Quantification of Dynamic and Static Cerebral Autoregulation (CA) Under Anaesthesia

Cerebrovascular Circulation Clinical Trial

— SAMBA  

Official title:

Simultaneous Quantification of Dynamic and Static Cerebral Autoregulation (CA) at Different Steady-state Mean Blood Pressures Under Anaesthesia.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03816072
• Other study ID #: METC 2018_230
• Status: Completed
• Phase: N/A
• Start date: January 7, 2019
• Est. completion date: September 23, 2019

Study information

• Verified date: May 2021
• Source: Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Cerebral autoregulation (CA) is the mechanism by which the brain vasculature maintains constancy of cerebral blood flow (CBF). Reliable direct measurements of CBF at different blood pressure levels are difficult because they are invasive and time-consuming. This type of measurement to quantify CA is generally referred to as static cerebral autoregulation (sCA). Alternatively, it is possible to measure CA indirectly from blood pressure oscillations. Dynamic cerebral autoregulation (dCA) measures how quickly the cerebral vessels react to a change in blood pressure to normalize CBF. Since the introduction of transcranial Doppler ultrasound (TCD), it has become possible to estimate CBF velocity relatively easy, which in turn correlates well with CBF changes. This method is widely used to quantify dCA. However, it is not clear how sCA correlates with dCA over a range of physiologic mean blood pressure (MBP). It is important to compare different methods of assessing CA, because impaired CA may result in increased risk of perioperative complications such as stroke. In this study, the investigators were interested in establishing the relationship between sCA and dCA during surgery under general anesthesia. The investigators aim to compare these methods during propofol and sevoflurane anesthesia.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 66
• Est. completion date: September 23, 2019
• Est. primary completion date: September 23, 2019
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• ASA-I or ASA-II, willing and able to give written informed consent, scheduled for elective, non-cardiothoracic surgery under general anaesthesia and age 18 years and above.

Exclusion Criteria:

• Patient related

• Unable/ unwilling to participate

• ASA-III or higher

• Age < 18 years

• History of: uncontrolled hypertension, diabetes, Parkinson's disease, uncontrolled cardiac arrhythmia, Pure autonomic failure (formerly called idiopathic orthostatic hypotension), Multiple system atrophy with autonomic failure (formerly called Shy-Drager syndrome), Addison's disease and hypopituitarism, pheochromocytoma, peripheral autonomic neuropathy (e.g., amyloid neuropathy, idiopathic autonomic neuropathy), known cardiomyopathy, extreme left ventricle hypertrophy or ejection fraction < 30%, proven or suspected allergy for any of the medication used during induction of anaesthesia, malignant hyperthermia.

• Unability to record transcranial Doppler ultrasound due to anatomical variance (~5% of population)

• Contra-indications for intravenous or inhalational anaesthesia.

• Contra-indications for phenylephrine: severe hypertension, peripheral vascular illness, severe hyperthyroidism

• Simultaneous use of MAO-inhibitors, dopaminergic or vasoconstrictor ergot alkaloids (bromocriptine, cabergoline, pergolide, ergotamine, methylergometrine, methysergide), linezolid, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, digoxin, quinidine, oxytocin.

• Surgery related

• Day case surgery

• Laparoscopy with CO2 insufflation

• Extreme positioning during surgery (head-down/up tilt, lateral decubitus position, prone)

• Surgery < 60 minutes.

Related Conditions & MeSH terms

• Cerebrovascular Circulation

Intervention

Drug:
• Phenylephrine infusion
Correction of anesthesia induced hypotension with phenylephrine to obtain sCA and dCA measurements at 60, 70, 80, 90 and 100 mmHg mean blood pressure. This is achieved by stepwise increases in phenylephrine infusion dose.

Other:
• Mechanical ventilation
Patientes are mechanically ventilated at 6 bpm to obtain low frequency blood pressure oscillations (~0.1 Hz).

Drug:
• Propofol
Propofol
• Sevoflurane
Sevoflurane

Locations

Country	Name	City	State
Netherlands	Amsterdam UMC, location AMC	Amsterdam	Noord-Holland

Sponsors (1)

Lead Sponsor	Collaborator
Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)

Country where clinical trial is conducted

Netherlands, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Changes in dCA after several MBP-increasing steps.		Intraoperatively
Primary	Differences in dCA between sevoflurane and propofol at different steady-state MBP's.		Intraoperatively