Recovery time from surgery foretold
If you or someone close to you has ever had major surgery, you will know that it's a big shock to the system and takes time to recover. But it's not the same for everyone, and while some people seem to spring back quickly, others end up exhausted and weak for a while.
Anaesthetist Brice Gaudilliere and his colleagues at Stanford University in California think they've figured out what causes these differences, Kat Arney spoke to Brice about how this discovery could lead to new tests to help predict recovery time or even new drugs to help you get back on your feet more quickly.
Brice - There's a nice theory about the biology of the response to surgery or trauma. I can take you back forty-thousand years ago when the cavemen were fighting the saber-tooth tiger and the tiger sometimes would just chop one of their legs or arm, and that was a major injury like surgery. Well the body developed this way to deal with a major injury by producing a profound inflammatory response, fighting off pathogens and starting the wound healing process. But interestingly, after that there's an anti-inflammatory response where the body is actually immunosuppressed, and associated with this immunosuppressed state is a sickness behaviour. That behaviour keeps the caveman inside the cave, you know, away from the tiger, away from danger, it has an evolutionary purpose, but that's also what, you know, we're measuring when we're measuring recovery. It's this sickness behaviour that you have to go through before becoming, you know, coming back to your baseline and being well again.
Kat - So, basically, our immune system just after the surgery, kicks into action and then afterwards, it gets damped down and this is what's making us feel bad.
Brice - You know, this theory's been around for quite a while, maybe 20 years. But it'spretty interesting that the immunological bases of this theory are really not understood and that's the other question that we wanted to tackle. What are the cells that are important in this immune response to surgery or to trauma in general? And what do these cells do? And how do you relate what the cells are doing, the immune cells I'm talking about, how do you relate what they are doing with how patients recover?
Kat - Tell me a little bit about what you did? What were you measuring in patients to try and find out what's the difference between them?
Brice - The surgery was the hip replacement, which is considered a middle range to major surgery with lots of blood loss - significant trauma - and we studied a total of 32 patients. Clinically, we were following these patients every three days for a period of six weeks, and we're measuring very precisely their recovery using three parameters - fatigue, pain, and function. But at the same time, and that's where the approach that we took was quite novel, we used a new technology called CyTOF to profile the immune response of these patients with very, very high resolution, and this CyTOF thing, all it does is to measure many, many parameters in every cell present in a blood sample and there are millions of these cells, about two million in each blood sample. This allows us to know what kind of cell it is, but also what the cell is thinking.
Kat - What did you find in these patient's immune systems?
Bryie - The most dramatic finding was the expansion of a particular cell type. This particular cell type is present at a very low frequency in your blood at baseline. You can barely measure them. And they expand dramatically after surgery, as much as tenfold. Not only that, but their activity level within the first 24 hours after surgery, those were strongly associated with how quickly a patient would recover from surgery. So, if you measure their activity level shortly after surgery, you can predict what the patient will look like, weeks afterwards.
Kat - What's the practical application? What can you do with this now that will help people?
Brice - So, several things. First out, I wouldn't dismiss the information that you get from being able to tell how long it will take to recover but because we're getting at the molecular aspects of this immune response, now you can start thinking about different ways to target these cells pharmacologically and see if you can modulate their activity and intervene to improve patient's recovery.
Kat - That's Brice Gaudilliere at Stanford University in California.