Closed Loop Isoflurane Administration With Bispectral Index in Open Heart Surgery - Full Text View

Purpose

With the advancement in microprocessor technology and better understanding of pharmacodynamics and pharmacokinetics of anaesthetic agents, computer facilitated closed loop control of anaesthesia using propofol has been shown to be accurate with better performance than manual control. Literature on computer controlled administration of inhalational anaesthetics is few, as it requires the computer to control the dial setting on the vapouriser. The investigators intend to compare the computer controlled closed loop administration of isoflurane by infusing it into the anaesthetic circuit with conventional vaporiser control in elective open heart surgery.

40 patients (ASA (American Society of Anesthesiology) class II-IV; 18- 65 years) undergoing elective cardiac surgery requiring cardiopulmonary bypass (CPB) will be randomly divided into manual or closed loop groups. Propofol will be used for induction of anaesthesia in both groups followed by isoflurane for maintenance. In the manual group, isoflurane will be administered through the Tech 7 vapouriser during pre and post CPB periods to target bispectral index (BIS) of 50. In closed loop group, isoflurane will be administered using infusion of liquid isoflurane into expiratory limb of the closed circuit. This rate of infusion though a conventional syringe pump will be controlled by algorithm termed 'Improvised Anaesthetic Agent Delivery System' (IAADS) to maintain BIS of 50. Patients in both groups will receive 500ml of 100 % oxygen as fresh gas flow. The % of time bispectral index (BIS) is within the 10 of set target BIS of 50 will be the primary outcome measure. The secondary outcome measures will be median performance error (MDPE)(2), median absolute performance error (MDAPE)(2), wobble(2), divergence(2), amount of isoflurane used and hemodynamic parameters will be secondary outcome measures.

Condition	Intervention
Open Heart Surgery	Other: Conventional control Other: Closed loop control

Study Type:	Interventional
Study Design:	Allocation: Randomized Endpoint Classification: Safety/Efficacy Study Intervention Model: Parallel Assignment Masking: Single Blind (Subject)
Official Title:	Comparison of Isoflurane Anaesthesia by Closed Loop Controlled Administration Versus Manually Controlled Administration Using Bispectral Index in Open Heart Surgery

Resource links provided by NLM:

MedlinePlus related topics: Heart Surgery

Drug Information available for: Isoflurane

U.S. FDA Resources

Further study details as provided by Postgraduate Institute of Medical Education and Research:

Primary Outcome Measures:

Percentage of Time Bispectral Index Remains Within 10 of Target BIS of 50 [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
The duration of time depth of anesthesia was maintained in the recommended range (as measured by BIS) during the period isoflurane (general anesthetic) was administered to the study population. This value expressed as percentage is the primary outcome. BIS is an objective measure of depth of anesthesia derived from statistical(bispectral) analysis of electroencephalographic waves. BIS ranges from 0 to 100. It decreases monotonically from 100 in the awake state to lower values with sedation and anesthesia.

Secondary Outcome Measures:

Median Performance Error (MDPE) [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
The difference between the observed and target of measure of depth of anesthesia (BIS) expressed as percentage of target BIS is calculated as performance error every 30 seconds. This value may be either '+' or '_' indicating whether the observed measure is above the target (overshoot-+) or below the target (undershoot-_). The median value of all performance errors during isoflurane anesthesia is median performance error and is a measure of bias of the system. This outcome is expressed as the mean of Median Performance Errors per participant.
Median Absolute Performance Error (MDAPE) [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
The median of the absolute values of performance errors (without considering the direction of error) is median absolute performance error. This outcome measures the magnitude of error or inaccuracy of the system studied. A lower value indicates a more precise system.This outcome is expressed as the mean of Median Absolute Performance Errors per participant.
Wobble [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
Wobble measures the intra-individual variability in performance error.The median of the difference between individual performance errors throughout anesthesia and the median performance error for each participant is the wobble of that participant. The mean value per participant is indicated in the outcome measure.
Percentage of Time Heart Rate Remained Within 25% of Pre-op Baseline [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: Yes ]
The duration of time heart rate remained within 25% of the pre-operative baseline value during the period isoflurane (general anesthetic) was administered to the study population. This value is expressed as a percentage. This outcome is expressed as the mean of percentage of time per participant.
Percentage of Time Mean Arterial Pressure Remained Within 25% of Pre-op Baseline [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: Yes ]
The duration of time mean arterial pressure remained within 25% of the pre-operative baseline value during the period isoflurane (general anesthetic) was administered to the study population. This value is expressed as percentage. This outcome is expressed as the mean of percentage of time per participant
Intra-operative Awareness [ Time Frame: 3 days (approximately) ] [ Designated as safety issue: Yes ]
The number of patients who were able to recall the intra-operative events when assessed postoperatively. This was assessed by a structured protocol
Fentanyl Used [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
The total amount of fentanyl that was used during the procedure.
Intra Operative Adrenaline Used [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
The amount of adrenaline used during the procedure
INTRA OPERATIVE PHENYLEPHRINE USED [ Time Frame: 8 hours (approximately) ] [ Designated as safety issue: No ]
The amount of phenylephrine used during the procedure.

Enrollment:	40
Study Start Date:	January 2009
Study Completion Date:	June 2010
Primary Completion Date:	June 2010 (Final data collection date for primary outcome measure)

Arms	Assigned Interventions
Active Comparator: MANUAL In the manual group isoflurane was administered using Tech 7 vapouriser. The dial setting was controlled by the anesthesiologist to achieve and maintain a BIS of 50 during anesthesia.	Other: Conventional control The isoflurane administration to deliver anesthesia will be done conventionally through a Tec 7 vaporiser to maintain the bispectral index at 50. Other Name: MANUAL CONTROL
Experimental: IAADS group In this group, liquid isoflurane was injected into the circuit using a syringe pump controlled by the IAADS system.The IAADS system has the algorithm to regulate the rate of infusion of isoflurane such that BIS is achieved and maintained at 50 during anesthesia.	Other: Closed loop control The isoflurane administration to maintain anesthesia will be by infusion to the anesthesia circuit using syringe pump (injection technique). The rate of delivery of isoflurane will be regulated by computer that uses a control algorithm. Other Name: AUTOMATED CONTROL

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Eligibility

Ages Eligible for Study:	18 Years to 65 Years
Genders Eligible for Study:	Both
Accepts Healthy Volunteers:	No

Criteria

Inclusion Criteria:

American Society of Anesthesiology physical status 2- 4
elective open heart surgery under general anaesthesia
requiring Cardio Pulmonary Bypass (CPB)

Exclusion Criteria:

body weight ±30% of the ideal body weight
neurological disorder
use of any psychoactive medication
severe stenotic valve lesions
severe pulmonary artery hypertension
Tetrology of Fallot repair and other cyanotic heart diseases.

Contacts and Locations

Please refer to this study by its ClinicalTrials.gov identifier: NCT01069562

Locations

India
Post graduate institute of medical education and research
Chandigarh, India, 160012

Sponsors and Collaborators

Postgraduate Institute of Medical Education and Research

Investigators

Principal Investigator:	Puri GD, MBBS MD PhD	Post graduate institute of medical education and research
Principal Investigator:	Sethu Madhavan, MBBS	Post graduate institute of medical education and research
Principal Investigator:	Preethy J Mathew, MBBS, MD	Postgraduate Institute of Medical Education and Research

More Information

Publications:

Locher S, Stadler KS, Boehlen T, Bouillon T, Leibundgut D, Schumacher PM, Wymann R, Zbinden AM. A new closed-loop control system for isoflurane using bispectral index outperforms manual control. Anesthesiology. 2004 Sep;101(3):591-602.

Varvel JR, Donoho DL, Shafer SL. Measuring the predictive performance of computer-controlled infusion pumps. J Pharmacokinet Biopharm. 1992 Feb;20(1):63-94.

Agarwal J, Puri GD, Mathew PJ. Comparison of closed loop vs. manual administration of propofol using the Bispectral index in cardiac surgery. Acta Anaesthesiol Scand. 2009 Mar;53(3):390-7.

Puri GD, Kumar B, Aveek J. Closed-loop anaesthesia delivery system (CLADS) using bispectral index: a performance assessment study. Anaesth Intensive Care. 2007 Jun;35(3):357-62.

Responsible Party:	Prof G. D. Puri, Post Graduate Institute of Medical Education and Research
ClinicalTrials.gov Identifier:	NCT01069562 History of Changes
Other Study ID Numbers:	closed loop isoflurane
Study First Received:	February 1, 2010
Results First Received:	August 2, 2010
Last Updated:	January 24, 2011
Health Authority:	India: Institutional Review Board

Keywords provided by Postgraduate Institute of Medical Education and Research:

closed loop control of anesthesia
isoflurane
open heart surgery

Additional relevant MeSH terms:

Anesthetics
Isoflurane
Central Nervous System Depressants
Physiological Effects of Drugs
Pharmacologic Actions

Central Nervous System Agents
Therapeutic Uses
Anesthetics, Inhalation
Anesthetics, General

ClinicalTrials.gov processed this record on June 18, 2013