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NCT Number: NCT01962285

Neuronal Inertia in Propofol Anesthesia

Loss and recovery of consciousness during propofol anesthesia seem to be mediated by different mechanisms beyond the actual effect-site concentration of anesthetic drug. This eventual difference between dose response curves for loss of consciousness (LOC) and for recovery of consciousness (ROC) beyond hysteresis has received the name of neuronal inertia. We performed a volunteer-study comparing LOC and ROC curves during a slow, steady-sate, stepped target controlled infusion of Propofol. Our hypothesis is that, at steady-state conditions between plasma an effect-site concentration, there is still going to exist a difference between LOC and ROC, demonstrating the existence of neuronal inertia.

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Key information

Conditions

General Anesthesia Consciousness Disorders Loss of Consciousness and Recovery of Consciousness Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Propofol Pharmacodynamics Propofol Plasma Concentration Propofol Target Controlled Infusion Signs and Symptoms Unconsciousness

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Clinica Alemana de Santiago

Santiago, Santiago Metropolitan, Chile

About this study

Loss and recovery of consciousness during propofol anesthesia seem to be mediated by different mechanisms beyond the actual effect-site concentration of anesthetic drug. This eventual difference between dose response curves for loss of consciousness (LOC) and for recovery of consciousness (ROC) beyond hysteresis has received the name of neuronal inertia. We performed a volunteer-study comparing LOC and ROC curves, during a slow, steady-sate, stepped target controlled infusion of Propofol using Schnider's pharmacologic model. Our hypothesis is that, at steady-state conditions between plasma an effect-site concentration, there is still going to exist a difference between LOC and ROC, demonstrating the existence of neuronal inertia.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • american society of anesthesiologists status I or II age >18 years fasted at least 8 hours BMI<30

Exclusion criteria

  • any known adverse reaction to propofol administration soy or egg-protein allergy psychotropic use (illegal of medically indicated)

Treatment and study plan

propofol targel controlled infusion

Drug

slow stepped propofol target controlled infusion using Schinider´s pharmacokinetic parameters seriated venous blood sampling

Other names: propofol TCI

Primary outcomes

  1. plasma-equilibrated effect site concentration of propofol at LOC and ROC (mcg/ml)

    Time frame: 2 hours (during slow steady-state concentration propofol infusion)

    determination of plasma concentration of PROPOFOL at the time of Loss of Consciousness and the time of recovery of consciousness during the 7-minute step infusion.

    Provided it is a slow increasing infusion we assume a pseudo-equilibrium state between plasma and effect site.

    the existence of a difference between these two values will support the hypothesis of neuronal inertia

Secondary outcomes

  1. Bispectral Index (BIS) al LOC and ROC

    Time frame: 2 hours (during slow increasing TCI (Target controlled Infusion) of PROPOFOL

    we measured the BISPECTRAL INDEX all through the protocol: from previous to start the infusion until 7 minutes after recovery of consciousness. values of BIS at LOC and ROC will be compared.

    a potential difference found between those two values supports the theory thas LOC and ROC reflects different neuronal processes Other clinically relevant endpoints (loss of palpebral reflex, onset of amnesia) will be registered in order to build the pharmacodynamic loop.

  2. Pharmacodynamic curve for propofol.

    Time frame: 2 hours

    plasma concentration of PROPOFOL (mcg/ml) at other clinically relevant endpoints (amnesia onset, loss of palpebral reflex, etc...) will be determined in order to build a pharmacodynamic curve,

  3. PROPOFOL effect site concentration during infusion

    Time frame: 2 hours

    plasma concentration of PROPOFOL (mcg/ml) from venous blood samples will be determinated every 7 minutes, that means at the end of each TCI step. assuming the 7-minute step gave enough time to reach a pseudo-equilibrium state, we consider the results comparable to effect site concentration.

Other outcomes

  1. performance of Schnider´s pharmacokinetic parameters in a slow infusion

    Time frame: 2 hours

    to compare plasma (and effect site) Propofol concentration predicted by the model with measured values thus evaluating model´s performance. Median performance error (MDPE) and median absolute performance error (MDAPE), divergence and other often reported parameters will be determinated.

  2. Electroencephalographic behavior at LOC and ROC during Propofol infusion

    Time frame: 2 hours (during propofol infusion)

    spectral analisis of 32-channel EEG during infusion. a specified time-frame around those two events (i.e.: 14 minutes) will be reconstructed in images and analyzed. cortical areas with enhanced activity and how do this activity changes during loss of consciousness and the recovery of it will be evaluated with a mathematical model in order two determine wether those events correspond with two different processes instead of a bidirectional single one.

Sponsors and collaborators

Lead sponsor

Universidad del Desarrollo

Other

Registry information

Official study title

Neuronal Inertia´s Effect on Pharmacological Behavior Representation of Propofol

Acronym: INERTIA

Important dates

Study start
2013
Primary completion
2013
Study completion
2013
First posted
Oct 14, 2013
Registry last updated
Oct 14, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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