Dynamic Cerebral Autoregulation after Cardiopulmonary Bypass

Abstract

Background Cerebral hemodynamic disturbances in the peri- or postoperative period may contribute to postoperative cognitive dysfunction (POCD) in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). We therefore examined dynamic cerebral autoregulation (dCA) post-CPB and changes in neurocognitive function in patients that had undergone CABG.

Materials and Methods We assessed dCA by transfer function analysis of spontaneous oscillations between arterial blood pressure and middle cerebral artery blood flow velocity measured by transcranial Doppler ultrasound in eight patients 6 hours after the cessation of CPB; 10 healthy volunteers served as controls. Neurocognitive function was assessed by four specific tests 1 day prior to and 3 days after CPB.

Results Even though patients exhibited systemic inflammation and anemic hypoxemia, dCA was similar to healthy volunteers (gain: 1.24 [0.94–1.49] vs. 1.22 [1.06–1.34] cm mm Hg⁻¹ s⁻¹, p = 0.97; phase: 0.33 [0.15–0.56] vs. 0.69 [0.50–0.77] rad, p = 0.09). Neurocognitive testing showed a perioperative decline in the Letter Digit Coding Score (p = 0.04), while weaker dCA was associated with a lower Stroop Color Word Test (rho =  − 0.90; p = 0.01).

Discussion and Conclusion We found no changes in dCA 6 hours after CPB. However, based on the data at hand, it cannot be ruled out that changes in dCA predispose to POCD, which calls for larger studies that assess the potential impact of dCA in the early postoperative period on POCD.

Keywords

cerebral autoregulation - cardiopulmonary bypass - postoperative cognitive dysfunction

• References

• 1 Ono M, Brady K, Easley RB , et al. Duration and magnitude of blood pressure below cerebral autoregulation threshold during cardiopulmonary bypass is associated with major morbidity and operative mortality. J Thorac Cardiovasc Surg 2014; 147 (1) 483-489
• 2 Zhang R, Zuckerman JH, Giller CA, Levine BD. Transfer function analysis of dynamic cerebral autoregulation in humans. Am J Physiol 1998; 274 (1, Pt 2) H233-H241
• 3 Brady K, Joshi B, Zweifel C , et al. Real-time continuous monitoring of cerebral blood flow autoregulation using near-infrared spectroscopy in patients undergoing cardiopulmonary bypass. Stroke 2010; 41 (9) 1951-1956
• 4 Ono M, Joshi B, Brady K , et al. Risks for impaired cerebral autoregulation during cardiopulmonary bypass and postoperative stroke. Br J Anaesth 2012; 109 (3) 391-398
• 5 Preisman S, Marks R, Nahtomi-Shick O, Sidi A. Preservation of static and dynamic cerebral autoregulation after mild hypothermic cardiopulmonary bypass. Br J Anaesth 2005; 95 (2) 207-211
• 6 van Harten AE, Scheeren TW, Absalom AR. A review of postoperative cognitive dysfunction and neuroinflammation associated with cardiac surgery and anaesthesia. Anaesthesia 2012; 67 (3) 280-293
• 7 Nandate K, Vuylsteke A, Crosbie AE, Messahel S, Oduro-Dominah A, Menon DK. Cerebrovascular cytokine responses during coronary artery bypass surgery: specific production of interleukin-8 and its attenuation by hypothermic cardiopulmonary bypass. Anesth Analg 1999; 89 (4) 823-828
• 8 Berg RMG, Plovsing RR, Evans KA , et al. Lipopolysaccharide infusion enhances dynamic cerebral autoregulation without affecting cerebral oxygen vasoreactivity in healthy volunteers. Crit Care 2013; 17 (5) R238
• 9 Bishop CC, Powell S, Rutt D, Browse NL. Transcranial Doppler measurement of middle cerebral artery blood flow velocity: a validation study. Stroke 1986; 17 (5) 913-915
• 10 Willie CK, Colino FL, Bailey DM , et al. Utility of transcranial Doppler ultrasound for the integrative assessment of cerebrovascular function. J Neurosci Methods 2011; 196 (2) 221-237
• 11 Murkin JM, Newman SP, Stump DA, Blumenthal JA. Statement of consensus on assessment of neurobehavioral outcomes after cardiac surgery. Ann Thorac Surg 1995; 59 (5) 1289-1295
• 12 Rasmussen LS, Larsen K, Houx P, Skovgaard LT, Hanning CD, Moller JT ; ISPOCD group. The International Study of Postoperative Cognitive Dysfunction. The assessment of postoperative cognitive function. Acta Anaesthesiol Scand 2001; 45 (3) 275-289
• 13 Moller JT, Cluitmans P, Rasmussen LS , et al; International Study of Post-Operative Cognitive Dysfunction. Long-term postoperative cognitive dysfunction in the elderly ISPOCD1 study. ISPOCD investigators. Lancet 1998; 351 (9106) 857-861
• 14 Berg RMG, Plovsing RR, Ronit A, Bailey DM, Holstein-Rathlou NH, Møller K. Disassociation of static and dynamic cerebral autoregulatory performance in healthy volunteers after lipopolysaccharide infusion and in patients with sepsis. Am J Physiol Regul Integr Comp Physiol 2012; 303 (11) R1127-R1135
• 15 Berg RMG, Plovsing RR, Bailey DM, Holstein-Rathlou NH, Møller K. Dynamic cerebral autoregulation to induced blood pressure changes in human experimental and clinical sepsis. Clin Physiol Funct Imaging 2015; , in press
• 16 Brassard P, Kim YS, van Lieshout J, Secher NH, Rosenmeier JB. Endotoxemia reduces cerebral perfusion but enhances dynamic cerebrovascular autoregulation at reduced arterial carbon dioxide tension. Crit Care Med 2012; 40 (6) 1873-1878
• 17 van Beek AH, Claassen JA, Rikkert MG, Jansen RW. Cerebral autoregulation: an overview of current concepts and methodology with special focus on the elderly. J Cereb Blood Flow Metab 2008; 28 (6) 1071-1085
• 18 Horsfield MA, Jara JL, Saeed NP, Panerai RB, Robinson TG. Regional differences in dynamic cerebral autoregulation in the healthy brain assessed by magnetic resonance imaging. PLoS ONE 2013; 8 (4) e62588
• 19 Bailey DM, Jones DW, Sinnott A , et al. Impaired cerebral haemodynamic function associated with chronic traumatic brain injury in professional boxers. Clin Sci (Lond) 2013; 124 (3) 177-189
• 20 Hamner JW, Cohen MA, Mukai S, Lipsitz LA, Taylor JA. Spectral indices of human cerebral blood flow control: responses to augmented blood pressure oscillations. J Physiol 2004; 559 (Pt 3) 965-973
• 21 Low DA, Wingo JE, Keller DM , et al. Dynamic cerebral autoregulation during passive heat stress in humans. Am J Physiol Regul Integr Comp Physiol 2009; 296 (5) R1598-R1605