During t h s World Congress of Anacr;thcsiology in 1968 a prcss confcreiicc was held on the relief of pain i n labour by means of regional block. A television programme followed and this resulted in an increased demand by women for efficient pain relief during childbirth. Unfortunately owing to inadequate facilities in some obstetric hospitals many women were disappointed. or what was worse, suffered at the hands of inexperienced anaesthetists who tried to meet their demands. The techniques of extradural and of caudal block are specialised and not to be embarked upon lightly. In this paper a search has been made in the world literature for possible complications occurring not only in obstetric cases but in surgical cases also. and over 350 articles have been scrutinised. In addition a comparison has been made with these findings and those of the author in performing 4,000 blocks during the last 25 years. At the outset it must be emphasised that although in many papers complications are mentioned, frequently their incidence is not given. Therefore only those papers where definite figures are given are included in this analysis. This results in a discrepancy in the total number of cases quoted for any given complication, for often complete figures for every complication are lacking. References have been listed only in special circumstances, as the inclusion of all that have been read might well exceed the total length of this paper. Complications may be divided into those following a single injection into the extradural space in the lumbar or thoracic region, those following a caudal block and those consequent on the introduction of a catheter. The results are summarised in tables 1 and 3 and the author'sexperience is given in table 2.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2044.1969.tb02909.x

An analysis of the complications of extradural and caudal block.

Background The distribution of solutions injected into the epidural space has not been determined. The author therefore examined the site of catheter tips and the spread of contrast material in the epidural space using computed tomographic (CT) imaging in patients receiving successful epidural analgesia. Methods Lumbar epidural catheters were placed in 20 female patients by a midline technique. Anesthetic effect was determined by motor and sensory examinations during analgesic infusion. CT images were obtained for identification of the catheter tip and after radiographic contrast injection of 4 ml and then an additional 10 ml. Results Catheter tips were most often found lateral to the dura in the intervertebral foramen. In these subjects with normally functioning epidural analgesia, there was remarkable interindividual variability in patterns of spread, including various amounts of anterior passage, layering along the dura, and compression of the dura creating a posterior fold. Accumulation becomes more symmetric with increasing injectate volume. Spread through the intervertebral foramina was seen in all subjects. Air and fat in the region of the catheter interfered with solution spread in three subjects, but only over a limited area. Asymmetry in anesthetic effect was attributable to catheter position. No substantial barriers to solution spread were observed. Conclusions A variety of catheter tip positions and patterns of solution spread underlie normal epidural anesthesia. Non-uniform distribution of injectate is common and is compatible with uniform anesthesia. Posterior midline structures play a minimal role in impeding distribution of injectate. A far lateral catheter position is a more common cause of asymmetric block than anatomic barriers to solution spread.

Epidural Catheter Tip Position and Distribution of Injectate Evaluated by Computed Tomography

Complications can occur during epidural placement for women in labor. As many as 23% of epidural anesthetics may not provide satisfactory analgesia. The cause of this may be technical. This study was undertaken to determine the optimal distance that a multiorifice catheter should be threaded into the epidural space to maximize analgesia and minimize complications. One hundred women in labor were enrolled in this prospective, randomized, and double-blind study. Patients were randomly assigned to have the epidural catheter threaded 3, 5, or 7 cm into the epidural space. After placement of the catheter and administration of a test dose with 3 mL of 0.25% bupivacaine, an additional 10 mL of 0.25% bupivacaine was administered in two divided doses. Fifteen minutes later, the adequacy of the analgesia was assessed by a blinded observer. We found that catheter insertion to a depth of 7 cm was associated with the highest rate of insertion complications while insertion to a depth of 5 cm was associated with the highest incidence of satisfactory analgesia. For women in labor who require continuous lumbar epidural anesthesia, we recommend threading a multiorifice epidural catheter 5 cm into the epidural space.

The Optimal Distance That a Multiorifice Epidural Catheter Should Be Threaded into the Epidural Space

Combined spinal epidural (CSE) block with the needle-through-needle technique has become increasingly popular during recent years. However, the risk of epidural catheter penetrating dura mater through the hole made by the spinal needle (migration) is a major concern. In 15 fresh cadavers a percutaneous epiduroscopy technique with a rigid epiduroscope and video recording was used to assess the risk of catheter migration when a CSE block is performed. The experimental sequence included (a) one dural hole made by the spinal needle, (b) multiple (five) dural holes made by the spinal needle, and (c) a dural hole made by Tuohy needle. Twenty-four experimental sequences were performed in the lumbar region. Four sequences were failures due to technical problems. In the remaining 20 cases, the anatomic structures in the epidural space were recognized easily. The epidural space appears to be only a potential space, kept open either by epiduroscope or by repeated injections of air or saline. The dural holes made by Tuohy and spinal needles, and the ease of difficulty of catheter penetration through these holes, were clearly visible. Extensive tenting of the dura was seen in all subjects. It was impossible to force an 18-gauge epidural catheter through the dural hole after a single dural puncture made by a 25-gauge spinal needle. After multiple (five) dural punctures with the spinal needle, the epidural catheter penetrated the perforated dura in 1 of 20 cases. The epidural catheter penetrated the dural hole made by the Tuohy needle in 9 of 20 cases. The distribution of fat, rather than any dorso median connective tissue band, influences the course of epidural catheter in epidural space.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk of catheter migration during combined spinal epidural block: percutaneous epiduroscopy study.

The purpose of this study was to investigate the incidence of technical problems encountered when performing continuous spinal anesthesia and the influence of catheter tip position on block height following injection of a hypobaric spinal anesthetic. Twenty-nine elderly patients undergoing hip surgery were studied. Lumbar puncture was performed with an 18-gauge Tuohy needle at the L3-4 (or L2-3) interspace. Threading was defined as easy if a 20-gauge catheter was inserted on the first try, 3-4 cm cephalad. Threading was considered difficult if cephalad insertion of the catheter was impossible on the first try; the Tuohy needle was then rotated with its bevel facing caudally, the catheter inserted for 1-2 mm, and the needle turned back cephalad together with the catheter partially threaded, for further cephalad insertion up to 4 cm. All patients received 7.5 mg of hypobaric bupivacaine or tetracaine in the lateral decubitus position and sensory levels were determined by pinprick. After surgery all catheters were injected with radiographic dye and examined by radiograph for verification of position. The determination of the level of lumbar puncture was falsely judged in 59% of cases, the puncture being performed 1 or 2 spaces higher than assumed. Although threading difficulties were encountered in 4/28 cases, there was a 100% success rate in catheter insertion. One catheter displacement into the epidural space was noted. Twenty of twenty-eight catheters took a cephalad direction, 6 remained coiled in a horizontal position, and 2 took a caudal direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Phyllis A. Bagdi

Papers

The position of plastic tubing in continuous-block techniques: an x-ray study of 552 patients.

Accumulation of mepivacaine hydrochloride during caudal block.

Tabulation of anesthetic data: an improved system.