Epidural AnesthesiaTechniques such as epidural analgesia and epidural anaesthesia employ this route of administration. The epidural route is frequently employed by certain physicians and nurse anaesthetists to administer local anaesthetic agents, and occasionally to administer diagnostic e. Epidural techniques frequently involve injection of drugs through a catheter placed into the epidural space. The injection can result in a loss of sensation —including the sensation of pain —by blocking the transmission of signals through nerve fibres in or near the spinal cord. Spinal anaesthesia is a technique whereby a local anaesthetic drug epidural steroid injection for delivery injected into the cerebrospinal fluid.
Using Epidural Anesthesia During Labor: Benefits and Risks
Techniques such as epidural analgesia and epidural anaesthesia employ this route of administration. The epidural route is frequently employed by certain physicians and nurse anaesthetists to administer local anaesthetic agents, and occasionally to administer diagnostic e. Epidural techniques frequently involve injection of drugs through a catheter placed into the epidural space. The injection can result in a loss of sensation —including the sensation of pain —by blocking the transmission of signals through nerve fibres in or near the spinal cord.
Spinal anaesthesia is a technique whereby a local anaesthetic drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anaesthesia, and lay people often confuse the two techniques.
Injecting medication into the epidural space is primarily performed for analgesia. This may be performed using a number of different techniques and for a variety of reasons. Additionally, some of the side-effects of epidural analgesia may be beneficial in some circumstances e. When a catheter is placed into the epidural space see below a continuous infusion can be maintained for several days, if needed. Epidural analgesia may be used:.
The epidural space is more difficult and risky to access as one ascends the spine because the spinal cord gains more nerves as it ascends and fills the epidural space leaving less room for error , so epidural techniques are most suitable for analgesia anywhere in the lower body and as high as the chest. They are usually much less suitable for analgesia for the neck, or arms and are not possible for the head since sensory innervation for the head arises directly from the brain via cranial nerves rather than from the spinal cord via the epidural space.
The epidural space is the space inside the bony spinal canal but just outside the dura mater "dura". In contact with the inner surface of the dura is another membrane called the arachnoid mater "arachnoid".
The cerebrospinal fluid that surrounds the spinal cord is contained by the arachnoid mater. In adults, the spinal cord terminates around the level of the disc between L1 and L2 in neonates it extends to L3 but can reach as low as L4 , below which lies a bundle of nerves known as the cauda equina "horse's tail".
Hence, lumbar epidural injections carry a low risk of injuring the spinal cord. Insertion of an epidural needle involves threading a needle between the bones, through the ligaments and into the epidural potential space taking great care to avoid puncturing the layer immediately below containing CSF under pressure. Procedures involving injection of any substance into the epidural space require the operator to be technically proficient in order to avoid complications.
Proficiency can be gained using bananas or other fruits as a model. The subject may be in the seated, lateral or prone positions. The iliac crest is a commonly used anatomical landmark for lumbar epidural injections, as this level roughly corresponds with the fourth lumbar vertebra, which is usually well below the termination of the spinal cord.
The Tuohy needle, designed with a degree curved tip and sidehole to redirect the inserted catheter vertically along the axis of the spine, is usually inserted in the midline, between the spinous processes.
When using a paramedian approach, the tip of the needle passes along a shelf of vertebral bone called the lamina until just before reaching the ligamentum flavum and the epidural space. Along with a sudden loss of resistance to pressure on the plunger of the syringe, a slight clicking sensation may be felt by the operator as the tip of the needle breaches the ligamentum flavum and enters the epidural space.
Practitioners commonly use air or saline for identifying the epidural space. However, evidence is accumulating that saline is preferable to air, as it is associated with a better quality of analgesia and lower incidence of post-dural-puncture headache. This may be done using a portable ultrasound scanner, or with fluoroscopy moving X-ray pictures.
After placement of the tip of the needle into the epidural space, a catheter is often threaded through the needle. The needle is then withdrawn over the catheter. The catheter is a fine plastic tube, through which anaesthetics may be injected into the epidural space.
Many epidural catheters have a blind end, and three or more orifices along the shaft near the distal tip far end of the catheter. This not only disperses the injected agents over more spinal levels, but also reduces the incidence of catheter blockage. Choice of agents A person receiving an epidural for pain relief may receive local anaesthetic, an opioid , or both.
Common local anaesthetics include lidocaine , mepivacaine , bupivacaine , ropivacaine , and chloroprocaine. Common opioids include hydromorphone , morphine , fentanyl , sufentanil , and pethidine known as meperidine in the United States. These are injected in relatively small doses, compared to when they are injected intravenously.
Other agents such as clonidine or ketamine are also sometimes used. For a short procedure, the anaesthetist may introduce a single dose of medication the "bolus" technique. This will eventually dissipate. Thereafter, the anaesthetist may repeat the bolus provided the catheter remains undisturbed.
For a prolonged effect, a continuous infusion of drugs may be employed. There is some evidence that an automated intermittent bolus technique provides better analgesia than a continuous infusion technique, though the total doses are identical. Level and intensity of block Typically, the effects of the epidural block are noted below a specific level on the body. This level may be determined by the anaesthetist. A high insertion level may result in sparing of nerve function in the lower spinal nerves.
For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the perineum area around the genitals or pelvic organs. The intensity of the block is determined by the concentration of local anaesthetic solution used. The catheter is usually removed when the subject is able to take oral pain medications.
Catheters can safely remain in place for several days with little risk of bacterial infection,    particularly if the skin is prepared with a chlorhexidine solution. Epidural analgesia provides rapid pain relief in most cases. It is more effective than opioids and other common modalities of analgesia in childbirth. The medication levels are very low to decrease the side effects to both mother and baby.
When in labor the mother does not usually feel pain after an epidural but they do still feel the pressure. Women are able to bear down and push with contractions. In a Cochrane review which included 38 randomized controlled studies involving women, wherein all but five studies compared epidural analgesia with opiates, epidural analgesia in childbirth was associated with the following advantages and disadvantages: However, the review found no difference in overall Caesarean delivery rates, nor were there effects on the baby soon after birth.
Also, the occurrence of long-term backache was no different whether an epidural was or was not used. Though complications are rare, some women and their babies will experience them. Some side effects for the mother include headaches, dizziness, difficulty breathing and seizures.
The child may experience slowed heartbeat, temperature regulation issues and there could be high levels of drugs in the child's system from the epidural. Differing outcomes in frequency of Cesarean section may be explained by differing institutions or their practitioners: Regarding early or late administration of epidural analgesia, there is no overall difference in outcomes for first-time mothers in labor.
Epidurals other than low-dose ambulatory epidurals  preclude maternal movement, but "walking, movement, and changing positions during labor help labor progress, enhance comfort, and decrease the risk of complications.
One study concluded that women whose epidural infusions contained fentanyl were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks. If this were the case, then early epidural analgesia which avoided the need for pethidine would be expected to improve breastfeeding outcomes rather than worsen them. Traditional epidural for labor relieves pain reliably only during first stage of labor uterine contractions until cervix is fully open.
It does not relieve pain as reliably during the second stage of labor passage of the fetus through the vagina. Despite these benefits, no survival benefit has been proven for high-risk individuals. The caudal approach to the epidural space involves the use of a Tuohy needle, an intravenous catheter, or a hypodermic needle to puncture the sacrococcygeal membrane.
The caudal epidural technique is often used in infants and children undergoing surgery involving the groin, pelvis or lower extremities. In this population, caudal epidural analgesia is usually combined with general anaesthesia since most children do not tolerate surgery when regional anaesthesia is employed as the sole modality. For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a spinal anaesthetic with the post-operative analgesic effects of an epidural.
This is called combined spinal and epidural anaesthesia CSE. The practitioner may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space.
The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal.
This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space. Epidural steroid injection may be used to treat radiculopathy , radicular pain and inflammation caused by such conditions as spinal disc herniation , degenerative disc disease , and spinal stenosis.
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. Epidural analgesia typically involves using the opiates fentanyl or sufentanil, with bupivacaine or one of its congeners. Fentanyl is a powerful opioid with a potency 80 times that of morphine and side effects common to the opiate class.
Sufentanil is another opiate, 5 to 10 times more potent than Fentanyl. Bupivacaine is markedly toxic if inadvertently given intravenously, causing excitation, nervousness, tingling around the mouth, tinnitus, tremor, dizziness, blurred vision, or seizures, followed by depression: Bupivacaine has caused several deaths by cardiac arrest when epidural anaesthetic has been accidentally inserted into a vein instead of the epidural space.
Sensory nerve fibers are more sensitive to the effects of the local anaesthetics than motor nerve fibers. This means that an epidural can provide analgesia while affecting muscle strength to a lesser extent.
For example, a labouring woman may have a continuous epidural during labour that provides good analgesia without impairing her ability to move. If she requires a Caesarean section, she may be given a larger dose of epidural local anaesthetic.
The larger the dose used, the more likely it is that side effects will be evident. For example, very large doses of epidural anaesthetic can cause paralysis of the intercostal muscles and thoracic diaphragm which are responsible for breathing , and loss of sympathetic nerve input to the heart, which may cause a significant decrease in heart rate and blood pressure.
This may require emergency intervention, which may include support of the airway and the cardiovascular system. Because of this, a urinary catheter is often placed for the duration of the epidural infusion. People with continuous epidural infusions of local anaesthetic solutions typically ambulate only with assistance, if at all, in order to reduce the likelihood of injury due to a fall.
Large doses of epidurally administered opioids may cause troublesome itching , and respiratory depression. If dural puncture is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid.
This may result in a high block, or, more rarely, a total spinal , where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes seizures.