Ranura para el módulo de memoria externo

There is considerable emphasis in clinical practice on diagnosing dysphagia. Various health care professionals are able to identify problems related to dysphagia, either via urea and electrolyte results showing dehydration, or through oral intake charts. This study determined that its clinical focus would be that of aspiration, defined as entry of bolus material below the level of the vocal cords, rather than dysphagia. Aspiration requires a specific assessment and will not necessarily be observed through normal intervention with patients by nursing and health care professional assessments. In order to identify patients who may be at risk of aspiration post-stroke, swallow screening tools usually define a number of clinical determinants that indicate a pathological response to swallowing, and would therefore indicate that aspiration had occurred.

The clinical determinants, used within the BESST to detect aspiration, were based on available literature and were presented on the Information Sheet in a way that was

easy to interpret without prior SLT training. The BESST requires a simple observation of the clinical determinant to signify aspiration prior to being directed to the appropriate management option.

Where the clinical determinants of aspiration are explicit, most screening tools rely on the cough reflex (DePippo et al., 1994; Smithard et al., 1997; Daniels et al., 1998; Hinds and Wiles, 1998; Addington et al., 1999; Perry, 2001a,b; Massey and Jedlicka, 2002; Wu at al., 2004) but this relies on the preservation of pharyngeal sensitivity and an intact cough reflex (Mari et al., 1997). Most studies identify clusters of clinical determinants (Smithard et al., 1997; Daniels et al., 1998; Perry, 2001a,b; Massey and Jedlicka, 2002; Wu at al., 2004), which individually may vary in their sensitivity and specificity. Nevertheless, all of these studies include recognition of the cough reflex, which is recognised as a prime indicator of aspiration (Logemann et al., 1999; Addington et al., 1999). This effectively increases the sensitivity of the combined clinical determinants.

However, aspiration can occur silently, with the patient not demonstrating any patho- physiological response to aspiration. Absence of a cough reflex owing to diminished laryngeal sensitivity caused by the stroke would result in aspirated material going undetected. Evidence of silent aspiration has been reported in the literature, with different levels of prevalence: 22% of patients (Daniels et al. 1997), 39% of patients (Holas et al. 1994) and 8% of patients (Kidd et al. 1993) when comparisons were made on VFES.

Exploring the face validity of the BESST suggested that the nurses would understand the clinical determinants described on the Information sheet. However, the interviews undertaken to establish face validity were only undertaken on a small sample size (six nurses and six SLTs). Despite assurances that the clinical determinants were explicit, further research may identify that they were incorrectly assigned to patients as

coughing during the procedure may be due to a plethora of other medical conditions.

The clinical determinants of aspiration in the SSA that the nurses used were „cough‟ and „wet gurgly voice‟. Neither nurse used „absent swallow‟ or „breathlessness‟. This could be interpreted to mean that these determinants are more difficult to detect because they are silent. However, when using the BESST, and when testing with water, the determinant „wet breath sounds‟ was frequently observed. Therefore, it might be that seeing the words „wet breath sounds‟ makes the nurses more vigilant and

when testing with thickened fluids, „wet breath sounds‟ and „cough‟ were still frequently reported.

„Weak movement of the larynx‟ was used as a determinant on only four occasions (two when testing with water). This determinant requires palpation of the hyo-laryngeal structures. Nurses are unfamiliar with this protocol and were not trained to palpate the larynx. This has implications for training if the diagnostic accuracy of the BESST is to be improved.

Analysis of the nurses‟ contemporaneous reasoning did not reveal specific reasons to justify their patterns of observation. A potential reason for the nurses being unable to accurately discriminate these determinants may be due to the confounding clinical features that present with stroke. Reduced levels of alertness, fatigue, reduced appetite and lack of insight may be present. These symptoms may obscure the clinical

determinants of aspiration, and result in nurses failing to identify patients at risk.

The contemporaneous reasoning data further demonstrates that clinicians and nurses prevaricate when required to determine the relative importance of various symptoms of aspiration in clinical practice. This means that even when clinical determinants are observed by all raters, some are disregarded as insignificant. In these instances the rater is using their knowledge and experience to determine what clinical determinants are relevant.

Some studies include an option of „other concerns‟ (Smithard et al., 1997; Perry, 2001a,b), allowing the person undertaking the study to apply their clinical experience. However, this renders the tools unreliable in clinical practice because the clinical reasoning, that is not reported, varies between individual health care professionals.

Therefore, the effects of training to observe and report clinical determinants of aspiration may result in a more diagnostically accurate tool. Further research that investigated the effectiveness of the training in swallow screening, offered to nurses and health care assistants, may prove to be useful in the identification of aspiration. Particularly because nurses and health care assistants are often the healthcare group that are commissioned with the task of feeding the patients who need assistance; this healthcare group are therefore most likely to notice ongoing and fluctuating aspiration signs.

9.4 Strengths

The BESST was designed with various foci: delivery of a screening tool in a timely fashion in order to maintain the integrity of lung tissue and function; and potentially improve the quality of care offered to stroke patients with dysphagia. The introduction of a swallow screening tool with a management option of modified oral intake is an extension of the water swallow screening tool (SSA) used in current clinical practice.

The SSA is based on the widely accepted 3 oz water swallow test screen (DePippo et al., 1992). However, the clinical utility of the SSA has been questioned (Suiter and Leder, 2008). It was suggested that 1,304/1,849 (71%) of patients were being

unnecessarily denied oral intake when the 3 oz water swallow test was compared with FEES® in a heterogeneous population (Suiter and Leder, 2008). Moreover, other research supports the idea that if a screening tool is used, which gives the option of a modified diet, then patients can be safely given a modified diet rather than be left nil by mouth (Trapl et al., 2007).

The BESST would have allowed a modified diet on 35/38 (92%) occasions where the SSA would have placed the patients nil by mouth, potentially unnecessarily. Therefore, the BESST offers the potential for an improved quality of care over the SSA because it agreed with the SLT, and allowed modified diet in the majority of cases. The three patients where the BESST would have potentially made an unsafe recommendation is discussed in detail on page 171.

Whilst the SSA does offer nurses the facility to identify clinical determinants of aspirated fluids, it offers limited management options which may incur a delay in the introduction of oral intake whilst awaiting further specialist assessment. The BESST offers the facility for nurses to modify oral intake immediately following the screen (Figure 8.1), without a delay.

Figure 9.1: Comparison of the BESST and SSA speed of appropriate management for oral intake

For patients who would ultimately be placed on thickened fluids and puree diet by the SLT undertaking the specialist assessment, the BESST, rather than the SSA, would be the preferred screening tool for the nurses performing the screen. The SSA would dictate that the patient should receive nil by mouth and possible naso-gastric tube feeding whilst awaiting the SLT assessment. However, the BESST would allow modified oral intake immediately following the screening tool, thereby considerably reducing the time taken to reach the appropriate management option, and improving the patient experience by preventing a nil by mouth scenario and obviating the need for a naso-gastric tube.

1. nil by mouth