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Biomedical subjects

I Mitchell

Publications and source records attributed to I Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed1997

Economic evaluation of respiratory syncytial virus infection in Canadian children: a Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) study.

OBJECTIVES: To quantify the cost and distribution of health care resources consumed annually in management of Canadian children from birth to 4 years of age with respiratory syncytial virus (RSV) infection. STUDY DESIGN: Estimates of direct medical expenditures (in 1993 U.S. dollars) were collected from a prospective cohort study of hospitalized children with RSV and from national and provincial databases. RESULTS: The annual cost of RSV-associated illness was almost $18 million. The largest component of direct expenditures (62%) was for inpatient care for the estimated 0.7% of all infected children ill enough to require admission. Physician fees comprised only 4% of inpatient expenses. Expenditures for ambulatory patients accounted for 38% of direct costs. CONCLUSIONS: The greatest reductions in the economic cost of RSV infections will be found in interventions that reduce duration of or prevent hospital stay. Costs for management of RSV infection in children in the Canadian health care system are considerably less than charges reported in the United States.

Absenteeism↗
PubMed1997

Positive correlation of algD transcription to lasB and lasA transcription by populations of Pseudomonas aeruginosa in the lungs of patients with cystic fibrosis.

Pseudomonas aeruginosa causes a chronic infection in the lungs of individuals with cystic fibrosis. The P. aeruginosa isolates from these infections, when grown under laboratory conditions, characteristically are mucoid and produce low levels of the more destructive virulence factors, such as exotoxin A and the proteases. We wanted to determine if during the chronic lung infections associated with CF, the expression of alginate was inversely correlated to the expression of exotoxin A, elastase, and the LasA protease. We measured the transcript accumulation of algD, a marker of alginate, toxA, the structural gene for exotoxin A, lasB, the structural gene for elastase, and lasA, the structural gene for LasA protease, from the sputum bacterial populations of 23 patients. In the 131 samples tested, we frequently detected transcripts from the four genes. When a Spearman rank correlation analysis was done on the samples, we found no correlation between algD transcript accumulation and toxA transcript accumulation. This result suggested that toxA was regulated independently of algD. Curiously, we found a positive correlation between algD transcript accumulation and both lasB and lasA transcript accumulation levels. This correlation may not indicate a direct association between algD and either lasA or lasB. More likely, it indicates a common regulatory element in a cascade of regulators or a common environmental cue that triggers transcription.

ADP Ribose Transferases↗
PubMed1997

Nosocomial respiratory syncytial virus infection in Canadian pediatric hospitals: a Pediatric Investigators Collaborative Network on Infections in Canada Study.

OBJECTIVE: To determine nosocomial transmission of respiratory syncytial virus (RSV) in Canadian pediatric hospitals, outcomes associated with nosocomial disease, and infection control practices. DESIGN: A prospective cohort study in the 1992 to 1994 winter respiratory seasons. SETTING: Nine Canadian pediatric university-affiliated hospitals. PARTICIPANTS: Hospitalized children with symptoms of lower respiratory tract infection (at least one of cough, wheezing, dyspnea, tachypnea, and apnea) and RSV antigen identified in a nasopharyngeal aspirate. RESULTS: Of 1516 children, 91 (6%) had nosocomial RSV (NRSV), defined as symptoms of lower respiratory tract infection and RSV antigen beginning >72 hours after admission. The nosocomial ratio (NRSV/[com-munity-acquired RSV {CARSV})] + NRSV) varied by site from 2.8% to 13%. The median length of stay attributable to RSV for community-acquired illness was 5 days, but 10 days for nosocomial illness. Four children with NRSV (4. 4%) died within 2 weeks of infection, compared with 6 (0.42%) with CARSV (relative risk = 10.4, 95% confidence interval: 3.0, 36.4). All sites isolated RSV-positive patients in single rooms or cohorted them. In a multivariate model, no particular isolation policy was associated with decreased nosocomial ratio, but gowning to enter the room was associated with increased risk of RSV transmission (incidence rate ratio 2.81; confidence interval: 1.65, 4.77). CONCLUSIONS: RSV transmission risk in Canadian pediatric hospitals is generally low. Although use of barrier methods varies, all sites cohort or isolate RSV-positive patients in single rooms. Children with risk factors for severe disease who acquire infection nosocomially have prolonged stays and excess mortality.

Canada↗
PubMed1997

Does ribavirin impact on the hospital course of children with respiratory syncytial virus (RSV) infection? An analysis using the pediatric investigators collaborative network on infections in Canada (PICNIC) RSV database.

OBJECTIVES: To determine the relationship between receipt of aerosolized ribavirin and the hospital course of high-risk infants and children with respiratory syncytial virus (RSV) lower respiratory infection (LRI). METHODS: The 1993-1994 Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) RSV database consists of prospectively enrolled children with acute RSV LRI, admitted to nine Canadian pediatric tertiary care centers. After excluding cases with compromised immunity and/or nosocomial infection, subsets with any congenital heart disease (CHD), chronic lung disease (CLD), age </=6 weeks (INFANT), gestation </=36 weeks (PREM), or severe disease within 48 hours of admission as shown by an oxygen saturation </=90% or an FiO2 requirement of >.35 (EARLY HYPOXIA) were studied in two ways. First, each risk group subset was analyzed separately to assess the association between ribavirin receipt and measures of disease severity including duration of intensive care, mechanical ventilation, hypoxia and RSV-attributable hospital stay. Secondly, ribavirin was added as an independent variable to a previously described multiple regression model for RSV-attributable length of hospital stay and two mutually exclusive subsets were analyzed: 1) previously healthy patients with >/=1 of: INFANT, PREM, or EARLY HYPOXIA; 2) patients with CHD and/or CLD. RESULTS: Between January 1993 and June 1994, 1425 community-acquired hospitalized cases of RSV LRI were entered into the RSV database. Among these 750 (52.6%) fit into one or more of the defined subsets including 97 CHD, 134 CLD, 213 INFANT, 211 PREM, and 463 EARLY HYPOXIA. The proportion ventilated in each group was 20.6%, 20.9%, 15.5%, 15.2%, and 13.3%, respectively. Across the subsets ribavirin use ranged from 36% to 57% of ventilated patients and 6% to 39% of nonventilated patients. For nonventilated patients in each subset the median RSV-attributable hospital length of stay (RSV-LOS) was 2 to 3 days longer for ribavirin recipients and the duration of hypoxia was significantly increased. Duration of intensive care unit (ICU) stay was also increased for all ribavirin-treated subgroups except those with CHD. In contrast, for ventilated patients, ribavirin therapy was not significantly associated with any of the outcome measures regardless of risk group. In the multiple regression model, ribavirin was significantly associated with a prolonged RSV-LOS both for children with CHD and/or CLD as well as for those whose only risk factors included INFANT, PREM, and/or EARLY HYPOXIA. CONCLUSIONS: These data raise further doubts about the clinical effectiveness of ribavirin in infants and children with risk factors for severe disease. Selection bias, with ribavirin used for sicker children, may have influenced outcome. Nevertheless the long durations of hospitalization, ICU, ventilation, and oxygen supplementation in nonventilated ribavirin recipients stress the need for further randomized trials to assess its efficacy.

Antiviral Agents↗
PubMed1997

PICNIC (Pediatric Investigators Collaborative Network on Infections in Canada) study of the role of age and respiratory syncytial virus neutralizing antibody on respiratory syncytial virus illness in patients with underlying heart or lung disease.

OBJECTIVE: To determine the effects of age and respiratory syncytial virus (RSV) antibody status on frequency and severity of RSV infections in children with underlying heart or lung disease. DESIGN: Cohort study conducted during two consecutive RSV seasons. SETTING: Ambulatory patients at eight Canadian pediatric tertiary care centers. METHODS: Subjects under 3 years old with underlying heart disease who were digoxin-dependent or had not received corrective cardiac surgery or with underlying lung disease were enrolled. Demographic information and an acute sera for RSV neutralizing antibody was obtained on enrollment. Weekly telephone follow-up consisting of a respiratory illness questionnaire was followed with a home visit to obtain a nasopharyngeal aspirate when there was new onset of respiratory symptoms. The specimen was used to detect RSV antigen. RSV illnesses were grouped as upper or lower respiratory tract infection (LRI) based on clinical and radiographic findings. RSV hospitalizations were considered to be those RSV infections that resulted in hospitalization. RESULTS: Of 427 enrolled subjects, 160 had underlying lung disease only, 253 had underlying heart disease only, and 14 had both. Eleven percent and 12% of lung and heart disease groups, respectively, had an RSV LRI. Three percent and 6% of lung and heart disease groups, respectively, were hospitalized with RSV infection. A significant decrease in frequency of RSV LRI and RSV hospitalization occurred with increasing age, with a major drop in those older than 1 year vs those younger than 1 year. Acute sera were available from 422 subjects. Geometric mean RSV antibody titers demonstrated a U-shaped distribution with increasing age. The trend to lower antibody concentrations in premature infants did not reach statistical significance. The frequency of RSV infection and RSV LRI was lower in patients with antibody at a titer more than 100, although the difference for RSV hospitalization was not statistically significant. These differences remained significant after age adjustment. CONCLUSION: Both age and RSV antibody status impact on RSV illness and LRI. Reduction in illness frequency with increasing age may lead to more informed targeting of those children most likely to benefit from RSV immune globulin prophylaxis.

Age Distribution↗
PubMed1996

Study of interobserver reliability in clinical assessment of RSV lower respiratory illness: a Pediatric Investigators Collaborative Network for Infections in Canada (PICNIC) study.

Randomized trials of ribavirin therapy have used clinical scores to assess illness severity. Little information on agreement for these findings between observers has been published. We decided to determine interobserver agreement for (1) a history for apnea or respiratory failure; (2) assessment of cyanosis, respiratory rate, retractions, and oximetry; and (3) determination of reason for hospitalization (requirement for medications, supportive care, underlying illness, poor home environment). At eight centers 137 RSV-infected patients were assessed by two observers blinded to the assessments by others with no interventions made between assessments. Observations were categorized, and agreement was summarized as percentage of observed agreement, Pearson correlation, or as a kappa statistic. Observed agreement for a history of either apnea or a respiratory arrest was at least 90% at all centers, with seven of the eight centers in total agreement. At all centers except one, the agreement on the reason why the patient remained in hospital was at least 80%. The observed agreement for assessing cyanosis was at least 94% at all eight centers. The correlation coefficient for respiratory rate varied from 0.42 to 0.97 across centers. The kappa values for agreement beyond chance for retractions varied from 0.05 to 1.00. The kappa values for oxygen saturation measures varied from 0.31 to 0.70. Although not statistically significant, there appeared to be more variation as the time between assessments increased. In conclusion, agreement for historical findings and assessment of cyanosis was high. However, there was wide variation in agreement in the other assessments. Training to ensure consistent and reproducible assessment by different examiners will be necessary if these findings are to be used as outcome variables in clinical trials.

Antiviral Agents↗
PubMed1996

Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) study of admission and management variation in patients hospitalized with respiratory syncytial viral lower respiratory tract infection.

OBJECTIVE: To describe differences in patients hospitalized with respiratory syncytial virus (RSV) lower respiratory tract infection (LRI) at nine Canadian tertiary care hospitals. In addition, this study describes the variation in use of drug and other interventions. METHODS: Data on patients hospitalized with RSV LRI and their outcomes were prospectively collected. Demographic data were obtained on enrollment by center study nurses. Data recorded daily included clinical assessment, oxygen saturation determination, and interventions (bronchodilators, steroids, ribavirin, antibiotics, intensive care, and mechanical ventilation) received during the day. Patients were divided into those with underlying diseases including congenital heart disease, chronic lung disease, immunodeficiency, or multiple congenital anomalies and those who were previously healthy. Mean RSV-associated length of stay and the proportion of patients receiving each intervention in each group were determined by hospital. RESULTS: A total of 1516 patients were enrolled at nine hospitals during January 1 to June 30, 1993, and January 1 to April 30, 1994. Significant differences were observed among hospitals in the proportion of patients with underlying disease, postnatal age less than 6 weeks, hypoxia, and pulmonary infiltrate on chest radiograph. The mean length of stay varied among hospitals from 8.6 to 11.8 days and 4.6 to 6.7 days in compromised and previously healthy patients, respectively. Except for receipt of bronchodilators, compromised patients were significantly more likely to receive interventions than previously healthy patients. There was variation among hospitals in receipt of most interventions in compromised and previously healthy patients. This variation was statistically significant for previously healthy patients but not statistically significant in those with underlying disease, because the numbers of patients in the latter group were much smaller. The magnitude of the variation for each intervention, however, was not different between those with underlying disease compared with previously healthy patients. CONCLUSION: Differences exist among tertiary pediatric hospitals in the nature of the patients admitted with RSV LRI. Variation occurred in the use of five interventions among the hospitals, regardless of whether the patient had underlying illness or was previously healthy. Given their current widespread use, high cost, and potential side effects, randomized clinical trials are needed to determine the efficacy of different drug treatments used to treat infants hospitalized with RSV.

Adrenal Cortex Hormones↗
PubMed1995

Anti-tuberculous therapy and acute liver failure.

The incidence of tuberculosis has been increasing since 1987, exposing a greater number of patients to the risks of three potentially hepatotoxic drugs, isoniazid, rifampicin, and pyrazinamide. Awareness of potentially severe drug hepatotoxic reactions is vital because fulminant hepatic failure is a devastating and often fatal condition without liver transplantation. We report four cases of fulminant hepatic failure caused by rifampicin, isoniazid, or both. These cases highlight the need for stricter adherence to and review of current guidelines on liver function tests after starting anti-tuberculous therapies.

Adult↗
PubMed1994

Cerebral lupus.

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Adolescent↗