Abstract: Epidural anaesthesia using the loss of resistance to saline technique, without air, was successfully performed in a 65-year-old man scheduled for elective vascular surgery of the right leg. Epidural catheterisation was uneventful. Fifteen minutes after the initial dose of plain 0.5% bupivacaine, the patient experienced severe pain in his lower abdomen and legs which coincided with a supplementary injection of 2 ml bupivacaine and 50 μg fentanyl, and a change from the lateral to the supine position. General anaesthesia was induced and CT and MRI scans were performed showing trapped air in the epidural space at the L4 level causing compression of the thecal sac. After excluding other causes, the spontaneous entry of air through the Tuohy needle was thought to be the most likely explanation for this complication. The patient recovered uneventfully.

Abstract: UNLABELLED Using the single level needle-through-needle technique for combined spinal-epidural anesthesia (CSE) may introduce very fine metal particles abraded by the spinal needle from the inner ground edge of the Tuohy needle into the patient Either the local anesthetic administered epidurally or the peridural catheter may also pass intrathecally through the hole in the dura made by the spinal needle To examine these concerns, the needle-through-needle technique was simulated in an in vitro model (18-gauge Tuohy needle; 27- or 29-gauge Quincke needle) The presence of abraded metal particles was identified by atomic absorption spectrography (AAS) The needles were then examined under an electron microscope Metal particles could not be identified by using AAS in the needle-through-needle technique after normal clinical use, nor could traces of use be revealed by using an electron microscope to examine the Tuohy needle With intentionally rough handling and caudal orientation of the spinal needle tip, minimal scratches could be seen by using an electron microscope, but there were no metal particles detected by AAS In an anatomical preparation, the possible passage of the epidural catheter anesthetic through the dural puncture hole into the cerebrospinal fluid compartment was investigated endoscopically Neither passage of dyed epidural local anesthetic nor penetration of the epidural catheter into the cerebrospinal fluid compartment could be demonstrated by endoscopy We conclude that the needle-through-needle-technique is an acceptable way of performing CSE anesthesia Endangering the patient by an unintentionally intrathecal misplacement of the epidural catheter seems to be very unlikely based on our in vitro model if small spinal needles (27- or 29-gauge) are used IMPLICATIONS Atomic absorption spectrography shows no contamination of the intrathecal compartment by abraded metal particles from the Tuohy needle by combined spinal-epidural anesthesia with the needle-through-needle technique In vitro, neither passage of dyed epidural local anesthetic nor penetration of the epidural catheter into the cerebrospinal fluid compartment could be demonstrated by endoscopy

Abstract: Purpose: Previous experience has suggested that the insertion of an epidural catheter becomes easier when the patient takes a deep breath. The purpose of this study is to investigate the effects of respiration on the epidural space. Methods: We examined the epidural space using a flexible epiduroscope in 20 patients undergoing thoracic epidural anesthesia. A 17-gauge Tuohy needle was inserted using the paramedian technique and the loss-of-resistance method with 5 ml air. The epiduroscope was introduced into the epidural space via the Tuohy needle. Each patient was requested to take a deep breath when the epiduroscope was positioned at the needle tip and at approximately I0 cm cephalad from the needle tip within the epidural space. The changes in the epidural structure during deep breathing at each site were then measured. ~..~I~: In 80% of the patients, fatty tissue occupied the needle tip. Through the patients' maximal inspiration, the fatty tissue moved and a visible cavity expanded at the needle tip. Cross section area of the visible cavity at the needle tip was greater at the maximal inspiratory level than at the resting expiratory level: 12. I _-z- 6.7 % vs 2.8 --- 2. 1% (mean --- SD, P < 0.0001). In all patients, the visible cavity within the epidural space, which had already been expanded by injected air, became more expanded after maximal inspiration. Cross section area of the visible cavity at the I 0 cm cephalad position was greater at the maximal inspiratory level than at the resting expiratory level: 20,6 --+ I 0.0 % vs 7.0 ___ 5.3 % (P < 0.000 I). Conclusion: Epiduroscopy showed that deep breathing expanded the potential cavity of the epidural space. We suggest that the changes in the epidural structure during deep breathing may assist in the insertion of an epidural catheter.

Abstract: With reference to the letters in the July issue (Anaesthesia 1999; 54: 703±7), I should like to express my support for the views of Dr Cartwright concerning dental anaesthesia. The time has surely come to call a halt. It is now almost exactly six months since, after more than 30 years of dental anaesthetic practice, and approximately 15 000 anaesthetics, I administered my last `chair' anaesthetic. The dentists I worked with decided to call a halt, partly due to adverse publicity and partly to changes in the fee structure. I had no regrets since I have felt, increasingly in recent years, that the dental surgery is no longer an acceptable place to administer a general anaesthetic. Over the years, demand has fallen steadily and when I gave up this service in mid-January, I had been attending three dental practices on a monthly basis, anaesthetising a total of about 30 patients per month. I recently telephoned the three dentists in question to ®nd out how many patients they had to refer on as untreatable in the last six months. The total is about three per month, or 10% of the number of patients we were treating until six months ago. This is from a total NHS population which yields quite a few patients with serious dental neglect. The implication is therefore that 90% of the patients I had been anaesthetising could have been managed without a general anaesthetic. The remaining 10% could be referred to the local hospital's dental department without swamping the system. I rest my case! H. L. Goldwater Prestwich, Manchester M25 0FR, UK

Abstract: OBJECTIVE Many publications have linked surgical glove powder to inflammatory reactions of the peritoneum, pleura, pericardium and meninges. Accidental contamination may also increase the likelihood of complications after spinal and epidural anesthesia. We aimed to analyze the morphological characteristics of microscopic particles adhering to surgical gloves and to analyze how likely such particles are to enter the epidural space during catheterization. MATERIAL AND METHOD One hundred epidural catheters were studied in two groups (A and B) of 50. Group A catheters contained stylettes and the distal ends were open (Vygon). Group B catheters contained no stylettes and had closed distal ends and three side openings (Becton Dickinson). Continuous epidural anesthesia was simulated with half the catheters in each group (25) by touching the distal end of each line with the gloves and later inserting the catheter through a Tuohy needle. All catheters--those used in the simulation as well as the untouched ones--were then examined under a scanning electron microscope. The particles on the internal and external surfaces of the gloves had previously been identified under a microscope and analyzed by X-ray diffraction. RESULTS Gloves: external glove surfaces carried particles measuring between 3 and 4 mu; their morphology was consistent with calcium carbonate. On internal surfaces we found larger particles, between 11 and 14 mu in diameter, shaped differently and of smooth appearance. Analysis of the latter showed them to contain traces of magnesium and to have characteristics consistent with organic molecules. The particles of one surface were never observed on the other. Catheters: the non-manipulated catheters in both groups contained no free particles matching those described above, whereas the outside surfaces of the catheters in contact with gloves contained particles consistent with those of external glove surfaces. The number of particles per square millimeter of surface was 2,598 (95% CI 2,200 to 2,900) in group A catheters and 2,340 (95% CI 2,000 to 2,600) in the group B catheters (p = NS). The differences in the number of particles adhering to catheters touched by gloves and those that had not been manipulated were statistically significant (p < 0.001). CONCLUSIONS Particles adhering to gloves can be drawn into the epidural space during continuous epidural anesthesia. All unnecessary manipulation should therefore be avoided, and the portion of the catheter to be inserted into the epidural space should not be touched in order to prevent possible nonspecific meningeal inflammatory responses.

Abstract: In patients scheduled for cesarean section (c-section) using combined spinal epidural anesthesia (CSEA), we compared the cephalad spreading speed during double-segment technique (DST) with that of single-space technique (SST) of CSEA In the patients of SST group (n = 169), a 17-G Tuohy needle was introduced at the L 3-4, and then a long spinal needle was inserted through the Tuohy needle In the patients of DST group (n = 16), a Tuohy needle was introduced at the T 11-12, and a spinal needle was inserted at the L 3-4 After 03% hyperbaric dibucaine 10 ml was injected through the spinal needle, 15% mepivacaine 10 ml was injected through the epidural catheter in both the groups The analgesic level was measured at 5-min intervals, and blood pressure and complaints of patients were also recorded The cephalad spread of analgesia was significantly higher in DST group than in SST group at 5 and 10 min after the administration of local anesthetics Two patients in SST group, epidural catheterization was not possible There were no difference in the incidences of hypotension, nausea and dyspnea between the groups We conclude from these results that DST for CSEA is preferable to SST for c-section