Early Detection and Correction of Cerebral Desaturation With Noninvasive Oxy-Hemoglobin, Deoxy-Hemoglobin, and Total Hemoglobin in Cardiac Surgery: A Case Series

Abstract

Regional cerebral oxygen saturation (rSo 2 ) obtained from near-infrared spectroscopy (NIRS) provides valuable information during cardiac surgery. The rSo 2 is calculated from the proportion of oxygenated to total hemoglobin in the cerebral vasculature. Root O3 cerebral oximetry (Masimo) allows for individual identification of changes in total (ΔcHbi), oxygenated (Δo 2 Hbi), and deoxygenated (ΔHHbi) hemoglobin spectral absorptions. Variations in these parameters from baseline help identify the underlying mechanisms of cerebral desaturation. This case series represents the first preliminary description of Δo 2 Hbi, ΔHHbi, and ΔcHbi variations in 10 cardiac surgical settings. Hemoglobin spectral absorption changes can be classified according to 3 distinct variations of cerebral desaturation. Reduced cerebral oxygen content or increased cerebral metabolism without major blood flow changes is reflected by decreased Δo 2 Hbi, unchanged ΔcHbi, and increased ΔHHbi Reduced cerebral arterial blood flow is suggested by decreased Δo 2 Hbi and ΔcHbi, with variable ΔHHbi. Finally, acute cerebral congestion may be suspected with increased ΔHHbi and ΔcHbi with unchanged Δo 2 Hbi. Cerebral desaturation can also result from mixed mechanisms reflected by variable combination of those 3 patterns. Normal cerebral saturation can occur, where reduced cerebral oxygen content such as anemia is balanced by a reduction in cerebral oxygen consumption such as during hypothermia. A summative algorithm using rSo 2 , Δo 2 Hbi, ΔHHbi, and ΔcHbi is proposed. Further explorations involving more patients should be performed to establish the potential role and limitations of monitoring hemoglobin spectral absorption signals. (Anesth Analg 2022;135:1304-14) GLOSSARY ΔcHbi = index representing changes in the total (ΔHHbi + Δo 2 Hbi) hemoglobin component of the rSo 2 ; ΔHHbi = index representing changes in the deoxygenated hemoglobin component of the rSo 2 ; Δo 2 Hbi = index representing changes in the oxygenated hemoglobin component of the rSo 2 ; Cao 2 = arterial oxygen content; CBF = cerebral blood flow; CMRo 2 = cerebral metabolic rate of oxygen; COVID-19 = coronavirus disease 2019; CPB = cardiopulmonary bypass; dP/dT = change in the pressure over time ratio; HITS = high-intensity transient signal; IT = intratracheal; LE = lower extremity; LV = left ventricular; LVEF = left ventricular ejection fraction; NIRS = near-infrared spectroscopy; pEEG = processed electroencephalography; Pfa = femoral artery pressure; Ppa = pulmonary artery pressure; Pra = radial arterial pressure; Prv = right ventricular pressure; rSo 2 = regional oxygen saturation; RV = right ventricular; SVC = superior vena cava; TCD = transcranial Doppler; UE = upper extremity

Longitudinal Validation of Right Ventricular Pressure Monitoring for the Assessment of Right Ventricular Systolic Dysfunction in a Large Animal Ischemic Model

“…Those will help in determining how sensitive changes in dP/dt are in detecting abnormal RV dysfunction. We have, however, reported that increases in dP/dt were clearly associated with improvement in RV function ( 32 , 47 , 48 )…”

“…Those will help in determining how sensitive changes in dP/dt are in detecting abnormal RV dysfunction. We have, however, reported that increases in dP/dt were clearly associated with improvement in RV function (32,47,48) Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://journals.lww.com/ccejournal).…”

Non-invasive technology for brain monitoring: definition and meaning of the principal parameters for the International PRactice On TEChnology neuro-moniToring group (I-PROTECT)

“…Cerebral (frontal cortex) rSO 2 is a global indicator of cerebral perfusion that reflects the balance between oxygen delivery and consumption. The measurement of cerebral Hb-oxygen saturation by means of NIRS is associated with important clinical outcomes [28] as it represents the proportion of O 2 Hb to tHb in the cerebral vasculature. Many clinical conditions such as hypotension and/or hypoperfusion, ischemia (caused by embolism), compression, or impairment of venous drainage may affect cerebral oxygenation, and in most of these situations, arterial Hb oxygen saturation (SaO 2 ) may remain within the normal limits.…”

“…Many clinical conditions such as hypotension and/or hypoperfusion, ischemia (caused by embolism), compression, or impairment of venous drainage may affect cerebral oxygenation, and in most of these situations, arterial Hb oxygen saturation (SaO 2 ) may remain within the normal limits. By examining rSO 2 and its sub-components (O 2 Hb, HHb, and tHb), the clinician can identify episodes of cerebral desaturation and intervene according to algorithms that have shown to successfully help improve cerebral oxygenation [28][29][30]. anterior cerebral artery (ACA), posterior cerebral artery (PCA), and communicating arteries (Fig.…”

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“…Altogether, due to its non-invasive, continuous and easy to use character, cerebral oximetry alone may provide important information regarding tissue oxygenation in major surgery and in highrisk patients, especially when combined with a depth-of-anesthesia monitor 45 . Nevertheless, one should keep in mind that NIRS is a trend monitor and will not provide absolute tissue oxygenation values 2 .…”