Difficult subarachnoid anaesthesia Prediction and Performance

Vol 2 | Issue 2 | July-December 2021 | Page 92-99 | André Van Zundert

DOI: 10.13107/ijra.2021.v02i02.034

Authors: André Van Zundert [1, 2]

[1] Department of Anaesthesia, The University of Queensland, Faculty of Medicine, Brisbane, Queensland, Australia.
[2] Department of Anaesthesia and Perioperative Medicine, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia.

Address of Correspondence
Professor Dr. André Van Zundert,
Professor & Chair Anaesthesiology, The University of Queensland, Faculty of Medicine,
Brisbane, Queensland. Department of Anaesthesia and Perioperative Medicine, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia.


Spinal anaesthesia (SA) has enjoyed a long history of success, celebrating soon its 125th anniversary. Puncturing the dura mater is considered a simple procedure, followed by a subarachnoid injection of a local anaesthetic (LA) agent into the cerebrospinal fluid (CSF). Even when the technique is performed perfectly, there is no guarantee that the block sits perfectly. Failure is not uncommon and encompasses a range from total absence of any neuraxial blockade, a partial block (insufficient height, quality or duration) or a patchy block. Table 1 lists a large number of potential causative factors that may result in a failed spinal anaesthetic, providing suggestions of solutions. Analysing each distinct phase of the procedure, i.e., spinal puncture, injection of local anaesthetic solution, spread of the local anaesthetic solution through the cerebrospinal fluid, action of the drug on subarachnoid neural tissue and patient management, are the keys to success at each stage. Mechanisms of failure of spinal anaesthesia include insufficient preparation and check of equipment and drugs, suboptimal positioning of the patient, unsuccessful puncture due to inadequate training or experience and inadequate use of needles and local anaesthetic solution.1-5 Besides operator, preparation, technique-dependent and patient-related factors (anatomical variations), there are also organisational factors (lack of block room, lack of adequate monitoring and trained personnel, insufficient time between block and onset of surgery, subsequent management following block). The use of the correct local anaesthetic (dose, volume, concentration) injected at the correct lumbar interspace is of paramount importance to produce an adequate spinal block for the right surgical intervention.
Nevertheless, failures may still occur. Therefore, the anaesthetist should always have a contingency plan for a failed spinal block. Indeed, patients expect reliable surgical anaesthesia when undergoing an operation under regional anaesthesia. If the block fails, we need to be ready to offer a solution, using rescue techniques. The alternatives are either to repeat the spinal anaesthesia or to convert to a general anaesthetic.
Failed spinal anaesthesia has roughly three reasons: a) the local anaesthetic solution does not reach the subarachnoid space; b) the drug has been injected at the right location, but the block is not what is expected; and c) the local anaesthetic solution works well, but the dosage chosen is not correct or results in unilateral or patchy blocks as the resulting block is deficient in quantity, quality or duration.


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How to Cite this Article: Van Zundert A | Difficult Subarachnoid Anaesthesia Prediction and Performance | International Journal of Regional Anaesthesia | July-December 2021; 2(2): 92-99.

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