Impact of temperature on the Narcotrend Index during hypothermic cardiopulmonary bypass in children with sevoflurane anesthesia

Abstract

Background:

During cardiopulmonary bypass (CPB) in children, anesthesia maintained by sevoflurane administered via the oxygenator is increasingly common. Anesthetic uptake and requirement may be influenced by the non-physiological conditions during hypothermic CPB. Narcotrend-processed EEG monitoring may, therefore, be useful to guide the administration of sevoflurane during this phase.

Objective:

The objective of this prospective, clinical, observational study was to assess the correlation between body temperature, Narcotrend Index (NI) and administered sevoflurane in children during CPB.

Methods:

Forty-four children aged 0 to 10 years undergoing hypothermic cardiac surgery were studied. On bypass, anesthesia was maintained with sevoflurane administered via the oxygenator of the heart-lung machine. Nasopharyngeal temperature, NI and minimum alveolar concentration (MAC) of sevoflurane were recorded in intervals of 10 minutes. Expiratory gas was sampled from the oxygenator’s sole expiratory port via a separate connecting line and the MAC was measured by the agent analyzer of the anesthesia machine.

Results:

Raw (r = 0.74) and corrected (r = 0.73) r-values show that narcosis depth (as indicated by NI) can primarily be explained by the interaction of MAC and temperature. The analysis of variance (without the interaction term) confirms the significant and independent association of both factors, MAC (p<0.004, 95%CI: 0.19 to 0.46) and temperature (p<0.0001, 95%CI: 0.68 to 0.78), with the NI. During hypothermia, sevoflurane had been reduced significantly (r = 0.41, p<0.0001, 95%CI: 0.33 to 0.48).

Conclusion:

Perfusionists and anesthetists should be aware of the results of processed electroencephalograph (EEG) monitoring during CPB. Sevoflurane requirements differ inter-individually; they may decrease during cooling and increase during rewarming. Therefore, it seems reasonable to include the results of processed EEG monitoring when administering sevoflurane during CPB in children, but further studies are necessary to confirm this thesis.

Keywords

EEG Narcotrend infants children sevoflurane hypothermia cardiopulmonary bypass cardiac surgery

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References

Tempe

Siddiquie

RA.

Awareness during cardiac surgery. J Cardiothorac Vasc Anesth 1999; 13: 214–219.

Nitzschke

Wilgusch

Kersten

et al . Bispectral index guided titration of sevoflurane in on-pump cardiac surgery reduces plasma sevoflurane concentration and vasopressor requirements: a prospective, controlled, sequential two-arm clinical study. Eur J Anaesthesiol 2014; 31: 482–490.

Leslie

Myles

Forbes

Chan

MT.

The effect of bispectral index monitoring on long-term survival in the B-aware trial. Anesth Analg 2010; 110: 816–822.

Monk

Weldon

BC.

Anesthetic depth is a predictor of mortality: it’s time to take the next step. Anesthesiology 2010; 112: 1070–1072.

Hall

RI.

Cardiopulmonary bypass and the systemic inflammatory response: effects on drug action. J Cardiothorac Vasc Anesth 2002; 16: 83–98.

Tobias

Russo

Changes in near infrared spectroscopy during deep hypothermic circulatory arrest. Ann Card Anaesth 2009; 12: 17–21.

Stecker

Cheung

Pochettino

et al . Deep hypothermic circulatory arrest: I. Effects of cooling on electroencephalogram and evoked potentials. Ann Thorac Surg 2001; 71: 14–21.

Antognini

JF.

Hypothermia eliminates isoflurane requirements at 20 degrees C. Anesthesiology 1993; 78: 1152–1156.

Kreuer

Wilhelm

The Narcotrend monitor. Best Pract Res Clin Anaesthesiol 2006; 20: 111–9.

10.

Weber

Hollnberger

Gruber

Frank

Taeger

. The correlation of the Narcotrend Index with endtidal sevoflurane concentrations and hemodynamic parameters in children. Paediatr Anaesth 2005; 15: 727–732.

11.

Abbott Australasia PTY LTD. Sevorane product information version 10. Dec 2014.

12.

McMullan

Alston

Tyrrell

Volatile anaesthesia during cardiopulmonary bypass. Perfusion 2015; 30: 6–16.

13.

Wiesenack

Wiesner

Keyl

et al . In vivo uptake and elimination of isoflurane by different membrane oxygenators during cardiopulmonary bypass. Anes-thesiology 2002; 97: 133–138.

14.

Nitzschke

Wilgusch

Kersten

et al . Changes in sevoflurane plasma concentration with delivery through the oxygenator during on-pump cardiac surgery. Br J Anaesth 2013; 110: 957–965.

15.

Short

Leslie

Campbell

et al . A pilot study for a prospective, randomized, double-blind trial of the influence of anesthetic depth on long-term outcome. Anesth Analg 2014; 118: 981–986.

16.

Jiang

Qiao

Lin

Application of Narcotrend monitor for evaluation of depth of anesthesia in infants undergoing cardiac surgery: a prospective control study. Braz J Anesthesiol 2013; 63: 273–278.

17.

Mathew

Weatherwax

East

White

Reves

JG.

Bispectral analysis during cardiopulmonary bypass: the effect of hypothermia on the hypnotic state. J Clin Anesth 2001; 13: 301–305.

18.

Stein

Glick

Minhaj

Drum

Tung

Relationship between anesthetic depth and venous oxygen saturation during cardiopulmonary bypass. Anesthesiology 2010; 113: 35–40.

19.

Chandran Mahaldar

Gadhinglajkar

Sreedhar

Sevoflurane requirement to maintain bispectral index-guided steady-state level of anesthesia during the rewarming phase of cardiopulmonary bypass with moderate hypothermia. J Cardiothorac Vasc Anesth 2013; 27: 59–62.

20.

Liu

Dhara

SS.

Monitoring oxygenator expiratory isoflurane concentrations and the bispectral index to guide isoflurane requirements during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2005; 19: 485–487.

21.

Laussen

Murphy

Zurakowski

Sullivan

McGowan

Jr. Demaso

DR.

Bispectral index monitoring in children undergoing mild hypothermic cardiopulmonary bypass. Paediatr Anaesth 2001; 11: 567–573.

22.

Dewandre

Hans

Bonhomme

Brichant

Lamy

Effects of mild hypothermic cardiopulmonary bypass on EEG bispectral index. Acta Anaesthesiol Belg 2000; 51: 187–190.