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Targets, Thresholds and Interventions

Intervene and Make a Positive Difference

The INVOS® System's real time readings are automatic, making critical information continuously available to care teams. The sensitivity and specificity of rSO2 values provide vital site-specific perfusion information to quickly detect evolving problems and evaluate interventions that are most appropriate for each child's situation.

Pediatric rSO2 Targets and Thresholds

Targets and thresholds are expressed in rSO2 numerical values and percent changes from baseline. With the patient serving as his/her own control, customized clinical decisions are based on each patient's unique physiology and clinical situation.

Cerebral - High Blood Flow, High O2 Extraction
  • Typical rSO2 range: 60-80
  • Common intervention trigger: rSO2 < 50 or 20% change from rSO2 baseline
  • Critical threshold: rSO2 < 45 or 25% change from rSO2 baseline

Somatic / Peri-Renal - Variable Blood Flow, Lower O2 Extraction
  • Somatic rSO2 5-20 points higher than cerebral
  • Variances in the cerebral-somatic relationship may be indicative of pathology
Footnotes:
1. Hoffman GM, et al. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2005:12-21.
2. Petrova A and Mehta R. Pediatr Crit Care Med 2006;7:449-454.
3. Dent CL, et al. J Thorac Cardiovasc Surg. 2006 Jan;131(1):190-7.
4. Underlying data and case notes on file ISC-10007.

Operating Room Interventions to Improve rSO21

rSO2 may be affected by a host of variables in conjunction with the patient's condition. Some may include body positioning, muscular activity, circulating blood volume, cardiac function, peripheral vascular resistance, circulating hormones and venous pressure. While each hospital will have its own care protocols, these guidelines have been shown to improve rSO2.

Perfusion Imbalance
  • Optimize blood pressure
  • Identify mechanical obstruction (cannula or head position)
  • Increase cardiac output (pump flow)
  • Increase circulating volume
  • Increase CO2 to physiologic levels

Dysoxygenation
  • Increase FiO2
  • Increase hematocrit
  • Reintubate

Limited Ischemia Tolerance
  • Increase anesthetic depth
  • Neuroprotective agent
  • Additional cooling



Bilateral monitoring helps detect ischemia issues at the hemispheric level.

PICU Interventions to Improve Cerebral rSO2.2-3

Increase Cerebral Perfusion Pressure
  • Increase blood pressure
  • Increase systemic vascular resistance
  • Increase cardiac output
  • Decrease central venous pressure
  • Raise arterial partial pressure of carbon dioxide

Increase Arterial Oxygen Content
  • Transfuse red blood cells
  • Raise arterial partial pressure of oxygen

Reduce Cerebral Metabolic Rate
  • Control hyperthermia
  • Sedation
  • Reduce cerebral vascular resistance



Somatic monitoring augments cerebral data; typical placements include peri-renal and abdominal.

PICU Interventions to Improve Somatic rSO2 2,4-5

Interventions to Improve Cardiac Output
  • Cardiac Output = stroke volume x heart rate
  • Preload
  • Afterload
  • Contractility
  • Heart rate and rhythm

Increase Hematocrit
Maintain Normal Temperature

Footnotes:
1. Austin EH 3rd, et al. J Thorac Cardiovasc Surg. 1997 Nov;114(5):707-717.
2. Hoffman GM, Cardiol Young 2005;15(Suppl. 1):149-153.
3. Mott AR, et al. Pediatr Crit Care Med 2006;7:346-350.
4. Han SH, et al. Acta Anaesthesiol Scand. 2004 May;48(5):648-52.
5. Kaufman J, et al. Pediatr Crit Care Med 2008;9(1):62-68.