An observational study in Hypotension (MeSH: D007022), sponsored by Karolinska Institutet. Not yet recruiting. Open to participants aged 0 Years to 5 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Karolinska Institutet · Observational
Blood pressure is routinely monitored during anesthesia in children, but blood pressure alone may not accurately reflect blood flow to vital organs. This is particularly important in infants and young children, in whom normal cardiovascular values vary with age.
The CARFLOW study is a prospective observational study of 100 children aged 0-5 years undergoing anesthesia and surgery. The purpose is to investigate how blood flow in the common carotid artery, measured non-invasively using Doppler ultrasound, relates to blood pressure and cardiac output during anesthesia.
Carotid artery blood flow will be measured before and during anesthesia and compared with blood pressure recorded as part of routine monitoring. In children who are intubated, cardiac output will also be measured non-invasively using a capnodynamic method.
The main questions are whether changes in blood pressure are associated with changes in carotid artery blood flow, how carotid artery blood flow relates to cardiac output, and whether reference values for carotid artery blood flow during anesthesia can be established for young children.
All clinical decisions and treatment will follow routine clinical practice. Measurements performed as part of the study will not be used to guide treatment.
Blood pressure is routinely used as a surrogate for cardiovascular status during pediatric anesthesia. However, arterial blood pressure represents only one component of the circulation and may not directly reflect cardiac output or blood flow to individual organs. This is particularly relevant in infants and young children, in whom cardiovascular physiology and normal blood pressure values change substantially with age.
Blood flow in the common carotid artery can be assessed non-invasively using Doppler ultrasound. Because the carotid arteries contribute substantially to cerebral blood supply, measurement of carotid artery blood flow may provide additional information about changes in organ-directed blood flow during anesthesia. The CARFLOW study will investigate the relationship between Doppler ultrasound-derived common carotid artery blood flow, arterial blood pressure, and cardiac output in young children undergoing anesthesia and surgery.
Common carotid artery blood flow will be assessed using Doppler ultrasound, with the ultrasound probe positioned over the right common carotid artery just above the clavicle. Measurements will be obtained before induction of anesthesia, after induction and securing of the airway, and repeatedly during anesthesia. Additional measurements will be performed when blood pressure decreases below a predefined threshold and following clinically indicated treatment intended to increase blood pressure. Blood pressure monitoring and all decisions regarding treatment will remain part of routine clinical care.
In children managed with tracheal intubation, cardiac output will also be assessed using a non-invasive capnodynamic method based on controlled variations in carbon dioxide elimination during mechanical ventilation. This will allow simultaneous assessment of carotid artery blood flow, blood pressure, and cardiac output.
The study is intended to characterize how carotid artery blood flow varies during anesthesia in young children and how these changes relate to changes in blood pressure and cardiac output. The collected measurements will also provide data for describing carotid artery blood flow across the studied age range and may contribute to the development of reference values for carotid artery blood flow during pediatric anesthesia.
No treatment decisions will be based on the study-specific carotid blood flow or capnodynamic measurements. Anesthesia, hemodynamic management, and treatment of low blood pressure will be determined by the responsible clinical team according to routine clinical practice.
The study population will be recruited from children undergoing elective surgical procedures requiring general anesthesia at the Pediatric Operating Department, Karolinska University Hospital, Solna, Sweden. Participants will be identified among patients scheduled for routine clinical care at the study site.
Inclusion Criteria:Age 0-5 years Scheduled for elective surgery under general anesthesia at the Pediatric Operating Department, Karolinska University Hospital Written informed consent provided by parent or legal guardian -
Exclusion Criteria: Emergency surgery American Society of Anesthesiologists (ASA) physical status ≥3 Significant comorbidity Expected complicated anesthesia or surgical procedure Parent or legal guardian does not provide informed consent
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Children aged 0-5 years undergoing general anesthesia for elective surgery. Common carotid artery blood flow is measured non-invasively using Doppler ultrasound before and during anesthesia. Blood pressure is recorded as part of routine clinical monitoring. In children who are intubated, cardiac output is also assessed non-invasively using a capnodynamic method. Study-specific measurements do not guide clinical treatment.
Common Carotid Artery Blood Flow in Relation to Blood Pressure During Anesthesia
Common carotid artery blood flow will be measured in the right common carotid artery using Doppler ultrasound and analyzed in relation to simultaneously recorded blood pressure. Measurements will include observations before and after induction of anesthesia and repeated paired measurements during anesthesia, including measurements obtained when blood pressure falls below the predefined clinical threshold and after clinically indicated treatment to increase blood pressure.
Time frame: During anesthesia, up to 2 hours
Relationship between common carotid artery blood flow and blood pressure during anesthesia.
Common carotid artery blood flow will be measured non-invasively in the common carotid artery using Doppler ultrasound and compared with simultaneously recorded blood pressure. Measurements will be obtained before induction of anesthesia, after induction and securing of the airway, at 15-minute intervals during anesthesia, when blood pressure falls below the predefined clinical threshold, and approximately 3 minutes after clinically indicated treatment to increase blood pressure. The analysis will assess the relationship between carotid artery blood flow and blood pressure and whether low blood pressure is consistently associated with reduced carotid artery blood flow.
Time frame: From before induction of anesthesia until the end of anesthesia, up to 2 hours
Common Carotid Artery Blood Flow in Relation to Cardiac Output During Anesthesia
In children who are tracheally intubated, cardiac output will be measured non-invasively using the capnodynamic method. Common carotid artery blood flow measured using Doppler ultrasound will be analyzed in relation to simultaneously measured cardiac output.
Time frame: During anesthesia, up to 2 hours
No study locations are listed for this record.
Plan to share: No — Individual participant data are not planned to be made publicly available due to the pediatric study population and data protection considerations.
No publications or documents are linked to this record.
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Karolinska Institutet