[Hyperthermia after obstetrical epidural anesthesia]

Unlike epidural anaesthesia for general surgery or caesarean section, épidural analgesia for labour leads to maternal hyperthermia. Its recent demonstration is probably related to the multiple influencing factors: site of measurement, ambient temperature, previous labour duration and dilatation at the time of epidural puncture, and occurrence of shivering. During the first 2 to 5 hours of epidural analgesia, there is a weak--if any--thermic increase. Then, when labour is prolonged (mostly primiparae) a linear increase occurs with time, at a mean rate of 1 degree C per 7 hours. The pathophysiology remains hypothetical: heat loss (sweating and hyperventilation) would be reduced during epidural analgesia and therefore surpassed by the important labour-induced heat production. This hyperthermia has been correlated with foetal tachycardia but never with any infectious process. A potential deleterious effect is still debated and may lead to propose an active cooling for the mother. This hyperthermia must also be recognized to avoid an inadequate obstetrical attitude (antibiotics, extractions).