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Biomedical subjects

D J Cook

Publications and source records attributed to D J Cook.

At least 181 records · Page 10Linked to original sources
PubMed1996

Discrimination and abuse in internal medicine residency. The Internal Medicine Program Directors of Canada.

OBJECTIVE: To survey the extent to which internal medicine housestaff experience abuse and discrimination in their training. DESIGN: Through a literature review and resident focus groups, we developed a self-administered questionnaire. In this cross-sectional survey, respondents were asked to record the frequency with which they experienced and witnessed different types of abuse and discrimination during residency training, using a 7-point Likert scale. PARTICIPANTS: Internal medicine housestaff in Canada. MEASUREMENTS AND MAIN RESULTS: Of 543 residents in 13 programs participating (84% response rate), 35% were female. Psychological abuse, as reported by attending physicians (68%), patients (79%), and nurses or other health workers (77%), was widespread. Female residents experienced gender discrimination by attending physicians (70%), patients (88%), and nurses (71%); rates for males were 23%, 38%, and 35%, respectively. Females reported being sexually harassed more often than males, by attending physicians (35% vs 4%, p < .01), peers (30% vs 6%, p < .01), and patients (56% vs 18%, p < .01). Physical assault by patients was experienced by 40% of residents. Half of the residents surveyed reported racial discrimination and homophobic remarks in the workplace, perpetrated by all groups of health professionals. CONCLUSIONS: Psychological abuse, gender discrimination, sexual harassment, physical abuse, homophobia, and racial discrimination are prevalent problems during residency training. Housestaff, medical educators, allied health workers, and the public need to work together to address these problems in the training environment.

Adult↗
PubMed1996

Does successful bridging with the implantable left ventricular assist device affect cardiac transplantation outcome?

OBJECTIVES: We sought to determine whether cardiac transplant recipients who required a bridge to transplantation with an implantable left ventricular assist device had a different outcome than patients who underwent transplantation without such a bridge. METHODS: A retrospective study of 256 cardiac transplants from 1992 to 1996 included 53 patients who received the HeartMate left ventricular assist device and 203 patients who had no left ventricular assist device support. RESULTS: Left ventricular assist device transplants increased from 8% of all transplants in 1992 (n = 63) to 32% in 1995 (n = 65) and 43% in 1996 (n = 14 year to date). Patients with and without left ventricular assist device had similar age and sex distributions. Left ventricular assist device recipients were larger (body surface area 1.96 vs 1.86 m2, p = 0.004). They were more likely to have ischemic cardiomyopathy (70% vs 45%, p = 0.001) and type O blood group (51% vs 34%, p = 0.06). All patients with left ventricular assist device and 42% of those without had undergone previous cardiac operations by the time of transplantation (mean number per patient 1.5 vs 0.3, p < 0.001). More patients in the left ventricular assist device group had anti-HLA antibodies before transplantation (T-cell panel reactive antibody level > 10% in 66% of left ventricular assist device group vs 15% of control group, p < 0.0001). Waiting time was longer for the left ventricular assist device than for patients in status I without a left ventricular assist device (median 88 vs 37 days, p = 0.002). There was no difference in length of posttransplantation hospital stay (median 15 days for each) or operative mortality (3.8% vs 4.4%). Mean follow-up averaged 22 months. No significant difference was found in Kaplan-Meier survival estimates. One-year survival was 94% in the left ventricular assist device group and 88% in the control group (difference not significant). Comparison of posttransplantation events showed no significant difference in actuarial rates of cytomegalovirus infection (20% vs 17%) or vascular rejection (15% vs 12%) at 1 year of follow-up. Similar percentages of patients were free from cellular rejection at 1 year of follow-up (12% vs 22%, p = 0.36). CONCLUSIONS: Left ventricular assist device support intensified the donor shortage by including recipients who otherwise would not have survived to transplantation. Bridging affected transplant demographics, favoring patients who are larger, have ischemic cardiomyopathy, have had multiple blood transfusions and complex cardiac operations, and are HLA sensitized. Successfully bridged patients wait longer for a transplant than do UNOS status I patients without such a bridge, but they have similar posttransplantation hospital stay, operative mortality, and survival to those of patients not requiring left ventricular assist device support.

Adult↗
PubMed1996

The relationship between cerebral blood flow and transcranial Doppler blood flow velocity during hypothermic cardiopulmonary bypass in adults.

A noninvasive, simple, and continuous method to assess cerebral perfusion during cardiopulmonary bypass (CPB) could help prevent cerebral ischemia. Transcranial Doppler sonography (TCD) allows a noninvasive, on-line measurement of blood flow velocity in cerebral arteries. The correlation of TCD-estimated and actual cerebral blood flow (CBF) has not been well studied during CPB. We determined the correlation of middle cerebral artery (MCA) mean velocity and CBF determined by the Kety-Schmidt method during nonbypass and two hypothermic bypass flow conditions. Sixteen patients undergoing hypothermic (27 degrees C) CPB for coronary artery bypass grafting and/or valve replacement surgery were enrolled in the study. We were able to determine MCA velocity in only 12 patients. We determined CBF and MCA velocity in each patient during four 15-min study periods: 1) prebypass after sternotomy before aortic cannulation; 2) hypothermic (27 degrees C) CPB with 1.2 L.min-1.m-2 pump flow; 3) hypothermic CPB with 2.4 L.min-1.m-2 pump flow, and 4) 30 min after weaning from CPB. There was no difference in the mean arterial pressure between the two CPB pump blood flows. The pooled change in MCA velocity and CBF as percentage of baseline (prebypass) for all patients and at all time points had a correlation of 0.33 (r). A decrease or increase in MCA velocity did not necessarily indicate a corresponding decrease or increase in CBF. This technology may be of limited usefulness during the circulatory condition of hypothermic, nonpulsatile CPB.

Aged↗
PubMed1996

Evidence based critical care medicine; what is it and what can it do for us? Evidence Based Medicine in Critical Care Group.

OBJECTIVE: To describe the philosophy and approach to patient care called evidence based medicine, and to highlight how it can enhance the practice of intensive care. DATA SOURCES: We searched MEDLINE, reference lists, and our personal files to identify relevant literature. STUDY SELECTION: Articles on intensive care practice, critical appraisal, clinical research, and healthcare delivery were selected for discussion. DATA SYNTHESIS: We summarize the rationale for evidence based medicine, its applications and future developments, and suggest several methods for intensivists to use evidence based medicine in their practice and teaching. CONCLUSIONS: Evidence based medicine can complement other foundation disciplines in intensive care. This is the first article in a series entitled "Evidence Based Critical Care Medicine" which will demonstrate how this approach can be used at the bedside.

Clinical Competence↗
PubMed1996

Maximizing oxygen delivery in critically ill patients: a methodologic appraisal of the evidence.

OBJECTIVE: To systemically review the effect of interventions designed to achieve supraphysiologic values of cardiac index, oxygen delivery (DO2), and oxygen consumption (VO2) in critically ill patients. DATA SOURCES: Computerized bibliographic search of published research, citation review of relevant articles, and contact with primary investigators. STUDY SELECTION: We included all randomized clinical trials of adult intensive care unit (ICU) patients that evaluated interventions (fluids, inotropes, and vasoactive drugs) designed to achieve supraphysiologic values of cardiac index, DO2, and/or VO2. Independent review of 64 articles identified seven relevant studies of 1,016 patients. DATA EXTRACTION: We abstracted data on the population, interventions, outcomes, and methodologic quality of the studies by duplicate independent review. Agreement was high (weighed kappa 0.73); differences were resolved by consensus. DATA SYNTHESIS: Targeting therapy to achieve supraphysiologic end points in critically ill patients is associated with a nonstatistically significant trend toward decreased mortality rates (relative risk 0.86, 95% confidence intervals 0.62 to 1.20). For the two studies in which supraphysiologic goals were initiated preoperatively, the relative risk was 0.20 (95% confidence intervals 0.07 to 0.55). This value differed significantly from the combined estimate of the remaining studies, in which the intervention was started after ICU admission (relative risk 0.98, 95% confidence intervals 0.79 to 1.22; p<.01). However, there are several methodologic problems with the primary studies. In no trials were caregivers or outcome assessors blinded to treatment allocation. Only three of seven trials analyzed patients according to the group to which they were allocated. None adequately controlled for cointerventions, and there was considerable crossover between groups (patients in the control group achieved the goals of the intervention group and vice versa). CONCLUSIONS: Interventions designed to achieve supraphysiologic goals of cardiac index, DO2, and VO2 did not significantly reduce mortality rates in all critically ill patients. However, there may be a benefit in those patients in which the therapy is initiated preoperatively. Methodologic limitations weaken the inferences that can be drawn from these studies and preclude any evidence-based clinical recommendations.

Adult↗
PubMed1996

Economic evaluations in the critical care literature: do they help us improve the efficiency of our unit?

OBJECTIVE: To determine the extent to which economic evaluations published in the critical care literature provide information that can help us to improve the efficiency of our unit. DATA SOURCES: We searched computerized bibliographic databases and manually searched key critical care journals to retrieve all economic evaluations. STUDY SELECTION: We included economic evaluations that dealt with clinical problems relevant to the practice of adult critical care and that compared competing healthcare interventions. DATA ABSTRACTION: Included articles were further evaluated using criteria for minimal methodologic soundness, adopted from the literature, and criteria that we developed to assess the generalizability of results to our clinical setting. DATA SYNTHESIS: We screened 4,167 papers manually and > 450 abstracts and titles in our computer search. One hundred fifty-one papers were retrieved for further evaluation; 29 papers met our inclusion criteria. Of these 29 papers, only 14 (48%) adequately described competing healthcare interventions, 17 (59%) provided sufficient evidence of clinical efficacy, six (21%) identified, measured, and valuated costs appropriately, and three (10%) performed a sensitivity analysis. None of the papers met all four of these criteria for a minimum level of methodologic soundness. Four (14%) of 29 studies which adequately dealt with issues of cost and efficacy were evaluated using our generalizability criteria. Different costing methods precluded the application of the results of three of the four studies to our intensive care unit. CONCLUSIONS: In the critical care literature, very little useful economic information exists to help decision-makers maximize efficiency in their own setting.

Adult↗
PubMed1996

How to keep up with the critical care literature and avoid being buried alive.

OBJECTIVE: To provide practical suggestions for accessing, utilizing, and storing the rapidly expanding literature on critical care. DATA SOURCES: Original research on information sources for clinicians and techniques for keeping up with the literature, found through bibliographic searches, our personal files, and consultation with critical care colleagues. DATA SYNTHESIS: Suggestions for keeping up with the critical care literature include: 1) focus the clinical question; 2) locate literature using bibliographic databases; 3) use original journal articles; 4) use systematic reviews with confidence; 5) use text-books with caution; 6) read the preappraised literature; 7) abandon advertisements; 8) throw away the throwaways; 9) teach yourself critical appraisal; 10) be wary of overinterpretation of substitute end points; 11) teach yourself basic clinical statistics; 12) engage in effective browsing; 13) store useful articles; 14) invest in informatics; and 15) implement evidence-based practice guidelines. CONCLUSION: Efficient access, appraisal, and application of the literature on intensive care are basic skills for intensivists, who have adopted a variety of resourceful and pragmatic methods for "keeping up."

Critical Care↗
PubMed1996

Ultrasound guidance for placement of central venous catheters: a meta-analysis of the literature.

OBJECTIVE: To evaluate the effect of real-time ultrasound guidance using a regular or Doppler ultrasound technique for placement of central venous catheters. DATA SOURCES: We searched for published and unpublished research using MEDLINE, citation review of relevant primary and review articles, conference abstracts, personal files, and contact with expert informants. STUDY SELECTION: From a pool of 208 randomized, controlled trials of venous and arterial catheter management, eight published randomized, controlled trials were identified. DATA EXTRACTION: In duplicate, independently, we abstracted data on the population, intervention, outcome, and methodologic quality. DATA SYNTHESIS: Ultrasound guidance significantly decreases internal jugular and subclavian catheter placement failure (relative risk 0.32; 95% confidence interval 0.18 to 0.55), decreases complications during catheter placement (relative risk 0.22; 95% confidence interval 0.10 to 0.45), and decreases the need for multiple catheter placement attempts (relative risk 0.60; 95% confidence interval 0.45 to 0.79) when compared with the standard landmark placement technique. CONCLUSIONS: When used for vessel location and catheter placement real-time, ultrasound guidance or Doppler ultrasound guidance improves success rates and decreases the complications associated with internal jugular and subclavian venous catheter placement.

Catheterization, Central Venous↗
PubMed1996

Introducing Critical Appraisal to studies of animal models investigating novel therapies in sepsis.

OBJECTIVES: To discuss theoretical and practical aspects relating to the design of animal studies investigating the efficacy of novel therapeutic agents for the treatment of sepsis, and to make explicit the process whereby these studies can be evaluated for the purpose of designing clinical trials in humans. DATA SOURCES: Relevant articles from the pertinent literature were reviewed. STUDY SELECTION: Studies relevant to an evidence-based assessment of clinical studies on therapeutic efficacy, and studies relevant to the design of animal models of sepsis were selected. DATA EXTRACTION: Concepts relevant to an evidence-based assessment of the animal literature were extracted. DATA SYNTHESIS: Articles were reviewed and an evidence-based framework for the assessment of animal studies was developed. In this process, we discuss the steps that are necessary to assess the internal validity of an individual study and review topics relevant to the application of animal data to the design of clinical trials. CONCLUSIONS: The success of clinical trials of sepsis therapies is predicated on the generation and interpretation of sound preclinical data. In this review, we have attempted to outline an evidence-based approach to the assessment of preclinical animal studies evaluating novel therapeutic interventions in sepsis.

Animals↗
PubMed1996

Cisapride improves gastric emptying in mechanically ventilated, critically ill patients. A randomized, double-blind trial.

We conducted a randomized, double-blind, placebo-controlled trial in mechanically ventilated intensive care unit (ICU) patients to evaluate the effect of cisapride on gastric emptying using an acetaminophen absorption model. We enrolled 72 patients expected to remain in the ICU for more than 48 h; 39% were female; the average age was 54.0 +/- 19.1 yr; 47% were postoperative, 83% were receiving narcotics, and the mean simplified acute physiology score (SAPS) was 9.5 +/- 3.0. Within 72 h of admission to ICU, 1.6 g of acetaminophen suspension was administered via a nasogastric tube into the stomach (Day 1). Blood samples were drawn at baseline, 30, 60, 90, 120, and 180 min for measurement of plasma acetaminophen levels. The following morning (Day 2), patients were randomized to receive 20 mg of cisapride or placebo and gastric emptying was again assessed. The difference (Day 2-Day 1) in the maximal plasma concentration was 49.1 mumol/L in the cisapride groups compared with 12.3 mumol/L in the placebo group (p = 0.005) and the time to reach maximal concentration was significantly shorter in the cisapride group (-40.8 min versus -4.2 min, p = 0.02). The difference in area under the time-acetaminophen concentration curve was also greater in the patients receiving cisapride (5,534 versus 2,832, p = 0.09). We conclude that cisapride enhances gastric emptying in critically ill patients. Studies to examine the effect of cisapride on tolerance to enteral nutrition, infectious morbidity, and other clinically important outcomes are warranted.

Acetaminophen↗
PubMed1996

Randomized trials in single subjects: the N of 1 study.

Large-scale randomized trials are not available for all disorders, and conventional "trials of therapy" are susceptible to bias. Randomized controlled trials (RCTs) in individual patients (N of 1 RCTs) may provide a solution. In an N of 1 RCT, a patient receives treatments in pairs (one period of the experimental therapy and one period of either an alternative treatment or placebo, in random order), both patient and clinician are kept blind to allocation, and treatment targets are monitored. This type of RCT is useful in chronic, stable conditions in which the proposed treatment has a short half-life. Treatment targets usually include quantitative measurement of symptoms tracked through patient diaries. Pairs of treatment periods are continued until effectiveness is proved or refuted. The N of 1 RCT is potentially of great use in psychopharmacology and in drug development. The practical approach presented here will allow clinicians to conduct their own N of 1 RCTs.

Humans↗
PubMed1996

Systematic reviews, economic evaluations, and practice guidelines: can research synthesis help us care for the critically ill?

Blending the art and science of medicine in the ICU setting is a growing challenge, given modern technological advances, spiraling healthcare costs, and the need to carefully consider evidence from the biomedical literature in our practice. Rather than keeping up to date with all primary research relevant to critical care, intensivists are increasingly seeking synthetic research to help with their day-to-day decision-making. Synthetic research includes systematic reviews, practice guidelines, and economic evaluations. These publications can address questions of prevention, diagnosis, treatment, rehabilitation, and/or palliation, thereby helping intensivists to integrate the results of sound research at the bedside.

Cost-Benefit Analysis↗
PubMed1995

Importance of and satisfaction with work and professional interpersonal issues: a survey of physicians practicing general internal medicine in Ontario.

OBJECTIVES: To explore the importance of and satisfaction with clinical responsibilities, teaching, research and interpersonal issues among general internists; to understand the barriers to satisfaction in these domains and the usefulness of potential solutions to these problems. DESIGN: Cross-sectional survey conducted from November 1992 to June 1994. SETTING: Ontario. PARTICIPANTS: General internists who were fellows of the Royal College of Physicians and Surgeons of Canada and members of the Ontario Medical Association. Of 1192 physicians, 1007 (84.5%) returned a completed questionnaire; only the 199 who devoted at least 50% of their time to the practice of general internal medicine were included in this analysis. RESULTS: The respondents were satisfied with their primary role as clinicians dealing with complex, undifferentiated problems caring for the total patient and providing consultation. Guidelines for the referral of patients to general internists, computerization of test results, recruitment of general internal medicine fellows and more confidence in the future of general internal medicine were some of the solutions considered likely to increase professional satisfaction. The respondents involved in teaching suggested additional solutions, such as an opportunity to improve their teaching and evidence-based medicine skills and a greater recognition for their teaching efforts. Few of the general internists conducted research, barriers included lack of personal and project funding, and pressure to generate clinical earnings. In the domain of professional interpersonal issues, women were significantly more likely than men to rate having a mentor, peer support groups, ongoing career counselling, promotion and tenure guidelines for parental leave, availability of on-site day care, addressing gender discrimination and adoption of gender-neutral language as likely to improve the work environment. CONCLUSIONS: The primary role of general internists is that of patient-centred clinician. Our findings suggest that general internists want to take responsibility for revitalizing this discipline. The potential solutions generated in this survey may help to promote action that will improve professional satisfaction in the area of clinical responsibilities, teaching, research and interpersonal issues.

Adult↗
PubMed1995

Determinants in Canadian health care workers of the decision to withdraw life support from the critically ill. Canadian Critical Care Trials Group.

OBJECTIVE: To examine the attitudes of health care workers regarding the withdrawal of life support. DESIGN: Cross-sectional survey. PARTICIPANTS: Attending staff, house staff, and intensive care unit (ICU) nurses in 37 Canadian university-affiliated hospitals. MAIN OUTCOME MEASURES: Health care workers' ratings of the importance of 17 factors considered in the decision to withdraw life support, and their ratings of five levels of care ranging from comfort measures to intensive care in two of 12 different clinical scenarios. RESULTS: We surveyed 1361 respondents (149 of 167 potentially eligible ICU attending staff, 142 of 173 ICU house staff, and 1070 of 1455 ICU nurses, with response rates of 89%, 82% and 74%, respectively). The most important factors were likelihood of surviving the current episode, likelihood of long-term survival, premorbid cognitive function, and age of the patient. In choosing the level of care for the patient scenarios, the same option was chosen by more than 50% of respondents in only one of 12 scenarios; opposite extremes of care were chosen by more than 10% of the respondents in eight of 12 scenarios. Respondent characteristics affecting choices included the number of years since graduation, the city and province in which they worked, the number of beds in their ICU, and their assessment of the likelihood that they would withdraw life support in comparison with their colleagues (P < .001 for all comparisons). CONCLUSIONS: While ICU health care workers consistently identify a number of patient factors as important in decisions to withdraw care, there is extreme variability, which may be explained in part by the values of individual health care providers.

Adult↗
PubMed1995

Inadequacy of intravenous heparin therapy in the initial management of venous thromboembolism.

To determine the adequacy of initial anticoagulation by intravenous heparin for patients who have deep venous thrombosis (DVT), and the factors that influence delayed anticoagulation, independent, duplicate chart review of 63 consecutive patients who had venography-proven DVT was conducted. Adequate heparinization (AH) was defined as an activated partial thromboplastin time (PTT) of more than 1.5 times the normal laboratory control. The proportions of patients achieving AH within 24 hours and 48 hours of initial heparin bolus were 46% and 62%, respectively. Patients who weighed more were less likely to achieve AH (p < 0.05), while patients receiving care from the thromboembolism service were more likely to achieve AH (p < 0.05). Low initial infusion rate was strongly but not significantly predictive of inadequate anticoagulation (p = 0.06). The mean heparin bolus and initial infusion rates were significantly lower than those suggested in the literature (p < 0.01). The AH rates were comparable to historical controls but suboptimal compared with the rates of 66% at 24 hours and 81% at 48 hours reported in association with heparin nomogram use (p < 0.05). A heparin nomogram is likely to achieve consistently higher rates of adequate heparinization.

Aged↗