Restoring discarded porcine lungs by ex vivo removal of neutrophil extracellular traps.

BACKGROUND: By causing inflammation and tissue damage, neutrophil extracellular traps (NETs) constitute an underlying mechanism of aspiration-induced lung injury, a major factor of the low utilization of donor lungs in lung transplantation (LTx). METHODS: To determine whether NET removal during ex vivo lung perfusion (EVLP) can restore lung function and morphology in aspiration-damaged lungs, gastric aspiration lung injury was induced in 12 pigs. After confirmation of acute respiratory distress syndrome, the lungs were explanted and assigned to NET removal connected to EVLP (treated) (n = 6) or EVLP only (nontreated) (n = 6). Hemodynamic measurements were taken, and blood and tissue samples were collected to assess lung function, morphology, levels of cell-free DNA, extracellular histones, and nucleosomes as markers of NETs, as well as cytokine levels. RESULTS: After EVLP and NET removal in porcine lungs, PaO2/FiO2 ratios increased significantly compared to those undergoing EVLP alone (p = 0.0411). Treated lungs had lower cell-free DNA (p = 0.0260) and lower levels of extracellular histones in EVLP perfusate (p= 0.0260) than nontreated lungs. According to histopathology, treated lungs showed less immune cell infiltration and less edema compared with nontreated lungs, which was reflected in decreased levels of proinflammatory cytokines in EVLP perfusate and bronchoalveolar lavage fluid. CONCLUSIONS: To conclude, removing NETs during EVLP improved lung function and morphology in aspiration-damaged donor lungs. The ability to remove NETs during EVLP could represent a new therapeutic approach for LTx and potentially expand the donor pool for transplantation.

A pilot study of mechanical chest compressions with the LUCAS™ device in cardiopulmonary resuscitation.

AIM: The LUCAS™ device has been shown to improve organ perfusion during cardiac arrest in experimental studies. In this pilot study the aim was to compare short-term survival between cardiopulmonary resuscitation (CPR) performed with mechanical chest compressions using the LUCAS™ device and CPR performed with manual chest compressions. The intention was to use the results for power calculation in a larger randomised multicentre trial. METHODS: In a prospective pilot study, from February 1, 2005, to April 1, 2007, 149 patients with out-of hospital cardiac arrest in two Swedish cities were randomised to mechanical chest compressions or standard CPR with manual chest compressions. RESULTS: After exclusion, the LUCAS and the manual groups contained 75 and 73 patients, respectively. In the LUCAS and manual groups, spontaneous circulation with a palpable pulse returned in 30 and 23 patients (p = 0.30), spontaneous circulation with blood pressure above 80/50 mm Hg remained for at least 5 min in 23 and 19 patients (p = 0.59), the number of patients hospitalised alive >4h were 18 and 15 (p = 0.69), and the number discharged, alive 6 and 7 (p = 0.78), respectively. CONCLUSIONS: In this pilot study of out-of-hospital cardiac arrest patients we found no difference in early survival between CPR performed with mechanical chest compression with the LUCAS™ device and CPR with manual chest compressions. Data have been used for power calculation in a forthcoming multicentre trial.

Assessment of intravascular volume by transthoracic echocardiography during therapeutic hypothermia and rewarming in cardiac arrest survivors.

AIM: To study haemodynamic effects and changes in intravascular volume during hypothermia treatment, induced by ice-cold fluids and maintained by ice-packs followed by rewarming in patients after resuscitation from cardiac arrest. MATERIALS AND METHODS: In 24 patients following successful restoration of spontaneous circulation (ROSC), hypothermia was induced with infusion of 4 degrees C normal saline and maintained with ice-packs for 26 h after ROSC. This was followed by passive rewarming. Transthoracic echocardiography was performed at 12, 24 and 48 h after ROSC to evaluate ejection fraction and intravascular volume status. Central venous pressure (CVP), central venous oxygen saturation (ScvO(2)) and serum lactate were measured. Fluid balance was calculated. RESULTS: Twelve hours after ROSC, two separate raters independently estimated that 10 and 13 out of 23 patients had a decreased intravascular volume using transthoracic echocardiography. After 24 and 48 h this number had increased further to 14 and 13 out of 19 patients and 13 and 12 out of 21 patients. Calculated fluid balance was positive (4000 ml the day 1 and 2500 ml day 2). There was no difference in ejection fraction between the recording time points. Serum lactate and ScvO(2) were in the normal range when echocardiography exams were performed. CVP did not alter over time. CONCLUSIONS: Our results support the hypothesis that inducing hypothermia following cardiac arrest, using cold intravenous fluid infusion does not cause serious haemodynamic side effects. Serial transthoracic echocardiographic estimation of intravascular volume suggests that many patients are hypovolaemic during therapeutic hypothermia and rewarming in spite of a positive fluid balance.

No difference in autopsy detected injuries in cardiac arrest patients treated with manual chest compressions compared with mechanical compressions with the LUCAS device--a pilot study.

AIM: To compare the variety and incidence of internal injuries after manual and mechanical chest compressions during CPR. METHODS: In a prospective pilot study conducted in two Swedish cities, 85 patients underwent autopsy after unsuccessful resuscitation attempts with manual or mechanical chest compressions, the latter with the LUCAS device. Autopsy was performed and the results were evaluated according to a specified protocol. RESULTS: No injuries were found in 26/47 patients in the manual group and in 16/38 patients in the LUCAS group (p=0.28). Sternal fracture was present in 10/47 in the manual group and 11/38 in the LUCAS group (p=0.46), and there were multiple rib fractures (> or =3 fractures) in 13/47 in the manual group and in 17/38 in the LUCAS group (p=0.12). Bleeding in the ventral mediastinum was noted in 2/47 and 3/38 in the manual and LUCAS groups respectively (p=0.65), retrosternal bleeding in 1/47 and 3/38 (p=0.32), epicardial bleeding in 1/47 and 4/38 (p=0.17), and haemopericardium in 4/47 and 3/38 (p=1.0) respectively. One patient in the LUCAS group had a small rift in the liver and one patient in the manual group had a rift in the spleen. These injuries were not considered to have contributed to the patient's death. CONCLUSION: Mechanical chest compressions with the LUCAS device appear to be associated with the same variety and incidence of injuries as manual chest compressions.