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Completed

NCT Number: NCT03816072

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

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.

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Key information

Conditions

Cerebrovascular Circulation

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Amsterdam UMC, location AMC

Amsterdam, North Holland, 1105 AZ, Netherlands

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Phenylephrine infusion

Drug

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.

Mechanical ventilation

Other

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

Propofol

Drug

Propofol

Sevoflurane

Drug

Sevoflurane

Primary outcomes

  1. Changes in dCA after several MBP-increasing steps.

    Time frame: Intraoperatively

  2. Differences in dCA between sevoflurane and propofol at different steady-state MBP's.

    Time frame: Intraoperatively

Sponsors and collaborators

Lead sponsor

Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)

Other

Registry information

Official study title

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

Acronym: SAMBA

Important dates

Study start
2019
Primary completion
2019
Study completion
2019
First posted
Jan 25, 2019
Registry last updated
May 27, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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