[Noninvasive monitoring of regional cerebral oxygen saturation--experiences in critical care medicine]

[Cerebral near infrared spectroscopy and acupuncture--results of a pilot study]

For the first time, we have studied the effects of manual acupuncture and of laser puncture on cerebral oxygenation in three healthy male volunteers using transcranial near-infrared spectroscopy (NIRO 300, Hamamatsu Photonics, Japan). The results indicate that acupuncture of specific acupuncture points leads to an increase in oxygenated haemoglobin and in the tissue oxygenation index. However, needling and laser puncture at placebo points does not produce the same effect on cerebral oxygenation. This fact provides further proof of specific quantifiable effects of acupuncture on the brain.

The influence of positioning on spectroscopic measurements of brain oxygenation

This study was designed to evaluate the influence of body position during neurosurgical and cerebrovascular operations on regional cerebral oxygen saturation (rSO2). Awake volunteers (group I; n = 14), anesthetized patients (group II; n = 48) undergoing lumbar discectomy, and 12 patients undergoing carotid endarterectomy (group III) with internal carotid artery (ICA) stenosis were studied. Anesthesia in the patient groups was performed with sevoflurane (1.1 Vol% insp.) in N2O2/O2 mixture (FiO2 0.4) rSO2 was monitored with a INVOS 4100 cerebral oxymeter (Somanetics Corporation, Troy, MI). Measurements were done in all groups in supine position with head turned to the right and left side. Furthermore, in groups I and II, rSO2 was measured in right lateral, left lateral, prone, or sitting position. In each position the parameters were registered at three times (1, 3, and 5 min after taking up the position). In the healthy volunteers, the mean rSO2 values of both hemispheres were 71.3 +/- 5.0%. No significant changes of rSO2 were found interhemispherical and upon turning the head to both sides or positioning to the prone and both lateral positions. After assuming the sitting position, the decrease of rSO2 was not significant. In group II, rSO2 decreased significantly in the sitting position. In group III, baseline readings for rSO2 obtained from the side of ICA stenosis were significantly lower, compared to the contralateral side. After turning the head to the ipsilateral side, this difference diminished. In contrast, turning the head toward the contralateral side, the rSO2 difference remained nearly constant, both values decreasing constantly throughout the observation period. In conclusion, after different positioning maneuvers awake and under anesthesia, alterations of rSO2 can be registrated by near-infrared spectroscopy (NIRS).