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Key Study Findings - Infant/Neonatal

The following Key Study Findings are just a sample of the more than 600 compelling clinical presentations, study abstracts and published papers documenting INVOS® System benefits.

To see the full bibliography, please visit Clinical Evidence.

Stem the Tide of Ischemic Brain Lesions



This observational study compared preoperative and postoperative brain MRI findings in 22 term neonates undergoing Norwood palliation for hypoplastic left heart syndrome (HLHS).
  • Low post-op rSO2 (<45% for >180 minutes) was associated with new or worsened ischemic brain lesions on serial MRIs.
  • This association did not apply to intra-operative factors (e.g.,RLFP or CPB time), nor to traditional post-op measures of overall cardiac output (e.g., SvO2 value, serum lactate level or acid-base status).
  • This suggests that the critical period during which neurological injury occurs or progresses is post-operative, and that the usual post-op clinical measurements to assess global cardiac output might not reflect cerebral perfusion.
  • Maneuvers to improve cerebral perfusion during the post-op period using the INVOS® System might lessen the incidence of ischemic brain lesions.
  • The investigator states, "The ability to detect and improve low cerebral oxygen saturation during the postoperative period may reduce the incidence of postoperative ischemia and subsequent neurologic deficit."

Footnote:
Dent CL, et al. J Thorac Cardiovasc Surg. 2005;130:1523 and Neonatal Intensive Care/The Journal of Perinatology-Neonatology: October 2006; Volume 19, Number 6.

Gain Insights on Autoregulation using rSO2



When ScO2 changes with blood pressure it can be an indication of loss of cerebral autoregulation.

This study examined neonates with and without Respiratory Distress Syndrome (RDS) from birth through 72 hours.

  • RDS infants had a significantly larger range of cerebral oxygenation and cerebral oxygen extraction; suggesting more fluctuations in cerebral perfusion and oxygenation than non-RDS infants.
  • These cerebral parameters also had a significant association with mean arterial blood pressure suggesting impairment of cerebral-vascular autoregulation, p<0.05.
  • Lack of autoregulation may predispose RDS infants to a higher risk of brain damage.

The authors stated that "the findings further underscore the importance of monitoring oxygenation and extraction in the critically ill preterm infant with RDS."

Footnote:
Lemmers PM et al., Exp Brain Res. 2006 Aug;173(3):458-67. Epub 2006 Feb 28.

Manage Hypoxia in Ventilated Patients

Correlation between arterial saturation (SaO2) and cerebral and renal tissue oxygenation (rSO2C and rSO2R). Declines in arterial saturation reflect reduced oxygen delivery to tissue, as witnessed by declines in rSO2.


A study on mechanically-ventilated neonates with a gestational age between 24-32 weeks showed that:
  • Arterial desaturations (SaO2) between 70-80% reduced cerebral and peri-renal rSO2, significantly correlating with the changes in SaO2.
  • None of the other monitored hemodynamic variables demonstrated this relationship during desaturation.
  • Peri-renal rSO2 was impacted more than cerebral and took longer to recover, reflecting the compensatory nature of organs in the periphery and their ability to be an early warning of ischemic complications.

The authors concluded that "NIRS has provided useful information for the management of preterm neonates undergoing critical care."

Footnote:
Petrova A et al., Pediatr Crit Care Med. 2006 Sept;7(5):449-54.
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Monitoring rSO2 Following Birth Asphyxia


This study examined neonates presenting with hypoxic-ischemic encephalopathy from birth to 48 hours, with 5-year developmental follow up.
  • Amplitude-integrated EEG measurements were abnormal throughout the period.
  • rSO2 showed a significant correlation with adverse outcomes (death) 24 hours after birth.
  • From 24 hours onward, the rSO2 values of infants with adverse outcomes were significantly higher than the favorable outcome group whose values were within normal range.
  • These much higher values suggest a decrease in oxygen uptake by dying neuronal cells or asphyxia-induced vasoparalysis.

The authors suggest that "rSO2 can be monitored in a noninvasive, easy and reliable manner over extended periods of time and reflect metabolic disturbances such as secondary energy failure after severe birth asphyxia."

Footnote:
Toet MC et al., Pediatrics. 2006 Feb;117(2):333-9.

See Immediate Results of PDA Ligation on Oxygenation



The INVOS® System was used to monitor cerebral and abdominal regional oximetry in a preterm neonate undergoing surgical ligation of a patent ductus arteriosus (PDA).
  • Upon ligation of the PDA, the abdominal rSO2 increased 112% and remained at this level.
  • Cerebral rSO2 also increased, but not as much (14%).

The investigators note that abnormally low levels of rSO2 may be useful in selecting patients with hemodynamically significant PDAs that warrant medical/surgical intervention. Moreover, low abdominal rSO2 may reflect intestinal ischemia, which if prolonged may lead to necrotizing enterocolitis (NEC).

Footnote:
Meier et al, J Perinatol 2006;26:562-4.