Role of Pulse Co-oximetry for Detecting Carbon Monoxide Poisoning in the Prehospital Emergency Medical Service Setting (CO-OX)

Role of Pulse Co-oximetry for Detecting Carbon Monoxide Poisoning in the Prehospital Emergency Medical Service Setting

Role of Pulse Co-oximetry in Prehospital Emergency Medical Service Management of Suspected Carbon Monoxide Poisoning : A Prospective Multicenter Study.

The RAD-57 pulse CO-oximeter is a lightweight device allowing non-invasive measurement of blood carboxyhemoglobin. Previous studies comparing RAD-57 measurements (SpCO) to standard laboratory blood gas analysis (COHb) have reported contradictory results. the RAD-57 pulse CO-oximeter could be useful as a first-line screening test for acute CO poisoning, enabling rapid detection and management of patients with suspected CO poisoning in the prehospital emergency setting This study assesses the diagnostic value of pulse CO-oximetry, comparing SpCO to standard laboratory blood measurement for prehospital management of patients with suspected carbon monoxide (CO) poisoning.

Transcutaneous SpCO will be obtained using the RAD-57 simultaneously with blood sampling for laboratory blood gas analysis, at the time of prehospital management by emergency medical services. The diagnostic performance of SpCO for the screening of CO poisoning will be determined using ROC curve analysis, and Blood COHb levels >5% and 10% as the reference standard for CO poisonning for non-smokers and smokers respectively. Correlation between SpCO and COHb will be assessed using Bland and Altman's method.

CO poisoning, CO-oximetry, Pulse oximetry, Carbon monoxide saturation (SpCO), Emergency Department, Sensitivity, Specificity

SpCO measurement (Experimental) : Non invasive pulse CO-oximetry will be carried out in all patients simultaneously with venous blood sampling for standard laboratory blood gas analysis, at time of prehospital management by emergency medical services COHb measurement (Active comparator) : Blood carboxyhemoglobin testing will be carried out in all patients

SpCO measurement (Experimental) Non invasive pulse CO-oximetry will be carried out by prehospital emergency nursing staff trained in the use of the Rad-57 pulse CO-oximeter (Masimo, Inc., Irvine, CA, USA), using the adult sized sensor (Sensor, Rev. B) placed on the 3rd or 4th digit, according to manufacturer recommendations. Nail polish will be removed if necessary. SpCO was expressed in total percentage of hemoglobin.

COHb measurement (Active Comparator) Venous blood will be collected into EDTA treated tubes (Beckton Dickinson) prehospitally and sent to the toxicology laboratory for further carboxyhemoglobin testing. Blood carboxyhemoglobin will be analyzed by derivative spectrophotometry using an automated CO-oximeter (IL 682, Instrumentation Laboratory SpA V.le Monza 338-20128 Milan, Italy). Blood carboxyhemoglobin will be detected within a range of 0-100% and accuracy of 0.5% and reported as percentage of total haemoglobin.

Inclusion criteria: Patient aged 18 years or older Patient managed by prehospital emergency medical services. Patient with a suspected CO exposure presenting or not with clinical signs of CO poisoning Exclusion criteria: Patient for whom venous blood sampling cannot be obtained prehospitally Patient for whom SpCo measurement cannot be performed prehospitally (cardiac arrest, peripheral vasoconstriction)