5 results found
Morton S, Kua J, Mullington CJ, 2021, Epidural analgesia, intrapartum hyperthermia, and neonatal brain injury: a systematic review and meta-analysis, BRITISH JOURNAL OF ANAESTHESIA, Vol: 126, Pages: 500-515, ISSN: 0007-0912
Mullington CJ, Low DA, Strutton PH, et al., 2020, A mechanistic study of the tremor associated with epidural anaesthesia for intrapartum caesarean delivery, International Journal of Obstetric Anesthesia, Vol: 43, Pages: 56-64, ISSN: 0959-289X
BackgroundIt 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.MethodsTwenty 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.ResultsThe 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).ConclusionThese results suggest that epidural top-up tremor is a form of non-thermoregulatory shivering triggered by a reduction in sensed body temperature.
Mullington CJ, Kua J, Malhotra S, 2020, The Timing of Labor Epidurals in COVID-19 Parturients: A Balance of Risk and Benefit, ANESTHESIA AND ANALGESIA, Vol: 131, Pages: E131-E132, ISSN: 0003-2999
Mullington CJ, Low DA, Strutton PH, et al., 2018, Body temperature, cutaneous heat loss and skin blood flow during epidural anaesthesia for emergency caesarean section, Anaesthesia, Vol: 73, Pages: 1500-1506, ISSN: 0003-2409
It is not clear how converting epidural analgesia for labour to epidural anaesthesia for emergency caesarean section affects either cutaneous vasomotor tone or mean body temperature. We hypothesised that topping up a labour epidural blocks active cutaneous vasodilation (cutaneous heat loss and skin blood flow decrease), and that as a result mean body temperature increases. Twenty women in established labour had body temperature, cutaneous heat loss and skin blood flow recorded before and after epidural top‐up for emergency caesarean section. Changes over time were analysed with repeated measures ANOVA. Mean (SD) mean body temperature was 36.8 (0.5)°C at epidural top‐up and 36.9 (0.6)°C at delivery. Between epidural top‐up and delivery, the mean (SD) rate of increase in mean body temperature was 0.5 (0.5) °C.h−1. Following epidural top‐up, chest (p < 0.001) and forearm (p = 0.004) heat loss decreased, but head (p = 0.05), thigh (p = 0.79) and calf (p = 1.00) heat loss did not change. The mean (SD) decrease in heat loss was 15 (19) % (p < 0.001). Neither arm (p = 0.06) nor thigh (p = 0.10) skin blood flow changed following epidural top‐up. Despite the lack of change in skin blood flow, the most plausible explanation for the reduction in heat loss and the increase in mean body temperature is blockade of active cutaneous vasodilation. It is possible that a similar mechanism is responsible for the hyperthermia associated with labour epidural analgesia.
Mullington CJ, Klungarvuth L, Catley M, et al., 2009, Trunk muscle responses following unpredictable loading of an abducted arm, GAIT & POSTURE, Vol: 30, Pages: 181-186, ISSN: 0966-6362
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