Clinical prediction rule of termination of resuscitation for out-of-hospital cardiac arrest patient with pre-hospital defibrillation given.

OBJECTIVE: To derive a clinical prediction rule of termination of resuscitation (TOR) for out-of-hospital cardiac arrest (OHCA) with pre-hospital defibrillation given. METHOD: This was a retrospective multicenter cohort study performed in three emergency departments (EDs) of three regional hospitals from 1/1/2012 to 31/12/2018. Patients of OHCA aged ≥18 years old were included. Those with post-mortem changes, return of spontaneous circulation and receiving no resuscitation in EDs were excluded. A TOR rule was derived by logistic regression analysis based on demographics and end-tidal carbon dioxide level of included subjects with pre-hospital defibrillation given. RESULTS: There were 447 included patients had received pre-hospital defibrillation, in which 148 had return of spontaneous circulation (ROSC), with 22 survived to discharge (STD). Independent predictors for death on or before ED arrival (no ROSC) included EMS call to ED time >20 min and ETCO2 level <20 mmHg from first three sets. A 2-criteria rule predicting death on or before ED arrival by fulfilling both of the independent predictors had a specificity of 0.95 (95% CI 0.90-0.98) and positive predictive value (PPV) of 0.95 (95% CI 0.90-0.98), if 2nd set of ETCO2 was used. The positive likelihood ratio was 10.04 (95% CI 4.83-20.89). CONCLUSION: The 2-criteria TOR rule for OHCA patients with pre-hospital defibrillation had a high specificity and PPV for predicting death on or before ED arrival.

Clinical prediction rule to predict pneumonia in adult presented with acute febrile respiratory illness.

OBJECTIVE: To derive a clinical prediction rule to predict pneumonia in patients with acute febrile respiratory illness to emergency departments. METHOD: This was a prospective multicentre study. 537 adults were recruited. Those requiring resuscitation or were hypoxaemic on presentation were excluded. Pneumonia was defined as new onset infiltrates on chest X-ray (CXR), or re-attendance within 7 days and diagnosed clinically as having pneumonia. A predictive model, the Acute Febrile Respiratory Illness (AFRI) rule was derived by logistic regression analysis based on clinical parameters. The AFRI rule was internally validated with bootstrap resampling and was compared with the Diehr and Heckerling rule. RESULTS: In the 363 patients who underwent CXR, 100 had CXR confirmed pneumonia. There were 7 weighted factors within the ARFI rule, which on summation, gave the AFRI score: age ≥ 65 (1 point), peak temperature within 24 h ≥ 40 °C (2 points), fever duration ≥3 days (2 points), sore throat (-2 points), abnormal breath sounds (1 point), history of pneumonia (1 point) and SpO2 ≤ 96% (1 point). With the bootstrap resampling, the AFRI rule was found to be more accurate than the Diehr and Heckerling rule (area under ROC curve 0.816, 0.721 and 0.566 respectively, p < 0.001). At a cut-off of AFRI≥0, the rule was found to have 95% sensitivity, with a negative predictive value of 97.2%. Using the AFRI score, we found CXR could be avoided for patients having a score of <0. CONCLUSION: AFRI score could assist emergency physicians in identifying pneumonia patients among all adult patients presented to ED for acute febrile respiratory illness.

Prognostication of out-of-hospital cardiac arrest patients by 3-min end-tidal capnometry level in emergency department.

OBJECTIVE: To evaluate the role of initial ETCO2 value in prognostication of OHCA patients in an Asian-Chinese cohort. DESIGN: Prospective cohort study. SETTING: Emergency departments of two regional hospitals in a cluster of Hong Kong. PATIENTS: Patients were recruited prospectively from the local cardiac arrest registry from July 2012 to June 2013. Patients of non traumatic OHCA aged ≥18 years old were included. Patients of OHCA presented with postmortem changes, those who decided for Do Not Resuscitate (DNR), regained pulse before arrival, or those without proper documentation of ETCO2 would be excluded. OUTCOME: Primary outcome was return of spontaneous circulation (ROSC). RESULTS: A 3-min ETCO2 >10mmHg was a predictor of ROSC with OR 18.16 (95% CI 4.79-51.32, p<0.001). The diagnostic accuracy of 3-min ETCO2 >10mmHg to predict ROSC: sensitivity was 0.95 (95% CI 0.89-0.98) while the specificity was 0.27 (95% CI 0.21-0.33). Positive predictive value was 0.40 (95% CI 0.34-0.46) while negative predictive value (NPV) was 0.92 (95% CI 0.82-0.97). Area under ROC curve of 3-min ETCO2 predicting ROSC was 0.80 (95% CI 0.71-0.91). CONCLUSIONS: A 3-min ETCO2 ≤10mmHg was associated with poor prognosis and low chance of ROSC. Low ETCO2 level may have a role to reduce prolonged medically futile resuscitation.

Abrupt rise of end tidal carbon dioxide level was a specific but non-sensitive marker of return of spontaneous circulation in patient with out-of-hospital cardiac arrest.

OBJECTIVE: To evaluate the diagnostic accuracy of an abrupt and sustained increase in end-tidal carbon dioxide (ETCO2) to indicate return of spontaneous circulation (ROSC) during resuscitation of patient with out-of-hospital cardiac arrest. DESIGN: Cross-sectional study. SETTING: Emergency department of two regional hospitals. METHODS: Patients with age ≥18 years old, suffered non-traumatic out-of-hospital cardiac arrest with active resuscitation and endotracheal intubation performed in emergency department, were included. ETCO2 value was charted throughout resuscitation. Time of ROSC was remarked. ETCO2 levels before and after ROSC were compared. Diagnostic accuracy of ETCO2 rise ≥10mmHg, ETCO2 rise ≥20mmHg, and ETCO2 rise to the level ≥40mmHg were evaluated for indicating ROSC. RESULTS: ETCO2 level immediately after ROSC was higher as compared to the value before return of circulation (median ETCO2 was 32mmHg and 41mmHg respectively, p=0.033). With ETCO2 rise ≥10mmHg, the sensitivity was low (33%, 95% CI 22-47%), while specificity was 97% (95% CI 91-99%). Positive and negative predictive values were 83% (95% CI 62-95%) and 74% (95% CI 66-81%) respectively. The diagnostic accuracy was higher in cardiac arrest with presumed non-cardiac etiology (sensitivity 45%, specificity 100%) as compared to those with cardiac etiology (sensitivity 18%, specificity 97%). CONCLUSIONS: The feature of an abrupt rise of ETCO2 was a specific but non-sensitive marker of ROSC in patient with out-of-hospital cardiac arrest.