Background and Purpose:
In the subarachnoid hemorrhage (SAH) patient intravascular volume status is one of three important components in the treatment of cerebral vasospasm. Traditionally, pulmonary artery occlusion pressure (PAOP) coupled with central venous pressure (CVP) were values obtained to help determine the intra-vascular volume status in these patients and were used to help guide the treatment of cerebral vasospasm. However, pulmonary artery (PA) catheter derived values are unreliable, and have poor sensitivity and specificity. The use of minimally invasive hemodynamic monitoring via an arterial line has been shown to be more reliable than the PA catheter in determining the state of a patient’s fluid volume status. The goal is to demonstrate that minimally invasive hemodynamic monitoring is a more reliable source of data and therefore a better guide for the treatment of cerebral vasospasm compared to the PA catheter.
Methods:
Our institution’s method of utilizing the minimally invasive hemodynamic monitoring device to aide in determining a patient’s fluid volume status and consequently treating cerebral vasospasm is unconventional from its originally intended use. It was through trial, error, and extensive research that our institution implemented and developed a protocol, therefore eventually replacing the PA catheter. The desired data to be collected is stroke volume variation (SVV) and stroke volume index (SVI). This data is also coupled with CVP obtained via a central venous catheter (CVC). The protocol states that if two out of three of the SVV, SVI, or CVP values are out of desired range, then a fluid bolus should be given. These numbers are adjusted as needed to correlate with both the clinical and pulmonary status of the patient.
Results:
As a result of the initiation of this protocol, coupled with the other two pieces of “Triple H” therapy, there has seemingly been a less incidence of both vasospasm and pulmonary edema compared to the utilization of the PA catheter.
Conclusions:
In conclusion, given that there are no formal studies comparing minimally invasive hemodynamic monitoring directly to the PA catheter in the same patient, formal studies need to be conducted in order to obtain data to confirm observations noted in our institution.
Invasive, minimally invasive and non-invasive hemodynamic monitoring in perioperative medicine
