ABSTRACT
BackgroundEmergency Medical Services (EMS) have experienced surges in demand as the COVID-19 pandemic has progressed with ambulances services in the UK declaring major incidents due to the risk of care being compromised. COVID-19 specific EMS telephone triage tools have been introduced to help manage demand. There has been no previous evaluation of the accuracy of EMS telephone triage in identifying patients with suspected COVID-19 at risk of serious adverse outcome. We aimed to assess accuracy of EMS telephone triage in identifying patients who need an EMS response and identify factors which affect triage accuracy. MethodPatients who made an emergency call to Yorkshire Ambulance Service between 2nd April and 29th June 2020 and were assessed using an AMPDS pandemic pathway for suspected COVID-19 were linked to Office for National Statistics death registration data, hospital and general practice electronic health care data collected by NHS Digital. Accuracy of decision to dispatch an ambulance was assessed in terms of death or need for organ support at 30 days from the first 999 call. Multivariable logistic regression was used to identify factors associated with false negative and false positive triage. ResultsOf 12, 653 callers included in the study population, 11.1% experienced the primary composite adverse outcome. Using the triage pathway, 16% of callers did not receive an emergency response and they had a lower risk (3.5%) of the primary outcome. Ambulances were dispatched to 4, 230 callers (33.4%) who were not subsequently conveyed to hospital and did not experience the primary outcome (false positive triage). Multivariable modelling found older age and presence of pre-existing respiratory disease were significant predictors of false positive triage. ConclusionEMS telephone triage avoided 16% of calls receiving an emergency ambulance, of whom 3.5% died or needed organ support by 30 days. Telephone triage can therefore reduce the burden of EMS responses but with the cost of a small proportion of patients who do not receive an initial emergency response deteriorating. Research is needed to identify the appropriate balance between over- and under-triage
ABSTRACT
Study ObjectiveTools proposed to triage patient acuity in COVID-19 infection have only been validated in hospital populations. We estimated the accuracy of five risk-stratification tools recommended to predict severe illness and compare accuracy to existing clinical decision-making in a pre-hospital setting. MethodsAn observational cohort study using linked ambulance service data for patients attended by EMS crews in the Yorkshire and Humber region of England between 18th March 2020 and 29th June 2020 was conducted to assess performance of the PRIEST tool, NEWS2, the WHO algorithm, CRB-65 and PMEWS in patients with suspected COVID-19 infection. The primary outcome was death or need for organ support. ResultsOf 7549 patients in our cohort, 17.6% (95% CI:16.8% to 18.5%) experienced the primary outcome. The NEWS2, PMEWS, PRIEST tool and WHO algorithm identified patients at risk of adverse outcomes with a high sensitivity (>0.95) and specificity ranging from 0.3 (NEWS2) to 0.41 (PRIEST tool). The high sensitivity of NEWS2 and PMEWS was achieved by using lower thresholds than previously recommended. On index assessment, 65% of patients were transported to hospital and EMS decision to transfer patients achieved a sensitivity of 0.84 (95% CI 0.83 to 0.85) and specificity of 0.39 (95% CI 0.39 to 0.40). ConclusionUse of NEWS2, PMEWS, PRIEST tool and WHO algorithm could improve sensitivity of EMS triage of patients with suspected COVID-19 infection. Use of the PRIEST tool would improve sensitivity of triage without increasing the number of patients conveyed to hospital.
ABSTRACT
ObjectiveTo assess accuracy of telephone triage in identifying patients who need emergency care amongst those with suspected COVID-19 infection and identify factors which affect triage accuracy. DesignObservational cohort study SettingCommunity telephone triage in the Yorkshire and Humber, Bassetlaw, North Lincolnshire and North East Lincolnshire region. Participants40, 261 adults who contacted NHS 111 telephone triage services provided by Yorkshire Ambulance Service NHS Trust between the 18th March 2020 and 29th June 2020 with symptoms indicating possible COVID-19 infection were linked to Office for National Statistics death registration data, hospital and general practice electronic health care data collected by NHS Digital. OutcomeAccuracy of triage disposition (self-care/non-urgent clinical assessment versus ambulance dispatch/urgent clinical assessment) was assessed in terms of death or need for organ support at 30, 7 and 3 days from first contact with the telephone triage service. ResultsCallers had a 3% (1, 200/40, 261) risk of adverse outcome. Telephone triage recommended self-care or non-urgent assessment for 60% (24, 335/40, 261), with a 1.3% (310/24, 335) risk of subsequent adverse outcome. Telephone triage had 74.2% sensitivity (95% CI: 71.6 to 76.6%) and 61.5% specificity (61% to 62%) for adverse outcomes at 30 days from first contact. Multivariable analysis suggested some co-morbidities (such as chronic respiratory disease) may be over-estimated as predictors of adverse outcome, while the association of diabetes with adverse outcome may be under-estimated. Repeat contact with the service appears to be an important under recognised predictor of adverse outcomes with both 2 contacts (OR 1.77 95% CI: 1.14 to 2.75) and 3 or more contacts (OR 4.02 95% CI: 1.68 to 9.65) associated with clinical deterioration when not provided with an ambulance or urgent clinical assessment. ConclusionPatients advised to self-care or receive non-urgent clinical assessment had a small but non-negligible risk of serious clinical deterioration. The sensitivity and specificity of telephone triage was comparable to other tools used to triage patient acuity in emergency and urgent care. Repeat contact with telephone services needs recognition as an important predictor of subsequent adverse outcomes. What is already known on this topicO_LITelephone triage has been used to divert patients with suspected COVID-19 to self care or for non-urgent clinical assessments, and thereby help mitigate the risk of health services being overwhelmed by patients who require no speficic treatment. C_LIO_LIConcerns have been raised that telephone triage may not be sufficiently accurate in identifying need for emergency care. However, no previous evaluation of accuracy of telephone triage in patients with suspected COVID-19 infection has been completed. C_LI What this study addsO_LIPatients advised to self care or receive non-urgent clinical assessment had a small but non-negligible risk of deterioration and significant adverse outcomes. C_LIO_LITelephone triage has comparable performance to methods used to triage patient acuity in other emergency and urgent care settings. C_LIO_LIAccuracy of triage may be improved by better recognition of multiple contact with services as a predictor of adverse outcomes. C_LI
