Blood Viscosity and Outcomes After Elective Craniotomy

Association of Intraoperative Blood Viscosity With Cerebral Oxygenation and Postoperative Composite Complications in Adults Undergoing Elective Intracranial Craniotomy: A Prospective Observational Study

This prospective observational study aims to evaluate the association between intraoperative blood viscosity and postoperative clinical outcomes in adult patients undergoing elective intracranial craniotomy.

Blood viscosity is an important determinant of microcirculatory flow and cerebral perfusion, but its role in perioperative outcomes remains unclear. In this study, intraoperative blood viscosity and related hematologic parameters will be measured, and their relationships with cerebral oxygenation and postoperative complications will be analyzed.

The study will enroll adult patients undergoing elective intracranial surgery at a single tertiary center. The findings of this study may improve understanding of perioperative hemodynamic and hemorheological factors and help identify potential risk markers for adverse postoperative outcomes.

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Complications; Intracranial Surgery
• Intervention / Treatment: Other: Observational Assessment of Blood Viscosity

• Study Type: Observational
• Enrollment (Estimated): 1000

Contacts and Locations

• Study Contact: Name: Ji-Hoon Sim, MD; Phone Number: +82-2-3010-0586; Email: jihoon_sim@amc.seoul.kr

Study Locations

• South Korea
  • Songpa
    • Seoul, Songpa, South Korea, 05505
      • Asan Medical Center
      • Contact: Ji-Hoon Sim, MD; Phone Number: +82-10-9237-2778; Email: jihoon_sim@amc.seoul.kr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult patients undergoing elective intracranial craniotomy at a single tertiary care center will be prospectively enrolled. All eligible patients will be consecutively included during the study period. The study population represents patients undergoing various types of intracranial surgery, including tumor resection and aneurysm clipping, managed according to standard clinical practice.

Description

Inclusion Criteria:

• Adults aged 18 to 80 years
• Patients scheduled to undergo elective intracranial craniotomy
• Patients requiring intraoperative arterial catheterization and routine arterial blood gas analysis
• Patients who provide written informed consent

Exclusion Criteria:

• Emergency surgery
• Patients in whom participation or follow-up is considered difficult by the investigator
• Patients unable to provide informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Elective Intracranial Craniotomy Patients; Adult patients undergoing elective intracranial craniotomy who are prospectively enrolled	Other: Observational Assessment of Blood Viscosity; No intervention is assigned. Intraoperative blood viscosity and clinical variables are measured as part of routine care and analyzed for association with postoperative outcomes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with one or more postoperative composite complications within 30 days after surgery	Composite complication is defined as the occurrence of at least one of the following within 30 days after surgery: postoperative neurologic complications, respiratory complications, cardiovascular complications, acute kidney injury defined as Kidney Disease Improving Global Outcomes stage 1 or higher, infectious complications requiring intravenous antibiotics or a procedure, reoperation or major postoperative intervention, or death.	Up to postoperative day 30

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in high-shear blood viscosity from after induction of anesthesia to near the end of surgery	High-shear blood viscosity will be measured at the first protocol-specified intraoperative blood sampling time point after induction of anesthesia and arterial line placement and at the second protocol-specified time point near the end of surgery. The reported value will be the change between the two measurements.	After induction of anesthesia and near the end of surgery
Change in low-shear blood viscosity from after induction of anesthesia to near the end of surgery	Low-shear blood viscosity will be measured at the first protocol-specified intraoperative blood sampling time point after induction of anesthesia and arterial line placement and at the second protocol-specified time point near the end of surgery. The reported value will be the change between the two measurements.	After induction of anesthesia and near the end of surgery
Change in TODI from after induction of anesthesia to near the end of surgery	TODI will be measured or calculated at the first protocol-specified intraoperative blood sampling time point after induction of anesthesia and arterial line placement and at the second protocol-specified time point near the end of surgery. The reported value will be the change between the two measurements.	After induction of anesthesia and near the end of surgery
Intraoperative regional cerebral oxygen saturation desaturation burden	Cumulative burden of intraoperative regional cerebral oxygen saturation below the predefined study threshold during surgery.	From after induction of anesthesia to end of surgery
Area under the predefined regional cerebral oxygen saturation desaturation threshold curve during surgery	Area under the predefined desaturation threshold curve for regional cerebral oxygen saturation during surgery	From after induction of anesthesia to end of surgery
Number of participants with postoperative neurologic complications within 30 days after surgery	Postoperative neurologic complications include new or worsened focal neurologic deficit, postoperative cerebral infarction, postoperative intracranial hemorrhage, clinically significant cerebral edema, seizure requiring treatment, or decreased consciousness or delayed emergence requiring imaging or additional intervention.	Up to postoperative day 30
Number of participants with postoperative respiratory complications within 30 days after surgery	Postoperative respiratory complications include pneumonia, reintubation, mechanical ventilation for more than 24 hours after surgery, pulmonary edema, or respiratory failure requiring treatment.	Up to postoperative day 30
Number of participants with postoperative cardiovascular complications within 30 days after surgery	Postoperative cardiovascular complications include myocardial infarction, new arrhythmia requiring treatment, or other clinically significant circulatory complications.	Up to postoperative day 30
Number of participants with acute kidney injury within 30 days after surgery	Acute kidney injury is defined as Kidney Disease Improving Global Outcomes stage 1 or higher within 30 days after surgery.	Up to postoperative day 30
Number of participants with postoperative infectious complications within 30 days after surgery	Postoperative infectious complications are defined as infections requiring intravenous antibiotics or a procedure within 30 days after surgery.	Up to postoperative day 30
Number of participants requiring reoperation or major postoperative intervention within 30 days after surgery	Reoperation or major postoperative intervention occurring within 30 days after surgery.	Up to postoperative day 30
Number of participants with all-cause mortality within 30 days after surgery	All-cause death occurring within 30 days after surgery.	Up to postoperative day 30

Collaborators and Investigators

• Sponsor: Asan Medical Center

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): December 31, 2029
• Study Completion (Estimated): March 31, 2030

Study Registration Dates

• First Submitted: March 31, 2026
• First Submitted That Met QC Criteria: April 7, 2026
• First Posted (Actual): April 15, 2026

Study Record Updates

• Last Update Posted (Actual): April 15, 2026
• Last Update Submitted That Met QC Criteria: April 7, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: hemodynamics; neurosurgery; cerebral oxygenation; postoperative complications; blood viscosity; intracranial craniotomy
• Additional Relevant MeSH Terms: Pathologic Processes; Pathological Conditions, Signs and Symptoms; Postoperative Complications
• Other Study ID Numbers: AMC (2026-0404)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No. Individual participant data will not be shared.