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Biomedical subjects

G Doig

Publications and source records attributed to G Doig.

15 recordsLinked to original sources
PubMed2006

Pulmonary artery catheters for adult patients in intensive care.

BACKGROUND: Pulmonary artery catheterization was adopted about 30 years ago and widely disseminated without rigorous evaluation as to whether it benefited critically ill patients. The technique is used to measure cardiac output and pressures in the pulmonary circulation to guide diagnosis and treatment. Clinicians believe these data can improve patients' outcomes, even in the absence of consensus about the specific interpretation of the data. OBJECTIVES: To assess the effect of pulmonary artery catheterization on mortality and cost of care in adult intensive care patients. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2006); MEDLINE (all records to April 2006); EMBASE (all records to April 2006); CINAHL (all records to April 2006) and reference lists of articles. We contacted manufacturers and researchers in the field. SELECTION CRITERIA: We included all randomized controlled trials in adults, comparing management with and without a pulmonary artery catheter (PAC). DATA COLLECTION AND ANALYSIS: We screened the titles and abstracts of the electronic search results and obtained the full text of studies of possible relevance for independent review. We determined the final results of the literature search by consensus between the authors. We did not contact study authors for additional information. MAIN RESULTS: We identified 12 studies. Mortality was reported as hospital, 28-day, 30-day, or intensive care unit. We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (four studies) separately for the meta-analysis. The pooled odds ratio for the studies of general intensive care patients was 1.05 (95% confidence interval (CI) 0.87 to 1.26) and for the studies of high-risk surgery patients 0.99 (95% CI 0.73 to 1.24). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. Pulmonary artery catheterization did not affect intensive care unit (reported by 10 studies) or hospital (reported by nine studies) length of stay. Four studies, conducted in the United States, measured costs based on hospital charges billed to patients, which on average were higher in the PAC groups. AUTHORS' CONCLUSIONS: To date, there have been two multi-centre trials of the effectiveness of PACs for managing critically ill patients admitted to intensive care, although only one was adequately powered. Efficacy studies are needed to determine optimal management protocols and patient groups who could benefit from management with a PAC.

Adult↗
PubMed2001

The Southwestern Ontario Joint Replacement Pilot Project: electronic point-of-care data collection. Southwestern Ontario Study Group.

OBJECTIVE: To pilot a provincial joint replacement registry using electronic point-of-care data collection. DESIGN: Data collection study. SETTING: Southwestern Ontario, which has a population base of 3.5 million people. PARTICIPANTS: Eighteen orthopedic surgeons. METHOD: Information on total hip and knee replacements was obtained by the orthopedic surgeons over a 6-month period. Information was obtained in paper form and electronically on hand-held computers. MAIN OUTCOME MEASURES: Patient demographics, waiting times from referral to operation, patient satisfaction and relevance and value of electronic records compared with paper records. MAIN RESULTS: Data were collected on 815 total hip and knee arthroplasties. A slightly greater number of hips required revision than knees. The majority of patients were in the 60 to 90-year age range. With respect to the waiting time from referral to operation 10% of patients waited less than 5 weeks, 50% waited less than 30 weeks, and 90% waited less than 59 weeks. There was a high level of patient satisfaction with the operation and with hospital care received. Most surgeons found that the gathering and use of data electronically was relevant and easy. The electronic data were more timely, accurate and complete than paper records. CONCLUSION: Electronic point-of-care data collection is appropriate, particularly in high-volume, high-cost surgical interventions such as total joint replacements.

Adult↗
PubMed2000

Intracranial pressure monitoring and outcomes after traumatic brain injury.

OBJECTIVE: Uncontrolled intracranial hypertension after traumatic brain injury (TBI) contributes significantly to the death rate and to poor functional outcome. There is no evidence that intracranial pressure (ICP) monitoring alters the outcome of TBI. The objective of this study was to test the hypothesis that insertion of ICP monitors in patients who have TBI is not associated with a decrease in the death rate. DESIGN: Study of case records. METHODS: The data files from the Ontario Trauma Registry from 1989 to 1995 were examined. Included were all cases with an Injury Severity Score (ISS) greater than 12 from the 14 trauma centres in Ontario. Cases identifying a Maximum Abbreviated Injury Scale score in the head region (MAIS head) greater than 3 were selected for further analysis. Logistic regression analyses were conducted to investigate the relationship between ICP and death. RESULTS: Of 9001 registered cases of TBI, an MAIS head greater than 3 was recorded in 5507. Of these patients, 541 (66.8% male, mean age 34.1 years) had an ICP monitor inserted. Their average ISS was 33.4 and 71.7% survived. There was wide variation among the institutions in the rate of insertion of ICP monitors in these patients (ranging from 0.4% to over 20%). Univariate logistic regression indicated that increased MAIS head, ISS, penetrating trauma and the insertion of an ICP monitor were each associated with an increased death rate. However, multivariate analyses controlling for MAIS head, ISS and injury mechanism indicated that ICP monitoring was associated with significantly improved survival (p < 0.015). CONCLUSIONS: ICP monitor insertion rates vary widely in Ontario's trauma hospitals. The insertion of an ICP monitor is associated with a statistically significant decrease in death rate among patients with severe TBI. This finding strongly supports the need for a prospective randomized trial of management protocols, including ICP monitoring, in patients with severe TBI.

Abbreviated Injury Scale↗
PubMed1998

Metallothionein expression in renal cancer.

OBJECTIVES: To assess metallothionein (MT) expression with immunohistochemical localization in human renal cell carcinoma and to determine whether a possible relationship with the histopathologic findings, tumor grade, or pathologic tumor stage is demonstrable, because MT may have a role in carcinogenesis. METHODS: Archival pathologic specimens and medical records were reviewed for 28 patients with renal cell carcinoma. Immunohistochemical localization of MT was performed with a polyclonal-antibody-to-rat-liver MT, an anti-rabbit IgG linking antibody, and an avidin-biotin horseradish peroxidase complex. Correlation was sought between immunohistochemical data (MT staining intensity, extension, and subcellular site) and clinical data (histologic cell type, tumor grade, and pathologic stage). RESULTS: The mean patient age was 61.7 years (range 42 to 86). The predominant histologic cell type was the clear cell variant. Three, sixteen, and nine tumors were pathologically staged as 1, 2, and 3, respectively. There were 1, 13, 10, and 4 tumors with grades 1, 2, 3, and 4, respectively. Among the independent variables, greater immunoreactivity was observed in Stage 2 tumors (P = 0.028). A significant inverse relationship between tumor grade and MT staining intensity was also observed (P = 0.007). CONCLUSIONS: The inverse relationship in renal cell carcinoma between MT immunoreactivity and tumor grade may indicate a role for MT in tumor growth and dedifferentiation. Increased MT immunoreactivity in lower stage tumors may be related to rapid tumor growth during their growth cycle. Further study is required to elucidate the role of MT in renal cell carcinoma oncogenesis and its possible use as a clinical prognostic parameter.

Adult↗
PubMed1998

Understanding articles describing clinical prediction tools. Evidence Based Medicine in Critical Care Group.

OBJECTIVES: Clinical prediction rules and models are developed by applying statistical techniques to find combinations of predictors that categorize a heterogeneous group of patients into subgroups of risk. Our goal is to teach clinicians how to evaluate the validity, results, and applicability of articles describing clinical prediction tools. CLINICAL EXAMPLE: An article describing a rule to predict the need for intensive care unit care admission in patients presenting to the emergency room with chest pain. RECOMMENDATIONS: Valid clinical prediction tools are developed by completely following up a representative group of patients, by evaluating all potential predictors and testing the independent contribution of each predictor variable, and by ensuring that the outcomes were independent of the predictors. To evaluate the results of an article describing a clinical prediction tool, clinicians need to know what the prediction tool is, how well it categorizes patients into different levels of risk, and what the confidence intervals are around the risk estimates. Valid prediction tools are not applicable in every patient population. Before patient care application, the clinician should ensure that the tool maintains its prediction power in a new sample of patients, that the patients are similar to patients used to test the tool, and that the tool has been shown to improve clinical decision-making. CONCLUSIONS: There has been an increase in the development and validation of clinical prediction rules and models. It is important to evaluate the validity and reliability of these prediction tools before application.

APACHE↗
PubMed1997

Trauma outcome analysis and the development of regional norms.

Early attempts to assess patient outcomes in trauma hospitals included morality reviews and expert panel chart audits. More recently, a statistical methodology combining the Revised Trauma Score and Injury Severity Score has been developed (TRISS). A modification of this methodology--TRISS-like analysis--allows the inclusion of patients who have required endotracheal intubation prior to the time of arrival at the trauma hospital. This study was undertaken to further improve this TRISS-like methodology by developing statistical coefficients based on regional data. It was hypothesized that his would allow the analysis to better identify those hospitals with significantly better worse outcomes than their peers. The Comprehensive Data Set of the Ontario Trauma Registry was accessed, which contains data on severely injured patients from all 11 lead trauma hospitals in the province. Three years' data were obtained, and checked for accuracy and completeness. Analysis was performed using the previously published coefficients. New coefficients were then derived, using regression analysis on the Ontario patient data. 5,258 of 6,389 files were complete and eligible for analysis. TRISS-like analysis resulted in an expected mortality of 21.2% (1115.6/5258) with a z score for the entire province of -14.102. Individual hospital scores were all negative (fewer deaths than expected), and 9/11 hospital scores were < -1.96 (statistically significant). The new coefficients were markedly different from those previously published, and their application resulted in an overall z score of 0.000. Institutional scores ranged from -3.309 to +4.686, with two hospitals < -1.96 and one > +1.96. The old coefficients predicted many more deaths than occurred in all of the hospitals. The new coefficients proved quite accurate overall in predicting outcomes, and identified one institution with significantly more deaths than would have been predicted for other hospitals in the province. Subsequently, a fourth year's data files were obtained, and used as a validation data set. The new coefficients again proved more useful than the original ones.

Humans↗
PubMed1997

Relationship of a new histological categorization of ductal carcinoma in situ of the breast with size and the immunohistochemical expression of p53, c-erb B2, bcl-2, and ki-67.

Ductal carcinoma in situ (DCIS) represents a heterogeneous group of diseases. There is no generally accepted classification for the different cytological and architectural types of DCIS. A recent study (Scott et al, 1995) indicates that over 90% of DCIS can be easily classified into the following five categories: high grade (HG), intermediate grade (IG), low grade (LG), pure micropapillary (M), and pure apocrine (A). The aim of this study was to determine if there is a relationship between lesion size and the immunohistochemical expression of p53, c-erb B2, bcl-2, and ki67 with this reproducible categorization of DCIS. Seventy cases of DCIS diagnosed between 1984 and 1995 were obtained from the Departments of Pathology at two teaching hospitals in London, Ontario. The original sections were reviewed, classified according to Scott et al (1995), and representative sections were cut for immunohistochemical (IHC) studies. IHC stains were scored using a previously described semiquantitative scoring system (Allred et al, 1993). Size was taken from the gross measurement if the lesion was palpable or recorded as the largest dimension, as measured on the histological slide, for nonpalpable cases. Of the 70 DCIS cases, 17 (24.3%) were HG, 23 (32.9%) were IG, 21 (30%) were LG, seven (10%) were pure micropapillary cases, and two (2.9%) were pure apocrine DCIS. The mean size of the DCIS for each subcategory was statistically significantly different (P = .008). In particular, the micropapillary DCIS cases were largest (mean size, 17 mm). The mean immunohistochemical scores for c-erb B2 for each category were also statistically different (P = .007), whereas the mean scores for p53 and ki67 for each category trended toward significance (P = .073, P = .062, respectively). There were no significant differences between bcl-2 mean scores and each subcategory. Size of DCIS and c-erb B2 positivity are known to be associated with more aggressive clinical behavior and more advanced histologic features, respectively. Because this combined histological cytological classification system is predictive of size and c-erb B2 positivity, our results support the clinical relevance of this classification system.

Adult↗
PubMed1996

Lipids and stroke: a paradox resolved.

BACKGROUND: Although dyslipidemia is a well established risk factor for coronary artery disease, its relationship to ischemic cerebrovascular disease has remained unclear, perhaps because of the heterogeneous nature of strokes. METHODS: In a case-control study, we measured the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, serum triglycerides, and lipoprotein(a) levels and determined the apolipoprotein E phenotype and serum ferritin level in 90 consecutive systematically investigated patients with stroke or transient ischemic attack of atherothrombotic origin. Ninety age-, sex-, and community-matched subjects served as controls. RESULTS: Plasma total cholesterol (5.99 vs 5.45 mmol/L [232 vs 211 mg/dL], P=.003), low-density lipoprotein cholesterol (3.96 vs 3.45 mmol/L [153 vs 133 mg/dL], P=.004), and serum triglyceride (2.09 vs 1.82 mmol/L [8] vs 70 mg/dL], P=.03) levels were significantly higher among the patients with atherothrombotic strokes and transient ischemic attacks than among the control subjects. The inverse was true for high-density lipoprotein cholesterol (1.07 vs 1.18 mmol/L [41 vs 46 mg/dL], P=.02) levels. No significant differences were found in lipoprotein(a) levels or in the distribution of apolipoprotein E phenotypes or allele frequency. Serum ferritin levels did not differ significantly between patients and control subjects. CONCLUSIONS: Elevated low-density lipoprotein cholesterol and triglyceride levels are significant independent risk factors in patients with proven atherothrombotic cerebrovascular disease manifesting as stroke or transient ischemic attack. The level of stored serum iron, as reflected by serum ferritin levels, does not correlate with the presence of atherothrombotic cerebrovascular or coronary disease.

Aged↗
PubMed1996

Patients' preferences for therapy in advanced epithelial ovarian cancer: development, testing, and application of a bedside decision instrument.

The objective of this study was to determine a patient's preference for treatment in the poor prognostic situation of advanced epithelial ovarian cancer. A standardized method of information transfer was developed and pretested for feasibility, acceptability, comprehension, interobserver reliability, and validity. The Decision Board (DB) describes to the patient who has completed surgery for suboptimally debulked ovarian cancer two treatment options, their potential side effects, and possible outcomes. The psychometric properties of the DB were determined in 37 volunteers without cancer and 11 women following first-line chemotherapy for ovarian cancer. The Board was then administered to 12 patients with stage IIIc and IV ovarian cancer at the point of deciding future chemotherapy. The feasibility of presenting poor prognostic information, patient comprehension in an emotionally charged situation, and her treatment choice were determined. Observation of patient-physician interviews revealed that survival information is not usually discussed on the initial consultation. Using the DB, it was feasible to provide survival information to 98% of the healthy women. Comprehension was high, with 96% of the questions being correctly answered. Interobserver reliability was high (kappa = 1.00). The construct that hypothesized that understanding information is a determinant of choice was verified, as 95.2% of women had predictable shifts in expressed preference. The strength of preference in healthy women was statistically significantly higher for Plan B (paclitaxel-cisplatin) than for Plan A (cisplatin-cyclophosphamide) (P < 0.001). The method of presenting survival information (median survival versus percentage survival at 3.5 years) influenced choice (P < 0.04). At the point of decision making, 33% of patients with advanced ovarian cancer chose Plan A and 67% chose Plan B. All volunteers and patients stated that they wanted to be fully informed of the choices of therapy for their disease and to be involved in treatment decisions. The DB is a reliable and valid method for sharing information about advanced ovarian cancer with patients. At the point of deciding first-line chemotherapy in this poor prognostic situation, patients still value survival more highly than the quality of life during chemotherapy.

Adult↗
PubMed1996

The predictive power of semiquantitative immunohistochemical assessment of p53 and c-erb B-2 in lymph node-negative breast cancer.

A series of 107 lymph node-negative (LNN) breast cancers was stained immunohistochemically with a combination of p53 and c-erb B-2. The immunohistochemical results were semiquantitated using a previously described system by Allred et al. p53 immunopositive cases were further screened for DNA mutations by the polymerase chain reaction-single-strand conformation polymorphism method (PCR-SSCP). Three representative cases showing mobility shifts were directly sequenced. One hundred of 103 invasive carcinomas were of no special type (infiltrating ductal carcinomas not otherwise specified). The three special type carcinomas included a tubular carcinoma, a classic infiltrating lobular carcinoma, and a mucinous carcinoma. Twenty-six patients (25.2%) had grade I carcinomas, and 77 patients (75%) had grade 2 or 3 carcinomas. There were four cases composed predominantly of ductal carcinoma in situ (DCIS) with foci of microinvasion. Twenty-seven of 107 patients (25%) died of disease. All those who died had grade 2 or 3 tumors. Univariate analysis showed that p53 and c-erb B-2 positivity (score > 6) were associated with a decreased overall survival (OS) (P = .0012 and P = .010, respectively), and a decreased disease-free survival (DFS) (P = .0009 and P = .027, respectively). The multivariate model selected these two variables as the best predictors of both OS and DFS (all P = or < .01). These results suggest that semiquantitative immunohistochemical analysis of p53 and c-erb B-2 provides prognostic information in LNN disease.

Adult↗
PubMed1996

An evaluation of Ontario trauma outcomes and the development of regional norms for Trauma and Injury Severity Score (TRISS) analysis.

Outcomes analysis of patient care programs has become increasingly necessary for a variety of reasons in recent years. This has been particularly true for trauma programs. The Trauma and Injury Severity Score (TRISS) methodology was developed for this purpose in the context of the Major Trauma Outcome Study (MTOS). It provides an estimate of the probability of survival for individual patients, based on anatomic, physiologic, and etiologic factors. In addition, it allows hospitals and groups of hospitals to compare survival rates with other hospitals submitting data to the data base. However, the published coefficients for TRISS analysis have been derived from the MTOS data base. Patterns of practice, time to treatment, and other variables may be significantly different in other jurisdictions. To compare outcomes among similar hospitals within the province of Ontario, Canada, a regression analysis was performed to develop TRISS coefficients specific to the province. Data were obtained from the 12 trauma centers in the province treating the most severely injured patients (Injury Severity Score > 12). A total of 3,880 cases were eligible for TRISS analysis, over a 3-year period. Of these, 3,672 were patients with blunt trauma, and 208 were victims of penetrating injury. Standard TRISS analysis of the patients with blunt trauma revealed z scores ranging from -10.260 to +1.849, with a mean of -6.648. Four centers had negative z scores that were significant (an absolute value of > 1.96 is considered statistically significant). Using Ontario TRISS coefficients, z scores ranged from -4.125 to +2.782, with a mean of 0.000. Four scores were significant with the Ontario coefficients, only one of which had been significant using the MTOS norms. The other three z scores were all positive, indicating more deaths than would have been predicted, but they were not significant when compared to the MTOS norms. The mean was also, of course, no longer significant. The area under the receiver operating characteristic curve analysis was strongly positive, and the Hosmer-Lemeshow Goodness-of-Fit analysis indicated good calibration. The new coefficients were subsequently validated by applying them to a subsequent year's data from patient records that did not form part of the original data set. This resulted in slightly improved z scores overall, and in most of the hospitals. This use of regional norms allows comparison with outcomes of patients cared for in hospitals within the same jurisdiction that are more similar to one another than to those in the MTOS, and helps to identify unexpected outcomes and outliers.

Evaluation Studies as Topic↗
PubMed1996

Hyperdynamic sepsis depresses circulatory compensation to normovolemic anemia in conscious rats.

This study was designed to determine whether sepsis modifies the ability to preserve vital organ O2 delivery (QO2) across a clinically relevant range of hematocrits. Ninety rats were randomly allocated to cecal ligation and perforation (CLP) or a sham (Sham) procedure. With the use of rat plasma, rat whole blood, or packed rat red blood cells, respectively, randomization into three different hematocrit subgroups followed: low (21-28%), middle (33-40%), and high (45-52%). Organ blood flow values (Q) were measured by the radioactive microsphere technique, and organ QO2 values were calculated. Twenty-four hours after laparotomy, the hematocrit grouping had not modified the interorgan distribution of Q or QO2 in either the CLP or Sham rats. To characterize overall metabolic O2 reserve, rats were then exposed to hypoxia (inspired O2 fraction, 0.08) for 20 min. Whereas cardiac output increased significantly during hypoxia in all experimental groups, myocardial QO2 failed to increase in the low hematocrit Sham subgroup and fell significantly in both the middle- and low-hematocrit CLP subgroups. There was also a lesser redistribution of QO2 away from the small intestine in the low-hematocrit compared with the high-hematocrit CLP subgroup. We conclude that myocardial QO2 is more effectively maintained in septic hypoxic rats if the hematocrit is maintained at levels >45%.

Anemia↗
PubMed1981

Cerebrovascular mechanisms in perinatal asphyxia: the role of vasogenic brain edema.

Previous studies from our laboratory have demonstrated penetration of Evan's blue dye into the brain in profound fetal asphyxia, suggesting that vasogenic brain edema (BE) might be an immediate contributing factor in asphyxial brain injury. We modified the 125I-labeled albumin method of Pappius and McCann to quantitate vasogenic BE after acute fetal asphyxia. With 51Cr-labeled red cells to measure intravascular volume, and 125I-labeled albumin to measure total tissue plasma, the equivalent extra vascular plasma volume, i.e., vasogenic BE, was calculated. Twenty chronically prepared animals were studied, six nonasphyxiated controls and 14 asphyxiated (of which sex term animals were normotensive and five term and three premature animals were hypertensive during asphyxia). No difference in extra vascular plasma volume was found between asphyxiated and control animals in any of four brain regions. We conclude that, although blood brain barrier function might be impaired, vasogenic BE is not quantitatively significant immediately after severe fetal asphyxia.

Animals↗
PubMedDate not supplied

Using the Vista 350 telephone to communicate the results of home monitoring of diabetes mellitus to a central database and to provide feedback.

PURPOSE: Self-monitoring of blood glucose has become routine practice in the management of diabetes mellitus. When all the data is complete, however, the amount of information to be taken into account when making therapeutic decisions becomes overwhelming not only for the patient but for the healthcare provider. Computers excel at processing large amounts of information quickly and impassively, which makes them potentially helpful for collating and communicating the data in a manner that facilitates decision-making by patient and healthcare provider. This should in turn improve control and help prevent acute and chronic complications. METHOD: Using the Vista 350 telephone, we have developed a system that enables patients with diabetes to record home monitoring data to a central database and receive feedback summaries. A small trial was conducted to determine if the Vista 350 telephone is an acceptable and feasible method to communicate the results of home monitoring of diabetes mellitus to a central database and receive feedback summaries. A total of 35 volunteers with insulin-requiring diabetes mellitus in the London area were randomly allocated to either use the Vista 350 phone for 6 months, or to a control group that continued to use traditional methods for recording home monitoring data. RESULTS: 33 of the 35 patients enrolled completed the trial. All 16 patients who began using the phone continued to do so for 6 months confirming the feasibility of the system. Questionnaires completed at 3 and 6 months confirmed the Vista 350 telephone system to be acceptable to the subjects. The results will enable some minor modifications to be made to the telephone system before a larger definitive trial, designed to determine the effect on diabetes control, is conducted later this year.

Blood Glucose Self-Monitoring↗