Lactate flux during carotid endarterectomy under general anesthesia: correlation with various point-of-care monitors

Abstract

Purpose The ability to assess the brain-at-risk during carotid endarterectomy (CEA) under general anesthesia remains a major clinical problem. Point-of-care monitoring can potentially dictate changes to management intraoperatively. In this observational study, we examined the correlation between a series of point-of-care monitors and lactate flux during CEA. Methods Both neurosurgeons and vascular surgeons participated in the study. The patients underwent arterialjugular venous blood sampling for oxygen, carbon dioxide, glucose, and lactate, n = 26; bispectral index (BIS) monitoring ipsilateral to side of surgery, n = 26; raw and processed electroencephalogram (EEG), n = 22; and bi-frontal cerebral oximetry using the Fore-Sight monitor, n = 20. Results One patient experienced a new neurological deficit when assessed at 24 hr following surgery. Lactate flux into the brain was correlated with the greatest decrease in cerebral oximetry with carotid cross-clamping; lactate efflux was correlated with the least. The most noticeable changes in processed EEG (density spectral analysis) were also seen with lactate influx, but at a slower time resolution than cerebral oximetry. Loss of autoregulatory behaviour was demonstrated with lactate influx; however, no correlation was seen between lactate flux and BIS monitoring. Conclusion There was a correlation between cerebral oximetry and lactate flux during carotid cross-clamping. The Fore-Sight monitor may be of value as a point-of-care monitor during CEA under general anesthesia. A novel finding of this study is lactate flux into the brain in the presence of a large difference in cerebral oxygenation during cross-clamping of the carotid artery. Registered at clinicaltrials.gov: NCT000737334. RésuméObjectif La capacite´d'e´valuer le cerveau a`risque pendant une endarte´riectomie carotidienne (EC) sous anesthe´sie ge´ne´rale demeure un proble`me clinique important. Le monitorage au chevet pourrait potentiellement conduire ad es modifications de la prise en charge perope´ratoire. Dans cette e´tude observationnelle, nous avons explore´la corre´lation entre une se´rie de moniteurs au chevet et le flux de lactate pendant une EC. Méthode Des neurochirurgiens et des chirurgiens vasculaires ont pris part a`cette e´tude. Les patients ont subi un e´chantillonnage du sang veineux arte´riel jugulaire pour de´tecter les concentrations d'oxyge`ne, de dioxyde de carbone, de glucose et de lactate, n = 26; monitorage par index bispectral (BIS) ipsilate´ral au côte´de la chirurgie, n = 26; e´lectroence´phalogramme (EEG) brut et apre`s

Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery

“…Similarly, rScO 2 correlates to SjvO 2 (Williams et al, 1994b; Grubhofer et al, 1997; Espenell et al, 2010) and a correlation to stump pressure is also reported (Kragsterman et al, 2004; Yamamoto et al, 2007; Lee et al, 2008; Manwaring et al, 2010; Tambakis et al, 2011) so that a low stump (<40 mmHg) results in a large change in rScO 2 (Tambakis et al, 2011) but the relationship might be absent in a large series of patients (Pedrini et al, 2012). rScO 2 and systemic blood pressure correlate, with higher pressures leading to better oxygenation values (Williams et al, 1994c; Ritter et al, 2011).…”

Cerebral oxygen desaturation during one-lung ventilation: correlation with hemodynamic variables

“…In addition, prior work has indicated that meaningful alterations in cerebral saturation can be determined in this manner, for example, pre-and post-carotid cross-clamping with carotid endarterectomy. 10,11 Lastly, establishing an a priori agreed upon baseline permits true comparisons across the maximal number of studies. 7 In these experiments, we show desaturations using the same type of cerebral oximeter (i.e., CasMed FORE-SIGHT) used by Hemmerling et al 7 This oximeter claims absolute cerebral oximetry, not just documentation of trends.…”

“…7 We have also used this monitor to document changes in cerebral saturation with cross-clamping during carotid endarterectomy under general anesthesia. 11 Cardiac output measurement utilizing the FloTrac system has been recently reviewed. 14 This device has been found to provide a good estimate of cardiac output compared with pulmonary artery thermodilution, which is considered the gold standard; however, other work highlights the potential limitation of the currently available minimally invasive cardiac output devices when compared with thermodilution.…”

Monitoring for Carotid Endarterectomy

“…Cerebral oximetry 16,17 16-Channel EEG 18 Stump pressure 6 Jugular bulb venous oximetry 19,20 Processed EEG 21 Xenon 133 CBF 22 Conjunctival oxygen tension 23 SSEP 9,10 MEP 8 EEG = electroencephalography; SSEP = somatosensory-evoked potentials; MEP = motor-evoked potential; CBF = cerebral blood flow.…”