Showing papers by "Deborah J. Cook published in 1999"

The Attributable Morbidity and Mortality of Ventilator-Associated Pneumonia in the Critically Ill Patient

Abstract: To evaluate the attributable morbidity and mortality of ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients, we conducted a prospective, matched cohort study. Patients expected to be ventilated for > 48 h were prospectively followed for the development of VAP. To determine the excess ICU stay and mortality attributable to VAP, we matched patients with VAP to patients who did not develop clinically suspected pneumonia. We also conducted sensitivity analyses to examine the effect of different populations, onset of pneumonia, diagnostic criteria, causative organisms, and adequacy of empiric treatment on the outcome of VAP. One hundred and seventy-seven patients developed VAP. As compared with matched patients who did not develop VAP, patients with VAP stayed in the ICU for 4.3 d (95% confidence interval [CI]: 1.5 to 7.0 d) longer and had a trend toward an increase in risk of death (absolute risk increase: 5.8%; 95% CI: − 2.4 to 14.0 d; relative risk (RR) increase: 32.3%; 95% CI: − 20....

Crystalloids vs. colloids in fluid resuscitation: a systematic review.

Abstract: ObjectiveTo systematically review the effects of isotonic crystalloids compared with colloids in fluid resuscitation.Data SourcesComputerized bibliographic search of published research and citation review of relevant articles.Study SelectionAll randomized clinical trials of adult patients requiring

Isoniazid for preventing tuberculosis in non-HIV infected persons.

Abstract: Background Although isoniazid (INH) is commonly used for treating tuberculosis (TB), it is also effective as preventive therapy. Objectives The objective of this review was to estimate the effect of six and 12 month courses of INH for preventing TB in HIV-negative people at increased risk of developing active TB. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register (May 2003), CENTRAL (The Cochrane Library 2003, Issue 2), Science Citation Index (1955 to 1993), Cumulated Index Medicus (1960 to 1970), MEDLINE (1966 to May 2003), EMBASE (1974 to May 2003), and reference lists of articles. Selection criteria Randomized controlled trials of INH preventive therapy for six months or more compared with placebo. Follow up for a minimum of two years. Trials enrolling patients with current or previously treated active TB or with known HIV infection were excluded. Criteria were applied by two reviewers independently. Data collection and analysis Trial quality was assessed by two reviewers independently, and data extracted by one reviewer using a standardized extraction form. Main results Eleven trials involving 73,375 patients were included. Trials were generally of high quality. Treatment with INH resulted in a risk ratio (RR) of developing active TB of 0.40, (95% confidence interval (CI) 0.31 to 0.52), over two years or longer. There was no significant difference between six and 12 month courses (RR 0.44, 95% CI 0.27 to 0.73 for six months, and 0.38, 95% CI 0.28 to 0.50 for 12 months). Preventive therapy reduced deaths from TB, but this effect was not seen for all-cause mortality. INH was associated with hepatotoxicity in 0.36% of people on six months of treatment and in 0.52% of people treated for 12 months. Authors' conclusions Isoniazid prevents active TB in diverse at-risk patients, and six- and 12-month regimens have a similar effect. The most recent trial included in the review was published in 1994, and we have not identified any relevant trials up to 2003. We therefore do not plan to update this review.

Assessing the quality of reports of randomised trials: implications for the conduct of meta-analyses.

Abstract: 1 Thomas C Chalmers Centre for Systematic Reviews, Children’s Hospital of Eastern Ontario Research Institute, Canada 2 Department of Pediatrics, University of Ottawa, Canada 3 Department of Clinical Epidemiology and Biostatistics, McMaster University, Canada 4 Health Information Research Unit, Department of Clinical Epidemiology and Biostatistics, McMaster University, Canada 5 Department of Medicine, University of Ottawa, Canada 6 Division of Public Health and Primary Health Care, Institute of Health Sciences, University of Oxford, UK

Risk factors for clinically important upper gastrointestinal bleeding in patients requiring mechanical ventilation. Canadian Critical Care Trials Group.

Abstract: Objective:To evaluate the incidence and risk factors for clinically important upper gastrointestinal bleeding in critically ill patients requiring mechanical ventilation.Design:In duplicate, blinded adjudicators determined the presence of clinically important gastrointestinal bleeding using a priori

Does this adult patient have acute meningitis

Abstract: Context Early clinical recognition of meningitis is imperative to allow clinicians to efficiently complete further tests and initiate appropriate therapy. Objective To review the accuracy and precision of the clinical examination in the diagnosis of adult meningitis. Data Sources A comprehensive review of English- and French-language literature was conducted by searching MEDLINE for 1966 to July 1997, using a structured search strategy. Additional references were identified by reviewing reference lists of pertinent articles. Study Selection The search yielded 139 potentially relevant studies, which were reviewed by the first author. Studies were included if they described the clinical examination in the diagnosis of objectively confirmed bacterial or viral meningitis. Studies were excluded if they enrolled predominantly children or immunocompromised adults or focused only on metastatic meningitis or meningitis of a single microbial origin. A total of 10 studies met the criteria and were included in the analysis. Data Extraction Validity of the studies was assessed by a critical appraisal of several components of the study design. These components included an assessment of the reference standard used to diagnose meningitis (lumbar puncture or autopsy), the completeness of patient ascertainment, and whether the clinical examination was described in sufficient detail to be reproducible. Data Synthesis Individual items of the clinical history have low accuracy for the diagnosis of meningitis in adults (pooled sensitivity for headache, 50% [95% confidence interval {CI}, 32%-68%]; for nausea/vomiting, 30% [95% CI, 22%-38%]). On physical examination, the absence of fever, neck stiffness, and altered mental status effectively eliminates meningitis (sensitivity, 99%-100% for the presence of 1 of these findings). Of the classic signs of meningeal irritation, only 1 study has assessed Kernig sign; no studies subsequent to the original report have evaluated Brudzinski sign. Among patients with fever and headache, jolt accentuation of headache is a useful adjunctive maneuver, with a sensitivity of 100%, specificity of 54%, positive likelihood ratio of 2.2, and negative likelihood ratio of 0 for the diagnosis of meningitis. Conclusions Among adults with a clinical presentation that is low risk for meningitis, the clinical examination aids in excluding the diagnosis. However, given the seriousness of this infection, clinicians frequently need to proceed directly to lumbar puncture in high-risk patients. Many of the signs and symptoms of meningitis have been inadequately studied, and further prospective research is needed.

Users' guides to the medical literature XVI. How to use a treatment recommendation

Abstract: Clinicians can often find treatment recommendations in traditional narrative reviews and the discussion sections of original articles and metaanalyses. Making a treatment recommendation involves framing a question, identifying management options and outcomes, collecting and summarizing evidence, and applying value judgments or preferences to arrive at an optimal course of action. Each step in this process can be conducted systematically (thus protecting against bias) or unsystematically (leaving the process open to bias). Clinicians faced with a plethora of recommendations may wish to attend to those that are less likely to be biased. Therefore, we propose a hierarchy of rigor of recommendations to guide clinicians when judging the usefulness of particular recommendations. Recommendations with the highest rigor consider all relevant options and outcomes, include a comprehensive collection of the methodologically highest quality data with an explicit strategy for summarizing the data (that is, a systematic review), and make an explicit statement of the values or preferences involved in moving from evidence to action. High rigor recommendations come from systematically developed, evidence-based practice guidelines or rigorously conducted decision analyses. Systematic reviews, which typically do not consider all relevant options and outcomes or make the preferences underlying recommendations explicit, offer intermediate rigor recommendations. Traditional approaches in which the collection and assessment of evidence remains unsystematic, all relevant options and outcomes may not be considered, and values remain implicit, provide recommendations of weak rigor. In an era in which clinicians are barraged by recommendations as to how to manage their patients, this hierarchy provides a potentially useful set of guides.

Users' Guides to the Medical Literature: XV. How to Use an Article About Disease Probability for Differential Diagnosis

Abstract: CLINICAL SCENARIO You are an experienced clinician working at a hospital emergency department. One morning, a 33-year-old man presents with palpitations. He describes the new onset of episodes of fast, regular chest pounding, which come on gradually, last 1 to 2 minutes, and occur several times a day. He reports no relation of symptoms to activities and no change in exercise tolerance. He is very anxious and tells you he fears heart disease. He has no other symptoms, no personal or family history of heart disease, and takes no medications. His heart rate is 90 bpm and regular, and physical examination of his eyes, thyroid gland, lungs, and heart is normal. His 12-lead electrocardiogram is normal, without arrhythmia or signs of pre-excitation. You suspect his anxiety explains his palpitations, that they are mediated by hyperventilation, and are possibly part of a panic attack. While he has no findings of cardiac arrhythmia or hyperthyroidism, you wonder if these disorders are common enough in the emergency department setting to consider seriously. You reject pheochromocytoma as too unlikely. Thus, you can list causes of palpitations, but want more information about the frequency of these causes to choose a diagnostic work-up. You ask the question: “In patients presenting with palpitations, what is the frequency of underlying disorders?”

Transthoracic needle aspiration biopsy for the diagnosis of localised pulmonary lesions: a meta-analysis.

Abstract: BACKGROUND Persisting controversy surrounds the use of transthoracic needle aspiration biopsy (TNAB) stemming from its uncertain diagnostic accuracy. A systematic review and meta-analysis was therefore conducted to evaluate the accuracy of TNAB for the diagnosis of solitary or multiple localised pulmonary lesions. METHODS Searches for English literature papers in Index Medicus (1963–1965) and Medline (1966–1996) were performed and the bibliographies of the retrieved articles were systematically reviewed. Articles evaluating the accuracy of TNAB in series of consecutive patients presenting with solitary or multiple pulmonary lesions were considered. Only papers in which ⩾90% of patients were given a final diagnosis according to an appropriate reference standard were included in the meta-analysis. RESULTS A total of 48 studies were included and five meta-analyses were conducted according to four diagnostic thresholds. From the pooled sensitivity and specificity corresponding to each diagnostic threshold, associated likelihood ratios (LRs) were derived for malignant disease as follows: (1) malignant versus all other categories, LR = 72; (2) malignant or suspicious versus all others, LR = 49; (3) suspicious versus all categories but malignant, LR = 15; (4) benign versus all others, LR = 0.07; and (5) specific benign diagnosis versus all others, LR = 0.005. Differences in methodological quality of the studies, needle types, or whether a cytopathologist participated in the procedure failed to explain the heterogeneity of the results found in almost every meta-analysis. Given a 50% probability of malignancy prior to the TNAB, post-test probabilities of malignancy upon receiving the results would be malignant, 99%; suspicious, 94%; non-specific benign, 7%; and benign with a specific diagnosis, 0.6%. CONCLUSIONS Given the intermediate pre-test probabilities that would probably lead to performing TNAB, findings of “malignant” or of a specific diagnosis of a benign condition provide definitive results. Findings of “suspicious” markedly increase the probability of malignancy, and “benign” markedly decreases it but may not be considered definitive.

The effect of acidified enteral feeds on gastric colonization in critically ill patients: results of a multicenter randomized trial

Abstract: Objective: To evaluate the effect of acidified enteral feeds on gastric colonization in critically III patients compared with a standard feeding formula. Design: Randomized, double-blind, multicenter trial. Setting: Eight mixed intensive care units at tertiary care hospitals Patients: We recruited mechanically ventilated critically ill patients expected to remain ventilated for >48 hrs. We excluded patients with gastrointestinal bleeding, acidemia, and renal failure requiring dialysis. We enrolled 120 patients; 38% were female, age (mean ± SD) was 57.6 ± 19.3 yrs, and Acute Physiology and Chronic Health Evaluation II score (mean ± SD) was 21.6 ± 7.6. Interventions: Vital High Nitrogen (Abbott Laboratories, Ross Products Division, Columbus, OH) was used as the standard feeding formula for the control group (pH = 6.5). Hydrochloric acld was added to Vital High Nitrogen to achieve a pH of 3.5 in the experimental group. Measurements and Main Results: The main outcome measure was gastric colonization. Secondary outcomes included gastric pH, pneumonia, and mortality. The mean gastric pH in patients receiving acid feeds was lower (pH = 3.3) compared with controls (pH = 4.6; p <.05). One patient (2%) on acid feeds was colonized in the stomach with pathogenic bacteria, compared with 20 patients (43%) in the control group (p <.001). There was no difference in the incidence of pneumonia (6.1% in the acid feeds group vs. 15% in the control group; p =.19). Overall, there were 15 deaths in the acid feeds group and seven in the control group (p =.10); four patients in the acid feeds group and three in the control group died during the study period (p not significant). Conclusions: Acidified enteral feeds preserve gastric acidity and substantially reduce gastric colonization in critically ill patients. Larger studies are needed to examine its effect on ventilator-associated pneumonia and mortality.

Life support in the intensive care unit: a qualitative investigation of technological purposes

Abstract: BACKGROUND: The ability of many intensive care unit (ICU) technologies to prolong life has led to an outcomes-oriented approach to technology assessment, focusing on morbidity and mortality as clinically important end points. With advanced life support, however, the therapeutic goals sometimes shift from extending life to allowing life to end. The objective of this study was to understand the purposes for which advanced life support is withheld, provided, continued or withdrawn in the ICU. METHODS: In a 15-bed ICU in a university-affiliated hospital, the authors observed 25 rounds and 11 family meetings in which withdrawal or withholding of advanced life support was addressed. Semi-structured interviews were conducted with 7 intensivists, 5 consultants, 9 ICU nurses, the ICU nutritionist, the hospital ethicist and 3 pastoral services representatives, to discuss patients about whom life support decisions were made and to discuss life-support practices in general. Interview transcripts and field notes were analysed inductively to identify and corroborate emerging themes; data were coded following modified grounded theory techniques. Triangulation methods included corroboration among multiple sources of data, multidisciplinary team consensus, sharing of results with participants and theory triangulation. RESULTS: Although life-support technologies are traditionally deployed to treat morbidity and delay mortality in ICU patients, they are also used to orchestrate dying. Advanced life support can be withheld or withdrawn to help determine prognosis. The tempo of withdrawal influences the method and timing of death. Decisions to withhold, provide, continue or withdraw life support are socially negotiated to synchronize understanding and expectations among family members and clinicians. In discussions, one discrete life support technology is sometimes used as an archetype for the more general concept of technology. At other times, life-support technologies are discussed collectively to clarify the pursuit of appropriate goals of care. CONCLUSIONS: The orchestration of death involves process-oriented as well as outcome-oriented uses of technology. These uses should be considered in the assessment of life-support technologies and directives for their appropriate use in the ICU.

Development and validation of the mini-osteoporosis quality of life questionnaire (OQLQ) in osteoporotic women with back pain due to vertebral fractures. Osteoporosis Quality of Life Study Group.

Abstract: The objective of the study was to evaluate a shortened osteoporosis quality of life questionnaire (OQLQ) in osteoporotic women with back pain due to vertebral fractures. From the longer 30-item OQLQ (four to nine items per domain) we created the mini-OQLQ by choosing the two items with the highest impact in each of five domains (symptoms, physical function, activities of daily living, emotional function, leisure). We administered the OQLQ, the Sickness Impact Profile, the SF-36 and the Brief Pain Index to patients at baseline, after 2 weeks and after 6 months. The intraclass correlations between baseline and the 2-week follow-up for the five mini-OQLQ domains ranged from 0.72 to 0.86. Cross-sectional correlations between the domains of the mini-OQLQ and other health instruments were moderate to large (0.35-0.80) and greater than predicted. The mini-OQLQ items showed moderate to large correlations with items omitted from the shortened questionnaire (0. 44-0.88). Correlations between the OQLQ domains and the other three instruments were greater than those of the mini-OQLQ, and partial correlations between OQLQ items omitted from the mini-OQLQ and the other three instruments after considering mini-OQLQ items were substantial (0.19-0.71) and statistically significant. Sample sizes of less than 200 per group should be required to detect minimally important differences in parallel-group clinical trials. Longitudinal correlations between the mini-OQLQ and the other measures were often significant but generally lower than predicted (0.10-0.49). The partial correlations revealed that the omitted items explained a significant portion of the longitudinal variance in each domain. We conclude that in a selected group of patients with back pain caused by vertebral fractures, the mini-OQLQ demonstrated good discriminative and adequate evaluative properties. The mini-questionnaire should be useful in clinical settings.

The clinical utility of invasive diagnostic techniques in the setting of ventilator-associated pneumonia

Abstract: Objective To evaluate the clinical utility of bronchoscopy with protected brush catheter (PBC) and BAL for patients with ventilator-associated pneumonia (VAP). Design Prospective cohort study. Setting Ten tertiary care ICUs in Canada. Patients Ninety-two mechanically ventilated patients with a clinical suspicion of VAP who underwent bronchoscopy were compared with 49 patients with a clinical suspicion of pneumonia who did not. Interventions None. Measurements and results We compared antibiotic use, duration of mechanical ventilation, ICU stay, and mortality. In addition, for patients who received bronchoscopy, we administered a questionnaire (before and after bronchoscopy) to evaluate the effect of PBC or BAL on (1) physician perception of the probability of VAP, (2) physician confidence in the diagnosis of VAP, and (3) changes to antibiotic management. After bronchoscopy results became available, from the physician's perspective, the diagnosis of VAP was deemed much less likely (p Conclusions Invasive diagnostic testing may increase physician confidence in the diagnosis and management of VAP and allows for greater ability to limit or discontinue antibiotic treatment. Whether performing PBC or BAL affects clinically important outcomes requires further study.

Attitudes of Swedish physicians and nurses towards the use of life-sustaining treatment.

Abstract: Background: Withdrawal or withholding of life-sustaining treatment have become accepted clinical practice within the intensive care unit (ICU). One important factor influencing these decisions is the attitudes of physicians and nurses. Method: Questionnaire survey of physicians and nurses in ICUs in 12 Swedish university-affiliated and/or tertiary referral hospitals. Results: The response rate was 850 of 1081 (79%) potentially eligible health care workers. Respondents first rated the importance of 16 factors considered in the decision to withdraw life support. The most important factors were the patient’s likelihood of surviving the current episode, patient advance directives, patient age and likelihood of long-time survival. Respondents also chose between five levels of care, ranging from comfort measures to full intensive care, in two of 12 different scenarios. Respondent characteristics affecting the level of care chosen were the number of years of ICU experience and the particular ICU in which the respondent worked. Conclusion: Advance directives are believed by Swedish intensive care personnel to be very important in the decision to withdraw life support, contrary to several descriptive studies suggesting modest patient and family influence on these decisions. Attitudes towards the intensity of care vary between different centers, raising the possibility that levels of care for similar patients may differ across the country.

The sound of silence: rationing resources for critically ill patients

Abstract: Thirty years ago, the rationing of healthcare was invisible and silent. Recently, however, healthcare expenditures have become a major focus of public policy. As we look for ways to control spending, we become more aware of the economic trade-offs involved in every healthcare decision. Allocating resources to one service means less left for other services; allocating resources to one patient means less resources available for others. Rationing is becoming more publicly visible and explicit at every level of the healthcare system. However, in many intensive care units (ICUs) rationing still remains silent — implicitly conducted and inadequately discussed. If we agree that healthcare resources are fixed and the needs and demands for health resources are not [1], then all resource allocation decisions are rationing decisions. Rationing implies that, because of cost constraints, not everyone will get every service they need, want, or even deserve. Encouraging clinicians to become aware of rationing in their own practice [2], Ubel and Goold suggested that three conditions must be met to label an activity as bedside rationing: (1) physicians have control over the use of a beneficial service; (2) they withhold, withdraw or fail to offer a service that is in the patient's best medical interest; and (3) they act primarily to promote the interests of someone other than the patient (this could be either the physician, an organization, or society in general — by reserving healthcare resources for other patients). This editorial is for intensivists interested in reflecting on the rationing of critical care services. Here we focus on (1) how ICU resources are currently rationed; (2) basic principles at stake in our rationing decisions; and (3) our multiple roles in the rationing process.

How to use articles about diagnostic technology: gastric tonometry.

Abstract: Purpose Periodic diagnostic tests and continuous and intermittent monitoring are integral to critical care medicine. The focus of this article is understanding the impact of existing diagnostic technology, as well as that of new diagnostic technology. Data synthesis We use literature about gastric tonometry to illustrate eight steps for assessing the value of diagnostic technology. Methods These steps focus on how the technology works in the laboratory, its range of uses and diagnostic accuracy, its impact on healthcare workers, the decision making process, and patient outcomes, as well as issues of access, cost, and application in your own setting. Conclusions Awareness of the scope and quality of research evaluating new and existing diagnostic technology is central to modern critical care practice.

The promise and the paradox of technology in the intensive care unit.

Abstract: Although health-related technology encompasses the drugs, devices, procedures and organizations used in health care delivery,[1][1] in this article we focus on the devices used to care for critically ill patients. There are few settings as evocative of health technology as the intensive care unit (

Interpreting, integrating, and individualizing evidence about the prevention of diabetic nephropathy.

Abstract: Golan and colleagues' decision analysis in this issue focuses on the prevention of diabetic neuropathy under three scenarios. This study highlights the reality that clinicians and patients with dif...