The use of clinical decision analysis tools such as the Ottawa rules with Emergency Departments (ED’s) and Minor Injury Units (MIU’s) to determine the need for X ray has become common place (Lilford et al, 1998). The proposed project is to carry out a randomised controlled trial to ascertain if the need for X ray can be determined in the pre hospital environment by appropriately trained Paramedics using the same decision analysis tools.

Background

For many patients the ambulance service is the first point of contact with the National Health Service (NHS) following any injury. Traditionally this would have resulted in their transportation to and treatment in the local Emergency department (Department of Health, 2004). The automatic transportation of patients to hospital for primary care began to be reviewed following the recommendations in the NHS plan (Department of Health, 2000) that greater use could be made of non medical staff to assess and treat patients.

In 2004 the then Minister for Health Mrs. R. Winterton stated that a patient who dials 999 with a non life threatening injury would no longer automatically be sent an ambulance but could be treated at home (Department of Health, 2004). This idea was developed further in 2005 in the Taking Healthcare to the Patient report (Department of Health, 2005a). Together these reports led to the development of Paramedics with additional clinical training and eventually to the role of Emergency Care Practitioners (ECP’s). ECP’s are trained in the use of the same decision analysis tools that would be used in ED’s such as the Ottawa ankle rules.

If this was extrapolated further, with a little extra training Paramedics with their current level of history taking and patient examination skills; could use the rules to screen adult patients with ankle injuries pre hospitally and potentially reduce ED attendances for this type of injury. This would provide patients with the most appropriate care and help compliance with the current political drivers to reduce attendances at ED’s (NHS Scotland, 2009).

Literature Review

The Ottawa ankle rule (Steil et al., 1992) was originally developed from retrospective study of 750 patients which was later tested and validated in a multi-centre controlled clinical trial of over 12,000 patients (Steill et al 1995). Injuries to the ankle and mid foot are commonly seen in ED’s (Bachmann et al, 2003). There are a number of studies that have looked the prevalence of ankle injuries. Watts and Armstrong (2001) note that ankle sprains account for between 3% and 5% of all emergency department attendances. Bridgeman et al. (2003) found that there are 50-60 ankle sprains in any population of about 10,000. It has been suggested that patients be encouraged to apply the rules to themselves (Blackham et al, 2008) but little agreement was found between patients and clinicians with the result that it was thought that demand for X rays might even increase.

Bachmann (2003) who carried out a systematic review of 27 studies involving 15,581 patients found the rules to be accurate as only 15% of these patients had fractures. This suggests if fully implemented the rules could reduce the number of unnecessary X rays by between 30 and 40%. Bachmann (2003) concluded a 97.8% sensitivity in a pooled result for both ankle and foot rules. The 2 % of missed fractures are reportedly almost certain to be small avulsion fractures that can safely be treated in the same way as an ankle sprain (Mayer, 2009).

There have been a number of other validation studies reviewing the accuracy of the ankle rules since their introduction, looking at their use by both medical and nursing staff. In a prospective observational study of 324 patients Salt and Clancy (1997) analysed the use of the rules by nurses, investigating which patients not sent for X ray by the nurses were subsequently found to have a fracture when reviewed by a doctor. The study showed that the nurses applied the rules safely as none of the 67 patients who did not receive an X ray found it necessary to reattend. In a retrospective study of 800 patients Perry et al (1999) concluded the rules had a sensitivity of 93.6% which they considered made them a useful aid to diagnosis but noted that they should be used with care. This is lower than the sensitivity in Steil et al (1995) and its outcome could lead to the use of the rules being viewed by some as unacceptable due to a 6% error factor. A more positive view of the rules for screening ankle injuries was concluded by Mann et al. (1998) whose results were similar to those reported by Steill et al (1995).

The rules have received some criticisms. Warren and Knottenbelt (2001) discuss the rule in a small (non-systematic) literature review, discussion and case study, and criticise the rules as their use may result in fractures of the talus and cuboid being missed. In one of the earliest studies Kelly et al (1994) conducted a multi-centre trial of 350 patients; 75 of these had fractures, and 5 would have been missed under the rule. This represented sensitivity of 93% with a false negative level of 14% was considered unacceptable by the authors; however this sample size is small in comparison to those carried out by both Steill (1995) and Bachmann (2003)

The literature review has disclosed no study’s into the pre hospital use of the rules by Paramedics and while it may be considered little more than a replication of some aspects of previous studies this study will be able to validate the use of the rules in a pre hospital setting by staff with no specific minor injury training.

Research methodology

The proposed research study hypothesises that Paramedics given suitable training can make safe and accurate decisions on which adult patients requesting ambulance attendance for an ankle injury require transportation to a place of secondary care for radiography.

The hypothesis for this study is based on two variables, that Paramedics either can or can’t correctly implement the Ottawa ankle rules. This matches Kerlingers (1986) definition of a hypothesis being ‘a conjectural statement of the relations between two or more variables’ and that of Polit and Beck (2004) in that it is a ‘statement of the researcher’s expectations about the relationship between the variables under investigation’. It also complies with Lewith and Little (2007) in that its question is explicit, focused and feasible.

As the study will be considering an alternative method of care for patients as opposed to the current standard treatment it will be carried out using a randomised control trial (RCT). RCT’s have proved to be an accurate way of providing robust answers when needed to evaluate a form of care and are stated to be ‘superior to any other method for producing evidence about the effectiveness of health and social care interventions’. (Shepperd et al., 1997). This can however be due to the results not being able to be achieved by any other method (Frank & Frank, 1991). As RCT’s involve the use of numbers in the collection of data this would therefore be a quantitative study with a positivist paradigm (Parahoo, 2006).

Research methods

While there has been some research into the use of the Ottawa ankle rules with paediatric patients with positive results (Clarke & Tanner, 2003). This study will only involve a population of adult patients as this is the population for which they were originally proposed (Stiell et al, 1992 & 1995). The population for inclusion in the trial will be drawn from adult patients for whom an ambulance has been requested and who are determined by the Advanced Medical Priority Dispatch System (AMPDS) (Clawson et al, 2009) to have an appropriate ankle injury.

Participants in the study will be allocated to the intervention or control groups by random assignment. This is recommended by Schulz (2001) as the only method of ensuring groups are equal and to eliminate bias. This method is also supported by Kendal (2003) who states that allocation by random assignment minimises the effect of any variables at the time of allocation. As participants’ allocation to their group will be effected by the time of their emergency call balancing the randomisation may be difficult to achieve (Parahoo, 2006). The groups will therefore be monitored for any variances in age and gender that could affect the results of the trial to ensure maximum validity.

On consenting to participate in the trial the patient will be allocated to either the intervention or control group by single patient randomisation using a telephone randomisation service. This would involve the Paramedics taking part in the trial contacting the service at the time the patient presents with an appropriate injury for inclusion. While this adds an extra element to the trial it will improve the chances of randomisation being achieved.

Cluster randomisation could be an alternative to this system; dividing participants into the groups based on the date of their call e.g. allocation to the control group on the even weeks of the trial and the intervention group on the odd weeks. While this would also produce reasonably randomised groups the proposed complete randomisation of allocation will provide a greater level of safeguard against bias (Bowling, 2002).

The characteristics of this study prevent the possibility of the blinding of either the patient’s or staff involved and therefore it is potentially open to bias. The blinding of the participants in an RCT would normally be considered essential to ensure the accuracy of its results (Kendal, 2003). Many patients call ambulances or attend the ED with the expectation of receiving an X ray and when it is determined that one isn’t necessary leave feeling a full examination has not been carried out regardless of how much explanation or education is given (Bessen et al, 2009). Some of the participating patients may therefore perceive they have been disadvantaged if they subsequently do not receive an X ray due to their involvement and may attend the ED under their own transport biasing the results. This will need to be taken into account when the results are interpreted. Normally the attrition of participants would also need to be considered when calculating the outcomes of the trial (Bottomly , 1997), however their minimal time involvement in this study will reduce this to an absolute minimum.

A retrospective analysis will be carried out to determine the number of eligible patients as determined by their AMPDS coding that have been attended by the Ambulance Service during the trial period. The call database will also be compared against the AMPDS system in the ambulance control to ensure that no potential participants have been overlooked.

The patients in the intervention group will be attended by one of the cadre of Paramedics trained in the implementation of the Ottawa ankle rules who will use them to determine if the patient requires transportation to the ED for radiology or if they can safely be treated at home. Patients within the control group will receive the current standard treatment of splintage and analgesia and transportation to the ED (Fisher et al, 2006).

The participants from both groups will be monitored for 14 days for a second call to the Ambulance Service or subsequent self representation at the ED for review of the same injury. This and a comparison of the numbers of the control group who received radiography against those referred by Paramedics will allow the safety of the rules implementation by Paramedics to be measured against that of the ED clinicians.

The larger the number of participants in the sample size the greater level of accuracy of the results but also the higher the costs of running the study; the sample size will therefore be determined by a feasibility study as suggested by Lewith and Little (2007). The exact sample size required for a given level of precision in the results can be estimated using a power calculation (Kendall, 2003). This allied with retrospective data from AMPDS will allow the duration of the study to be planned.

Agreement and support for the trial would be sought from the managers of all the Trusts involved; and Ethical approval will be gained from the Ethics committees of the Ambulance Service and the participating hospitals before the commencement of the study in line with the Research Governance Framework for Health and Social care (DOH, 2005b).

Thompson et al (2006), states that the fundamental ethical principles to be considered during research are Respect for persons, Justice and Beneficence. Respect for persons covers the researchers duty to safeguard the participants autonomy and dignity by ensuring informed consent and confidentially. To preserve confidentially all patient documentation will be anonymous, identified only by its Ambulance Service incident number. All participants will have the objectives of the trial explained to them by the attending Paramedic using a set text to ensure uniformity in the consent process and ensure that their consent is fully informed. This will also include details of how to withdraw from the trial. They will also be given a written copy of the trials objectives to review if they have any later questions before being asked to sign a consent form.

The principle of justice places a duty on researchers to ensure there is no variation in standards of care offered to different participants during the trial either as groups or individuals. It also places an emphasis on those carrying out the research that the benefits of the research are not made at the expense of the individual, who should be treated as the end and not just as a means to an end (Thompson et al, 2006).

The use of the Ottawa ankle rules has previously been well validated for screening patients in hospitals (Bachmann, 2003). This coupled with specific advice to be given to patients in the intervention group who after assessment are ultimately not transported to the ED; regarding the actions to be taken in the event of their condition worsening, or failing to resolve will ensure the duty of beneficence (non-malfeasance) or the avoidance of doing harm will be safeguarded.

Data Collection and Analysis

The accuracy of the rules implementation by paramedics will be determined by comparison of the re attendance figures and/or repeat 999 calls of the control group and the participants in the intervention group transported to the ED against those of the intervention group not transported for radiology. Comparison of these figures against the re attendance figures of the patients in both groups who did receive an radiology will give the findings further validity as the symptoms of any missed fractures will in all likelihood cause the patient to seek further medical aid. If the rules are being correctly applied all of the patients transported to the ED from the intervention group should receive an X ray.

The data collection will be from the pre existing patient record completed by either the Paramedic or ED clinician and by use of a questionnaire covering the findings on all of the pertinent aspects of an ankle examination using the Ottawa ankle rules. This will allow data collection to be structured and standardised as recommended by Parahoo (2006).

There will be five areas of data analysis, Firstly, the proportion of patients from both the control and intervention groups receiving radiography who were subsequently found not to have a fracture. Secondly, the proportion of patients from the intervention group taken to the Ed who subsequently did not receive an X ray. Thirdly, the proportion of patients in the intervention group not initially taken to the ED after examination who subsequently attended the ED or recalled 999 within 14 days for the same injury. Fourthly, the proportion of patients in the control group not initially given radiography who subsequently re attended or called 999 within 14 days for the same injury. Lastly the proportion of patients from the intervention group who were taken to the ED but were not given radiography and subsequently re attended or recalled 999 within 14 days for the same injury.

The results will be presented in a tabular format to allow for comparison. This allows researchers to demonstrate the relationships between the variables and to use inferential statistics to generalise these relationships to others (Parahoo, 2006). To generalise the trials results for relevance to other areas they must be shown to have internal and external validity (Parahoo, 2006). Internal validity will be shown from the conclusions drawn after the data is analysed. External validity demonstrates that the findings can be applied in other settings to similar populations.

‘P’ values will be associated with all of the results being compared to indicate the probability of chance. ‘P’ values should always be less than 5%. The relationship between the variables will be tested for independence using an appropriate test such as chi-square (Nieswiadomy, 2008) and the confidence interval computed for each result to estimate what the results would be in a perceived normal population as opposed to the sample population (Argyrous, 2007).

Timeline and budget

Initial timeline estimates suggest a 3 month trial but this would be confirmed by the pilot study and amended if the results of the pilot suggested it were necessary.

The participating Paramedics would be trained during in service training days thereby incurring no additional training costs. Data analysis would be carried out by the researchers using a statistical software package. While some packages can be downloaded for free; the price for a years licence for a purpose designed software package for a small numbers of researchers (<5), could be as much as £1500 dependant on the specific software purchased. Making this the largest financial outlay.

Conclusion

The Ottawa ankle rules like all decision analysis tools are useful in assisting with the decision making process but they can only be used in conjunction with a thorough examination and history taking. It needs to be recognised that like all decision analysis tools they are not infallible; for every 1000 patients that exhibit negative findings on examination using the Ottawa ankle rules 14 will actually have fractures (Mayer, 2009). They have however been being used successfully in ED’s since their conception.

It is anticipated that this RCT will produce valid results; its key limitations are the inability to blind the trial due to the nature of the intervention being researched and a lack of external validation of the results for use with paediatric patients.

If successful this research could benefit both the individual as well as the health care economy by allowing the patient to be assessed and treated in their own homes without necessitating their transport to the ED easing the workload of the ED and freeing an ambulance to potentially attend a more serious case.