Transfer Function Analysis of Cerebral Blood Pressure-flow Relationships Following Aneurysmal Subarachnoid Hemorrhage and Delayed Cerebral Ischemia: A Pilot Observational Single Cohort Study

Study ID
STU 082012-016

Cancer Related
No

Healthy Volunteers
No

Study Sites

  • UT Southwestern University Hospital– Zale Lipshy

Contact
Emine Babar Melik
214-590-8081
emine.barbarmelik@utsouthwestern.edu

Principal Investigator
Kevin Gingrich

Summary

Subarachnoid hemorrhage (SAH) following the rupture of an intracranial aneurysm frequently later leads to brain ischemia termed delayed cerebral ischemia (DCI). DCI is a devastating complication that may culminate in brain infarction with associated debilitating morbidity, and even mortality. The time window of DCI susceptibility is wide and begins as early as days following SAH and persists for weeks thereafter. A serial, sensitive, bedside predictor of early progression to DCI would reduce the time to definitive diagnosis and aggressive therapy, but one does not currently exist. Cerebral blood pressure-flow relationships are altered in DCI. However a deep understanding of the underlying pathophysiologic changes is lacking. Transfer function analysis of cerebral blood pressure-flow relationships provides deep insight into regulation of cerebral hemodynamics, but it is yet to be applied to CDI. Furthermore, this analysis can be obtained serially at the bedside utilizing physiological variables that are routinely collected in these patients.

This study is a pilot, prospective, observational, single cohort study of patients who have suffered subarachnoid hemorrhage (SAH) following intracranial aneurysm rupture in which transfer function analysis of cerebral-pressure flow relationships will be serially characterized.

Inclusion Criteria:(1) Age 18 - 75, all races/ethnicities, and both genders are eligible: (2)Subjects that meet the criteria for SAH related to the rupture of intracranial aneurysm; (3)Availability of arterial blood pressure (ABP), transcranial Doppler cerebral blood flow velocity (CBFv) of middle cerebral and internal carotid arteries, EKG, and expired CO2.
Exclusion Criteria none.

All variables will be collected as they are available for each patient. At a minimum, arterial blood pressure (ABP), transcranial Doppler cerebral blood flow velocity (TCD) of middle cerebral and internal carotid arteries, EKG, and expired CO2 are required for study inclusion. If the patient is spontaneously breathing without an endotracheal tube, then nasal prongs will be placed near the nose to collect continuous expired CO2. ABP will be obtained from an intra-arterial catheter. Other variables that will be recorded if available are intracranial pressure (ICP), and central venous pressure (CVP). All available analog signals will be sampled simultaneously at 100Hz and digitized at 12 bits. Variables will be collected for a total of about 5 minutes each for middle cerebral and internal carotid arteries.
This in an observational study and no therapies or interventions will be made based on the data collected. The study will increase the duration of TCD data collection by approximately 15 minutes. TCD data collection periods range from 60-90 minutes during routine care of these patients.

Participant Eligibility

Inclusion Criteria:
1. Age 18 – 75, all races/ethnicities, and both genders are eligible.
2. Subjects that meet the criteria for SAH related to the rupture of intracranial aneurysm
3. Availability of arterial blood pressure (ABP), transcranial Doppler cerebral blood flow velocity (CBFv) of middle cerebral and internal carotid arteries, EKG, and expired CO2.