Clinical trial NCT02515019: Bispectral Index Guided Sevoflurane Titration
Official title: Bispectral Index Guided Titration of Sevoflurane in On-pump Cardiac Surgery Reduces Plasma Sevoflurane Concentration and Vasopressor Requirements
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Intraoperative Hypotension
Keywords: Anaesthetics inhalation
Bispectral index
Cardiopulmonary bypass
Lead sponsor: Universitätsklinikum Hamburg-Eppendorf
Sponsor class: OTHER
First posted: 2015-08-04
Enrollment: 60
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: Electroencephalographic-based monitoring systems such as the bispectral index (BIS) may reduce anaesthetic overdose rates. The investigators hypothesised that goal-directed sevoflurane administration (guided by BIS monitoring) could reduce the sevoflurane plasma concentration (SPC) and intraoperative vasopressor doses during on-pump cardiac surgery in a prospective, controlled, sequential two-arm clinical study.

Detailed description: Electroencephalographic (EEG)-based monitoring systems, for example the bispectral index \[(BIS); BIS monitor, Covidien, Boulder, Colorado, USA\], were designed to prevent anaesthesia underdosage with the risk of awareness and to reduce the time to awakening after terminating general anaesthesia. However, little is known about the consequences of anaesthetic overdose. The investigators assume that high doses of anaesthetics result in cardiocirculatory depression and the necessity for high-dose vasopressor therapy, followed by microcirculation disorder and organ dysfunction.

The investigators hypothesised that in on-pump cardiac-surgery, goaldirected administration of sevoflurane guided by BIS monitoring reduces excessive sevoflurane plasma concentration (SPC) and the need for an intraoperative vasopressor. To test this hypothesis, the current study compared BIS-guided sevoflurane administration with the constant delivery of an inspired sevoflurane concentration of 1.8% during on-pump cardiac surgery and analysed its effect on the SPC and the required intraoperative dosage of norepinephrine.

The study population was divided into two patient groups: Thirty-three on-pump cardiac surgery patients enrolled in the study were allocated to a conventionally treated control group, with the constant administration of an inspired concentration of sevoflurane 1.8% (group Sevo1.8%). Thirty-four patients were sequentially allocated to an interventional group with BIS-guided administration of sevoflurane (group SevoBIS).

Vasoactive drugs were administered according to the following protocol in both groups. If the mean arterial blood pressure decreased below 50 mmHg, a continuous infusion of norepinephrine was given to maintain a perfusion pressure between 50 and 60 mmHg during cardiopulmonary bypass. If the mean arterial pressure increased above 75 mmHg, nitroglycerine was used in boluses of 0.1 mg until arterial pressure returned to a mean of less than 75 mmHg. If mean arterial pressure persisted above 75 mmHg after a cumulative administration of nitroglycerine 1.0 mg, urapidil was administered in boluses of 0.1 mg/kg until the perfusion pressure decreased below 75 mmHg.

At the end of the surgical procedure, all patients were transferred to the ICU.

Eligibility criteria: Inclusion Criteria:

* Undergoing elective on-pump cardiac surgery and an American Society of Anesthesiologists' (ASA) physical status of 3 to 4

Exclusion Criteria:

* A contraindication to the administration of volatile anaesthetics, an active infection with a temperature more than 38°C and any history of neurological disease

Primary outcomes:
measure: Cumulative intraoperative administration of norepinephrine
timeFrame: During operation
Secondary outcomes:
measure: Sevoflurane concentration in the oxygenator freshgas supply during cardiopulmonary bypass
timeFrame: During operation
measure: Postoperative blood lactate concentration
timeFrame: Upon arrival in the intensive care unit (ICU)
measure: Duration of postoperative mechanical ventilation
timeFrame: Participants will be followed for the duration of hospital stay, an expected average of 2 weeks
measure: ICU length of stay
timeFrame: Participants will be followed for the duration of hospital stay, an expected average of 2 weeks
measure: Incidence of acute kidney injury
timeFrame: Participants will be followed for the duration of hospital stay, an expected average of 2 weeks
measure: Sevoflurane Plasma Concentration during CPB
timeFrame: During operation
Other outcomes:
Locations:
city: Hamburg
country: Germany
facility: Department of Anesthesiology; Center of Anesthesiology and Intensive Care Medicine, Hamburg Eppendorf University Medical Center
Study officials:
affiliation: Department of Anesthesiology; Center of Anesthesiology and Intensive Care Medicine, Hamburg Eppendorf University Medical Center
name: Christian Zoellner, Professor
role: STUDY_CHAIR
References: