Extended neuromonitoring in aortic arch surgery

Abstract

Background Aortic arch repair for aortic dissection is still associated with a high mortality rate. Providing adequate means of neuromonitoring to guide cerebral hemodynamics is advantageous, especially during selective anterior cerebral perfusion (SACP). Objective We aimed to investigate an easy multimodal neuromonitoring set-up consisting of processed electroencephalography (EEG), near infrared spectroscopy (NIRS), and transcranial doppler sonography (TCD). Material and methods We collected intraoperative data from six patients undergoing surgery for aortic dissection. In addition to standard hemodynamic monitoring, patients underwent continuous bilateral NIRS, processed EEG with bispectral index (BIS), and intermittent transcranial doppler sonography of the medial cerebral artery (MCA) with a standard B‑mode ultrasound device. Doppler measurements were taken bilaterally before cardiopulmonary bypass (CPB), during CPB, and during SACP at regular intervals. Results Of the patients four survived without neurological deficits while two suffered fatal outcomes. Of the survivors two suffered from transient postoperative delirium. Multimodal monitoring led to a change in CPB flow or cannula repositioning in three patients. Left-sided mean flow velocities of the MCA decreased during SACP, as did BIS values. Conclusion Monitoring consisting of BIS, NIRS, and TCD may have an impact on hemodynamic management in aortic arch operations.

Perioperative cerebral perfusion in aortic arch surgery: a potential link with neurological outcome

“…Neuromonitoring studies suggest a safety threshold for intraoperative CBF of 50% from physiological baseline values, as values below this are indicative for cerebral ischaemia [ 19 , 20 ]. Indeed, our ROC analyses, although with rather poor discriminative value, confirm that MCAv decreases >50% during ASCP are associated with 48% increased risk of postoperative neurological deficits.…”

ASNM and ASN joint guidelines for transcranial Doppler ultrasonic monitoring: An update

“…Currently existing monitoring methods do have certain limitations if applied alone for detection of brain damage. However, a multimodal neuromonitoring will allow recognition of injury during surgery with interventions that will lead to possible reduction of subsequent neurological deficits 104–111 …”

“…A sudden increase in resistance may indicate compromised venous return, perhaps due to a malpositioned or partially occluded venous cannula. Post‐CPB persistence of the high‐resistance TCD waveform pattern may suggest developing cerebral edema and a need for ultrafiltration. TCDNM quantitative and qualitative identification of embolization may improve surgical and perfusion technique, 104,126,127 facilitate correction of technical problems such as an air leak, 128,129 and improve patients’ outcome 71,111,130,112 …”

“…However, a multimodal neuromonitoring will allow recognition of injury during surgery with interventions that will lead to possible reduction of subsequent neurological deficits. [104][105][106][107][108][109][110][111] At present, experience with neurophysiologic techniques includes measuring CBFV and emboli by TCDNM and regional cerebral venous…”

“…TCDNM quantitative and qualitative identification of embolization may improve surgical and perfusion technique, 104,126,127 facilitate correction of technical problems such as an air leak, 128,129 and improve patients' outcome. 71,111,130,112…”