Influence of circulatory shock at hospital admission on outcome after out-of-hospital cardiac arrest

Hypotension after cardiac arrest could aggravate prolonged hypoxic ischemic encephalopathy. The association of circulatory shock at hospital admission with outcome after cardiac arrest has not been well studied. The objective of this study was to investigate the independent association of circulatory shock at hospital admission with neurologic outcome, and to evaluate whether cardiovascular comorbidities interact with circulatory shock. 4004 adult patients with out-of-hospital cardiac arrest enrolled in the International Cardiac Arrest Registry 2006–2017 were included in analysis. Circulatory shock was defined as a systolic blood pressure below 90 mmHg and/or medical or mechanical supportive measures to maintain adequate perfusion during hospital admission. Primary outcome was cerebral performance category (CPC) dichotomized as good, (CPC 1–2) versus poor (CPC 3–5) outcome at hospital discharge. 38% of included patients were in circulatory shock at hospital admission, 32% had good neurologic outcome at hospital discharge. The adjusted odds ratio for good neurologic outcome in patients without preexisting cardiovascular disease with circulatory shock at hospital admission was 0.60 [0.46–0.79]. No significant interaction was detected with preexisting comorbidities in the main analysis. We conclude that circulatory shock at hospital admission after out-of-hospital cardiac arrest is independently associated with poor neurologic outcome.publishedVersio

The association of partial pressures of oxygen and carbon dioxide with neurological outcome after out-of-hospital cardiac arrest: an explorative International Cardiac Arrest Registry 2.0 study

Background Exposure to extreme arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) following the return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA) is common and may affect neurological outcome but results of previous studies are conflicting. Methods Exploratory study of the International Cardiac Arrest Registry (INTCAR) 2.0 database, including 2162 OHCA patients with ROSC in 22 intensive care units in North America and Europe. We tested the hypothesis that exposure to extreme PaO2 or PaCO2 values within 24 h after OHCA is associated with poor neurological outcome at discharge. Our primary analyses investigated the association between extreme PaO2 and PaCO2 values, defined as hyperoxemia (PaO2 > 40 kPa), hypoxemia (PaO2  6.7 kPa) and hypocapnemia (PaCO2  40 kPa with PaCO2  6.7 kPa and neurological outcome. To define a cut point for the onset of poor neurological outcome, we tested a model with increasing and decreasing PaO2 levels and decreasing PaCO2 levels. Cerebral Performance Category (CPC), dichotomized to good (CPC 1–2) and poor (CPC 3–5) was used as outcome measure. Results Of 2135 patients eligible for analysis, 700 were exposed to hyperoxemia or hypoxemia and 1128 to hypercapnemia or hypocapnemia. Our primary analyses did not reveal significant associations between exposure to extreme PaO2 or PaCO2 values and neurological outcome (P = 0.13–0.49). Our secondary analyses showed no significant associations between combinations of PaO2 and PaCO2 and neurological outcome (P = 0.11–0.86). There was no PaO2 or PaCO2 level significantly associated with poor neurological outcome. All analyses were adjusted for relevant co-variates. Conclusions Exposure to extreme PaO2 or PaCO2 values in the first 24 h after OHCA was common, but not independently associated with neurological outcome at discharge.publishedVersio

Kiinteän pilkun laskenta sulautetussa järjestelmässä

Floating-point and fixed-point calculations in an embedded system are the focus of this study; in particular, in this research, an embedded system is defined as a valve positioner (made by Metso Automation) controlled by a microcontroller. Moreover, one of the significant causes of load in a microcontroller is known to be floating-point arithmetic. Thus the aim of this study is to create a fixed-point data type which replaces floating-point arithmetic if fixed-point arithmetic can be proven to reduce the load of the microcontroller, and retain reliable accuracy. In addition to this, a fixed-point data type must be scalable and transferable to various HW/SW-environments. The theoretical part of this thesis is based on a thorough review of earlier research and, moreover, explicates the demanding application environment of a valve package. A valve package consists of an industry valve, an actuator and a valve positioner. This thesis focuses on an ARM-based microcontroller in a valve positioner. The theoretical part explicates the relevant data type's e.g. floating-point numbers, integers and fixed-point numbers and their sizes and structures. A demonstration is given in the experimental section of how a fixed-point data type is created based on the theoretical part with an oscilloscope being used to measure the speed of floating-point and fixed-point arithmetic. Some fixed-point models are explained and one of the previous ones is chosen for further tests. The criteria for a chosen fixed-point model are extensibility and accuracy. A chosen fixed-point model is verified against accuracy and speed. This thesis demonstrates the processes of floating-point and fixed-point calculation as well as their requirements. Finally, the thesis proposes some ideas for further development of fixed-point calculation.Tässä diplomityössä on tutkittu liukuluku- ja kiinteän pilkun laskentaa sulautetussa järjestelmässä. Tässä tapauksessa sulautettu järjestelmä on Metso Automationin valmistama digitaalinen venttiiliohjain, jota ohjaa mikrokontrolleri. Liukulukulaskennan on todettu olevan yksi merkittävä mikrokontrollerin kuormittaja. Tarkoituksena on luoda kiinteän pilkun tietotyyppi ja korvata sillä liukulukulaskenta, jos kiinteän pilkun laskenta pienentää mikrokontrollerin kuormitusta ja omaa hyvän tarkkuuden. Tämän lisäksi kiinteän pilkun tietotyypin tulee olla laajennettava ja olla siirrettävissä erilaisiin HW/SW-ympäristöihin. Diplomityön teoriaosa muodostettiin kirjallisuustutkimuksen avulla. Teoriaosassa esitellään haastavaa sovellusympäristöä, joka on venttiilipaketti. Venttiilipaketin muodostavat teollisuusventtiili, toimilaite ja venttiiliohjain. Venttiiliohjaimessa keskitytään mikrokontrolleriin, joka on ARM-pohjainen. Teoriaosa esittelee asiaan kuuluvat tietotyypit, kuten esimerkiksi liukuluvut, kokonaisluvut ja kiinteän pilkun luvut. Em. tietotyypeistä käydään läpi niiden kokoa ja rakennetta. Diplomityön kokeellisessa osassa muodostetaan kiinteän pilkun tietotyyppi teoriaosasta saatujen tietojen perusteella. Liukuluku- ja kiinteän pilkun laskennan nopeutta mitataan oskilloskoopin avulla. Kokeellinen osa esittelee useita toteutusmalleja, joista valitaan yksi. Kriteerinä valinnalle on sen laajennettavuus ja sen tarkkuus. Valittu kiinteän pilkun toteutusmalli verifioidaan tarkkuuden ja nopeuden suhteen. Tämä diplomityö opettaa ymmärtämään liukuluku- ja kiinteän pilkun laskentaa sekä niiden vaatimuksia. Diplomityön lopuksi kiinteälle pilkulle esitetään jatkokehityssuunnitelma