Intraoperative pain during caesarean delivery: Incidence, risk factors and physician perception

Background: Intraoperative pain is a possible complication of neuraxial anaesthesia for caesarean delivery. There is little information available about its incidence, risk factors and physician perception. Methods: Parturients undergoing spinal anaesthesia for elective caesarean delivery were enrolled. Before surgery, parturients were asked about preoperative anxiety on a verbal numerical scale (VNS), anticipated analgesic requirement, postoperative pain levels, Spielberger STATE-TRAIT inventory index, Pain Catastrophizing Scale. After surgery, parturients were asked to answer questions (intraoperative VNS pain). The anaesthesiologist and obstetrician were asked to fill out a questionnaire asking about perceived intraoperative pain. Influence of preoperative anxiety on intraoperative pain (yes/no) was assessed using logistic regression. Mc Fadden's R2 was calculated. The agreement in physician perception of intraoperative pain with reported pain by the parturient was examined by calculating Cohen's kappa and 95% Confidence Intervals (CI). Results: We included 193 parturients in our analysis. Incidence of intraoperative pain was 11.9%. Median intraoperative VNS pain of parturients with pain was 4.0 (1st quartile 4.0; 3rd quartile 9.0). Preoperative anxiety was not a good predictor of intraoperative pain (p-value of β-coefficient = 0.43, Mc Fadden's R2 = 0.01). Including further preoperative variables did not result in a good prediction model. Cohen's kappa between reported pain by parturient and by the obstetrician was 0.21 (95% CI: 0.01, 0.41) and by the anaesthesiologist was 0.3 (95% CI: 0.12, 0.48). Conclusions: We found a substantial incidence (11.9%) of intraoperative pain during caesarean delivery. Preoperative anxiety did not predict intraoperative pain. Physicians did not accurately identify parturients' intraoperative pain. Significance: Intraoperative pain occurred in 11.9% and severe intraoperative pain occurred in 1.11% of parturients undergoing elective caesarean delivery under spinal anaesthesia. We did not find any preoperative variables that could reliably predict intraoperative pain. Obstetricians and anaesthesiologists underestimated the incidence of intraoperative pain in our cohort and thus, more attention must be put to parturients' pain

High-resolution, long-term characterization of bacterial motility using optical tweezers

We present a single-cell motility assay, which allows the quantification of bacterial swimming in a well-controlled environment, for durations of up to an hour and with a temporal resolution higher than the flagellar rotation rates of ~100 Hz. The assay is based on an instrument combining optical tweezers, light and fluorescence microscopy, and a microfluidic chamber. Using this device we characterized the long-term statistics of the run-tumble time series in individual Escherichia coli cells. We also quantified higher-order features of bacterial swimming, such as changes in velocity and reversals of swimming direction