title: Neonatal decompensation before surgery in hypoplastic left heart syndrome: a case control study.
abstract: OBJECTIVE
  Prior to Norwood 1 surgery, neonates with hypoplastic left heart syndrome (HLHS) are at risk of decompensation from systemic underperfusion secondary to pulmonary overcirculation. We examined whether preoperative temporal profiles of physiological and laboratory variables differed between neonates who did and did not decompensate preoperatively.
  
  
  METHODS
  Case control study.
  
  
  METHODS
  Paediatric Intensive Care Unit, 2002-2013.
  
  
  METHODS
  Eighty-five neonates with HLHS, matched by birth weight and admission date.
  
  
  METHODS
  Decompensation was defined as the need for emergency intubation and ventilation due to clinically diagnosed impaired systemic oxygen delivery. The end point was time of decompensation (cases, n=33) or discharge for surgery (controls, n=52). Variable trajectories were modelled non-linearly using generalised estimating equations.
  
  
  RESULTS
  Decompensation occurred on median (IQR) day 3 (2-4) of life in cases, with surgery occurring on day 4 (3-7) in controls. Oxygen saturation and blood pressure trajectories were identical between groups (p>0.2). Heart and respiratory rates increased with time overall, but significantly faster in cases than controls; by an average of 4.0 bpm/day versus 1.4 bpm/day (p=0.002) and 5.3 respirations/minute/day versus 1.5 respirations/minute/day, respectively, (p=0.003). Although metabolic blood gas components began to decline subtly 24 h before clinical decompensation, they remained in the normal range for much of this period.
  
  
  CONCLUSIONS
  Heart and respiratory rates, and metabolic acid base trajectories show subtle differences prior to decompensation in neonates with HLHS. These findings highlight the importance of evaluating rates of change rather than absolute values of physiological and laboratory variables.
authors.affiliation: Evelina Children's Hospital, London, UK.
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Sheward
authors.affiliation: Evelina Children's Hospital, London, UK.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Murdoch
authors.affiliation: Evelina Children's Hospital, London, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Durward
authors.affiliation: Evelina Children's Hospital, London, UK.
authors.forename: Shane M
authors.initials: SM
authors.lastname: Tibby
mesh_terms: D001724:Birth Weight; D002245:Carbon Dioxide / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006333:Heart Failure / Q000209:etiology* / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000097:blood / Q000150:complications* / Q000503:physiopathology / Q000601:surgery; D007231:Infant, Newborn; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D058327:Norwood Procedures; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010313:Partial Pressure; D011379:Prognosis; D011652:Pulmonary Circulation / Q000502:physiology; D056152:Respiratory Rate / Q000502:physiology; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: Cardiology; Intensive Care; Monitoring; Physiology