A CCURACY OF P ARAMEDIC D IAGNOSIS OF A CUTE C ARDIOGENIC P ULMONARY O EDEMA A prospective diagnostic audit of 1,

1. ACCURACY OF PARAMEDIC DIAGNOSIS OF ACUTE CARDIOGENIC PULMONARY OEDEMAA prospective diagnostic audit of 1,334 patients Emma Jenkinson*, Malcolm Woollard**, Robert Newcombe†, Iain Robertson-Steel†† *Heartlands Hospital/West Midlands Ambulance Service, **Faculty of Pre-hospital Care Research Unit, †Medical Statistics Department, University of Cardiff, ††West Midlands Ambulance Service NHS Trust United Kingdom

2. psychiatric haematology lungs cardiac trauma renal BACKGROUND RESPIRATORY DISTRESS

3. PATHOPHYSIOLOGY OF LVF

4. CPAP IN LVF “…single greatest advance in the management of these [LVF] patients in the past decade…” Cohen Solal et al 1, 2004 CPAP is effective in patients with pulmonary oedema who remain hypoxic despite maximal medical treatment BTS Guidelines 2, 2002 Some UK ambulance services are looking to introduce CPAP for paramedic use, one service already has.

5. PRE-HOSPITAL DIAGNOSIS OF ACPO • Seven main studies 3 • Overall error rates 9-23% • Additional study found 92% accuracy 4 • Paramedic identification of common lung sounds found to be unreliable in 40% of cases 5

6. STUDY AIM A prospective diagnostic audit to assess the accuracy of paramedic diagnosis of acute cardiogenic pulmonary oedema

7. DATA COLLECTION • Prospective audit • Population: patients brought to Heartlands (BHH) by West Midlands Ambulance Service (WMAS) • Publicised beforehand • 2 stages, 2 teams to allow for blinding • An estimated 1,300 patients required • Data collected between 4 Dec 05 until 31 Mar 06

8. DATA COLLECTION – STAGE 1 • WMAS PRFs searched to identify patients taken to BHH with: • Diagnosis of ACPO OR • Furosemide given OR • Presenting complaint of respiratory distress OR • Any of the following diagnoses: • Acute asthma  Croup • SOB ?cause  Exacerbation COPD • Chest infection  Pulmonary oedema • Haemoptysis • Excluded if seen by Dr

9. DATA COLLECTION – STAGE 2 • Demographics matched to hospital records to obtain: • Emergency department (ED) diagnosis • (Hospital discharge diagnosis) • Investigator then unblinded • Diagnoses matched

10. DATA ANALYSIS • Two-by-two tables produced in SPSS: • Positive or negative pre-hospital diagnosis of ACPO • Positive or negative ED diagnosis of ACPO • Results then entered into StatsDirect to calculate: • Sensitivity • Specificity • PPV • NPV • PLR • NLR Proportion of patients with ACPO correctly identified by ambulance staff as having ACPO Proportion of patients without ACPO correctly identified by ambulance staff as not having ACPO By how much does the probability of having ACPO increase with a positive pre-hospital diagnosis? How much the probability of ACPO decreases with a negative pre-hospital diagnosis of ACPO

11. Eligible patients (n=1,334) No record (n=102) GP referrals (n=34) Transfer in (n=1) Did not wait (n=16) To primary care (n=19) Patients seen by ED doctor (n=1,162) ED diagnosis not recorded (n=7) Complete data (n=1,155) RESULTS

12. PRE-HOSPITAL DIAGNOSIS: ACPO (n=59) Not ACPO (n=1096) ED DIAGNOSIS: ED DIAGNOSIS: ACPO (n=24) Not ACPO (n=35) ACPO (n=50) Not ACPO (n=1046) Complete data (n=1,155) RESULTS

13. RESULTS 95% Confidence intervals • Prevalence 6.41% 5.06-7.98% • Sensitivity 32.43 % 22.00-44.32% • Specificity 96.76% 95.53-97.73% • Positive predictive value 40.68% 28.07-54.25% • Negative predictive value 95.44% 94.03-96.60% • Likelihood ratio of +ve result 10.02% 6.25-15.58% • Likelihood ratio of –ve result 0.70% 0.58-0.80%

14. RESULTS PARAMEDIC TECHNICIAN (n = 704) (n = 451) • Prevalence 6.39% 6.43% 4.70-8.46% 4.35-9.1% • Sensitivity 46.67 % 10.34% 31.66-62.13% 2.19-27.35% • Specificity 95.30% 99.05% 93.39-96.78% 97.59-99.74% • +ve predictive value 40.38% 42.86% 27.01-54.90% 9.90-81.59% • -ve predictive value 96.32% 94.14% 94.57-97.63% 91.54-96.14% • LR +ve result 9.92% 10.91% 6.14-15.50% 2.78-40.98% • LR –ve result 0.56% 0.91% 0.41-0.70% 0.74-0.97%

15. RESULTS

16. CONCLUSIONS • Sensitivity low, specificity high • A positive diagnosis carried some predictive value • If patients are treated for ACPO by pre-hospital staff this is likely to be appropriate • A large proportion of patients with ACPO are likely to be missed • Further training is required to improve diagnosis

17. REFERENCES Cohen Solal A. et al (2004) Traitement médical de l’insufficance cardiaque aigüe décompensée. Annales de Cardiologie et d’Angéiologie 53: 200-208 British Thoracic Society Standards of Care Committee (2002) Non-invasive ventilation in acute respiratory failure. Thorax57: 192-211 Shapiro S.E. (2005) Evidence review: Emergency medical services treatment of patients with congestive heart failure/acute pulmonary edema: do risks outweight the benefits? J Emerg Nursing 31(1): 51-57 Durham B., Aguilera P., Dale K., Neimen H. (1999) Accuracy of pre-hospital diagnosis of primary respiratory distress. Acad Emerg Med6(5): 474 Widger H.N., Johnson D.R., Cohan S., Felde R., Colella R. (1996) Assessment of lung auscultation by paramedics. Ann Emerg Med28(3): 309-312