Studies on the Aetiology, Quality, and Outcome of Cardiopulmonary Resuscitation: With special reference to resuscitation-associated complications and quality of life after cardiac arrest

Heidi Hellevuo

    Research output: Book/ReportDoctoral thesisCollection of Articles

    Abstract

    For the prognosis of a cardiac arrest patient, it is crucial that all the steps, from recognition of the arrest to the rehabilitation, proceed without delays or disruptions. As part of a high-quality cardiopulmonary resuscitation (CPR), it is important to identify the underlying reason for the arrest in order to allow the selection of specific treatment interventions. Unfortunately, the quality of CPR is often suboptimal. One solution to this problem can be the use of audio-visual feedback devices. Deeper chest compressions correlate with better defibrillation rates and the likelihood of a return of spontaneous circulation but, at the same time, can cause more injuries to the chest and upper abdominal area. The aetiology of in-hospital cardiac arrests on general wards and their preceding vital dysfunctions and subjective antecedents associated with 6-months survival were examined in the first sub-study. In 141 events, the aetiology was determined as cardiac, 73 of which were due to acute myocardial infarction. In 138 cases, the cause was due to a non-cardiac reason; the most common causes were exsanguination (16) and pneumonia (39). No differences were observed in the incidence of objective vital dysfunctions preceding the event between the cardiac and non-cardiac groups (40 % vs. 44 %, p = 0.448). In the cardiac cohort, subjective antecedents were more common (47 % vs. 32 %, p = 0.022). Only monitored or witnessed events, low comorbidity score and shockable primary rhythm were independently associated with 180-day survival. In the second sub-study, the quality of CPR during transportation was analysed. 24 paramedics performed chest compressions on a Laerdal Resusci Anne® manikin first without and then with the guidance of Philips HeartStart MRx defibrillator and with high-quality cardiopulmonary resuscitation (QCPR) feedback device. With the feedback device, compression depth improved from 51 (10) mm to 56 (5) mm (p< 0.001). However, no differences were observed in the chest compression rate (p=0.55) and no-flow fractions (p=0.82). When the mattress effect was taken into account, the real chest compression depth was only 41 (8) mm in non-feedback phase and 44 (5) in feedback phase (p<0.001). In the third sub-study the mattress effect was analysed during ten separate in- hospital resuscitation attempts. The mean chest compression depth in every resuscitation attempt was over 50 mm. When the mattress effect was taken into account and the real chest compression depth was calculated, the real chest compression depth was adequate in CPRs performed on a standard gel mattress and emergency room stretcher, but on an intensive care unit (ICU) air mattress the real chest compression depth fell below 50 mm. The potential association between CPR-related injuries and objectively measured chest compression depth was investigated in the fourth sub-study. The data of 170 separate resuscitation attempts with the details of actual chest compression depths and postresuscitation computed tomography (CT)-scans, thorax X-rays or medical/forensic autopsy findings were analysed. Injuries were found in 32 % of the patients. The majority of the injuries were spontaneously healing rib or sternal fractures. When the mean chest compression depth exceeded 60 mm, the percentage of the injuries increased from 27 to 49 % (p=0.06). With the implementation of 2010 resuscitation guidelines, an increase in the percentage of the injuries was seen from 32 to 40 % (p=0.21). None of the injuries contributed to the death of the patients or affected survival. In the fifth sub-study, the quality of life six months after a successful cardiac arrest and factors that might influence a better outcome were investigated. Altogether 222 patients were admitted to the ICU after a cardiac arrest. After six months 79 (36 %) patients were still alive, and 25 % answered to the follow-up EuroQoL-5 Dimensions (EQ-5D) questionnaire. When the possible factor influencing the quality of life was analysed, the best predictor for a good quality of life after cardiac arrest was a good quality of life prior to cardiac arrest. It can be concluded that in-hospital cardiac arrests are, in most cases, due to cardiac reasons that should be taken into account when considering specific treatment options during or after CPR. The quality of CPR can be improved by using audio-visual feedback devices. The downside of these devices is that when the patient is lying on a compliant surface, the real chest compression depth can be too shallow. Current resuscitation guidelines emphasise high-quality chest compressions with a depth of 50-60 mm. Deeper chest compressions are associated with an increased risk of injuries. The majority of the injuries are spontaneously healing rib of sternal fractures, and life-threatening complications occur infrequently. On the basis of this study, it can be suggested that the maximum depth recommended should be 6 cm because there is no data suggesting that even deeper compressions would be beneficial; however, they are likely to increase the risk of injuries. Patients that survive cardiac arrest have, on the average, a good quality of life six months after the cardiac arrest.
    Original languageEnglish
    Place of PublicationTampere
    PublisherTampere University
    ISBN (Electronic)978-952-03-1711-9
    ISBN (Print)978-952-03-1710-2
    Publication statusPublished - 2020
    Publication typeG5 Doctoral dissertation (articles)

    Publication series

    NameTampere University Dissertations - Tampereen yliopiston väitöskirjat
    Volume315
    ISSN (Print)2489-9860
    ISSN (Electronic)2490-0028

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