Initial Description of Cerebral Oximetry Measurement in Heart Failure Patients

Abstract

Cerebral oximetry is a noninvasive technology using near-infrared spectroscopy (NIRS) to monitor regional cerebral tissue oxygen saturation (SctO(2)). NIRS has been widely used for assessing cerebral tissue oxygenation in a variety of populations including the fields of neonatology, anesthesiology, neurology, and cardiac surgery.However, little information has been reported on cerebral oximetry in heart failure (HF) patients. In this observational study, we enrolled 30 patients (15 men) aged 23 to 82 years (mean 67 years) with stage C HF. All patients had New York Heart Association (NYHA) functional class I to III. All patients were on stable HF medical therapy. SctO(2) measurements were recorded from the left and right forehead simultaneously, using FORE-SIGHT cerebral oximeter (CAS Medical Systems Inc, Branford, CT). Feasible associations with SctO(2) risk factors, known to correlate with HF, were recorded. The mean SctO(2) value was 67.4% (range, 47.6%-76.3%), while the mean peripheral tissue saturation (SpO(2)) was 97% (range, 92%-100%). The mean difference between cerebral and peripheral tissue oxygenation (SpO(2)-SctO(2)) was 29.2% (range, 19.2%-51.4%). There was also a significant positive correlation between SctO(2) and mean arterial blood pressure (0.55, P<.01). Statistically significant lower SctO(2) values were observed in patients with diabetes (P=.026; confidence interval [CI], 0.006-0.090) and in patients with dyslipidemia (P=.007; CI, 0.018-0.103). In this initial description of SctO(2) in patients with stage C HF, we noted a wide range of SctO(2) measurements. For most patients, there was a profound SpO(2)-SctO(2) difference, despite near-normal peripheral oxygen saturations. The authors suggest that SctO(2) is a potentially important biomarker to measure in HF patients and may be a useful marker of target organ perfusion.

Brainstem Hypoxia Contributes to the Development of Hypertension in the Spontaneously Hypertensive Rat

“…43 Interestingly, a recent study using cerebral oximetry has demonstrated that cerebral tissue oxygen saturation in many heart failure patients is low, despite nearly normal levels measured in the arterial blood. 47 It seems that the same mechanism activated by brainstem hypoxia might be responsible for heightened central sympathetic tone in both heart failure and systemic arterial hypertension.…”

Influence of Ventilation Strategies and Anesthetic Techniques on Regional Cerebral Oximetry in the Beach Chair Position

“…Diastolic blood pressure shows positive correlation, approximately 1-2% per 10mmHg, with cerebral oximetry in congestive heart failure. 40 It is possible that a similar relationship exists in patients without heart failure or those in the beach chair position, but this has not been determined.…”

The Accuracy of a Near-Infrared Spectroscopy Cerebral Oximetry Device and Its Potential Value for Estimating Jugular Venous Oxygen Saturation

“…27,28,29 The significance of the cerebral oximeter can be further demonstrated by substituting equation 3 (assuming blood distribution to be 70% venous (Kv = 0.7), 30% arterial (Ka = 0.3), and negligible amount in the capillaries (Kc = 0) and ERROR assumed to be zero for the ideal case as suggested by Ito et al 11 ) into equation 6 and solving the ratio of CMRO 2 to CBF as a function of S ct O 2 (equation 7). $$\mathrm{normalC}\mathrm{normalM}\mathrm{normalR}{\mathrm{O}}_2/\mathrm{normalC}\mathrm{normalB}\mathrm{normalF}=false({\mathrm{S}}_{\mathrm{p}}{\mathrm{O}}_2-{\mathrm{S}}_{\mathrm{normalc}\mathrm{normalt}}{\mathrm{O}}_{2}false)\times \mathrm{normalK}1+\mathrm{normalK}2$$

Where K1 = (1.34 × [tHb]) /0.7

And

K2 = 0.003 × (P a O 2 − P jb O 2 ).

Solving equation 7 for S ct O 2 then becomes (equation 8): $${\mathrm{S}}_{\mathrm{normalc}\mathrm{normalt}}{\mathrm{O}}_2={\mathrm{S}}_{\mathrm{p}}{\mathrm{O}}_2+false(\mathrm{normalK}2-\mathrm{normalC}\mathrm{normalM}\mathrm{normalR}{\mathrm{O}}_2/\mathrm{normalC}\mathrm{normalB}\mathrm{normalF}false)/\mathrm{normalK}1$$ From this equation, it can be deduced that the S ct O 2 has a proportional relationship to S p O 2 and CMRO 2 and inversely proportional with CBF.…”