MEASUREMENTS OF INTERFACE PRESSURE BETWEEN BODY SITES AND THE SURFACES OF FOUR SPECIALISED AIR MATTRESSES

SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites.     

Using serial observations to identify predictors of progression to AIDS in the Toronto Sexual Contact Study.

The Toronto Sexual Contact Study comprises a cohort of 249 male sexual contacts of men with HIV disease which has been followed every 3 months for almost 5 years. On enrollment 143 were seropositive and 16 seroconverted during the follow-up period. By 31 December 1989, 41 of the 159 seropositive cohort members had developed AIDS. Using Cox relative risk regression models, we investigated the association of a number of laboratory and clinical variables and progression to AIDS. Fixed covariate models examined laboratory variables from the enrollment visit of cohort members, with time calculated from this date. In models assessing time dependent covariates, time was calculated from the estimated date of HIV infection. In the univariate models of either fixed or time dependent covariates, many variables were significantly associated with risk of progression to AIDS (T4 cell count, T4/T8 ratio, blastogenic responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen, serum IgA, appearance of p24 antigen, and the development of oral hairy leukoplakia, thrush, or herpes zoster). Appearance of persistent generalized lymphadenopathy was not associated with increased risk of progression. In the multivariate model which evaluated fixed laboratory covariates, T4/T8 ratio, IgA level, and PHA response at enrollment were significantly associated with elevated risk.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interactions Between Cytomegalovirus, Human Herpesvirus-6, and the Recurrence of Hepatitis C After Liver Transplantation

Recurrence of hepatitis C (HCV) following liver transplantation is common. Herpesvirus reactivation following transplant may have an immunomodulatory effect resulting in increased HCV replication. We studied whether cytomegalovirus (CMV) and human herpesvirus-6 (HHV-6) may be associated with HCV recurrence and viral load after transplant. We prospectively followed 66 HCV liver-transplant recipients with serial viral load testing for CMV and HHV-6. Infection and viral load were correlated with the development of biopsy-proven HCV recurrence and HCV viral loads. Histologic recurrence of HCV occurred in 41/66 (62.1%) patients. In the primary analysis, CMV infection and disease, and HHV-6 infection were not associated with HCV recurrence. Peak CMV and HHV-6 viral loads were not significantly different in patients with and without recurrence. No correlation was observed between HCV viral loads at 1 and 3 months post-transplant and peak HHV-6 or CMV viral loads. In a subgroup analysis, HHV-6 infection was associated with the development of more severe recurrence (hepatitis and/or fibrosis score > or = 2) (p = 0.01). Also, fibrosis scores at last follow up were higher in patients with CMV disease (1.67 vs. 0.56; p = 0.016) and in patients with HHV-6 infection (1.18 vs. 0.55; p = 0.031). In conclusion, HHV-6 and CMV infection and viral load were not associated with increased overall rates of HCV recurrence or HCV viral load after liver transplantation but may be associated with more severe forms of recurrence.     

Early diagnosis of SARS: lessons from the Toronto SARS outbreak

The clinical presentation of SARS is nonspecific and diagnostic tests do not provide accurate results early in the disease course. Initial diagnosis remains reliant on clinical assessment. To identify features of the clinical assessment that are useful in SARS diagnosis, the exposure status and the prevalence and timing of symptoms, signs, laboratory and radiographic findings were determined for all adult patients admitted with suspected SARS during the Toronto SARS outbreak. Findings were compared between patients with laboratory-confirmed SARS and those in whom SARS was excluded by laboratory or public health investigation. Of 364 cases, 273 (75%) had confirmed SARS, 30 (8%) were excluded, and 61 (17%) remained indeterminate. Among confirmed cases, exposure occurred in the healthcare environment (80%) or in the households of affected patients (17%); community or travel-related cases were rare (<3%). Fever occurred in 97% of patients by the time of admission. Respiratory findings including cough, dyspnea and pulmonary infiltrates evolved later and were present in only 59, 37 and 68% of patients, respectively, at admission. Direct exposure, fever on the first day of illness, and elevated temperature, pulmonary infiltrates, lymphopenia and thrombocytopenia at admission were associated with confirmed cases. Rhinorrhea, sore throat, and an elevated neutrophil count at admission were associated with excluded cases. In the absence of fever or significant exposure, SARS is unlikely. Other clinical, laboratory and radiographic findings further raise or lower the likelihood of SARS and provide a rational basis for estimating the likelihood of SARS and directing initial management.     

Radiology and the Health Policy Agenda for the American People

Eleven radiologists appointed by the major radiological societies participated for the past 5 years in the development of the Health Policy Agenda for the American People. The Agenda is an action plan to address a wide variety of serious problems in medicine. The first phase involved establishment of 159 principles, broad value statements that were the foundation of the project. Phase 2 involved the development of policy proposals on 38 urgent issues for action in medical science; education; health resources; delivery mechanisms; evaluation, assessment, and control; and payment for services. These proposals are summarized in this report. The activities and recommendations of representatives for the field of radiology are described. The Agenda has been released, and an implementation phase has begun. It will likely be of great importance to the practice of radiology over the next decade. Important issues can be addressed by acting with the coalitions that are being formed from among the more than 150 participating organizations.