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- Ölander, Carl-Henrik
(författare)
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Extracorporeal cardiopulmonary resuscitation, selection and candidacy
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Extracorporeal cardiopulmonary resuscitation (ECPR) is an exclusive treatment using extracorporeal membrane oxygenation (ECMO) in refractory cardiac arrest (CA). Treatment is associated with risk of serious complications, including neurologic impairment and renal failure. Success of treatment is dependent on appropriate selection of candidates. The aim of this thesis was to investigate the role of end-tidal carbon dioxide (ETCO2), as a selection criterion for ECPR. Moreover, to define and describe the potential ECPR-cohort in Sweden and investigate conditions for a national ECPR-program.Experimental porcine models of CA were used in studies I and II. CA was induced, and cardiopulmonary resuscitation (CPR) was performed. Physiological parameters, biochemical markers and histology were evaluated in relation to ETCO2. In study I, ECMO was started at a predetermined time of CPR. Levels of ETCO2 during CPR was found to be associated with the extent of cerebral and renal injury following ECPR. In study II, the same model was used. However, start of ECMO was triggered by a predetermined threshold of ETCO2 during CPR. Results suggest that ETCO2 could be used as a marker for brain injury following ECPR.Extract from The Swedish Cardiac Arrest Registry formed the data basis for studies III and IV. Internationally proposed selection criterion for ECPR was applied to the data. ECPR-eligible cohorts were defined and described. In study III, data on in-hospital cardiac arrests was assessed. Results showed low numbers of ECPR-eligible patients annually. Estimates of gain of ECPR suggested a limited benefit in survival and neurological outcome, if ECMO was started within 60 min. In study IV, data on out-of hospital cardiac arrests was assessed. Low numbers of candidates suggested that only a minority of ECPR-capable hospitals in Sweden have a population base large enough to justify an ECPR-program.In conclusion, this thesis has demonstrated a correlation between ETCO2 during CPR and the resulting injury in brain and kidney following ECPR. It supports its use as selection criteria for ECPR candidacy. The estimated incidence of ECPR-candidates in Sweden is low. Moreover, calculations on gain of ECPR on survival and neurologic outcome is limited. Selection criteria and geography are the major determinants for ECPR-candidacy.
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| 2. |
- Dreifaldt, Mats, 1959-
(författare)
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Conduits in coronary artery bypass grafting surgery : Saphenous vein, radial and internal thoracic arteries
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A novel technique for saphenous vein (SV) graft harvesting, the No-touch technique (NT), has been developed at the Dept. of Cardiovascular surgery, Örebro University hospital. With NT the SV is harvested with a pedicle of surrounding tissue. This avoids graft spasm and eliminates the need for distension. The surrounding tissue acts as a structural support and is a rich source of vaso-dilating agents. A randomized controlled trial (RCT) has shown a significantly higher patency rate for NT SV grafts compared to SV grafts harvested with conventional technique (CT). This thesis evaluates some of the properties of the surrounding tissue and compares patency rates between NT SV and radial artery (RA) grafts and patency rates for internal thoracic artery (ITA) grafts harvested with and without surrounding tissue. Paper I investigated vasa vasorum (VV) in SV grafts and showed that the NT preserves an intact VV whereas CT does not. This could be one of the mechanisms underlying the improved patency for NT SV grafts. Paper II evaluated VV and associated nitric oxide (NO) in SV and arterial grafts. SV grafts showed a higher number and larger VV, which correlated with NO production, compared to arterial grafts. NT SV grafts showed higher activity for e-NOS compared to CT SV grafts. Paper III is a RCT comparing patency rates between NT SV and RA grafts, three years after surgery, showing a significantly higher patency rate for NT SV grafts. Paper IV is a RCT comparing patency rates for ITA graft harvested with and without surrounding tissue and did not show any difference between graft preparations. In conclusion, the NT for SV graft harvesting preserves an intact vasa vasorum and associated NO production. NT SV grafts show a higher patency rate than RA grafts. Harvesting of ITA with or without surrounding tissue does not affect patency rate.
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