Evidence Based Practice Presentation

Transcription

1 Evidence Based Practice Presentation When obtaining secretions for respiratory virus screening in children are nasal swabs as effective in achieving an accurate diagnosis, or does nasal pharyngeal aspirate remain the best method? Ashley Phillips (427291) Ambulatory Care 1 10 th December 2008

2 Who Should Be Screened For Respiratory Viruses? Not all children are screened for respiratory viruses on arrival to the SSAA in Ninewell s Hospital Dundee. Children with underlying health problems such as the Immunocompromised are routinely swabbed for respiratory viruses if they present with a temperature or any respiratory symptoms. If the child is to be discharged from the SSAA no respiratory screen usually takes place. However due to the recent H1N1 virus outbreak, more respiratory screens are being requested by Health Professionals. Despite the child being discharged home. All children who are admitted to the ward with respiratory symptoms have nasal brushings or an NPA obtained.

3 Benefit Of Respiratory Virus Screening Diagnosis of virus. Relevant treatment given to treat virus if required. Cohort nursing of patients with same virus. Which can alleviate the pressure on nursing staff. Relevant infection control measures. (ie( face masks) Reassurance to parents of unwell child this is especially relevant at present with the H1N1 virus.

4 How to Obtain Nasal Pharyngeal Aspirate To Obtain nasal pharyngeal aspirate a small sterile catheter is inserted into the posterior nasopharynx to a distance of cm. Using suction a small amount of the secretions are aspirated as the catheter is slowly withdrawn from the patient. The sample is then dispensed into the collection pot mixed with 3-53 mls of viral transport medium. (Stensballe 2002). nurse-to-be08.blogspot.com/2006_11_01_archive...

5 How To Obtain Nasal Swabs Nasal brushing is less invasive than nasal pharyngeal aspirates. The dry sterile swab is inserted again into the nasal cavity of the patient and the swab. is wiped along the sides and high up in the nasal passage (approx 2 cm.) The tip of the swab is then broken off carefully to ensure the tip is not contaminated by fingers and then inserted into 3-53 mls of viral transport medium. (Macfarlane 2005). cimen_collection_...

6 Rationale For Question To establish if Nasal Swabs are as effective as Nasal Pharyngeal Aspirate (NPA) when testing for respiratory viruses. At Tayside Children s s Hospital SSAA in Ninewell s respiratory virus screening is being carried out predominantly by way of nasal swabs. However there is some concern with health professionals that these are not as accurate as our previous method of obtaining samples which was NPA. Which has resulted in the use of both methods. Although nasal brushings are proving to be less stressful for the children who require respiratory virus screening.

7 Research Question PICO Format When obtaining secretions for respiratory virus screening in children are nasal swabs as effective in achieving an accurate diagnosis or does nasal pharyngeal aspirate remain the best method? Patient Group Intervention Comparison Outcome Children with respiratory symptoms. Nasal swabs. Nasal pharyngeal aspirate. Accurate diagnosis of a specific respiratory virus.

8 Search Strategy Search terms Children with respiratory illness. Nasal pharyngeal aspirate / NPA. Nasal swabs. Viral respiratory screen. Inclusion Criteria All articles written in the English Language. Articles available electronically via Scottish e-library e / Athens. Articles available at University of Dundee Medical and Nursing library. l Exclusion Criteria Articles written prior to Articles which include adults in study. Articles which relate to specific chronic conditions i.e Cystic Fibrosis.

9 Databases Searched and Results Database searched Ovid Medline Joanna Briggs Institute Ebsco Cinahl BMJ Google Scholar Pubmed Articles Dated From Week Week Week No Date No Date No Date Results 2 articles 0 articles 0 articles 6 articles. 237 articles 28 articles 3 articles were selected. Other articles were disregarded due to: Inclusion of other diagnostic tests such as throat swabs Inclusion of adults in study Focus on patients with a chronic illness Articles specific to RSV testing only Articles published prior to 2000

10 Research Article Selected Article 1 HEIKKINEN, T et al., Nasal Swab versus Nasopharyngeal Aspirate For Isolation of Respiratory Virus. Journal of Clinical Microbiology. Nov. 2002, p.p A Diagnostic study carried out at The Department of Paediatrics Turku Hospital, Finland, Between October 1999 June The study included all children hospitalised with signs and symptoms of URTI. A total of 230 children were included in the study, ages ranged from 12 days to 15 years. The aim of the study was to determine whether nasal swabs were as a accurate as NPA when screening for respiratory viruses.

11 Research Article Selected Article 2 SUNG, R.Y.T et al., Comparative Study of Nasopharyngeal Aspirate and Nasal Swab Specimens For Diagnosis of Acute Viral Respiratory Infection. Journal of Clinical Microbiology. Sept. 2008, p.p A diagnostic test study carried out at The University affiliated Prince of Wales Hospital in Hong Kong. The study was carried out from November October The study included children < 5 years admitted to hospital with a hour or less history of acute respiratory infection. The aim of the study was to compare the usefulness of Nasal swabs and NPA s for respiratory viruses.

12 Research Article Selected Article 3 ABU-DIAB A. et al., Comparison between Perinasal Flocked Swabs and Nasopharyngeal Aspirates for Detection of Common Respiratory Viruses in Samples from Children. Journal of Clinical Microbiology. July 2008, p.p The prospective study was carried out between November 2006 and January 2007 at Carritas Baby Hospital Bethlehem. 455 children under 5 years who were admitted with respiratory infections were recruited to the study. The aim of the study was to compare the use of pernasal flocked swab samples with the use of nasopharangeal aspirate (NPA) samples for the detection of respiratory viruses.

13 Critical Appraisal Tool Critical appraisal skills programme (CASP) tool (2004). ( tm) The articles were critically appraised using the diagnostic test critical appraisal tool. This tool was chosen due to the studies comparing two diagnostic tests to diagnose respiratory viruses. 12 questions to help make sense of a diagnostic study.

14 Diagnostic Test Critical Appraisal Tool Article 1 Article 2 Article 3 1. Was there a clear question for the study to address? Yes. To determine the usefulness of nasal swabs when diagnosing respiratory viruses. Yes. To compare the usefulness of Nasal swabs and NPA when diagnosing respiratory viruses. Yes. To compare the use of Pernasal Flocked Swabs and NPA when diagnosing respiratory viruses. 2. Was there a comparison with an appropriate reference standard? Yes. To compare the efficacy of nasal swabs compared with NPA. Yes. Comparison of the usefulness of Nasal swab and NPA. Yes. To compare the performance of Pernasal Flocked Swabs to NPA. 3. Did all patients get the diagnostic test and the reference standard? Yes. 230 children aged between 12 days 15 years were enrolled in the study all patients received both NPA and NS. Yes. 475 children aged < 5 years were enrolled in the study all patients in the study received both NPA and NS. Yes. 455 children were enrolled in the study and all received both Pernasal flocked Swabs and NPA.

15 Diagnostic Test Critical Appraisal Tool Article 1 Article 2 Article 3 4. Could the results of the test of interest have been influenced by the results of the reference standard? Yes. Blinding of staff obtaining the test samples was not possible due to the nature of obtaining the samples. However blinding could have been achieved by the laboratory staff who tested the samples. But there is no reference to this in the article. Bias could be reduced if the samples had been processed independently. Yes. Blinding of staff obtaining the test samples was not possible due to the nature of obtaining the samples. No blinding was mentioned in the article with regards to laboratory staff processing the samples. This could have been considered to minimise bias. Yes. Blinding of staff obtaining the test samples was not possible due to the nature of obtaining the samples. As with the other two articles no blinding has been considered when the samples have been processed in the laboratory so again the study has an increased risk of bias.

16 Diagnostic Test Critical Appraisal Tool Article 1 Article 2 Article 3 5. Is the disease status of the tested population clearly described? No. Article states all children aged 10 months to 15 years with signs and symptoms of an upper respiratory tract infection. Definition is not clear. Does not state disease stage ie. Length of onset. Yes. Clearly defines. All children < 5 years admitted with sudden onset < 36 hrs of acute respiratory symptoms with one or more of the following symptoms: Rhinorhoea,, cough, sore throat, earache, hoarseness, stridor, dyspnoea with or without fever. No. Article states all children aged between a few days and 5 years with respiratory tract illness. No other information on length of onset or morbidity given. 6. Where the methods of performing the test described in sufficient detail? Yes. A protocol was in place all the children received exactly the same method of obtaining the sample and this is clearly defined. Samples were then sent to the lab for viral culture. Yes. Trained nurses carried out the sample collection and the method of obtaining the sample is clearly defined. Samples were then subjected to 3 tests viral culture, IF and PCR in the lab. Yes. Article states well- trained nurses obtained the sample and the technique is clearly defined. Samples were then subjected to direct fluorescent-antibody assay (DFA) in the lab.

17 Diagnostic Test Critical Appraisal Tool Article 1 Article 2 Article 3 7. What are the results? 122 (53%) of the children tested tested +ve for a respiratory virus 73% of these viruses were detected by both NPA and NS. 19% were detected by NPA only and 7% by NS. No significant differences between NPA and NS were observed when testing for almost all of the respiratory viruses except for RSV. Rate of detection for RSV was significantly higher in (NPA 97% NS 76%) p= No specificity value documented. Results are clearly documented in a table. 89% of the children tested tested +ve for a respiratory virus. 3 laboratory virus screens were carried out on each sample PCR, IF, Culture data is presented clearly for each test in table form. Specificity and sensitivity was carried out for each virus and each test. Overall sensitivity was significantly higher for virus detection on NPA,s.67 IF,.82 Culture,.91 PCR. NS.48 IF,.69 Culture,.81 PCR. (all p<0.01). RSV detection was significantly higher in NPA. NS results were lower but sensitivity increased with PCR test. 320 of the 455 samples collected by NPA and NS were +ve+ ve.. 4 samples were +ve+ by NPA and ve by use of NS 1 sample was +ve+ by NPA but sample was insufficient on NS. Sensitivity, Specificity was carried out for each virus tested. Overall sensitivity was 98.5% and specificity was 100% for the NS. A p-p value was also carried out for each test p= This study found no significant difference in results for NPA and NS when detecting RSV.

18 Diagnostic Test Critical Appraisal Tool Article 1 Article 2 Article 3 8. How sure are we about the results? No confidence interval have been documented. However large study size 250 children. A wide age range was included in the study 12 days 15 years. Results seem accurate. Study has 95% confidence limits. Large study size 475 children. However study only looked at children 5 years and under. No Confidence limits are documented in this article. Large sample size.455 children included in study. However study focused on children <5 years. 9. Can the results be applied to your patients/ the population of interest? Yes. Results can be applied to my area of work as patients involved in study are of a similar age and in Ninewell s we see a large number of patients with respiratory illness. Yes. Results can be applied to my area of work as patients involved in study are of a similar age and in Ninewell s we see a large number of patients with respiratory illness. Yes. Results can be applied to my area of work as patients involved in study are of a similar age and in Ninewell s we see a large number of patients with respiratory illness.

19 Diagnostic Test Critical Appraisal Tool Article 1 Article 2 Article Can the test be applied to your patient or population of interest? Yes. NS are less invasive than NPA and cost effective they are widely used in Ninewells and samples are routinely cultured for viruses. Yes. NS and NPA are both used in Ninewell s when obtaining samples for respiratory screens and are cultured for viruses. However PCR and IF tests are not routinely obtained as are expensive. Yes. Pernasal flocked swabs and NPA are available for use in Ninewells.. However viral swabs are not routinely tested using Direct Fluorescent Antibody Assay (DFA) in Ninewells. 11. Were all outcomes important to the individual or population considered? Yes. Study addressed issues of NPA and NS and sensitivity when detecting viruses Highlighted NS were not always accurate when detecting RSV. Study concludes NS may be utilised to optimise the use of anti viral drugs. Also that NS are quick & easy Yes. Study highlighted that NPA was more sensitive than NS when detecting respiratory viruses. And that NS are inadequate if IF tests are carried out on the sample. However if a PCR is carried out NS becomes as reliable as NPA. Yes. Study describes Pernasal flocked swabs to be as sensitive as NPA and a useful alternative. Also highlights PFS to be a more rapid less invasive method to obtain secretion with minimal training required and no special equipment required.

20 Diagnostic Test Critical Appraisal Tool 12, Impact of using this test on patients in Ninewells Hospital. Children are less distressed when secretions are being obtained by nasal swabs as test is less invasive than obtaining an NPA. Nursing staff are able to obtain nasal swabs without having the need of a second pair of hands to restrain the child for the procedure e as is required with NPA. Cost of pernasal swabs are cheaper as only the swab is required for test whereas with NPA suction is required which is single patient t so has to disgarded and replaced after each patient. Obtaining secretions with a nasal swab is quicker.

21 Answer When obtaining secretions for respiratory virus screening in children are nasal swabs as effective in achieving an accurate diagnosis or does nasal pharyngeal aspirate remain the best method? YES

22 Implication of Study Results on Practice Flocked nasal swabs are currently in use at Ninewell s hospital along with NPA s the studies discussed in this presentation overall supports the use of nasal swabs and the results of the study which used flocked nasal swabs provided evidence that this method is as a reliable as NPA for respiratory virus screening. These studies will w provide reassurance to health professionals that nasal swabs can be as effective as NPA. The studies have also highlighted that nasal swabs are less invasive upsetting and distressing for the child as an APNP it is my responsibility to act as an advocate for the child and to educate other professional of the accuracy of nasal swabs if used correctly. Further training for staff. Staff are now more aware of the importance of a good technique when obtaining Pernasal swabs. Newly qualified nursing staff were not applying the swab high enough into the nasal passage thus causing negative results.

23 Any Questions?

24 References ABU-DIAB, A. et al.,2008. Comparison between Pernasal Flocked Swabs and Nasopharyngeal Aspirates For Detection of Common Respiratory Viruses in Samples fro Children. Journal of Clinical Microbiology, July 2008, pp CASP, Questions to help you make sense of a diagnostic test study. Oxford:Public Health Resource Unit. (Accessed on 30/10/2009.) HEIKKINEN, T. et al., Nasal Swab versus Nasopharyngeal Aspirate for Isolation of Respiratory Viruses. Journal of Clinical Microbiology, November 2002, pp MACFARLANE, P. et al., RSV testing in Bronchiolitis: which sampling method is best. Archive of Childhood Diseases, 2005; 90 pp

25 References STENSBALLE, L.G. et al., Comparison of nasopharyngeal aspirate and nasal swab specimens for detection of respiratory syncytial virus in different settings in a developing country. Tropical Medicine and International Health. 7 (4). pp SUNG, R.Y.T. et al., Comparative Study of Nasopharyngeal Aspirate and Nasal Swab Specimens for Diagnosis of Acute Viral Respiratory Infection. Journal of Clinical Microbiology, September 2008, pp CANTERBUTY DISTRICT HEALTH BOARD Specimen collection and transportation. New Zealand National Measles Laboratory. ort.htm Accessed on 4/11/2009.