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A mechanistic study of the tremor associated with epidural anaesthesia for intrapartum caesarean delivery

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Mullington, IJOA, 2020, Word copy of manuscript.docxAccepted version526.49 kBMicrosoft WordView/Open
Title: A mechanistic study of the tremor associated with epidural anaesthesia for intrapartum caesarean delivery
Authors: Mullington, CJ
Low, DA
Strutton, PH
Malhotra, S
Item Type: Journal Article
Abstract: Background It is not known if the tremor associated with an epidural top-up dose for intrapartum caesarean delivery is thermoregulatory shivering. A tremor is only shivering if it has the same frequency profile as cold stress-induced shivering. Thermoregulatory shivering is a response to a reduction in actual body temperature, whereas non-thermoregulatory shivering may be triggered by a reduction in sensed body temperature. This mechanistic study aimed to compare: 1. the frequency profiles of epidural top-up tremor and cold stress-induced shivering; and 2. body temperature (actual and sensed) before epidural top-up and at the onset of tremor. Methods Twenty obstetric patients received an epidural top-up for intrapartum caesarean delivery and 20 non-pregnant female volunteers underwent a cold stress. Tremor, surface electromyography, core temperature, skin temperature (seven sites) and temperature sensation votes (a bipolar visual analog score ranging from −50 to +50 mm) were recorded. Results The mean (SD) primary oscillation (9.9 (1.9) Hz) frequency of epidural top-up tremor did not differ from that of cold stress-induced shivering (9.0 (1.6) Hz; P=0.194), but the mean (SD) burst frequency was slower (6.1 (1.2) × 10−2 Hz vs 6.9 (0.7) × 10−2 Hz, respectively; P=0.046). Before the epidural top-up dose, the mean (SD) core temperature was 37.6 (0.6) °C. Between the epidural top-up dose and the onset of tremor the mean (SD) core temperature did not change (–0.1 (0.1) °C; P=0.126), the mean (SD) skin temperature increased (+0.4 (0.4) °C; P=0.002) and the mean (SD) temperature sensation votes decreased (−12 (16) mm; P=0.012). Conclusion These results suggest that epidural top-up tremor is a form of non-thermoregulatory shivering triggered by a reduction in sensed body temperature.
Issue Date: 1-Aug-2020
Date of Acceptance: 17-Feb-2020
URI: http://hdl.handle.net/10044/1/79793
DOI: 10.1016/j.ijoa.2020.02.007
ISSN: 0959-289X
Publisher: Elsevier BV
Start Page: 56
End Page: 64
Journal / Book Title: International Journal of Obstetric Anesthesia
Volume: 43
Copyright Statement: © 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor/Funder: Obstetric Anaesthetists Association
Funder's Grant Number: N/A
Keywords: Body temperature
Caesarean delivery
Epidural anaesthesia
Temperature sensation
1114 Paediatrics and Reproductive Medicine
Publication Status: Published
Open Access location: https://doi.org/10.1111/anae.14454
Online Publication Date: 2020-02-21
Appears in Collections:Department of Surgery and Cancer
Faculty of Medicine