitals and physicians. DESIGN: Retrospective survey of health records. SETTING: Emergency departments of 6 teaching and 2 community hospitals in Ontario and British Columbia. PATIENTS: Consecutive alert, stable adult trauma patients seen with potential cervical spine injury between July 1, 1994, and June 30, 1995. MAIN OUTCOME MEASURES: Total number of eligible patients, referral for cervical spine radiography (overall, by hospital and by physician), presence of cervical spine injury, patient characteristics and hospitals associated with use of radiography. RESULTS: Of 6855 eligible patients, cervical spine radiography was ordered for 3979 (58.0%). Only 60 (0.9%) patients were found to have an acute cervical spine injury (fracture, dislocation or ligamentous instability); 98.5% of the radiographic films were negative for any significant abnormality. The demographic and clinical characteristics of the patients were similar across the 8 hospitals, and no cervical spine injuries were missed. Significant variation was found among the 8 hospitals in the rate of ordering radiography (p < 0.0001), from a low of 37.0% to a high of 72.5%. After possible differences in case severity and patient characteristics at each hospital were controlled for, logistic regression analysis revealed that 6 of the hospitals were significantly associated with the use of radiography. At 7 hospitals, there was significant variation in the rate of ordering radiography among the attending emergency physicians (p < 0.05), from a low of 15.6% to a high of 91.5%. CONCLUSIONS: Despite considerable variation among institutions and individual physicians in the ordering of cervical spine radiography for alert, stable trauma patients with similar characteristics, no cervical spine injuries were missed. The number of radiographic films showing signs of abnormality was extremely low at all hospitals. The findings suggest that cervical spine radiography could be used more efficiently, possibly with the help of a clinical decision rule.

Adolescent↗

Dexamethasone in salbutamol-treated inpatients with acute bronchiolitis: a randomized, controlled trial.

OBJECTIVE: To determine the clinical benefit of oral dexamethasone in children admitted to the hospital with bronchiolitis treated with nebulized salbutamol. METHODS: Randomized, double-blind, placebo-controlled trial in the inpatient wards of a pediatric tertiary care hospital. The participants, children aged 6 weeks to 15 months, admitted with first-time wheezing, were eligible if their oxygen saturation was less than 95% on admission to the hospital and their Respiratory Distress Assessment Instrument (RDAI) score was greater than 6. Patients were excluded if they had any one of the following: an underlying disease that might affect cardiopulmonary status, asthma, recent treatment with steroids (within 2 weeks), or any history of adverse reaction to steroids. Patients were randomly assigned to receive either orally administered dexamethasone with 0.5 mg/kg as the first dose and 0.3 mg/kg for the next 2 mornings, or an equal volume of an orally administered placebo with an identical appearance. All patients received nebulized salbutamol at 0.15 mg/kg every 4 hours for the first 24 hours. The primary outcome measure was the change from baseline in the RDAI score at 24 hours. Secondary outcome measures were oxygen saturation, respiratory rate, RDAI measurement twice daily for the first 4 days, and the length of hospitalization. RESULTS: At 24 hours the mean change (SD) from baseline in the RDAI score was 1.6 (2.3) in the placebo group (n = 28) and 1.4 (2.0) in the dexamethasone group (n = 33; p = 0.74). There were no significant differences between the two groups in change in oxygen saturation, respiratory rate, and RDAI score at any assessment period. The median length of stay (95% confidence interval) for the placebo group was 48 (42, 54) hours compared with 57 (38, 76) hours in the dexamethasone group (p = 0.19). CONCLUSIONS: Oral dexamethasone therapy does not affect the clinical course of children hospitalized with bronchiolitis and therefore cannot be recommended in this clinical situation.

Acute Disease↗

Variation in ED use of computed tomography for patients with minor head injury.

STUDY OBJECTIVE: To determine the frequency of utilization, yield for brain injury, incidence of missed injury, and variation in the use of computed tomography (CT) for ED patients with minor head injury. METHODS: This retrospective health records survey was conducted over a 12-month period in the EDs at seven Canadian teaching institutions. Included in this review were adult patients who sustained acute minor head injury, defined as witnessed loss of consciousness or amnesia and a Glasgow Coma Scale score of 13 or greater. Data were collected by research assistants who were trained to select cases and abstract data in a standardized fashion according to a resource manual. Subsequently, patient eligibility was reviewed by the study coordinator and principal investigator. RESULTS: Of the 1,699 patients seen, 521 (30.7%) were referred for CT, and 418 (79.8%) of these scans were negative for any type of brain injury. Overall, 105 (6.2%) of these patients sustained acute brain injury, including 9 (.5%) with an epidural hematoma Cochran's Q test for homogeneity demonstrated significant variation between the seven centers for rate of ordering CT (P < .0001), from a low of 15.9% to a high of 70.4%. All five cases of "missed" hematoma occurred at the institutions with the highest and third highest rates of CT use. After controlling for possible differences in case severity and patient characteristics at each hospital, logistic regression analysis revealed that five of seven hospitals were significantly associated with the use of CT (respected odds ratios [OR], .4, .5, .5, 3.2, and 4.7). Three of the centers (two with the highest ordering rates) showed significant heterogeneity in the ordering of CT among their attending staff physicians, from a low of 6.5% to a high of 80.0%. CONCLUSION: There was considerable variation among institutions and individual physicians in the ordering of CT for patients with minor head injury. Although emergency physicians were selective when ordering CT, the yield of radiography was very low at all hospitals. None of the cases of "missed" intracranial hematoma came from the lowest ordering institutions, indicating that patients may be managed safely with a selective approach to CT use. These findings suggest great potential for more standardized and efficient use of CT of the head, possibly through the use of a clinical decision rule.

Adolescent↗

Immediate postoperative enteral feeding results in impaired respiratory mechanics and decreased mobility.

OBJECTIVE: The authors set out to determine whether immediate enteral feeding minimizes early postoperative decreases in handgrip and respiratory muscle strength. SUMMARY BACKGROUND DATA: Muscle strength decreases considerably after major surgical procedures. Enteral feeding has been shown to restore strength rapidly in other clinical settings. METHODS: A randomized, controlled, nonblinded clinical trial was conducted in patients undergoing esophagectomy or pancreatoduodenectomy who received immediate postoperative enteral feeding via jejunostomy (fed, n = 13), or no enteral feeding during the first 6 postoperative days (unfed, n = 15). Handgrip strength, vital capacity, forced expiratory volume in one second (FEV1), and maximal inspiratory pressure (MIP) were measured before surgery and on postoperative days 2, 4, and 6. Fatigue and vigor were evaluated before surgery and on postoperative day 6. Mobility was assessed daily after surgery using a standardized descriptive scale. Postoperative urine biochemistry was evaluated in daily 24-hour collections. RESULTS: Postoperative vital capacity (p < 0.05) and FEV1 (p = 0.07) were consistently lower (18%-29%) in the fed group than in the unfed group, whereas grip strength and maximal inspiratory pressure were not significantly different. Postoperative mobility also was lower in the fed patients (p < 0.05) and tended to recover less rapidly (p = 0.07). Fatigue increased and vigor decreased after surgery (both p < or = 0.001), but changes were similar in the fed and unfed groups. Intensive care unit and postoperative hospital stay did not differ between groups. CONCLUSIONS: Immediate postoperative jejunal feeding was associated with impaired respiratory mechanics and postoperative mobility and did not influence the loss of muscle strength or the increase in fatigue, which occurred after major surgery. Immediate postoperative enteral feeding should not be routine in well-nourished patients at low risk of nutrition-related complications.

Age Factors↗

A prospective comparison of octylcyanoacrylate tissue adhesive and suture for the closure of head and neck incisions.

OBJECTIVE: To compare the tissue adhesive octylcyanoacrylate with subcuticular suture for the closure of head and neck incisions. DESIGN: A prospective comparison with a blinded assessment of cosmetic outcome. SUBJECTS: Fifty consecutive patients undergoing head and neck procedures at two University of Ottawa teaching hospitals. METHODS: Twenty-six patients underwent skin closure with monofilament suture and 24 were closed with tissue adhesive. At 4 to 6 weeks the incisions were evaluated with a validated wound scale. Photographs of the incisions were rated using a visual analogue scale by two facial-plastic otolaryngologists who were blinded to the method of skin closure. RESULTS: The adhesive provided faster skin closure (29.7 seconds vs 289.0 seconds, p < .0001), and there were no differences in complications between the two groups. The primary outcome measure was the cosmetic appearance of the incision at 4 to 6 weeks. Although the adhesive group scored higher on both cosmesis scales, the visual analogue scale (octylcyanoacrylate 58.7 mm vs suture 53.2 mm) and the wound evaluation scale (57% vs 50% optimal wound scores), there were no statistical or clinically significant differences on either scale. The two facial-plastic otolaryngologists had good intraobserver and interobserver agreement when rating the cosmetic outcomes (0.87 and 0.71 respectively). CONCLUSIONS: Octylcyanoacrylate was found to be an effective method of skin closure in clean head and neck incisions. The practical advantages of tissue adhesives are reviewed.

Adult↗

To wear or not to wear: current contact lens use in the Royal Canadian Mounted Police.

OBJECTIVE: The Canadian Ophthalmological Society was asked by the Royal Canadian Mounted Police (RCMP) and the Canadian Human Rights Commission to render an opinion on the acceptability of contact lenses as a reasonable accommodation to the uncorrected visual acuity standard. DESIGN: Survey by mailed questionnaire. SETTING: Canada. SUBJECTS: All RCMP general duty constables with a visual acuity code of V3, V4, V5 or V6 (n = 348) and a random sample of approximately 25% of the constables with an acuity code of V2 (n = 809). Of the 1040 questionnaires returned, 1037 were usable (final response rate 89.6%). Of the 1037 respondents 316 were in the V3 to V6 group and 721 were in the V2 group. OUTCOME MEASURES: Reported frequency of problems with spectacles or contact lenses, weighted according to sampling fraction. RESULTS: A total of 934 respondents indicated that they used some form of visual acuity correction while on duty; of the 934, 360 reported that they wore contact lenses at least some of the time. Approximately 75% of the spectacle wearers reported having to remove their spectacles because of fogging or rain. Although contact lens dislogement or fogging (21.2%) was less frequent than spectacle dislogement (59.2%), 35.4% of the contact lens wearers reported that they were unable to wear their lenses because of irritation on at least one occasion in the previous 2 years; the median length of time was 3.14 days. When the additional amount of time due to other causes is factored in, it is clear that contact lens users wear spectacles for substantial periods while on duty. CONCLUSIONS: Not only are RCMP general duty constables who usually wear contact lenses likely to have to wear spectacles at some time, but it is also possible that they will have to remove their spectacles and function in an uncorrected state in critical situations. Thus, altering the current standard to allow the use of contact lenses as a reasonable accommodation would not ensure effective and safe job performance.

Canada↗

Transmission dynamics and epidemiology of BSE in British cattle.

A comprehensive analysis of the bovine spongiform encephalopathy (BSE) epidemic in cattle in Great Britain assesses past, present and future patterns in the incidence of infection and disease, and allows a critical appraisal of different culling policies for eradication of the disease.

Age Factors↗

The Ontario trial of active compression-decompression cardiopulmonary resuscitation for in-hospital and prehospital cardiac arrest.

OBJECTIVE: To compare the impact of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) and standard CPR on the outcomes of in-hospital and prehospital victims of cardiac arrest. DESIGN: Randomized controlled trial with blinding of allocation using a sealed container. SETTINGS: (1) Emergency departments, wards, and intensive care units of 5 university hospitals and (2) all locations outside hospitals in 2 midsized cities. PATIENTS: A total of 1784 adults who had cardiac arrest. INTERVENTION: Patients received either standard or ACD CPR throughout resuscitation. MAIN OUTCOME MEASURES: Survival for 1 hour and to hospital discharge and the modified Mini-Mental State Examination (MMSE). RESULTS: All characteristics were similar in the standard and ACD CPR groups for the 773 in-hospital patients and the 1011 prehospital patients. For in-hospital patients, there were no significant differences between the standard (n = 368) and ACD (n = 405) CPR groups in survival for 1 hour (35.1% vs 34.6%; P = .89), in survival until hospital discharge (11.4% vs 10.4%; P = .64), or in the median MMSE score of survivors (37 in both groups). For patients who collapsed outside the hospital, there were also no significant differences between the standard (n = 510) and ACD (n = 501) CPR groups in survival for 1 hour (16.5% vs 18.2%; P = .48), in survival to hospital discharge (3.7% vs 4.6%; P = .49), or in the median MMSE score of survivors (35 in both groups). Exploration of clinically important subgroups failed to identify any patients who appeared to benefit from ACD CPR. CONCLUSIONS: ACD CPR did not improve survival or neurologic outcomes in any group of patients with cardiac arrest.

Adolescent↗

Prospective validation of a decision rule for the use of radiography in acute knee injuries.

OBJECTIVE: To validate a previously derived decision rule for the use of radiography in patients with acute knee injury. DESIGN: Prospectively administered survey. SETTING: Emergency departments of two university hospitals serving adults. PATIENTS: Convenience sample of 1096 of 1251 eligible adults with acute knee injuries; 124 patients were examined by two physicians. MAIN OUTCOME MEASURES: Attending emergency physicians assessed each patient for standardized clinical variables and determined the need for radiography according to the decision rule. Patients who did not have radiography underwent a structured telephone interview at day 14 to determine the possibility of a fracture. The rule was assessed for ability to correctly identify the criterion standard, fracture of the knee. An attempt was made to refine the rule by means of univariate and recursive partitioning analyses. RESULTS: The decision rule had a sensitivity of 1.0 (95% confidence interval [CI], 0.94 to 1.0) for identifying 63 clinically important fractures. Physicians correctly interpreted the rule in 96% of cases, and the k value for interpretation was 0.77 (95% CI, 0.65 to 0.89). The potential relative reduction in use of radiography was estimated to be 28%. The probability of fracture, if the decision rule were "negative," is estimated to be 0% (95% CI, 0% to 0.4%). Attempts to refine the rule led to a model with improved specificity but with an unacceptable loss of sensitivity. CONCLUSION: Prospective validation has shown this decision rule to be 100% sensitive for identifying fractures of the knee, to be reliable and acceptable, and to have the potential to allow physicians to reduce the use of radiography in patients with acute knee injury.

Adult↗

BSE in Great Britain: consistency of the neurohistopathological findings in two random annual samples of clinically suspect cases.

Two annual, random samples of clinically suspect cases of bovine spongiform encephalopathy (BSE) were taken in 1992-93 (year 1, 1500 cases) and 1993-94 (year 2, 1000 cases). From each sample, 100 positive cases were examined in detail to establish the severity of the vacuolation in 17 specific neuroanatomical locations. The resultant 'lesion profiles' were compared with the profile obtained from a similar sample of BSE-affected cattle from early in the epidemic (1987-89); the comparison showed that the distribution and severity of vacuolation in BSE has remained unchanged. The cases not confirmed as BSE on histological examination (172 in year 1 and 162 in year 2) were examined for evidence of any alternative neurohistological diagnosis. As in previous studies, the majority of these cases showed no significant lesions (61.6 and 61.7 per cent). The remainder consisted of bilateral focal spongiosis of unknown significance (26.7 and 21.0 per cent), inflammatory conditions (8.1 and 11.1 per cent) and a small number of cases with tumours, cerebrocortical necrosis or idiopathic brainstem neuronal chromatolysis. No evidence was found of any cases of BSE with an atypical distribution of lesions. These findings support the theory that the BSE epidemic is sustained by a single, stable strain of the BSE agent, and confirm that the existing statutory diagnostic criteria continue to be appropriate.

Animals↗

Factors influencing the emigration of physicians from Canada to the United States.

OBJECTIVE: To determine whether location of postgraduate medical training and other factors are associated with the emigration of physicians from Canada to the United States. DESIGN: Case-control study, physicians were surveyed with the use of a questionnaire mailed in May 1994 (with a reminder sent in September 1994), responses to which were accepted until Dec. 31, 1994. PARTICIPANTS: Physicians randomly selected from the CMA database, 4000 with addresses in Canada and 4000 with current addresses in the United States and previous addresses in Canada. OUTCOME MEASURES: Sex, age, location of undergraduate and postgraduate medical training, qualifications, practice location, opinions concerning residence decisions, current satisfaction and plans. RESULTS: The overall response rate was 49.6% (50.0% among physicians in the United States and 49.2% among those in Canada). Age and sex distributions were similar among the 8000 questionnaire recipients and the nearly 4000 respondents. Physicians living in the United States were more likely to be older (mean 53.2 v. 49.6 years of age), male (87% v. 75%) and specialists (79% v. 52%) than those practising in Canada. Postgraduate training in the United States was associated with subsequent emigration (odds ratio 9.2, 95% confidence interval 7.8 to 10.7). However, in rating the importance of nine factors in the decision to emigrate or remain in Canada, there was no significant difference between the two groups in the rating assigned to location of postgraduate training. Professional factors rated most important by most physicians in both groups were professional/clinical autonomy, availability of medical facilities and job availability. Remuneration was considered an equally important factor by those in Canada and in the United States. Six of seven personal/family factors were rated as more important to their choice of practice location by respondents in Canada than by those in the United States. Current satisfaction was significantly higher among respondents in the United States. Most physicians in each group planned to continue practising at their current location. Of Canadian respondents, 22% indicated that they were more likely to move to the United States than they were a year beforehand, whereas 4% of US respondents indicated that they were more likely to return to Canada. CONCLUSIONS: Factors affecting the decision to move to the United States or remain in Canada can be categorized as "push" factors (e.g., government involvement) and "pull" factors (e.g., better geographic climate in the US). Factors can also be categorized by whether they are amenable to change (e.g., availability of medical facilities) or cannot be managed (e.g., proximity of relatives). An understanding of the reasons why physicians immigrate to the United States or remain in Canada is essential to planning physician resources nationally.

Adult↗