|Year : 2022 | Volume
| Issue : 4 | Page : 224-226
Successful subarachnoid block following a dry tap in a geriatric patient
Chanise Monteiro Pereira Carvalho, Ashwell Savio Correia, Rohini V Bhat Pai
Department of Anaesthesiology, Goa Medical College, Bambolim, Goa, India
|Date of Submission||20-May-2022|
|Date of Acceptance||11-Jun-2022|
|Date of Web Publication||22-Dec-2022|
Rohini V Bhat Pai
Department of Anaesthesiology, Goa Medical College, Bambolim
Source of Support: None, Conflict of Interest: None
Rationale: Dry tap' is the absence of cerebrospinal fluid (CSF) despite lumbar puncture needle placement in the thecal sac. Patient Concern: it is a troublesome condition and poses significant challenges. Diagnosis: An experienced anaesthesiologist develops the ability to recognise the needle advancing through the ligaments culminating in a subtle 'pop' or 'give way' to ultimately reach the subarachnoid space, and the needle position is confirmed by a free flow of clear CSF. Intervention: subarachnoid block. Outcomes: successful subarachnoid block following a dry tap in a geriatric patient. Lessons: Spinal anaesthesia can be successful despite a dry tap in experienced hands and may be attempted before resorting to alternative techniques.
Keywords: Dry tap, geriatrics, subarachnoid block
|How to cite this article:|
Pereira Carvalho CM, Correia AS, Bhat Pai RV. Successful subarachnoid block following a dry tap in a geriatric patient. Hamdan Med J 2022;15:224-6
| Introduction|| |
Subarachnoid block or spinal anaesthesia is a form of neuraxial anaesthesia commonly used for surgical procedures that are infraumbilical or those involving the lower extremities. A well-trained anaesthesiologist develops the ability to recognise the needle advancing through the high-resistance ligaments culminating in a subtle 'pop' or 'give way' to ultimately reach the subarachnoid space and a confirmatory free flow of clear cerebrospinal fluid (CSF) at the hub of the needle on withdrawal of the stylet. The absence of CSF after a well-placed spinal needle is known as a 'dry tap', a troublesome condition that poses a significant challenge to the anaesthesiologist. We present the case of a successful subarachnoid block following a dry tap in a geriatric patient.
| Case Report|| |
A 76-year-old male with a known history of diabetes mellitus managed on oral hypoglycaemic agents, and bronchial asthmatic currently on a meter-dose inhaler was admitted to the surgical ward with a diabetic foot ulcer for desloughing. The patient, on presentation to the surgical operation theatre was conscious, afebrile with a pulse rate of 80 beats/min, regular and blood pressure of 110/70 mmHg in the recumbent position. Respiratory system examination revealed the presence of bilateral basal coarse crept. The cardiovascular examination was unremarkable. The patient was posted for desloughing of the ulcer on the left foot which was about 7 cm × 6 cm and extended over the ankle of the left lateral malleolus of the fibula. Neuraxial anaesthesia was planned and the patient was positioned in the left lateral decubitus position. Spinal anaesthesia was attempted through the median and paramedian approach in the L3/L4 interspace using a 25-gauge Quincke needle only to fail in both attempts. The needle had been flushed before the second attempt to ensure patency of the lumen. Two more attempts were made in the L4/L5 interspace with the same results. After persuasion, the patient was positioned in the sitting position with feet supported and chest to knees, and the identification of the spine and the intervertebral spaces improved. Spinal anaesthesia was attempted through the midline approach with a 23-gauge Quincke needle in the L3/L4 interspace and the characteristic give way felt only to result in the dry tap. The needle was rotated a 90° with the probability that the needle orifice may not be completely in the subarachnoid space, but further attempts at slight withdrawal or insertion produced no back flow of clear CSF. When the third attempt in the L2-L3 intervertebral space with a 23-gauge Quincke needle through midline approach produced the characteristic give way to feel but no CSF flow, 1.4 ml of 0.5% (H) bupivacaine was injected. After 6 min, a sensory block up to T12 was achieved and the procedure was carried out uneventfully.
| Discussion|| |
Needle puncture of the dura mater, followed by subarachnoid injection of a local anaesthetic is necessary to produce spinal anaesthesia.
Sometimes, CSF is not seen flowing on withdrawal of the stylet resulting in a dry tap despite the characteristic give-way feel. A blocked lumen of the needle is a less likely possibility but nevertheless, the needle and stylet 'fit' should be confirmed before use and the needle should be introduced and advanced only with the stylet in place because the fine-bore needles can easily be blocked with tissue or blood clot.
The other causes of 'dry tap' could be due to the obliteration of the subarachnoid space as the arachnoid collapses on the pia. The physiological cause could include low CSF pressure due to dehydration. Assuming that the patient was dehydrated, adequate fluids were preloaded.
Another cause of dry tap could be severe spinal stenosis which includes narrowing of the thecal sac due to epidural lipomatosis.
When the lumbar interspinous distance was measured using ultrasound and comparisons were made between lateral recumbent with knees to chest, sitting and bent forward over an adjustable bedside stand or sitting position with feet supported and chest to knees, it was found that the last position maximises the interspinous distance. We coaxed the patient to a sitting position and supported his feet and gave him knees to chest position but no avail.
Das et al. have reported a successful subarachnoid block for a caesarean section following a dry tap. Successful subarachnoid block has been achieved in one case following injection of local anaesthetic despite a dry tap following a distinct 'give' by Ramachandran and Ponnusamy.
Fluoroscopic or computed tomography scan guidance to confirm the tip of the spinal needle in case of dry lumbar puncture done for diagnostic or therapeutic purposes has been recommended. A study by Somani et al. showed that the incidence of dry tap during real-time ultrasound spinal injection was 9.7% using the paramedian sagittal oblique ultrasound window. Successful spinal anaesthesia was achieved in all these patients. Angadi et al. have reported the use of pre-procedure ultrasonography of the vertebral assessment which subsequently helped them to perform the subarachnoid block successfully despite dry tap. Pre-procedural ultrasound was shown to reduce the number of spinal attempts with fewer side effects as compared to conventional landmark techniques in parturients.
Inadequate spinal anaesthesia or complete failure of the block is a potential problem which can occur as there is no CSF flow to determine the correct placement of the needle during the injection of local anaesthetic.
Spinal subdural haematoma and subdural anaesthesia leading to high spinal block have been reported in a parturient following injection of bupivacaine despite repeated attempts to locate subarachnoid space resulting in a dry tap. The epidural abscess has been described as a reason for a dry tap; hence, it would be prudent to avoid injection of local anaesthetic if a dry tap is encountered in patients with risk factors for iliopsoas abscess unless confirmed to be otherwise.
| Conclusion|| |
Spinal anaesthesia can be successful despite a dry tap in experienced hands and may be attempted before resorting to alternative techniques. The success rate can be increased with the use of ultrasound.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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