ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Extracorporeal membrane oxygenation (ECMO) is becoming a gold standard in acute heart failure, not responsive to inotrops and intra-aortic balloon contrapulsation. This diffusion is due to the possibility to implant it through peripheral cannulation and to perform long-time assistance. ⋯ It is widely accepted that arterial distal cannulation and perfusion of the limb is mandatory, especially for long periods of assistance; but the necessity to implant a distal venous drainage is still discussed. We would like to present our experience on peripheral ECMO where we could avoid venous distal drainage uneventfully.
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In a model of acute lung injury (ALI), previously, we have shown that apneic oxygenation, using an inspiratory O2 fraction (FiO2) of 1.0 combined with extracorporeal arteriovenous CO2 removal (AO-AVCR) maintains adequate arterial O2 and CO2 levels for a prolonged period. However, it is important that FiO2 lower than 1.0 can be used to avoid possible pulmonary oxygen toxicity. In preliminary studies, arterial oxygenation decreased to extreme low levels, when FiO2 <1 was used in apneic oxygenation. ⋯ At the end of the period, the alveolar O2 fraction (FAO2) was 0.89 (0.88-0.89; median and ranges). With FiO2 = 0.5, PaO2 decreased 90% compared with baseline values and FAO2 decreased to 0.07 (0.06-0.07). No atelectasis was visible on computed tomography after either period, and we, therefore, conclude that the alveolar hypoxia was caused by the alveolar N2 accumulation/concentration and subsequently by the O2 depletion.
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Meta Analysis
Use of extracorporeal membrane oxygenation for adults in cardiac arrest (E-CPR): a meta-analysis of observational studies.
Published data on the use of extracorporeal membrane oxygenation (ECMO) as a supportive measure during or immediately after cardiopulmonary resuscitation (CPR) in adults (older than 18 years) shows mixed results. To assess the clinical outcomes of the use of ECMO in this modality and to look for predictors of mortality, we performed a meta-analysis (MA) of individual patients collected from observational studies. An electronic PubMed search restricted to English-language publications between 1990 and 2007, using a consensus restrictive criterion, retrieved 141 titles. ⋯ There was a negative trend in survival when manual CPR lasted >30 minutes without prompt ECMO initiation (OR 1.9; 95% CL, 0.9-4.2). This work confirms the expectations for a better survival when E-CPR is used in younger patients, for shorter periods of time and after expeditious implementation during or immediately after manual CPR. Neurologic sequelae and other major complications, although suspected to be high, are poorly described in the reviewed literature.
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Randomized Controlled Trial
Cardiac output measurement by arterial pressure waveform analysis during optimization of biventricular pacing after cardiac surgery.
Biventricular pacing (BiVP) can optimize cardiac output (CO) in patients after cardiac surgery, so devices that calculate continuous CO from arterial pressure may be a useful tool. We investigated PulseCO for measuring CO during optimization by comparison with aortic flow probe measurement. Seven patients in the Biventricular Pacing After Cardiac Surgery (BiPACS) trial were studied. ⋯ In contrast, changes in mean arterial pressure did not reflect changes in CO (intraclass correlation coefficient = 0.02). Thus, PulseCO can measure continuous CO in open-chest patients after cardiac surgery, whereas underestimating changes occurring across 10-second pacemaker changes. Further studies in the closed chest are indicated.
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Transfusion for hemorrhagic shock can improve oxygenation, but immunoreactions may induce inflammation. Artificial oxygen carriers have been developed to address clinical concerns of infection and stability, but whether an artificial oxygen carrier might induce inflammation is not well known. To address this question, we compared inflammatory reactions after resuscitation with hemoglobin vesicles (HbVs) or red blood cells (RBCs) in a hemorrhagic shock rat model. ⋯ In rats resuscitated with HbVs, mRNA levels of TNF-alpha and HO-1 2 h after resuscitation were significantly higher than those in the rat RBC group, but the levels at 24 h were similar in both groups. The expression of iNOS and ICAM-1, second messengers of inflammation, was not affected, and inflammatory levels after 24 h with HbVs are similar to rat RBC transfusion. The rat RBC group did not show an expected inflammatory reaction related to a transfusion-induced lung injury, and a clinical relevance concerning this level of transient inflammatory reaction induced by HbVs is not known; however, attention to the early stage of resuscitation in ongoing studies of HbV is required.