Activities of an ECMO Center for Severe Respiratory Failure: ECMO Retrieval and Beyond, A 4-Year Experience.

OBJECTIVE: Beyond retrieval and management of patients with severe acute respiratory distress syndrome, an extracorporeal membrane oxygenation (ECMO) center also encompasses several other actions, such as on-call consultations, advice, and counseling, to the physicians at the peripheral centers, but few data are available on this topic. Therefore, the authors describe the composite activities of retrieval and counseling of an ECMO center since 2014. DESIGN: The referral calls addressed to the authors' ECMO center for patients with respiratory failure were prospectively recorded in a dedicated database. Referral call frequency, patient data, and results of the calls were analyzed. SETTING: The 12-bed intensive care unit of Careggi Hospital in Florence, the ECMO referral center for Tuscany, and the center of Italy, with a mobile ECMO team. PARTICIPANTS: Patients from intensive care units of peripheral hospitals for whom a referral call was addressed to the authors' ECMO center. INTERVENTIONS: Many possible responses were given after a referral call, varying from ECMO team deployment to advice or to refusal. MEASUREMENTS AND MAIN RESULTS: From January 1, 2014, to December 31, 2017, 231 calls were received at the authors' ECMO center, of which 220 calls were for acute respiratory failure cases. Throughout the study period the overall number of calls did not vary, but the percentage of ECMO retrievals decreased, whereas the percentage of ARF patients from peripheral hospital admitted to our ECMO center on conventional ventilation increased. Fifty-five patients were treated by the mobile ECMO team and were transferred on ECMO; 59 were admitted on ventilatory support. In flu periods the overall calls were more frequent than in the no-flu periods (171 v 82 calls), and more ECMO retrieval missions were deployed. CONCLUSIONS: During the study period, a decreased number of patients retrieved on ECMO was observed, whereas patients transferred on ventilation increased, with an overall unchanged number of referred patients.

Extracorporeal membrane oxygenation support for life-threatening acute severe status asthmaticus.

INTRODUCTION: Status asthmaticus is a life-threatening condition characterized by progressive respiratory failure due to asthma that is unresponsive to standard therapeutic measures. We used extracorporeal membrane oxygenation (ECMO) to treat patients with near-fatal status asthamticus who did not respond to aggressive medical therapies and mechanical ventilation under controlled permissive hypercapnia. MATERIALS AND METHODS: Between January 2011 and October 2015, we treated 16 adult patients with status asthmaticus (8 women, 8 men, mean age: 50.5±10.6years) with veno-venous ECMO (13 patients) or veno-arterial (3 patients). Patients failed to respond to conventional therapies despite receiving the most aggressive therapies, including maximal medical treatments, mechanical ventilation under controlled permissive hypercapnia and general anesthetics. RESULTS: Mean time spent on ECMO was 300±11.8 hours (range 36-384 hours). PaO2, PaCO2 and pH showed significant improvement promptly after ECMO initiation p=0.014, 0.001 and <0.001, respectively, and such values remained significantly improved after ECMO, p=0.004 and 0.001 and <0.001, respectively. The mean time of ventilation after decannulation until extubation was 175±145.66 hours and the median time to intensive care unit discharge after decannulation was 234±110.30 hours. All 16 patients survived without neurological sequelae. CONCLUSIONS: ECMO could provide adjunctive pulmonary support for intubated asthmatic patients who remain severely acidotic and hypercarbic despite aggressive conventional therapy. ECMO should be considered as an early treatment in patients with status asthmaticus whose gas exchange cannot be satisfactorily maintained by conventional therapy for providing adequate gas change and preventing lung injury from the ventilation.

Cellular cardiomyoplasty into infracted swine's hearts by retrograde infusion through the venous coronary sinus: An experimental study.

OBJECTIVES: The aim was to create a model of myocardial infarction with a borderline myocardial impairment which would enable evaluation of the retrograde cellular cardiomyoplasty through the venous coronary sinus in a large animal model. MATERIALS AND METHODS: Fifteen (study group) and 10 juvenile farm pigs (control group) underwent distal left anterior descending artery ligation. One month later the study group animals underwent sternotomy and a murine myoblastic line C2-C12 was injected at a constant pressure of 30mmHg, into the coronary sinus. Thirty days later all animals that survived from both groups underwent transthoracic echocardiography and 99Tc scintigraphy and were later euthanized and specimens were taken for microscopic evaluation. RESULTS: Cardiac output decreased significantly after ligation (p<0.001) and increased significantly after cardiomyoplasty (p<0.001). In all animals, the surgical induction of myocardial infarction caused a marked decline in the echocardiographic values of cardiac function; however, the cardiac function and dimensions were significantly improved in the study group after cardiomyoplasty versus the control group. All animals undergoing cardiomyoplasty demonstrated a significant reduction of the perfusion deficit in the left anterior descending artery territory, instead such data remained unchanged in the control group. The histological examination demonstrated the engrafted myoblasts could be distinguished from the activated fibroblasts in the scar tissue because they never showed any signs of collagen secretion and fiber buildup. CONCLUSIONS: In conclusion, the venous retrograde delivery route through the coronary sinus is safe and effective, providing a significant improvement in function and viability.

A numerical model of blood oxygenation during veno-venous ECMO: analysis of the interplay between blood oxygenation and its delivery parameters.

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an important tool in the management of most severe forms of acute respiratory failure. The determinants and management of oxygen delivery in patients treated with VV-ECMO is a complex topic. The physiological principles of oxygenation on VV-ECMO are reviewed in many textbooks. However a numerical model is an additional instrument to be used in understanding and exploring this intricate subject matter. We present a numerical model of blood oxygenation during VV-ECMO. Using this model we examined the role and impact of each determinant on blood oxygenation. The numerical analysis of variation and interplay between each oxygenation determinants during VV-ECMO is presented in graphical form. These results corroborate all the findings of previous studies. The proposed numerical model facilitates understanding of oxygenation physiology during VV-ECMO; it can be used for a medical simulation system and for teaching the principles of oxygenation during VV-ECMO.

A new formula for determining arterial oxygen saturation during venovenous extracorporeal oxygenation.

PURPOSE: Venovenous extracorporeal membrane oxygenation (VV-ECMO) is used to treat severe forms of acute respiratory distress syndrome (ARDS). VV-ECMO management may be confusing due to the lack of information about the interplay between the determinant parameters and their impact on oxygenation. We found a relationship between arterial oxygen saturation (SaO(2)) and its relevant parameters. The aim of this study was to assess the validity of this model. METHODS: We report our experience in 17 patients under VV-ECMO for severe ARDS. We compared, at two different levels of pump flow, SaO(2) and the oxygen saturation measured in the pulmonary artery (SpaO(2)) with the predicted saturation using the formula: SpaO(2) = (EF/CO)SmO(2) + (1 - EF/CO)SvO(2) + 10(-2)PmO(2), where PF is pump flow, R is recirculation, EF is effective flow [= (1 - R)PF], SmO(2) is saturation of the oxygenator outgoing blood, CO is cardiac output, SvO(2) is saturation of mixed venous blood, and PmO(2) is oxygen partial pressure of the oxygenator outgoing blood. RESULTS: There was no significant difference between predicted and measured SpaO(2): the mean predicted and measured SpaO(2) values were 90.7 ± 2.8 % and 90.4 ± 2.7 % , respectively (p = 0.696, r = 0.966). Bland-Altman analysis showed good agreement between predicted and measured SpaO(2). Predicted SpaO(2) and SaO(2) was well correlated (r = 0.80). CONCLUSIONS: We have presented an explicit relationship between SaO(2) and its direct determinants during VV-ECMO. Good agreement was found with the measured values of SaO(2), but the model remains to be fully validated before its use in clinical practice.

Atypical clinic presentation of pandemic influenza A successfully rescued by extracorporeal membrane oxygenation - Our experience and review of the literature.

The novel pandemic influenza A (H1N1) caused an epidemic of critical illness, and some patients developed severe acute respiratory distress syndrome (ARDS) or severe cardiopulmonary failure despite the use of conventional management. Extracorporeal membrane oxygenation (ECMO) support may successfully rescue these severely ill patients. We demonstrate the causative role of H1N1 in refractory ARDS of a previously healthy 15-year-old man who presented to the intensive care unit with a hypoxic and persistent cardiogenic shock refractory to conventional management as the leading symptom of influenza A. Because of compromised cardiopulmonary function, venovenous ECMO was applied 24 h after admission. Despite that the patient was manifesting heart failure, we decided the placement of venovenous ECMO because we believed that the real problem was the uncontrollable hypoxia and hypercapnia. A normal left ventricular ejection fraction was documented on a 2D echocardiography on day 2. The patient, after 6 days of ECMO, recovered completely and was successfully weaned from the mechanical ventilator on the 9th day after admission. The patient was discharged from the hospital on the 15th day. This experience showed that ECMO can be lifesaving for severe H1N1 infection also in patients with atypical clinical presentation of influenza.

Cellular retrograde cardiomyoplasty and relaxin therapy for postischemic myocardial repair in a rat model.

We sought to determine whether skeletal myoblasts, wild-type or engineered to express relaxin, might improve myocardial viability and performance in a rat model of chronic myocardial infarction. Our purpose was to investigate a potential new therapy for heart failure. From October 2005 through September 2009, we surgically induced acute myocardial infarction in 80 male Wistar rats. Thirty days after surgery, the rats underwent reoperation for the retrograde coronary venous infusion of skeletal myoblasts, relaxin, or both. The animals were randomly assigned to 4 experimental groups: R1 (the control group, which underwent saline-solution infusion), R2 (systemic relaxin therapy), R3 (myoblast infusion), and R4 (myoblast infusion and systemic relaxin therapy). Echocardiography, positron emission tomography, and cellular and histologic analysis were performed at 4 established time points. Mortality rates were similar among the groups. Postinfarction echocardiographic evaluation revealed similar left ventricular dysfunction. Viable myocardium, evaluated with positron emission tomography, was analogous. After therapy, the echocardiographic values of cardiac function improved significantly (P<0.05) in all groups except R1. Myocardial viability volume increased significantly in groups R3 and R4 (P<0.05) but was unchanged in groups R2 and R1. In group R4, the echocardiographic and positron emission tomographic results improved significantly (P<0.001). Histologic analysis showed that myoblasts settled in regions of ischemic scarring, especially when combined with relaxin. The retrograde venous route is safe, effective, and clinically feasible for cell delivery. Myoblasts and relaxin are better than either alone in terms of myocardial viability and performance improvement.

Extracorporeal membrane oxygenation for refractory, life-threatening, and herpes simplex virus 1-induced acute respiratory distress syndrome. Our experience and literature review.

We report our first experience of treating an immunocompetent adult patient with acute respiratory distress syndrome (ARDS) due to type 1 herpes simplex (HSV1) pneumonitis, using extracorporeal membrane oxygenation (ECMO). Similar cases reported in literature are reviewed as well. The therapeutic options for this particular complication are discussed. Pneumonia caused by HSV1 is a rare finding in immunocompetent individuals; it occurs more often in immunosuppressed and ventilated patients. It is a severe illness; therefore, early diagnosis and initiation of treatment are imperative. Diagnosis is based on cytologic and histologic findings, viral cultures, or serologic methods. This condition can be reversible; however, often, it can progress into refractory ARDS with limited therapeutic options available. We demonstrate the causative role of HSV1 in refractory ARDS of a previously healthy 18-year-old man who presented to the intensive care unit with acute respiratory distress after a week of flulike syndrome. Due to severe hypoxemia and hypercarbia, the patient required mechanical ventilation and later emergent blood oxygenation with extracorporeal support. For the first time in this condition, we used venovenous ECMO management, to rest the lung, sustain blood oxygenation and end-organ oxygen delivery, and promote potential lung recovery. During ECMO and after our etiologic diagnosis, specific therapy was introduced. After viral negativization, corticosteroid therapy (Meduri protocol) was initiated. Extracorporeal membrane oxygenation allowed us to initiate therapy while maintaining end-organ oxygenation and support the patient until lung recovery. After 18 days of ECMO, our patient recovered completely. Near-normal lung structures and functions were documented on a chest x-ray/computed tomography, thoracic ultrasonography, and pulmonary functional tests at hospital discharge and at a 1-year follow-up. Data suggest that severe pulmonary involvement in HVS1 infection associated with septicemia/shock is a rare but often fatal in immunocompetent adult as well. We suggest that ECMO might be the selected treatment for severe refractory ARDS in this clinical scenario. It seems to be an effective and useful ultimate therapeutic strategy for preventing death and furthermore permitting near-full pulmonary function recovery.