[Management and complications of venovenous extracorporeal membrane oxygenation]. / Conduite et complications de l'oxygénation extracorporelle veinoveineuse.

This article reviews the management of patients treated with venovenous extracorporeal membrane oxygenation (ECMO) for acute respiratory failure refractory to the conventional therapies. The period of extracorporeal respiratory support can be divided in three successive periods: the period of ECMO initiation, the period of treatment with ECMO, and the period of ECMO weaning. We will describe the main technical aspects of ECMO as well as the monitoring of the extracorporeal circuit and the ECMO-treated patient. The most frequent complications in each period of the management of ECMO-treated patients will be described and the possible adequate solutions will be considered.

Refractory hypercapnia: a simplified technique for extracorporeal CO2 removal (ECCO2R) in the presence of therapeutic limitations.

Refractory hypercapnia with severe acidosis appeared in a 67-year-old man who presented with lung fibrosis and a left pneumothorax as delayed complications of bleomycin chemotherapy for advanced grade lymphoma. Due to failure of noninvasive ventilation using a high-flow nasal cannula oxygen system, the patient was mechanically ventilated with two ventilators at different settings, after intubation with a double-lumen tube. As he had a poor haematological prognosis, extracorporeal membranous oxygenation was not considered. To remove some amount of carbon dioxide, we used a simplified method based on a veno-venous hemofiltration circuit coupled to a paediatric oxygenator and an air/oxygen blender. The efficacy on carbon dioxide removal was modest, with a percentage of CO2 total extraction ranging from 10.5 to 20.4%, but the system was immediately available, well tolerated and not very expensive.

Sensitivity, specificity, and surgical impact of somatosensory evoked potentials in descending aorta surgery.

BACKGROUND: We evaluate the efficiency of multilevel somatosensory evoked potential (SEP) monitoring for intraoperative re-establishment of blood flow to the spinal cord in 63 patients undergoing descending aorta repair. METHODS: The presence of critical vessels in a cross-clamped aortic segment was ascertained by a 15 minute SEP observation period while the segment between the clamps was vented to drain out the collateral flow. RESULTS: SEPs influenced the surgical strategy in 17 cases (27%): use of the Biomedicus in 1 traumatic rupture; critical vessel reimplantation or distal clamp replacement in 13 cases of segmental spinal ischemia; and hastening the procedure or proximal clamp replacement in 3 cases of left carotid ischemia. There were no cases of unexplained multilevel SEP abnormalities. Immediate paraplegia was observed in 2 cases (1 pre-existing; 1 forecast by a 199-minute period of SEP absence due to segmental ischemia); 2 patients presented delayed paraplegias despite unchanged intraoperative SEPs, and 1 case presented a transient paraplegia due to lower motoneuronal involvement. CONCLUSIONS: SEPs efficiently identified critical vessels to be reimplanted in order to avoid immediate paraplegia. However, systematic additional vessel reimplantation, if technically feasible, and prolongation of SEP monitoring during the postoperative period with careful blood pressure control are needed to prevent delayed paraplegia.

Randomized trial of intermittent antegrade warm blood versus cold crystalloid cardioplegia.

BACKGROUND: We performed a prospective randomized trial to compare intermittent antegrade warm blood cardioplegia with intermittent antegrade and retrograde cold crystalloid cardioplegia. METHODS: Two hundred consecutive patients scheduled for isolated coronary bypass surgical procedures were randomized into two groups: Group 1 (n = 92) received cold crystalloid cardioplegia with moderate systemic hypothermia, group 2 (n = 108) received intermittent antegrade warm blood cardioplegia with systemic normothermia. Preoperative, intraoperative, and postoperative data were prospectively collected. RESULTS: For the same median number of distal anastomoses, cardiopulmonary bypass duration and total ischemic arrest duration (57.3 +/- 20.5 versus 75 +/- 22.1 minutes, p < 0.001) were shorter in group 2 than in group 1. Apart from a higher right atrial pressure in the cold cardioplegia group, no hemodynamic difference was observed. Aspartate aminotransferase, creatine kinase-MB fraction, and cardiac troponin I levels were significantly lower in group 2 than in group 1. Outcome variables were not significantly different. CONCLUSIONS: Intermittent antegrade warm blood cardioplegia results in less myocardial cell damage than cold crystalloid cardioplegia, as assessed by the release of cardiac-specific markers. This beneficial effect has only marginal clinical consequences. Normothermic bypass has no deleterious effect on end-organ function.

Spontaneous pneumomediastinum and epidural pneumatosis after oral ecstasy consumption.

A 19-year-old man was admitted with acute dyspnoea. Physical examination revealed subcutaneous emphysema in the cervical and thoracic area. This was further confirmed by the total body computed tomography that also demonstrated mediastinal emphysema. Epidural pneumatosis of the thoracis spine was also evident. There was no history of trauma, but well of a recent oral ecstasy consumption during a techno rave party, associated with intense dancing and jumping. Clinical course was favourable with conservative therapy.

The Ca(2+) /calmodulin-dependent kinase kinase ß-AMP-activated protein kinase-α1 pathway regulates phosphorylation of cytoskeletal targets in thrombin-stimulated human platelets.

BACKGROUND: Platelet activation requires sweeping morphologic changes, supported by contraction and remodeling of the platelet actin cytoskeleton. In various other cell types, AMP-activated protein kinase (AMPK) controls the phosphorylation state of cytoskeletal targets. OBJECTIVE: To determine whether AMPK is activated during platelet aggregation and contributes to the control of cytoskeletal targets. RESULTS: We found that AMPK-α1 was mainly activated by thrombin, and not by other platelet agonists, in purified human platelets. Thrombin activated AMPK-α1 ex vivo via a Ca(2+) /calmodulin-dependent kinase kinase ß (CaMKKß)-dependent pathway. Pharmacologic inhibition of CaMKKß blocked thrombin-induced platelet aggregation and counteracted thrombin-induced phosphorylation of several cytoskeletal proteins, namely, regulatory myosin light chains (MLCs), cofilin, and vasodilator-stimulated phosphoprotein (VASP), three key elements involved in actin cytoskeletal contraction and polymerization. Platelets isolated from mice lacking AMPK-α1 showed reduced aggregation in response to thrombin, and this was associated with defects in MLC, cofilin and VASP phosphorylation and actin polymerization. More importantly, we show, for the first time, that the AMPK pathway is activated in platelets of patients undergoing major cardiac surgery, in a heparin-sensitive manner. CONCLUSION: AMPK-α1 is activated by thrombin in human platelets. It controls the phosphorylation of key cytoskeletal targets and actin cytoskeletal remodeling during platelet aggregation.

Effects of normothermia versus hypothermia on extravascular lung water and serum cytokines during cardiopulmonary bypass: a randomized, controlled trial.

OBJECTIVE: To evaluate the influence of perfusion temperature on the systemic effects of cardiopulmonary bypass (CPB), including extravascular lung water index (EVLWI), and serum cytokines. DESIGN: Prospective, randomized, controlled study. SETTING: Cardiothoracic intensive care unit of a university hospital. PATIENTS: Patients undergoing elective coronary artery bypass grafting. INTERVENTIONS: Twenty-one patients undergoing elective coronary artery bypass grafting were randomly assigned to receive either normothermic bypass (36 degrees C, n = 8) with intermittent antegrade warm blood cardioplegia (IAWBC), or hypothermic (32 degrees C, n = 13) CPB with cold crystalloid cardioplegia. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure, heart rate, cardiac output, systemic vascular resistance, mean pulmonary arterial pressure, and pulmonary vascular resistance were determined at baseline, i.e., after induction of anesthesia but before sternal opening (T-1), at arrival in the intensive care unit (T0), and 4 hrs (T4), 8 hrs (T8), and 24 hrs (T24) after surgery. EVLWI, intrathoracic blood volume index (ITBVI), and EVLW/ITBV ratio were obtained by using thermal dye dilution utilizing an arterial thermistor-tipped fiberoptic catheter and were recorded at T-1, T0, T4, T8, and T24. Serial blood samples for cytokine measurements were obtained at each hemodynamic measurement time point. Before, during, and after CPB, there were no differences in the conventional hemodynamic measurements between the groups. There were no changes in EVLWI up to T8 in either group. Furthermore, no change in the ratio EVLW/ITBW was observed between the groups at any time, further indicating the absence of a change in pulmonary permeability. Plasma levels of interleukin-6, tumor necrosis factor-alpha, and interleukin-10 increased during and after CPB, independently of the perfusion temperature. CONCLUSION: Normothermic CPB is not associated with additional inflammatory and related systemic adverse effects regarding cytokine production and EVLWI as compared with mild hypothermia. The potential temperature-dependent release of cytokines and subsequent inflammation has not been observed and normothermic CPB may be seen as a safe technique regarding this issue.