Sensitivity and specificity of a nurse dysphagia screen in stroke patients.
To determine how well an institutionally developed nurse dysphagia screening tool correctly identified the presence (sensitivity) or absence (specificity) of dysphagia in patients following acute stroke.
A method-comparison design was used to compare results of the Nurse Dysphagia Screen to the dysphagia evaluation by a speech and language pathologist (SLP). Each newly diagnosed participant served as his or her control, with both dysphagia evaluations (nurse, SLP) occurring within 2 hours of each other. Sensitivity and specificity of the Nurse Dysphagia Screen was calculated using standard formulas.
For 49 patients evaluated following stroke, average age was 71.7 (SD [+ or -] 13.5). Twenty-five subjects were female and 24 were male. The majority of the participants had strokes identified as ischemic in origin (n=35). The SLP found 18 (37%) participants had a positive dysphagia assessment. The Nurse Dysphagia Screen was positive in 16 of 18 participants screened positive by SLP, resulting in some type of dietary restriction. The Nurse Dysphagia Screen was negative in 28 of the 31 patients screened as negative by SLP. Sensitivity and specificity of the Nurse Dysphagia Screen were 89% and 90%, respectively.
An easy-to-use, institutionally developed nurse dysphagia screening tool successfully identified patients with swallowing difficulties after stroke later diagnosed by SLP.
Following an acute stroke, approximately 20%-33% of patients initially have difficulty swallowing (Cichero, Heaton, & Bassett, 2009; Donovan et al., 2013). Presence of swallowing difficulties (dysphagia) dramatically increases the risk for aspiration pneumonia if patients are allowed to ingest food or fluids by mouth (Cichero et al., 2009).
Dysphagia is diagnosed by speech and language pathologists (SLPs) based on clinical examination and assessment of swallowing capability, with or without video fluoroscopy (Donovan et al., 2013). Because this definitive diagnosis by SLPs may not be available for 24-48 hours after patient admission, an initial screening for dysphagia is performed by nurses during the admission process. If the initial nurse screening for dysphagia determines the patient is at risk for aspiration, the patient is allowed nothing by mouth (NPO) until the SLP can complete a diagnostic evaluation.
Review of the Literature
Literature was reviewed by searching primary health care databases (CINAHL, PubMed) from 1980 to 2013. The search dates were based on a desire to include studies about early dysphagia screening tools that remain in use. Keywords used in the search included dysphagia screening, swallowing difficulties, assessment of swallowing difficulties, assessment of dysphagia, SLP dysphagia assessment, SLP swallowing assessment, bedside swallowing assessment, bedside dysphagia assessment, stroke guidelines, dysphagia evaluation, and swallowing evaluation.
While national experts and regulatory standards require patients hospitalized with an acute stroke to be assessed upon admission with some type of dysphagia screening tool, no specific tool is required or recommended (Daniels, Anderson, & Willson, 2012; Donovan et al., 2013; Schepp, Tirschwell, Miller, & Longstreth, 2012). A variety of bedside screening tools for dysphagia have been developed, with each tool having different evaluation criteria (Antonios et al., 2010; Bravata et al., 2008; Daniels, McAdam, Brailey, & Foundas, 1997; DePippo, Holas, & Reding, 1992, 1994; Edmiaston, Connor, Loehr, & Nassief, 2010; Gottlieb, Kipnis, Sister, Vardi, & Brill, 1996; Martino et al., 2009; Massey & Jedlicka, 2001; Perry, 2001a, 2001b; Smithard et al., 1998; Trapl et al., 2007; Turner-Lawrence, Peebles, Price, Singh, & Asimos, 2009). All include a preliminary assessment of clinical characteristics commonly associated with difficulty swallowing, such as decreased alertness, drooling, wet voice or breath sounds, or hoarse voice quality. Also frequently included is some type of swallowing test using a specified amount of water (5 ml-100 ml) to assess coughing, shortness of breath, and/or changes in voice quality immediately after swallowing. Some dysphagia screens also include assessment of the gag reflexive response, and tongue and facial movements, and/or a swallowing test with semi-liquid or soft foods.
Many prior studies have determined the sensitivity (ability of a screening tool to correctly identify the presence of dysphagia) and specificity (ability of a screening tool to correctly identify absence of dysphagia) of nursing dysphagia screening tools. No screening tool has been found to have excellent sensitivity and specificity in more than one study, with most tools having sensitivity of greater than 70%, with specificity of 52%-69% (Daniels et al., 2012; Donovan et al., 2013; Schepp et al., 2012; Westergren, 2006). Consequently, no national recommendation exists concerning use of a specific dysphagia screening tool with patients who have experienced stroke.
In 2008, a task force of nurses and SLPs at a 421-bed community-based acute care facility in the southeastern United States reviewed available evidence on dysphagia screening tools and revised the institution's existing dysphagia screening tool used by nurses to evaluate patients admitted after acute stroke (see Table 1). The final screening tool combined components from multiple tools because no one published screening tool seemed to address all clinical items considered essential by task force members. Because the final screening tool reflected a combination of different components from several existing tools, actual sensitivity and specificity of the final dysphagia screening tool were not known. The purpose of this study was to determine how well the institution's Nurse Dysphagia Screen correctly identified the presence (sensitivity) or absence (specificity) of dysphagia in patients following acute stroke.
This study was conducted on a 20-bed medical neurology unit and 9-bed neurology intermediate care unit. Study approval was obtained from the institution's investigational review board prior to enrollment of participants. Data collection was completed over 16 months.
A method-comparison design was used to compare results of the Nurse Dysphagia Screen to results of SLP dysphagia evaluation. Each subject served as his or her control, with both dysphagia screens (nurse, SLP) occurring within 2 hours of each other during the first 48 hours after admission.
The Nurse Dysphagia Screen tool tested in this study was a 16-item assessment tool (see Table 1). The screen was rated as pass or fail, with a failure occurring if any screening item was scored as "yes." Patients who failed the nursing screen remained NPO until evaluated by an SLP. Patients passing the nursing screen had a diet advanced per the institution's stroke protocol.
The SLP dysphagia evaluation was performed by one of four certified SLP personnel using a standardized swallowing evaluation within 48 hours of a patient's hospital admission. After reviewing the medical record, the SLP performed a physical assessment that included a cognitive screening to assess feeding safety, a complete oral motor examination, and an assessment of oral and pharyngeal muscle function. Reflexive/volitional swallow trigger function also was tested. Swallowing trials then were performed with various food consistencies, from liquids to solids, to allow assessment of airway safety during feeding and the success of compensatory strategies/alterations in feeding position. The final report of the SLP included determination of dysphagia and, if present, what types of food and liquids would be safe for the patient to ingest. Findings of the evaluation were recorded in the patient's medical record, along with orders for dietary intake.
A convenience sample of patients admitted to the neurological and neurological intermediate units was eligible for the study. Inclusion criteria included medical diagnosis of stroke, age 18 or older, and ability to follow commands. Exclusion criteria included individuals who were NPO for any reason other than swallowing problems, history of previous swallowing problems, mechanical ventilation and/or intubation for more than 24 hours during the current admission, and inability to follow commands.
Investigators were trained in proper use of the Nurse Dysphagia Screen tool prior to the start of data collection by a neurology clinical educator and a certified speech and language pathologist with extensive experience with stroke. All investigators were nurses with 5-20 years of experience caring for neurology inpatients.
Consenting patients were evaluated with the Nurse Dysphagia Screen by one of six study investigators. Following the standardized SLP assessment guidelines, all participants were evaluated by SLP within 2 hours of the Nurse Dysphagia Screen evaluation.
Data were summarized using descriptive statistics. Sensitivity and specificity of the Nurse Dysphagia Screen were calculated using standard formulas. Sensitivity was calculated as the number of true positives (true positives + false negatives) (Kirkwood & Sterne, 2003; Larsen, 1986). Specificity was calculated as the number of true negatives (true negatives + false positives).
The study included 49 patients with an average age of 71.7 (SD [+ or -] 13.5); 25 subjects were female and 24 were male (see Table 2). The majority of the strokes were identified as ischemic in origin (n=35, 71%). SLP found 18 participants (37%) to have a positive dysphagia screen (see Table 3), resulting in some type of dietary restriction. The Nurse Dysphagia Screen was positive in 16 of 18 patients screened positive by SLP. The Nurse Dysphagia Screen was negative in 28 of 31 patients screened as negative by SLP. Sensitivity and specificity of the Nurse Dysphagia Screen were 89% and 90%, respectively.
This study was designed to evaluate an institutionally developed nurse dysphagia screening tool to identify patients at high risk for swallowing difficulties following acute stroke. The Nurse Dysphagia Screen was developed by a multidisciplinary team to create a more pragmatic screening tool that could be used easily by clinical nurses. The new tool combined features from several existing screening tools and assessment components used by SLP in the dysphagia screening process.
Use of the Nurse Dysphagia Screen correctly identified the majority of individuals who were determined by SLP assessment to have swallowing problems (sensitivity=89%). In addition, the Nurse Dysphagia Screen correctly identified the majority of individuals without swallowing problems (specificity=90%). These sensitivity and specificity values compare very favorably to published results of other dysphagia nurse screening tools and, in most cases, had better sensitivity and specificity (Daniels et al., 2012; Donovan et al., 2013; Schepp et al., 2012; Westergren, 2006).
The excellent sensitivity and specificity results found in this evaluation may have been due to careful use of the screening tool by study investigators. Different results may occur with clinicians who have less experience with dysphagia screening. Another limitation in this study was the failure to evaluate intra- and inter-rater reliability.
The screening tool evaluated in this study can be used easily by clinical nurses to assess swallowing difficulties in patients following acute stroke. Identification of patients at risk for swallowing difficulties can help decrease incidence of aspiration pneumonia. The order of assessment elements in the Nurse Dysphagia Screen allows rapid determination of any need to withhold food and fluids due to a patient's decreased alertness or cognition, speech abnormalities, or difficulties managing secretions. Positive findings in any of these areas result in immediate action by the nurse without having to perform additional swallowing tests on all patients.
Recommendations for Future Research
Future studies should evaluate sensitivity and specificity of this screening tool when used by a larger number of clinical nurses. Of particular importance would be evaluation of the tool's use by nurses inexperienced with patients following stroke. In addition, studies should determine if scoring with the Nurse Dysphagia Screen is similar when the tool is used sequentially by the same person (intra-rater reliability) or by two different nurses (inter-rater reliability).
In this study, clinicians using the Nurse Dysphagia Screen identified the majority of patients with swallowing problems as determined by SLP assessment (sensitivity=89%). This easy-to-use dysphagia screening tool may be valuable in preventing complications of aspiration in patients following stroke.
Jo Cummings, RN, is Staff Nurse, Medical Unit, Munroe Regional Medical Center, Ocala, FL. Donovan Soomans, BSN, RN, is Staff Nurse, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Jennifer O'Laughlin, RN, is Staff Nurse, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Valerie Snapp, RN, is Staff Nurse, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Amy Jodoin, BSN, RN, is Staff Nurse, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Heather Proco, LPN, is Staff Nurse, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Mindy Archer, MA, CCC-SLP, is Speech and Language Pathologist, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Donna Rood, BA, RN, CCRN, is Clinical Educator, Medical Unit, Munroe Regional Medical Center, Ocala, FL.
Acknowledgments: Special thanks to Marianne Chulay, PhD, RN, FAAN, for assistance with study design, data analysis, and manuscript preparation, and to Janice Ulmer, PhD, RN, for manuscript review.
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TABLE 1. Elements on the Nurse Dysphagia Screen Tool (A failed screen occurs when any item evaluated is scored with a yes) Step 1. Before drinking, feeding, or giving oral medications, observe the following Decreased alertness or cognition  No  Yes--stop screening and make NPO Need to suction secretions  No  Yes--stop screening and make NPO Drooling  No  Yes--stop screening and make NPO Wet voice or breath sounds  No  Yes--stop screening and make NPO Slurred or dysarthric speech  No  Yes--stop screening and make NPO Whispered or hoarse voice quality  No  Yes--stop screening and make NPO Step 2. Ask the patient to swallow; ask the patient to cough: Absent dry swallow  No  Yes--stop screening and make NPO Weak or absent cough  No  Yes--stop screening and make NPO Step 3. Give the patient 5 mL of water via a spoon and repeat four more times. Observe for the following: Cough before, during, or after  No  Yes--stop screening swallow and make NPO Shortness of breath  No  Yes--stop screening and make NPO Throat clearing before, during, or  No  Yes--stop screening after swallow and make NPO Wet or gurgly voice quality  No  Yes--stop screening and make NPO Step 4. Give the patient 100 mL of water via a cup. Observe for the following: Cough before, during, or after  No  Yes--stop screening swallow and make NPO Shortness of breath  No  Yes--stop screening and make NPO Throat clearing before, during, or  No  Yes--stop screening after swallow and make NPO Wet or gurgly voice quality  No  Yes--stop screening and make NPO TABLE 2. Characteristics for 49 Patients Evaluated with the Nurse Dysphagia Screen and by Speech and Language Pathology after Acute Stroke Age (mean [+ or -] SD years) 71.7 [+ or -] 13.5 Gender Male n = 24 Female n = 25 Stroke Diagnosis Ischemic n = 36 Hemorrhagic n = 1 Transient ischemia attack n = 7 Not diagnosed n = 5 TABLE 3. Patient (N=49) Results for Dysphagia Screen with a Standardized Speech and Language Pathology (SLP) Screen (clinical gold standard) and the Nurse Dysphagia Screen Nurse Dysphagia Screen * Positive Negative Totals SLP Dysphagia Positive 16 2 18 Screen Negative 3 28 31 Totals 19 30 * Sensitivity = the number of true positives / (true positives + false negatives) = 16/(16 + 2) = 89% Specificity = the number of true negatives / (true negatives + false positives) = 28 / (28 + 3) = 90%
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|Title Annotation:||Research for Practice|
|Author:||Cummings, Jo; Soomans, Donovan; O'Laughlin, Jennifer; Snapp, Valerie; Jodoin, Amy; Proco, Heather; A|
|Date:||Jul 1, 2015|
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