Background Hypotension following spinal anesthesia for Cesarean delivery is common. Fluid loading is recommended to prevent hypotension, but preload is often ineffective. In non-pregnant patients, coloading has been shown to better maintain cardiac output after spinal anesthesia. The purpose of this meta-analysis was to determine whether the timing of the fluid infusion, before (preload) or during (coload) induction of spinal anesthesia for Cesarean delivery, influences the incidence of maternal hypotension or neonatal outcome. Methods We retrieved randomized controlled trials that compared a fluid preload with coload in patients undergoing spinal anesthesia for elective Cesarean delivery. We graded the articles for quality of reporting (maximum score = 5) and recorded the incidence of hypotension, lowest blood pressure, the incidence of maternal nausea and vomiting, umbilical cord pH, and Apgar scores. We combined the results using random effects modelling. Results We retrieved eight studies comprised of 518 patients. The median quality score for the published studies was three. The incidence of hypotension in the coload group was 159/268 (59.3%) compared with 156/250 (62.4%) in the preload group (odds ratio [OR] = 0.93; 95% confidence interval [CI] 0.54-1.6). There were no significant differences between groups in any of the other outcomes. Conclusions It is unnecessary to delay surgery in order to deliver a preload of fluid. Regardless of the fluid loading strategy, the incidence of maternal hypotension is high. Prophylactic or therapeutic vasopressors may be required in a significant proportion of patients. RésuméContexte L'hypotension est un phe´nome`ne courant a`la suite d'une rachianesthe´sie pour un accouchement par ce´sarienne. Il est recommande´d'administrer une charge liquidienne pour pre´venir l'hypotension, mais la pre´-charge est souvent peu efficace. Chez les patients et patientes non enceintes, il a e´te´de´montre´que la co-charge maintenait mieux le de´bit cardiaque apre`s une rachianesthe´sie. L'objectif de cette me´ta-analyse e´tait de de´terminer si le moment de perfusion liquidienne, soit avant (pre´-charge) ou pendant (co-charge) l'induction de la rachianesthe´sie pour un accouchement par ce´sarienne, influençait l'incidence d'hypotension chez la me`re ou le devenir du nouveau-ne´. Méthode Nous avons extrait des e´tudes randomise´es contrôle´es comparant une pre´-charge a`une co-charge liquidienne chez des patientes subissant une rachianesthe´sie pour un accouchement par ce´sarienne non urgent. Nous avons attribue´une note aux articles selon la qualite´de la pre´sentation (score maximal = 5) et note´l'incidence d'hypotension, la tension arte´rielle la plus basse, l'incidence de nause´es et vomissements chez la me`re, le pH du sang du cordon ombilical et les scores d'Apgar. Nous avons combine´les re´sultats a`l'aide d'un mode`le a`effets ale´atoires. 123Can J Anesth/J Can Anesth (2010) 57:24-31 DOI 10.1007 Résultats Nous avons retenu huit e´tudes comprenant 518 patientes. Le score ...

Background Clinical identification of lumbar spinous processes is inaccurate in most patients. The purpose of this study was to determine the number of patients required to train anesthesiologists in the use of ultrasound imaging to accurately identify the lumbar spinous processes. Methods In this pilot study, two anesthesiologists studied patients scheduled for a diagnostic computed tomography (CT) scan, including the lumbar spine. Before the CT scan, the anesthesiologist completed a systematic ultrasound scan of the lumbar spine and placed a radio-opaque marker at a designated level. The actual level was determined by a radiologist after reviewing the CT scans. The primary outcome was the number of procedures each anesthesiologist needed (by cumulative sum analysis) to be able to identify the designated spinous process 90% of the time. Secondary outcomes included the overall success rate, the magnitude of the failures (number of segments from the designated spinous process), and the incidence of spinal anomalies and their effect on reliability.Results We studied 74 patients. One anesthesiologist required 36 patients to meet reliability criteria, whereas the other required 22 patients. The overall accuracy rate was 68%. There were only two patients where the marker was placed more than one segment from the designated spinous process. The incidence of lumbar spine anomalies was 6.8% (n = 5), and 80% (n = 4) of these were associated with inaccurate marker placement. Conclusions It is possible to use ultrasound scanning to accurately identify the lumbar spinous processes in unselected patients. This result suggests that, with appropriate training, this tool can be used to enhance the accuracy of needle placement during neuraxial techniques.