Regional-Anaesthesie最新文献

Experience with anesthesia for cesarean sections in a small obstetric and gynecology clinic attached to a general hospital is reported. The course of cases and the particular circumstances are described. During a period of 11 years 721 cesarean sections were performed, 643 (90%) under hyperbaric spinal anesthesia. The remaining operations were performed under general anesthesia. The distribution of elective and emergency cases to the different anesthetic methods is shown. In the early years size G22 needles where most frequently used, while later size G25 was used. The average extent of anesthesia with spinal anesthetic agents was to T 6.2 +/- 1.4. Some indications for intubation anesthesia and special features of spinal anesthetics are listed. The Apgar scores were 8.3 for 1 min and 9.5 for 5 min. In contrast to the patients operated on under general anesthesia, the majority of the patients treated during spinal anesthesia received (prophylactic) hypotensive treatment. There were no severe complications or deaths related to anesthesia. Some important points related to spinal anesthesia for cesarean sections are mentioned. The results show that with attention to detail and observation of correct procedures by qualified anesthetists, the vast majority of cesarean sections can be done very successfully under spinal anesthesia.

Ropivacaine is the (S)-enantiomer of 1-propyl-2',6'-pipecoloxylidide. In terms of its physicochemical properties, it is a long-acting local anesthetic (molecular weight of the base 274, pKa 8.07, protein-binding 92%). It shows a selective action on A delta and C fibers. This may be attributable to its relatively low partition coefficient (6.1 in n-heptane). The subcutaneous and intravenous acute toxicity (LD50) is lower than that of other long-acting local anesthetics. Because of its vasoconstrictor potency, its use as a vasoconstrictor-free solution is of particular interest.

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.

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 patient suffering from intensive perianal pain due to recurrent rectal cancer, not controllable by systemic analgesics, was treated by continuous epidural morphine for a period of 8 months. Satisfactory pain relief was achieved although sometimes problems arose with the permeability of the epidural catheter. As a reason for increased resistance, the literature mentions nonspecific foreign-body reactions next to the catheter. In our patient, tumour infiltration into both the lumbosacral plexus and the epidural space leading to compression of the catheter could not positively be excluded. At autopsy an unexpected obstruction of the catheter by epidermis was observed. It could be demonstrated that pieces of epidermis may enter the catheter, bypassing the bacterial filter of the port, and can then clog the tip of the catheter.

Ten intensive care patients and five healthy volunteers each received a bolus injection of lidocaine HCl (100 mg, 2%) over an injection period of 5 s. After 0.5, 1, 2, 4, 8, 15 and 25 min arterial, central venous and peripheral venous blood samples were collected. In four of the volunteers, arterial and central venous samples were also taken about 10 s after the end of injection. The fluorescence polarization method by means of the Abbott-TDx system was used, and plasma concentrations of lidocaine were determined. The measurements showed that lidocaine levels in central venous plasma 10 s after the end of administration were higher than those in arterial plasma. By 30 s after administration the opposite situation had developed, so that arterial concentrations were higher than those in central venous plasma. This relation did not change throughout the study, though the two levels became closer, as is shown by the ratios (Table 3, Fig. 2). Concentrations in peripheral venous plasma increased more slowly but remained far below those in arterial and central venous plasma, at least for the first 8 min. After 15 min lidocaine levels were almost the same in all three samples. During the entire study there were no ECG changes, and neither heart rate nor blood pressure showed any significant deviation from the values obtained at the beginning. The volunteers had minor toxic manifestations, such as dizziness, tinnitus and a metallic taste in the mouth; one person had a sensation of pressure in his chest, which improved following oxygen administration.(ABSTRACT TRUNCATED AT 250 WORDS)

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.