Background: Tissue(cerebral/somatic)oxygenation monitoring by Near Infrared Spectroscopy(NIRS)is a noninvasive and easy implementation tool, recommended in cardiopulmonary surgery. This monitoring has shown an impaired cerebrovascular autoregulation in premature neonates, and can help to improve neurologic outcome after cardiac surgery. We describe the information from the NIRS during anesthesia for neonatal non-cardiac surgery.
Materials and Methods: 61 infants aged 39±5 weeks corrected age were included prospectively. Standard parameters and tissue saturations(INVOS-Oximeter, Somanetics)were collected before and during anesthesia. Desaturations tissue (-20% of baseline), the arterial hypotension (-30% of baseline) and systemic desaturation (SpO2< 90%) were compiled.
Results: 44% (27/61) of patients experienced at least one cerebral desaturation (-35±14%) and 44% at least one somatic desaturation(-37±14 %). 33%(20/61)of patients had multiple episodes. The cerebral and somatic desaturations were concurrent in 21%(13/61)of patients. Events associated with desaturations tissue are design in table 1.
Factors favoring the occurrence of desaturations tissue associated with hypotension are shown in table 2 and 3.
70% of patients who experienced an episode of simultaneous cerebral and somatic desaturation concurrent with low blood pressure had a Hb < 12 g/dl.
Conclusion: Tissue desaturations are common in neonatal anesthesia, most commonly associated with respiratory or hemodynamic incident. The depth of hypotension doesn't seem to be associated with the occurrence of desaturations tissue. The decrease in hemoglobin, low birth weight and a history of extreme prematurity could favor the occurrence of simultaneously cerebral and somatic desaturations, during a hypotensive episode. Intraoperative monitoring of tissue oxygenation for newborns would identify those at risk and allow for rapid action to reduce the tissue damage.