The bispectral index (BIS) has been developed as a measure for monitoring the hypnotic drug effect. EEG processing results in a BIS scale from 0 to 100, where 100 represents an awake and responsive patient, and the scale decreases when hypnotics are administered. Here we describe two patients in whom the BIS decreased to nearly 0 during cardiac surgery. Postoperatively both patients showed hypoxic brain injury. There are several possible causes for a decrease in the BIS during surgery, including deep anesthesia, hypothermia and cerebral ischemia. In the present cases, cerebral hypoperfusion was the likely cause. During cardiac surgery, hemodynamic changes such as acute hypotension and cardiac arrest can cause cerebral ischemia. Cerebral ischemia develops most commonly during cardiopulmonary bypass (CPB). Therefore, the BIS may be useful for detecting severe cerebral ischemia during CPB, although it has some limitations as a cerebral monitor.
Anesthesia ; Brain Injuries ; Brain Ischemia* ; Cardiopulmonary Bypass* ; Electroencephalography ; Heart Arrest ; Hemodynamics ; Humans ; Hypnotics and Sedatives ; Hypotension ; Hypothermia ; Thoracic Surgery

BACKGROUND AND OBJECTIVES: Proficient differentiation of human pluripotent stem cells (hPSCs) into specific lineages is required for applications in regenerative medicine. A growing amount of evidences had implicated hormones and hormone-like molecules as critical regulators of proliferation and lineage specification during in vivo development. Therefore, a deeper understanding of the hormones and hormone-like molecules involved in cell fate decisions is critical for efficient and controlled differentiation of hPSCs into specific lineages. Thus, we functionally and quantitatively compared the effects of diverse hormones (estradiol 17-β (E2), progesterone (P4), and dexamethasone (DM)) and a hormone-like molecule (retinoic acid (RA)) on the regulation of hematopoietic and neural lineage specification. METHODS AND RESULTS: We used 10 nM E2, 3 μM P4, 10 nM DM, and 10 nM RA based on their functional in vivo developmental potential. The sex hormone E2 enhanced functional activity of hematopoietic progenitors compared to P4 and DM, whereas RA impaired hematopoietic differentiation. In addition, E2 increased CD34⁺CD45⁺ cells with progenitor functions, even in the CD43⁻ population, a well-known hemogenic marker. RA exhibited lineage-biased potential, preferentially committing hPSCs toward the neural lineage while restricting the hematopoietic fate decision. CONCLUSIONS: Our findings reveal unique cell fate potentials of E2 and RA treatment and provide valuable differentiation information that is essential for hPSC applications.
Dexamethasone ; Humans ; Induced Pluripotent Stem Cells ; Pluripotent Stem Cells ; Progesterone ; Regenerative Medicine ; Tretinoin