What the Anesthesiologist Should Know before the Operative Procedure
Inadvertent dural puncture is a risk of epidural anesthesia and occurs when the needle or catheter punctures the dura and arachnoid maters. The incidence of accidental dural puncture varies on the experience of the provider and is approximately 1.5%. When experts in regional anesthesia were asked regarding the incidence of post dural puncture headache (PDPH), the response was 1% for epidural anesthesia and 1% for spinal anesthesia. It is the most common risk disclosed to patients. Not all patients who have an inadvertent dural puncture develop a headache. In the obstetric population, the incidence of headache is 88% with a 16-gauge epidural needle and 64% with an 18-gauge epidural needle. Headache is among the top three causes for a lawsuit to be filed against an anesthesia provider involved with obstetrics.
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
An inadvertent dural puncture results in the leakage of cerebrospinal fluid (CSF) through the dural tear into the epidural space. This loss of CSF may result in a headache due to the loss of the cushion effect of the CSF. The treatment of a PDPH is an epidural blood patch (EBP), the injection of the patient’s blood into the epidural space. An EBP is not an emergency and is not required to be done urgently unless:
The patient develops blurred or double vision. An EBP prevents prolonged injury to the cranial nerves (cranial nerve VI is the one most frequently affected)
Altered mental status occurs from intracranial hypotension
The delay of an EBP 24 hours after the onset of PDPH improves the success rate of the EBP.
2. Preoperative evaluation
Inadvertent dural puncture is a risk for any patient receiving epidural anesthesia/analgesia. Of those patients who have a dural puncture, not all patients will develop a headache. A headache is also a risk of spinal anesthesia. Factors that affect the probability of developing a headache are:
Size of the needle (a larger gauge needle has a lower incidence)
Type of needle (for spinal anesthesia, pencil point design has a lower incidence than Quincke)
Age of patient (older patients have a lower incidence)
Gender (men have a lower incidence)
Type of delivery (those who deliver via cesarean section have a lower incidence)
If the decision to perform an EBP is affirmative, the most important preoperative evaluation is the checking of the patient’s temperature. One would not want to place an EBP in a septic patient as blood is an excellent culture medium; if the patient were septic, the patient would be at risk for the development of an epidural abscess. Some practitioners have recommended the checking of a white blood cell count prior to EBP. One of the physiologic changes of pregnancy is an increase in the white blood cell count, making it elevated in patients without infection. In the general population, a temperature prior to performing the procedure is more cost effective.
3. What are the implications of co-existing disease on perioperative care?
b. Cardiovascular system
Scoliosis is defined as a lateral curvature of the spine. While epidural anesthesia is possible in a patient with scoliosis, the placement of an epidural catheter is technically more difficult and there is a higher incidence of poorly functioning epidural catheters. Also, the incidence of unintended dural puncture is higher, with a reported incidence of 4%. Given the difficulty of placement and the concern with infection, the placement of an EBP in an individual with corrected scoliosis must be decided upon a case-by-case basis.
Achondroplasia is the most common type of dwarfism, with an incidence of 0.5 per 10,000 births. There is a narrowing of the epidural space, which may increase the risk of inadvertent dural puncture.
Increased intracranial pressure
Patients with increased intracranial pressure exhibit headache, vomiting, altered levels of consciousness, and papilledema. Neuraxial anesthesia is typically not done in these patients because of the concern of accidental dural puncture. If accidental dural puncture were to occur in a patient with increased intracranial pressure, the person is at risk for the development of brain herniation.
Pseudotumor cerebri is also known as idiopathic intracranial hypertension. The hallmark of the disease is that there is no etiology for the increased intracranial pressure. It typically affects obese women of childbearing age. Patients with pseudotumor cerebri may present with symptoms of increased intracranial pressure. Many practitioners do not place epidural catheters in patients with pseudotumor cerebri as there is the theoretical concern that a properly placed epidural catheter will increase intracranial pressure when local anesthetic is injected, compressing the intrathecal space and forcing CSF cephalad. There are numerous case reports of successful epidural analgesia in patients with pseudotumor cerebri. Inadvertent dural puncture is not a concern for this disease as one of the therapies is lumbar puncture.
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
Patients with abnormalities in the coagulation system or thrombocytopenia are not candidates for epidural anesthesia. The concern with these individuals is accidental puncture of a blood vessel, resulting in bleeding. If this happened, the patient would be risk for the development of an epidural hematoma, which requires surgical intervention to prevent permanent neurologic damage.
Infection at the site of injection and sepsis are contraindications to neuraxial anesthesia. Bacteria gain access to the central nervous system via the needle tip, through the blood, or via a connection from the periphery to the central nervous system (i.e., an intrathecal catheter). If the needle is placed through an infected area, there is the risk of introducing the bacteria into the epidural space for epidural anesthesia or intrathecally if there is an inadvertent dural puncture or if the plan was spinal anesthesia. The administration of antibiotics prior to the procedure does not ensure an aseptic area. If the patient is septic, the needle may introduce the bacteria into the central nervous system if there is an inadvertent dural puncture or if the plan was spinal anesthesia. Similarly, a single dose of antibiotics does not adequately remove bacteria from the bloodstream.
4. What are the patient's medications and how should they be managed in the perioperative period?
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
The performance of neuraxial anesthesia in patients taking medications that affect the coagulation system must adhere to the guidelines established by the American Society of Regional Anesthesia. If the guidelines have been followed and an inadvertent dural puncture occurs, the practitioner is confronted with a dilemma if a headache occurs. The best treatment for a PDPH is an EBP. Prior to performing an EBP, the same guidelines for neuraxial anesthesia must be followed if the patient is taking medications that affect platelets or the coagulation system.
i. What should be recommended with regard to continuation of medications taken chronically?
j. How To modify care for patients with known allergies –
k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
l. Does the patient have any antibiotic allergies- [Tier 2- Common antibiotic allergies and alternative antibiotics]
m. Does the patient have a history of allergy to anesthesia?
Documented: avoid all trigger agents such as succinylcholine and inhalational agents:
Proposed general anesthetic plan:
Ensure MH cart available [MH protocol]
Family history or risk factors for MH:
5. What laboratory tests should be obtained and has everything been reviewed?
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
During epidural anesthesia, inadvertent dural puncture is always a risk. With an incidence of 1.5%, the practitioner should have a plan when encountering a dural puncture. An inadvertent dural puncture during epidural anesthesia places the patient at risk for the development of a PDPH.
In the central nervous system, there is approximately 150 mL of CSF. PDPH is due to leakage of CSF fluid through the dural puncture. This etiology has been confirmed by magnetic resonance imaging, which showed an extradural collection of CSF in patients with PDPH. If the rate of leakage exceeds the rate of production, low CSF results in a loss of the cushion effect provided within the cranium. The decrease in CSF volume results in sagging of the brain in the cranial vault, pulling on the falx cerebri, cerebral blood vessels, and tentorium, resulting in the headache. Another component to the headache is cerebral venous dilation. Loss of CSF results in a decrease in intracranial pressure without a decrease in intravenous pressure. The pressure difference causes the cerebral veins to dilate. The component of cerebral venous dilation to PDPH is not as significant as the loss of cushion effect. This proposed mechanism accounts for the improvement of headache with the supine position, and the worsening with the upright position.
Prevent the Headache
Several techniques have been proposed for the prevention of a PDPH. No technique is 100% effective and the choice will depend upon the risks/benefits for the patient.
Cosyntropin – Cosyntropin is a derivative adrenocorticotrophic hormone that is used for an ACTH stimulation test for the diagnosis of adrenocortical insufficiency. There are several case reports of its use for the treatment of PDPH. In a study of 90 parturients who had accidental dural puncture with a 16-gauge or 18-gauge Tuohy needle, patients were randomized 30 minutes after delivery to receive either a single intravenous injection of cosyntropin 1 mg or saline. Patients were followed for 14 days. The difference in the development of PDPH was 33% in the cosyntropin group and 68.9% in the saline group. The study did not comment upon the number of patients who had accidental dural puncture with the 16-gauge needle in each group. Furthermore, the study did not comment upon who had cesarean delivery. Both of these factors affect the incidence of PDPH following accidental dural puncture and may have biased the results.
Epidural Morphine – The use of epidural morphine has been studied for the prevention of PDPH. Fifty parturients who had accidental dural puncture with a 17-gauge epidural needle were randomized to either 3 mg preservative-free morphine or saline administered epidurally twice 24 hours apart. The difference in the incidence of PDPH was 12% in the morphine group and 28% in the control group. The need for EBP was higher in the saline group (6 vs 0 patients). There was a higher incidence of side effects of pruritus, nausea, and vomiting in the morphine group. Patients were followed for 5 days after accidental dural puncture. This study had a small sample size.
Caffeine – Intravenous caffeine benzoate, 500 mg, has been advocated for the treatment of a PDPH. The use of intravenous caffeine is based upon a single study in which the assignments of the group were misplaced for some of the patients. This study was conducted in patients receiving spinal anesthesia, and there is no study assessing the efficacy of caffeine benzoate following accidental dural puncture with an epidural needle. As such, the ability to formulate conclusions from this study is difficult. The literature currently does not recommend intravenous caffeine for the prophylaxis of a PDPH
Prophylactic EBP – The injection of autologous blood into epidural space is a highly effective means to treat a PDPH. Given its effectiveness, it was postulated that the injection of blood through the epidural catheter prior to the removal of the catheter and prior to the development of a PDPH would be beneficial. In a study of 64 parturients with accidental dural puncture with a 17-gauge Tuohy needle who were randomized to prophylactic epidural blood patch or to a sham blood patch (draw blood from arm but not inject it), there was no difference in the incidence of the development of PDPH. The use of prophylactic EBP is based upon case series and the significant bias makes conclusion difficult. There is a concern with infection with a prophylactic blood patch through a catheter, although no cases have been reported.
Recumbency – The maintenance of supine position for a set time period following dural puncture has been advocated following spinal anesthesia. There is no benefit to maintaining a supine position for a set time period for dural puncture following spinal anesthesia and for accidental dural puncture during epidural anesthesia.
Intrathecal Catheter – Following accidental dural puncture during epidural anesthesia, the provider may pass a subarachnoid catheter and use it as a continuous spinal catheter. The first group to investigate the placement of an intrathecal catheter following accidental dural puncture did not find any difference in the incidence of PDPH or of the need for EBP. These authors removed the catheter immediately after delivery. Subsequent nonrandomized studies left the catheter in place for 24 hours and noticed a beneficial effect in the prevention of PDPH. The largest series of intrathecal catheters reported the experience of intrathecal catheters over a 10-year period. There was a decline in the incidence of PDPH but the results were not as impressive as previously reported. An intrathecal catheter places the patient at risk of developing meningitis and risks injection of large amounts of local anesthetic. If used, an intrathecal catheter should be clearly labeled and the number of disconnects for injection should be limited to prevent bacterial contamination. Despite a publication demonstrating that placement of an intrathecal catheter and leaving it in place for 24 hours decreases the incidence of PDPH to 9%, no subsequent study has been able to replicate the results. One of the problems with the study was that it was not randomized with choice of management of inadvertent dural puncture left to the anesthesia provider. There is no comment upon needle sizes or type of deliveries, both of which have been shown to affect the incidence of PDPH. Enthusiasm for intrathecal catheters has been decreasing. If epidural catheter placement has been difficult or if delivery is imminent, I will place an intrathecal catheter to allow for quick analgesia. If the accidental dural puncture was a misjudgment by the provider as to whether there was a change in resistance, I will re-site the epidural catheter at another location. Given the dural puncture, I would carefully titrate local anesthetic, as there are several case reports of excessive blocks from normal amounts of local anesthetic attributed to local anesthetic leaking through the dural puncture site. If a subarachnoid catheter is used, the amount of local anesthetic that is required for analgesia and anesthesia is about 1/10th that used for epidural analgesia/anesthesia.
Treatment of a PDPH
Caffeine – Caffeine is a cerebral vasoconstrictor. The animal model suggests that cerebral vessel vasodilation is a component to PDPH. Caffeine was postulated to treat the headache. There is only one study with questionable methods. As such, caffeine benzoate, 500 mg, is not recommended for the treatment of PDPH. Oral caffeine has been studied and may temporarily decrease the severity of PDPH but does not treat the headache. The dose studied was 300 mg po.
Sumatriptan – Sumatriptan is a serotonin agonist that causes cerebral vasoconstriction. There is one randomized study that failed to demonstrate a benefit to sumatriptan. The number of patients included in the study was small (10 patients). Given that the largest component to a PDPH is the traction of the meninges in the frontal and occipital areas of the skull, it is not surprising that cerebral vasoconstrictors (cerebral vasodilation is a small component of PDPH) have proved not to be beneficial in the treatment of PDPH.
EBP – In 1960, Gormley reasoned that blood may serve as a sealing material following dural puncture. He studied seven patients, one of whom was himself, and had 2-3 mL of blood injected into the lumbar epidural space at the same level as the dural puncture. While all seven patients reported relief, providers had a hard time repeating his results, most likely secondary to the amount injected. Subsequent study has determined the optimum dose to be 20-25 mL autologous blood or until the patient experiences symptoms of back pain or leg pain. The postulated mechanism for the treatment of PDPH is compression of the intrathecal space, forcing CSF cephalad. Maintenance of the therapeutic effect is attributed to clot preventing further CSF leak. The number needed to treat to result in success was calculated and was 1 (means that a provider will see a lot of effective treatments in a short time period).
The most common complication following EBP is back pain. The back pain is usually not as severe as the headache, but can persist for 2 weeks after EBP.
EBP has been reported to decrease heart rate.
EBP does not interfere with subsequent epidural analgesics/anesthetics.
There are case reports of the association of EBP and cerebral venous thrombosis. The problem is that parturients are at increased risk of development of cerebral venous thrombosis due to the hypercoagulable state of pregnancy. It is unclear if the cerebral venous thrombosis was present prior to the EBP.
An EBP may be done with the patient in the sitting or lateral decubitus position. Given the severity of the headache, the majority of providers tend to perform it in the lateral decubitus position. The performance of an EBP requires another provider to obtain the blood aseptically.
The choice of placement of an intravenous catheter is at the discretion of the provider. The advantage to an intravenous catheter is the ability to administer sedation and to treat hemodynamic abnormalities if they occur.
To perform an EBP, the level of the dural puncture or lower is chosen. One should not go higher as blood travels much more easily cephalad.
The epidural space is entered using the loss-of-resistance to saline technique. Air is discouraged as it may cross the dural puncture and worsen the headache.
Following identification of the space, a colleague obtains 25 mL of blood aseptically. The blood is slowly injected until all 25 mL is given or until the patient experiences pain in the back or legs.
What if the first EBP does not work?
The reported efficacy of an EBP is 90%. There are several possible reasons why it did not succeed:
The needle was not located epidurally.
An insufficient volume of blood was injected
The diagnosis of an PDPH is incorrect
1. If the blood patch did not work, consider other causes of headache after neuraxial anesthesia.
a. The most common cause of postpartum headache is tension/migraine.
b. Preeclampsia may result in headache postpartum.
c. Cerebral venous thrombosis may result in headache and is increased in the parturient due to the hypercoagulable state of pregnancy.
2. If the headache is consistent with a PDPH (postural component, no fever, no other associated neurological symptoms), a repeat epidural blood patch should be performed 24 hours after the prior blood patch. It most likely is due to insufficient volume of blood injected. If the headache is not consistent with a PDPH or if the second EBP does not work, a neurologic consultation should be obtained with consideration to obtaining cerebral imaging.
6. What is the author's preferred method of anesthesia technique and why?
If I have an accidental dural puncture during epidural catheter placement, subsequent management depends upon the difficulty of the placement or the urgency of the situation. If an accidental dural puncture occurs after several attempts at identifying the epidural space or if the fetal heart rate is abnormal, I would place the catheter intrathecally and manage as continuous spinal anesthesia. I do not leave the catheter in place for 24 hours after delivery due to the concerns of infection and disconnection.
If the accidental dural puncture occurs because of a misidentification of loss of resistance, I would chose to remove the needle and resite the catheter. The advantage to this approach is that the risk of accidental intrathecal injection is removed. I do not use epidural morphine because of the side effects. The cosyntropin sounds promising but I do not have experience with this technique.
If the patient develops a headache, I would choose to do a blood patch. One of the recurring themes in the literature is that delay in performing the EBP increases the chance of success. I typically do the blood patch 24 hours after the onset of headache. I try conservative measures such as bedrest and increased fluid intake. While these therapeutics have limited efficacy, they abide time until 24 hours to help improve the efficacy of the epidural blood patch.
a. Neurologic: *** Type Here.
b. If the patient is intubated, are there any special criteria for extubation?
c. Postoperative management
What's the Evidence?
Al-Metwalli, RR. “Epidural morphine injections for prevention of post dural puncture headache”. Anaesthesia. vol. 63. 2008. pp. 847-50. (A randomized study of 50 parturients who received either epidural morphine, 3 mg, twice 24 hours apart or saline. There was a lower incidence of PDPH in the epidural morphine group but there was also a higher incidence of side effects such as nausea and pruritus.)
Davies, JM, Posner, KL, Lee, LA, Cheney, FW, Domino, KB. “Liability associated with obstetric anesthesia”. Anesthesiology. vol. 110. 2009. pp. 131-9. (A review of obstetric claims in the closed claims database revealed that nerve injury is increasing in representation. PDPH remains a significant cause of malpractice claims for those in obstetric anesthesia.)
Hakim, SM. “Cosyntropin for prophylaxis against postdural puncture headache after accidental dural puncture”. Anesthesiology. vol. 113. 2010. pp. 413-20. (A randomized study of 90 parturients with accidental dural puncture who were randomized to either intravenous cosyntropin 1 mg or saline. The cosyntropin group had a lower incidence of PDPH.)
Halker, RB, Demaerschalk, BM, Wellik, KE, Wingerchuk, DM, Rubin, DI. “Caffeine for the prevention and treatment of postdural puncture headache: Debunking the myth”. The Neurologist. vol. 13. 2007. pp. 323-7. (A review of the literature examining the use of caffeine for the prevention and treatment of PDPH. The authors conclude that there is no data to support the use of caffeine for PDPH.)
Horlocker, TT, Wedel, DJ, Rowlingson, JC. “Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (3rd ed.)”. Reg Anesth Pain Med. vol. 35. 2010. pp. 64-101. (The guidelines established by ASRA concerning neuraxial anesthesia in patients receiving anticoagulants. This document should be reviewed prior to neuraxial anesthesia in any patient receiving medications that affect coagulation.)
Ko, JY, Leffert, LR. “Clinical implications of neuraxial anesthesia in the parturient with scoliosis”. Anesth Analg. vol. 109. 2009. pp. 1930-41. (A great review of parturients with scoliosis who request neuraxial anesthesia.)
Kueper, M, Goericke, SL, Kastrup, O. “Cerebral venous thrombosis after epidural blood patch: coincidence or causal relation? A case report and review of the literature”. Cephalalgia. vol. 28. 2008. pp. 769-773. (The hypercoagulable state of pregnancy increases the risk of cortical vein thrombosis.)
Scavone, BM, Wong, CA, Sullivan, JT, Yaghmour, E, Sherwani, SS, McCarthy, RJ. “Efficacy of a prophylactic epidural blood patch in preventing postdural puncture headache in parturients after inadvertent dural puncture”. Anesthesiology. vol. 101. 2004. pp. 1422-7. (An nicely conducted study that demonstrates that the prophylactic injection of blood through an epidural catheter does not prevent the development of headache.)
Stella, CL, Jodicke, CD, How, HY, Harkness, UF, Sibai, BM. “Postpartum headache: is your work-up complete?”. Am J Obstet Gynecol. vol. 196. 2007. pp. 318.e1-7. (This article is an outstanding review of the etiologies of postpartum headaches.)
Van de Velde, M, Schepers, R, Berends, N, Vandermeersch, E, De Buck, F. “Ten years of experience with accidental dural puncture and post-dural puncture headache in a tertiary obstetric anaesthesia department”. Int J Obstet Anesth. vol. 17. 2009. pp. 329-35. (Despite many advocating an intrathecal catheter for the prevention of a PDPH, this series suggests that an intrathecal catheter helps but not to the extent that had previously been reported in the literature. Given these results, the benefits do not clearly outweigh the risk making the decision to place an intrathecal catheter individualistic based upon other additional criteria, such as urgency and difficulty of placement.)
van Kooten, F, Oedit, R, Bakker, SLM, Dippel, DWJ. “Epidural blood patch in post dural puncture headache: a randomized, observer-blind controlled clinical trial”. J Neurol Neurosurg Psychiatry. vol. 79. 2008. pp. 553-8. (The first randomized study to prove the effectiveness of EBP.)
Vilming, ST, Kloster, R, Sandvik, L. “When should an epidural blood patch be performed in postlumbar puncture headache? A theoretical approach based on a cohort of 79 patients”. Cephalgia. vol. 25. 2005. pp. 523-7. (This study investigated the optimal time to perform an EBP. Delaying 24 hours after the onset of symptoms improved the success rate.)
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- What the Anesthesiologist Should Know before the Operative Procedure
- 1. What is the urgency of the surgery?
- What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- b. Cardiovascular system
- c. Pulmonary
- d. Renal-GI:
- e. Neurologic:
- f. Endocrine:
- g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
- 4. What are the patient's medications and how should they be managed in the perioperative period?
- i. What should be recommended with regard to continuation of medications taken chronically?
- j. How To modify care for patients with known allergies -
- k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
- l. Does the patient have any antibiotic allergies- [Tier 2- Common antibiotic allergies and alternative antibiotics]
- m. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- 6. What is the author's preferred method of anesthesia technique and why?
- a. Neurologic: *** Type Here.
- b. If the patient is intubated, are there any special criteria for extubation?
- c. Postoperative management