High quality labour analgesia using small gauge epidural needles and catheters

An anatomical study of lumbar epidural catheterization

BACKGROUND

We herein provide an analysis of lumbar epidural catheterization, which outlines a detailed anatomical description of the epidural anatomy, and may improve the success rate of neuraxial cannulation.

METHODS

Lumbar epidural catheters were placed in 50 adult embalmed cadavers. After catheterization, the lumbar dura and connecting structures between the epidural space and the vertebral body were separated. The positional relationship between the catheter and the posterior epidural space were observed and photographed.

RESULTS

Amongst the 50 specimens, the epidural catheter curled into a circle in three cases, entered the intervertebral foramen in two cases, and caused epidural venous damage in five cases.

CONCLUSIONS

Meningo-vertebral ligaments exist in the posterior epidural space and connect to the venous plexus, which may contribute to epidural catheter failure, uneven distribution of anaesthesia and epidural hemorrhage. Our study provides anaesthesiologists with a better understanding of the anatomy and may mitigate complications of lumbar epidural catheter placement.

A comparison of two epidural catheter connectors

BACKGROUND

Disconnection of the filter from its catheter is an established problem with epidural analgesia. Previously, it has been hypothesised that the screw cap connector is more prone to disconnection than the clamp connector design. The aim of this study was to test which of two mechanisms connecting the epidural catheter and filter was more prone to disconnection.

METHODS

We recruited 20 consultant anaesthetists. First, each was asked to assemble an epidural set, either B Braun or Portex, in their normal way. Second, each anaesthetist assembled an epidural set, either B Braun or Portex, but was asked if they could improve the security of the connection, whilst avoiding catheter lumen occlusion. Each assembled set was then tested to determine adequacy of catheter connection using a standard protocol. Statistical analysis was performed using the Fisher's exact test.

RESULTS

The strength of the connection of the B Braun epidural set was similar to the Portex set when assembled for everyday practice (mean 1100g; median 1100g; SD 249 vs. mean 920g; median 1050g; SD 603). However, the incidence of inadequate connection was 0 in the B Braun group vs. 5 (25%) in the Portex group (P=0.04). It was possible to improve the reliability of the Portex system, although episodes of weak connection were not eliminated.

CONCLUSIONS

We conclude that the Portex connection system is more prone to disconnection and that connection design is an important consideration when trying to minimise catheter disconnection.

Management of postdural puncture headache in the obstetric patient

PURPOSE OF REVIEW

The treatment of postdural puncture headache remains controversial, largely because it is insufficiently evidence based. With high rates of neuraxial block in the obstetric population likely to continue, postdural puncture headache will remain a primary cause of morbidity and increased duration of hospital stay. This review describes new reports of relevance published in 2006 and until October 2007.

RECENT FINDINGS

New evidence justifies epidural blood patch as the treatment of choice for severe postdural puncture headache, but technical aspects such as optimal timing and volume are less clear. Symptomatic medical management remains diverse, with a multitude of therapies often advocated, despite a lack of scientific support. Reports of misdiagnosis and of complications associated with postdural puncture headache and its treatment emphasize the importance of multidisciplinary management and additional investigation, including radiological imaging, when the clinical picture warrants.

SUMMARY

The key reports in this epoch have shed light on the benefits of careful assessment of postpartum headache and treatment with an epidural blood patch. New management paradigms have been suggested and serious complications continue to be reported.