The use of the CPAX tool in a South African intensive care unit: clinical outcomes and physiotherapists' perceptions

Abstract

Background: There is limited research available on the use of outcome measures in intensive care units (ICU) in a South African setting.The Chelsea Critical Care Physical Assessment tool (CPAx) is a measure of morbidity related to physical function and assesses respiratory function and functional abilities of critically ill patients. Objectives: The objectives of this study were to establish the effect of the use of the CPAx tool on ICU and hospital length of stay (LOS) in the care of critically ill patients; to establish the usefulness of the CPAx tool according to patient admission diagnosis; to determine if a relationship exists between CPAx scores and severity of illness or general morbidity during ICU admission; and to establish physiotherapists’ perceptions and views towards the use of the CPAx tool in their daily clinical practice in ICU. Design: The study consisted of two parts. Part one was a quasi-experimental design with a historical matched control group. Part two was a survey-based design. Methods: The study took place in a South African public sector hospital. Twenty six participants each were recruited into the experimental and control groups. Participants from the control group were matched with participants in the experimental group according to age, gender, diagnosis and acute physiology and chronic health evaluation (APACHE) II scores. CPAx scores and sequential organ failure assessment (SOFA) scores were calculated for participants in the experimental group on alternate weekdays during their ICU stay. Comparisons of ICU and hospital LOS between the study participants and historical control group were done using an independent t-test. Pearson’s correlation coefficient was used to determine if a relationship existed between CPAx scores, APACHE II scores or SOFA scores. A p-value ≤ 0.05 was deemed statistically significant. A questionnaire was developed and was completed by the research assistants who administered the CPAx tool to participants in the experimental group in order to determine their perceptions of the tool. Results: The mean age for the CPAx group was 37.88 (±13.37) years and for the control group was 37.81 (±12.21) years. The CPAx group consisted of 14 (53.8%) participants who underwent surgical procedures and 12 (46.2%) participants with traumatic orthopaedic injuries. The control group consisted of 14 (53.8%) participants who underwent surgical procedures and 12 (46.2%) participants with traumatic orthopaedic injuries. The mean initial SOFA score for the CPAx group was 2.42 (±1.79) and for the control group was 4.15 (±2.6). A p=0.03 indicates that there was a statistically significant difference between the two groups with regards to initial SOFA scores. The mean SOFA score at ICU discharge for the CPAx group was 1.80 (±0.42) and for the control group was 2.87 (±1.81). A p=0.05 indicates that there was a statistically significant difference between the two groups with regards to SOFA scores at ICU discharge. The mean initial CPAx score for the experimental group was 29.73 points (±14.81) and the mean CPAx score at ICU discharge was 36.15 (±8.33). The mean CPAx scores changed by 9.45 points between admission and discharge from ICU for participants who underwent surgical procedures and the mean CPAx scores changed by 3.9 points between admission and discharge from ICU for participants who sustained traumatic orthopaedic injuries. The mean ICU LOS for the CPAx group was 5.84 days (±7.43) and for the control group was 4.56 days (±5.25). The mean hospital LOS for the CPAx group was 17.43 (±16.68) days and for the control group was 19.31 days (±15.79); however, in both cases differences were not statistically significant. APACHE II scores had a very weak negative correlation with initial CPAx scores. APACHE II scores had a very weak positive correlation with CPAx scores at ICU discharge. There was a statistically significant difference between the two groups with regards to initial SOFA scores (p=0.05). Initial SOFA scores had a statistically significant moderate negative correlation with initial CPAx scores (r=-0.45, p=0.02). Initial SOFA scores had a weak negative correlation with CPAx scores at ICU discharge. Initial CPAx scores had a moderate positive correlation with SOFA scores at ICU discharge. CPAx scores at ICU discharge had a very strong statistically significant positive correlation with SOFA scores at ICU discharge (r=0.80, p=0.05).The CPAx tool proved to be more responsive in a surgical population than in a trauma population. Clinicians had positive perceptions of the CPAx tool in the management of critically ill patients. Discussion: Participants in the CPAx group were well matched with those in the historical control group with regards to age, gender, diagnoses and severity of illness. Those in the CPAx group had lower extent of organ dysfunction than those in the control group which might account for their shorter period of hospitalisation. Patients with a higher risk for mortality on admission into the ICU displayed lower functional abilities and, in turn, lower CPAx scores were measured. A greater change in CPAx scores was observed for participants recovering from surgical interventions compared to those recovering from traumatic orthopaedic injuries. Participants with low morbidity at the time of ICU admission seemed to have a greater ability to perform functional activities during their ICU stay. Limitations of the study included a small patient sample, a limited number of research assistants as well as lack of content validation of the questionnaire used. A multi-centre trial on the use of CPAx in ICU patient management could yield a wider perception of physiotherapists regarding the usefulness of the tool in daily clinical practice. Measuring the effect of the CPAx tool on participants’ length of mechanical ventilation could also be an interesting clinical outcome to consider. Conclusion: The data presented in this study show that the use of the CPAx tool does not have an influence on ICU and hospital LOS in a small sample of surgical and trauma participants. The tool appears to be more useful when used in the care of patients who are recovering from surgical procedures rather than those who sustained complex traumatic injuries. Physiotherapy clinicians that participated in the study supported the use of the CPAx tool in this single-centre trial and generally had positive perceptions towards the use of the tool.