Local anaesthetic systemic toxicity

Local anesthetic systemic toxicity (LAST) is a life-threatening adverse event that can occur after the administration of local anesthetic drugs through a variety of routes. In my craniosacral therapy practice, I have treated a few clients (mothers and their babies) who had this unexpected and frightening experience during their birth. I have also personally experienced LAST during a routine dental procedure. It is an overwhelming experience! I found out what happened to me via google so I wanted to provide an article for others who are trying to make sense of their experience. LAST effects the body, the nervous system and is an emotional experience (for babys inutero too). Overwhelming experiences imprint on our tissues and nervous systems and craniosacral therapy can play a role in holistically treating any after effects of the experience.

Local anesthetic (LA) is used to numb tissues so that minor procedures can be performed without using general anaesthetic (GA). LA agents such as Lignocaine or Bupivacaine are used during dental procedures, and within the maternity system to stitch up episiotomy wounds and in epidurals. “Local” means it stays within the area that is administered, whereas “systemic” means it affects the rest of the body. Toxicity occurs when too much is administered or when the LA is inadvertently injected into the bloodstream, affecting the nervous system or cardiovascular system¹. A normal dose can cause an adverse reaction if it goes into a blood vessel and it can be fatal. During pregnancy and birth we also need to consider the impact on the baby as medications administered to the mother are transferred to the fetus to varying degrees depending on the agent used.

Signs/symptoms of LAST:

What does it feel like?

Without being overly dramatic, it feels like dying². Both of the mothers I worked with were in active labour and birth was imminent. One mother explained how during an episiotomy, the obstetrician accidently injected the LA into a blood vessel. She lost consciousness but was able to eventually give birth vaginally. She told me – “I remember thinking, I am going to die and looking at my partner thinking he’s going to have to raise this baby alone”. Another mother ended up needing an emergency c-section under GA, when the LA was injected into the blood stream inadvertently during placement of an epidural. She said “I thought I was going to die”. In my experience I felt like I was having a heart attack and my heart was going to suddenly stop.

Many LA’s contain epinephrine which is basically adrenaline (the “fight or flight” hormone). It is added because it tightens blood vessels with the aim of preventing dilution of the LA agent away from the local area – prolonging the anaesthesia. It’s the same ingredient used in an EpiPen or to kick start the heart during CPR. Epinephrine is generally given under the skin or into muscle and only ever injected intravenously in emergency situations e.g. cardiac arrest, anaphylaxis. I wondered if my experience of increased heart rate was more due to the epinephrine?³

LAST is an unexpected medical phenomenon and physiologically a traumatic experience. But trauma isn’t simply what happens to us, it can be exacerbated by the way we are treated – if we felt unsupported during an overwhelming time.

“Trauma is not what happens to us, but what we hold inside in the absence of an empathic witness.” 

Peter Levine

Adults, who experience something as distressing as LAST, may be fortunate enough to have their experience acknowledged. As with all traumatic experiences, if the event is acknowledged for what it is and the person feels supported through it, our bodies will integrate the experience and move on. The body does not need to hold the imprint. Some may not get the chance to propery debrief. There is the possibility that professionals may not recognise or accept this medical error – perhaps due to fear of litigation or they may simply assume the person is having a panic attack⁴

Both of the mothers I worked with had their experience named, validated and debriefed – even if there was initial confusion about what was happening in the moment. But what of the baby’s experience? Babies certainly aren’t recognised as being impacted by the experience. Remember, inutero they share the same blood supply as their mother and they share similar emotional experiences.

Lignocaine is considered the safest LA to use during pregnancy but accidental injection into the bloodstream (or overdose) can result in an increased risk of fetal cardiac and central nervous system toxicity. And with epinephrine, they may experience “nonreassuring fetal heart tones due to decreased uterine blood flow, especially when the fetus is already compromised. Knowing that babies are conscious beings having their own experience of birth, they may also feel like they are going to die. We do need to acknowledge the impact of these kinds of events on the baby – physical and emotional. The babies I have treated have needed support to bring their nervous system out of fight or flight and release the fear imprint.

My LAST experience….

A couple of years ago I went to the dentist for a routine filling and as the dentist was injecting the LA, I felt a feeling of something dispersing throughout my head and suddenly my heart started pounding in a very erratic way, I became dizzy and my vision started tunnelling. My body started shaking. I barely managed to tell her to stop. The dentist thought I was having a panic attack (I am an ex-registered nurse and I am not scared of dental procedures or needles). Then she thought I might have low blood sugar and tried to give me something to eat and drink. Afterwards I insisted that it was related to the anaesthetic, that I felt the dispersal of the medication throughout my head but I was ignored. I was extremely shaken up and needed to sit in my car for some time before driving home. and later, at home, I needed to have a big cry to release some of the stress from the experience. Online, I discovered forums of people who had had a similar experience with the theory that the LA had inadvertantly gone into the bloodstream. At the next dental visit, my dentist was still unable to acknowledge this so I made a complaint and changed dentist. I was left feeling really angry about how I was treated (I dont blame them for the event – mistakes happen). I eventually scheduled a cranio treatment to support the release of this medical trauma from my system.

In conclusion:

Healing is always possible! But first acknowledgement needs to happen. Craniosacral therapy is one way to provide acknowledgement for the body and person. It is a gentle, holistic therapy that acknowledges and facilitates release of imprints from earlier, difficult experiences. It works with emotional and physical layers and with the nervous system to shift out of dysregulated states. It is a good idea to treat both mother and baby if they are unfortunate to experience LAST during their pregnancy or labour. Rebalancing both systems contributes to optimal wellbeing.

Footnotes:

1. Intravenous infusion of a lipid emulsion has become part of the treatment for systemic toxicity from LAs, particularly for refractory cardiac arrest.
2. I now request that any LA I receive, is without Epinephrine after this experience.
3. Near death experiences may lead to symptoms of posttraumatic stress disorder (PTSD) like flashbacks, nightmares, reactivity or avoidance of situations that may bring back the trauma.
4. The small amount of epinephrine in dental cartridge was once thought to be incapable of significantly increasing epinephrine blood levels after local anaesthetic administration. Most of the cardiovascular stimulation reported after local anaesthesia administration was thought to be due to patient fear and anxiety or the pain of injection. However, studies have found that the epinephrine in as little as two cartridges can significantly increase circulating epinephrine levels.