Advanced Age and Sex Influence Baseline Regional Cerebral Oxygen Saturation as Measured by Near-Infrared Spectroscopy: Subanalysis of a Prospective Study.

OBJECTIVES

The aging brain shows decreased venous oxygenation predominantly in the frontal cortex, which seems sex- dependent. The authors hypothesized that age and sex would influence baseline regional cerebral oxygen saturation (rScO) measured by the INVOS 5100.

DESIGN

Subanalysis of published data.

SETTING

Tertiary hospital.

PARTICIPANTS

A total of 1,616 adults undergoing cardiac interventions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Baseline rScO was recorded at room air and calculated as mean of the left and right rScO. Patients were divided into 3 groups: 18- to- 49 years: young; 50- to- 74 years: middle-aged; and ≥75 years: elderly. The rScO was significantly different in the middle-aged (63 [56-69]) compared with the young participants (67 [59-74]; p < 0.001) and elderly participants (60 [55-66]; p < 0.001]. Women were significantly older compared with men (72 [62-79] v 66 [56-74]; p < 0.001]) and showed lower hemoglobin values (p < 0.001) and lower rScO (58 [52-63] v 65 [58-70]; p < 0.001]). Multiple regression analysis revealed age, sex, and hemoglobin as significant determinants of rScO: 26.665 - (0.030 × age) + (2.581 × hemoglobin) + (2.799 × 0 for female sex).

CONCLUSIONS

Baseline rScO as measured by the INVOS 5100, decreases with advanced age and is lower in women. New definitions of cerebral oxygen desaturation need to be analyzed in future trials that will evaluate neurologic outcome in the aging population or in women.