Warming IV Fluids and Incidence of Hypotension

Inadvertent perioperative hypothermia during cesarean delivery is not rare and frequently neglected, despite the recommendations by clinical guidelines. Exposure to cold air and infusing non-warmed intravenous (iv) fluids are the other main sources of inadvertent hypothermia. Spinal anesthesia used during the cesarean delivery has also been demonstrated to impair normal autonomic thermoregulatory control and extend inadvertent perioperative hypothermia. Various measures such as pre-warming of patients or fluids before anesthesia, peroperative warming of iv fluids and active/passive cutaneous warming techniques have all been used to prevent or to reduce inadvertent perioperative hypothermia. This prospective, double-blinded, randomized, controlled study was undertaken to evaluate whether warming IV fluids (37 oC) resulted in lower incidence of hypotension, less ephedrine and transfusion requirement and lower fluid consumption than use of room-temperature fluids (22 oC) in cesarean delivery patients undergoing spinal anesthesia.

The hypothesis was that in elective caesarean delivery patients undergoing spinal anesthesia, warming intravenous fluids, would reduce the incidence of hypotension, ephedrine and transfusion requirement and volume consumption. Thus, the primary outcome measure of the present study was the incidence of intraoperative maternal hypotension and ephedrine requirement during spinal anaesthesia for caesarean section. Secondary outcome measures were total volume consumption, blood loss, pain scores, shivering and maternal and foetal side effects.