Continuous invasive arterial line monitoring is the most accurate way to monitor a
patient's hemodynamics. Being able to rapidly detect a spike or drop in blood pressure is
crucial in the care of both surgical and critically ill patients. Major fluctuations in
blood pressure have been associated with bleeding, cardiac damage, cognitive dysfunction,
stroke, and acute kidney injury. The impact of poor blood pressure control on patient
outcomes is influenced not only by how high or low the pressure gets, but how long it
remains at those extremes. The alternative to continuous blood pressure monitoring is to
use intermittent non-invasive blood pressure cuffs, which typically display a blood
pressure measurement every 5 minutes when being used in the operating room. While this
might be sufficient for routine, short surgeries and monitoring in stable patients, blood
pressure cuffs are inadequate for patients who are unstable or undergoing extensive
surgery.
An arterial line monitor involves the insertion of a catheter into the radial artery and
allows for the beat by-beat monitoring of blood pressure. The insertion of this monitor
is painful, time consuming, and puts the patient at risk of infection, bleeding, nerve
injury, and damage to the artery. There are many factors that can complicate the
insertion of the arterial line including the presence of peripheral vascular disease,
small arteries, large body habitus, and poor patient cooperation. In view of these
problems, researchers have investigated non-invasive monitoring systems as alternatives
to invasive arterial cannulation, but these data are limited and inconsistent.
A alternative device called the ClearSight monitor, produced by Edwards LifeSciences,
provides continuous noninvasive blood pressure monitoring. The ClearSight monitor
connects to the patient by wrapping an inflatable cuff around their finger. It will
detect the blood volume fluctuations in the finger that occur with each heartbeat. It
then converts that volume change data into beat-by-beat hemodynamic information,
including blood pressure, mean arterial pressure, cardiac output, stroke volume and
stroke volume variation. The ClearSight monitor was developed to advance hemodynamic
monitoring of moderate-to high-risk surgery patients, including elderly and obese
patients.
Patients receiving elective cardiac or cerebrovascular disease are an ideal population to
study. These patients require continuous blood pressure monitoring to prevent radical
swings in blood pressure (either high or low), which can put the patient at risk of
intracranial hemorrhage and increased intracranial pressure, or tissue ischemia,
respectively. In addition, these patients frequently have many comorbid conditions
including coronary artery disease, congestive heart failure, peripheral vascular disease,
cerebrovascular disease, dementia, chronic obstructive pulmonary disease, hypertension,
liver disease, renal disease, obesity, malignancy, and diabetes. Many of these health
conditions may compromise and affect ClearSight system's ability to analyze blood
pressure. For example, peripheral vascular disease, diabetes, and hypertension can cause
arterial damage, arterial stenosis and reduced blood flow to the hands and feet.
Consequently, it will be informative to test the ClearSight's accuracy in this medically
challenging patient demographic.
The current standard of care for patients coming for elective cardiac or
neurointerventional procedures at Royal University Hospital is an invasive arterial
cannulation. The purpose of this study is to compare the systolic blood pressure,
diastolic blood pressure, and mean arterial blood pressure measured by the non-invasive
blood pressure monitor (ClearSight) versus the invasive radial arterial cannulation in
these patients.