Epidural analgesia, intrapartum hyperthermia, and neonatal brain injury: a systematic review and meta-analysis.

BACKGROUND: Epidural analgesia is associated with intrapartum hyperthermia, and chorioamnionitis is associated with neonatal brain injury. However, it is not known if epidural hyperthermia is associated with neonatal brain injury. This systematic review and meta-analysis investigated three questions: (1) does epidural analgesia cause intrapartum hyperthermia, (2) is intrapartum hyperthermia associated with neonatal brain injury, and (3) is epidural-induced hyperthermia associated with neonatal brain injury? METHODS: PubMed, ISI Web of Knowledge, The Cochrane Library, and Embase were searched from inception to January 2020 using Medical Subject Headings (MeSH) terms relating to epidural analgesia, hyperthermia, labour, and neonatal brain injury. Studies were reviewed independently for inclusion and quality by two authors (Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach). Two meta-analyses were performed using the Mantel-Haenszel fixed effect method to generate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Forty-one studies were included for Question 1 (646 296 participants), 36 for Question 2 (11 866 021 participants), and two studies for Question 3 (297 113 participants). When the mode of analgesia was randomised, epidural analgesia was associated with intrapartum hyperthermia (OR: 4.21; 95% CI: 3.48-5.09). There was an association between intrapartum hyperthermia and neonatal brain injury (OR: 2.79; 95% CI: 2.54-2.3.06). It was not possible to quantify the association between epidural-induced hyperthermia and neonatal brain injury. CONCLUSIONS: Epidural analgesia is a cause of intrapartum hyperthermia, and intrapartum hyperthermia of any cause is associated with neonatal brain injury. Further work is required to establish if epidural-induced hyperthermia is a cause of neonatal brain injury.

Trunk muscle responses following unpredictable loading of an abducted arm.

This study investigated if asymmetry exists in the responses of trunk muscles to a perturbation of the trunk induced by loading of an outstretched arm. Nineteen healthy right-handed subjects were recruited into the study. Electromyographic recordings were made from trunk muscles (erector spinae and rectus abdominus) and upper limb muscles (deltoid). A weight was dropped into a receptacle held out laterally by the subjects. The perturbation induced a rise in EMG activity in the deltoid at a latency which was not different between the dominant and non-dominant arms. It also induced a rise in EMG activity in the contralateral trunk muscles. Although not significantly different, there was a trend for the responses from the right trunk to be longer than those from the left trunk. Furthermore, there were higher levels of EMG activity in the trunk muscles opposite the dominant arm than those in the trunk muscles opposite the non-dominant arm. This study reveals a pattern of trunk muscle activation following movement in the arm induced by loading of an outstretched hand that is different on the side of the back opposite the dominant arm than on the side of the back opposite the non-dominant arm. These results may have implications in terms of mechanisms contributing to low back pain and further work is warranted to examine these responses in left-handed individuals.