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Biomedical subjects

T C Stewart

Publications and source records attributed to T C Stewart.

16 recordsLinked to original sources
PubMed2001

Pediatric trauma registries: the foundation of quality care.

BACKGROUND/PURPOSE: Traumatic injuries cause substantial morbidity and mortality in children. Trauma registries are essential to assess and improve standards of trauma care. An interprovincial study of pediatric trauma between 6 centers across Canada who use identical software components was completed. METHODS: Data were collected from April 1, 1995 to December 31, 1998 for children aged 1 day to 17 years with an injury severity score of > or = 12. Cause of injury, injury time and day, gender, age, injury scores, length of hospital stay, and outcomes were compared. RESULTS: A total of 1,276 patients were included. Mean age was 10.3 +/- 5.6 years. Motor vehicle collisions were the most common mechanism of injury (56%). Boys were more often injured (66%; P < .05). Injuries occurred mainly between 1600 and 2400 hours (P < .0001). Mean hospital stay was 11.5 +/- 16.6 days. The longest stays in the hospital were among those who had an abdominal abbreviated injury score (AIS) of 1 (P < or = .03). Patients with similar injury severities remained twice as long in Winnipeg Children's Hospital (hospital 5), hospital 2, and hospital 6 as compared with patients in hospital 3 (P < .05). Differences existed in discharge placement between hospitals (P < .0001). CONCLUSIONS: This study was the first to compare pediatric patients in multiple Canadian centers using identical trauma registries. Variations in length of stay and discharge placements between hospitals were identified. Further analysis of data in the registries may clarify these differences and serve as a foundation for hospitals to improve the quality of patient care.

Accidents, Traffic↗
PubMed2000

Open or closed diagnostic peritoneal lavage for abdominal trauma? A meta-analysis.

OBJECTIVES: To perform a meta-analysis of prospective, randomized controlled trials comparing the closed and open technique of diagnostic peritoneal lavage (DPL) in trauma patients to determine whether there are any difference in outcomes. METHODS: A search of MEDLINE database of English language articles published from 1977 to 1999 was conducted by using the terms diagnostic peritoneal lavage, trauma, and randomized controlled trials. A manual search and Cochrane Library database search was also conducted. Seven randomized controlled trials, including a total of 1,126 patients were identified that compared closed versus open technique. Two reviewers assessed the trials independently. Trial quality was critically appraised by using the Jadad Instrument, a validated published quality scale. Data extraction of major complications, technical difficulties, procedure times, and false-negative and false-positive rates was carried out. The fixed effects model was used for statistical analysis. The Peto odds ratio (OR), weighted mean differences and 95% confidence intervals (95% CI) were calculated. RESULTS: The overall quality of studies was poor (mean, 2.4/7). Major complications did not differ significantly between closed versus open technique (OR, 0.65; 95% CI, 0.15 to 2.92. Technical failures and difficulties were significantly higher in the closed group, i.e., OR 4.33 (95% CI, 1.96 to 9.56) and OR 4.19 (95% CI, 2.842 to 6.19), respectively. Accuracy of closed and open DPL was comparable with no difference in false-negative or false-positive rates between the two techniques. Procedure time was consistently lower in the closed technique. CONCLUSIONS: The closed DPL technique is comparable to the standard open DPL technique in terms of accuracy and major complications. The advantage of reduced time to perform the closed DPL is offset by the increased technical difficulties and failures of this group. Therefore, any significant benefit of routine closed DPL in improving outcomes can be excluded with more confidence based on pooled data than by the individual trials alone.

Abdominal Injuries↗
PubMed2000

Epidemiology of maxillofacial injuries at trauma hospitals in Ontario, Canada, between 1992 and 1997.

BACKGROUND: The purpose of this study was to review the epidemiology of maxillofacial skeletal injuries in severely injured patients admitted to trauma hospitals in Ontario, Canada, with an Injury Severity Score > 12. METHODS: The Ontario Trauma Registry was accessed to examine the epidemiology of maxillofacial skeletal injuries in severely injured patients treated at 12 trauma hospitals in the province of Ontario, Canada, between 1992 and 1997. Data were collected prospectively, and a descriptive analysis was performed to determine the pattern of maxillofacial injuries, including patient age, sex distribution, etiology of injury, time of injury, and injury profile. RESULTS: There were 2,969 patients that met the inclusion criteria. The median age was 25 years, and men were injured at a 3:1 ratio over women. Most severely injured patients with maxillofacial fractures were injured as a result of motor vehicle collision (70%), with only 33% of the patients restrained with a seat-belt. The temporal distribution of injuries showed that most injuries occurred during evening hours, on weekends, and in the summer. The largest number of fractures was found in the maxilla and orbital bones. The Injury Severity Score of the patients in this study ranged from 13 to 75, with a median of 25. The injury most commonly associated with maxillofacial fractures was injury to the head and neck area. Of patients with injury to the head and neck, most had an altered level of consciousness or injuries to the skull, brain, or cranial vessels. CONCLUSION: Many severely injured patients have maxillofacial injuries. Long-term collection of epidemiologic data regarding maxillofacial fractures is important for the evaluation of existing preventative measures and useful in the development of new methods of injury prevention. Furthermore, insight into the epidemiology of facial fractures and concomitant injuries is an integral component in evaluating the quality of patient care, developing optimal treatment regimens, and making decisions regarding appropriate resource and manpower allocations.

Adolescent↗
PubMed2000

Autopsies and death certification in deaths due to blunt trauma: what are we missing?

OBJECTIVES: To determine the frequency, body region and severity of injuries missed by the clinical team in patients who die of blunt trauma, and to examine the accuracy of the cause of death as recorded on death certificates. DESIGN: A retrospective review. SETTING: London Health Sciences Centre, London, Ont. PATIENTS: One hundred and eight deaths due to blunt trauma occurring during the period Apr. 1, 1991, to Mar. 31, 1997. Two groups were considered: clinically significant missed injuries were identified by comparing patient charts only (group 1) and more detailed injury lists from the autopsies and charts of the patients (group 2). OUTCOME MEASURES: Chart and autopsy findings. RESULTS: Of the 108 patients, 78 (72%) were male, and they had a median age of 39 years (range from 2 to 90 years). The most common cause of death was neurologic injury (27%), followed by sepsis (17%) and hemorrhage (15%). There was disagreement between the treating physicians and the causes of death listed on the death certificate in 40% of cases and with the coroner in 7% of cases. Seventy-seven clinically significant injuries were missed in 51 (47%) of the 108 patient deaths. Injuries were missed in 29% of inhospital deaths and 100% of emergency department deaths. Abdominal and head injuries accounted for 43% and 34% of the missed injuries, respectively. CONCLUSIONS: The information contained on the death certificate can be misleading. Health care planners utilizing this data may draw inaccurate conclusions regarding causes of death, which may have an impact on trauma system development. Missed injuries continue to be a concern in the management of patients with major blunt trauma.

Adolescent↗
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↗
PubMed1996

An evaluation of patient outcomes comparing trauma team activated versus trauma team not activated using TRISS analysis. Trauma and Injury Severity Score.

OBJECTIVE: The purpose of this study was to compare the outcomes of trauma patients with an Injury Severity Score (ISS) > 12 who had the trauma team involved (TTA) in their resuscitative care to those that did not (TTNA). SETTING: Level I regional trauma center teaching hospital with university affiliation. METHODS: All trauma patients admitted between July 1, 1991 and August 31, 1994 with an ISS > 12 were identified through the trauma registry. Burn patients, those who suffered their injury > 24 hours before admission, and deaths in the emergency room were excluded from analysis. The TRISS methodology, which offers a standard approval for evaluating outcomes for different populations of trauma patients, was used to determine whether there was a difference in outcomes between the two groups. To include patients who arrived at the trauma center intubated, a Trauma and Injury Severity Score (TRISS)-like analysis was also conducted on this patient population. MAIN RESULTS: A total of 640 patients were identified; 174 (65.2%) in the TTA group and 223 (34.8%) in the TTNA group. A total of 448 (70%) were eligible for TRISS analysis and 574 (89.7%) were eligible for TRISS-like analysis. Using the TRISS analysis, the TTA group had a Z statistic of 3.36 yielding a W score of 4.27. This compared to the TTNA group whose Z statistic was 0.30. Using the TRISS-like logistic regression equation, the TTA group had a Z statistic of 6.50, yielding a W score of 8.60 compared with the TTNA group whose Z statistic was 0.88. After controlling for differences in the demographics of the two groups, the TTA still had consistently higher Z scores. CONCLUSION: In a Level I trauma center, the outcomes of trauma patients with an ISS > 12 are statistically significantly better if the trauma team is activated than if the patients are managed on an individual service-by-service basis.

Adult↗
PubMed1995

An evaluation of patient outcomes before and after trauma center designation using Trauma and Injury Severity Score analysis.

In June 1990, the Ministry of Health designated 11 hospitals throughout Ontario to be lead hospitals in trauma care. An integral part of a trauma system is the evaluation of care, in particular, outcome of the trauma patients. The Trauma and Injury Severity Score (TRISS) methodology, which offers a standard approach for evaluating outcomes for different populations of trauma patients, was used to determine if there was an improvement in outcomes after the designation of trauma centers of patients involved in motor vehicle crashes (ICD-9-CM, E810.0-825.9), with an Injury Severity Score > 12 for two 12-month periods: one predesignation (1989/1990) and one postdesignation (1992/1993). The Revised Trauma Score, Injury Severity Score, age, and outcome were calculated or abstracted from the hospital chart of each patient at the trauma center. The probability of survival of each patient, the z- and W-statistics of both years were calculated. A measurable improvement was shown in z-statistics between the 2 years from z = -0.40 predesignation to z = +0.72 postdesignation. When the bias introduced by patients intubated before arrival at the trauma center being excluded from TRISS analysis was removed, using a TRISS-like (as per Offner et al: J. Trauma 32:32, 1992) logistic regression equation that allows analysis of intubated patients, the improvement was even greater, with z = +1.34 predesignation and z = +2.97 postdesignation. Only the statistically significant z-score of the postdesignated year required the W-score to be calculated, W = +5.60.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1993

In vitro interaction of heavy metals with ouabain receptors in rat brain microsomes.

This study investigates the influence of heavy metals on ouabain-binding in presence of thiol (sulfhydryl) compounds. The data on in vitro effects of mercury (Hg), lead (Pb) and cadmium (Cd) showed significant inhibition of 3H-ouabain binding to microsomal membrane in a concentration-dependent manner. Maximum inhibition of 3H-ouabain binding was observed at 1 microM for Hg and 100 microM each for Pb and Cd. Preincubation with monothiol (L-cysteine or glutathione) or dithiol (dithiothreitol) protected inhibition of 3H-ouabain binding to the membranes by Hg or Pb. Dithiol but not monothiols partially protected Cd-inhibition. The present data confirm that the heavy metals interact with ouabain receptors in a manner similar to SH-blocking agents and protection of metal-inhibited 3H-ouabain binding by thiol compounds is metal specific.

Animals↗
PubMed1991

Effects of lead on pH and temperature-dependent substrate-activation kinetics of ATPase system and its protection by thiol compounds in rat brain.

Lead (Pb) inhibited the activities of Na(+)-K+ ATPase (IC50 = 2.0 x 10(-6) M), K(+)-Para-Nitrophenyl phosphatase (PNPPase) (IC50 = 3.5 x 10(-6) M) and [3H]-ouabain binding (IC50 = 4.0 x 10(-5) M) in rat brain P2 fraction. A variable temperature or pH significantly elevated the inhibition of Na(+)-K+ ATPase by Pb in buffered acidic, neutral and alkaline pH ranges. Noncompetitive inhibition with respect to activation of Na(+)-K+ ATPase by ATP was indicated by a variation in Vmax values with no significant changes in Km values at any temperature studied. In the presence of Pb, for Na(+)-K+ ATPase at pH 6.5 and 8.5, Vmax was decreased with an increase in Km values suggesting a mixed type of inhibition. Sulfhydryl agents such as dithiothreitol (DTT) and cysteine (Cyst), but not glutathione (GSH) offered varied levels of protection against Pb-inhibition of Na(+)-K+ ATPase at pH 7.5 and 8.5. The present data suggest that inhibition of Na(+)-K+ ATPase by Pb is both temperature and pH-dependent. These results also indicate that Pb inhibited Na(+)-K+ ATPase by interfering with phosphorylation of enzyme molecule and dephosphorylation of the enzyme-phosphoryl complex and exerted an effect similar to that of SH-blocking agents.

4-Nitrophenylphosphatase↗
PubMed1983

Statistical comparison of blood glucose as determined by several test-strip procedures and by a hexokinase procedure.

We report a new statistical tool for comparing several dry-reagent strip procedures for whole blood glucose, which produce data in both digital and ordinal form, with results by the well-studied hexokinase-glucose-6-phosphate dehydrogenase procedure coupled to NAD+-NADH. Our use of "ordinal comparison unit" allows for a more equitable comparison of such data. These strip procedures produce biases of -2.21 to 1.74 ordinal comparison units over the range of glucose values corresponding to hypoglycemia and hyperglycemia, as compared with results by the hexokinase procedure, but they are essentially equivalent when compared with each other.

Blood Glucose↗
PubMed1976

Evaluation of a reagent-strip method for glucose in whole blood, as compared with a hexokinase method.

The hexokinase method (I) for glucose in biological fluids, proposed by the FDA as a potential national standard method, is compared with the Eyetone/Dextrostix/Control method (II) for measurement of glucose in whole blood. I used a new, two-step calibration procedure based on a 1.30 g/liter standard for the II system. The correlation coefficient for results by the two methods was 0.99 for 142 assays in duplicate. Recovery values were near 100% (I, range 100.0 to 106.2%; II, range 100.8 to 105.1%), and the coefficients of variation were respectively +/- 4.1% and +/- 4.5%. Considering the close correlation between the two methods, together with the simplicity, speed, and convenience of II, I conclude that it has great clinical utility, particularly in emergency situations. The precision and accuracy of II depends greatly on proper calibration and control procedures and on adequate training of the operator.

Bilirubin↗
PubMedDate not supplied

Effect of prior, low-level cadmium exposure in vivo on metallothionein expression in cultured lymphocytes.

Exposure to cadmium (Cd) is currently monitored by measurement of the metal in blood or urine, or by observation of excreted compounds such as beta 2-microglobulin or N-acetyl-beta-D-glucose. Whilst these approaches are useful for the detection of acute exposure to Cd, their applicability in the management of long-term, low-level exposure is less clear. Metallothioneins are ubiquitous proteins that are synthesized in response to heavy metal ions and may offer themselves as being a biologically sensitive indicator of Cd exposure. We have examined both basal and Cd-induced metallothionein mRNA levels in cultured lymphocytes from groups with different exposures to Cd, attempting to assess their potential as an indicator of Cd exposure and the suitability of such an assay for routine analysis. We found that induced metallothionein mRNA levels, rather than basal mRNA levels, increased in groups known to have received elevated body burdens of Cd, although these increases were not significant between groups. There was, however, a significant correlation between induced metallothionein mRNA levels and urinary beta 2-microglobulin. These results suggest that further work on the in vitro lymphocyte response to Cd as a diagnostic tool is warranted.

Adult↗