*1.3.4 ECMO start*

*Advances in Extracorporeal Membrane Oxygenation - Volume 3*

A serious problem in the ultrasound evaluation is the detection of an evolving pericardial effusion to the cardiac tamponade (**Figure 7**), due to the passage of wires or cannulae with rupture of the cardiac chambers [11, 14, 16]. Following anticoagulant therapy, necessary in VA-ECMO, the pericardial blood collection can become consistent at many hours from the positioning, and only a series of ultra-

Thrombosis is a major complication during VA-ECMO and can be catastrophic when cerebral embolism occurs [46, 47]. Factors predisposing thrombosis are related to the blood/circuit contact and its activation as well as to the turbulence linked to the lumen of the cannulae [48]. Thrombosis can be more or less evident at ultrasound, and a real pitfall is represented by spontaneous intracavitary echo contrast (smoke) [49]. The evaluation of the opening of the aortic valve guarantees a certain pulsatility to the flow and avoids the stasis linked to the stagnant flow on the closed valve and predictor of thrombosis [46–49]. If the valve does not open, it is necessary to open the valve through changes in the flow of the VA-ECMO, the use of inodilator drugs, or the insertion of the intra-aortic balloon pump (IABP), which also favours the decompression of the left ventricle. Furthermore, in these cases it is necessary to optimise anticoagulation, which can be evaluated with specific point of

The increase in the afterload generated by the VA-ECMO can promote mitralaortic valve regurgitation, compromising myocardial oxygenation and favouring

The difficult management of the patient in VA-ECMO must be accompanied by a continuous echocardiographic evaluation, carried out at least two times a day and whenever there is an unforeseen haemodynamic instability. The study of cardiac function should allow to optimise the flows of the mechanical support and the concomitant therapies. The ECHO evaluation must precede the start of the ECMO, follow the initial support phase, evaluate the evolution of the cardiac function in the stabilisation phase, and evaluate the cardiac functional recovery dictating the

the left ventricular distension not good for cardiac functional recovery.

sound analysis allows the recognition of this clinical situation.

*Presence of abundant pericardial effusion (light blue arrow) at TTE.*

care (thrombo-elastographic examination (TEG)) [50].

weaning time from the extracorporeal support.

**80**

**Figure 7.**

*1.3.3 ECHO in VA-ECMO*

At the start of the VA-ECMO, it is necessary to concentrate the attention on the venous drainage to be able to maintain the flow rate. Flow reduction may be due to obstructions (thrombus) or malposition of the cannula or hypovolaemia [11, 48]. A sudden reduction in perfusion pressure and low flow could lead to the search for aortic dissection or severe aortic valve regurgitation resulting in dilation of the left ventricle.

## *1.3.5 ECMO support*

VA-ECMO is usually a medium-short duration assay, allowing the recovery of cardiac function or the bridge to other solutions (LVAD or HTx). At this time, echocardiographic monitoring is essential to monitor cardiac function recovery or lack of it.

One of the major problems, especially in the peripheral configuration of the VA-ECMO, is the distension of the left ventricle, such as to increase the tele-diastolic pressure and compromise the functional recovery of the heart [51, 52]. During peripheral VA-ECMO, LV preload usually decreases, but the LV afterload increases, resulting in a distension of the left ventricle associated with failure to open the aortic valve. The flow thus becomes continuous and non-pulsatile with consequent stasis, tendency to thrombosis, and embolization. This situation compromises the recovery of the heart.

The therapeutic strategy consists in venting the left ventricle [52] (**Figure 8**). The opening of the aortic valve can be done simply by trying to reduce the ECMO flow, but almost always you have to proceed with the IABP or better with the use of Impella® (ABIOMED, Inc., 22 Cherry Hill Drive, Danvers, MA 01923, USA) [53]. The most effective system is the cannulation of the left ventricular apex through a mini-thoracotomy, a procedure that can be performed under ultrasound guidance [52]. Echocardiographic monitoring has a key role in monitoring the distension of the left ventricle which leads to an increase in capillary pressure, interstitial pulmonary oedema, and bi-ventricular insufficiency. An alternative but less effective venting system is represented by an EndoVent in the pulmonary artery that, rather than detecting the left ventricle as it would take, reduces its preload [54]. Another solution for left ventricular decompression, in patients receiving extracorporeal

#### **Figure 9.**

*TOE (4Ch view) of patient in VA-ECMO in which there is an extensive thrombotic formation of the left ventricle and of the left atrium.*

membrane oxygenation for myocardial failure, is represented by balloon atrial septostomy, used especially in paediatric patients [55, 56].

Echocardiography, through the evaluation of trans-aortic flow, is a precious instrument to measure CO during ECMO support as all CO monitoring methods are affected by errors.

The evaluation of distal perfusion is mandatory, and in most cases the distal hypoperfusion must be resolved by a retrograde perfusion cannula.

#### *1.3.6 Weaning from ECMO*

The echocardiographic evaluation reaches its peak in determining the timing and the possibility of weaning from ECMO [57]. Clearly weaning is possible only if the recovery of cardiac function is associated, as is evident, with the resolution of the pathological conditions determining the use of the VA-ECMO. An indirect sign of recovery of cardiac function is the increase in systolic-diastolic blood pressure. The echocardiographic parameters, which may suggest a safe weaning from the VA-ECMO, are the aortic VTI > 10 cm, the absence of cardiac tamponade, the partial recovery of the EF%, but above all an increase of the Sa wave at the TDI (>6 cm/s) [57, 58].

During the weaning of the VA-ECMO, the flow of ECMO is reduced, and clinical, haemodynamic, and echocardiographic parameters are evaluated. ECMO flows are usually not reduced below 1–2 L/min, due to the increased risk of thrombosis (**Figure 9**) of the low-flow circuit [59, 60]. If the patient remains with stable haemodynamic at low flow, they can be ready to be disconnected from the support. Weaning and de-cannulation are delicate phases, and careful haemodynamic and echocardiographic evaluation is needed to identify and promptly deal with contingent problems.

The ultrasonography evaluation also allows the vascular evaluation after de-cannulation.

#### **1.4 Conclusions**

Ultrasounds play a fundamental role in managing patients supported with ECMO, during all the different stages of assistance [10, 11, 14–16, 58], from

**83**

**Author details**

Geriatric Sciences, Rome, Italy

provided the original work is properly cited.

Luigi Tritapepe1,2,5\*, Ernesto Greco2,3,5 and Carlo Gaudio2,4,5

3 Cardiac Surgery, Sapienza University of Rome, Italy

\*Address all correspondence to: luigi.tritapepe@uniroma1.it

5 Policlinico Umberto I Hospital, Rome, Italy

1 Anaesthesia and Intensive Care, Sapienza University of Rome, Italy

4 Applied Medical Technical Sciences, Sapienza University of Rome, Italy

2 Department of Cardiovascular, Respiratory, Nephrology, Anaesthesiology and

*Echocardiography Evaluation in ECMO Patients DOI: http://dx.doi.org/10.5772/intechopen.85047*

recovery and weaning of support [10, 14–16, 34].

indication to cannulation, monitoring, and weaning. Either during circulatory or respiratory assistance, ultrasounds are fundamental to evaluate the cardiac function of the patients, providing information that determines appropriate patient selection. They are also needed to choose the best vascular access sites, guide the insertion of cannulas, monitor progress, detect complications, and help in determining

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Echocardiography Evaluation in ECMO Patients DOI: http://dx.doi.org/10.5772/intechopen.85047*

*Advances in Extracorporeal Membrane Oxygenation - Volume 3*

*TOE (4Ch view) of patient in VA-ECMO in which there is an extensive thrombotic formation of the left* 

membrane oxygenation for myocardial failure, is represented by balloon atrial

Echocardiography, through the evaluation of trans-aortic flow, is a precious instrument to measure CO during ECMO support as all CO monitoring methods are

The evaluation of distal perfusion is mandatory, and in most cases the distal

The echocardiographic evaluation reaches its peak in determining the timing and the possibility of weaning from ECMO [57]. Clearly weaning is possible only if the recovery of cardiac function is associated, as is evident, with the resolution of the pathological conditions determining the use of the VA-ECMO. An indirect sign of recovery of cardiac function is the increase in systolic-diastolic blood pressure. The echocardiographic parameters, which may suggest a safe weaning from the VA-ECMO, are the aortic VTI > 10 cm, the absence of cardiac tamponade, the partial recovery of the EF%, but above all an increase of the Sa wave at the TDI (>6 cm/s) [57, 58]. During the weaning of the VA-ECMO, the flow of ECMO is reduced, and clinical, haemodynamic, and echocardiographic parameters are evaluated. ECMO flows are usually not reduced below 1–2 L/min, due to the increased risk of thrombosis (**Figure 9**) of the low-flow circuit [59, 60]. If the patient remains with stable haemodynamic at low flow, they can be ready to be disconnected from the support. Weaning and de-cannulation are delicate phases, and careful haemodynamic and echocardiographic evaluation is needed to identify and promptly deal with contin-

The ultrasonography evaluation also allows the vascular evaluation after

Ultrasounds play a fundamental role in managing patients supported with ECMO, during all the different stages of assistance [10, 11, 14–16, 58], from

septostomy, used especially in paediatric patients [55, 56].

hypoperfusion must be resolved by a retrograde perfusion cannula.

**82**

gent problems.

de-cannulation.

**1.4 Conclusions**

**Figure 9.**

*ventricle and of the left atrium.*

affected by errors.

*1.3.6 Weaning from ECMO*

indication to cannulation, monitoring, and weaning. Either during circulatory or respiratory assistance, ultrasounds are fundamental to evaluate the cardiac function of the patients, providing information that determines appropriate patient selection. They are also needed to choose the best vascular access sites, guide the insertion of cannulas, monitor progress, detect complications, and help in determining recovery and weaning of support [10, 14–16, 34].
