None listed
Conditions
Brief summary
During Personalised External Aortic Root Support (PEARS) surgery, blood pressure is deliberately lowered for a prolonged period to allow safe placement of the external aortic support. This study will investigate how the brain regulates its blood flow during these periods of low blood pressure using non-invasive monitoring techniques. Researchers will determine whether each patient has an individual blood pressure threshold below which blood flow regulation becomes impaired. The study will examine whether time spent below this threshold is associated with postoperative complications, including delirium, kidney injury, heart injury, and changes on brain imaging. The findings will help determine whether personalised blood pressure targets may improve patient outcomes during future surgery.
Interventions
Participants undergoing elective Personalised External Aortic Root Support (PEARS) surgery will provide written informed consent for prospective observational collection of perioperative physiological data, clinical outcome data, blood samples, and follow-up assessments. The study will not alter routine clinical management and all participants will receive standard perioperative care.
Participants will undergo brief preoperative cognitive screening using the Telephone Interview for Cognitive St
Participants undergoing elective Personalised External Aortic Root Support (PEARS) surgery will provide written informed consent for prospective observational collection of perioperative physiological data, clinical outcome data, blood samples, and follow-up assessments. The study will not alter routine clinical management and all participants will receive standard perioperative care. Participants will undergo brief preoperative cognitive screening using the Telephone Interview for Cognitive Status (TICS), which takes approximately 5–10 minutes. During surgery, routine invasive arterial blood pressure monitoring, regional cerebral oxygen saturation (rSO2) using near-infrared spectroscopy (NIRS), processed electroencephalography using BIS, and routine physiological monitoring data will be recorded. Additional non-invasive research monitoring will include broadband NIRS to assess cytochrome c oxidase (oxCCO), and transcranial Doppler monitoring of cerebral blood flow velocity where feasible. These data will be analysed offline using wavelet semblance analysis to determine the lower limit of cerebral autoregulation (LLA) and quantify the duration and magnitude of mean arterial pressure below the LLA. Blood samples for study biomarkers will be collected at baseline, 24 hours, and 48 hours postoperatively, timed where possible to coincide with routine blood draws or obtained from clinically indicated vascular access. Delirium screening will be performed twice daily from postoperative day 0 to day 3 using CAM-ICU for intubated patients or UB-CAM for extubated patients. Participants may also choose to participate in an optional postoperative brain MRI sub-study, performed prior to discharge on postoperative day 5 ±2, subject to clinical stability and MRI safety requirements. Participants will be observed from enrolment before surgery until completion of postoperative follow-up, including in-hospital outcome assessment and day-30 postoperative cognitive assessment.
Sponsors
The University of Queensland
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Adults aged 18 years or older undergoing elective Personalised External Aortic Root Support (PEARS) surgery at The Prince Charles Hospital who are able and willing to provide informed consent and undergo general anaesthesia.
Exclusion criteria
Inability or unwillingness to provide informed consent; age under 18 years; not undergoing elective Personalised External Aortic Root Support (PEARS) surgery; contraindication to near-infrared spectroscopy monitoring (including dermatitis or allergy to adhesive dressings). Participants in the optional MRI sub-study will be excluded if they have contraindications to MRI.
Outcome results
None listed