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Copyright ©The Author(s) 2024.
World J Crit Care Med. Sep 9, 2024; 13(3): 94157
Published online Sep 9, 2024. doi: 10.5492/wjccm.v13.i3.94157
Table 1 Causes and factors contributing to thoracic epidural failure
Causes of epidural failure
Factors contributing to failure
Incorrect catheter placementMisplacement into paravertebral space, pleural space, or intravascularly
Catheters placed at the wrong level
Equipment failureDebris in the catheter
Disconnections, air locks, or knotting and kinking of the catheter
Epidural space characteristics and complexitiesMidline fat pedicles and adhesions impeding adequate spread of local anesthetics
Table 2 Studies discussing thoracic epidural failure
Ref.
Factors contributing to epidural failure
Porteous et al[5]Equipment failure, such as debris in the catheter, incorrect catheter placement, epidural space characteristics and complexities
Motamed et al[8]Anatomical variances, coiling and kinking of the catheter
Hamilton et al[9]Changes in the position of epidural catheters associated with patient movement
Tran et al[11]Primary failure of thoracic epidural analgesia in training centers
Yeager et al[14]Malposition of epidural catheters
Tsui et al[15]Incorrect catheter placement
Balki et al[16]Incorrect catheter placement
Ghia et al[17]Incorrect catheter placement
Lennox et al[18]Incorrect catheter placement
Sánchez et al[20]Incorrect catheter placement
Johnson et al[21]Incorrect catheter placement
Table 3 Techniques for confirming thoracic epidural catheter position
Technique
Description
Advantages
Disadvantages
Electrophysiological stimulationConnecting nerve stimulator to catheterHigh sensitivity and effectiveness in confirming positionRequires specialized adaptor
Applying current and assessing motor responseCorrelation with adequate postoperative analgesiaDiscomfort to awake patient
Bilateral stimulation indicates proximity to nerve rootDoes not give information on local spread
Limb or truncal response indicates epidural space
Epidural catheter waveformConnecting catheter to pressure transducerSimple technique using readily available equipmentDoes not provide information about catheter level or injectate spread
Confirming epidural space when pulsatile waveform is obtained
Contrast epidurographyTaking X-ray after injection of radio-opaque contrastConfirms epidural position and assesses catheter level and spread patternInvolves X-ray, may not be suitable for all patients
Assessing contrast spread and catheter placementIdentifies anatomical variances and coiling/kinkingTime-consuming. Required training for epiduralgram interpretation
Evaluating bilateral spread and vertebral levelsRisk of transiently raising spinal cord pressure with large volumes
Table 4 Studies done on confirming thoracic epidural catheter position
Ref.
Techniques for confirming catheter position
Teoh et al[10]Surface anatomy as a guide to vertebral level for thoracic epidural placement
Yokoyama et al[13]Evaluation of contrast medium distribution and blockade extent during epidural anesthesia
Yeager et al[14]Fluoroscopy-assisted epidural catheter placement
Tsui et al[15]Confirmation of catheter placement using nerve stimulation
Balki et al[16]Epidural electrical stimulation test
Ghia et al[17]Confirmation of catheter position using epidural pressure waveform and computed tomography catheter gram
Lennox et al[18]Use of pulsatile pressure waveform as a marker for confirming the location of the thoracic epidural space
Sánchez et al[20]Radiological visualization of catheters placed in the epidural space