[Ultrasound-guided regional anesthesia: best practice upper extremities]. / Ultraschallgesteuerte Regionalanästhesie: Best Practice Obere Extremität.

Regional anesthesia of the upper extremities is now part of the standard repertoire of a clinical anesthesiologist. Assigning the correct procedure to the individual needs of the patient is becoming increasingly more difficult due to the wide variety of options. The principle use of regional anesthesiological procedures is hardly ever questioned anymore but it needs to be carefully considered and must be adapted exactly to the case at hand.

Ultrasound guidance for neuraxial analgesia and anesthesia in obstetrics: a quantitative systematic review.

PURPOSE: The aim of this quantitative systematic review was to assess the efficacy and safety of ultrasound-guided neuraxial blocks in obstetric analgesia and anesthesia. MATERIALS AND METHODS: A systematic search for clinical trials investigating the efficacy and safety of ultrasound-assisted neuraxial blocks in comparison to any other technique was performed in MEDLINE, EMBASE, CINAHL and CENTRAL. Relative risks (RR) were calculated for dichotomous data (e. g. number of patients with vascular punctures), and mean differences (MD) were calculated for continuous outcomes (e. g. number puncture attempts), along with the respective 95 % confidence intervals (95 % CI). RESULTS: Six clinical trials (published between 2001 and 2009) including the data of 659 patients satisfied the inclusion criteria. Ultrasound-facilitated neuraxial blocks required a lower number of puncture attempts (MD: -0.92; 95 % CI: -1.11 to -0.74; p < 0.00001) and fewer puncture levels (MD: -0.2; 95 % CI: -0.31 to -0.1; p = 0.0002) in comparison with the more conventional loss of resistance. The success rate with the first attempt under ultrasound guidance in supposedly difficult patients was 71 % in comparison to 20 % using a conventional technique. Patients receiving ultrasound-assisted neuraxial blocks had a lower rate of procedure-related complications (post-dural puncture headache, spinal or vascular puncture). CONCLUSION: There is some evidence that ultrasound guidance may improve the efficacy and safety of neuraxial blocks in obstetrics. If technical difficulties are anticipated, ultrasound may lower the rate of procedure-related adverse events.

Adsorption of sufentanil to epidural filters and catheters.

BACKGROUND AND OBJECTIVE: Stable drug concentrations must be administered to provide adequate patient-controlled epidural analgesia. This study investigated the stability of sufentanil after the epidural delivery system had been flushed with solutions containing the drug. METHODS: Sufentanil citrate, 5 microg mL(-1) was injected through an epidural catheter system into a glass container. The concentrations of the drug leaving the system, in 1 mL aliquots (1-5 mL) were measured using high-performance liquid chromatography. In the same manner, sufentanil samples were analysed after flushing the filter, as well as after priming the filter and catheter. RESULTS: ANOVA for repeated measurements demonstrated that sufentanil concentrations remained constant as long as the catheter had been adequately flushed. However, the concentration of sufentanil in the solution exiting the filter was reduced significantly. Hardly any sufentanil could be detected (0.09 +/- 0.01 microg mL(-1), P < 0.001) in the first 1 mL aliquot (probe) leaving the filter. Altogether, 3 mL sufentanil solution was needed to pass through the filter before the baseline values were restored (P > 0.05). The greatest decrease occurred when the whole epidural delivery apparatus (catheter and filter) was primed; to regain baseline values, as much as 4 mL solution was needed to flush the system. CONCLUSIONS: Sufentanil citrate is adsorbed by the materials used to manufacture systems (catheters, filters) used in epidural anaesthesia. Hence, the epidural catheter system should be primed with sufentanil before connecting it to the patient so as to deliver reliable concentrations.

Stability of a sufentanil-ropivacaine mixture in a glass and a PVC reservoir.

BACKGROUND AND OBJECTIVE: Drug mixtures containing sufentanil may be unstable owing to absorption into the drug reservoirs of patient-controlled epidural analgesia systems that contain polyvinylchloride. The stability of sufentanil in a mixture of ropivacaine 0.2% in a 750 mL reservoir was therefore investigated. METHODS: During simulated epidural infusions of 5 mLh(-1) at 25 degrees C, sufentanil concentrations were measured for 96 h. Samples were taken from the reservoir and from the end of the epidural catheter under the following conditions: into glass or polyvinylchloride reservoirs containing ropivacaine 0.2% with sufentanil 1, 0.75 or 0.5 microg mL(-1); and into polyvinylchloride reservoirs with ropivacaine 0.2% and sufentanil 1 microg mL(-1) which were stored for 4 weeks at 8 degrees C. RESULTS: The different solutions remained stable over the observation period of 96 h. Using the same solutions, independent samples' ANOVA showed no difference in the sufentanil concentrations between the glass and polyvinylchloride reservoirs, or between the polyvinylchloride reservoirs when stored for 4 weeks. Correlations between the concentrations at the different measurement times were extremely high for the reservoir (r(min) = 0.98, r(max) = 1.00) and the catheter end (rmin = 0.86, r(max) = 1.00). CONCLUSIONS: Sufentanil citrate at 0.5-1.0 microg mL(-1) in an admixture of ropivacaine 0.29 for 5 days, which is the usual period for postoperative epidural analgesia, remains stable in a polyvinylchloride reservoir. There is no change in the drug concentration even if the reservoir is stored for 4 weeks at 8 degrees C.