Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Feb;64(2):131-137.
doi: 10.4103/ija.IJA_697_19. Epub 2020 Feb 4.

Quantifying influence of epidural analgesia on entropy guided general anaesthesia using sevoflurane - A randomised controlled trial

Murugesan Ravishankar  1 , Dalena Merin Mathew  2 , V R Hemanthkumar  1 , Parthasarathy Srinivasan  1
Affiliations

Quantifying influence of epidural analgesia on entropy guided general anaesthesia using sevoflurane - A randomised controlled trial

Murugesan Ravishankar et al. Indian J Anaesth. 2020 Feb.

Abstract

Background and aims: Minimum alveolar concentration (MAC) of inhalational agent denotes the requirement of it to maintain adequate plane of general anaesthesia. The precision to the maintenance of anaesthesia can be further guided by use of entropy to titrate the depth of anaesthesia. Regional anaesthesia and the concomitant deafferentation will decrease the need of general anaesthetics. We conducted a randomised double-blind trial to quantify the effect of addition of regional anaesthesia to sevoflurane based general anaesthesia technique guided by entropy to achieve satisfactory depth of anaesthesia.

Methods: Forty patients posted for elective laparotomies were randomised to two groups. All patients received a bolus followed by an epidural infusion. Group GE (general anaesthesia + epidural bupivacaine) received 0.25% epidural bupivacaine and Group GS received epidural saline. Both groups received narcotic, relaxant and sevoflurane anaesthesia guided by entropy monitoring. The state entropy (SE) was maintained at 40-60 by titrating end tidal sevoflurane concentration (ETsevo). Heart rate, blood pressure, SpO2, end tidal carbon dioxide (ETCO2) and sevoflurane were recorded.

Results: Both groups were similar in heart rate and mean blood pressure during anaesthesia maintenance. The minimum ETSevo required to maintain entropy between 40 and 60 in group GE was 0.53% compared to 0.95% in group GS the epidural saline group (P < 0.001). The end-tidal sevoflurane requirement to maintain adequate depth of anaesthesia dropped by 44.2% in group GE.

Conclusion: Lower concentrations of volatile anaesthetic are required when entropy-guided general anaesthesia is combined with regional blockade.

Keywords: End tidal; entropy; epidural; sevoflurane.

PubMed Disclaimer

Conflict of interest statement

There are no conflicts of interest.

Figures

Figure 1
Figure 1
Changes in Mean Arterial Pressure and Heart rate in the two groups (The dots represent mean values and error bars represent SD which have been indicated on one side for clarity)
Figure 2
Figure 2
Changes in State and Response Entropy over time in both groups
Figure 3
Figure 3
Changes in End Tidal Sevoflurane Concentration compared with State Entropy over time in a single case
Figure 4
Figure 4
Step-wise titration of end tidal sevoflurane during maintenance
Figure 5
Figure 5
Lowest end tidal Sevoflurane and Lowest MAC in both groups (Each point represents one patient. MAC is plotted from lowest to highest value for clarity)
See this image and copyright information in PMC

References

    1. Takamatsu I, Ozaki M, Kazama T. Entropy indices vs the bispectralindex™ for estimating nociception during sevoflurane anaesthesia. Br J Anaesth. 2006;96:620–6. - PubMed
    1. Casati L, Fernández-Galinski S, Barrera E, Pol O, Puig MM. Isoflurane requirements during combined general/epidural anesthesia for major abdominal surgery. Anesth Analg. 2002;94:1331–7. - PubMed
    1. Hodgson PS, Liu SS. Epidural lidocaine decreases sevoflurane requirement for adequate depth of anesthesia as measured by the Bispectral Index monitor. Anesthesiology. 2001;94:799–803. - PubMed
    1. Zhang J, Zhang W, Li B. The effect of epidural anesthesia with different concentrations of ropivacaine on sevoflurane requirements. Anesth Analg. 2007;104:984–6. - PubMed
    1. Choi SR, Lim YH, Lee SC, Lee JH, Chung CJ. Spectral entropy monitoring allowed lower sevoflurane concentration and faster recovery in children. Acta Anaesthesiol Scand. 2010;54:859–62. - PubMed