Critical Care Medicine doctor at Monroe Carell Jr. Hospital at Vanderbilt, Dr. Michael Wolf talks about ketamine possibly helping treat kids with TBIs.
Interview conducted by Ivanhoe Broadcast News in 2023.
What has ketamine traditionally been used for?
Wolf: Ketamine is an anesthetic, meaning it’s a drug that’s used to put people to sleep when they have to undergo surgery or a potentially painful or distressing procedure. It’s also used as a sedative in the intensive care unit when folks are critically ill and need medicine to help them be comfortable throughout their treatment. In the setting of traumatic brain injury, ketamine is a drug that we’ve previously thought was contraindicated; meaning you shouldn’t use it because there was a risk associated with increasing the pressure inside the patients’ skulls.
There has been a recent change of opinion towards the subject, is this correct?
Wolf: Yes. Traditionally, ketamine has been thought to be associated with a risk in patients who’ve had traumatic brain injury because it was said to increase pressure inside the skull which is called intracranial pressure. But more recently, there have been studies that have contradicted those findings and led us to think that ketamine actually may be safe to give to patients. This represents a big opportunity to study the effects of ketamine in patients who’ve had traumatic brain injury because it may represent a really potentially useful treatment.
How does it reduce pressure inside of the skull and why did doctors once believe it could raise intracranial pressure?
Wolf: Children who’ve had severe head injuries are critically ill. We take care of them in the intensive care unit, and they require significant treatment including breathing tubes that have central lines coming out of them. They’re given multiple medications and a team including multiple doctors, surgeons, and nurses. We monitor the pressure inside their head because we’re very concerned when it becomes high. One of the reasons that pressure can become high is if a patient starts to wake up and become distressed or experience pain. We often give medicines called sedatives in order to prevent a patient from getting agitated. Unfortunately, a lot of those sedatives have side effects. One of the major side effects of sedatives is low blood pressure and ketamine is a sedative that has less of a low blood pressure side effect. We think it may represent a really exciting and potentially useful drug for these patients.
Thank you for the clarity. A study was done where thirty-three patients were analyzed and some received ketamine. What are the comparison results?
Wolf: This is a really preliminary study where we’ve been able to look back in time retrospectively at patients who received ketamine with severe traumatic brain injury. We’ve looked at the pressure in their heads over time through the monitors that our surgeons set in place. We’ve then used that data to find some really interesting preliminary results, which is that in patients who received ketamine, their intracranial pressure did not go up. In fact, when some of the patients got ketamine at a time when the pressure was already high, the pressure went down. These are really interesting preliminary findings that make us very excited about the future potential for ketamine. What we need to do is go forward and study these effects in a larger number of patients in real time as opposed to going back in time retrospectively.
The initial injury time is critical in avoiding future impairments. How does ketamine work to minimize ongoing damage to their brains?
Wolf: After a severe head injury, a child’s brain has been injured initially by say a car crash or being hit by some other reason. After that initial injury, there is risk for ongoing damage to the brain and that’s why we take care of these children so carefully in the intensive care unit. Continuously monitoring all vital sins to lower the pressure in their heads very carefully. The aim is to limit the ongoing damage to their brain that can occur after injury. To combat that we give medications to ensure their comfort and to try and prevent their intracranial pressure from going up. Ketamine is a medication that we think could potentially be used to keep patients comfortable in a way that doesn’t raise their intracranial pressure and also keeps their blood pressure more stable.
What led you to the, now proven, ketamine theory?
Wolf: There were a couple of studies in the 1870s surrounding ketamine that led researchers to the concern that ketamine may raise the pressure inside your skull. Those were a couple of small studies done in a small number of patients. In the decades since then, there have been multiple studies that have contradicted those findings and have shown that the pressure most likely doesn’t go up after ketamine. In fact, in some cases it’s gone down. We’ve had limited studies in children with brain injuries because it’s harder to do studies that affect children.
Why is that?
Wolf: Doing research to improve the care of critically ill children is really important but also very challenging. Unlike adults, we take care of children in smaller numbers, and they can be a lot sicker. We’re very careful about how we do research in children because we never want to put them at risk. We’ve been so fortunate to look at data from critically ill children and use the information to try to improve the care of future children with traumatic brain injury. This is critically important for us because we are hoping to improve the care of children with traumatic brain injury for generations to come. Unfortunately, right now, the number of treatments that are effective in treating traumatic brain injury are precious few. If ketamine is found to be an effective treatment for children with severe head injury, that could be a game changer and could add one more tool to a very limited toolkit to help us take care of these children.
Absolutely. Can you tell us about Will’s specific injuries and share a fact about him?
Wolf: I first learned about Will’s injury over the phone. I was actually called by a colleague and friend at Vanderbilt who said, “I have this friend of a friend who’s about to be your patient and they’re out of town and they’ve had this horrible injury.” From there I started to get in touch with our neurosurgeons and with the hospital Will was staying in. I learned that he’d had a severe head injury with a big hemorrhage inside of his head, just outside of his brain. It was so large and severe that it was compressing his brain and had become a life-threatening injury. In that moment, everyone’s focus was how to get Will to Vanderbilt safely. It took a big team, but with the help of neurosurgeons, the intensive care unit, the transport team, and trauma surgeons, we all worked together to get Will safely to Vanderbilt. When he arrived he was very concerning. Our neurosurgeons placed a monitor inside of his brain and his pressure from the very start was severely elevated. He needed multiple treatments to get it to a safe level. Ultimately, he required a big surgery that our neurosurgeons performed in order to relieve the pressure in his brain.
How’s Will doing now in the long-term prognosis?
Wolf: It has been incredible to see the way Will has progressed. He has now been able to gain skills with walking. He has been working on eating, talking, and he is just the pride and joy of his family and his community. Seeing him flourish and recover from this, and really thrive, has been tremendous. It’s why we do this.
Do you think Will is going to have a positive future ahead of him? Physically, will he be okay?
Wolf: I think Will is going to have a really great life ahead of him. His family, his community, and his spirit has been such an active component in his recovery. He has had such an amazing spirit through all of it and an amazing attitude. The way he’s leaned into the treatments that he needs to improve. It’s really been an inspiration.
END OF INTERVIEW
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