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

The aim of this quantitative systematic review was to assess the efficacy and safety of ultrasound-guided neuraxial blocks in obstetric analgesia and anesthesia.

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).

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).

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.