Predictive factors of maternal hypothermia during Cesarean delivery: a prospective cohort study.

PURPOSE: Although perioperative hypothermia may increase maternal morbidity, active warming is infrequently performed to maintain normothermia during Cesarean delivery (CD). The aim of this prospective observational study was to determine the factors associated with maternal hypothermia in this setting. METHODS: Women scheduled for elective or emergency CD were consecutively included in this study from November 2014 to October 2015. Maternal temperature was measured using an infrared tympanic thermometer on the patient's arrival in the operating room, at skin incision, and at the end of skin suture. Maternal hypothermia was defined by tympanic temperature < 36°C at the end of skin suture. Univariate analysis was performed, followed by multivariate logistic regression analysis, in order to determine the factors associated with maternal hypothermia at the end of the surgery. RESULTS: Three hundred fifty-nine women were included and analyzed during this study. The incidence of hypothermia was 23% (95% confidence interval, 18 to 27) among the total population included. According to multivariate analysis, obesity, oxytocin augmentation of labour, and use of active forced-air warming were associated with a decreased risk of maternal hypothermia, while maternal temperature < 37.1°C on arrival in the operating room, maternal temperature < 36.6°C at skin incision, and an infused volume of fluids > 650 mL were significantly associated with maternal hypothermia. Both goodness of fit and predictive value of multivariate analysis were high. CONCLUSION: Several predictive factors for maternal hypothermia during CD were identified. These factors should be taken into account to help prevent maternal hypothermia during CD.

The pupillary light reflex for predicting the risk of hypotension after spinal anaesthesia for elective caesarean section.

INTRODUCTION: The balance between the sympathetic and parasympathetic systems could be used to predict the onset of hypotension following spinal anaesthesia. The autonomic innervation of the pupil may reflect this balance. The aim of this study was to evaluate the ability of pupillometry to predict the risk of hypotension after spinal anaesthesia for caesarean section. METHODS: Two hundred patients receiving spinal anaesthesia for caesarean section were recruited. Changes in pupillary diameter, pupillary reaction latency, pupil constriction velocity and maximum and minimum pupillary diameters were measured with a pupillometer (Neurolight®, IDMed) prior to induction of spinal anaesthesia with 10mg bupivacaine and fentanyl 30µg. Hypotension was defined as a systolic blood pressure drop of > 20% compared with the baseline value. RESULTS: A total of 141 patients (70%) presented at least one episode of hypotension. Pupillary reaction latency can poorly predict hypotension and severe hypotension after spinal anaesthesia. The areas under the receiver-operating characteristic curves were 0.654 (95% confidence interval: 0.584-0.720, P=0.0001) and 0.633 (95% confidence interval: 0.562-0.700, P=0.004) for optimal threshold values of 223 and 231ms, respectively. In multivariate analysis, a baseline systolic blood pressure > 130mmHg (odds ratio: 1.98, P=0.04) and a PRL > 223ms (odds ratio: 3.42, P=0.0002) were independently associated with the risk of spinal anaesthesia-related hypotension. CONCLUSION: Following spinal anaesthesia in patients undergoing caesarean section, though the predictive capacity pupillary reaction latency for the onset of hypotension and severe hypotension is poor, it is nevertheless the strongest predictor of hypotension identified in our study.