Carotid artery and jugular vein ligation with and without hypoxia in the rat

Cerebral aspects of neonatal extracorporeal membrane oxygenation: a review

BACKGROUND

Neonatal extracorporeal membrane oxygenation (ECMO) is a lifesaving therapeutic approach in newborns suffering from severe, but potentially reversible, respiratory insufficiency, mostly complicated by neonatal persistent pulmonary hypertension. However, cerebral damage, intracerebral hemorrhage as well as ischemia belong to the most devastating complications of ECMO.

OBJECTIVES

The objectives are to give insights into what is known from the literature concerning cerebral damage related to neonatal ECMO treatment for pulmonary reasons.

METHODS

A short introduction to ECMO indications and technical aspects of ECMO are provided for a better understanding of the process. The remainder of this review focuses on outcome and especially on (potential) risk factors for cerebral hemorrhage and ischemia during ECMO treatment.

RESULTS

Although neonatal ECMO treatment shows improved outcome compared to conservative treatment in cases of severe respiratory insufficiency, it is related to disturbances in various aspects of neurodevelopmental outcome. Risk factors for cerebral damage are either related to the patient's disease, EMCO treatment itself, or a combination of both.

CONCLUSION

It is of ongoing importance to further understand pathophysiological mechanisms resulting in cerebral hemorrhage and ischemia due to ECMO and to develop neuroprotective strategies and approaches.

Systemic hyperthermia induces ischemic brain injury in neonatal mice with ligated carotid artery and jugular vein

Postnatal d 7 (p7) or p12 mice had their right carotid artery (CA) and jugular vein (JV) ligated to mimic veno-arterial (VA) access for extracorporeal membrane oxygenation (ECMO). At p9-11 (early) or p19-21 (late) mice were exposed to hyperthermia or normothermia followed by assessment of neuropathological injury score. In separate cohorts of mice, cerebral and peripheral blood flow (CBF, PBF) and cerebral ATP content was measured. Hyperthermia resulted in ischemic brain injury in 57% and 77% of mice subjected to early or late hyperthermia, respectively. Isolated CA+JV ligation induced minimal injury (score 0.47 +/- 0.34) in 2/8 mice from the late normothermia group. No cerebral injury was detected in mice subjected to early normothermia. In 3/19 shams (2/10 early, 1/9 late) hyperthermia induced a subtle (score, 0.6 +/- 0.27) injury in the ipsilateral to the site of surgery cortex. CBF and PBF increased in response to hyperthermia in all mice. The rise in CBF was significantly attenuated in the "ligated" versus intact hemisphere, which was associated with a profound depletion of ATP content. Systemic hyperthermia induces ischemic brain injury in mice with ligated CA+JV. We speculate that hyperthermia/fever can be a potential risk factor for brain injury in infants treated with VA ECMO.

The effect of extracorporeal life support on the brain: a focus on ECMO

Extracorporeal membrane oxygenation (ECMO) therapy has significantly improved outcome in the newborn, pediatric, and adult patient in respiratory and cardiac failure. Despite this therapy providing a life-saving technology, the morbidity in patients treated with ECMO therapy is primarily related to neurologic alterations and not pulmonary findings. For ECMO, this is not unexpected since most patients are being placed on ECMO support because of severe hypoxemia, with ECMO being considered a rescue therapy for respiratory failure in most instances. As use of ECMO becomes common place for infants and children in respiratory failure, our investigations into the outcome of these children must focus not only on survival versus nonsurvival, but on the causes of morbidity in this population. A further understanding of factors associated with morbidity may allow us to alter techniques used in extracorporeal life support (ECLS), hopefully to improve our long-term outcome in this population, while allowing us to expand use of these technologies to other populations such as the premature infant. This article will focus on the effect of ECMO on the brain, with the following chapter by Dr. Richard Jonas outlining the effect of cardiopulmonary bypass on the brain.

Mechanical Cardiopulmonary Support of Infants and Children With Congenital Heart Disease

Cardiac indications for the use of mechanical cardiopulmo nary support techniques in infants and children include short-term circulatory support during reversible myocardial failure, cardiopulmonary support before and after cardiac surgery, and a bridge to cardiac transplantation. For practi cal purposes, 3 modalities are currently available for these patients: extracorporeal membrane oxygenation, use of ven tricular assist devices, and intra-aortic balloon pump coun terpulsation. Although a variety of devices are available for larger patients, the need for smaller sizes and a wider range of sizes has delayed their use in children. This article sum marizes the current systems available for children as well as indications and outcome data related to their use in infants and children with congenital or acquired heart disease. Copyright © 2001 by W.B. Saunders Company.