Biomedical subjects
Publications and source records attributed to Deborah J Cook.
Thrombocytopenia is common in critically ill patients who receive heparin. However, heparin-induced thrombocytopenia (HIT) is a relatively uncommon explanation for thrombocytopenia in this patient population. This article describes clinical features of HIT and interpretation of laboratory tests for HIT antibodies from the perspective of the intensive care unit.
PURPOSE: To describe perspectives of nurses (RNs) and respiratory therapists (RTs) related to end-of-life care for critically ill patients. METHODS: For patients who had life support withdrawn in 4 Canadian university-affiliated ICUs, RNs and RTs reported their comfort level with decision making and process for 14 aspects of end-of-life care. RESULTS: Ninety-eight patients had life support withdrawn. Responses were received from 96 (98.0%) bedside RNs and 73 (74.5%) RTs. Most RNs (85/94, 90.4%) and RTs (50/73, 68.5%) were very comfortable with decisions to withhold cardiopulmonary resuscitation or to withdraw life support (83/94, 88.3% of RNs and 56/73, 76.7% of RTs). Most RNs (range 71.3%-80.65%) and RTs (60.0%-70.8%) were very comfortable with ventilation/oxygen withdrawal and sedation. Among paired responses for 72 (73.5%) of 98 patients, RTs rated less favorably than RNs ( P < .05): the quality of the physician explanation of the life support withdrawal process, the availability of the physician, the peacefulness of the dying process, and the amount of privacy for families. Suggested improvements included earlier and more inclusive discussions, clearer plans, and better preparation of families and the ICU team for patients' deaths. CONCLUSIONS: Most RNs and RTs were comfortable with decision making and the process of life support withdrawal, but they suggested several ways to improve end-of-life care.
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OBJECTIVE: The purpose of this study is to describe the prevalence, to analyze the incidence and independent risk factors for thrombocytopenia, and to examine the impact of thrombocytopenia developing in the intensive care unit (ICU) on patient outcome in a well-defined cohort of critically ill patients in a medical-surgical ICU. MATERIALS AND METHODS: As part of a prospective cohort study examining the frequency and clinical importance of venous thromboembolism in the ICU, we enrolled consecutive patients older than 18 years expected to be in the ICU for more than 72 hours. Exclusion criteria were an admitting diagnosis of trauma, orthopedic surgery or cardiac surgery, pregnancy, and life support withdrawal. Patients had platelet counts performed as directed by clinical need. We defined thrombocytopenia as a platelet count of less than 150 x 10(9)/L and severe thrombocytopenia as a platelet count of less than 50 x 10(9)/L. Protocol-directed care included routine thromboprophylaxis and twice weekly screening ultrasonography of the legs. Patients were followed to hospital discharge. RESULTS: Of the 261 enrolled patients, 121 (46%, 95% confidence interval [CI], 40%-53%) had thrombocytopenia (62 on ICU admission and 59 acquired during their ICU stay). Patients who developed a platelet count less than 150 x 10(9)/L during their ICU stay had higher ICU and hospital mortality (P = .03 and .005, respectively), required longer mechanical ventilation (P = .05), and were more likely to receive platelets (P < .001), fresh frozen plasma (P = .005), and red blood cell transfusions (P = .004) than patients who did not develop thrombocytopenia. The only independent risk factors for thrombocytopenia developing during the ICU stay were administration of nonsteroidal anti-inflammatory drugs before ICU admission (hazard ratio, 2.8; 95% CI, 1.3-6.0) and dialysis during the ICU stay (hazard ratio, 3.1; 95% CI, 1.2-7.8). Of the 33 patients who underwent 36 tests for heparin-induced thrombocytopenia, none tested positive. CONCLUSIONS: We found that about 50% of the patients admitted to the ICU had at least one platelet count of less than 150 x 10(9)/L during their ICU stay. Patients who developed thrombocytopenia were more likely to die, required longer duration of mechanical ventilation, and were more likely to require blood product transfusion. Heparin-induced thrombocytopenia was frequently suspected but did not develop in these critically ill patients.
PURPOSE: Thromboprophylaxis with low-molecular-weight heparin (LMWH) may be more effective than unfractionated heparin but also more likely to bioaccumulate and potentially cause bleeding in patients with renal insufficiency. The objectives of this study were to assess, among medical-surgical patients in the intensive care unit receiving dalteparin 5,000 IU daily for thromboprophylaxis, (1) the relationship between renal dysfunction and LMWH bioaccumulation as measured by trough anti-Xa levels, (2) the relationship between renal dysfunction and risk of bleeding as measured by a surrogate marker (peak anti-Xa levels), and (3) the relationship between anti-Xa levels, bleeding events, and thrombotic events. MATERIALS AND METHODS: In this prospective single-center cohort study, we enrolled patients 18 years or older, expected to stay 72 hours or longer, and with a creatinine clearance 30 mL/min or higher at intensive care unit admission. We administered 5,000 IU dalteparin subcutaneously each day. The main phase 1 objective was to detect bioaccumulation of dalteparin by measuring trough anti-Xa levels (22-23 hours post dalteparin). The main phase 2 objective was to examine the relationship between renal dysfunction and peak anti-Xa levels (4 hours post dalteparin). We recorded creatinine clearance daily and bleeding and thrombotic events, blinded to anti-Xa levels. RESULTS: We enrolled 19 patients aged 62.7 (13.2) years with an APACHE II score of 23.5 (9.4). We measured trough anti-Xa levels on 185 occasions in 19 patients; we measured peak anti-Xa levels on 113 occasions in 11 patients. We identified no bioaccumulation of LMWH in this study, as detected by trough anti-Xa levels. Most peak anti-Xa levels were in the conventional prophylactic range. CONCLUSIONS: When administered in prophylactic doses to critically ill patients with a wide range of calculated creatinine clearances, we found no evidence of bioaccumulation of dalteparin. If dalteparin does not bioaccumulate, it may be an attractive alternative agent for thromboprophylaxis.
PURPOSE: There is no randomized trial comparing low-molecular weight heparin (LMWH) and unfractionated heparin (UFH) for thromboprophylaxis in medical-surgical ICU patients. The primary objective of this randomized pilot study on LMWH vs UFH was to assess the feasibility of conducting a large randomized trial with respect to timely enrollment and blinded study drug administration, practicality of twice-weekly lower limb ultrasounds to screen for deep venous thrombosis, LMWH bioaccumulation and dose adjustment in renal insufficiency, and recruitment rates for a future trial in medical-surgical intensive care unit (ICU) patients. Its additional goals were to evaluate the suitability of the exclusion criteria and to document the range of research activities that precede accrual of patients into a trial to plan multisite management. MATERIALS AND METHODS: By computerized telephone randomization, we allocated 129 medical-surgical ICU patients to treatment with dalteparin 5,000 IU QD SC or that with UFH 5,000 IU BID SC. Within each clinical center, only the study pharmacist was not blinded. We performed bilateral lower limb compression ultrasounds within 48 hours of ICU admission, twice weekly, on suspicion of deep venous thrombosis, and 7 days after ICU discharge. Research coordinators and investigators at 7 centers reported the time they engaged in all research activities before the first patient was randomized. RESULTS: Timely complete study drug administration occurred after enrollment. More than 99% of scheduled doses were administered in a blinded fashion. Scheduled ultrasounds were performed without exception. No bioaccumulation of dalteparin was observed when creatinine clearance decreased to lower than 30 mL/min. Average recruitment was 2 patients/center per month before the study exclusion criteria were modified. Study startup activities required, on average, 65.5 hours of combined investigator and research coordinator time at each center. Careful examination of the accrual in the pilot study led to a reexamination of the Prophylaxis of Thromboembolism in Critical Care Trial (PROTECT) study exclusion criteria. CONCLUSIONS: This pilot study suggests that a multicenter randomized clinical trial comparing LMWH with UFH in critically ill medical-surgical patients is feasible. Pilot studies can improve the design of larger trials and may enhance successful timely completion.
PURPOSE: The reliability of clinical signs and the physical examination in the evaluation of deep venous thrombosis (DVT) in the critically ill is unknown. The purpose of this study was to determine the diagnostic properties of clinical examination for signs of DVT in a cohort of medical-surgical intensive care unit (ICU) patients using screening compression ultrasonography as a reference standard. MATERIALS AND METHODS: We prospectively included patients older than 18 years with an expected length of ICU stay of more than 72 hours. Patients underwent bilateral lower limb screening compression ultrasound twice weekly and structured physical examination twice weekly by 2 independent trained research coordinators blinded to the ultrasonography results. We classified patients according to 2 methods: method 1, a DVT Risk Stratification System of 3 categories and method 2, a DVT Risk Score, both of which use the history and physical examination to stratify patients for their risk of DVT. RESULTS: We included 239 patients in our study, 32 of whom had DVT based on the results of their compression ultrasound. We excluded 7 patients with DVT on ICU admission and 2 who did not undergo any structured examinations. We matched controls with cases (9:1) based on duration of ICU stay. Cases and controls were then allocated to low, moderate, and high risk strata for DVT. Using method 1, the area under the receiver operating characteristic curve (AUC) was 0.57 (95% CI, 0.33-0.78, P = .01). Using method 2, the AUC was 0.59 (95% CI, 0.42-0.75, P = .02). An AUC of 1.0 indicates an ideal test, and AUC of 0.50 indicates a test with no diagnostic utility. CONCLUSIONS: The history and physical examination for DVT are not useful in detecting lower limb DVT in the ICU.
PURPOSE: The frequency of clinically diagnosed venous thromboembolism (VTE) including deep venous thrombosis (DVT) and pulmonary embolism (PE) in medical-surgical critically ill patients is unclear. The objectives of this study were to estimate the prevalence and incidence of radiologically confirmed DVT and PE in medical-surgical intensive care unit (ICU) patients and to determine the impact of prophylaxis on the frequency of these events. MATERIALS AND METHODS: In a retrospective observational cohort study in 12 adult ICUs, we identified prevalent cases (diagnosed in the 24 hours preceding ICU admission up to 48 hours post-ICU admission) and incident cases (diagnosed 48 hours or more after ICU admission and up to 8 weeks after ICU discharge) of upper or lower limb DVT or PE. Deep venous thrombosis was diagnosed by compression ultrasound or venogram. Each DVT was classified as clinically suspected or not clinically suspected in that the latter was diagnosed by scheduled screening ultrasonography. Pulmonary embolism was diagnosed by ventilation-perfusion lung scan, computed tomography pulmonary angiography, echocardiography, electrocardiography, or autopsy. RESULTS: Among 12,338 patients, 252 (2.0%) patients had radiologically confirmed DVT or PE and another 47 (0.4%) had possible DVT or PE. Prevalent DVTs were diagnosed in 0.4% (95% confidence interval [CI], 0.3%-0.5%) of patients and prevalent PEs were diagnosed in 0.4% (95% CI, 0.3%-0.6%). Incident DVTs were diagnosed in 1.0% (95% CI, 0.8%-1.2%) of patients, and incident PEs were diagnosed in 0.5% (95% CI, 0.4%-0.6%). Of patients with incident VTE, 65.8% of cases occurred despite receipt of thromboprophylaxis for at least 80% of their days in ICU. The median (interquartile range) ICU length of stay was similar for patients with DVT (7 [3-17]) and PE (5 [2-8]). For all patients with VTE, ICU mortality was 16.7% (95% CI, 12.0%-21.3%) and hospital mortality was 28.5% (95% CI, 22.8%-34.1%). CONCLUSIONS: Venous thromboembolism appears to be an apparently infrequent, but likely underdiagnosed problem, occurring among patients receiving prophylaxis. Findings suggest the need for increased suspicion among clinicians, renewed efforts at thromboprophylaxis, and evaluation of superior prevention strategies.
OBJECTIVE: To determine physicians' stated practices regarding the use of bilevel noninvasive ventilation (NIV) for acute respiratory failure and the predictors of practice variation. DESIGN: Cross-sectional postal survey. SETTING: Province of Ontario, Canada. PARTICIPANTS: Attending physicians and residents in four specialties at 15 teaching hospitals. INTERVENTIONS: We used literature searches and focus groups to design questions related to NIV utilization with respect to frequency, location of and indications for use, awareness of supporting literature, and perceived efficacy. We assessed the survey's clinical sensibility and reliability. We used regression analyses to evaluate practice variation among hospitals and specialties and to determine predictors of more frequent NIV use, initiation of and continued use in nonmonitored settings, and use for specific indications. MEASUREMENTS AND MAIN RESULTS: Three hundred eighty-five (48%) of 808 physicians responded; 242 used NIV. The two most common indications for NIV use were chronic obstructive pulmonary disease and congestive heart failure. NIV guidelines, protocols, or policies were available in 12 of 15 hospitals. We found variation in NIV utilization among specialties but not hospitals. Specialty (critical care and respirology versus internal and emergency medicine), fewer years of postgraduate experience, and a greater number of noninvasive ventilators were predictors of more frequent NIV use (all p < or = .001). Only 6% of respondents reported initiation of use and continued use most frequently in nonmonitored settings, which increased with the number of noninvasive ventilators (p = .02). Physician characteristics such as awareness of the literature were predictive of NIV use for exacerbations of chronic obstructive pulmonary disease, whereas perceived NIV efficacy was predictive of use for many indications, including congestive heart failure. CONCLUSIONS: Self-reported practice variation for bilevel NIV exists among specialties but not hospitals and differs with respect to frequency, location of use, and use for specific indications. Some factors associated with variation in NIV use may be suitable targets for utilization improvement interventions.
OBJECTIVES: To evaluate the quality of reporting among abstracts of randomized controlled trials (RCTs) in acute lung injury and to highlight important trial information for abstract inclusion. DESIGN: Audit of published RCT abstracts. SAMPLE: A total of 56 RCTs, identified in MEDLINE, EMBASE, HEALTHSTAR, CINAHL, and the Cochrane Central Register of Controlled Trials. MEASUREMENTS AND MAIN RESULTS: We used a research focus group and published literature on suggested content for abstracts of original articles to generate a list of 32 recommended items. The focus group reduced this list to a 20-item long form list of highly relevant criteria and a 12-item short form list of essential criteria for inclusion in abstracts of RCTs in acute lung injury. After pilot testing the abstract appraisal form, we evaluated abstracts independently and in duplicate. We scored the quality of reporting of each abstract by dividing the number of criteria fulfilled by the number applicable. Although abstracts described the study objectives and interventions well and the participants, outcomes, and conclusions to an intermediate extent, key deficiencies were noted in reporting the study methods, setting, and results. Mean quality of reporting scores were significantly higher for structured compared with unstructured abstracts using the 32-item, 20-item, and 12-item lists (p = .008, .014, and <.0001, respectively), especially for abstracts published after 1990 (p = .004, .017, and .001, respectively). The 20-item and 12-item lists correlated well with the 32-item list (r = .89 and .62, respectively) and with one another (r = .73). CONCLUSIONS: Key design features and results are frequently under-reported in RCT abstracts, particularly among unstructured abstracts. Checklists may aid authors and editors in prioritizing important criteria for inclusion in RCT abstracts.
OBJECTIVE: To assess the methodologic quality of meta-analyses of general surgery topics published in peer-reviewed journals. SUMMARY BACKGROUND DATA: Systematic reviews and meta-analysis are used to seek, summarize, and interpret primary studies on a given topic. Accordingly, systematic reviews and meta-analyses of high-quality primary studies may be the highest level of evidence for issues of prevention and treatment in evidence-based medicine. However, not all published meta-analyses are rigorously performed. METHODS: We searched MEDLINE (from January 1, 1997, to September 1, 2002) and reference lists and solicited general surgery specialists to identify relevant meta-analyses. Inclusion criteria were use of meta-analytic methods to pool the results of primary studies in general surgery on issues of diagnosis, causation, prognosis, or treatment. Our search strategies identified 487 potentially relevant articles. After excluding articles based on a priori criteria, 51 meta-analyses fulfilled eligibility criteria. In duplicate and independently, 2 reviewers assessed the quality of these meta-analyses using a 10-item index called the Overview Quality Assessment Questionnaire. RESULTS: Overall concordance between 2 independent reviewers was good (interobserver agreement 81%, and a kappa of 0.62 (95% CI 0.55-0.69). Of 51 relevant articles, 38 were published in surgical journals. Most studies had major methodologic flaws (median score of 3.3, scale of 1-7). Factors associated with low overall scientific quality included the absence of any prior meta-analyses publications by authors and meta-analyses produced by surgical department members without external collaboration. CONCLUSIONS: This critical appraisal of meta-analyses published in the general surgery literature demonstrates frequent methodologic flaws. The quality of these reports limits the validity of the findings and the inferences that can be made about the primary studies reviewed. To improve the quality of future meta-analyses, we recommend following guidelines for the optimal conduct and reporting of meta-analyses in general surgery.
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A novel assay for endotoxin, based on the ability of antigen-antibody complexes to prime neutrophils for an augmented respiratory burst response, was studied in a cohort study of 857 patients admitted to an intensive-care unit (ICU). On the day of ICU admission, 57.2% of patients had either intermediate (>or=0.40 endotoxin activity [EA] units) or high (>or=0.60 units) EA levels. Gram-negative infection was present in 1.4% of patients with low EA levels, 4.9% with intermediate levels, and 6.9% with high levels; EA had a sensitivity of 85.3% and a specificity of 44.0% for the diagnosis of gram-negative infection. Rates of severe sepsis were 4.9%, 9.2%, and 13.2%, and ICU mortality was 10.9%, 13.2%, and 16.8% for patients with low, intermediate, and high EA levels, respectively. Stepwise logistic regression analysis showed that elevated Acute Physiology and Chronic Health Evaluation II score, gram-negative infection, and emergency admission status were independent predictors of EA.
BACKGROUND: It has been shown that patients cared for at private for-profit hospitals have higher risk-adjusted mortality rates than those cared for at private not-for-profit hospitals. Uncertainty remains, however, about the economic implications of these forms of health care delivery. Since some policy-makers might still consider for-profit health care if expenditure savings were sufficiently large, we undertook a systematic review and meta-analysis to compare payments for care at private for-profit and private not-for-profit hospitals. METHODS: We used 6 search strategies to identify published and unpublished observational studies that directly compared the payments for care at private for-profit and private not-for-profit hospitals. We masked the study results before teams of 2 reviewers independently evaluated the eligibility of all studies. We confirmed data or obtained additional data from all but 1 author. For each study, we calculated the payments for care at private for-profit hospitals relative to private not-for-profit hospitals and pooled the results using a random effects model. RESULTS: Eight observational studies, involving more than 350 000 patients altogether and a median of 324 hospitals each, fulfilled our eligibility criteria. In 5 of 6 studies showing higher payments for care at private for-profit hospitals, the difference was statistically significant; in 1 of 2 studies showing higher payments for care at private not-for-profit hospitals, the difference was statistically significant. The pooled estimate demonstrated that private for-profit hospitals were associated with higher payments for care (relative payments for care 1.19, 95% confidence interval 1.07-1.33, p = 0.001). INTERPRETATION: Private for-profit hospitals result in higher payments for care than private not-for-profit hospitals. Evidence strongly supports a policy of not-for-profit health care delivery at the hospital level.
PURPOSE: Setting treatment goals in the intensive care unit (ICU) often involves resuscitation decisions. Our objective was to study the rate of establishing do-not-resuscitate (DNR) directives, determinants, and outcomes of those directives for mechanically ventilated patients. METHODS: In a multicentre observational study, we included consecutive adults with no DNR directives within 24 hr of ICU admission who were mechanically ventilated for at least 48 hr. We identified the rate with which DNR directives were established, and factors associated with these directives. RESULTS: Among 765 patients, DNR directives were established for 231 (30.2%) patients; 143 (62.1%) of these were established within the first week. Factors independently associated with a DNR directive were: patient age [> or = 75 yr (hazard ratio [HR] 2.3, 95% confidence interval 1.5-3.4], 65 to 74 yr (HR 1.8, 1.2-2.7), 50 to 64 yr (HR 1.4, 1.0-2.2) relative to < 50 yr); medical rather than surgical diagnosis (HR 1.8, 1.3-2.5); multiple organ dysfunction score (HR 1.7 for each five-point increment, 1.4-2.0); physician prediction of ICU survival [< 10% (HR 15.0, 6.7-33.6)], 10 to 40% [(HR 5.0, 2.3-11.2), 41 to 60% (HR 4.0, 1.8-9.0) relative to > 90%]; and physician perception of patient preference to limit life support (no advanced life support [(HR 5.8, 3.6-9.4) or partial advanced life support (HR 3.2, 2.2-4.6) compared to full measures]. CONCLUSION: One third of mechanically ventilated patients had DNR directives established early during their ICU stay after the first 24 hr of admission. The strongest predictors of DNR directives were physician prediction of low probability of survival, physician perception of patient preference to limit life support, organ dysfunction, medical diagnosis and age.
PURPOSE: To conduct a systematic review of educational advance care planning interventions directed at patients without terminal illness to determine their influence on the completion rate of advance directives (AD). MATERIALS AND METHODS: We searched MEDLINE; Cochrane Library, and reference lists of all pertinent retrieved articles for randomized trials (RCTs), restricted to English language and adults > or =18 years. Two investigators independently and in duplicate determined trial eligibility. We included published RCTs evaluating an educational intervention comprised of at least one of; written, audio, or video materials, or direct counseling, and if an outcome included AD completion rate. RESULTS: Nine RCTs (N=3,206) were included. Overall, methodologic quality and reporting transparency were poor. The median composite quality score was 5 (range, 0-10). The odds ratios for AD completion rates ranged from 0.41 to 106.0 across the trials (test of heterogeneity P <.001). The summary odds ratio for these educational interventions was 3.71 (95% C.I. 1.46, 9.40). Trials with greater methodologic rigor and reporting transparency produced a more conservative estimate of effect, 2.42 [0.96, 6.10] versus 28.69 [5.08, 162.06] for less rigorous and poorly reported trials (P =.013). CONCLUSIONS: Advance directive completion rates documenting patient preferences for end-of-life care may be increased by simple patient-directed educational interventions.