Neuroprotection Strategies in Aortic Surgery

Association of intraoperative blood gas analysis with patient outcome after adult cardiac surgery

“…[19,20,24] Since the aim of alpha-stat is to keep a nontemperature corrected pH of 7.4 and a PCO 2 of 40 mmHg irrespective of a patient's actual body temperature, this technique conserves the ionization of the imidazole groups on intracellular proteins and maintain intracellular electrochemical neutrality, buffering, and enzymatic function. [25] It might be expected to preserve enzyme function, protein structure and function, net membrane charge, transport characteristics, [26] thereby contributing to the protection of organ function. The standard normal pH ranges from 7.35 to 7.45 and values outside of this range are considered abnormal.…”

Neuroprotective Strategies in Repair and Replacement of the Aortic Arch

“…Given the degree of molecular activity that occurs during ischemia, pharmacologic intervention has generated substantial interest as a therapeutic avenue, 13,14 and many drugs that may protect against residual neuronal activity and reduce oxygen consumption have been trialed, especially as an adjunctive measure to hypothermia. Early work considered the possibility of barbiturates, 15 which showed promise in animal models by reducing excitotoxic damage but has produced conflicting evidence in man.…”

“…Ultimately, this produces pressure-dependent cerebral perfusion, hyperemia, and edema. 6,153 While controversy persists and complex pH monitoring strategies exist, such as using pH-stat during periods of circulatory arrest to improve perfusion of deep brain structures while using α-stat management otherwise, 14 consensus [154][155][156] generally favors α-stat management during adult cardiac surgeries for reasons including reduced postoperative acidosis, 157 improved metabolic suppression, 158 and improved cognitive function, 159 though pH-stat monitoring continues to be favored for pediatric operations. 160,161 Debates and Unknowns…”

Cerebral Electrical Impedance Tomography: Background Noise or an Important Signal in Cerebral Monitoring in Aortic Arch Surgery?

“…1 Additional perfusion strategies to allow perfusion of the brain, such as selective anterograde, bilateral anterograde, or retrograde cerebral perfusion, have become common methods for cerebral protection at many institutions. 2 Despite these perfusion strategies, transient neurologic dysfunction still occurs in as high as 30% of patients and permanent stroke in 8% of patients during aortic arch surgery. 3,4 Ideally, a real-time cerebral monitor would detect ischemia rapidly with high sensitivity and specificity, be easy to apply and interpret in a busy operating room, and give precise information to help clinical decision-making.…”

“…Currently, clinicians use transcranial Doppler, jugular bulb venous oxygen saturation, near-infrared spectroscopy, somatosensory evoked potentials, and electroencephalogram to monitor the brain during arch surgery. 2 However, each technique has limitations. Transcranial Doppler is technically challenging and only examines large vessel perfusion.…”