An interventional study of End-tidal-controlled sevoflurane wash-in and Low-flow high-concentration wash-in (0.5 L/min, 8% sevoflurane) in Anesthesia, General and Hypotension, sponsored by Ataturk University. Completed at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-10-26.
Sponsored by Ataturk University · Not applicable, Interventional, and Other
The goal of this clinical trial is to compare how four different ways of starting sevoflurane anaesthesia (the "wash-in" phase) affect the heart and circulation during the first 10 minutes after endotracheal intubation in adults undergoing elective major urological surgery. The main question it aims to answer is whether the wash-in strategy affects cardiac index 10 minutes after intubation. Researchers also compared other haemodynamic variables, the time needed to reach the target anaesthetic concentration (0.8 MAC), sevoflurane consumption, the need for ephedrine to treat low blood pressure, and depth of anaesthesia.
After a standard intravenous induction, participants were randomly assigned to one of four sevoflurane wash-in strategies: automated end-tidal-controlled delivery, or manual delivery with 0.5 L/min fresh gas flow and 8% sevoflurane, 1 L/min with 4% sevoflurane, or 2 L/min with 4% sevoflurane. Haemodynamic variables were measured continuously through a radial arterial line using the pressure recording analytical method (PRAM).
This prospective, randomised, single-centre, parallel-group trial was conducted in the Department of Anesthesiology and Reanimation, Atatürk University Faculty of Medicine (Erzurum, Türkiye). Adult ASA physical status I-II patients scheduled for elective major urological surgery were screened with a 45-degree passive leg-raising (PLR) test; patients with a mean arterial pressure (MAP) increase >10% received up to 600 mL saline in 200-mL boluses and were excluded if the response persisted. A radial arterial line was then placed, and eligible patients were allocated by the sealed-envelope method to one of four wash-in groups.
Anaesthesia was induced with propofol 2.5 mg/kg, fentanyl 1.5 mcg/kg and rocuronium 0.7 mg/kg, and the trachea was intubated when state entropy fell below 60. Sevoflurane was then delivered via an Aisys CS2 anaesthesia workstation (Datex-Ohmeda/GE HealthCare) according to the allocated strategy:
Haemodynamic variables (systolic, diastolic and mean arterial pressure, heart rate, cardiac index, stroke volume index, pulse pressure variation, cardiac cycle efficiency, maximum rate of arterial pressure rise [dP/dt], arterial elastance and cardiac power index) were obtained with the pressure recording analytical method (MostCare Up, Vygon) before induction (T0), 30 s after intubation (T1), when 0.8 MAC was reached (T2) and 10 min after intubation (T3). State entropy, wash-in duration, cumulative sevoflurane consumption and ephedrine use were recorded. Hypotension (MAP \<65 mmHg or a decrease >30% from baseline) was treated with 10 mg intravenous ephedrine.
The sample size (96 patients; 115 planned allowing for attrition) was calculated from pilot data for cardiac index at T3 (effect size f = 0.44, alpha 0.05, power 95%).
1,023 studies on the registry are indexed under Hypotension; 173 are open to participants now.
This study's enrollment of 102 is above the median of 80 across 688 interventional studies indexed under Hypotension.
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Exclusion Criteria:
Sevoflurane wash-in in automated end-tidal control mode targeting 0.8 MAC with a minimum fresh gas flow of 0.5 L/min.
Other: End-tidal-controlled sevoflurane wash-in
Low-flow, high-concentration (overpressure) sevoflurane wash-in with a fresh gas flow of 0.5 L/min and a vaporiser setting of 8% until 0.8 MAC is reached.
Other: Low-flow high-concentration wash-in (0.5 L/min, 8% sevoflurane)
Low-flow sevoflurane wash-in with a fresh gas flow of 1 L/min and a vaporiser setting of 4% until 0.8 MAC is reached.
Other: Low-flow wash-in (1 L/min, 4% sevoflurane)
Moderate-flow sevoflurane wash-in with a fresh gas flow of 2 L/min and a vaporiser setting of 4% until 0.8 MAC is reached.
Other: Moderate-flow wash-in (2 L/min, 4% sevoflurane)
After endotracheal intubation, sevoflurane is delivered with the Aisys CS2 workstation in automated end-tidal control mode targeting 0.8 MAC (age-adjusted, workstation-displayed), with a minimum fresh gas flow of 0.5 L/min.
After endotracheal intubation, sevoflurane wash-in is performed manually with a fresh gas flow of 0.5 L/min and a vaporiser setting of 8% until the workstation-displayed MAC reaches 0.8, after which maintenance is switched to end-tidal control targeting 0.8 MAC (minimum fresh gas flow 0.5 L/min).
After endotracheal intubation, sevoflurane wash-in is performed manually with a fresh gas flow of 1 L/min and a vaporiser setting of 4% until the workstation-displayed MAC reaches 0.8, after which maintenance is switched to end-tidal control targeting 0.8 MAC (minimum fresh gas flow 0.5 L/min).
After endotracheal intubation, sevoflurane wash-in is performed manually with a fresh gas flow of 2 L/min and a vaporiser setting of 4% until the workstation-displayed MAC reaches 0.8, after which maintenance is switched to end-tidal control targeting 0.8 MAC (minimum fresh gas flow 0.5 L/min).
Cardiac index
Cardiac index (L/min/m2) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line, compared between the four wash-in groups.
Time frame: 10 minutes after endotracheal intubation
Systolic arterial pressure
Systolic arterial pressure (mmHg) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Diastolic arterial pressure
Diastolic arterial pressure (mmHg) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Mean arterial pressure
Mean arterial pressure (mmHg) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Heart rate
Heart rate (beats/min) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Cardiac index at other time points
Cardiac index (L/min/m2) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1) and when 0.8 MAC is reached (T2)
Stroke volume index
Stroke volume index (mL/m2) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Pulse pressure variation
Pulse pressure variation (%) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded. Not assessed at T0 because patients were breathing spontaneously.
Time frame: 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Cardiac cycle efficiency
Cardiac cycle efficiency (unitless index, range -1 to +1) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Maximum rate of arterial pressure rise (dP/dt)
Maximum rate of rise of the radial arterial pressure, dP/dt (mmHg/ms) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Arterial elastance
Arterial elastance (mmHg/mL) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Cardiac power index
Cardiac power index (W/m2) measured with the pressure recording analytical method (PRAM; MostCare Up) via a radial arterial line. At each time point, the highest value among five consecutive beats was recorded.
Time frame: Before induction (T0), 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
Wash-in duration
Time (seconds) from the start of sevoflurane delivery after intubation until the age-adjusted MAC displayed by the anaesthesia workstation reaches 0.8.
Time frame: From start of sevoflurane delivery until 0.8 MAC is reached (up to 10 minutes after intubation)
Cumulative sevoflurane consumption
Cumulative liquid sevoflurane consumption (mL) as reported numerically by the anaesthesia workstation.
Time frame: When 0.8 MAC is reached and 10 minutes after intubation
Number of participants requiring ephedrine
Number of participants who received at least one 10-mg intravenous bolus of ephedrine for hypotension, defined as mean arterial pressure \<65 mmHg or a decrease \>30% from baseline.
Time frame: From induction of anaesthesia to 10 minutes after intubation
Time to first ephedrine administration
Time (seconds) from induction of anaesthesia to the first intravenous ephedrine bolus given for hypotension (mean arterial pressure \<65 mmHg or a decrease \>30% from baseline).
Time frame: From induction of anaesthesia to 10 minutes after intubation
State entropy
State entropy (units on a scale, 0-91) measured with the GE Entropy module; lower values indicate deeper hypnosis.
Time frame: 30 seconds after intubation (T1), when 0.8 MAC is reached (T2) and 10 minutes after intubation (T3)
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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