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E-letters: Electronic letters published:
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Re: FAILED SPINAL: EMERGING PRACTICE ISSUES
- Paul D W Fettes, J-R Jansson, and JAW Wildsmith (12 August 2009)
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Re: Intracranial hypotension resulting in dry lumbar puncture
- Paul D W Fettes, J-R Jansson and JAW Wildsmith (7 August 2009)
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FAILED SPINAL: EMERGING PRACTICE ISSUES
- Amitabh Dutta (7 August 2009)
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Re: Ultrasound and spinal anaesthesia
- Paul D W Fettes, J-R Jansson, JAW Wildsmith (27 July 2009)
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Intracranial hypotension resulting in dry lumbar puncture
- Niraj Sinha (21 July 2009)
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Intracranial hypotension resulting in dry lumbar puncture
- Niraj Sinha (21 July 2009)
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Ultrasound and spinal anaesthesia
- Piotr Szawarski, Dr Michał Bryś, Dr R Blanco (16 July 2009)
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Re: Can we blame the temperature?
- Paul D W Fettes, Jan-Robert Jansson, and Tony Wildsmith (9 July 2009)
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Re: Use of Luer connection syringes for spinal anaesthesia
- Paul D W Fettes, Jan-Robert Jansson, and Tony Wildsmith (1 July 2009)
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Can we blame the temperature?
- jithesh appukutty (23 June 2009)
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Use of Luer connection syringes for spinal anaesthesia
- Stuart Davies (23 June 2009)
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Re: Anatomical causes of failed spinal anaesthesia may be commoner than thought...
- Paul DW Fettes, Jan-Robert Jansson, and Tony Wildsmith (17 June 2009)
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Re: Failed Spinal Anaesthesia
- Paul D W Fettes, Jan-Robert Jansson, and Tony Wildsmith (16 June 2009)
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Anatomical causes of failed spinal anaesthesia may be commoner than thought...
- Philip A Popham (9 June 2009)
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Failed Spinal Anaesthesia
- Jamil .S Anwari, Riyadh, Saudi Arabia. (4 June 2009)
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Paul D W Fettes , J-R Jansson, and JAW Wildsmith
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We thank Dr Dutta for both his interest in our review and his comments. We think that most of points are variants of those made in the review, but we would like to make three comments about the third paragraph, entitiled 'Technical practices': First, we are surprised to read that some practitioners may be asking the patient to make a significant change in position while the spinal needle is still in place. This is a practice which we would discourage because of the risk of tissue damage and or needle breakage. Second, fluid extrusion out of the epidural needle when the epidural catheter is inserted is a simple displacement of one object by another when saline has been used to demonstrate a 'loss of resistance'. If it occurs with a 'loss of resistance to air' technique then it is more likely that there has been an inadvertent dural puncture with the Tuohy needle. Third, and more relevant to post dural puncture headache than to failed spinals, the 'tin-lid' phenomenon is a feature of 'cutting ' rather than 'pencil point' needles which are widely used today. Although they are often erroneously termed 'atraumatic', the latter actually cause more trauma to the dura mater producing a ragged hole (as if shot by a bullet) rather than the neat u-shaped hole produced by the cutting needles (1). However, the neat U shaped hole produced by the cutting needle is thought to remain open as a flap (this is the 'tin-lid' phenomenon referred to by Dr Dutta) and this has been used as an explanation for the higher incidence of headache with these needles. 1. Reina MA et al. An in vitro study of dural lesions produced by 25- gauge Quincke and Whitacre needles evaluated by scanning electron microscopy. Reg Anesth Pain Med, 2000;25(4):393-402. Conflict of Interest:None declared |
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Paul D W Fettes , J-R Jansson and JAW Wildsmith
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We thank Dr Sinha for this interesting comment. The problem in these patients was, of course, with diagnostic lumbar pucture, but spinal anaesthesia would obviously be technically difficult. However, we would hope that the neurological features seen in these patients would alert any anaesthetist to potential problems and perhaps lead to the choice of an alternative anaesthetic method. If lumbar puncture must be performed in such patients (perhaps for diagnostic purposes), use of the sitting, rather than the usual lateral, position may aid success because the lumbar CSF pressure will be greater. Conflict of Interest:None declared |
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Amitabh Dutta, Consultant Anaesthesiologist Department of Anaesthesiology, Pain & Perioperative Medicine, Sir Ganga Ram Hospital, Delhi, India
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A successful technical (correct placement of spinal needle exit hole in the subarachnoid space)-functional (utilizing appropriate dose, baricity of local anaesthetic/adjuncts and patient position in consonance with the proposed surgery) continuum is vital to positive outcome of spinal neuraxial anaesthesia. Fettes et al 1, in their review, have elaborated and analyzed possibly every aspect of a failed spinal anaesthetic. However, a few practice-related concerns (given below) remain, which need to be further clarified. Selective spinal anaesthesia (SSA): overzealous pattern of SSA practices (overly lowering local anaesthetic dose, indiscriminate addition of fentanyl/adjuncts, decreased total drug volume, etc.)2-4 and attempts to achieve exact desirable spinal blockade effects often leads to failure/ patchy effect/ inadequate level following a successful spinal tap. Combined spinal epidural (CSE): the advent of CSE and its growing popularity adds to the problem, as perfection-inclined regional anaesthesiologists, in presence of epidural catheter back up, tend to go more the SSA way. However, it takes about twenty minutes to get an effective epidural, and the backup epidural top-up used early following an ineffective spinal, more often than not, is inadequate (volume), weak (decreased local anaesthetic concentration) or too research-oriented (use of 0.9% saline as top up) 5 to effectively compliment the existent spinal effect. Technical practices: spinal anaesthesia failure, especially involving SSA, may be secondary to pure technical reasons. First, achieving the cerebrospinal fluid outflow in a flexed spine patient position (stretched dura mater) and then telling the patient to relax (lax dura mater) while injecting the drug. This may alter longitudinal visco-elastic dural tension and puncture hole shape6, 7 leading to drug leaking into the epidural space with subsequent partial spinal effect. Second, the tendency to withdraw the spinal needle quickly and swiftly following subarachnoid drug injection causes drug leak into the epidural space as evinced by common occurrence of fluid exiting out of epidural needle hub while inserting the epidural catheter during a CSE. The leaked drug volume may be significant enough, especially during SSA, to result in a failed spinal block. In both the above stated scenarios, the 'tin-lid' phenomenon (manifests with all needle sizes) 8 that is capable of sealing the resultant dural hole may not occur. This may result in continuous drug leak causing partial spinal effect initially and post dural puncture headache later. In conclusion, failed spinal anaesthesia warrants a closer look into the technical and functional processes involved in administering an intrathecal block. Clear orientation of the possible causes and consistent remedial manoeuvres would help obviate the ever-present evil of failed spinal anaesthesia. References: 1.Fettes PDW, Jansson JR, Wildsmith JAW. Failed spinal anaesthesia: mechanisms, management, and prevention. Br J Anaesth 2009; 102: 739-48 2.Dutta A, Taneja A. Minimum effective dose of bupivacaine required for transurethral procedures remains uncertain. Anesth Analg 2007; 105: 1170 3.Zohar E, Noga Y, Rislick U, Leibovitch I, Fredman B. Intrathecal anesthesia for elderly patients undergoing short transurethral procedures: a dose-finding study. Anesth Analg 2007; 104:552–43. 4.Kampe S, Pietruck C, Diefenbach C. Density determination of bupivacaine and bupivacaine-opioid mixtures for spinal anesthesia. Anesth Analg 2003; 96:1234 5.Trautman WJ, Liu SS, Kopacz DJ. Comparison of lidocaine and saline for epidural top-up during combined spinal-epidural anesthesia. Anesth Analg 1997; 84: 574-77 6.Patin DJ, Eckstein EC, Harum K, Pallares VS. Anatomic and biomechanical properties of human lumbar dura mater. Anesth Analg 1993; 76:535–40 7.Rosser BH, Schneider M. The unflexed back and a low incidence of severe spinal headache. Anesthesiology 1956; 17: 288-92 8.Dittmann M, Schafer H. -G, Ulrich J, Bond-Taylor W. Anatomical re- evaluation of lumbar dura mater with regard to postspinal headache: Effect of dural puncture. Anaesthesia 2007; 43: 635-37 Conflict of Interest:None declared |
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Paul D W Fettes , J-R Jansson, JAW Wildsmith
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We note the comments from Dr Szawarski and colleagues, but have to point out that they are wrong in stating that we did not mention ultrasound. Our review states, quite specifically, that “Advances in ultrasound technology are reaching the stage where it can be used to overcome difficulties with lumbar puncture, but clinicians will still need to be aware of the problems and how they should be overcome.” Although we agree that the NICE guidance which they refer to may increase use of ultrasound, the advice relates predominantly to peripheral, not central, nerve block. A subsection does refer to the use of ultrasound in epidural catheter insertion, but there is no mention of its use in dural puncture per se. Conflict of Interest:None declared |
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Niraj Sinha
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Dear Editor Intracranial hypotension should be considered in differential diagnosis when an experienced anaesthetist is sure that his spinal needle is in the intrathecal space yet CSF is not visible. There are case reports of dry lumbar puncture in this medical condition (1). Patients with spontaneous intracranial hypotension may or may not complain of symptoms similar to post dural puncture headache. Some of them never get symptoms (2). In the symptomatic group the postural component of headache disappears in chronic cases. These patients are likely to result in dry tap. Reference: 1.Yan-qing F, Cheng Z ET al. Spontaneous intracranial hypotension: report of two cases. Chin Med; 2004; 117; 1884-88 2.Mokri B, Atkinson JLD, Piepgras DG. Absent headache despite CSF volume depletion (intracranial hypotension). Neurology 2000; 55:1722-1724 Conflict of Interest:None declared |
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Niraj Sinha
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Dear Editor Intracranial hypotension should be considered in differential diagnosis when an experienced anaesthetist is sure that his spinal needle is in the intrathecal space yet CSF is not visible. There are case reports of dry lumbar puncture in this medical condition (1) Patients with spontaneous intracranial hypotension may or may not complain of symptoms similar to post dural puncture headache. Some of them never get symptoms (2). In the symptomatic group the postural component of headache disappears in chronic cases. These patients are likely to result in dry tap. Reference: 1.Yan-qing F, Cheng Z ET al. Spontaneous intracranial hypotension: report of two cases. Chin Med; 2004; 117; 1884-88 2.Mokri B, Atkinson JLD, Piepgras DG. Absent headache despite CSF volume depletion (intracranial hypotension). Neurology 2000; 55:1722-1724 Conflict of Interest:None declared |
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Piotr Szawarski, SpR Anaesthetics University Hospital Lewisham, Dr Michał Bryś, Dr R Blanco
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Editor - We have read with interest an article by Fettes and colleagues (1). Authors state, referring to location of subarachnoid space that: "accurate location can be difficult using clinical landmarks". They do not make any mention of a possibility of using ultrasound. Although guided technique is not feasible, ultrasound can enable to identify the level, midline and depth to the subarachnoid space [figure 1_attachment]. As with any technique appropriate training and practice is required for proficiency. Just like video-laryngoscopy and fibreoptic technology continue to revolutionise our management of difficult airway ultrasound should be viewed as a tool for any percutaneous technique. The exposure of trainees and consultants to ultrasound guided techniques varies across hospitals, but with new NICE guidelines for use of ultrasound in regional anaesthesia (2) acceptance of this technology and increased scope of its application is likely. References: 1. Fettes P. D. W. et al Failed spinal anaesthesia: mechanisms, management, and prevention Br. J. Anaesth. 2009 102: 739-748 2. NICE Ultrasound-guided regional nerve block: guidance http://www.nice.org.uk/guidance/IPG285/NiceGuidance/pdf/English Conflict of Interest:None declared |
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Paul D W Fettes , Jan-Robert Jansson, and Tony Wildsmith
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We thank Dr Appukutty for his comments, but they beg a number of questions, such as where he works, which manufacturer's products he has been using and precisely what density of bupivacaine solution he is referring to. However, some comments may be relevant: 1. Amide local anaesthetics, even in solutions which also contain glucose, are remarkably stable and unlikely to lose their potency, even after several years of storage. 2. Local anaesthetics should be stored in the range of temperatures recommended by the manufacturer. In the UK 'room temperature' is within that range. However, Astra-Zeneca state that glass ampoules of bupivacaine for spinal use are sterilised by autoclaving twice. A first sterilisation is performed after filling to ensure the sterility in the solution during handling and storage. A second sterilisation is performed after blister packing. The influence of accelerated conditions on the bupivacaine chemical stability, e.g. heat-treatment at 120 °C for hours, shows that the product is extremely stable (unpublished data). 3. When glucose free solutions of bupivacaine are under consideration the change in baricity associated with warming to body temperature does, on occasion, result in a very unexpected pattern of block.1,2 4. As to his conclusion that the bupivacaine solution was the "primary suspect" we can only refer him back to our final paragraph! Refs: 1. Hocking G, Wildsmith JAW. Intrathecal drug spread. Brit J Anaesth 2004; 93: 568-78 2. Lee JA, Atkinson RS. Sir Robert Macintosh’s Lumbar Puncture and Spinal Analgesia. Edinburgh; Churchill Livingstone: 1978. Conflict of Interest:None declared |
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Paul D W Fettes , Jan-Robert Jansson, and Tony Wildsmith
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We thank Dr Davies for his comment. To be pedantic for a moment, all currently available spinal spinal needles have Luer pattern connectors, and what he is recommending is the use of syringes and needles with Luer-lock connectors. We can appreciate that their use might reduce the risk of anterior or posterior displacement, but we note that he still invokes the qualification "hopefully" so the user must still be aware of the risk. Conflict of Interest:None declared |
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jithesh appukutty
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I read with interest the review article by Fettes PDW. It is a clinical fact that failed spinals are a total rarity and an inadequate block (and an unhappy patient) occurs more frequently. Recently I had few bad experiences with completely inadequate block height and a totally failed spinal. After having thought about it, I reached a conclusion that the primary suspect was the Hyperbaric bupivacaine. I switched the manufacturer and my spinals were back to being how they used to be. The company responded by saying "The Bupivacaine heavy has not been stored at appropriate temperature". How lower than room temperature should we store the vials/ampoules? In my relatively short practice in close to 3000 spinal anesthesia, I had not come accross such a significant effect. Do I take that, even a minor differences in baricity ofbupivacaine 0.5%, for example, being slightly hyperbaric at 24°C (density 1.0032 kg m–3), but slightly hypobaric at 37°C (density 0.9984 kg m–3)(1) can cause completely opposite distribution patterns,(2) and may also account for the large variability in the spread of plain bupivacaine when injected at ‘room’ (which may vary considerably) temperature.(3) 1. Nicol ME, Holdcroft A. Density of intrathecal agents. Br J Anaesth 1992; 68: 60–32. 2. Callesen T, Jarnvig I, Thage B, Krantz T,Christiansen C. Influence of temperature of bupivacaine on spread of spinal analgesia. Anaesthesia 1991; 46: 17–19 3. Stienstra R, van Poorten JF. The temperature of bupivacaine 0.5% affects the sensory level of spinal anesthesia. Anesth Analg 1988; 67: 272–6 Conflict of Interest:None declared |
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Stuart Davies, Consultant Anaesthetist Singleton Hospital, Swansea
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In the Review article "Failed spinal anaesthesia: mechanisms, management and prevention" by Fettes, Jansson and Wildsmith, the authors discuss the potential for anterior or posterior displacement of the needle when the syringe is attached to the needle as a potential mechanism for failure of spinal anaesthesia. This is certainly the case when a bayonnet connection syringe is used, as the attachment of syringe and needle requires application of an anterior force to the former and a posterior force to the latter, which hopefully does not lead to any movement in either direction of the needle. If a Luer connection syringe is used, the hub of the needle can be held with one hand (usually the left) applying an anti-rotational force, whilst the syringe is gently engaged into the hub of the needle by means of a clockwise rotational force by the other hand. It is important that care is taken to fully engage the syringe to prevent the risk of leakage as mentioned by the authors as a risk with this combination. However, having used a Luer connection syringe for 15 years in my practice, I am convinced that this makes displacement of the needle less likely to occur during connection. Conflict of Interest:None declared |
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Paul DW Fettes , Jan-Robert Jansson, and Tony Wildsmith
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We thank Dr Popham for his interest in, and support for, our review. In experienced hands the incidence of failed spinal anaesthesia (<<1%) is well below the incidence of the cysts which he refers to. If they were causing clinical problems we do not think that failure would be so rare, even in experienced hands. His comments do add some weight to the view (which we decided, perhaps wrongly, not to express in the paper) that a magnetic resonance imaging scan should be considered in any patient in whom spinal anaesthesia has failed. Such investigation might show that anatomical 'abnormalities' are more common causes of failure than was thought previously, but we cannot agree with his conclusion that these might be the primary cause of problems. The main purpose of our review was to widen the recognition that spinal anaesthesia can fail through a large number of mechanisms and nothing must detract from that assessment. Conflict of Interest:None declared |
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Paul D W Fettes , Jan-Robert Jansson, and Tony Wildsmith
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We thank Dr Anwari for his kind comments on our review of failure during intended spinal anaesthesia, and would agree that the suitability of the method should be assessed on an individual patient basis. In regard to the problems which he mentions they are often more related to the maintenance of full consciousness than any other feature of spinal anaesthesia. As he notes, many techniques are available for dealing with the consequences, but careful, systemic administration of adjuvant sedative or analgesic drugs has much to offer, even in the obstetric setting. Conflict of Interest:None declared |
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Philip A Popham The Royal Women's Hospital, Melbourne, Australia
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I read with interest the review of potential causes of failed spinal anaesthesia by Fettes and colleagues (1). I am concerned that they appear to dismiss extradural cysts too readily. A variety of types have been described. The commonest are thought to be Tarlov cysts which, with the increasing use of magnetic resonance imaging, are now estimated to be present in 4.5–9% of the adult population (2,3). Penetration of such a cyst during attempted spinal anaesthesia would be likely to produce an initial apparently normal "flow" of CSF, but injection of local anaesthetic would produce little or no true intrathecal spread of anaesthetic (depending on the size of the neck of the cyst) and hence inadequate or absent spinal anaesthesia. A repeat attempt at the same interspace may well re-puncture the cyst with the same effect, while the use of a combined spinal epidrual technique may produce no spinal anaesthetic component but an adequate epidural spread since the cyst was not involved. Whilst I would certainly agree with all the other potential causes of a failed spinal mentioned by the authors, it may well be that inadvertent puncture of a Tarlov cyst is much commoner than previously thought and may well account for all the signs and most of the occurrences of failed spinal anaesthesia. 1. P. D. W. Fettes, J.-R. Jansson, and J. A. W. Wildsmith Failed spinal anaesthesia: mechanisms, management, and prevention Br. J. Anaesth. 2009; 102: 739-74 2. Acosta L, Quinones-Hinojosa A, Schmidt M H, Weinstein P R. Diagnosis and management of sacral Tarlov cysts. Case report and review of the literature. Neurosurg Focus 2003; 15: E15. 3. J. Hoppe, P. Popham. Complete failure of spinal anaesthesia in obstetrics. Int J Obstet Anesth (2007) 16, 250–255 Conflict of Interest:None declared |
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Jamil .S Anwari, Consultant Anaesthetist Riyadh Military Hospital, Riyadh, Saudi Arabia.
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Dr Fettes and his colleagues are to be commended on elaborating the mechanism and management of failed spinal anaesthesia in a sequential and logical fashion 1. Broadly speaking, the causes of failed spinal anaesthesia can be categorized under two headings; technical and non- technical. The former includes all causes in which there are pharmacological failures to target a certain length of the spinal cord. Certainly most failed spinal anaesthesia falls in this category. In the latter, despite an apparently successful spinal block, the patient feels unpleasant. I would like to express a few comments on this aspect. Pre-operative screening of patients is important to identify where failure of spinal anaesthesia (for non- technical reasons) is likely occur. This mainly applies to psychologically immature or disturbed patients and psychiatric patients. In extreme such cases, regional should not be offered. It is agreed that during pre-operative canvassing for spinal anaesthesia, the patient should receive facts explained in lay terms. False promises such as “You are not going to feel anything” should not been made. However, the patient may still feel unpleasant sensations during the surgical manipulation of viscera (i.e. exteriorization of uterus) despite an apparently adequate level and quality of (spinal) block 2. In such instances, not only should surgical manoeuvres be gentle but the surgeon should also inform the anaesthetist in advance if traction or exteriorization of viscera is required. Stating the obvious, the operating theatre environment should always be caring and friendly. In some patients, the irremovable thought of their body being cut with a knife makes them uncomfortable. Therefore, even when nociceptive impulses are blocked at the spinal level, pain can still be “created” at a higher level. Distraction therapy such as friendly conversation, the presence of a close friend or relative and allowing the mother to cuddle her new born is often employed. Recently, audio-visual distraction has been used in peri-operative pain management 3. Is there then any room for spirituality in the operating theatre? It may be an ethical dilemma when a patient is reluctant to have spinal but it is considered safe for him/her. Are we justified then in pressurising the patient to accept this? As pain is a subjective phenomenon, it is the patient who finally judges the adequacy of spinal anaesthesia. What if the patient decides to sue the anaesthetist after the operation? The validity of informed consent in such situation is questionable. Wisdom and tacit knowledge guide us to solve such problems 4. REFERENCE 1. Fettes PDW, Jansson JR, Wildsmith JAW. Failed spinal anaesthesia: mechanisms, management, and prevention. Br J Anaesth 2009; 102:739-48. 2. Hirabayashi Y, Saitoh K, Fukuda H, Shimizu R. Visceral pain during caesarean section: effect of varying dose o spinal amethocaine. Br J Anaesth 1995; 75:266-68. 3. Schecter WP, Farmer D, Horn JK, Pietrocola DM, Wallace A. Special consideration in Perioperative pain management. Audiovisual distraction in geriatrics, paediatrics and pregnancy. Journal of the American College of surgeons 2005; 201(4):612-18. 4. Larson J. Studying tacit knowledge in Anesthesiology: A role for qualitative research. 2009; 110:443-4. Conflict of Interest:None declared |
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