Purpose Continuous measurement of aortic pressure and aortic flow velocity signals in the operating theatre allows us to draw velocity-pressure (Vel-Pre) loops. The global afterload angle (GALA), derived from the Vel-Pre loops, has been linked to cardiac afterload indicators. As age is the major determinant of constitutive arterial stiffness, we aimed to describe (1) the evolution of the GALA according to age in a large cohort of anesthetized patients and (2) GALA variations induced by haemodynamic interventions. Methods We included patients for whom continuous monitoring of arterial pressure and cardiac output were indicated. Fluid challenges or vasopressors were administered to treat intra-operative hypotension. The primary endpoint was the comparison of the GALA values between young and old patients. The secondary endpoint was the difference in the GALA values before and after haemodynamic interventions. Results We included 133 anaesthetized patients: 66 old and 67 young patients. At baseline, the GALA was higher in the old patients than in young patients (38 ± 6 vs. 25 ± 4 degrees; p < 0.001). The GALA was positively associated with age (p < 0.001), but the mean arterial pressure (MAP) and cardiac output were not. The GALA did not change after volume expansion, regardless of the fluid response, but it did increase after vasopressor administration. Furthermore, while a vasopressor bolus led to a similar increase in MAP, phenylephrine induced a more substantial increase in the GALA than noradrenaline (+ 12 ± 5° vs. + 8 ± 5°; p = 0.01). Conclusion In non-cardiac surgery, the GALA seems to be associated with both intrinsic rigidity (reflected by age) and pharmacologically induced vasoconstriction changes (by vasopressors). In addition, the GALA can discriminate the differential effects of phenylephrine and noradrenaline. These results should be confirmed in a prospective, ideally randomized, trial.

Cardiac afterload is usually assessed in the ascending aorta and can be defined by the association of peripheral vascular resistance (PVR), total arterial compliance (Ctot), and aortic wave reflection (WR). We recently proposed the global afterload angle (GALA) and β-angle derived from the aortic velocity-pressure (VP) loop as continuous cardiac afterload monitoring in the descending thoracic aorta. The aim of this study was to 1) describe the arterial mechanic properties by studying the velocity-pressure relations according to cardiovascular risk (low-risk and high-risk patients) in the ascending and descending thoracic aorta and 2) analyze the association between the VP loop (GALA and β-angle) and cardiac afterload parameters (PVR, Ctot, and WR). PVR, Ctot, WR, and VP loop parameters were measured in the ascending and descending thoracic aorta in 50 anesthetized patients. At each aortic level, the mean arterial pressure (MAP), cardiac output (CO), and PVR were similar between low-risk and high-risk patients. In contrast, Ctot, WR, GALA, and β-angle were strongly influenced by cardiovascular risk factors regardless of the site of measurement along the aorta. The GALA angle was inversely related to aortic compliance, and the β-angle reflected the magnitude of wave reflection in both the ascending and descending aortas (P < 0.001). Under general anesthesia, the VP loop can provide new visual insights into arterial mechanical properties compared with the traditional MAP and CO for the assessment of cardiac afterload. Further studies are necessary to demonstrate the clinical utility of the VP loop in the operating room.NEW & NOTEWORTHY Our team recently proposed the global afterload angle (GALA) and β-angle derived from the aortic velocity-pressure (VP) loop as continuous cardiac afterload monitoring in the descending thoracic aorta under general anesthesia. However, the evaluation of cardiac afterload at this location is unusual. The present study shows that VP loop parameters can describe the components of cardiac afterload both in the ascending and descending thoracic aorta in the operating room. Aging and cardiovascular risk factors strongly influence VP loop parameters. The VP loop could provide continuous visual additional information on the arterial system than the traditional mean arterial pressure and cardiac output during the general anesthesia.

Introduction: Pressure-Velocity (PU) loops obtained in the descending thoracic aorta (PU-loopsdes) could estimate left ventricular afterload with two remarkable angles: β and GALA (Global Afterload Angle) [1].The aim of this study is to compare PU-loops measured in the ascending aorta (PU-loopsasc) versus PU-loopsdes. Methods: This study was conducted in patients scheduled for elective interventional neuroradiology. During the procedure, we measured pressures at two different sites:(1) in the ascending aorta where we obtained a transthoracic echocardiogram (TEE) concomitantly to measure ascending aortic blood velocity, (2) in the descending thoracic aorta where blood velocity was obtained using a trans-esophageal Doppler probe. Patients were divided into high risk (HR) and low risk (LR) groups based on their cardiovascular risk factors. Results: Twenty five patients were included (13 HR, 12 LR). We observed a significant increase in both β and GALA angles between PU-loopsasc and PU-loopsdes (from 7° [0–15] to 13° [5–20] and from 30° [23–37] to 41° [29–54], p < 0.01 respectively). This increase was more marked in the HR group compared to the LR group (p < 0.05) (Fig 1). Just like in PU-loopsdes, we found that β and GALA angles in PU-loopsasc could also discriminate between LR and HR patients (3° [0.4–6] vs 17° [9–25] and 24° [22–26] vs 38° [34–43], p < 0.01 respectively). Conclusion: PU-loopsasc had lower β and GALA angles compared to PU-loopsdes. However, GALA could discriminate between high and low cardiovascular risk patients in both sites.

Objective: Under General Anesthesia (GA), age and Burst Suppression (BS) are associated with cognitive postoperative complications, yet how these parameters are related to per-operative EEG and hypnotic doses is unclear. In this prospective study, we address this question comparing age and BS occurrences with a new score (BPTIVA) based on Propofol doses, EEG and alpha-band power spectral densities, evaluated for SEF95 = 8-13 Hz. Methods: 59 patients (55 [34-67] yr, 67% female) undergoing neuroradiology or orthopedic surgery were included. Total IntraVenous Anesthesia was used for Propofol and analgesics infusion. Cerebral activity was monitored from a frontal electrodes montage EEG. Results: BPTIVA was inversely correlated with age (Pearson r = -0.78, p < 0.001), and was significantly lower (p < 0.001) when BS occurred during the GA first minutes (induction). Additionally, the age-free BPTIVA score was better associated with BS at induction than age (AUC = 0.94 versus 0.82, p < 0.05). Conclusion: We designed BPTIVA score based on hypnotics and EEG. It was correlated with age yet was better associated to BS occurring during GA induction, the latter being a cerebral fragility sign. Significance: This advocate for an approach based on evaluating the cerebral physiological age ("brain age") to predict postoperative cognitive evolution. (C) 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.