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Anesthesiologists commonly perform the loss of resistance technique in order to identify the epidural space during neuraxial procedures; however, this technique is subjective and lacks reliability in certain cases. The so-called CompuFlo® technology provides objective information about the position of the epidural needle by means of a pressure curve and acoustic signals. The technology was introduced several years ago and was evaluated in several trials, which showed promising results. The purpose of the present publication is to report on the first experiences with the CompuFlo® technology in German-speaking countries. A series of 24 epidural procedures using the CompuFlo® device was carried out in routine daily practice. The epidural space was successfully identified in 23 cases. Conversion to the conventional loss of resistance technique was performed during the initial cases in a prolonged procedure. The CompuFlo® technique is considered to be a promising technology, which might help to reduce complications after epidural anesthesia, e.g. postdural puncture headache.

Perioperative pain therapy using an epidural catheter is the standard operating procedure for numerous surgical interventions. The necessity of initiating anticoagulant therapy in a patient with an epidural catheter requires a careful weighing up between thromboembolic complications and epidural hematoma. The case presented here of a 47-year-old female patient who was operated on for mastectomy with a latissimus dorsi myocutaneous flap demonstrates a possible solution to this dilemma. The patient sustained a perioperative ST elevation myocardial infarction treated with drug-eluting stents while undergoing epidural pain therapy. By using the short-acting antiplatelet drug tirofiban over a time period of 7 days the gap for dual antiplatelet therapy was reduced with the help of specific platelet aggregation assays to a time frame of a few hours to minimize the risk of stent thrombosis. The epidural catheter was removed without complications under consideration of the current recommendations for regional anesthesia and antithrombotic agents.

Peridural anaesthesia needles (PDA) do not only differ in calibre or gauge but also vary in the design of the needle tip, which shows a special configuration to place a catheter in the epidural space. A laboratory model was performed to determine the influence of different types of virgin epidural needles concerning their path through tissue. In an additional test run we analysed the influence of a previous use on the path through tissue. We investigated 16 G and 18 G Tuohy needles for epidural anaesthesia and two different 18 G Tuohy needles for combined spinal-epidural anaesthesia. The experiments were performed in a standardised way using a precision drill press in order to make the test independent of the investigator. The test tissue was selected because of its close similarity to human tissue of the lumbar region. Every needle tested revealed a distinct deviation even after a 6 cm passage through the test tissue and regularly deviated away from the concave side of the needle tip. The comparison of the CSE needles tested revealed a significant deviation from the axis due to differences in cross-section and configuration of the needle tip. As expected, the average deviation of PDA needles depended on the diameter. No differences in the degree of deviation for virgin needles compared to previously used needles could be found. Thus, more than one application of the same needle in one patient is considered to be safe as long as the needle is not deformed in any way.

Besides pain management in obstetric patients epidural anaesthesia plays a major role in the perioperative setting. Especially the technique of thoracic epidural anaesthesia (TEA) provides better postoperative analgesia when compared with systemic pain therapy. TEA is associated with improved outcome in high-risk patients and patients undergoing extensive surgery. An acute pain management service is required to guarantee high effectiveness and a low complication rate. TEA is an important part of a multimodal perioperative concept, especially in fast-track surgery, which means advantages for patients outcome and hospitals economics.

Background: The purpose of this study was to investigate whether there is a risk of epidural catheter damage during the advancement of the spinal needle through an epidural needle in clinical use., Methods: A total of 100 catheters (50 from CSE kits with a pencil-point type spinal needle and 50 from CSE kits with a Quincke type spinal needle) which had been used for routine CSE blocks were microscopically examined for any defects within the first 150 mm of the catheter. Additionally 10 unused new catheters were investigated., Results: Among 10 unused catheters 5 slight scratches were found, 92 out of 100 used catheters did not show any signs of use or scratches, 7 showed some signs of use and longitudinal scratches whereas another 1 showed a moderate scratch of less than 25% of the wall thickness. There was no difference in the prevalence of scratches between the CSE kits with pencil-point type spinal needles compared to those with Quincke-type spinal needles., Conclusion: The CSE technique with either pencil-point type or Quincke-type spinal needles for subarachnoidal punctures was safe and showed no relevant epidural catheter damage.

A rare though extremely harmful complication in neuraxial anaesthesia is an epidural hematoma which can be associated with deleterious consequences for the patient, e. g. persistent paraplegia. The risk of epidural haematomas after neuraxial blockade is dependent on abnormal anatomy of the spine, difficult and multiple punctures and coagulation disorders. Especially when patients undergo therapy with anticoagulants like low molecular heparin or platelet inhibitors (tyclopidine) or a combination of them, the indication for neuraxial blockade must strictly outweigh risk of spinal bleeding. In this context, the precautions and contraindications are the same for spinal puncture and catheter insertion as for catheter removal. We describe the case of a patient who underwent emergency coronary angioplasty in combination with coronary stent implantation due to acute postoperative myocardial infarction following knee replacement in continuous epidural anaesthesia. Under the symptoms of a beginning local infection at the puncture site the epidural catheter had to be removed in spite of ongoing antithrombotic therapy. A possible management of such cases is discussed with regard to risk minimization.

We describe a case of postoperative subdural dislocation (between dura and arachnoidea spinalis) of an epidural catheter. After 24 h of normal functioning of the catheter, the injection of 5 ml lidocaine caused an extensive unilateral sensory block including the cranial nerves. X-ray control excluded an epidural or intrathecal position of the catheter. A delayed dislocation of the epidural catheter into the subdural space can occur but this complication only usually becomes evident after injection of a normal dose of local anaesthetic into the catheter and can have catastrophic consequences. The safety of patients can only be guaranteed if epidural catheters are managed solely by professional anaesthesiological personnel. Anatomy, mechanisms of complications and clinical differential diagnosis are discussed.

The needle type introduced by Edward Tuphy for continuous spinal anaesthesia in 1944 is still used as the standard instrument for epidural anaesthesia up to the present day. Puncture of the dura and severance of the epidural catheter are the typical, though fare, complications of this procedure, giving rise to most of the actions brought for damage suffered during obstetric anaesthesia. The cerebral spinal fluid loss caused by thick needles can have serious consequences, including subdural and intracranial haematoma, cranial nerve pareses, labyrinthine hearing impairments and pneumocephalus. Special Sprotte needle for catheter introduction. In spinal anaesthesia and lumbar puncture the Sprotte needle has proven a very suitable instrument for the CSF loss syndrome and, to a large degree, post-spinal headaches. To adapt the atraumatic properties of this needle point for epidural anaesthesia the needle has been equipped with a plastic ramp to direct catheter insertion, and the opening geometry has been slightly modified for epidural application (see Fig. 1). The lateral catheter channel projects into the base of the needle point, which is thus shortened, and the edges of the needle opening are rounded so that the catheters cannot be severed. This needle bears the type designated "Special Sprotte needle" (EP no. 271715, USP no. 4842585). Needle diameter and application fields. The 1.1-mm (19.5 G) needle with 23-G catheter was introduced for epidural anaesthesia and continuous plexus anaesthesia at the Würzburg University Hospital and has proven itself in routine clinical practice. A 20-G version is being tested with a 25-G catheter for continuous spinal anaesthesia at several centers in USA, because finer spinal catheters are not permitted there by the FDA. For continuous spinal anaesthesia this needle has been available without the modified opening geometry since 1989 in sizes 22 G and 24 G and is wide by used in Europe. CSE technique with special and standard Sprotte needles. Spinal analgesia or anaesthesia) can be performed with the special needle and 123-mm-long 27 G or 29 G standard Sprotte needles before placement of the peridural catheter.

26 days past an obstetric catheter epidural anesthesia a subdural haematoma right fronto-temporal was diagnosed and relieved by operation in a primipara of 19 years of age. Already several days after the delivery the patient was suffering recurrent headaches, at first misinterpreted as post-spinal headaches. Weeks later a cranial computer tomography lead to the right diagnosis. Although the occurrence of a subdural haematoma after catheter epidural anesthesia is extremely rare, untypical headaches following spinal, epidural or caudal procedures, should call your attention towards this complication. Because of the pressing mechanisms during childbearing, delivering mothers run the risk of a subdural haematoma.

Unlabelled: In a prospective study we compared the spread of sensory blockade in epidural anaesthesia with and without Micropore filter., Materials and Methods: A total of 32 patients undergoing varicose vein stripping under epidural anaesthesia were randomly assigned to two groups of 16 each. Bupivacaine 0.75% and POR 8 (0.1 IU/ml) were administered by means of a constant-velocity perfusor. In group A a Micropore filter was inserted between the perfusor syringe and the epidural catheter. In group B the epidural catheter was connected to the syringe without the filter. The puncture was performed at the L3-4 interspace with the patient in a sitting position. An epidural catheter was advanced 3 cm cephalad. Using the pin-prick method, the sensory level of the blockade was tested 5, 7, 10, 15, 20 and 30 min after injection of the local anesthetic solution. Statistical evaluation was performed with the t-test for unpaired samples. RESULTS. After 10 min the spread of analgesia was 5.75 +/- 1.26 segments in group A and 8 +/- 1.89 segments in group B; after 15 min it was 7.06 +/- 1.62 segments and 9.56 +/- 1.54 segments; after 20 min, 7.87 +/- 1.62 segments and 10.62 +/- 1.45 segments; and after 30 min 8.12 +/- 1.66 segments and 11.12 +/- 1.45 segments in group A and B, respectively. At any time sensory blockade was higher in group B (without Micropore filters) than in group A. The mean difference between the two groups amounted to 2-3 segments. The differences were significant at any time (P less than 0.001). These results show that the use of a Micropore filter in epidural anaesthesia leads to a reduced spread of sensory blockade. In our own examinations we found lowering of the pressure of the local anaesthetic solution that passes through the Micropore filter compared with the pressure of the solution injected without the filter. This seems to be the reason for the reduced spread of sensory blockade. Using these filters the onset of analgesia is delayed, and a given spread of analgesia needs a larger dose of local anaesthetic and is thus accompanied by a higher toxicity.

We report a patient who was given continuous epidural anesthesia due to painful contractions during delivery of a child after intrauterine fetal death. Placement of the catheter and repeated reinjections were carried out without problems, however, during withdrawal of the catheter it could only be pulled 1-2 cm until there was enormous resistance. An X-ray film showed knotting of the catheter in the epidural space. Firm pulling finally allowed complete withdrawal of the catheter. Insertion of the catheter too far into the epidural space initially must be considered as a possible cause. As this complication rarely occurs, we consider this case worth reporting.

The availability of very fine-bore, long spinal needles (28/10 Ga) has stimulated a new wave of interest in the technique of combined spinal-epidural anesthesia. The original double-puncture technique has progressed due to special combination needles to the current spinal-needle-through-epidural-needle technique. The availability of adapted Tuohy needles, special combination sets, and long spinal needles indicates a lack of standardization. An appropriate introduction technique via Tuohy needle allows identification of the anatomic landmarks and contributes to successful anesthesia. The spinal component allows a rapid onset and intense analgesia with appropriate muscle relaxation. The epidural catheter allows the administration of agents into the epidural space as well as optimization and prolongation of analgesia in the postoperative phase. Confirming the position of the epidural catheter introduced after spinal anesthesia has been established remains a matter of concern.

Continuous epidural anesthesia (CEA) is generally accepted as a routine method of regional anesthesia while there has been only limited application of continuous spinal anesthesia (CSA), due mainly to a lack of adequate spinal catheters. With the introduction of a new, ultra-thin spinal catheter (32 G) inserted via a thin puncture needle, some of the complications reported after CSA can be eliminated. We studied CSA versus CEA in lower-extremity operations. METHODS. We evaluated 33 patients in a prospective, randomized study. All were comparable with respect to age, anesthetic risk (ASA II-III), and pre-existing diseases. The only exclusion criterium was the presence of a coagulation disturbance. The CSA group consisted of 17 patients (mean age 75.5 +/- 0.1 year); 26 G puncture needle and 32 G catheter were used. The CEA group consisted of 16 patients (mean age 73.8 +/- 11.0 years); an 18 G puncture needle and 22 G epidural catheter with a stylet were inserted with the loss-of-resistance technique. Both catheters were placed with the patient in a sitting position and left in place for 24 h in order to administer local anesthetics (LA) for postoperative analgesia as required. Hemodynamic parameters-mean arterial pressure (MAP) and heart rate (HR)-were compared in each group at 5-min intervals for 30 min after administration of local anesthetic and at 10-min intervals during the operation. Additionally, the ECG, pulse oximetry, respiratory rate, diuresis, and blood gases were monitored. After placement of the catheter, patients in the CSA group received 1.9 ml (+/- 0.2) bupivacaine HCl 0.5%. Patients in the CEA group received 12.6 ml (+/- 2.5) bupivacaine HCl 0.5%. For statistical evaluation of the data we used mean values, standard deviation (+/-), the Kruscal-Wallis procedure, and Student's t-test for unpaired data. P less than 0.05 was considered significant. RESULTS. The mAPs in the CSA group generally remained lower than those of the CEA group. However, over the course of the operation as well as after repeated injections, the difference between the two groups decreased. Only at 5 min after administration of the initial dose was a statistically significant difference in blood pressures between the two groups observed. A clinically relevant, rapid decrease in blood pressure due to relatively high doses of LA was seen in 1 case in each group. The first reinjection of LA after the initial dose was after 1.9 h in the CSA group (bupivacaine HCl 0.5% 1 +/- 0.3 ml) and after 1.8 h in the CEA group (bupivacaine HCl 0.5% 4.5 +/- 1 ml). The total dose of bupivacaine in the CSA group was 0.18 ml/kg per hour versus 0.8 ml/kg in the CEA group. No post-dural puncture headache was observed in the CSA group. DISCUSSION. The catheter designed for CSA is easy to use, although because of its small diameter a certain manual dexterity is required. In addition, CSA resulted in a more rapid onset of action and more pronounced sensorimotor blockade than did CEA. Hemodynamic alterations and side effects were comparably low in both groups.

The purpose of the investigation was to correlate the distance from the skin to the flaval ligament with the individual data of patients such as bodyweight, height, sex and age with the aim of predicting the depth of insertion of the needle. In a retrospective study we examined 448 patients (217 men and 231 women). In the anaesthetic records the depth of insertion of the needle was noted together with the patients' personal data. Evaluation of the material showed that there is no correlation of statistically significant relevance between the depth of insertion and the bodyweight and age of the patient, but there is a correlation between depth of insertion on the one hand and the variables bodyweight, overweight and the quotient body height/weight on the other. This correlation showed a somewhat higher significance in women than in men. The correlation can be expressed in a formula like y = K + fx, whereby for the relation between depth of insertion and body weight the equation for men is y = 1.87518 + 0.02761x. The equation for women is y = 2.23985 + 0.03559x. With these formulae a rough prediction for the depth of insertion can be made, with x representing the bodyweight and y the expected depth in cm. The measured values fluctuated between 3.5 and 7.4 cm in the 217 men, with the medium value at 4.08 cm. In the 231 women the measured values fluctuated between 3.3 and 6.9 cm with the medium value at 4.67 cm.

Four cases of unilateral spread of epidural anesthesia are presented. All were documented by X-ray epidurography. In two patients the catheter had passed immediately into one of the intervertebral foramina so that the local anesthetic had almost totally been injected into the paravertebral space. In the third and fourth cases a membrane was present in the dorsal epidural space that had prevented bilateral spread of the local anesthetic. This article discusses the fact that strands of the dorsomedian connective tissue band of the lumbar epidural space can cause catheters to coil up, be diverted, and not infrequently be directed into the next intervertebral foramen. These strands sometimes form a dense membrane, which together with the plica mediana of the dura mater prevent symmetrical spreading of epidurally injected fluids. When informing a patient about epidural anesthesia, the anesthesiologist should mention that anatomical variations in the epidural space can cause epidural anesthesia to spread unilaterally.

Unlabelled: The aim of this study was to determine at which lumbar spinal level the tips of different epidural catheters may be located following insertion through cranially directed Tuohy needles. Previous studies varied with respect to materials and methods and may have left the false impression that different types of catheters are necessary or actually more advantageous for particular needs., Materials and Methods: One hundred seventy-five trauma patients scheduled for surgery on their lower extremities received continuous epidural anesthesia. With the patient in a sitting position, a midline lumbar puncture was made and one of six different plastic catheters advanced 5 cm beyond the tip of the Tuohy needle. Postoperatively the catheters were filled with Iopamidol and ap X-rays taken of the lumbar spine. The catheter tips were declared to be "cranial" if they were more than 2 cm above, "caudal" if they were more than 2 cm below, and "equal to" if they were within 2 cm of the puncture site., Results: Of the 175 documented catheter tips 47.7% assumed a cranial position, 9.2% were in a caudal position, and 43.4% remained within the level of insertion. A statistical analysis comparing catheter tip location among the six epidural catheter models tested did not reveal any significant differences., Discussion: In a clinically controlled study based on the Tuohy principle of inserting catheters through a needle with a Huber point, different epidural catheter models were inserted into the lumbar epidural space and their locating radiologically documented. It was shown that 52% of the epidural catheters that had been advanced 5 cm into the lumbar epidural space through a cephaled-directed Tuohy needle did not reach the intended spinal level cranial to the puncture site. The results are similar to those of earlier studies, which were not systematic and involved a variety of methods and materials. One reason for the unreliable ascension of the catheter tips may be the many structures within the epidural space which may dislodge and divert the catheters during advancement. In addition, it has sometimes been observed that a change in the patient's position may cause a spinous process cranial to the puncture site to exert pressure and traction on the catheter, partially dislodging it. It must thus be concluded that the use of a Tuohy needle cannot guarantee cranial ascension of an epidural catheter in the lumbar epidural region.

Two cases of secondary subarachnoidal dislocation of lumbar epidural catheters are reported. The first catheter was placed, tested, and injected with 20 ml local anesthetic in order to achieve intraoperative anesthesia up to the T4 level. On the 2nd postoperative day the test dose produced paralysis of the lower extremities; liquor now could be aspirated. The second catheter had been introduced into the epidural space immediately after injection of 15 ml local anesthetic through the needle. Use of this catheter for postoperative analgesia led to total spinal anesthesia in spite of negative aspiration and test dose prior to injection of 7 ml local anesthetic. Implications of these two cases concerning placement procedures and monitoring during reuse of catheters placed some time before are discussed.

A cannula system for epidural puncture is presented, that has been developed in order to prevent the risk of dural puncture and nerve damage and allows the epidural catheter to be withdrawn without the risk of tearing or cutting off the end. The cannula system ("Mancao-cannula") consists of a sharp outer and a blunt inner needle with a lateral aperture. First experiences in 400 epidural anaesthesias using the Mancao cannula are reported.

Disposable needles for epidural single-shot and catheter techniques are being marketed increasingly by different firms. As a result of our experience, the basic requirements of each of the component parts in the needle assembly are outlined. It is clear that the materials used to date are failing in some requirements and we assume that the manufactures have possibly not taken account of the suggestions of practicing anaesthesists.

An epidural catheter inserted at the height of L2/3 could not be removed after spontaneous delivery of a healthy boy, manual extraction of the placenta and fixing the episiotomy. X-rays (lumbar spine a-p and lateral) were taken in order to visualize the epidural catheter's site. The catheter could only be recognized on the a-p but not on the lateral film. It was possible to recognize a foreign body in the ultrasonic study. The exact site of the catheter could not be determined. Continuous pulling in various positions (bend over, stretch and lateral position) could not remove the catheter. A consultant neurosurgeon tried also in vain to remove the fixed catheter. In a final trial pulling hard the catheter broke. The indication for operative extraction was given. Finally the catheter fixed in the ligamentum flavum building a loop and a tight knot in the epidural space could be freed up and removed surgically.

We report on a 57 year old woman, who suffered from an inadvertent intravascular injection of bupivacaine via a perforating epidural catheter. At the end of the epidural injection she showed symptoms of toxicity caused by the local anaesthetic. Venous blood dripping out of the epidural catheter and central venous blood were sampled simultaneously and analysis of plasma levels of bupivacaine were performed.

We tested a new epidural catheter, which is made of a stainless steel spiral (similar to an anode endotracheal tube) covered with a fluorpolymer. This catheter was tested in 15 patients who were administered lumbar epidural anaesthesia for pain relief during labor. We also have information on the evaluation of this catheter in about 100 patients from the obstetric anesthesia service, Stanford-University Medical Center. The main advantage of this catheter is, that it does not kink. The disadvantages are: 1. catheter leakage either at the skin interface or just below the injection port particular after prolonged usage, 2. difficult or impossible injection if the catheter injection port is screwed on too tight which requires cutting the catheter (not recommended by the manufacturer), 3. a 17 gauge rather than a 18 gauge epidural needle is recommended and 4. the high price of the catheter.

Following anaesthesia the tips of 105 epidural catheters were investigated for aerobe and anaerobe bacteria. In one case aerobe germs (staphycoccus epidermidis) and in three cases anaerobe germs (propioni-bacteria were isolated. In two further cases aerobic growth was suspected but not confirmed in sub-cultures. The contamination rate was therefore 0.9% aerobe and 4.8% by anaerobe bacteria. Even in the face of a clinically uncomplicated course the presence of bacteria on the catheter tip is considered to be a potential risk for infection. As a preventive measure the skin disinfection procedure was changed and the disinfectant is left for sic minutes instead of three minutes.

Peridurally administered analgetica provide pain relief and may also be used for treatment of chronic pain of malignant origin. Compared to injection via externalized catheter single-shot injection via implantable reservoir and peridural catheter offers some advantages. The authors have used this method first 1985. Technique of implantation and preliminary results of this method are presented as a case report.

In general surgical wards postoperative epidural analgesia was performed in 286 patients consecutively. Epidural catheters were kept in place 8.3 days in the average with a minimum of 24 h and a maximum of 45 d. Bupivacain was applied as a 0.25% solution with an average daily dose of 75-250 mg and single doses of 12.5-50.0 mg. An uncomplicated course was noticed in 250 cases, 19 cases showed haemodynamic, 7 cases neurologic and 10 cases technical complications. Severe decrease of systolic blood pressure more than 30% of the control value was due to postoperative haemorrhage, to anaemia with Hgb-concentration lower than 11 g/dl or to untreated chronical hypertension. On the basis of these observations a list of conditions has been drawn up which should be adhered to when epidural catheters are used for postoperative pain relief in normal wards.

Implantable devices (implanted pump/implanted catheter and port) are recommended for continuous epidural application of opiates or local anaesthetics in order to reduce hygienic problems during long term epidural medication. No signs of contamination could be found during bacteriologic culture of residual volumes of 30 patients treated with epidural drug delivery systems and of samples collected during an in vitro investigation (incubation of filled external pump systems at body temperature/storage of syringes with a premixed solution of opiate and local anaesthetic for repeated epidural bolus application). As demonstrated in a case report prophylactic antibiotic coverage prior to implantation may be necessary in patients with a preexisting susceptibility to infection. The concentrations of morphine (radioimmuno-assay) and of bupivacaine (gas-solid chromatography) within the reservoir were stable during clinical therapy as well as during the in vitro experiments.