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5 results

  • 5 - Cerebral Oximetry

  • from Section 1 - Hemodynamic Monitoring in the Perioperative Period
    • By
  • Edited by Alexandre Joosten, University of California, Los Angeles, Maxime Cannesson, University of California, Los Angeles, Robert G. Hahn, Karolinska Institutet, Stockholm
  • Book:
    Hemodynamic Monitoring and Fluid Therapy during Surgery
    Published online:
    11 April 2024
    Print publication:
    02 May 2024, pp 57-66

  • Summary

    Cerebral oxygen consumption accounts for around 20% of the whole-body oxygen consumption. In the perioperative period,monitoring the adequacy of cerebral perfusion and oxygen delivery is desirable, since they can be compromised by several factors related to surgery and anaesthesia Cerebral oximeters are monitoring devices based on near infrared spectroscopy (NIRS) providing a continuous and non-invasive assessment of cerebral oxygenation. Cerebral oximetry is commonly adopted in cardiac surgery, with the widest application in aortic arch procedures and pediatric congenital heart surgery.There is growing interest in its application in non-cardiac surgery settings. Whilst the evidence for a role in impacting patient outcomes is still not completely clear even in cardiac surgery, cerebral oximetry can be a useful adjunct in perioperative monitoring and in hemodynamic management, provided that it is interpreted in the context of other physiological variables.

  • Impact of the superior cavopulmonary anastomosis on cerebral oxygenation

  • Nikhil Thatte, Lingyu Zhou, John N. Kheir
  • Journal:
    Cardiology in the Young / Volume 30 / Issue 4 / April 2020
    Published online by Cambridge University Press:
    16 March 2020, pp. 585-587
  • Background:

    Patients with univentricular heart disease may undergo a superior cavopulmonary anastomosis, an operative intervention that raises cerebral venous pressure and impedance to cerebral venous return. The ability of infantile cerebral autoregulation to compensate for this is not well understood.

    Materials and methods:

    We identified all patients undergoing a superior cavopulmonary anastomosis (cases) and compared metrics of cerebral oxygenation upon admission to the ICU with patients following repair of tetralogy of Fallot or arterial switch operation (controls). The primary endpoint was cerebral venous oxyhaemoglobin saturation measured from an internal jugular venous catheter. Other predictor variables included case–control assignment, age, weight, sex, ischemic times, arterial oxyhaemoglobin saturation, mean arterial blood pressure, and superior caval pressure.

    Results:

    A total of 151 cases and 350 controls were identified. The first post-operative cerebral venous oxyhaemoglobin saturation was significantly lower following superior cavopulmonary anastomosis than in controls (44 ± 12 versus 59 ± 15%, p < 0.001), as was arterial oxyhaemoglobin saturation (81 ± 9 versus 98 ± 5%, p < 0.001). Cerebral venous oxyhaemoglobin saturation correlated poorly with superior caval pressure in both groups. When estimated by linear mixed effects model, arterial oxyhaemoglobin saturation was the primary determinant of central venous oxyhaemoglobin saturation in both groups (β = 0.79, p = 3 × 10−14); for every 1% point increase in arterial oxyhaemoglobin saturation, there was a 0.79% point increase in venous oxyhaemoglobin saturation. In this model, no other predictors were significant, including superior caval pressure and case–control assignment.

    Conclusion:

    Cerebral autoregulation appears to remain intact despite acute imposition of cerebral venous hypertension following superior cavopulmonary anastomosis. Following superior cavopulmonary anastomosis, cerebral venous oxyhaemoglobin saturation is primarily determined by arterial oxyhaemoglobin saturation.

  • MP32: Paramedics using near-infrared spectroscopy in out-of-hospital cardiac arrest: a feasibility study

  • I. Drennan, J. Gilgan, K. Goncharenko, S. Lin
  • Journal:
    Canadian Journal of Emergency Medicine / Volume 20 / Issue S1 / May 2018
    Published online by Cambridge University Press:
    11 May 2018, p. S52
    Print publication:
    May 2018
    • Article
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  • Introduction: Long-term outcomes following out-of-hospital cardiac arrest (OHCA) remain poor. Two-thirds of OHCA patients surviving to hospital admission die from neurological injuries, and of those discharged, one-third have irreversible cognitive disabilities due to cerebral ischemia. Near-infrared spectroscopy (NIRS) is a non-invasive imaging technique which is able to continuously detect regional cerebral oxygenation (rSO2). NIRS monitoring has been used to measure rSO2 during in-hospital cardiac arrest resuscitation. Our study is the first feasibility study of paramedics applying NIRS monitoring during OHCA resuscitation. Methods: One NIRS monitor (Equanox 7600; Nonin, Plymouth, MI, USA) was placed on an Emergency Response Unit (ERU) with York Region Paramedic Services. ERU paramedics were trained to apply the device to patients foreheads during OHCA resuscitation and record rSO2 until arrival at hospital or termination of resuscitation. Paramedics did not alter any aspect of patient care by using the NIRS monitor. They were instructed to press an action marker on the device during ACLS interventions (e.g. defibrillation, intubation, medications, etc). rSO2 data was later downloaded for analysis. Our feasibility criteria was to obtain >70% of data files with rSO2 data and >70% of data files with event markers. Results: Data was collected from 24 OHCA patients over a period of 10 months. 19 cases (79%) files contained rSO2 data and 17 cases (71%) had event markers. The rSO2 data present in each file varied widely from complete recording for the entire call duration to sporadic brief readings. Event markers varied from 1 to 10 markers spaced throughout the cases. Conclusion: This is the first study to demonstrate that the use of NIRS by paramedics as part of OHCA resuscitation is feasible. Future studies are required to determine how rSO2 monitoring can be used to guide OHCA resuscitation. The results of this study will help inform protocols for future studies evaluating the use of NIRS in the out-of-hospital setting.

  • 16 - Anaesthetic management of posterior fossa surgery

  • from Section 3 - Neuroanaesthesia
  • Edited by Basil F. Matta, David K. Menon, Martin Smith
  • Book:
    Core Topics in Neuroanaesthesia and Neurointensive Care
    Published online:
    05 December 2011
    Print publication:
    13 October 2011, pp 237-245

  • Summary

    A number of technologies aimed at detecting oxygen supply/demand imbalance have been developed of which jugular bulb oximetry is the most mature. More recently, near-infrared spectroscopy and direct brain tissue oxygen measurement have become clinically available. The brain extracts oxygen from arterial blood at a rate to supply its global metabolic requirements leaving an oxygen-poor venous effluent. Jugular venous oxygenation can be measured intermittently by serial blood sampling or continuously by fibre-optic oximetry. Jugular bulb oximetry can be used to detect disorders of both cerebral autoregulation and carbon dioxide reactivity. Cerebral oxygenation has been studied by jugular bulb cannulation during aneurysm clipping surgery. Jugular venous saturation has been studied as a potential prognostic marker in comatose patients in which spontaneous circulation has been restored after cardiac arrest. Experience with brain tissue oxygenation microsensors is increasing and clearly these provide a very direct measurement of tissue metabolism.

  • Case 36 - Awakecraniotomy and intraoperative neurologic decline

  • from Section I - Neuroanesthesia
  • Edited by George A. Mashour, Ehab Farag
  • Book:
    Case Studies in Neuroanesthesia and Neurocritical Care
    Published online:
    03 May 2011
    Print publication:
    03 February 2011, pp 113-116

  • Summary

    Intraoperative neurologic monitoring has been the subject of intense research for many years, the goal being to accurately identify intraoperative cerebral ischemia, and predict which patients may benefit from intraoperative shunting. This chapter presents a case study of a 73-year-old male scheduled for a right carotid endarterectomy (CEA) under general anesthesia. The patient experienced delayed emergence and displayed signs of a left hemiparesis. A diffusion-weighted magnetic resonance imaging confirmed the presence of a right-sided ischemic stroke in the middle cerebral artery (MCA) territory. For patients undergoing CEA under general anesthesia a number of monitoring modalities exist: monitors of cerebral hemodynamics, monitors of cerebral oxygenation and metabolism, and monitors of electrophysiologic parameters. None of the monitoring modalities commonly used for CEA under general anesthesia have been shown to either reliably identify or prevent cerebral ischemia or stroke, nor predict which patients may benefit from shunt placement.