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Biomedical subjects

M K Vandervoort

Publications and source records attributed to M K Vandervoort.

18 recordsLinked to original sources
PubMed2001

Evaluation of portable bladder ultrasound: accuracy and effect on nursing practice in an acute care neuroscience unit.

The purpose of this evaluation was to determine the accuracy of a portable ultrasound instrument in assessing bladder volume in an acute care neuroscience population and the effect of ultrasound assessment on nursing practice in an acute care neuroscience unit. In a 6-week prospective evaluation, 105 paired ultrasound measurements were performed by 45 nurses on 30 patients suspected to be retaining urine. Sixty-seven catheterizations were performed, and volumes were compared with corresponding ultrasound readings. The first ultrasound volume readings slightly underestimated the catheterized volumes, but the volumes from the first ultrasound readings and the catheterized volumes were highly correlated. Volume readings from a second ultrasound, the average of the first and second ultrasound readings, and the higher of the two ultrasound readings did not add to the ability of the ultrasound instrument to predict catheterized volumes. Patient age and gender did not change the relationship between ultrasound and catheterized volumes. The ultrasound assessment changed nursing practice in 51% of the instances; the most common change (32%) was that nurses did not catheterize the patient. The ultrasound assessment did not change nursing practice in 49% of the instances; the most common reason (41%) was that the ultrasound confirmed the need to catheterize the patient. The instrument was therefore judged to be an accurate and reliable tool that changed nursing practice in an acute care neuroscience unit.

Acute Disease↗
PubMed2000

Treatment and outcomes of community-acquired pneumonia at Canadian hospitals.

BACKGROUND: Community-acquired pneumonia is a common disease with a large economic burden. We assessed clinical practices and outcomes among patients with community-acquired pneumonia admitted to Canadian hospitals. METHODS: A total of 20 hospitals (11 teaching and 9 community) participated. Data from the charts of adults admitted during November 1996, January 1997 and March 1997 were reviewed to determine length of stay (LOS), admission to an intensive care unit and 30-day in-hospital mortality. Multivariate analyses examined sources of variability in LOS. The type and duration of antibiotic therapy and the proportion of patients who were treated according to clinical practice guidelines were determined. RESULTS: A total of 858 eligible patients were identified; their mean age was 69.4 (standard deviation 17.7) years. The overall median LOS was 7.0 days (interquartile range [IQR] 4.0-11.0 days); the median LOS ranged from 5.0 to 9.0 days across hospitals (IQR 6.0-7.8 days). Only 22% of the variability in LOS could be explained by known factors (disease severity 12%; presence of chronic obstructive lung disease or bacterial cause for the pneumonia 2%; hospital site 7%). The overall 30-day mortality was 14.1% (95% confidence interval [CI] 11.8%-16.6%); 13.6% of the patients were admitted to an intensive care unit (95% CI 11.4%-16.1%). The median duration of intravenous antibiotic therapy was 5 days (range 3.0-6.5 days across hospitals). Although 79.8% of patients received treatment according to clinical practice guidelines, the rate of compliance with the guidelines ranged from 47.9% to 100% across hospitals. INTERPRETATION: Considerable heterogeneity exists in the management of community-acquired pneumonia at Canadian hospitals, the causes of which are poorly understood.

Adult↗
PubMed2000

A controlled trial of a critical pathway for treatment of community-acquired pneumonia. CAPITAL Study Investigators. Community-Acquired Pneumonia Intervention Trial Assessing Levofloxacin.

CONTEXT: Large variations exist among hospitals in the use of treatment resources for community-acquired pneumonia (CAP). Lack of a common approach to the diagnosis and treatment of CAP has been cited as an explanation for these variations. OBJECTIVE: To determine if use of a critical pathway improves the efficiency of treatment for CAP without compromising the well-being of patients. DESIGN: Multicenter controlled clinical trial with cluster randomization and up to 6 weeks of follow-up. SETTING: Nineteen teaching and community hospitals in Canada. PATIENTS: A total of 1743 patients with CAP presenting to the emergency department at 1 of the participating institutions between January 1 and July 31, 1998. INTERVENTION: Hospitals were assigned to continue conventional management (n = 10) or implement the critical pathway (n = 9), which consisted of a clinical prediction rule to guide the admission decision, levofloxacin therapy, and practice guidelines. MAIN OUTCOME MEASURES: Effectiveness of the critical pathway, as measured by health-related quality of life on the Short-Form 36 Physical Component Summary (SF-36 PCS) scale at 6 weeks; and resource utilization, as measured by the number of bed days per patient managed (BDPM). RESULTS: Quality of life and the occurrence of complications, readmission, and mortality were not different for the 2 strategies; the 1-sided 95% confidence limit of the between-group difference in the SF-36 PCS change score was 2.4 points, which was within a predefined 3-point boundary for equivalence. Pathway use was associated with a 1.7-day reduction in BDPM (4.4 vs 6.1 days; P = .04) and an 18% decrease in the admission of low-risk patients (31% vs 49%; P = .01). Although inpatients at critical pathway hospitals had more severe disease, they required 1.7 fewer days of intravenous therapy (4.6 vs 6.3 days; P = .01) and were more likely to receive treatment with a single class of antibiotic (64% vs 27%; P<.001). CONCLUSION: In this study, implementation of a critical pathway reduced the use of institutional resources without causing adverse effects on the well-being of patients.

Aged↗
PubMed1996

Plasma-exchange therapy in chronic inflammatory demyelinating polyneuropathy. A double-blind, sham-controlled, cross-over study.

Eighteen patients with definite, untreated chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) of chronic progressive (nine patients) or relapsing course (nine patients) were randomized prospectively to receive 10 plasma-exchange (PE) or sham plasma-exchange (SPE) treatments over 4 weeks in a double-blind trial. After a wash-out period of 5 weeks or when they returned to baseline scores, patients were crossed over to the alternate treatments. Neurological function was assessed serially using a quantitative neurological disability score (NDS), a functional clinical grade (CG) and grip strength (GS) measurements. Electrophysiological studies were done at the beginning and end of each treatment. A primary 'intention to treat' analysis showed significant improvement with PE in all clinical outcome measures: NDS by 38 points, P < 0.001; CG by 1.6 points, P < 0.001; GS by +13 kg, P < 0.003 and in selected electrophysiological measurements, sigma proximal CMAP, P < 0.01; sigma motor conduction velocities, P < 0.006; sigma distal motor latencies, P < 0.01. Fifteen patients completed the trial and of those, 12 patients (80%) improved substantially with PE; i.e. five out of seven patients with chronic progressive course and seven out of eight patients with relapsing CIDP improved. There were three drop-outs; one patient lost venous access; one patient suffered a stroke and one patient left the trial to receive open treatment elsewhere. The improvement in motor functions correlated with the electrophysiological data, i.e. with improved motor conduction velocities and reversal of conduction block. Eight of 12 PE responders (66%) relapsed within 7-14 days after stopping PE. All improved with subsequent open label PE; all but two patients required long-term immunosuppressive drug therapy for stabilization. The PE non-responders improved with prednisone. We conclude that PE is a very effective adjuvant therapy for CIDP of both chronic progressive and relapsing course; concurrent immunosuppressive drug treatment is required. Exchange treatments should be given two to three times per week until improvement is established; the treatment frequency should then be tapered over several months.

Adolescent↗
PubMed1994

The impact of blinding on the results of a randomized, placebo-controlled multiple sclerosis clinical trial.

In the randomized, placebo-controlled, physician-blinded Canadian cooperative trial of cyclophosphamide and plasma exchange, neither active treatment regimens (group I: i.v. cyclophosphamide and prednisone; group II: weekly plasma exchange, oral cyclophosphamide, and prednisone) were superior to placebo (group III: sham plasma exchange and placebo medications) using the blinded, evaluating neurologists' assessments of disease course (primary analysis). All patients were examined by both a blinded and an unblinded neurologist at each assessment in this trial. We compared the blinded and unblinded neurologists' judgment of treatment response and analyzed the clinical behavior of patients who correctly guessed their treatment. The unblinded (but not the blinded) neurologists' scores demonstrated an apparent treatment benefit at 6, 12, and 24 months for the group II patients (not group I or placebo; p < 0.05, two-tailed). There were no significant differences in the time to treatment failure or in the proportions of patients improved, stable, or worse between the group II and group III patients who correctly guessed their treatment assignments and those who did not. Physician blinding prevented an erroneous conclusion about treatment efficacy (false positive, type 1 error).

Cyclophosphamide↗
PubMed1993

An open-trial evaluation of mitoxantrone in the treatment of progressive MS.

We treated 13 patients with progressive MS with mitoxantrone. All patients received a standard IV dose of mitoxantrone (8 mg/m2) every 3 weeks for a total of seven infusions, with dosage adjustments depending on the hematologic profile at the nadir. The treatment was well tolerated, with the most common side effect being mild nausea. Four of seven women developed transient secondary amenorrhea. The postenrollment clinical behavior of these patients was generally more favorable than during the 18 months prior to enrollment (only three of 13 patients developed an increase in the Expanded Disability Status Scale of more than 0.5 points), suggesting a possible treatment effect, but comparison with two historical control groups (both the active and placebo groups from the Canadian Cooperative Trial of Cyclophosphamide and Plasma Exchange) does not suggest that mitoxantrone was efficacious. Eight of 12 patients had evidence of MRI activity on 13 of 29 follow-up visits. This small, open-labeled pilot study did not provide strong support for proceeding with a randomized, controlled trial of this dosage regimen of mitoxantrone in patients with progressive MS.

Adult↗
PubMed1992

Serial cranial and spinal cord magnetic resonance imaging in multiple sclerosis.

Twenty-nine mildly disabled patients with multiple sclerosis underwent serial clinical and magnetic resonance imaging (MRI) evaluations (pre- and postgadolinium cranial and spinal cord MRI) on at least 3 occasions at 13-week intervals and during periods of suspected relapse. Using clinical judgment of the presence of recent active disease as the gold standard, combined MRI studies confirmed the clinical impression of active disease in 93% of follow-up visits (sensitivity) and the absence of active MS in 63% of follow-up visits (specificity). None of the cranial and spinal MRI-detected abnormalities disappeared. Gadolinium administration particularly increased the yield of spinal MRI. Cranial MRI alone detected 80% of the MRI-active visits. Clinical and MRI concordance was significantly better for the presence of recent disease activity than for the anatomical localization of the presumed site of activity. MRI evidence of apparent ongoing disease activity was seen more frequently in patients believed to have active multiple sclerosis in the preceding year (13 of 21) than in patients who had been in clinical remission for at least the 2 preceding years (2 of 8). Although clinical evidence of new disease activity was much less common in patients with active, chronic-progressive disease (1 of 8) than in patients with active, relapsing disease (9 of 13), the proportion of patients with either infrequent relapses, frequent relapses, or slow chronic-progressive disease in the preceding year in whom MRI activity developed and the pattern of this new MRI activity was similar between these types of active patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1990

NMR studies in experimental allergic encephalomyelitis: factors which contribute to T1 and T2 values.

To determine the factors which may alter NMR relaxation times in multiple sclerosis (MS) lesions we measured the proton T1 and T2, specific gravity (SG), and histology in the central nervous system (CNS; 13-19 levels per animal) in the myelin basic protein (MBP) and CNS-induced acute and relapsing EAE models in 44 juvenile Hartley guinea pigs. In the MBP model, T1 is unchanged but T2 is prolonged before symptoms and pathological changes occur. T2 remains prolonged during the acute phase of MBP-induced EAE. In the acute CNS model, T1 and T2 were not different from control despite advanced pathological changes of inflammation and demyelination and changes in specific gravity, indicating a marked change in tissue water content. No single variable, pathological or SG, could predict T1 or T2 values in the CNS-induced model. In active disease in the MBP model, when edema occurs in the presence or absence of parenchymal infiltration, T2 values are increased. However, as the factors which influence tissue NMR characteristics are complex in these MS models, it is likely difficult to infer specific pathological events from MRI findings in patients with MS.

Acute Disease↗
PubMed1990

Interrater variability with the Expanded Disability Status Scale (EDSS) and Functional Systems (FS) in a multiple sclerosis clinical trial. The Canadian Cooperation MS Study Group.

We describe the interrater variability in the Expanded Disability Status Scale (EDSS) and Functional Systems (FS) in a multiple sclerosis clinical trial. Two physicians blinded to their previous assessments and to each other's scores consecutively examined 168 patients (545 paired examinations). Perfect agreement on the assignment of the disability scores ranged from 48% (cerebellar functional group) to 69% (EDSS and pyramidal functional group). Only 31% to 62% of this agreement occurred independently of that expected by chance (kappa). With the exception of the cerebellar and sensory functional groups, agreement within 1 step occurred in at least 92% of cases. These findings suggest that differences of a single step on these scales may not reflect an important functional change. We recommend that at least a 2-step change (1.0 point on the EDSS and 2 points on the FS) is needed to be confident of an important change in the degree of disability or response to treatment in this disease.

Cyclophosphamide↗
PubMed1989

The prevalence of primary Sjögren's syndrome in a multiple sclerosis population.

A central nervous system illness closely resembling multiple sclerosis has been described in patients with primary Sjögren's syndrome. From these reports, the estimated prevalence of this syndrome could be similar to that of multiple sclerosis in a high-frequency area. We evaluated 192 consecutive patients in our multiple sclerosis clinic to determine if such cases had gone unrecognized. We did not find any patients with clinical or serological evidence of primary Sjögren's syndrome. We conclude that it is rare for neurological manifestations of Sjögren's syndrome to mimic multiple sclerosis in our population.

Adult↗
PubMed1989

Long-term use of antecubital veins for plasma exchange. The Canadian Cooperative Multiple Sclerosis Study Group.

True or sham plasma exchange was done weekly for 20 weeks in patients in two of the randomization groups in a prospective, blind clinical trial of experimental treatments for multiple sclerosis. Because patients could be randomized to receive sham plasma exchange and placebo medications, it was decided when the trial was designed that the use of fistulae, arteriovenous shunts, venous cutdowns, or other aggressive forms of venous access would not be permitted for any patient. Accordingly, patients judged to have inadequate superficial antecubital veins were ineligible for the trial. To date, only 13 (4.4%) of 294 patients considered for entry into the trial have been rejected on these grounds. In only 4 of the 93 patients undergoing exchange was it necessary to discontinue plasma exchange because of inadequate venous access. In 79.3 percent of the 1207 exchanges done in these patients, there were no problems of any kind with venous access. In 5.4 percent of these 1207 exchanges, it was necessary to terminate the procedure prematurely because of difficulties with patients' veins. Thus, the great majority of patients free of serious systemic illness (other than chronic progressive multiple sclerosis) can undergo weekly plasma exchange for up to 20 weeks using superficial antecubital veins without the need to resort to more invasive methods of venous access.

Bloodletting↗
PubMed1989

A referendum on clinical trial research in multiple sclerosis: the opinion of the participants at the Jekyll Island workshop.

Sixty-two experienced multiple sclerosis (MS) investigators attending a research workshop were asked their opinions about clinical trial design, outcome measures, and treatment. Respondents favored repeated clinical observations of neurologic function (eg, Expanded Disability Status Scale or Ambulation Index) over the opinion of a blinded physician and changes on magnetic resonance imaging. There was agreement that stable MS should not be treated with immunosuppressives. Corticosteroids were rated the most effective treatment for recent disease activity. Total lymphoid irradiation and immunosuppressives were judged more potent for the long-term management of progressive disease. No treatment, however, received the support of more than 11% of the respondents for being of "considerable efficacy" in the long-term management of MS. Most favored a placebo-controlled design in future trials. In order to judge the acceptability of current trial design, participants were asked to act as patient surrogates and to indicate whether they would agree to participate in 4 randomized trials for which they would be eligible. The majority consented to participate in the 3 major trials currently under way, and most refused to enroll in the 1 trial that had never been initiated.

Clinical Trials as Topic↗
PubMed1988

Postnatal NMR changes in guinea pig central nervous system: potential relevance to experimental allergic encephalomyelitis.

The age of sensitization determines the clinical course of experimental allergic encephalomyelitis (EAE) in the guinea pig. Adult animals immunized with central nervous system (CNS) tissue develop acute, fulminant EAE, whereas a relapsing-remitting illness resembling multiple sclerosis occurs if sensitization occurs in the first 2 weeks of life. This study characterized the changes in the proton nuclear magnetic resonance (NMR) relaxometry and imaging of the CNS during the immediate postnatal period. T1 and T2 relaxation times in cerebral hemispheres and spinal cords of strain 13 guinea pigs were consistently prolonged at birth, progressively shortened in the first few weeks of life, and achieved adult levels by age 6 to 11 weeks. There were no age-dependent differences in T1 and T2 relaxation times and tissue specific gravity in either strain 13 or Hartley guinea pigs following immunization with complete Freund's adjuvant, an agent previously reported to disrupt the blood-brain barrier to IgG and albumin in strain 13 guinea pigs. The CNS of neonatal guinea pigs appeared well myelinated by light microscopy and there was no apparent difference in the extent of myelination between newborn and adult animals. Although it was possible to distinguish gray from white matter in the cervical spinal cord of newborn guinea pigs by magnetic resonance imaging (MRI) techniques, gray/white contrast was less satisfactory in the cerebral hemispheres until approximately 6 weeks of life when it was possible to differentiate gray matter, white matter, and cerebrospinal fluid. This study indicates that NMR relaxation times change during early postnatal life, at a time corresponding to the unexplained differences in susceptibility to an immune challenge. These developmental changes appear to be independent of the degree of CNS myelination.

Aging↗