Relative plasma Brain Natriuretic Peptide (BNP) level may predict ability to wean from extracorporeal life support (ECLS)

  • Dr Timothy Thiruchelvam, Intensive Care Unit, Royal Childrens Hospital, Melbourne, Australia
  • Dr Bryn Jones, Department of Cardiology, Royal Childrens Hospital, Melbourne, Australia
  • Dr Michael Cheung, The Royal Children's Hopsital, Melbourne, Australia
  • Dr Yves D'Udekum, Department of Cardiac Surgery, Royal Childrens Hospital, Melbourne, Australia
  • Dr Lara Shekerdemian, Intensive Care Unit, Royal Childrens Hospital, Melbourne, Australia
  • A/Prof W Butt, Intensive Care Unit, Royal Childrens Hospital, Melbourne, Australia

    • Objective:
    To determine whether the relative change in plasma BNP during weaning from ECLS predicts successful separation from mechanical support in children.

    Methods:
    A prospective cohort study, in children receiving ECLS for cardiac support in a tertiary paediatric intensive care unit between December 2007 and November 2008. Weaning duration was calculated (t1-t0) where t0 was the time at which ECLS was maximal, immediately prior to commencing weaning, and t1 was the time of the final decision whether or not to decannulate. Plasma BNP samples were taken times t0 and t1 (BNP0, BNP1 respectively)and the plasma BNP ratio (BNP1:BNP0) was calculated for each weaning attempt. The ECLS team were blind to plasma BNP levels.

    Results:
    Nineteen weaning attempts were made in eighteen children, median age 101 days (range 1 day-15.7 years). Thirteen patients required ECLS after surgery for congenital heart disease, two had uncontrolled arrhythmia and three had refractory septic shock. The overall median duration of weaning (t1-t0) was 18.5 hours (range 3-92.5 hours). Median BNP0 was 600 pg/ml (IQR 253-635 pg/ml) and BNP1 was 555 pg/ml (IQR 353-763 pg/ml). Twelve weaning attempts were successful, and seven were not. Weaning time t1-t0 was 19.8 hours and 16.0 hours for successful and unsuccessful groups respectively (p=0.23). BNP1:BNP0 was lower in patients that were successfully weaned (median 0.86, range0.1-2.0), than for those who could not be weaned median 2.0 (0.9-3.3) (p=0.009).

    Conclusions:
    BNP1:BNP0 may be a useful adjunctive predictor of successful weaning from ECLS in children.