Cath Lab Digest

In the second prospective controlled study, Strauss et al²² examined the cost-effectiveness of air-fluidized beds over a 36-week period and found that patients who received air-fluidized therapy required 55% fewer days in the hospital, with a shorter average period of hospitalization, as compared to the control group. Support surfaces used for the control group, chosen at the discretion of the treating physician, included alternating pressure pads, air support mattresses, water mattresses, and foam pads. The smaller sample size, selected to assess cost-effectiveness, was not sufficiently powered to demonstrate the efficacy of air-fluidized therapy to promote healing. Although controlled studies^23,24 demonstrate the efficacy of air-fluidized therapy as compared to conventional therapy to treat pressure ulcers, these studies did not specifically compare air-fluidized therapy to Group 1 and Group 2 support surfaces.

Additionally, studies with historical controls^25,26 and retrospective^27,28 and uncontrolled²⁹ studies have shown advantages of treatment with air-fluidized therapy as compared to conventional support surfaces. Although these study designs have distinct limitations, including the lack of randomization and the inability to control for multiple treatments that affect healing, they also offer advantages. For example, the importance of chart review data is discussed in a report of a large retrospective study by Berlowitz et al.⁴² The group reported results from Patient Assessment Files from 19,981 patients at a Veterans Administration hospital using a model developed to calculate expected pressure ulcer healing rates from chart data. Berlowitz et al stressed the high cost of prospective trials and highlighted the importance of retrospective analyses to identify effective treatment interventions. Thus, a retrospective chart review, as used in this study, provides a cost-effective opportunity to examine treatments in a typical community setting while incorporating larger numbers of patients than would be practical in a randomized controlled trial.

Comprehensive (or Computerized) Severity of Illness (CSI®). Severity scores, used to quantify hospitalized patients’ burden of illness, have been utilized for more than 25 years to assess mortality, length of hospital stay, and hospitalization costs.⁴³ Although no gold standard exists among severity indexes, the Comprehensive Severity Index (CSI®) also known as the Computerized Severity Index, developed in 1982, provides a valid and reliable measure of illness severity.⁴⁴ In a 1991 study evaluating six illness severity instruments, the CSI® compared favorably with the other systems, particularly in the area clinical acceptance by physicians.⁴⁵

The CSI® has been validated and used in a variety of clinical settings, including determining illness severity and resource use differences among Caucasian and African American hospitalized patients,⁴⁶ assessing illness severity in children hospitalized with bronchiolitis,⁴⁷ evaluating quality of care,⁴⁸ determining the relationship between hospital costs and the illness severity,⁴⁹ and assessing quality of care in patients with cardiac conditions.⁵⁰ The CSI® also has been modified to include separate components to measure severity of illness in ambulatory, long-term care, hospice, and rehabilitation settings.