Hemodynamic response to pumpless extracorporeal membrane oxygenation

Respiratory support by means of arteriovenous extracorporeal membrane oxygenation driven by systemic arterial pressure, in contrast to pump-driven venoarterial extracorporeal membrane oxygenation, is attractive because of its simplicity and lack of trauma to formed blood elements. Although arteriovenous extracorporeal membrane oxygenation has been shown to improve arterial blood gases, useful levels of arteriovenous extracorporeal membrane oxygenation shunt flow may exert detrimental effects on systemic and pulmonary hemodynamics. Therefore the hemodynamic consequences of arteriovenous extracorporeal membrane oxygenation were studied in 11 dogs that were anesthetized, heparinized, and their lungs mechanically ventilated (FIO2 = 0.21) before and after induction of oleic acid pulmonary edema. The data indicate that arteriovenous extracorporeal membrane oxygenation shunt flows adequate to improve arterial blood gases resulted in significant changes in peripheral vascular resistance (-46%; p less than 0.05), systemic arterial blood pressure (-20%; p less than 0.05), and cardiac output (+110%; p less than 0.05). Dopamine infusion (5 micrograms/kg/min) proved to be more effective than volume expansion (15 ml/kg) in maintaining cardiac output, arterial blood pressure, and arterial blood gases. We conclude that pumpless arteriovenous extracorporeal membrane oxygenation, at flow rates adequate for respiratory support, can adversely alter systemic hemodynamics. However, these effects can be beneficially modulated by a moderate dose of inotropic medication.     

Plasma prostanoids in neonates with pulmonary hypertension treated with conventional therapy and with extracorporeal membrane oxygenation

Thromboxane may be a mediator of pulmonary hypertension in the neonate. Acute thromboxane-mediated pulmonary hypertension has been described in sheep receiving extracorporeal membrane oxygenation, which raises concerns about a potential thromboxane-mediated exacerbation of pulmonary hypertension in human neonates with severe pulmonary hypertension who are treated with extracorporeal membrane oxygenation. We measured plasma levels of thromboxane, prostaglandin F2 alpha, and 6-keto-prostaglandin F1 alpha in infants with pulmonary hypertension, some of whom were treated medically and some of whom were treated with extracorporeal membrane oxygenation. Plasma levels of all three prostanoids were elevated in infants with pulmonary hypertension and decreased with time, whether the neonates were treated with extracorporeal membrane oxygenation or with medical management alone. In infants treated with extracorporeal membrane oxygenation, we collected samples simultaneously from preoxygenator sites, postoxygenator sites, and umbilical artery catheter. We could demonstrate no significant difference in plasma prostanoid levels across the oxygenator. In two patients, plasma thromboxane and prostaglandin F2 alpha levels measured shortly after a platelet transfusion were distinctly higher in the umbilical artery catheter than in venous samples.     

Preoperative extracorporeal membrane oxygenation in newborns with total anomalous pulmonary venous connection.

This report describes three neonates who were supported with extracorporeal membrane oxygenation before surgical correction of total anomalous pulmonary venous connection. Extracorporeal membrane oxygenation was initially used to treat preoperative end-organ failure and suspected persistent pulmonary hypertension. All patients underwent surgical correction of total anomalous pulmonary venous connection after 8, 4 and 4 days of preoperative support, respectively. Two of these patients required extracorporeal membrane oxygenation after surgery; one died from bleeding while the other was weaned from extracorporeal membrane oxygenation on day 8 and discharged from the hospital. These results show that veno-arterial extracorporeal membrane oxygenation represents a life-saving perioperative means for supporting moribund neonates with total anomalous pulmonary venous connection and is effective in improving preoperative patient's condition.     

Plasma thromboxane and pulmonary artery pressure in neonates treated with extracorporeal membrane oxygenation.

To examine whether neonates with persistent pulmonary hypertension are subject to a thromboxane-mediated exacerbation of their pulmonary hypertension during extracorporeal membrane oxygenator therapy (a form of partial cardiopulmonary bypass), we performed serial measurements of plasma thromboxane B2 and pulmonary artery pressure before, during, and after extracorporeal membrane oxygenation. Pulmonary artery pressure was high before extracorporeal membrane oxygenation, did not increase after the start of this therapy, but began to decrease after 48 hours of extracorporeal membrane oxygenation. During the course of extracorporeal membrane oxygenation, mean pulmonary artery pressure decreased by 50% and mean plasma thromboxane B2 levels decreased by 70%. In addition, serial plasma thromboxane B2 levels were significantly correlated with pulmonary artery pressures in individual infants with a primary diagnosis of meconium aspiration (r = 0.965 to 0.723). We speculate that the decrease in pulmonary artery pressure and plasma thromboxane B2 levels over time may reflect resolution of acute lung injury and that thromboxane B2 may play a role in regulating pulmonary artery pressure in infants with meconium aspiration.     

Extracorporeal membrane oxygenation in children. New trends

At the Children's Hospital of Pittsburgh the extracorporeal membrane oxygenation program was started in 1980. The results of our experience from 1980 to 1985 were previously reported. In the past 2 years 39 additional newborn infants have been treated with this modality, with an overall survival rate of 79% (31/39). This survival rate is much better than that obtained in 33 neonates who had been treated in the previous 5 years (54%; p less than 0.05). A new aspect of our extracorporeal membrane oxygenation program is the use of total apneic lung rest for persisting pulmonary interstitial emphysema during support with the oxygenator. Six neonates were treated with this technique because of worsening pulmonary interstitial emphysema during extracorporeal circulation. Five of them survived. Another indication for extracorporeal membrane oxygenation in our pediatric population has been left ventricular or biventricular failure after cardiopulmonary bypass. Four of our seven patients treated for this indication are long-term survivors. At present, because of the impossibility of using other forms of left ventricular assist devices in the pediatric population, it seems that extracorporeal membrane oxygenation is the most effective treatment for left ventricular failure after cardiopulmonary bypass. From our experience, even in the absence of long-term follow-up of patients supported with extracorporeal membrane oxygenation, it appears that the benefits of this therapeutic modality far exceed the risks in the high-risk population for which it is being used.     

Selective use of extracorporeal membrane oxygenation is warranted after lung transplantation

OBJECTIVES: Early allograft dysfunction after lung transplantation ranges from subclinical x-ray abnormalities to pulmonary edema, hypoxemia, hypercarbia, and pulmonary hypertension. Management may include extracorporeal circulation to allow recovery of the acute lung injury. We reviewed our experience with extracorporeal membrane oxygenation after lung transplantation to assess the utility of this therapy. METHODS: A retrospective chart review was performed. Single or bilateral lung transplantation was performed in 444 adults from July 1988 to July 1998. Twelve (2.7%) patients experienced allograft dysfunction severe enough to require extracorporeal membrane oxygenation after failure of conventional therapy, including sedation, paralysis, and inhaled nitric oxide. RESULTS: Seven of 12 patients requiring extracorporeal membrane oxygenation were discharged from the hospital. Mean and median times to extracorporeal membrane oxygenation support were 1.2 days and 0 days, respectively. Mean length of support was 4.2 days. Four patients died while receiving extracorporeal membrane oxygenation support. One patient was weaned from extracorporeal membrane oxygenation but died during the hospitalization. Two patients required acute retransplantation while receiving extracorporeal membrane oxygenation, and one survived to discharge. Three patients continued to receive extracorporeal membrane oxygenation support for more than 4 days, and all 3 died. All survivors had begun receiving extracorporeal membrane oxygenation support by post-transplantation day 1. Three of 7 patients discharged from the hospital died 12 months, 13 months, and 72 months after transplantation because of bronchiolitis obliterans syndrome (n = 2) or lymphoma (n = 1). Four patients are alive 2, 12, 25, and 54 months after transplantation. CONCLUSIONS: Extracorporeal membrane oxygenation provides effective therapy for acute post-transplantation lung dysfunction. The frequency and pattern of our extracorporeal membrane oxygenation use reflects bias toward early extracorporeal membrane oxygenation support for isolated graft failure in otherwise intact and uninfected recipients.     

Combination of extracorporeal membrane oxygenation (ECMO) and pulmonary lavage in a patient with pulmonary alveolar proteinosis.

We describe a rare case of pulmonary alveolar proteinosis in a young woman with dyspnea and progressive hypoxaemia due to the alveolar deposition of insoluble, surfactant-like material. Routine treatment includes whole-lung-lavage (WLL) using double-lumen-tubes for selective lavaging of each lung. We performed three whole-lung-lavages and used veno-venous extracorporeal membrane oxygenation (v-vECMO) to support oxygenation during these procedures.     

Plasma prostanoids in neonatal extracorporeal membrane oxygenation. Influence of meconium aspiration

Thromboxane B2 may be a mediator of neonatal persistent pulmonary hypertension. Elevated levels of plasma thromboxane and prostacyclin have been described previously in hypoxic newborn infants with neonatal pulmonary hypertension. We measured serial plasma levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha (stable metabolite of prostacyclin) in 21 newborn infants with severe respiratory failure and pulmonary hypertension who required extracorporeal membrane oxygenation support. We sought to study (1) the evolution of plasma prostanoids in pulmonary hypertensive infants treated with extracorporeal membrane oxygenation and (2) whether different pulmonary hypertensive diagnostic subgroups have distinctive prostanoid profiles. Our data indicated that infants with meconium aspiration had significantly lower levels of plasma thromboxane B2 and 6-keto-prostaglandin F1 alpha while receiving extracorporeal membrane oxygenation than did infants with persistent pulmonary hypertension but no meconium aspiration. Levels of all infants decreased progressively as extracorporeal membrane oxygenation support continued.     

Extracorporeal membrane oxygenation in the treatment of neonatal respiratory failure

We report 18 consecutive neonates with severe respiratory failure due to pulmonary hypertension treated with extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation was begun at 52 +/- 36 hours of age with an arterial partial pressure of oxygen (PO2) of 36 +/- 14 mm Hg despite maximal pharmacologic and ventilator support (inspired fraction of oxygen [FiO2], 0.99 +/- 0.03; respiratory rate, 98 +/- 31/min; and positive inspiratory pressure, 54 +/- 11 cm of water). With initial flows of 130 +/- 17 mL/kg per minute, ventilator settings were reduced to the following: FiO2, 0.30; respiratory rates, 15/min; and positive inspiratory pressure, 24 cm of water. Support using extracorporeal membrane oxygenation was gradually reduced to 22% of initial flows and arterial blood samples showed pH 7.48 +/- .05, PO2 of 106 +/- 27 mm Hg, and PCO2 of 36 +/- 5 mm Hg just prior to decannulation. After 107 +/- 45 hours, extracorporeal membrane oxygenation was stopped and infants were extubated 61 +/- 53 hours (median, 46 hours) afterward. There was one death (94.4% survival rate); all survivors were discharged and underwent a follow-up examination at 1 to 27 months of age. Complications included two intracranial hemorrhages (one death and one asymptomatic), one patent ductus arteriosus requiring ligation on extracorporeal membrane oxygenation, and chronic lung disease in one patient. In selected neonates, extracorporeal membrane oxygenation allows for resolution of pulmonary hypertension, results in improved survival, and is associated with a low incidence of chronic lung disease. Extracorporeal membrane oxygenation should be considered in the treatment of severe respiratory failure.     

Venoarterial extracorporeal membrane oxygenation--how safe is it? Evaluation with a new experimental model.

This study was undertaken to find out if about 25% right cardiac output is sufficient for preservation of lung function during prolonged periods of venoarterial extracorporeal membrane oxygenation. Six healthy pigs weighing 57 kg were subjected to 18-hour venoarterial extracorporeal membrane oxygenation. During this period 1200 ml/min venous blood was delivered to the lungs through the pulmonary artery with the help of a separate roller pump and with use of the animal's own right ventricle to generate the pulse. Animals were observed for 6 hours after weaning from the venoarterial extracorporeal membrane oxygenation. At the sixth hour after extracorporeal membrane oxygenation, arterial oxygen tension, venous oxygen tension, lung compliance, and cardiac output had decreased significantly. Pulmonary vascular resistance and pulmonary clearance of technetium 99m-diethylenetriamine pentaacetic acid increased significantly also. The systemic arterial and venous carbon dioxide tensions, pH, and the base excess remained unchanged, as did the blood pressure and the systemic vascular resistance. Histopathology of the lung specimens revealed focal alveolar wall thickening and alveolar capillary congestion. The major portion of the pulmonary parenchyma looked normal. Alterations in pulmonary parameters cited were, to a major extent, explained on the basis of the experimental protocol followed and were believed to be reversible. This study suggests that about 25% of the systemic cardiac output should be diverted into the pulmonary artery for prevention of irreversible physiologic and histopathologic changes in the lungs during 18-hour normothermic venoarterial extracorporeal membrane oxygenation in healthy juvenile pigs.     

Successful treatment of peripartum massive pulmonary embolism with extracorporeal membrane oxygenation and catheter-directed pulmonary thrombolytic therapy

Chronic thromboembolic pulmonary hypertension during pregnancy is uncommon but is associated with maternal mortality in excess of 35%. We report a case of decompensated thromboembolic pulmonary hypertension requiring emergency caesarean section and postpartum treatment with extracorporeal membrane oxygenation and thrombolytic therapy with urokinase. The use of extracorporeal membrane oxygenation, catheter-directed pulmonary thrombolytic therapy and other pulmonary vasodilators for management of this life-threatening disease is discussed.     

Prolonged extracorporeal membrane oxygenation and circulatory support as bridge to lung transplant

A 38-year-old man with progressive alveolitis secondary to polymyositis was treated for 52 days with venovenous and venoarterial extracorporeal membrane oxygenation as a bridge to bilateral lung transplantation. The patient survived, despite multiple complications, and is now back home with good pulmonary function. He is working part-time nearly 3 years post-transplant. This case shows that long-term extracorporeal lung assist is a viable but demanding alternative for bridging patients to pulmonary transplantation. This case also shows that right ventricular failure necessating conversion to veno-arterial assist does not necessarily predict right ventricular failure post-transplant.     

Extracorporeal membrane oxygenation bridging to lung transplant complicated by heparin-induced thrombocytopenia

In patients with acute respiratory failure and life-threatening impairment of pulmonary gas exchange, venovenous extracorporeal membrane oxygenation offers further therapeutic options. During extracorporeal membrane oxygenation treatment, systemic anticoagulation is usually achieved by heparin administration, which exposes patients to the risk of heparin-induced thrombocytopenia type II. We present a patient with acute respiratory distress syndrome on venovenous extracorporeal membrane oxygenation who experienced heparin-induced thrombocytopenia type II and in whom anticoagulation was continued with argatroban. Because respiratory failure did not resolve, the patient was bridged to lung transplant with extracorporeal membrane oxygenation. Argatroban anticoagulation was safely used until lung transplant (on day 114 after extracorporeal membrane oxygenation initiation) and after transplant in the presence of hepatic failure.     

Massive pulmonary embolism after application of an Esmarch bandage

A 71-yr-old patient who underwent spinal anesthesia for left femoral fracture operation became hypotensive and unconscious after the application of an Esmarch bandage. The transesophageal echocardiography performed during resuscitation revealed pulmonary embolism and acute right ventricular failure. Pulmonary embolectomy with cardiopulmonary bypass was undertaken immediately after the echocardiographic diagnosis. Extracorporeal membrane oxygenation was used after the operation to support the failing right ventricle. The patient was successfully weaned from extracorporeal membrane oxygenation 10 days after the operation. We conclude that transesophageal echocardiography can be very useful in the immediate differential diagnosis of sudden cardiovascular collapse and that extracorporeal membrane oxygenation can be very helpful when acute right ventricular failure follows massive pulmonary embolism. IMPLICATIONS: Transesophageal echocardiography was highly valuable in finding the cause of sudden intraoperative cardiovascular collapse. The use of extracorporeal membrane oxygenation to support the failing right ventricle after emergent pulmonary embolectomy could help to rescue patients with massive pulmonary embolism.     

Late lung retransplantation using extracorporeal membrane oxygenation as a bridge: case report

Lung retransplantation is the only therapeutic option for acute and chronic graft failure, but only a few cases have been described to have been performed with extracorporeal membrane oxygenation (ECMO) support. We describe the successful case of a 46-year-old man treated with right lung transplantation and left lung retransplantation supported by venovenous ECMO.Lung retransplantation is the only therapeutic option to treat severe primary graft dysfunction, major technical problems, and refractory chronic rejection following pulmonary transplantation. Despite a number of comprehensive studies on lung retransplantation, only a few works have addressed the use of extracorporeal membrane oxygenation (ECMO) as a bridge to the surgical reoperation. ^{[1], [2], [3] and [4]} Herein we have presented a patient treated with pulmonary bilateral retransplantation subsequent to ECMO therapy for progressive deterioration of pulmonary function in single lung transplantation.     

Venovenous extracorporeal membrane oxygenation for cyanotic congenital heart disease

Background

Severe, refractory hypoxemia complicating uncorrected cyanotic congenital heart disease is a potentially lethal condition, even when urgent surgical intervention is undertaken. When a viral pneumonia initiates hypoxemia, the likelihood of a satisfactory outcome is further reduced. We examined our policy of venovenous extracorporeal membrane oxygenation support through the hypoxic event and performing delayed surgery, if required, to separate from extracorporeal membrane oxygenation.

Methods

A single institution, retrospective review of an Institutional Review Board approved database was undertaken. Over a 6-year period, 18 instances were identified for 17 patients who became acutely hypoxemic from either inadequate pulmonary blood flow (8 instances) or a viral pneumonia (10 instances) complicating their cyanotic heart disease. Demographics, duration of venovenous extracorporeal membrane oxygenation and outcomes are reported.

Results

The length of venovenous extracorporeal membrane oxygenation ranged from 13.5 to 362.5 hours (mean 130 ± 121 hours). During 10 supports, operations were performed to facilitate weaning from support. In 7 patients, extracorporeal support was weaned during this surgery. Follow-up was obtained in all patients over a period ranging from 4 months to 7 years (mean 39.0 ± 23.0 months). There were two late deaths due to sepsis 1.4 and 2.5 months after extracorporeal support.

Conclusions

Venovenous extracorporeal membrane oxygenation allows time for the recovery of acute hypoxic insult and resolution of some viral pneumonia processes. Palliative surgical procedures may be safely undertaken during extracorporeal support. Viral pneumonia is a risk for prolonged support. Venovenous extracorporeal membrane oxygenation is useful in these high-risk patients.     

Arteriovenous ECMO for neonatal respiratory support. A study in perigestational lambs.

A study was undertaken to investigate the applicability of the arteriovenous mode of perfusion for partial support of neonatal respiration. Perigestational lambs, delivered by cesarean section, served as the animal model of respiratory distress. Arteriovenous flow was accomplished between a single umbilical artery and vein. A microchannel membrane oxygenator was used to provide partial respiratory support to the newborn lambs. Total systemic flow, pulmonary blood flow, and pulmonary vascular resistance were assessed at various rates of arteriovenous perfusion and correlated with systemic oxygenation. A reduction in right-to-left shunting of blood and pulmonary vascular resistance occurred as arterial oxygenation rose from conditions of hypoxemia to PaO2 values higher than 50 torr. Myocardial performance was not impaired at rates of arteriovenous perfusion below 30 percent of the total systemic flow, as evidenced by normal electrocardiographic tracings, pulmonary capillary wedge pressures, and central venous pressures. Arteriovenous extracorporeal membrane oxgenation (ECMO) may be particularly suitable for use in infants with hypoxia and high pulmonary vascular resistance.     

Conduta em obstrução por coágulo em cânula de duplo lúmen bicaval após diagnóstico guiado por ETE: relato de caso

BackgroundVeno‐venous extracorporeal membrane oxygenation is an established therapy for patients with refractory acute respiratory distress syndrome (ARDS). One complication related to the use of veno‐venous extracorporeal membrane oxygenation is thrombosis despite proper anticoagulation. We report the diagnosis and management of a clot‐obstruction in a single site cannula placed through the internal jugular vein, guided by transesophageal echocardiography.Case reportA 39 year‐old male developed acute respiratory distress syndrome and hemodynamic instability after an episode of pulmonary aspiration in the ICU. Eight hours after placement of a single site veno‐venous extracorporeal membrane oxygenation, suddenly the perfusionist noticed a reduction in flow. TEE showed a thrombus‐like mass obstructing the inflow port in SVC and inflow at IVC was intact. After unsuccessful attempts to reposition the cannula, the team decided to insert additional femoral inflow cannula through the IVC. The single site catheter was then pulled out until its tip was positioned in the right atrium and all three ports of the catheter were switched to the infusion ports. After this, flows and oxygenation improved significantly. Unfortunately, despite all of the efforts, the patient died 2 days later.DiscussionThe diagnosis of veno‐venous extracorporeal membrane oxygenation cannula obstruction is based on reduced inflow rates, hemodynamic instability and poor oxygenation of blood. TEE allows evaluation of the flows inside the cannula and in this case, an obstruction was found. The management presented points to the fact that in a situation of catheter obstruction caused by a clot, there is a feasible alternative to assure minimal interruption of the hemodynamic support offered by the veno‐venous extracorporeal membrane oxygenation.     

Extracorporeal carbon dioxyde removal for additional pulmonary resection after pneumonectomy

Additional pulmonary surgery in a previously pneumonectomized patient requires apnea during surgical manipulation of the surviving lung. We report on a novel approach to manage the intraoperative apnea period, combining apneic oxygenation and minimally invasive, low flow extracorporeal CO2 removal. A 69-year-old man previously submitted to left pneumonectomy was scheduled for wedge resection of a single right upper lobe lesion. During the intraoperative apnea period, oxygenation was maintained through apneic oxygenation with continuous positive airway pressure (CPAP) of 5 cmH2O and inspiratory oxygen fraction (FiO2) of 1 and respiratory acidosis was prevented through extracorporeal CO2 removal, performed with the Decap? system (Hemodec, Salerno, Italy), a veno?venous pump-driven extracorporeal circuit including a neonatal membrane lung. The extracorporeal circuit was connected to the right femoral vein, accessed via a 14 Fr double lumen catheter. The blood flow through the circuit was 350 mL/min and the sweep flow of oxygen through the membrane lung was 8 L/min. The intraoperative apnea period lasted 13 minutes. Our approach allowed maintaining normocapnia (PaCO2 38,5 and 40 mmHg before and at the end of the apnea period, respectively), preserving oxygenation (P/F ratio 378, 191, 198 and 200 after 3, 6, 9 and 12 min of apnea, respectively). Our report suggests that the minimally invasive CO2 removal associated with apneic oxygenation is an useful technique for managing anesthesiological situations requiring moderate apnea periods.     

Extracorporeal membrane oxygenation with danaparoid sodium after massive pulmonary embolism

During extracorporeal membrane oxygenation, anticoagulation therapy is usually achieved with unfractionated heparin. We report on an extracorporeal membrane oxygenation with danaparoid sodium for a patient with severe respiratory failure due to massive pulmonary embolism and suspected type 2 heparin-induced thrombocytopenia. Danaparoid, a low molecular weight heparinoid, is an alternative to heparin for patients who develop type 2 heparin-induced thrombocytopenia. Danaparoid was given at 400 IU/h with an objective of antifactor Xa activity of 0.6-0.8 U/mL, which was monitored twice a day. No excessive bleeding or clotting of the circuit was noted. The patient was weaned from extracorporeal membrane oxygenation after 9 days of treatment.