Clinical evaluation of time-resolved spectroscopy by measuring cerebral hemodynamics during cardiopulmonary bypass surgery

Abstract

We developed a three-wavelength time-resolved spectroscopy (TRS) system, which allows quantitative measurement of hemodynamics within relatively large living tissue. We clinically evaluated this TRS system by monitoring cerebral circulation during cardiopulmonary bypass surgery. Oxyhemoglobin, deoxyhemoglobin, total hemoglobin and oxygen saturation (SO(2)) were determined by TRS on the left forehead attached with an optode spacing of 4 cm. We also simultaneously monitored jugular venous oxygen saturation (SjvO(2)) and arterial blood hematocrit (Hct) using conventional methods. The validity and usefulness of the TRS system were assessed by comparing parameters obtained with the TRS and conventional methods. Although the changes in SO(2) were lower than those in SjvO(2), SO(2) obtained by TRS paralleled the fluctuations in SjvO(2), and a good correlation between these values was observed. The only exceptions occurred during the perfusion period. Moreover, there was a good correlation between tHb and Hct values (r(2)=0.63). We concluded that time-resolved spectroscopy reflected the conditions of cerebral hemodynamics of patients during surgical operations.

Comparison of the effects of olfactory stimulation by air-dried and high-temperature-dried wood chips of hinoki cypress (Chamaecyparis obtusa) on prefrontal cortex activity

“…; [20][21][22]). The oxy-Hb concentrations in the left and right prefrontal cortex were measured at 1 Hz for 10 s before (premeasurement condition) odor administration as well as during the 90 s of odor administration (postmeasurement condition).…”

Physiological effects of touching hinoki cypress (Chamaecyparis obtusa)

“…Sensors were mounted on the participant's forehead, and oxy-Hb concentrations in the prefrontal cortex were measured by a TRS-20 system (Hamamatsu Photonics K.K., Shizuoka, Japan) [21][22][23]. The oxy-Hb concentrations in the left and right prefrontal cortex were measured before the participant touched the materials (premeasurement) and during the 90 s during which the participant touched the materials (postmeasurement).…”

Comparison of a layered slab and an atlas head model for Monte Carlo fitting of time-domain near-infrared spectroscopy data of the adult head

“…They have been validated with Monte Carlo simulations and phantoms, 15,23,24 and have been applied to monitor developmental cerebral changes in infants. 22 In adults, the TD-NIRS technology has been applied to monitor variations in brain oxygenation and blood volume during cardiopulmonary bypass surgery 25 or to detect vasospasms following subarachnoid hemorrhage. 21 Most of the in vivo studies mentioned above have relied on a simple head model described as a homogeneous semi-infinite medium.…”

“…21 Most of the in vivo studies mentioned above have relied on a simple head model described as a homogeneous semi-infinite medium. 1,[6][7][8][9][10]16,[19][20][21][22]25,26 This model has shown promising results in piglets and infants, 5,8,9,11,20,22,27 but it is widely recognized that, in the case of the adult head, its oversimplification causes strong contamination of the brain optical properties by those of the extracerebral tissue. For the FDMD approach, Franceschini et al 12 have shown, with simulations and phantom measurements in a slab geometry, that when a superficial layer thicker than ∼1 cm is present, the error on the retrieved absorption of the second layer can exceed 50%.…”