Effects of Hyperventilation and CO2 Inhalation on Cerebral Oxygen Metabolism of Moyamoya Disease Measured by Near-Infrared Spectroscopy

Purpose: This prospective study was aimed to evaluate the effects of surgical revascularization on cerebral oxygen metabolism in moyamoya disease. Methods: This study included totally 41 patients who underwent STA-MCA anastomosis and indirect bypass for moyamoya disease between 2000 and 2011. There were 12 children and 29 adults. Totally 67 hemispheres underwent surgery. MR imaging and 15O-gas positron emission tomography (PET) were performed before and 3 to 4 months after surgery. Hemodynamic and metabolic parameters were precisely quantified. Results: Preoperative PET scans revealed that cerebral metabolic rate for oxygen (CMRO2) was kept normal in 15 hemispheres (22%), but decreased in other 52 (78%). The incidence did not differ between pediatric and adult patients. Pronounced cerebral ischemia was observed in all hemispheres with decreased CMRO2. After surgery, CMRO2 value significantly improved to the normal level in 20 (38%) of 52 hemispheres, but did not change in other 32 (62%). Multivariate analysis showed that the predictors for postoperative CMRO2 normalization were patient’s age (younger than 40 years) and no parenchymal damage on MRI. Conclusion: These findings strongly suggest that cerebral oxygen metabolism is often depressed in response to dense and chronic cerebral ischemia in moyamoya disease. The phenomenon may be advantageous to protect the involved hemispheres against ischemia. Surgical revascularization may readily normalize oxygen metabolism in young patients without any parenchymal damage.

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Near Infrared Spectroscopy Based Clinical Algorithm Applicability During Spinal Neurosurgery and Postoperative Cognitive Disturbances

Medicina ◽

10.3390/medicina55050179 ◽

2019 ◽

Vol 55 (5) ◽

pp. 179 ◽

Cited By ~ 1

Author(s):

Sniedze Murniece ◽

Martin Soehle ◽

Indulis Vanags ◽

Biruta Mamaja

Keyword(s):

Infrared Spectroscopy ◽

Oxygen Saturation ◽

Near Infrared Spectroscopy ◽

Spinal Surgery ◽

Near Infrared ◽

Control Group ◽

Study Group ◽

Cerebral Oxygen ◽

Clinical Algorithm ◽

Cognitive Disturbances

Background and Objectives: Postoperative cognitive disturbances (POCD) can significantly alter postoperative recovery. Inadequate intraoperative cerebral oxygen supply is one of the inciting causes of POCD. Near-infrared spectroscopy (NIRS) devices monitor cerebral oxygen saturation continuously and can help to guide intraoperative patient management. The aim of the study was to evaluate the applicability of the NIRS-based clinical algorithm during spinal neurosurgery and to find out whether it can influence postoperative cognitive performance. Materials and Methods: Thirty four patients scheduled for spinal neurosurgery were randomized into a study group (n = 23) and a control group (n = 11). We monitored regional cerebral oxygen saturation (rScO2) throughout surgery, using a NIRS device (INVOS 4100). If rScO2 dropped bilaterally or unilaterally by more than 20% from baseline values, or under an absolute value of 50%, the NIRS-based algorithm was initiated in the study group. In the control group, rScO2 was monitored blindly. To evaluate cognitive function, Montreal-Cognitive Assessment (MoCA) scale was used in both groups before and after the surgery. Results: In the study group, rScO2 dropped below the threshold in three patients and the NIRS-based algorithm was activated. Firstly, we verified correct positioning of the head; secondly, we increased mean systemic arterial pressure in the three patients by injecting repeated intravenous bolus doses of Ephedrine, ultimately resulting in an rScO2 increase above the approved threshold level. None of the three patients showed POCD. In the control group, one patient showed a drop in rScO2 of 34% from baseline and presented with a POCD. RScO2 drop occurred with other stable intraoperative measurements. Conclusions: A significant rScO2 drop may occur during spinal surgery in prone position despite other intraoperative measurements remaining stable, allowing it to stay otherwise unrecognized. Use of the NIRS-based clinical algorithm can help to avoid POCD in patients after spinal surgery.

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