JCPSLP Vol 22 No 2 2020

Learning from our clients

Low technology audit methods of pre-packaged thickened fluids using the Bostwick Consistometer, the Line Spread Test and the Flow Test A comparison of compliance Jane Ross, Maria Schwarz, Marnie Seabrook, and Anne Coccetti

It is critical for patient safety that patients with dysphagia are provided with thickened fluids at the appropriate level of thickness. The primary aim of this study was to use three commonly utilised low technology audit methods – the Bostwick Consistometer (the Bostwick), the Line Spread Test (LST) and the International Dysphagia Diet Standardisation Initiative (IDDSI) Flow Test (the Flow Test) – to conduct an audit of pre-packaged thickened fluids to determine compliance against norms. Based on this small pilot study, approximately 61% of samples were compliant using the Bostwick, 62% of the samples were compliant using the LST, and 87% samples were compliant using the Flow Test. There were reduced levels of agreement between the three audit methods – only on 37% of occasions was there complete agreement regarding compliances. Low levels of agreement suggest that further research would be beneficial to ensure auditing conducted with low technology tools is valid and reliable. D ysphagia is a common complication resulting from numerous medical conditions (Germain, Dufresne & Ramaswamy, 2006) and the impact of dysphagia on health and health outcomes can be substantial (Altman, Yu & Schaefer, 2010; Martino et al., 2005; Patel et al., 2017; Sura, Madhavan, Carnaby & Crary, 2012). The use of thickened fluids in the management of dysphagia is common (Garcia, Chambers & Molander, 2005; Steele et al., 2015) and the current Australian Standards (Dietetics Association of Australia & Speech Pathology Australia, 2007) propose three levels of thickened fluids that can be recommended to patients in Australia – mildly thick, moderately thick and extremely thick fluids. It is critical for patient safety that the recommended level of thickened fluids is provided to patients (Dietetics Association Australia & Speech Pathology Australia, 2007; Hadde, Cichero & Nicholson, 2016; Hadde, 2017) and regular auditing is therefore recommended. If a liquid is too thin, it may be

potentially aspirated resulting in pneumonia (Cichero et al., 2013; Miller & Watkin, 1996). Alternatively, if a liquid is too thick, a patient may be at increased risk of aspiration secondary to post-swallow pharyngeal residue (Hind et al., 2012; Newman, Vilardell, Clavé & Speyer, 2016). Available research points to the numerous challenges involved in auditing and measuring the viscosity of thickened fluids due to the complex rheological characteristics of thickened fluids (Cichero et al., 2017; Hadde, 2017; Hanson, 2016; O’Leary, Hanson & Smith, 2010; O’Leary, Hanson & Smith, 2015). First, there are a number of factors which influence the rheological characteristics of thickened fluids in addition to viscosity (Cichero et al., 2017; Hanson, 2016) including temperature, elasticity, propulsion pressure, the applicable shear rate and cohesion (Cho, Yoo & Yoo, 2015; Hadde, 2017; Cichero et al., 2017; O’Leary et al., 2015; Nishinari, Turcanu & Nakauma, 2019). Second, as thickened fluids are considered non-Newtonian with more complex flow properties dependent on the rate of deformation, they are unable to be completely characterised by one viscosity measurement (Cichero et al., 2017; Hadde, 2017; O’Leary et al., 2010) as would be provided by majority of low technology auditing methods. A rheometer or viscometer are the optimal “gold standard” devices to measure viscosity accurately (Adeleye & Rachal, 2007; Hadde, 2017). These devices are, generally used exclusively in research laboratories and are not routinely available in health care sites or in the community primarily due to their high cost (Garcia, Chambers & Cook; 2018). However, these devices are commonly used by manufacturers of pre-packaged thickened fluids to ensure compliance with prescribed standards. In the absence of access to a rheometer, several low technology devices are used by health care professionals to measure the viscosity of thickened fluids, including the Bostwick Consistometer (the Bostwick) (Germain, Dufresne & Ramaswamy, 2006; Steele et al., 2014), the Line Spread Test (the LST) (Mann & Wong, 1996), and the IDDSI Flow Test (the Flow Test) (Cichero et al., 2017). It has been reported that the Bostwick is relatively accessible, time efficient, cost effective and can provide useful clinical information (Germain, Dufresne & Ramaswamy, 2006). The LST has been found to grossly indicate whether thickened fluids can be categorised in the nectar thick or honey thick category (Budke, Garcia & Chambers, 2008; Garcia, Chambers & Cook, 2018; Nicosia & Robbins, 2007), which are grossly equivalent to the mildly thick level

KEYWORDS AUDIT DYSPHAGIA RHEOLOGY THICKENED FLUIDS VISCOSITY

THIS ARTICLE HAS BEEN PEER- REVIEWED

Jane Ross (top) and Maria Schwarz

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JCPSLP Volume 22, Number 2 2020

Journal of Clinical Practice in Speech-Language Pathology