TY - JOUR
T1 - The influence of carbon dioxide and body position on near-infrared spectroscopic assessment of cerebral hemoglobin oxygen saturation
AU - Pollard, Valerie
AU - Prough, Donald S.
AU - Eric DeMelo, A.
AU - Deyo, Donald
AU - Uchida, Tatsuo
AU - Widman, Ron
PY - 1996
Y1 - 1996
N2 - Near-infrared spectroscopy may allow continuous and noninvasive monitoring of regional brain hemoglobin oxygen saturation by measuring the differential absorption of infrared light by oxyhemoglobin and deoxyhemoglobin. We have previously examined the correlation between the spectroscopic signal generated by a prototype cerebral oximeter (Invos 3100®; Somanetics, Troy, MI), and global brain hemoglobin oxygen saturation calculated from arterial and jugular venous bulb oxygen saturations. Because the technology does not distinguish between arterial and venous hemoglobin saturation, changes in the proportion of cerebral arterial and venous blood volume, which may result from changes in blood flow or venous distending pressure, may confound measurements. In eight conscious volunteers breathing hypoxic oxygen mixtures, we examined the influence of supine, 20° Trendeleburg, and 20° reverse Trendelenburg positions on the correlation of the spectroscopic measurement of cerebral oxygen saturation in the field assessed by the probe (CS(f)O 2) and the calculated brain hemoglobin oxygen saturation (CS(comb)O 2), estimated as 0.25 x arterial saturation plus 0.75 x jugular venous bulb oxygen saturation. We found that changes in position did not influence the association between CS(f)O 2 and CS(comb)O 2 (r 2 =0.69-0.885) during hypoxic challenge. In a second set of eight volunteers, we studied the influence of hypercapnia and hypocapnia and body position on the association between CS(f)O 2 and CS(comb)O 2, and found that they were less well correlated (r 2 = 0.366-0.976) in individual patients. Because changes in body position and PaCO 2 confound the relationship between CS(f)O 2 and CS(comb)O 2, changes in CS(f)O 2 can best be assessed if position and PaCO 2 are constant.
AB - Near-infrared spectroscopy may allow continuous and noninvasive monitoring of regional brain hemoglobin oxygen saturation by measuring the differential absorption of infrared light by oxyhemoglobin and deoxyhemoglobin. We have previously examined the correlation between the spectroscopic signal generated by a prototype cerebral oximeter (Invos 3100®; Somanetics, Troy, MI), and global brain hemoglobin oxygen saturation calculated from arterial and jugular venous bulb oxygen saturations. Because the technology does not distinguish between arterial and venous hemoglobin saturation, changes in the proportion of cerebral arterial and venous blood volume, which may result from changes in blood flow or venous distending pressure, may confound measurements. In eight conscious volunteers breathing hypoxic oxygen mixtures, we examined the influence of supine, 20° Trendeleburg, and 20° reverse Trendelenburg positions on the correlation of the spectroscopic measurement of cerebral oxygen saturation in the field assessed by the probe (CS(f)O 2) and the calculated brain hemoglobin oxygen saturation (CS(comb)O 2), estimated as 0.25 x arterial saturation plus 0.75 x jugular venous bulb oxygen saturation. We found that changes in position did not influence the association between CS(f)O 2 and CS(comb)O 2 (r 2 =0.69-0.885) during hypoxic challenge. In a second set of eight volunteers, we studied the influence of hypercapnia and hypocapnia and body position on the association between CS(f)O 2 and CS(comb)O 2, and found that they were less well correlated (r 2 = 0.366-0.976) in individual patients. Because changes in body position and PaCO 2 confound the relationship between CS(f)O 2 and CS(comb)O 2, changes in CS(f)O 2 can best be assessed if position and PaCO 2 are constant.
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U2 - 10.1097/00000539-199602000-00011
DO - 10.1097/00000539-199602000-00011
M3 - Article
C2 - 8561327
AN - SCOPUS:0030019817
SN - 0003-2999
VL - 82
SP - 278
EP - 287
JO - Anesthesia and analgesia
JF - Anesthesia and analgesia
IS - 2
ER -