Neonatal extracorporeal membrane oxygenation--a bridging technique

Prognostic value of cerebral tissue oxygen saturation during neonatal extracorporeal membrane oxygenation

Objectives

Extracorporeal membrane oxygenation support is indicated in severe and refractory respiratory or circulatory failures. Neurological complications are typically represented by acute ischemic or hemorrhagic lesions, which induce higher morbidity and mortality. The primary goal of this study was to assess the prognostic value of cerebral tissue oxygen saturation (StcO₂) on mortality in neonates and young infants treated with ECMO. A secondary objective was to evaluate the association between StcO₂ and the occurrence of cerebral lesions.

Study design

This was a prospective study in infants < 3 months of age admitted to a pediatric intensive care unit and requiring ECMO support.

Measurements

The assessment of cerebral perfusion was made by continuous StcO₂ monitoring using near-infrared spectroscopy (NIRS) sensors placed on the two temporo-parietal regions. Neurological lesions were identified by MRI or transfontanellar echography.

Results

Thirty-four infants <3 months of age were included in the study over a period of 18 months. The ECMO duration was 10±7 days. The survival rate was 50% (17/34 patients), and the proportion of brain injuries was 20% (7/34 patients). The mean StcO₂ during ECMO in the non-survivors was reduced in both hemispheres (p = 0.0008 right, p = 0.03 left) compared to the survivors. StcO₂ was also reduced in deceased or brain-injured patients compared to the survivors without brain injury (p = 0.002).

Conclusion

StcO₂ appears to be a strong prognostic factor of survival and of the presence of cerebral lesions in young infants during ECMO.

Clinical Research in Acute Fatal Illness

Clinical research to evaluate the effectiveness of life support systems in acute fatal illness has unique problems of logistics, ethics, and consent. There have been 10 prospective comparative trials of extracorporeal membrane oxygenation in acute fatal respiratory failure, utilizing different study designs. The trial designs were prospective controlled randomized, prospective adaptive randomized, sequential, and matched pairs. The trials were reviewed with regard to logistics, ethics, consent, statistical methods, economics, and impact. The matched pairs method is the best study design for evaluation of life support systems in acute fatal illness.

Extracorporeal membrane oxygenation for adult respiratory failure

OBJECTIVES

To review the first 50 patients to receive extracorporeal membrane oxygenation (ECMO) for respiratory failure at Glenfield Hospital, and to compare them with published series of patients receiving positive pressure ventilation.

DESIGN

Retrospective chart review.

SETTING

Extracorporeal Life Support Organization/European Extracorporeal Life Support Organization recognized ECMO center.

PATIENTS

Fifty consecutive patients referred for ECMO with respiratory failure refractory to conventional management between 1989 and 1995.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Primary end point was survival to hospital discharge, 66%. Other data (mean and SD): Murray Lung Injury Score, 3.4 (0.5); ratio of PaO2 to fraction of inspired oxygen, 65 (36.9) mm Hg; duration of ventilation pre-ECMO, 76.5 (83.7 h); peak airway pressure, 39.6 (7.4) cm H2O; end-expiratory pressure, 10 (3.3) cm H2O; minute ventilation, 12.6 (3.32) L/min; age, 30.1 (10.8) years; duration of ECMO, 207.4 (177.8) h; and units of blood transfused, 19 (17.3). Survival was significantly better than two previously reported series of patients receiving positive pressure ventilation (55.6% and 42% survival), p=0.036 and p=0.0006. Odds ratio for improved survival was 0.46 (95% confidence interval, 0.22 to 0.97, p=0.036).

CONCLUSIONS

Survival with ECMO is 66% for adults with severe respiratory failure. ECMO should be considered in patients who remain hypoxic despite maximal positive pressure ventilation.