|Year : 2022 | Volume
| Issue : 1 | Page : 39-41
Subarachnoid block in a parturient with ventriculoperitoneal shunt in situ: A case report and review
Bharti Wadhwa, Gurleen Kaur Oberoi, Mousumi Saha, Kirti N Saxena
Department of Anaesthesia and Intensive Care, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi, India
|Date of Submission||10-Apr-2022|
|Date of Acceptance||02-May-2022|
|Date of Web Publication||20-May-2022|
Dr. Mousumi Saha
Department of Anaesthesia and Intensive Care, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi - 110 002
Source of Support: None, Conflict of Interest: None
While it is now conclusively established that subarachnoid block (SAB) for cesarean section has distinct advantages, its administration in a parturient with a ventriculoperitoneal (VP) shunt in situ has been controversial. Over the years, experience with regional anesthesia techniques for labor and operative delivery in patients with VP shunt is accumulating, and various workers have reported safe outcomes with successful administration. In the absence of clinical evidence pointing to significant risks and complications, neuraxial anesthesia may be a safe and suitable alternative alternative to general anesthesia for Cesarean delivery in parturients with VP shunt, provided due considerations are followed. The indications for SAB in a parturient with VP shunt should be based on obstetrics considerations and neurological status.
Keywords: Anesthetic management, pregnancy, shunt malfunction, subarachnoid block, ventriculoperitoneal shunt
|How to cite this article:|
Wadhwa B, Oberoi GK, Saha M, Saxena KN. Subarachnoid block in a parturient with ventriculoperitoneal shunt in situ: A case report and review. J Ind Coll Anesth 2022;1:39-41
|How to cite this URL:|
Wadhwa B, Oberoi GK, Saha M, Saxena KN. Subarachnoid block in a parturient with ventriculoperitoneal shunt in situ: A case report and review. J Ind Coll Anesth [serial online] 2022 [cited 2022 Nov 30];1:39-41. Available from: https://www.jicajournal.in//text.asp?2022/1/1/39/345594
| Introduction|| |
While it is now conclusively established that subarachnoid block (SAB) for cesarean section (CS) has distinct advantages in a parturient, its administration in the presence of a ventriculoperitoneal (VP) shunt in situ has been controversial. There are concerns regarding the risk of brain stem herniation and the introduction of shunt infection., No standard guidelines for the use of neuraxial anesthesia in a parturient with cerebrospinal fluid (CSF) shunts have been established till date.
| Case Report|| |
Our patient was a 30-year-old, multigravida female weighing 60 Kg with VP shunt posted for emergency CS in view of scar dehiscence. She had undergone VP shunt surgery for intracranial hypertension 3 years back, the etiology of which was not clear from the history, and no previous records were available. Following surgery, the patient was on tablet (tab.) phenytoin 100 μg thrice daily for 1 year. There was no history of seizures or signs and symptoms suggestive of raised intracranial pressure (ICP). History and physical examination was unremarkable, and the lumbar spinous processes could be easily palpated. The shunt reservoir was located behind the right mastoid process, and patency was confirmed by palpation. There were no previous treatment papers or computed tomography (CT) scan records, and the patient had to be taken upon an emergency basis in view of scar dehiscence. Although the detailed neurosurgical evaluation and investigation was not possible due to time-sensitive nature of the surgery, a neurosurgery consult was taken, which documented the shunt to be functional and advised preoperative antibiotic prophylaxis with vancomycin and gentamicin. The patient was preloaded with 500 ml of crystalloid as per the standard institutional protocol. Using standard anesthesia technique, SAB was administered with 2 ml 0.5% bupivacaine (hyperbaric) and 10 μg fentanyl at L3–L4 using a 27G Whitacre needle with an introducer needle in lateral decubitus position. Adequate sensory level was achieved, and the intraoperative period was uneventful. A healthy infant weighing 2.940 Kg was delivered with an APGAR (1 + 2 + 2 + 1 + 2) of 8 at 1 min and 5 min. Antibiotic prophylaxis was continued in the postoperative period. No intraoperative and postpartum complications were observed. The patient was followed up for 1 week in the postoperative period and taught to recognize signs and symptoms of central nervous system (CNS) infection and raised ICP. She was discharged from the hospital with instructions to report to the hospital if any signs and symptoms of CNS infection or raised ICP occur.
| Discussion|| |
On search of literature, VP shunt in the parturient can be found as case reports or case series from time to time. However, the reports seem to be either inconclusive or leaning in favor of general anesthesia. This may be because the safety of neuraxial anesthesia is uncertain in patients with VP shunt, and neuraxial anesthesia is generally contraindicated in patients with increased ICP due to the frequently cited risk of brain herniation.,,
It is an undisputed fact that SAB is the technique of choice for CS. The morbidity is reduced, and postoperative recovery is better with SAB, and very often, the patient may also desire a neuraxial technique for cesarean delivery.
To understand the implications of a SAB in a patient with VP shunt, we have to first understand the pathophysiology of intracranial hypertension. In a communicating hydrocephalus, the pressure is uniformly distributed over the intraspinal and cranial compartment, and any change in pressure would thus be transmitted equally over both the compartments. CSF drainage during lumbar puncture would therefore have no effect on the pressure gradient and may even be performed as a part of therapeutic management.,,
In the presence of an obstructive hydrocephalus or a space-occupying lesion, there is an impaired flow between the intracranial and intraspinal compartments, and a rapid loss of CSF can lead to a fall in pressure of the intraspinal compartment. This will create a pressure gradient between the intraspinal and cranial compartments predisposing to brain stem herniation., Therefore, it is important that the following points be kept in mind when assessing a parturient with a VP shunt: (1) cause of intracranial hypertension, (2) whether communicating or obstructive?, (3) is there an increase in ICP?, (4) will the dural puncture predispose to brain stem herniation, and (5) functional status of the VP shunt.
Effect of pregnancy on a ventriculoperitoneal shunt in situ
While the presence of a VP shunt is not a contraindication for pregnancy, an increased incidence of VP shunt malfunction has been observed in the peripartum period. The raised intra-abdominal pressure in a parturient can cause a reversal of the pressure gradient, leading to disruption of the CSF drainage at the distal end of the shunt. The increased production of CSF and the venous engorgement during pregnancy may result in a lower intracranial compliance, both factors predisposing to a rise in ICP in an otherwise normally functioning shunt. The most common symptoms of shunt malfunction include headache, nausea, and vomiting. The early signs and symptoms of shunt failure may be difficult to distinguish from transient headaches of the final trimester and must be carefully evaluated. The other possible reasons for shunt malfunction include infection of the shunt, obstruction, overdrainage, and mechanical complications. Further, in the event of any intra-abdominal infection following CS, there is a risk of adhesion formation around the distal end of the VP shunt, causing obstruction to drainage of CSF and increase in ICP. Thus, there can be significant shunt-related complications during pregnancy and in the first 6 months postpartum.
Therefore, the patient should be managed in close cooperation with a multidisciplinary team of obstetrician, neurosurgeon, and the anesthesiologist in a setup where there are adequate facilities for the management of raised ICP. Ideally, the interdisciplinary management of a pregnant woman with VP shunts should start at the preconception and continue during the antenatal and postnatal periods.
In the preconception period, a thorough evaluation by the neurosurgeon and imaging studies will help in determining whether the shunt is functioning properly and also to yield a baseline value for future comparison in case any ventricular dilatation occurs during pregnancy. Magnetic resonance imaging seems to be a safe, effective tool for monitoring ventricular dilatation and diagnosing shunt failure in both pregnant and nonpregnant women.
The patient's neurological status and the gestational age of the fetus are the two most important parameters when deciding on a shunt intervention or delivery in the event of a shunt malfunction. For women who are in their second trimester and a full-term birth is expected, shunt revision should be the first treatment option, while, in the late third trimester, vaginal delivery or CS would be an appropriate treatment without any intervention.
There is a reluctance to administer spinal anesthesia, and traditionally, general anesthesia (GA) is considered relatively safer. The concern with spinal anesthesia is the risk of introducing infection in the shunt and the possibility of brain stem herniation. Further, GA may provide a better control of ICP intraoperatively.
However, over the years, experience with regional anesthesia techniques for labor and operative delivery in patients with VP shunt is accumulating, and various workers have reported safe outcomes with successful administration.,, In a patient who is fully compensated with a functioning ventriculoperitoneal shunt, the neuraxial block can be safely administered.
In the absence of an obstructive pathology, loss of CSF with SAB is unlikely to cause brain stem herniation and may even be therapeutic. In cases of obstructive hydrocephalus, a sudden change in the balance of pressures as a result of dural puncture carries the theoretical possibility of a brain stem herniation. However, given that the production rate of CSF is around 0.3 ml/kg/h (approximately 20 ml/h in a 70 kg adult), a 25–27G spinal needle is unlikely to produce a significant loss of CSF or pressure gradient in a short time.
In an interesting and landmark case report by Yilmaz et al., SAB was given for CS in a parturient with a VP shunt in situ and a rapidly deteriorating neurological status on the advice of the neurosurgeon. There was an uneventful intrapartum and postpartum period with an improved neurological status in postoperative period which returned to normal by 4th postoperative day. The reason for this could either be an improvement in shunt function due to relief of intra-abdominal pressure following delivery or a therapeutic loss of CSF during the SAB.
SAB in a parturient with VP shunt not only avoids the risk of pulmonary aspiration and increases in ICP with laryngoscopy and intubation, but also has a better maternal fetal outcome with superior postoperative analgesia and early ambulation. Further, it can provide better neurological assessment in the perioperative period. Certain special considerations must be kept in mind when administering SAB in patients with VP shunt in situ.
Ensure that preoperative neurological examination is within the normal limit and document this for medicolegal purpose. Identify and document any signs and symptoms of raised ICP or CNS infections. Know the indication, site, and patency of the shunting device. In an emergency setting, a shunt reservoir palpation test for VP shunt patency can be easily performed by the anesthesiologist to check the patency and functioning of the VP shunt.
Perform neuraxial anesthesia in lateral decubitus position and use atraumatic spinal needles (Whitacre, Sprotte) sized 25G or thinner to minimize loss of CSF. Fluid coloading and the use of vasopressors to avoid cerebral hemodynamic impairment. Asepsis with full barrier protection and antibiotic prophylaxis to avoid CNS infection.
Maintain adequate hydration. Make the patient aware of the signs and symptoms of neurological impairment with instructions to report immediately.
The small volume of the drug injected and the prevalent use of hyperbaric local anesthetics makes it unlikely to reach the tip of the shunt located in the cerebral ventricle. Thus, the presence of a VP shunt has no effect on block onset, sensory level, and duration of the block.
In the absence of clinical evidence pointing to significant risks and complications, neuraxial anesthesia can be administered in a parturient with VP shunt in situ, keeping in mind the abovementioned precautions. Whenever possible, these patients should be managed in centers with neurosurgical facilities. SAB can be a safe and suitable alternative to general anesthesia for cesarean delivery in parturients with VP shunt, provided due considerations are followed. The indications for SAB should be based not on the presence of VP shunt in situ but rather on the basis of obstetric indications and neurological status.
We acknowledge the residents of the Department of Anaesthesia and Department of Obstetrics and Gynaecology and technical OT staff.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her 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 identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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