How accurate is the prehospital diagnosis of hyperventilation syndrome?

Background The literature suggests that hyperventilation syndrome (HVS) should be diagnosed and treated prehospitally. Aim To determine diagnostic accuracy of HVS by paramedics and emergency medical technicians using hospital doctors' diagnosis as the reference standard. Methods A retrospective audit was carried out of routine data using linked prehospital and in-hospital patient records of adult patients (≥18 years) transported via emergency ambulance to two emergency departments in the UK from 1 January 2012–31 December 2013. Accuracy was measured using sensitivity, specificity, positive and negative predictive values (NPV/PPVs) and likelihood ratios (LRs) with 95% confidence intervals. Results A total of 19 386 records were included in the analysis. Prehospital clinicians had a sensitivity of 88% (95% CI [82–92%]) and a specificity of 99% (95% CI [99–99%]) for diagnosing HVS, with PPV 0.42 (0.37, 0.47), NPV 1.00 (1.00, 1.00), LR+ 75.2 (65.3, 86.5) and LR− 0.12 (0.08, 0.18). Conclusions Paramedics and emergency medical technicians are able to diagnose HVS prehospitally with almost perfect specificity and good sensitivity.