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

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

Status: Completed

Conditions: Cerebrovascular Circulation

Treatments: Other: Mechanical ventilation; Drug: Sevoflurane; Drug: Phenylephrine infusion; Drug: Propofol

Study type: Interventional

Funder types: Other

Identifiers

NCT03816072

METC 2018_230

Details and patient eligibility

About

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.

Enrollment: 66 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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.

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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66 participants in 2 patient groups

Propofol

Active Comparator group

Description:

ASA-I/II patients undergoing elective, non-cardiothoracic surgery with intravenous anaesthesia (propofol).

Treatment:

Drug: Phenylephrine infusion

Drug: Propofol

Other: Mechanical ventilation

Sevoflurane

Active Comparator group

Description:

ASA-I/II patients undergoing elective, non-cardiothoracic surgery with inhalational anaesthesia (sevoflurane).

Treatment:

Drug: Sevoflurane

Drug: Phenylephrine infusion

Other: Mechanical ventilation