Combined thoracic paravertebral and pectoral nerve blocks for breast surgery under sedation: a prospective observational case series.

Avoidance of general anaesthesia for breast surgery may be because of clinical reasons or patient choice. There is emerging evidence that the use of regional anaesthesia and the avoidance of volatile anaesthetics and opioid analgesia may have beneficial effects on oncological outcomes. We conducted a prospective observational case series of 16 breast cancer surgeries performed under thoracic paravertebral plus pectoral nerve block with propofol sedation to demonstrate feasibility of technique, patient acceptability and surgeon satisfaction. Fifteen out of 16 cases were successfully completed under sedation and regional anaesthesia, with one conversion to general anaesthesia. Eleven out of 16 cases required low-dose intra-operative opioid analgesia. Out of the 15 surgical procedures completed under regional anaesthesia with sedation, all patients experienced either no or minimal intra-operative pain, and all would choose this anaesthetic technique again. Surgeon-reported operating conditions were 'indistinguishable from general anaesthesia' in most cases, and surgeons were 'extremely satisfied' or 'satisfied' with the technique after every procedure. Combined thoracic paravertebral plus pectoral nerve block with intra-operative sedation is a feasible technique for breast surgery.

Surgicric 2: A comparative bench study with two established emergency cricothyroidotomy techniques in a porcine model.

BACKGROUND: 'Can't Intubate, Can't Oxygenate' is a rare but life threatening event. Anaesthetists must be trained and have appropriate equipment available for this. The ideal equipment is a topic of ongoing debate. To date cricothyroidotomy training for anaesthetists has concentrated on cannula techniques. However cases reported to the NAP4 audit illustrated that they were associated with a high failure rate. A recent editorial by Kristensen and colleagues suggested all anaesthetists must master a surgical technique. The surgical technique for cricothyroidotomy has been endorsed as the primary technique by the recent Difficult Airway Society 2015 guidelines. METHODS: We conducted a bench study comparing the updated Surgicric 2 device with a scalpel-bougie-tube surgical technique, and the Melker seldinger technique, using a porcine model. Twenty six senior anaesthetists (ST5+) participated. The primary outcome was insertion time. Secondary outcomes included success rate, ease of use, device preference and tracheal trauma. RESULTS: There was a significant difference (P<0.001) in the overall comparisons of the insertion times. The surgical technique had the fastest median time of 62 s. The surgical and Surgicric techniques were significantly faster to perform than the Melker (both P<0.001). The surgical technique had a success rate of 85% at first attempt, and 100% within two attempts, whereas the others had failed attempts. The surgical technique was ranked first by 50% participants and had the lowest grade of posterior tracheal wall trauma, significantly less than the Surgicric 2 (P=0.002). CONCLUSIONS: This study supports training in and the use of surgical cricothyroidotomy by anaesthetists.

Temporal aggregation bias and inference of causal regulatory networks.

Time course experiments with microarrays have begun to provide a glimpse into the dynamic behavior of gene expression. In a typical experiment, scientists use microarrays to measure the abundance of mRNA at discrete time points after the onset of a stimulus. Recently, there has been much work on using these data to infer causal regulatory networks that model how genes influence each other. However, microarray studies typically have slow sampling rates that can lead to temporal aggregation of the signal. That is, each successive sampling point represents the sum of all signal changes since the previous sample. In this paper, we show that temporal aggregation can bias algorithms for causal inference and lead them to discover spurious relations that would not be found if the signal were sampled at a much faster rate. We discuss the implications of temporal aggregation on inference, the problems it creates, and potential directions for solutions.