The aim of this multicentre, single-blinded, expertise-based randomised controlled trial is evaluate whether slowly increasing the dose of the anaesthetic drug propofol based on a patient's needs leads to more stable blood pressure compared to giving a standard starting dose in patients aged 55 and older undergoing non-cardiac surgery.
Propofol is a widely used anaesthetic drug known to lower blood pressure (hypotension) by relaxing blood vessels. The extent of hypotension depends on the dose and speed of propofol administration. A significant drop in blood pressure after anaesthesia is started, known as post-induction hypotension (PIH), can damage organs like the heart and kidneys, especially in older and multimorbid patients. Target-controlled infusion (TCI) systems are commonly used to deliver anaesthetic drugs like propofol and remifentanil in a controlled way. The standard approach for starting anaesthesia (induction) is to begin with a high dose to quickly make the patient unconscious and suppress the body's response to intubation. Titration is a potentially safer alternative, where the dose is slowly increased until the patient becomes unconscious. However, current evidence comparing the two methods is limited, especially in older patients. A small retrospective study suggested that titration improves blood pressure stability, and a survey of Swiss anaesthetists showed strong interest in this approach. This multicentre, single-blinded, expertise-based randomised controlled trial investigates whether titration using TCI systems improves blood pressure stability in patients aged 55 and older undergoing non-cardiac surgery. The results of this trial will help to evaluate the clinical applicability and economic impact of the titration method in routine anaesthesia care and may support its future implementation into standard practice.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
320
Induction starts with propofol target-controlled Infusion (TCI) (Schnider model) at target effect-site drug concentration (Cet) 0.5-1.0 µg/mL and remifentanil TCI (Minto model) at Cet 0.5 ng/mL. If loss of consciousness (LOC) is not reached, propofol Cet is increased in 0.5-1.0 µg/mL steps. For intubation, remifentanil Cet increases up to 6.0 ng/mL.
Induction starts with propofol TCI at Cet 4-8 µg/mL and remifentanil TCI at Cet 2.5-3.5 ng/mL.
Kantonsspital Baden
Baden, Switzerland
NOT_YET_RECRUITINGUniversity Hospital Basel
Basel, Switzerland
RECRUITINGCantonal Hospital Graubünden
Chur, Switzerland
NOT_YET_RECRUITINGArea under the mean arterial pressure threshold (AUT)
The area under the mean arterial pressure (MAP)-time curve below each patient's individual baseline MAP (AUT) is measured during the first 30 minutes after the start of anaesthesia induction.
Time frame: 30 min after start of induction
Maximum Deviance (maxDev)
The maximum deviation between baseline MAP and the lowest recorded MAP (maxDev) is measured during the first 30 minutes after the start of anaesthesia induction.
Time frame: 30 min after start of induction
Use of vasoactive drugs
The administration of vasoactive drugs during the first 30 minutes following the start of anaesthesia induction is documented.
Time frame: Up to 30 min after start of induction
Use of Trendelenburg/ lithotomy positioning
The application of Trendelenburg/lithotomy positioning, where the patient is laid flat with the legs elevated above the head during the first 30 minutes following the start of anaesthesia induction is documented. If applied, the duration of this positioning is recorded.
Time frame: Up to 30 min after start of induction
Total propofol consumption
Total propofol consumption in mg/kg is assessed at loss of consciousness (LOC), during the first 30 minutes after the start of anaesthesia induction, and at skin incision.
Time frame: At LOC, up to 30 min after start of induction, and at skin incision
Neurocognitive test
To assess changes in neurocognitive performance, the validated, computerised Creyos task battery is used. Changes from baseline are used to evaluate the short-term impact of anaesthesia induction method on postoperative cognition.
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Kantonsspital Olten, soH
Olten, Switzerland
Time frame: before surgery, 1 and 3-5 hours after recovery of consciousness (ROC)
Brice Interview
To evaluate the occurrence of intraoperative awareness, the the structured and validated Brice interview is conducted postoperatively.
Time frame: 3-5 hours after ROC
Time from induction start to LOC
The time from the start of anaesthesia induction to the onset of LOC is measured. LOC is defined by the absence of response to verbal and tactile stimuli, loss of the eyelash reflex, and no reaction to a jaw thrust manoeuvre. The time to LOC will be recorded to assess the speed of induction between different anaesthesia techniques.
Time frame: From induction start to LOC
Total remifentanil consumption
Total remifentanil consumption in ug/kg is assessed at LOC, during the first 30 minutes after the start of anaesthesia induction, and at skin incision.
Time frame: At LOC, up to 30 min after start of induction, and at skin incision
Time from induction start to intubation
The time from the start of anaesthesia induction to successful intubation is measured.
Time frame: From induction start to intubation
Signs of reaction to intubation
The occurrence of signs of reaction to intubation are recorded as yes/no. If a reaction is noted, the specific signs will be documented in free text, including but not limited to tachycardia, cough reflex, limb movement, or eye opening. This outcome will help evaluate the anaesthesia technique's ability to suppress intubation responses.
Time frame: During intubation
Effect-site concentration of propofol
The effect-site concentration (Ce) of propofol is measured at LOC and ROC.
Time frame: At LOC and ROC
Effect-site concentration (Ce) of remifentanil
The effect-site concentration (Ce) of remifentanil is measured at LOC and ROC.
Time frame: At LOC and ROC
Duration of MAP below threshold
The time that the MAP remains below 70 mmHg and 60 mmHg during the first 30 minutes following the start of anaesthesia induction is recorded.
Time frame: Up to 30 min after start of induction
Bispectral Index at skin incision
The Bispectral Index (BIS) value at the time of skin incision as a measure of the patient's level of consciousness is recorded.
Time frame: At skin incision
Total opioid consumption
The total opioid consumption during the post-anaesthesia care unit (PACU) stay is recorded.
Time frame: During PACU stay