Electric stimulation-guided epidural analgesia for vaginal delivery: A randomized prospective study.

BACKGROUND: The failure rate of epidural anesthesia using the loss of resistance technique is 13-23%. OBJECTIVES: To investigate the efficacy of epidural electric stimulation-guided epidural analgesia in vaginal delivery. STUDY DESIGN: An open label randomized prospective study. METHODS: Laboring women were randomized to two groups: epidural catheter insertion using only a loss of resistance technique or a loss of resistance technique with confirmation by electric stimulation. Catheters in both groups were initially tested with 3 ml of 1% lidocaine and those with any evidence of motor blockade were considered intrathecal. Sensory blockade and an 11 point numerical rating score for pain were assessed 30 minutes after administration of an epidural bolus of 10 ml of 0.22% ropivacaine with fentanyl. Successful epidural analgesia was defined as a decrease of 2 or more in the pain score and a bilateral L1-T10 sensory blockade. RESULTS: Thirty-one patients were randomized to each group. The first 20 patients in each group were enrolled in a pilot study and were also included in the final analysis. One patient in the electric stimulation group was excluded owing to dural puncture by the Tuohy needle. One patient in each group demonstrated motor blockade after test dose and were considered failures. The number (% (95% confidence interval)) of successful cases were 29 out of 30 (97% (85, 100%)) in the electric stimulation group and 24 out of 31 (77% (61, 89%)) in the loss of resistance group (P = 0.053). However, analysis of only patients with absence of motor blockade revealed that 29 out of 29 (100% (92, 100%)) patients in the electric stimulation group and 24 of 29 (80% (63, 91%)) patients in the loss of resistance group had adequate analgesia (P = 0.024). CONCLUSIONS: Although limited by lack of blinding, small study size and inclusion of pilot study data, this study suggests epidural electric stimulation improves the success rate of subsequent labor analgesia.

CO2 during single incisional thoracoscopic bleb resection with two-lung ventilation.

BACKGROUND: CO2 insufflation could provide a better surgical field during single-incision thoracoscopic surgery (SITS) with small tidal two-lung ventilation (ST-TLV). Here we compared the surgical field and physiological effects of ST-TLV with and without CO2 during SITS. METHODS: Patients underwent scheduled SITS bullectomy. Surgery under ST-TLV general anesthesia performed without CO2 (group NC) or with CO2 insufflation (group C). The surgical field was graded at thoracoscope introduction and at bulla resection as follows: good (more than half of the 1st rib visible; bleb easily grasped with the stapler), fair (less than half of the 1st rib visible; some manipulation needed to grasp the bleb with the stapler), or poor (1st rib non-visible; bleb ungraspable). Vital signs, arterial blood gas analysis (ABGA), and mechanical ventilation parameters, postoperative chest tube indwelling duration, length of hospital stays, and complications were recorded. RESULTS: A total of 80 patients were ultimately included. The surgical field at thoracoscope introduction was better in group C (P=0.022). However, at bleb resection, the surgical fields did not differ (P=0.172). The operation time was significantly longer in group C (P=0.019) and anesthesia recovery time was not different (P=0.369). During the CO2 insufflation, the airway pressure was higher in group C (P=0.009). Mean PaCO2 was significantly higher (P=0.012) and mean PaO2 was significantly lower (P=0.024) in group C, but both values were within the physiologically normal range. Postoperative chest tube indwelling duration and length of hospital stays were not statistically different (P=0.234 and 0.085 respectively). Postoperative complication frequencies were similar (12.5% for group NC, 10.0% for group C, P=0.723). CONCLUSIONS: SITS with CO2 insufflation during ST-TLV did not produce a superior surgical field except at the beginning of surgery. CO2 insufflation required more time and resulted in higher mean PaCO2 and peak airway pressure.