Near Infrared Spectroscopy in Cyanotic Congenital Heart Disease
Condition: Congenital Heart Defects
MeSH terms: Heart Diseases; Heart Defects, Congenital
Study type: Observational

Summary: 
      We are conducting a prospective cohort study of 20 children with cyanotic congenital heart
      disease who are admitted for cardiac surgery. We will record cerebral and somatic near
      infrared spectroscopy (NIRS) at two sites - forehead and flank regions using the Covidien
      INVOS™ 5100C Cerebral / Somatic Oximeter. The monitoring will begin one hour pre-operatively
      (baseline) and continue until 48hours post-operatively. We will also take measurements prior
      to discharge from hospital. Baseline demographics, physiological and laboratory variables
      will be recorded. Clinical outcome variables including mortality, duration of intensive care
      unit (ICU) stay, duration of mechanical ventilation, inotropic support and feed tolerance
      will also be recorded.
    

Detailed description: 
      NIRS has been used to predict short term clinical outcomes (low cardiac output states,
      prolonged ventilation, and prolonged hospital stay) and long term clinical outcomes (reduced
      neurodevelopmental scores at 1year, radiological changes on magnetic resonance imaging). NIRS
      has also been tested against traditional markers of global tissue perfusion like mixed venous
      saturation and serum lactate, however, results from these studies are mixed. There is
      insufficient prospective data evaluating NIRs with direct clinical outcomes and uncertainty
      about the threshold value or the duration below a threshold value that leads to tissue
      injury. Because of this lack of data, the benefit and risk of management strategies targeted
      to improve NIRS values remains unknown.

      We will characterize the time series of cerebral and somatic oximetry, pulse oximetry and
      partial pressure of arterial oxygen in the cyanotic child undergoing surgical repair of a
      congenital heart defect. We will then determine the correlation between the time series if
      any. This new information will advance our understanding of the hemodynamic changes that
      occur in the perioperative period and may lead to new therapeutic targets.

      The primary hypothesis is that there is a delayed increase in cerebral and somatic oximetry
      post-operation as compared pulse oximetry (SpO2) and partial pressure of arterial oxygen
      (PaO2) which occur immediately.

      The secondary hypothesis is to establish the applicability of a desaturation score (decrease
      of 20% in area under the curve [AUC] over an hour) in the early prediction of adverse
      outcomes.

      The oximetry probes will be placed pre-induction of anesthesia (to determine baseline) and
      recordings will be continuous throughout the operation and 48hours post-operatively. Children
      undergoing cardiac surgery generally stay in the hospital for 1-2weeks. We will also take
      oximetry measurements prior to discharge from hospital (to determine the new steady state).
      Sites measured are cerebral (forehead) and somatic (left flank).
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children with cyanotic congenital heart disease undergoing cardiac surgery
      
Keywords: Spectroscopy, Near-Infrared