Pediatric Extracorporeal Membrane Oxygenation

Etiology: Long term cardiopulmonary bypass to rest lungs in patients with respiratory failure used most often in patients in cardio-pulmonary failure due to meconium aspiration or persistent pulmonary hypertension or congenital diaphragmatic hernia or overwhelming sepsis or post-operative cardiac patients
— Arterio-venous (AV) extracorporeal membrane oxygenation (ECMO) used for heart-lung support
— Venous-venous (VV) ECMO used for respiratory support
— Patients are systemically heparinized to prevent clots in ECMO circuit which predisposes them to bleeding anywhere
Imaging CXR:
— Body wall edema due to being paralyzed on ventilator, complete opacification of lungs
— Arterial-venous ECMO in neonate: Tip of arterial cannula placed from right common carotid artery should be in the innominate artery and radiopaque tip of venous cannula placed from right internal jugular vein should be in the right atrium
— Venous-venous ECMO in neonate: Radiopaque tip of venous cannula placed from right internal jugular vein should be in the right atrium
— Venous-venous ECMO in older child: Tip of venous cannula should be near the junction of the right atrium and the inferior vena cava
Imaging AXR:
— Arterial-venous ECMO in older child: Tip of arterial cannula should be in the iliac artery and tip of venous cannula should be in the inferior vena cava
Imaging US:
— Neonatal brain needs to be screened before beginning for contraindications to ECMO such as pre-existing bleed or brain malformation or brain mass
— Brain needs to be screened regularly (often daily) for intracranial bleeding
— Bleeds can occur anywhere in brain including the cerebellum and not just in germinal matrix
— ECMO bleeds in brain may be hypoechoic rather than hyperechoic – bleeds are hyperechoic due to fibrin mesh within clotted blood but heparinized patients may not form a clot in a bleed and thus do not have a fibrin mesh and therefore have a hypoechoic bleed
DDX:
Complications:
— Catheter malposition
— Systemic anticoagulation can lead to bleeding anywhere in body but especially in brain so regular surveillance head ultrasound is performed
— Cerebral atrophy post ECMO
Treatment: If bleed occurs clinicians must decide which is more important – brain or lungs
Clinical: Patients are sedated while on ECMO making clinical exam very difficult so imaging is in the front line when screening for complications

Radiology Cases of Extracorporeal Membrane Oxygenation

Radiology Cases of Arterial-Venous Extracorporeal Membrane Oxygenation Normal Catheter Position

CXR of arterial-venous extracorporeal membrane oxygenation (ECMO) — CXR shows normal position of the arterial catheter tip in the aortic arch (aa) and normal position of the venous catheter tip in the right atrium (ra).

CXR of congenital diaphragmatic hernia — CXR AP shows complete opacification of the left hemithorax with mediastinal shift to the right and a small right pneumothorax. The arterial ECMO canula tip projects over the aortic arch and the venous ECMO canula tip projects over the right atrium. The nasogastric tube tip projects over the mid-esophagus.

CXR of arterial-venous extracorporeal membrane oxygenation (ECMO) — CXR shows normal position of the arterial catheter tip in the aortic arch and normal position of the venous catheter tip in the right atrium, both of which are shifted to the right by the diaphragmatic hernia. Note that the endotracheal tube, which is positioned between the two ECMO catheters, is also shifted to the right.

CXR and CT of post-infectious pneumatocele — CXR AP (above) shows the arterial catheter tip projecting over the aortic arch and the venous catheter tip projecting over the right atrium. There is bilateral diffuse airspace disease and bilateral pleural effusions. A cystic lesion is seen in the right lower lobe. Axial CT without contrast of the chest (below left) shows the cystic lesion is thin walled and communicates with the bronchial tree and has multiple septations (below right).

CXR of transesophageal echocardiogram probe — CXR AP shows an open chest with an ECMO arterial catheter tip in the aortic arch and an ECMO venous catheter tip in the right atrium. A wide-diameter tube with a sensor at the end projects over the esophagus which represents a transesophageal echocardiogram probe.

Radiology Cases of Venous-Venous Extracorporeal Membrane Oxygenation Normal Catheter Position

CXR of venous-venous extracorporeal membrane oxygenation (ECMO) — CXR shows normal position of the venous catheter tip in the right atrium.

CXR of venous-venous extracorporeal membrane oxygenation (ECMO) — CXR shows normal position of the venous catheter tip near the junction of the right atrium and the inferior vena cava.

AXR of arterial-venous extracorporeal membrane oxygenation (ECMO) — AXR shows normal position of the arterial catheter tip in the right iliac artery and normal position of the venous catheter tip in the mid inferior vena cava.

Radiology Cases of Venous-Venous Extracorporeal Membrane Oxygenation Normal Catheter Position With Bilateral Hemothorax

US of hemothorax as a complication of extracorporeal membrane oxygenation — CXR AP (above) shows correct position of the ECMO venous-venous catheter tip near the junction of the right atrium and the inferior vena cava. There are bilateral pleural effusions most prominently seen in the apex of the lungs. Transverse US of the right hemithorax (below left) shows echogenic pleural fluid lateral to the atelectatic right lower lobe. Sagittal US of the left hemithorax (below right) shows echogenic pleural fluid inferior to the atelectatic left lower lobe and superior to the spleen.

Radiology Cases of Extracorporeal Membrane Oxygenation Catheter Malposition

CXR of arterial-venous extracorporeal membrane oxygenation (ECMO) — CXR shows normal position of the arterial catheter tip in the aortic arch and abnormal position of the venous catheter tip (represented by a radio-opaque point) in the superior vena cava. Further advancement of the tip into the right atrium is necessary.

CXR of malposition ECMO catheter in patient with congenital diaphragmatic hernia — CXR shows normal position of the arterial catheter tip in the aortic arch and abnormal position of the venous catheter tip (represented by a radio-opaque point) in the superior vena cava. Further advancement of the tip into the right atrium is necessary. Multiple cystic structures are present in the left hemithorax. The lungs are densely opacified.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Hemothorax

US of hemothorax in patient on extracorporeal membrane oxygenation (ECMO) — Sagittal and transverse US of the right chest shows a complex fluid collection in the right pleural space.

US of hemothorax as a complication of extracorporeal membrane oxygenation — CXR AP (above) shows correct position of the ECMO venous-venous catheter tip near the junction of the right atrium and the inferior vena cava. There are bilateral pleural effusions most prominently seen in the apex of the lungs. Transverse US of the right hemithorax (below left) shows echogenic pleural fluid lateral to the atelectatic right lower lobe. Sagittal US of the left hemithorax (below right) shows echogenic pleural fluid inferior to the atelectatic left lower lobe and superior to the spleen.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Intramuscular Hematoma

CT of intramuscular hematoma in patient on extracorporeal membrane oxygenation (ECMO) — Axial CT with contrast of the chest shows hematomas in the right sternocleidomastoid muscle (above) near the ECMO catheter insertion site and left pectoralis major muscle.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Subdural Hematoma

US of subdural hematoma and intracerebral hemorrhage in patient on extracorporeal membrane oxygenation (ECMO) — Coronal US of the brain (below) shows echogenic material in right subdural space. Coronal and sagittal US of the brain (above) shows a right parietal round mixed echogenicity lesion.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Intracerebral Hemorrhage

US of intracerebral hemorrhage in a patient on extracorporeal membrane oxygenation (ECMO) — Coronal and sagittal US of the brain shows a large, round echogenic lesion in the left parietal lobe.

CT of intracerebral hemorrhage in a patient on extracorporeal membrane oxygenation (ECMO) — Sagittal, coronal and axial CT without contrast of the brain shows a large, round high density lesion in the right parietal lobe.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Intraventricular Hemorrhage

CT of intraventricular hemorrhage, intracerebral hemorrhage, and cerebral atrophy in a patient on extracorporeal membrane oxygenation (ECMO) — Axial CT without contrast of the brain shows mixed-density fluid in the left lateral ventricle posteriorly and mixed-density fluid in the left parietal-occipital lobe. There is also diffuse prominence of the sulci and ventricular system.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Cerebellar Hemorrhage

CT of cerebellar hemorrhage on extracorporeal membrane oxygenation (ECMO) — Axial and coronal CT without contrast of the brain shows three round mixed density lesions in the cerebellum compressing the fourth ventricle and causing hydrocephalus. The fluid-fluid levels in the lesions were felt to represent active bleeding.

Radiology Cases of Extracorporeal Membrane Oxygenation Causing Cerebral Atrophy

CT of cerebral atrophy after being on extracorporeal membrane oxygenation (ECMO) — Axial CT without contrast of the brain shows diffuse prominence of the sulci and ventricular system.