Most people recover from major surgical procedures in a predictable fashion. However, as anyone who manages these patients knows, there are always a few outliers. A negative laparotomy patient who has an ileus for over a week. Hip fracture patients who take forever to get out of bed.
We usually chalk this up to human variability or varying degrees of frailty. But could there be more to it? Could it even be predictable?
A group of anesthesiologists and immunologists at Stanford used a new cell-mapping technique to attempt to correlate immune system signatures in blood during the first hours after operation with recovery time. They used a technique called mass cytometry, which flushes different tagged antibodies through a blood sample. This allowed the investigators to determine which immune cells were present, as well as which signalling molecules were being produced.
Here are the factoids:
- 32 patients undergoing hip replacement surgery were studied at various times up to 6 weeks after the procedure
- Antibodies directed at 21 cell surface proteins and 10 intracellular proteins associated with the immune response
- Recovery from fatigue, pain, and recovery of hip motion were quantified using validated objective scoring tools
- As expected, there was a considerable amount of variability in recovery parameters among the patients
- Activation of CD14+ monocytes accounted for 40-60% of the variability in recovery times observed
- Patients with higher activations were more likely to take at least 3 weeks to recover. Those with low activation recovered more quickly.
Bottom line: This is heady stuff, and it is based on a very small group of patients. However, it does suggest that immune system overdrive may be responsible for more evil: slow recovery from surgery. At some point, it may be possible to predict recovery time from a preop blood test. This would be very helpful to know before surgery, and at some point may allow us to give drugs that blunt these processes and speed up surgical recovery.
Reference: Clinical recovery from surgery correlates with single-cell immune signatures. Science Translational Medicine 6(255):255ra131 1-12, 2014.