Assessment of Cerebral Blood Flow Asymmetry in Cardiac Surgery Patients Undergoing Hypothermic Circulatory Arrest

University of Manitoba8 enrolled

Overview

Cerebral oxygen desaturation during cardiac surgery measured using near infrared spectroscopy (NIRS) derived cerebral oximetry has been associated with significant postoperative morbidity. If significant desaturation occurs during this period, it may represent an ideal opportunity to further optimize the postoperative care of these patients.

Selective antegrade cerebral perfusion (SACP) is a commonly used technique for maintaining cerebral blood flow (CBF) during the use of hypothermic cardiac arrest (HCA) for aortic arch reconstruction. However, even with an intact Circle of Willis, asymmetric CBF is a common occurrence during HCA when SACP is used. The investigators have previously shown that ultrasound guided extrinsic compression of the left carotid artery can increase left cerebral oxygen saturation, and improved symmetry of CBF; however, this has not been investigated formally. In this study, the investigators will firstly formally assess the incidence and severity of asymmetrical cerebral flow between the left and right hemispheres in patients undergoing aortic arch repair (n=20). CBF will be assessed indirectly through regional cerebral oxygen saturation (rSO2) measured via near-infrared spectroscopy-derived cerebral oximetry. In addition, a number of clinical outcome parameters (up to 30 days post-op) will be evaluated. The investigators expect that significant left-side cerebral hypoperfusion will consistently be observed in patients undergoing aortic arch repair using SACP.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Cerebral Desaturation Cerebral Ischemia

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Informed consent * Age 18 years or older * Surgery requiring cardio pulmonary bypass * Ascending aorta or arch repair surgery * Surgery requiring hypothermic circulatory arrest Exclusion Criteria: * Off-pump cardiac surgery * Skin condition preventing the use of cerebral oximetry pads

Locations (1)

St. Boniface Hospital

Winnipeg, Manitoba, Canada

Outcomes

Primary Outcomes

Incidence of asymmetrical cerebral desaturation

Cerebral desaturation defined as a greater than 10% difference in cerebral saturation comparing one hemisphere to the other based on a baseline reading taken in the minute preceding the onset of HCA to the end of the hypothermic period.

Time frame: Duration of hypothermic circulatory arrest between surgical induction and ICU admission

Secondary Outcomes

Severity of asymmetrical cerebral desaturation

Area of the curve (AUC) and time under the curve (TUC) for all saturation events less than pre-induction baseline as well as for 10%, 15% and 25%, relative reductions under the baseline rSO2 will also be determined. In addition, the AUC and TUC for rSO2 less than an absolute rSO2 of 50% will also be determined.

Time frame: Duration of hypothermic circulatory arrest between surgical induction and ICU admission

Severity of asymmetrical cerebral desaturation

Time under the curve (TUC) for all saturation events less than pre-induction baseline as well as for 10%, 15% and 25%, relative reductions under the baseline rSO2 will also be determined. In addition, the AUC and TUC for rSO2 less than an absolute rSO2 of 50% will also be determined.

Time frame: Duration of hypothermic circulatory arrest between surgical induction and ICU admission

All cause mortality

Time frame: Surgical induction to 30 day postoperative

Neurologic injury

Any neurologic injury, including: stroke, delirium, seizures, coma

Time frame: Surgical induction to 30 day postoperative

Renal injury

Renal injury defined as a 50% decrease in estimated glomerular filtration rate (GFR) and/or need for dialysis

Data from ClinicalTrials.gov

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