Acute compartment syndrome (ACS) is a surgical emergency that threatens limb viability
and can develop in patients on extracorporeal membrane oxygenation (ECMO). ACS typically
develops as a complication secondary to peripheral arterial cannulation and is more
common in patients on peripheral veno-arterial (VA) ECMO. The pathophysiologic mechanism
of ACS implicates a dramatic increase in compartmental pressures due to the
non-compliance of the surrounding osteofascial structures. Without sufficient time for
compensatory angiogenesis, the marked fluid extravasation and inflammation within the
rigid compartment persists. This increase in pressure leads to compression of
neurovascular structures, causing or further perpetuating any pre-existing limb ischemia.
The underlying cause of the increased compartmental pressures may be due to a variety of
causes in these ECMO patients without a history of trauma, such as ischemia and
rhabdomyolysis due to direct disruption of arterial flow (i.e. arterial thromboembolism),
obstruction of venous flow (i.e. deep vein thrombosis), direct hemorrhage into the
compartment from coagulopathy, or reperfusion injury due to calcium overload and
microvascular dysfunction. The treatment of ACS is timely (less than 6 hours from
diagnosis) fasciotomy, which is limb-saving.
In awake patients, ACS is a clinical diagnosis relying on medical history, visual
examination, palpation of pulses, and symptoms of pallor, paresthesia, out-of-proportion
pain with passive stretch, and paresis. Though more technically demanding perhaps,
duplex/doppler ultrasound may also be employed as an imaging technique to visualize blood
flow and characterize the extent of any obstruction underlying the ischemia. Since the
mainstay of diagnosis remains to be the subjective pain of the patient, the diagnosis of
ACS in ECMO patients is challenged by the fact that patients on ECMO are typically
intubated and receiving sedative medications. Thus, compartment pressure measurements >30
mmHg may be the only available diagnostic finding in addition to clinical suspicion based
on history and tense muscular compartments for diagnosing ACS.
Traditionally, the standard of care for measuring intracompartmental pressure has been
using a needle compartment pressure measuring device (Ex. Stryker needle). Some
institutions also use a continuous compartment pressure measuring device in the form of a
14-gauge slit catheter attached to a pressure transducer. The main drawback with
utilizing the needle compartment measuring device is that it only provides a single time
point recording and is difficult to employ for repetitive use. While using the 14-gauge
catheter and transducer offers continuous monitoring, this method creates an additional
line to manage for patients on ECMO and runs the risk of failing due to clot formation,
especially in patients without anticoagulative measures. In summary, diagnosis of ACS in
ECMO patients is challenging, and clinicians currently lack a method for accurate,
reliable, and continuous measurement of intracompartmental pressure that is
well-tolerated.
Employing digital micro sensing technology, the MY01 Continuous Compartmental Pressure
Monitor (NXTSens Inc., Montreal, Canada) is a high-precision, implantable device that can
continuously measure intracompartmental pressure. Having shown over 600% improved
accuracy when compared to standard compartment pressure measuring devices, this advanced
sensory microsystem can provide pressures with an accuracy of ±0.008 mmHg, which are then
relayed to a cloud storage database as well as the MY01 mobile application for easy
accessibility. With such reliable and real-time continuous pressure monitoring, MY01 may
be the optimal diagnostic tool for ACS in patients on ECMO and lead to more prompt,
limb-saving surgical fasciotomies.
Therefore, the investigators hypothesize that the MY01 device in conjunction with current
standard of care will help identify which patients on VA-ECMO have ACS more precisely
than current standard of care alone, which includes physical exam findings and single
timepoint needle compartment measurement. Additionally, the investigators hypothesize
that the MY01 device will be less invasive and easier to use than previously described
methods of continuous compartment pressure monitoring utilizing a 14-gauge slit catheter.