Long-Term Measurements of Awake Blood Pressures Using Chronically Implanted Arterial Catheters
Without question, arterial pressures are most accurately measured via an indwelling catheter. For some studies, the presence of anesthesia or surgical recovery can have an impact on cardiac and vasoactive responses. To minimize the potential impact of such influences, arterial catheters can be introduced in the femoral artery and advanced into the abdominal aorta. The other end can be subcutaneously tunneled to exit at the nape of the neck. Later, the catheter can be connected to a pressure transducer to allow the measurement of arterial pressure in the awake animal.
This surgery is minimally invasive as animals are mobile, eating, drinking and voiding immediately upon recovery from anesthesia. Unlike corotid implants, these catheters can be maintained to permit precise inline arterial pressure measurements for at least one month (see above tracing).
While telemetry based probes are a viable alternative, such setups are expensive and the probes regularly require refurbishing. In addition the placement of such probes requires some expertise which demands a substantial window of training that is accompanied by failures. The use of chronically implanted femoral catheters requires less surgical experience, costs about $1 per catheter, and has a failure rate of less than 1 in 50.
Even so, the placement of such catheters impede the flow to one of the femoral arteries, and are reliant upon the reperfusion of the associated leg via the collateral circulation.