The following ssion of this assignment attempts to critically appraise the venUS III randomised control trial (RTC) published in the British Medical Journal. As a student/healthcare worker who is new to critical appraisal I am aware that I do not fully understand some of the calculations involved in reporting of findings, however Greenhalgh (2006) argued, ‘all you really need to know is what the best test is to apply in given circumstances, what it does and what might affect its validity/appropriateness’.
When caring for patients it is essential that Healthcare Professionals are using current best practice. To determine what this is they must be able to read research, as not all research is of the same quality or standard therefore Healthcare Professionals should not simply take research at face value simply because it has been published (Cullum and Droogan, 1999; Rolit and Beck, 2006). I am completing this assignment to cultivate the skills at enable me to effectively assess the validity of research that may shape my practice.
There are numerous tools available to help reviewers to critique research studies (Tanner 2003). I have elected to use the Critical Appraisal Skills Programme (CASP) tool. I chose CASP as it is simple, directive and appropriate to quantitative research. The research article had a clear concise and easily understandable title and abstract. Titles should be 10/15 words long and should clearly identify for the reader the purpose of the study (Connell Meehan, 1999). Titles that are too long or too short can be confusing or misleading (Parahoo, 2006).
From the abstract the reader should be able to determine if the study is of interest and whether or not to continue reading (Parahoo, 2006). The author(s’) qualifications and job can be a useful indicator into the researcher(s’) knowledge of the area under investigation and ability to ask the appropriate questions (Conkin Dale, 2005). The authors of the venUS III trial were from a range of academic and clinical backgrounds and are considered experts in their fields.
The VenUS III RTC clearly set out its objective to consider the clinical effectiveness of weekly high frequency ultrasound on hard to heal venous leg ulcers, (hard to heal was defined). In cases where participants had more than one venous leg ulcer the largest ulcer would be tracked if ultrasound treatment was allocated this site received the treatment. Outcomes to be considered where clearly outlined and method of measurement/collection defined. The study screened 1488 people with leg ulcers and 337 people became participants (22. %) Participants were randomised and evenly distributed, 168 to ultrasound therapy (dependant variable) plus standard care (experimental group) and 169 to standard care only (control group) This is reported as being the largest trial undertaken on the subject of therapeutic ultrasound for wound healing and earlier studies are referenced in support this statement. The study was cross-sectional, its population was taken from both community and district nurse led services as well as hospital outpatient clinics.
The 12 care settings used where taken from both rural and urban settings. A “good” sample is one that is representative of the population from which it was selected (Gay 1996) Venous leg ulcers rates rise sharply with age with an estimated 1 in 50 people over the age of 80 developing venous leg ulcers (NHS choices 2012). The age of the participants in the study ranged from 20-98 years old, however the median age overall was 71. 85 and the mean age was 69. 44 years old across the study, well below the age range where venous leg ulcers are most seen.
The assignment of participant’s treatment was equally randomised: treatment was blindly allocated: 168 to ultrasound therapy plus standard care and 169 to standard care only. Randomisation was conducted by an independent agency (York trials Unit) The lack of attrition bias was a strong positive for the venUS III trial, it had a low loss to follow up rate. The nurses providing treatment where not blind to which treatment had been allocated, this may impact on construct validity as in some cases it is suggested that control subjects are compensated in some way by healthcare staff or family for not receiving research intervention (Barker 2010).
Nurses who were blinded were employed to trace the ulcers. Participating patients were not blind to the treatment/s. As one of the measured outcomes was patients perceptions of health, assessed by a questionnaire (SF-12) it is reasonable to conceive that this assessment may have been influenced by the patients awareness of the treatment type they were receiving thus creating the possibility for assessment bias. Construct validity may also be impacted on peoples behaviours as a response to being observed or to the treatment because they believe it will have a positive effect. Barker 2010) Healing date was assessed remotely by independent assessors who where blind to the treatment allocation this guards against assessment bias. Overall both treatment groups were equal in size. Both treatment groups had an almost equal average age of study participants, this is important because inequality in age between the groups would represent a heterogeneous population (Barker 2010). Venous leg ulceration is more common in woman than men in those below 85 year of age (Moffat 2004) the trial participants had a female majority.
Probably the weakest element of the study was the probability of performance bias. Standard care comprised of low adherent dressings and four-layer bandaging that was high compression, reduced compression or no compression depending upon the participant’s tolerance. Any changes to the regime where recorded and where made at the discretion of the treating clinician. Standard care was practiced in accordance with local protocol and could have varied between locations the quality of standard care given may be considered to be a confounding variable.
Surveys of reported practice of leg ulcer care by nurses have demonstrated that knowledge often falls far short of that which is ideal (Bell 1994, Moffat 2004, Roe 1994) and that there is a wide variation in the nursing management of people with leg ulcers in the United Kingdom (UK) (Elliot 1996, Moffat 2004, Roe 1994). Large variation in healing rates according to trial centre is a further indicator that standard care is so variable that it potentially affects the reliability of results.
No treatment fidelity checks were undertaken and no observation regime beyond usual practice of the treating nurse’s practice was implemented despite nurses being new to ultrasound application. Nurses were deemed competent after one day of training, these nurses where then also considered competent to train other local nurses who would be providing treatment. The ultrasound treatment given during the venous III trial did not give any additional effect on ulcer healing or reoccurrence rate and it did not affect quality of life.
As the study only looked at one ultra sound regime extrapolation of the results was not possible, a between-subjects designed study may have provided data that was of further function. Treatment effect was measured precisely; the primary outcome measured was the time that the venous leg ulcer took to heal, this was measured in days and adjustments were made in order to account for baseline ulcer area (larger ulcer would be expected to take longer to heal than smaller ulcers).
A fully healed ulcer was clearly defined and the ulcers were photographed every four weeks, at the point of healing and seven days after full healing has occurred, assessment of the ulcer was completed by two blind independent assessors and where required a third assessor was used if outcome was inconclusive. In some cases no photographs were available for patients in this case the treating nurse assessed healing date, no explanation why photographs would not be available is given. 7. 8% of the sample were assessed by an unblinded nurse this presented some risk of assessment bias.
The trial also considered how many patients had fully healed ulcers within 12 months. Reduction in ulcer size was measured by area, by a blinded nurse who took acetate traces of the ulcers every four weeks the method of which was considered to be accurate and reliable and its provenance clearly referenced. Quality of life was also measured with a standardised questionnaire (SF-12) which looked at both physical and mental elements. As there is no evidence to support the use of ultrasound therapy in addition to standard treatment therefore no current change in practice is indicated and standard practice should continue.
The study reported significant heterogeneity in healing rates among the treatment centres. Centres that treated the most patients produced better healing overall, if there is a correlation between volume of patients treated and positive outcomes this hypothesis has the potential to impact upon the way care is delivered in the future. The trial considered not only medical outcomes but also considered changes in patient quality of life (both physical and mental). Beauchamp and Childress (2001) identify four fundamental moral principles: autonomy, non-maleficence, beneficence and justice.
Autonomy infers that an individual has the right to freely decide to participate in a research study without fear of coercion and with a full knowledge of what is being investigated. Participants gave written, informed consent and recruiting nurses were trained in consent procedures. Non- maleficence implies an intention of not harming and preventing harm occurring to participants both of a physical and psychological nature (Parahoo 2006). Patients who had a high probability of being harmed if they received the ultrasound where excluded from the trial, the exclusion criteria took into account contraindications.
Initially it was planned to exclude those unable to tolerate compression bandaging but after ethical consideration this was removed as these patients were identified as being particularly in need of the chance to benefit from ultrasound therapy. Beneficence is interpreted as the research benefiting the participant and society as a whole (Beauchamp and Childress, 2001). The annual cost to the NHS is estimated at ? 230-400 million (NHS Centre for Reviews and Dissemination, 1997; Bosanquet, 1992; Baker et al. 991) some individual health authorities are spending ? 0. 9m to ? 2. 1 million (Carr et al 1999). There are psychological implications to the patient in that the ulcer increases social isolation through limited mobility, uncontrolled exudate and odour, together with pain (Lindholm et al. 1993; Charles1995). Justice is concerned with all participants being treated as equals and no one group of individuals receiving preferential treatment (Parahoo, 2006). There is no evidence to suggest that any of the participants were discriminated against.
The following section attempts to discuss how evidence based health care enhances health care- looking at the evidence base within health care Evidence-based practice (EBP) is one of the most important developments in decades for the helping professions—including medicine, nursing, social work, psychology, public health, counselling, and all the other health and human service professions (Briggs & Rzepnicki, 2004; Brownson et al. , 2002; Dawes et al. , 1999; Dobson & Craig, 1998a, 1998b; Gilgun, 2005; Roberts & Yeager, 2004; Sackett et al. ,2000).
That is because evidence-based practice holds out the hope for practitioners that we can be at least as successful in helping our clients as the current available information on helping allows us to be. Evidence-based health care is the conscientious use of current best evidence in making decisions about the care of individual patients or the delivery of health services. Current best evidence is up-to-date information from relevant, valid research about the effects of different forms of health care, the potential for harm from exposure to particular agents, the accuracy of diagnostic tests, and the predictive power of prognostic factors
Courtney from Study Moose
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