Someone (thank you Mona Lisa) sent me a link to an article about a nightmare c-section where a woman felt the entire surgery and asked these questions:
Why does this happen? Can it be fixed mid surgery, or does the anesthesiologist have their hands tied? Several mothers have commented on Navel Gazing Midwife saying this has happened to them, or they know someone it’s happened to. How common is this? What sort of disciplinary action should the anesthesiologist face? Or is this just an accepted risk of the procedure?
We are talking about neuraxial block failure – ie a spinal or epidural block that is inadequate for the surgery. First we need to understand what neuraxial blocks are and the difference between the different types. A neuraxial block is an injection of local anesthetic and narcotic into the intrathecal space (a spinal, the medication goes into the fluid or CSF that surrounds the spinal cord) or the epidural space (an epidural, the medication goes into a fat-filled space outside of the membranes that surround the spinal cord and spinal fluid). A spinal interrupts nerve transmission in the spinal cord itself, an epidural interrupts nerve transmission in the nerve roots as they exit from the spinal column through the epidural space. A spinal requires less volume of drug because the interthecal space is smaller. It also has a faster onset compared to an epidural. For an epidural to work for a c-section, many levels of nerve roots need to be frozen. The medication has to spread up and down in the epidural space and enough volume has to be injected for it reach all the nerve roots that carry sensation to the surgical site. Although the incision for a c-section is usually confined to a small area, the freezing has to work on the entire peritoneum (the membrane lining the abdominal cavity, not the perineum which is the skin and muscle located between your vagina and anus).
Above: an epidural catheter in the epidural (above the dura) space. The dura is not punctured.
A spinal/ intrathecal injection. The dura is punctured and the injection is into the CSF.
Different neuraxial blocks have gone in and out of fashion over the years due to complications and availability of different medications. It was discovered (before my time) that certain preparations of lidocaine, when injected into the interthecal space, were causing neurological irritation and damage in a small proportion of patients (http://www.jcafulltextonline.com/article/S0952-8180(00)00186-0/abstract). This could be prevented by using an epidural injection to keep the lidocaine outside of the interthecal space. Epidurals became more popular compared to spinals for a short time. There were also some thoughts about an epidural being beneficial because you could titrate the block through a catheter rather than just placing a single shot injection which theoretically gives the anesthesiologist greater control with fewer side effects. However, bupivacaine came out, then ropivacaine and both could be used in the interthecal space without causing problems with transient neurologic syndrome and cauda equina…and since a spinal injection is simpler, now spinals are used for most elective or planned c-sections as well as for urgent c-sections in labouring women who don’t have an epidural. It is also possible to do a combined spinal-epidural or CSE where an epidural catheter is inserted just after an interthecal injection. This allows a spinal block to be extended with an injection through the epidural catheter if the surgery lasts longer than the spinal.
Neuraxial blocks are preferred over general anesthesia for most c-sections (except the super super emergent) because we recognize that birth is a special moment for the family and that most women would prefer to be awake for the birth of their child. An awake mom also allows the presence of a support person so generally the child’s other parent gets to be present for the birth too. Secondly, general anesthetic agents are transferred to the fetus and can cause some depression, although, to be honest, with modern agents and techniques, this doesn’t appear to be much of a problem. A neuraxial anesthetic allows us to avoid having to instrument the pregnant airway – briefly, putting a breathing tube down the larynx of a pregnant woman and getting it out safely at the end of the procedure is not straightforward as there is a higher incidence of failed intubation, hypoxia, airway obstruction and serious morbidity and mortality due to that compared to non-pregnant women. Maternal mortality is lower after a c-section under neuraxial compared to general as is morbidity. There is less blood loss, earlier mobilization, breastfeeding and return of gut function after neuraxial compared to general.
The failure rate of a spinal injection for c/s is 0.5-4% while the failure rate for an epidural is a bit higher at 4-13% (Pan et all, Int J Obstet Anesth 2004; 13:227-33). The failure rate for epidurals is higher because they are often placed during labour and may migrate out of the epidural space. The failure rate for an epidural placed in the OR in a controlled fashion just prior to the c-section is probably less than the above quoted rate. Neuraxial blocks take away pain and temperature sensations and may take away motor control. However, they do not take away the sensations of pushing and pulling that occur during the surgery and that is completely normal and does not mean that the block is not working.
When a neuraxial block fails to provide adequate anesthesia for a c-section there are several possibilities. Maybe there are anatomical abnormalities that prevent spread. Maybe the drug wasn’t injected into the right anatomical space – the techniques are “blind”. Maybe a dosing error was made and not enough drug was injected. Maybe a drug error was made and the wrong drug was injected. Maybe the drug was a bad batch. We’ve had some troubles with 0.5% bupivacaine that we use in the spinals for major joint replacements. Turns out trucking it across Canada without climate control caused some breakdown of the drug. Maybe it was working but the block has regressed faster than anticipated or the surgery has lasted longer. Maybe the block is working perfectly but my patient is having a panic attack.
Maybe we will never know why it didn’t work.
The first step that you should expect and insist on as a patient is that when you voice your concerns about inadequate anesthesia, that you are listened to and your discomfort is acknowledged. Then some steps should be taken to fix the problem. These steps depend on the urgency of the c-section and the stage of the surgery. If the surgeon hasn’t begun and your baby is happy, then perhaps a little more time will allow the block to develop more or maybe it would be a good idea to repeat the injection, or put in an epidural to extend an inadequate spinal…A second intrathecal injection puts you at risk of getting a really high spinal which might compromise your breathing or even cause unconsciousness so your anesthesiologist may not feel it is safe. Sometimes, if it’s truely elective, we can wait for a partial spinal to regress before we repeat it. If your epidural doesn’t work perfectly for labour (ie lots of top-ups and lots of medication required, unilateral or patchy), I personally usually don’t bother trying to top it up for a c-section…I pull it out and put in a spinal because it is more reliable. Putting in a spinal due to inadequate anesthesia after topping up an epidural also might increase the risk of a high spinal as the swollen epidural space “squishes” the interthecal space.
If the surgeon has begun the operation, then we can’t sit you up or roll you over to repeat a neuraxial injection because that compromises the sterility of the surgical site. The choice then is a general anesthetic, or if your discomfort isn’t severe and something you can live with, then perhaps some local anesthetic injected by the surgeon, an alteration in the surgical technique (less tugging, no exteriorization of the uterus) and/or a small amount of sedatives and narcotics via the IV will get you through the experience. If you chose the latter, be aware you can change your mind and request a switch to a general anesthetic.
Maybe if things are pretty scary and your baby has to come out right away, conversion to general anesthesia is the only way to go.
In the third world where anesthesia services are not available, C-sections are truly heroic life-saving procedures and frequently done with local anesthetic alone.
In terms of disciplinary action for an epidural or spinal that doesn’t work…all physicians, anesthesiologists not accepted, are required to treat their patients with dignity and compassion, to do no harm and to respect their patient’s autonomy. Behaviour to the contrary can be addressed directly with the physician, through the patient complaint department at the hospital, via the provincial college of physicians and surgeons in Canada (or I suppose the state licensing authority in the US) or via legal channels.
When I discuss anesthetic options with my patients and we are discussion a spinal or epidural block, I always mention the possibility of block failure as well as methods to address it such as conversion to general anesthesia. When a block fails, there is a human tendency to dismiss it…oh, well, the patient is just nervous, or, well, it’s not that bad, right? Clearly she’s just feeling tugging, not pain and tugging is normal. But that doesn’t do either myself or the patient any service. They will get increasingly distressed and I’m just putting off the inevitable. We need to face our failures head on and deal with them and fixing the problem of a neuraxial block that doesn’t provide adequate anesthesia for a c-section requires time – time for a discussion to occur with the patient regarding options and preferences, and time to repeat the injection or set up for and establish a safe general anesthetic. Best to fix the problem as soon as it is identified.