Your activity: 4 p.v.

Extracorporeal membrane oxygenation (ECMO) in adults

Extracorporeal membrane oxygenation (ECMO) in adults
Author:
Scott Manaker, MD, PhD
Section Editor:
Polly E Parsons, MD
Deputy Editor:
Geraldine Finlay, MD
Literature review current through: Nov 2022. | This topic last updated: Oct 28, 2022.

INTRODUCTION — Mechanical cardiopulmonary support is most often applied intraoperatively to facilitate cardiac surgery (ie, cardiopulmonary bypass). However, cardiopulmonary support can also be delivered in a more prolonged fashion in an intensive care unit, although it is less common.

Prolonged cardiopulmonary support is called extracorporeal membrane oxygenation (ECMO), extracorporeal life support, or extracorporeal lung assist. There are two types of ECMO – venoarterial (VA) and venovenous (VV). Both provide respiratory support, but only VA ECMO provides hemodynamic support.

The impact of ECMO on clinical outcomes as well as patient selection, technical aspects, and complications will be reviewed here. Only adult applications are discussed. Extensive information about indications, complications, and outcome is available from the web site of the Extracorporeal Life Support Organization as well as guidelines from the 2020 EACT/ELSO/STS/AATS expert consensus panel [1,2].

OUTCOMES

Survival — The survival of patients undergoing ECMO can be categorized according to the indication for the ECMO: severe acute respiratory failure or cardiac failure.

Acute respiratory failure — Multiple studies have evaluated the effect of ECMO on mortality in patients with severe acute respiratory failure [3-16]. Several observational studies and uncontrolled clinical trials of patients with severe acute respiratory failure reported survival rates from 50 to 71 percent among patients who received ECMO compared with historical control rates [3-11,15-17]. After two poorly designed randomized trials of ECMO in the 1970s, two major randomized trials and one matched paired propensity analysis have shown benefit to early transfer to an ECMO center in patients with severe acute respiratory distress syndrome (ARDS) [11,12,18]. However, studies have been hampered by heterogeneous ventilation strategies in the conventional treatment arm and significant cross over from conventional therapies to ECMO. On balance, we believe that ECMO benefits those who fail to respond to conventional care (eg, PaO2/FiO2 consistently less than 70 mmHg) and that ECMO should be used early in the course rather than as rescue therapy; thus, adult patients with severe acute respiratory failure should be referred to an ECMO center for consideration of ECMO early in the course of their disease (eg, within the first seven days). The potential benefit from ECMO should always be weighed against the risk of transfer. In experienced ECMO centers, approximately 25 percent of patients will improve and recover without ECMO, while 75 percent of patients will require ECMO. Among those who require ECMO, 60 to 70 percent will survive. Data to support this strategy include the following:

CESAR – The Conventional ventilatory support versus Extracorporeal membrane oxygenation for Severe Acute Respiratory failure (CESAR; 2009) trial randomly assigned 180 patients with severe acute respiratory failure to either be referred to a single ECMO center in the United Kingdom or undergo continued conventional management [12]. The group referred to the ECMO center had significantly increased survival without disability at six months compared to conventional management (63 versus 47 percent). Twenty five percent of the patients referred for ECMO were not managed with ECMO because five died before transfer to the ECMO center and 16 recovered with the conventional ventilation protocol used by the ECMO center. Of note, the trial defined severe acute respiratory failure as hypercapnic respiratory acidosis with an arterial pH <7.20 or a Murray score greater than 3.0. The Murray score quantitates the severity of lung disease on the basis of the ratio of arterial oxygen tension to the fraction of inspired oxygen (PaO2/FiO2), positive end-expiratory pressure (PEEP), lung compliance, and chest radiograph. Important exclusion criteria included an age <18 years or >65 years, intubation greater than seven days, and contraindications to anticoagulation. However, this trial was criticized for the heterogeneous ventilation strategies in the control group and the large number of patients transferred for ECMO that never received it due to improvement with standard low-volume ventilation. The conclusion of this trial was that adults with severe acute respiratory failure should be referred to an ECMO center for evaluation for ECMO.

EOLIA – The ECMO to rescue lung injury in severe ARDS (EOLIA; 2018) trial randomly assigned 249 patients with severe ARDS (partial arterial pressure of oxygen:fraction of inspired oxygen ratio [PaO2:FiO2] <50 mmHg >3 hours or PaO2:FiO2 <80 mmHg for >6 hours) to receive early (as soon as entry criteria are met) venovenous ECMO or conventional low-tidal volume low-pressure ventilation (which could include late ECMO as a rescue therapy) [18]. ECMO resulted in improved oxygenation, more days free of renal failure (46 versus 21 percent), and fewer patients with ischemic stroke (0 versus 5 percent). Although the study was stopped early by the data safety and monitoring board for interim results that were in favor of ECMO [19], after the final analysis, the 11 percent difference in actual 60-day mortality, while also in favor of early ECMO, was not significant (35 versus 46 percent). Although no formal subgroup analysis was performed, but in keeping with a possible benefit from early ECMO, survival was higher in those who received early (two days after onset; 65 percent) compared with late (six days after onset; ie, rescue) ECMO (43 percent). With regard to adverse effects, ECMO resulted in higher rates of bleeding requiring transfusion (46 versus 28 percent) and severe thrombocytopenia (27 versus 16 percent) compared with conventional therapy. These results may have been biased in favor of conventional care by several factors including early termination of the trial, the high percentage of sicker patients that crossed over from the conventional treatment group to the ECMO group for rescue therapy (28 percent; median PaO2 was 51 mmHg compared with 73 mmHg at study entry), and the high utilization in the control group of ARDS therapies associated with improved outcome or oxygenation including prone positioning (90 percent), inhaled pulmonary vasodilators (83 percent), and neuromuscular blockade (100 percent). In our opinion, this study supports the conclusion that patients with severe ARDS who fail to respond to optimal treatment (eg, low tidal volume ventilation with or without a short trial of prone ventilation, pulmonary vasodilators, and neuromuscular blockade) should be managed with ECMO promptly rather than later as a rescue treatment.  

Matched paired analyses – A study of 75 matched pairs of patients with severe influenza H1N1-related acute respiratory distress syndrome found that referral and transfer to an ECMO center was associated with lower hospital mortality (23.7 versus 52.5 percent) [11]. Eighty five percent of the patients referred to an ECMO center were managed with ECMO, while the others improved with conventional ventilation. In contrast, another study in the same population reported no difference when compared with conventional mechanical ventilation. [13].

Meta-analyses – One meta-analysis of two randomized trials [12,19] and three observational studies reported the 60-day mortality rate was lower in patients receiving venovenous ECMO (34 versus 47 percent; relative risk [RR] 0.73, 95% CI 0.58-0.92) [20]. Adverse events could not be pooled due to lack of reporting in control groups but was assessed at 19 percent and likely higher in those receiving ECMO compared with standard mechanical ventilation strategies. A network meta-analysis that compared several interventions in patients with moderate to severe ARDS on low tidal volume ventilation reported that ECMO was associated with a reduced 28-day mortality [21]. Another meta-analysis that combined data from CESAR and EOLIA reported a reduction in mortality at 90 days (RR 0.75 (95% CI 0.6–0.94) [22].

Other studies have shown value in those who need a bridge to transplantation. As an example, in a study of 21 patients with acute on chronic respiratory failure from interstitial lung disease, six were successfully bridged to lung transplant, five of whom were eventually discharged [23].

Cardiac failure — Venoarterial (VA) ECMO can provide acute support in cardiogenic shock or cardiac arrest in adults. Assuming that the brain function is normal or only minimally impaired, ECMO is provided until the patient recovers or receives a long-term ventricular assist device as a bridge to cardiac transplantation.

Observational studies and case series have reported survival rates of 20 to 50 percent among patients who received ECMO for cardiac arrest, severe cardiogenic shock, or failure to wean from cardiopulmonary bypass following cardiac surgery and including older adults [24-36].

In two observational studies, ECMO performed for cardiac arrest was associated with increased survival compared to conventional cardiopulmonary resuscitation [37,38].

Long-term survivors of ECMO performed for cardiogenic shock have better general health, physical health, and social functioning than patients who require chronic hemodialysis, have advanced heart failure, or have recovered from ARDS [28].

In another study of patients with acute cardiopulmonary failure, the overall mortality was 60 percent at one month and 76 percent at one year; mortality worsened if ECMO was required for more than three days [32]. Unlike ECMO for respiratory failure, there will never be a controlled trial of ECMO for cardiac failure because assignment to a control group is not justified.

In an extracorporeal life support organization registry, among 9000 adults who underwent ECMO, 41 percent survived to hospital discharge with the lowest survival reported in those with congenital heart disease (37 percent) [33].

In a systematic review of adults with refractory out of hospital cardiac arrest, survival was 22 percent in the 833 patients who received ECMO during resuscitation and half of these had good neurological recovery [39]. In addition, 17 organ donors were identified in the nonsurvivor population. Registry data showed a similar survival of 29 percent among 2885 adults supported with ECMO during CPR [33].  

PATIENT SELECTION

Indications — Guidelines that describe the indications and practice of ECMO are published by the Extracorporeal Life Support Organization (ELSO) [40,41]. Criteria for the initiation of ECMO include acute severe cardiac or pulmonary failure that is potentially reversible and unresponsive to conventional management. Examples of clinical situations that may prompt the initiation of ECMO include the following:

Hypoxemic respiratory failure with a ratio of arterial oxygen tension to fraction of inspired oxygen (PaO2/FiO2) of <100 mmHg despite optimization of the ventilator settings, including the tidal volume, positive end-expiratory pressure (PEEP), and inspiratory to expiratory (I:E) ratio. The Berlin consensus document on acute respiratory distress syndrome (ARDS) suggests ECMO in severe respiratory failure (PaO2/FiO2 <70) [42].

Hypercapnic respiratory failure with an arterial pH less than 7.20 [43].

Ventilatory support as a bridge to lung transplantation.

Cardiac/circulatory failure/refractory cardiogenic shock including right ventricular failure [44,45].

Massive pulmonary embolism.

Cardiac arrest [44,46].

Failure to wean from cardiopulmonary bypass after cardiac surgery.

As a bridge to either cardiac or lung transplantation or placement of a ventricular assist device [47].

Pregnancy does not appear to be a contraindication to ECMO, which has been used successfully as a salvage therapy during pregnancy and the post-partum period [48].

Relative contraindications — The only absolute contraindication to ECMO is a pre-existing condition that is incompatible with recovery (severe neurologic injury, end stage malignancy). Relative contraindications include uncontrollable bleeding and very poor prognosis from the primary condition. Results in respiratory failure are better when ECMO is instituted within seven days of intubation.

TECHNIQUE — ECMO is being increasingly used [49]. ECMO should only be performed by clinicians with training and experience in its initiation, maintenance, and discontinuation.

During ECMO, blood is drained from the native vascular system, circulated outside the body by a mechanical pump, and reinfused into the circulation. While outside the body, the blood passes through an oxygenator and heat exchanger. In the oxygenator, hemoglobin becomes fully saturated with oxygen, while carbon dioxide (CO2) is removed. Oxygenation is determined by flow rate, whereas elimination of CO2 can be controlled by adjusting the rate of countercurrent gas flow through the oxygenator [50].

ECMO can be venovenous (VV) or venoarterial (VA):

During VV ECMO, blood is extracted from the vena cava or right atrium and returned to the right atrium (figure 1). VV ECMO provides respiratory support, but the patient is dependent upon his or her own hemodynamics.

During VA ECMO, blood is extracted from the right atrium and returned to the arterial system, bypassing the heart and lungs (figure 2 and figure 3). VA ECMO provides both respiratory and hemodynamic support. The additional benefit of hemodynamic support comes with additional risks, which are discussed below. (See 'VA ECMO-specific complications' below.)

Initiation — Once it has been decided that ECMO will be initiated, the patient is anticoagulated (usually with intravenous heparin) and then the cannulae are inserted. ECMO support is initiated once the cannulae are connected to the appropriate limbs of the ECMO circuit.

Cannulation — Cannulae are usually placed percutaneously by Seldinger technique. The largest cannulae that can be placed in the vessels are used.

For VV ECMO, venous cannulae are usually placed in the right or left common femoral vein (for drainage) and right internal jugular vein (for infusion). The tip of the femoral cannula should be maintained near the junction of the inferior vena cava and right atrium, while the tip of the internal jugular cannula should be maintained near the junction of the superior vena cava and right atrium. Alternatively, a double lumen cannula is available that is large enough to accommodate 4 to 5 L/min of blood flow [51]. It is available in a variety of sizes, with 31 French being the largest and most appropriate for adult males. The drainage and infusion ports have been engineered to minimize recirculation.

For VA ECMO, a venous cannula is placed in the inferior vena cava or right atrium (for drainage) and an arterial cannula is placed into the right femoral artery (for infusion).

Femoral access is preferred for VA ECMO because insertion is relatively easy. The main drawback of femoral access is ischemia of the ipsilateral lower extremity. The likelihood of this complication can be decreased by inserting an additional arterial cannula distal to the femoral artery cannula and redirecting a portion of the infused blood to the additional cannula for "reperfusion" of the extremity. Alternatively, a cannula can be inserted into the posterior tibial artery for retrograde flow to the extremity [52].

Occasionally, the femoral vessels are unsuitable for cannulation for VA ECMO (eg, patients with severe occlusive peripheral artery disease or prior femoral arterial reconstruction). In such circumstances, the right common carotid artery or subclavian artery can be used. In our experience, there is a 5 to 10 percent risk of a large watershed cerebral infarction when the right common carotid artery is used. Use of the subclavian artery offers the advantage of allowing patients on ECMO to ambulate [53].

For postcardiotomy ECMO, the cannulae employed for cardiopulmonary bypass can be transferred from the heart-lung machine to the ECMO circuit, with blood drained from the right atrium and reinfused into the ascending aorta.

Titration — Following cannulation, the patient is connected to the ECMO circuit and the blood flow is increased until respiratory and hemodynamic parameters are satisfactory. Reasonable targets include:

An arterial oxyhemoglobin saturation of >90 percent for VA ECMO, or >75 percent for VV ECMO

A venous oxyhemoglobin saturation 20 to 25 percent lower than the arterial saturation, measured on the venous line

Adequate tissue perfusion, as determined by the arterial blood pressure, venous oxygen saturation, and blood lactate level

Maintenance — Once the initial respiratory and hemodynamic goals have been achieved, the blood flow is maintained at that rate. Frequent assessment and adjustments are facilitated by continuous venous oximetry, which directly measures the oxyhemoglobin saturation of the blood in the venous limb of the ECMO circuit. When the venous oxyhemoglobin saturation is below target, interventions that may be helpful include increasing one or more of the following: blood flow, intravascular volume, or hemoglobin concentration. Decreasing the systemic oxygen uptake by reducing the temperature may also be helpful.

Anticoagulation is sustained during ECMO with a continuous infusion of unfractionated heparin or direct thrombin inhibitor titrated to an activated clotting time (ACT) of 180 to 210 seconds. The ACT target is decreased if bleeding develops. ACT is easily determined at the point of care, but plasma PTT (1.5 times normal) can also be used. Thromboelastography is a useful adjunct. When heparin is used, the anticoagulant effect is dependent on the amount of endogenous antithrombin (AT3). If AT3 deficiency is suspected, the level can be measured. If less than 50 percent normal, AT3 is replaced by fresh frozen plasma. Less commonly, some specialized centers follow anti-factor Xa levels. One review of 16 studies suggested that optimal targets vary among centers resulting in variable rates of bleeding and thromboembolism [54]. (See "Antithrombin deficiency".)

Platelets are continuously consumed during ECMO because they are activated by exposure to the foreign surface area. Platelet counts should be maintained greater than 50,000/microliter, which may require platelet transfusion.

The ECMO circuit is often the only source of oxygen in patients with complete cardiac or pulmonary failure. Oxygen delivery depends on the amount of hemoglobin and blood flow. The risks of high blood flow outweigh the risk of transfusion, so hemoglobin is maintained over 12 g/dL in ECMO patients [55].

Ventilator settings are reduced during ECMO in order to avoid barotrauma, volutrauma (ie, ventilator-induced lung injury), and oxygen toxicity. Plateau airway pressures should be maintained less than 20 cm H2O and FiO2 less than 0.5. Reduction of ventilator support is usually accompanied by increased venous return, which improves cardiac output.

We perform early tracheostomy to reduce dead space and improve patient comfort. Patients typically require light sedation during ECMO, although we prefer to maintain patients awake, extubated, and breathing spontaneously. (See "Tracheostomy: Rationale, indications, and contraindications".)

Special considerations — VV ECMO is typically used for respiratory failure, while VA ECMO is used for cardiac failure. There are unique considerations for each type of ECMO, which influence management.

Blood flow – Near-maximum flow rates are usually desired during VV ECMO to optimize oxygen delivery. In contrast, the flow rate used during VA ECMO must be high enough to provide adequate perfusion pressure and venous oxyhemoglobin saturation (measured on drainage blood), but low enough to provide sufficient preload to maintain left ventricular output.

Diuresis – Since most patients are fluid overloaded when ECMO is initiated, aggressive diuresis is warranted once the patient is stable on ECMO. Ultrafiltration can be easily added to the ECMO circuit if patients are unable to produce sufficient urine for diuresis.

Left ventricular monitoring – Left ventricular output must be rigorously monitored during VA ECMO because left ventricular output may worsen. The cause is usually multifactorial, including the underlying left ventricular dysfunction and insufficient unloading of the distended left ventricle due to ongoing blood flow to the left ventricle from the bronchial circulation and right ventricle. Left ventricular output can be closely monitored by identifying pulsatility in the arterial line's waveform and by frequent echocardiography. Interventions that can improve left ventricular output include inotropes (eg, dobutamine, milrinone) to increase contractility and intra-aortic balloon counterpulsation to reduce afterload and facilitate left ventricular output. Immediate left ventricular decompression is essential to avoid pulmonary hemorrhage if left ventricular ejection cannot be maintained despite intra-aortic balloon counterpulsation and inotropic agents. This can be accomplished surgically or percutaneously. Methods of percutaneous left ventricular decompression include transatrial balloon septostomy or insertion of a left atrial or ventricular drainage catheter.

Weaning from ECMO — For patients with respiratory failure, improvements in radiographic appearance, pulmonary compliance, and arterial oxyhemoglobin saturation indicate that the patient may be ready to be liberated from ECMO. For patients with cardiac failure, enhanced aortic pulsatility correlates with improved left ventricular output and indicates that the patient may be ready to be liberated from ECMO.

One or more trials of taking the patient off ECMO should be performed prior to discontinuing ECMO permanently:

VV ECMO trials are performed by eliminating all countercurrent sweep gas through the oxygenator. Extracorporeal blood flow remains constant, but gas transfer does not occur. Patients are observed for several hours, during which the ventilator settings that are necessary to maintain adequate oxygenation and ventilation off ECMO are determined.

VA ECMO trials require temporary clamping of both the drainage and infusion lines, while allowing the ECMO circuit to circulate through a bridge between the arterial and venous limbs. This prevents thrombosis of stagnant blood within the ECMO circuit. In addition, the arterial and venous lines should be flushed continuously with heparinized saline or intermittently with heparinized blood from the circuit. VA ECMO trials are generally shorter in duration than VV ECMO trials because of the higher risk of thrombus formation.

Once the decision has been made to discontinue ECMO, the cannulae are removed. Hemostasis is achieved by compressing the insertion site. For patients who received VA ECMO, at least thirty minutes of compression is required for the arterial site.

COMPLICATIONS — The major complications are bleeding and thromboembolism.

Bleeding — Bleeding occurs in 30 to 50 percent of patients who receive ECMO and can be life-threatening [54,56]. It is due to both the continuous anticoagulation and platelet dysfunction. Meticulous surgical technique, maintaining platelet counts greater than 50,000/mm3, and maintaining the target activated clotting time (ACT) reduce the likelihood of bleeding.

Intervention is necessary when major bleeding occurs. Bleeding from surgical wounds often requires prompt exploration with liberal use of electrocautery. Hemorrhage into body cavities (eg, abdomen, pleural space) may require surgical exploration to achieve hemostasis, after which vacuum-assisted closure is recommended because it allows removal and measurement of the blood. Plasminogen inhibitors (eg, aminocaproic acid) can be infused or heparin can be discontinued for several hours, but these actions may increase the risk of circuit thrombosis [57-59]. Infusion of activated factor VII has been reported with mixed results and should only be considered for life-threatening hemorrhage after all other options have failed [60,61].

The target ACT is usually reduced once bleeding occurs and infusions of anticoagulant are reduced or held. As an example, the target ACT may become 170 to 190 seconds, instead of 210 to 230 seconds. With modern devices the anticoagulation can be stopped altogether for days if bleeding is a problem. Recombinant factor VIIa has been administered to some cases of refractory bleeding [62].

Thromboembolism — Systemic thromboembolism due to thrombus formation within the extracorporeal circuit is a complication that can be devastating with one report suggesting rates of pulmonary embolism as high as 16 percent [54,63,64]; rates of deep venous thrombosis may be higher (up to 70 percent) and may be associated with cannulation, especially femorofemoral cannulae. Its impact is greater with venoarterial (VA) ECMO than venovenous (VV) ECMO because infusion is into the systemic circulation. Anticoagulation that achieves its target ACT and vigilant observation of the circuit for signs of clot formation successfully prevents thromboembolism in most patients.

Observation of the circuit for signs of clot formation includes routine inspection of all connectors and monitoring the pressure gradient across the oxygenator. A sudden change in the pressure gradient suggests that a thrombus had developed. Large or mobile clots require immediate circuit or component exchange. Primed circuits are usually kept at the bedside if the target ACT has been reduced due to bleeding because the risk of thrombus formation is greatest in this situation. Having a primed circuit available facilitates urgent exchange, if necessary.

Neurological — The incidence of neurologic injury in adult respiratory failure patients recorded in the Extracorporeal Life Support Organization (ELSO) registry and others is approximately 10 percent [65]. The incidence in cardiac failure and for those in whom ECMO is administered during cardiopulmonary resuscitation is 50 percent [10,66].

Cannulation-related — A variety of complications can occur during cannulation, including vessel perforation with hemorrhage, arterial dissection, distal ischemia, and incorrect location (eg, venous cannula within the artery). These complications are rare (<5 percent). A skilled and experienced surgeon is important to avoid or address such complications.

Heparin-induced thrombocytopenia — Heparin-induced thrombocytopenia (HIT) can occur in patients receiving ECMO. When HIT is proven, the heparin infusion should be replaced by a non-heparin anticoagulant [67]. We favor argatroban because its half-life is short and a similar ACT target range is effective. (See "Management of heparin-induced thrombocytopenia".)

VA ECMO-specific complications

Pulmonary hemorrhage – Pulmonary edema and hemorrhage can occur in patients who have no left ventricular (LV) emptying during VA ECMO. Edema occurs when the left atrial (LA) pressure exceeds 25 mmHg. It is treated by venting the LA or LV. (See 'Special considerations' above.)

Cardiac thrombosis – There is retrograde blood flow in the ascending aorta whenever the femoral artery and vein are used for VA ECMO. Stasis of the blood can occur if left ventricular output is not maintained, which may result in thrombosis.

Coronary or cerebral hypoxia – During VA ECMO, fully saturated blood infused into the femoral artery from the ECMO circuit will preferentially perfuse the lower extremities and the abdominal viscera. Blood ejected from the heart will selectively perfuse the heart, brain, and upper extremities. As a result, the oxyhemoglobin saturation of the blood perfusing the lower extremities and abdominal viscera may be substantially higher than that perfusing the heart, brain, and upper extremities. Cardiac and cerebral hypoxia could exist and be unrecognized if oxygenation is monitored using only blood from the lower extremity. To avoid this complication, arterial oxyhemoglobin saturation should be monitored in the right upper extremity. Poor arterial oxyhemoglobin saturation measured from the upper extremity is corrected by infusing some oxygenated blood into the right atrium (called VA-V access).

Neurological injury – In a report of neurologic injury in cardiac (VA) patients in one institution, 42 of 87 patients sustained neurologic injury (approximately 50 percent) [66]. The types of neurological injury included coma of uncertain cause (11 patients), encephalopathy (11 patients), anoxic brain injury (9 patients), stroke (7 patients), brain death (3 patients), and myoclonus (1 patient). It is important to realize that these findings may be a consequence of the condition that prompted ECMO, rather than a complication of the ECMO process. Another report suggested that low levels of hemolysis that can occur during VA-ECMO may predispose to nonhemorrhagic stroke [68].

Mental health issues — Studies among survivors of ECMO suggest a similar syndrome to post intensive care unit syndrome (PICS). This was best illustrated by a large retrospective Canadian study of 642 survivors of ECMO, the incidence of new mental health conditions was 22 per 100 person years compared with 14.5 per 100-person years in 3820 matched ICU survivors who did not receive ECMO [69]. These conditions mostly included mood disorders, anxiety, and post-traumatic stress disorder. There were no significant differences between the groups in substance misuse or self-harm. (See "Post-intensive care syndrome (PICS)".)

FUTURE — Applications for ECMO may expand in the future to include percutaneous temporary left ventricular assistance and low flow ECMO for CO2 removal (ECCO2R) [70]. In addition, new technologies will improve the simplicity and safety of ECMO, including new oxygenators, pumps, and surface coatings. The lack of benefit associated with ECCO2R combined with low tidal volume ventilation in patients with acute hypoxemic respiratory failure is discussed separately [71]. (See "Ventilator management strategies for adults with acute respiratory distress syndrome", section on 'Ventilator strategies of questionable benefit or harm'.)

Oxygenators that use hollow fibers constructed of polymethyl-pentene are routine and can be used for weeks [72-74]. Advantages compared with older devices include lower priming volume, rapid priming time, diminished plasma leakage, and low blood flow resistance, which may reduce platelet activation and consumption. One study reported that there are no differences among the newer oxygenators regarding the impact on hemostasis, anticoagulation, or hemolysis [75].

In the past, ECMO centers depended upon servoregulated (ie, automatic) roller pumps for blood flow generation, which required continuous observation by trained personnel. Centrifugal pumps without servoregulation have replaced roller pumps in most centers. The advantage is that the outlet pressure is limited, so "blow out" on the high pressure side is unlikely. However, these pumps can cause microcavitation and hemolysis when the inlet is occluded. Newer centrifugal pumps have special rotors that reduce heat generation and microcavitation [76,77]. These pumps are now widely used for ECMO.

Surface coatings that mimic the endothelial lining of blood vessels and reduce blood cell activation are being developed [78]. In an ECMO circuit, such coatings could reduce thrombogenicity, obviate the need for continuous anticoagulation, and reduce the incidence of related complications.

Ambulatory ECMO remains investigational [79].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Acute respiratory failure and acute respiratory distress syndrome in adults".)

SUMMARY AND RECOMMENDATIONS

Extracorporeal membrane oxygenation (ECMO) is a type of prolonged mechanical cardiopulmonary support that is usually delivered in the intensive care unit. ECMO should only be performed in centers with the appropriate equipment and expertise. (See 'Introduction' above.)

We suggest that patients with severe, but potentially reversible, acute respiratory or cardiac failure that is unresponsive to conventional management be evaluated for ECMO if it is available within the medical center (Grade 2B). For patients who are in a medical center that does not provide ECMO, transfer to another medical center to be evaluated for ECMO should be considered as soon as it is clear that the patient is not responding to management. The final decision should carefully weigh the survival rates for patients referred to an ECMO center versus the risk of transferring the patient. (See 'Indications' above.)

There are two types of ECMO, venovenous (VV) and venoarterial (VA) (figure 1 and figure 2 and figure 3). VV ECMO is used in patients with respiratory failure, while VA ECMO is used in patients with cardiac failure. (See 'Technique' above.)

Once it has been determined that ECMO will be initiated, the patient is anticoagulated. Cannulae are then inserted and the patient is connected to the ECMO circuit. The blood flow is increased until respiratory and hemodynamic parameters are satisfactory. Once the initial respiratory and hemodynamic goals have been achieved, blood flow is maintained, ventilator support is minimized, and vasoactive drugs are decreased to minimal levels. Frequent reassessment and adjustments are usually necessary. (See 'Initiation' above and 'Maintenance' above.)

The patient's readiness for weaning from ECMO should be evaluated frequently. Prior to discontinuing ECMO permanently, one or more trials should be performed during which the patient is off ECMO. Such trials give the clinician the opportunity to determine whether conventional supportive care is sufficient for the patient. (See 'Weaning from ECMO' above.)

Bleeding is the most common complication (30 to 40 percent) of ECMO. Thromboembolism and cannula complications are rare (<5 percent). (See 'Complications' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Jonathan Haft, MD, and Robert Bartlett, MD, who contributed to earlier versions of this topic review.

  1. The Registry of the Extracorporeal Life Support Organization. www.elso.org (Accessed on October 09, 2015).
  2. Lorusso R, Whitman G, Milojevic M, et al. 2020 EACTS/ELSO/STS/AATS expert consensus on post-cardiotomy extracorporeal life support in adult patients. J Thorac Cardiovasc Surg 2021; 161:1287.
  3. Hemmila MR, Rowe SA, Boules TN, et al. Extracorporeal life support for severe acute respiratory distress syndrome in adults. Ann Surg 2004; 240:595.
  4. Peek GJ, Moore HM, Moore N, et al. Extracorporeal membrane oxygenation for adult respiratory failure. Chest 1997; 112:759.
  5. Lewandowski K, Rossaint R, Pappert D, et al. High survival rate in 122 ARDS patients managed according to a clinical algorithm including extracorporeal membrane oxygenation. Intensive Care Med 1997; 23:819.
  6. Ullrich R, Lorber C, Röder G, et al. Controlled airway pressure therapy, nitric oxide inhalation, prone position, and extracorporeal membrane oxygenation (ECMO) as components of an integrated approach to ARDS. Anesthesiology 1999; 91:1577.
  7. Rich PB, Awad SS, Kolla S, et al. An approach to the treatment of severe adult respiratory failure. J Crit Care 1998; 13:26.
  8. Kolla S, Awad SS, Rich PB, et al. Extracorporeal life support for 100 adult patients with severe respiratory failure. Ann Surg 1997; 226:544.
  9. Australia and New Zealand Extracorporeal Membrane Oxygenation (ANZ ECMO) Influenza Investigators, Davies A, Jones D, et al. Extracorporeal Membrane Oxygenation for 2009 Influenza A(H1N1) Acute Respiratory Distress Syndrome. JAMA 2009; 302:1888.
  10. Brogan TV, Thiagarajan RR, Rycus PT, et al. Extracorporeal membrane oxygenation in adults with severe respiratory failure: a multi-center database. Intensive Care Med 2009; 35:2105.
  11. Noah MA, Peek GJ, Finney SJ, et al. Referral to an extracorporeal membrane oxygenation center and mortality among patients with severe 2009 influenza A(H1N1). JAMA 2011; 306:1659.
  12. Peek GJ, Mugford M, Tiruvoipati R, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. Lancet 2009; 374:1351.
  13. Pham T, Combes A, Rozé H, et al. Extracorporeal membrane oxygenation for pandemic influenza A(H1N1)-induced acute respiratory distress syndrome: a cohort study and propensity-matched analysis. Am J Respir Crit Care Med 2013; 187:276.
  14. Bartlett RH. Clinical Research in Acute Fatal Illness: Lessons From Extracorporeal Membrane Oxygenation. J Intensive Care Med 2016; 31:456.
  15. Posluszny J, Rycus PT, Bartlett RH, et al. Outcome of Adult Respiratory Failure Patients Receiving Prolonged (≥14 Days) ECMO. Ann Surg 2016; 263:573.
  16. Robba C, Ortu A, Bilotta F, et al. Extracorporeal membrane oxygenation for adult respiratory distress syndrome in trauma patients: A case series and systematic literature review. J Trauma Acute Care Surg 2017; 82:165.
  17. Boissier F, Bagate F, Schmidt M, et al. Extracorporeal Life Support for Severe Acute Chest Syndrome in Adult Sickle Cell Disease: A Preliminary Report. Crit Care Med 2019; 47:e263.
  18. Combes A, Hajage D, Capellier G, et al. Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome. N Engl J Med 2018; 378:1965.
  19. Harrington D, Drazen JM. Learning from a Trial Stopped by a Data and Safety Monitoring Board. N Engl J Med 2018; 378:2031.
  20. Munshi L, Walkey A, Goligher E, et al. Venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome: a systematic review and meta-analysis. Lancet Respir Med 2019; 7:163.
  21. Aoyama H, Uchida K, Aoyama K, et al. Assessment of Therapeutic Interventions and Lung Protective Ventilation in Patients With Moderate to Severe Acute Respiratory Distress Syndrome: A Systematic Review and Network Meta-analysis. JAMA Netw Open 2019; 2:e198116.
  22. Combes A, Peek GJ, Hajage D, et al. ECMO for severe ARDS: systematic review and individual patient data meta-analysis. Intensive Care Med 2020; 46:2048.
  23. Trudzinski FC, Kaestner F, Schäfers HJ, et al. Outcome of Patients with Interstitial Lung Disease Treated with Extracorporeal Membrane Oxygenation for Acute Respiratory Failure. Am J Respir Crit Care Med 2016; 193:527.
  24. Younger JG, Schreiner RJ, Swaniker F, et al. Extracorporeal resuscitation of cardiac arrest. Acad Emerg Med 1999; 6:700.
  25. Massetti M, Tasle M, Le Page O, et al. Back from irreversibility: extracorporeal life support for prolonged cardiac arrest. Ann Thorac Surg 2005; 79:178.
  26. Smedira NG, Blackstone EH. Postcardiotomy mechanical support: risk factors and outcomes. Ann Thorac Surg 2001; 71:S60.
  27. Kelly RB, Porter PA, Meier AH, et al. Duration of cardiopulmonary resuscitation before extracorporeal rescue: how long is not long enough? ASAIO J 2005; 51:665.
  28. Combes A, Leprince P, Luyt CE, et al. Outcomes and long-term quality-of-life of patients supported by extracorporeal membrane oxygenation for refractory cardiogenic shock. Crit Care Med 2008; 36:1404.
  29. Pagani FD, Aaronson KD, Swaniker F, Bartlett RH. The use of extracorporeal life support in adult patients with primary cardiac failure as a bridge to implantable left ventricular assist device. Ann Thorac Surg 2001; 71:S77.
  30. Kagawa E, Dote K, Kato M, et al. Should we emergently revascularize occluded coronaries for cardiac arrest?: rapid-response extracorporeal membrane oxygenation and intra-arrest percutaneous coronary intervention. Circulation 2012; 126:1605.
  31. Bednarczyk JM, White CW, Ducas RA, et al. Resuscitative extracorporeal membrane oxygenation for in hospital cardiac arrest: a Canadian observational experience. Resuscitation 2014; 85:1713.
  32. Chang CH, Chen HC, Caffrey JL, et al. Survival Analysis After Extracorporeal Membrane Oxygenation in Critically Ill Adults: A Nationwide Cohort Study. Circulation 2016; 133:2423.
  33. Thiagarajan RR, Barbaro RP, Rycus PT, et al. Extracorporeal Life Support Organization Registry International Report 2016. ASAIO J 2017; 63:60.
  34. Pontailler M, Demondion P, Lebreton G, et al. Experience with Extracorporeal Life Support for Cardiogenic Shock in the Older Population more than 70 Years of Age. ASAIO J 2017; 63:279.
  35. Chung M, Zhao Y, Strom JB, et al. Extracorporeal Membrane Oxygenation Use in Cardiogenic Shock: Impact of Age on In-Hospital Mortality, Length of Stay, and Costs. Crit Care Med 2019; 47:e214.
  36. Bréchot N, Hajage D, Kimmoun A, et al. Venoarterial extracorporeal membrane oxygenation to rescue sepsis-induced cardiogenic shock: a retrospective, multicentre, international cohort study. Lancet 2020; 396:545.
  37. Shin TG, Choi JH, Jo IJ, et al. Extracorporeal cardiopulmonary resuscitation in patients with inhospital cardiac arrest: A comparison with conventional cardiopulmonary resuscitation. Crit Care Med 2011; 39:1.
  38. Chen YS, Lin JW, Yu HY, et al. Cardiopulmonary resuscitation with assisted extracorporeal life-support versus conventional cardiopulmonary resuscitation in adults with in-hospital cardiac arrest: an observational study and propensity analysis. Lancet 2008; 372:554.
  39. Ortega-Deballon I, Hornby L, Shemie SD, et al. Extracorporeal resuscitation for refractory out-of-hospital cardiac arrest in adults: A systematic review of international practices and outcomes. Resuscitation 2016; 101:12.
  40. https://www.elso.org/Portals/0/ELSO%20Guidelines%20General%20All%20ECLS%20Version%201_4.pdf (Accessed on July 23, 2018).
  41. Tsai HC, Chang CH, Tsai FC, et al. Acute Respiratory Distress Syndrome With and Without Extracorporeal Membrane Oxygenation: A Score Matched Study. Ann Thorac Surg 2015; 100:458.
  42. Ferguson ND, Fan E, Camporota L, et al. The Berlin definition of ARDS: an expanded rationale, justification, and supplementary material. Intensive Care Med 2012; 38:1573.
  43. Braune S, Sieweke A, Brettner F, et al. The feasibility and safety of extracorporeal carbon dioxide removal to avoid intubation in patients with COPD unresponsive to noninvasive ventilation for acute hypercapnic respiratory failure (ECLAIR study): multicentre case-control study. Intensive Care Med 2016; 42:1437.
  44. Ouweneel DM, Schotborgh JV, Limpens J, et al. Extracorporeal life support during cardiac arrest and cardiogenic shock: a systematic review and meta-analysis. Intensive Care Med 2016; 42:1922.
  45. Grant C Jr, Richards JB, Frakes M, et al. ECMO and Right Ventricular Failure: Review of the Literature. J Intensive Care Med 2021; 36:352.
  46. Debaty G, Babaz V, Durand M, et al. Prognostic factors for extracorporeal cardiopulmonary resuscitation recipients following out-of-hospital refractory cardiac arrest. A systematic review and meta-analysis. Resuscitation 2017; 112:1.
  47. Hakim AH, Ahmad U, McCurry KR, et al. Contemporary Outcomes of Extracorporeal Membrane Oxygenation Used as Bridge to Lung Transplantation. Ann Thorac Surg 2018; 106:192.
  48. Zhang JJY, Ong JA, Syn NL, et al. Extracorporeal Membrane Oxygenation in Pregnant and Postpartum Women: A Systematic Review and Meta-Regression Analysis. J Intensive Care Med 2021; 36:220.
  49. Rush B, Wiskar K, Berger L, Griesdale D. Trends in Extracorporeal Membrane Oxygenation for the Treatment of Acute Respiratory Distress Syndrome in the United States. J Intensive Care Med 2017; 32:535.
  50. Schmidt M, Tachon G, Devilliers C, et al. Blood oxygenation and decarboxylation determinants during venovenous ECMO for respiratory failure in adults. Intensive Care Med 2013; 39:838.
  51. Wang D, Zhou X, Liu X, et al. Wang-Zwische double lumen cannula-toward a percutaneous and ambulatory paracorporeal artificial lung. ASAIO J 2008; 54:606.
  52. Madershahian N, Nagib R, Wippermann J, et al. A simple technique of distal limb perfusion during prolonged femoro-femoral cannulation. J Card Surg 2006; 21:168.
  53. Navia JL, Atik FA, Beyer EA, Ruda Vega P. Extracorporeal membrane oxygenation with right axillary artery perfusion. Ann Thorac Surg 2005; 79:2163.
  54. Sklar MC, Sy E, Lequier L, et al. Anticoagulation Practices during Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure. A Systematic Review. Ann Am Thorac Soc 2016; 13:2242.
  55. Spinelli E, Bartlett RH. Anemia and Transfusion in Critical Care: Physiology and Management. J Intensive Care Med 2016; 31:295.
  56. Mazzeffi M, Greenwood J, Tanaka K, et al. Bleeding, Transfusion, and Mortality on Extracorporeal Life Support: ECLS Working Group on Thrombosis and Hemostasis. Ann Thorac Surg 2016; 101:682.
  57. Wilson JM, Bower LK, Fackler JC, et al. Aminocaproic acid decreases the incidence of intracranial hemorrhage and other hemorrhagic complications of ECMO. J Pediatr Surg 1993; 28:536.
  58. Biswas AK, Lewis L, Sommerauer JF. Aprotinin in the management of life-threatening bleeding during extracorporeal life support. Perfusion 2000; 15:211.
  59. Peek, G, Wittenstein, et al. Management of bleeding during ECLS. In: ECMO in Critical Care, Van Meurs, K, Lally, KP, Peek, G, Zwischenberger, JB (Eds), Extracorporeal life support organization, Ann Arbor 2005.
  60. Bui JD, Despotis GD, Trulock EP, et al. Fatal thrombosis after administration of activated prothrombin complex concentrates in a patient supported by extracorporeal membrane oxygenation who had received activated recombinant factor VII. J Thorac Cardiovasc Surg 2002; 124:852.
  61. Wittenstein B, Ng C, Ravn H, Goldman A. Recombinant factor VII for severe bleeding during extracorporeal membrane oxygenation following open heart surgery. Pediatr Crit Care Med 2005; 6:473.
  62. Anselmi A, Guinet P, Ruggieri VG, et al. Safety of recombinant factor VIIa in patients under extracorporeal membrane oxygenation. Eur J Cardiothorac Surg 2016; 49:78.
  63. Parzy G, Daviet F, Persico N, et al. Prevalence and Risk Factors for Thrombotic Complications Following Venovenous Extracorporeal Membrane Oxygenation: A CT Scan Study. Crit Care Med 2020; 48:192.
  64. Hartley EL, Singh N, Barrett N, et al. Screening pulmonary angiogram and the effect on anticoagulation strategies in severe respiratory failure patients on venovenous extracorporeal membrane oxygenation. J Thromb Haemost 2020; 18:217.
  65. Chapman JT, Breeding J, Kerr SJ, et al. CNS Complications in Adult Patients Treated With Extracorporeal Membrane Oxygenation. Crit Care Med 2021; 49:282.
  66. Mateen FJ, Muralidharan R, Shinohara RT, et al. Neurological injury in adults treated with extracorporeal membrane oxygenation. Arch Neurol 2011; 68:1543.
  67. Cornell T, Wyrick P, Fleming G, et al. A case series describing the use of argatroban in patients on extracorporeal circulation. ASAIO J 2007; 53:460.
  68. Saeed O, Jakobleff WA, Forest SJ, et al. Hemolysis and Nonhemorrhagic Stroke During Venoarterial Extracorporeal Membrane Oxygenation. Ann Thorac Surg 2019; 108:756.
  69. Fernando SM, Scott M, Talarico R, et al. Association of Extracorporeal Membrane Oxygenation With New Mental Health Diagnoses in Adult Survivors of Critical Illness. JAMA 2022; 328:1827.
  70. Thiele H, Sick P, Boudriot E, et al. Randomized comparison of intra-aortic balloon support with a percutaneous left ventricular assist device in patients with revascularized acute myocardial infarction complicated by cardiogenic shock. Eur Heart J 2005; 26:1276.
  71. McNamee JJ, Gillies MA, Barrett NA, et al. Effect of Lower Tidal Volume Ventilation Facilitated by Extracorporeal Carbon Dioxide Removal vs Standard Care Ventilation on 90-Day Mortality in Patients With Acute Hypoxemic Respiratory Failure: The REST Randomized Clinical Trial. JAMA 2021; 326:1013.
  72. Peek GJ, Killer HM, Reeves R, et al. Early experience with a polymethyl pentene oxygenator for adult extracorporeal life support. ASAIO J 2002; 48:480.
  73. Toomasian JM, Schreiner RJ, Meyer DE, et al. A polymethylpentene fiber gas exchanger for long-term extracorporeal life support. ASAIO J 2005; 51:390.
  74. Khoshbin E, Roberts N, Harvey C, et al. Poly-methyl pentene oxygenators have improved gas exchange capability and reduced transfusion requirements in adult extracorporeal membrane oxygenation. ASAIO J 2005; 51:281.
  75. Malfertheiner MV, Philipp A, Lubnow M, et al. Hemostatic Changes During Extracorporeal Membrane Oxygenation: A Prospective Randomized Clinical Trial Comparing Three Different Extracorporeal Membrane Oxygenation Systems. Crit Care Med 2016; 44:747.
  76. Hoshi H, Shinshi T, Takatani S. Third-generation blood pumps with mechanical noncontact magnetic bearings. Artif Organs 2006; 30:324.
  77. Lawson DS, Ing R, Cheifetz IM, et al. Hemolytic characteristics of three commercially available centrifugal blood pumps. Pediatr Crit Care Med 2005; 6:573.
  78. Zhang H, Annich GM, Miskulin J, et al. Nitric oxide releasing silicone rubbers with improved blood compatibility: preparation, characterization, and in vivo evaluation. Biomaterials 2002; 23:1485.
  79. Bharat A, Pham DT, Prasad SM. Ambulatory Extracorporeal Membrane Oxygenation: A Surgical Innovation for Adult Respiratory Distress Syndrome. JAMA Surg 2016; 151:478.
Topic 1625 Version 57.0

References