A Regional Review

Journal Reviewed: Canadian Journal of Anaesthesia Issues: July, August, September 1999 Reviewer: Dr C Quan MB BCh (Registrar, University of the Witwatersrand) Summary There has been a plethora of interesting articles on regional anaesthesia in recent issues of the CJA. We look at: The Epidural blood patch Obstetric regionals Transient radicular irritation Intra-articular analgesia. You may also wish to briefly browse our editorial comment 1. The Epidural Blood Patch (EBP) In anexcellent review, Duffy and Crosby look at: Indications for and contraindications to EBP; Technical details; Whether it works for headache and other complications; How EBP works; Long-term consequences of EBP; Alternatives to using blood; and EBP (or saline) for prophylaxis; In brief, EBP is indicated as the only really effective management of moderate to severe post-dural puncture headache (PDPH), with no substantial evidence that delay for say 24 hours is of value. Apart from problems with consent, local anatomy, and coagulation abnormalities, it seems prudent to avoid EBP in the presence of fever or sepsis, but HIV positive patients should not be denied its advantages. The volume of blood administered is controversial and little good research exists to tell us whether to use, say, 10 or 20ml. Note that 20ml of epidural fluid may transiently raise CSF pressure to 85 cmH 2 O ! Two hours of recumbency following EBP is advisable. EBP fails to provide symptomatic relief in one quarter to one third of PDPH. It appears inefficacious for the cranial nerve palsies, seizures and intracranial haemorrhage that infrequently follow dural puncture, but is beneficial for associated hearing loss. Mechanisms of action are unclear, possibly being related to a combination of transmitted pressure effects (a "pressure patch") and "plugging" of the hole. The effects of blood appear to be sustained for longer than those of other fluids. Epidural crystalloid appears less effective than EBP; an isolated but impressive report attests to the value of epidural Dextran 40, although safety considerations need to be resolved. Previous dural puncture (with or without EBP) seems to be a marker for subsequent problems. Studies looking at prophylaxis following dural puncture are of variable quality but suggest that both epidural saline administration and EBP are of value, especially with large-bore puncture. Article 1: The epidural blood patch. Resolving the controversies Journal: Canadian Journal of Anaesthesia 1999 46 (9) 878-886 Article type: Review Authors: Duffy PJ & Crosby ET 2. Obstetric regionals Three CJA articles are pertinent.The first, motivated by a recovery room arrest following spinal anaesthesia, looks at transport of patients following Caesarean section under spinal. Nearly 200 ASA 1 or 2 patients were divided into two groups - the first transported with 30 o upper body tilt, the second group supine. In nearly one fifth of patients the block ascended two to seven dermatomes from the T4 or higher level usually recorded at the start of surgery! Substantial hypotension occurred in 10%, independent of positioning. A cautionary study. The second article considers the use of epidural tramadol, suggesting this management as an adequate means of providing post-operative analgesia without respiratory depression. Analgesic requirements with 100mg were similar to those with 200mg and superior to those in controls. Another study looked at varying doses (0.1mg vs 0.25mg) of intrathecal morphine for analgesia following Caesarean section. The lower dose was found to be as effective in relieving pain, with less pruritus and nausea, as assessed by visual analogue scales. Respiratory depression was not apparently looked for as this was considered to be "unlikely with the doses currently used". Article 2: Spinal block levels and cardiovascular changes during post-Cesarean transport Journal: Canadian Journal of Anaesthesia 1999 46 (8) 736-740 Article type: Observational clinical study Authors: Bandi E, Weeks S, Carli F Article 3: Epidural tramadol for postoperative pain after Cesarean section Journal: Canadian Journal of Anaesthesia 1999 46 (8) 731-5 Article type: Prospective randomised clinical trial Authors: Siddik-Sayyid S, Aouad-Maroun M, Sleiman D, Sfeir M, Baraka A Article 4: Comparison of 0.25 mg and 0.1 mg intrathecal morphine for analgesia after Cesarean section Journal: Canadian Journal of Anaesthesia 1999 46 (9) 856-860 Article type: Prospective randomised clinical trial Authors: Yang T, Breen TW, Archer D, Fick G 3. Transient radicular irritation (TRI) An article from the September CJA despite its title only transiently addresses TRI. The main conclusion of the study is that spinal procaine is effective in surgery of brief duration, but the 25% prolongation of action seen with added adrenaline (epinephrine) is offset by frequent nausea.Although only one patient had symptoms of TRI on telephonic enquiry after 48 hours, the confidence intervals are wide (1 to 9%) owing to the study size (62 patients). Contrast this study with a landmark study from the 1995 BJA, where use of 5% hyperbaric lignocaine was associated with a 10% incidence of TRI, not seen with bupivacaine. Article 5: Spinal procaine with and without epinephrine and its relation to transient radicular irritation Journal: Canadian Journal of Anaesthesia 1999 46 (9) 846-849 Article type: Prospective randomised double-blind clinical trial Authors: Bergeron L, Girard M, Drolet P, Grenier Y, Le Truong HH, Boucher C 4. Intra-articular Analgesia A study byVarkel et al compares the use of intra-articular fentanyl with that of morphine following arthroscopic knee surgery performed on sixty nine healthy individuals. Patients were randomised into three groups: 20ml saline + 50mg fentanyl 20ml saline + 3mg morphine 20ml saline alone (placebo). Pain scores were consistently worse in the placebo group, with similar initial scores in the other two groups, after one hour favouring the patients who received fentanyl. The authors conclude that fentanyl is the better agent (for the given doses). Another study of ninety ASA 1 or 2 patients compared intra-articular tenoxicam against the same drug administered intravenously. Superior analgesia was achieved using the intra-articular route. Article 6: Intra-articular fentanyl compared with morphine for pain relief following arthroscopic knee surgery Journal: Canadian Journal of Anaesthesia 1999 46 (9) 867-871 Article type: Prospective randomised clinical trial Authors: Varkel V, Volpin G, Ben-David B, Said R, Grimberg B, Simon K, Soudry M Article 7: Intra-articular tenoxicam improves post-operative analgesia in knee arthroscopy Journal: Canadian Journal of Anaesthesia 1999 46 (7) 653-657 Article type: Prospective randomised double blind clinical trial Authors: Colbert ST, Curran E, O'Hanlon DM, Moran R, McCarroll M References Tarkkila P, Huhtala J, Tuominen M Transient radicular irritation after spinal anaesthesia with hyperbaric 5% lignocaine British Journal of Anaesthesia 1995 74(3) 328-9 Editorial pointers Why do some subjects get complications of dural puncture, and others not? We commend to your attention the following neglected article: Kempen PM & Mocek CK Regional Anesthesia 1997 22(3) 267-272 In this elegant study, the authors looked at how needle bevel orientation influences puncture of a cylindrical membrane. They substantiate the contention that paramedian puncture and lateral bevel orientation cause smaller holes and less CSF leak. Anaesthetists interested in complications of spinal anaesthesia, particularly transient radicular irritation might wish to consult the following brief but well-referenced review: Gielen M Anaesthesia 1998 53 S2 23-5 The author notes the occurrence of transient hearing loss without post-dural puncture headache in several studies, even where fine-bore spinal needles were used. Gielen also stresses that the type of needle may influence CSF leakage - in his study 22G Quincke needles were associated with hearing impairment in 6/18 cases versus 0/17 for Whitacre needles. TRI is also well reviewed, with emphasis on directing the side-opening of pencil-point spinal needles cranially and not injecting hyperbaric solution too slowly. In general, to prevent TRI in spinal anaesthesia, Gielen suggests that lignocaine (lidocaine) should be replaced by "0.5% bupivacaine, hyperbaric or plain, in a low dose of 10mg for short duration; or prilocaine 2% in a dose of 1mg.kg -1 ". Thearticle by Bandi et al is sobering. Apart from the 17.5% of patients who had a two or more dermatome rise in their level of block following surgery, it is remarkable to note the very high levels of sensory blockade found in these pregnant patients given 12-15mg bupivacaine and morphine 0.25mg. Looking at levels of block: Level of block Before surgery After surgery above T1 (Cardioaccelerator fibres are T1 - T4) 35% 48.8% above C5 (Phrenic nerve is C3-5) 1.5% 4% In addition, high sympathetic block and predominant vagal tone necessitated a high incidence of pharmacological intervention - fully 18% were given ephedrine after transfer to the trolley (and this excluded patients given ephedrine just prior to transfer, although the reasons for this exclusion are not made clear)! Several questions need to be raised: Are we over-doing the dose of spinal bupivicaine? (Note however that in this study, the average duration of surgery was a remarkable 74 minutes). Considering the dramatic step-down of monitoring from intra-operative monitoring by a dedicated anaesthetist to post-operative care, is spinal anaesthesia really safer than general anaesthesia? This question is especially relevant in third-world circumstances. Those interested in contemporary use of epidural and spinal opioids can do no better than read the peer-reviewed ASA publication: Bernards CM ASA Refresher Courses in Anesthesiology Vol 27(2)13-30 The author comprehensively reviews spinal opioid bioavailability, distribution, disposal, and the rationale for clinical use. Important points are the benefit of morphine, and the lack of clinical superiority of epidural administration of fentanyl over intravenous administration. Regarding intra-articular opiates and their value, Kalso and colleagues have recently reviewed the rather poor studies that have addressed this therapy: Kalso E, Tramèr MR, Carroll D, et al. Pain 1997 71 127-34 Apart from its therapeutic potential, the intra-articular efficacy of opiates is important to those championing the role of opiates in peripheral inflammation. The review of Kalso is fairly rigorous, and should be recommended reading for anyone designing a study of intra-articular analgesics. The authors conclude that the evidence suggests benefit from intra-articular morphine, but is not compelling, and that there is no evidence for a dose-response effect. Intra-articular morphine administration is not entirely benign, as shown by a recent letter in Anaesthesia and Intensive Care, where 10mg caused profound, delayed respiratory depression: Francis PH Anaesth Intensive Care 1999 27 669-670 Ed       Up Date of First Publication : 2001-5-9 Date of Last Update : 2006/10/23 Web page author: Click here