[en] This project has assessed the relationship between cardiopulmonary (CPR) resuscitation quality metrics and carbon dioxide (CO2) levels in out-of-hospital cardiac arrests, in order to determine if CO2 variations are due to specific changes in the way the CPR is provided. To carry out this project a database has been generated from another one which contains records of out-of-hospital cardiac arrests. This new database is composed of 480 segments of a few minutes of duration from 161 different patients. Each segment belongs to a compression interval preceded and followed by about 20 seconds which contain compression free sections, and has the capnography signal registered without any interruption. An algorithm developed in the investigation group has been used to detect the instants of ventilations in the capnography signal, making some adaptations on it to make it detect the instants and values of EtCO2 (End-tidal CO2). Those detected values have been manually revised using a graphical interface following some specific criteria. On the other hand, different CPR metrics related to thoracic compressions have been calculated from the compression interval. Then a graphical interface has been designed as a tool for analyzing segments, which allows for assessing the linear relationship between EtCO2 values and each of the calculated metrics by means of scatter plots and Pearson correlation coefficients (ρ). Segments of the whole database have been analyzed, obtaining plots for the different metrics with very scattered points and very low values of ρ (generally under 0.25), which implies very little linearity. Segments have also been studied separately, obtaining in this case very variable values of ρ, some of them getting even very close to the unit (with a ρ above 0.75), which implies a high linearity. Even in such cases, it is not possible to predict a specific value of EtCO2 using a specific value of the CPR metric. Therefore, it can be concluded that there is no significant linear relationship between EtCO2 and CPR metrics. For this reason, further studies are necessary to determine which specific factors (age, body mass index, cause of arrest…) influence the relationship between CPR metrics and EtCO2.

[eu] Proiektu honetan bihotz-biriketako berpiztearen (BBBaren) kalitate metriken eta karbono dioxido (CO2) mailen arteko erlazioa aztertu da ospitale-kanpoko bihotz-biriketako geldialdi kasuetan. Era honetan, CO2-aren aldaketak, BBBa aplikatzeko moduaren aldaketekin bat datozen aztertu da. Proiektua burutzeko, berezko datu base bat sortu da ospitale-kanpoko bihotz-biriketako erregistroz osatutako beste datu base handiago batetik abiatuz. Datu base berri honek minutu gutxi batzuetako iraupena duten 480 segmentu ditu. Segmentu hauek 161 paziente desberdinetatik atera dira. Segmentu bakoitzak hurrengo patroia jarraitzen du: bularraldeko sakadik gabeko 20 segundoko tartea, sakadak dituen tarte bat, eta beste sakadik gabeko 20 segundoko tartea. Gainera segmentu bakoitzak etenik gabe erregistratutako kapnografia seinalea dauka. Kapnografia seinalean aireztapenen uneak detektatu dira ikerkuntza taldean garatutako algoritmo bat erabiliz. Algoritmo hori moldatu egin da EtCO2 (End-tidal CO2) uneak eta balioak kalkulatzeko. Detektatutako une horiek eskuz birpasatu dira interfaze grafiko bat erabiliz eta irizpide zehatz batzuen arabera. Bestalde, sakadak dituzten segmentuen tarteentzat BBBaren bularraldeko sakadei dagozkien metrika desberdinak kalkulatu dira. Gero, interfaze grafiko bat diseinatu da segmentuen analisia burutzeko. Interfaze grafiko horrek, dispertsio diagramen eta Pearsonen korrelazio koefizienteen (ρ) bidez, BBBaren kalitate metrika bakoitzaren eta EtCO2-aren arteko erlazio linealaren azterketa ahalbidetzen du. Datu basearen segmentuak multzo bat bezala aztertu dira, diagrametan dispertsio handia eta ρ balio oso baxuak (oro har 0.25etik beherakoak) lortuz. Horrek linealtasun baxua adierazten du. Segmentuak banan-banan aztertu dira ere. Kasu honetan, ρ-ren balio aldakorrak lortu dira. Zenbait segmentutan ρ-ren balio altuak lortu dira (0.75etik gorakoak) linealtasun handia adieraziz. Hala eta guztiz ere, kasu horietan ez da posible EtCO2 balio bat zehaztea metrikaren balio batetik abiatuz. Beraz, ondoriozta daiteke ez dagoela erlazio lineal esanguratsurik EtCO2-aren eta BBBaren metriken artean. Horregatik, mota honetako lan gehiago egin behar dira BBBaren kalitatearen eta EtCO2 balioaren arteko erlazioan influentzia duten faktoreak (adina, gorputzeko masa indizea, bihotz-biriketako geldialdiaren jatorria …) zehazteko.