Hemodynamic Responses During Induction: Comparison of Marsh and Schnider Pharmacokinetic Models

NCT ID: NCT01759160

Last Updated: 2013-03-29

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2012-12-31
• Study Completion Date: 2013-01-31

Brief Summary

To compare the hemodynamic changes during anesthesia induction between Marsh and Schnider plasma TCI models. We put forward a hypothesis that, if one TCI model is associated with much more prominent vasodilation effect or cardiac depression, a more sharp decrease in mean arterial pressure, systemic vascular resistance , central venous return or stroke volume would be observed.

Detailed Description

Current systems of propofol TCI are pre-programmed with the Marsh and Schnider pharmacokinetic models. Rate constants of Marsh are fixed, whereas compartment volumes and clearances are weight proportional. Schnider model has fixed values for VC, V3, k13, and k31, adjusts V2, k12, and k21 for age, and adjusts k10 according to total weight, lean body mass (LBM), and height. One major benefit of the Schnider model is that it adjusts doses and infusion rates according to patient age. This provides a strong argument for using the Schnider model in the elderly and unwell patients which may improve hemodynamic stability and safety.

However for the vast majority of young and middle age patients, whether Marsh or Schnider would be a better choice for hemodynamic stability remains unknown.

With marsh model, as VC is scaled to body weight, the amount of drug delivered is dependent of body weight. In the Schnider model, as VC at 4.27L is independent of body weight, VC in terms of ml/kg decreases as body weight increases. This and the influence of height and weight on clearance results in heavier patients receiving less propofol on a mg/kg basis whereas those with a lower lean body mass will initially receive about 30% less than delivered by Marsh, but after 30 min, the Schnider model delivers about 15% more. Besides, when Schnider model is used in the morbidly obese, the LBM equation can generate paradoxical values resulting in excessive increases in maintenance infusion rates. Nevertheless, the purpose of this study was to investigate the vast majority of Asian patients whose body weight were in normal range. Only patients with BMI between 18 and 29 were included to minimize the influential factor of body weight in TCI system.

To compare the hemodynamic changes during anesthesia induction between Marsh and Schnider plasma TCI models. We put forward a hypothesis that, if one TCI model is associated with much more prominent vasodilation effect or cardiac depression, a more sharp decrease in mean arterial pressure, systemic vascular resistance , central venous return or stroke volume would be observed.

Conditions

Healthy

Keywords

Target control infusion; propofol; cardiac depression; induction of anesthesia; hemodynamics

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: SINGLE

Study Groups

Marsh

Marsh Plasma TCI with high initial target

Group Type: ACTIVE_COMPARATOR

Marsh Plasma TCI with high initial target

Intervention Type: PROCEDURE

plasma target-controlled infusion in Marsh model(n=30) with an initial target concentration of 4 μg/ml. Target was then reset and gradually titrated to a sedation level with narcotrend index below 64.

Schnider

Schnider Plasma TCI with high initial target

Group Type: ACTIVE_COMPARATOR

Schnider Plasma TCI with high initial target

Intervention Type: PROCEDURE

plasma target-controlled infusion in Schnider model(n=30) with an initial target concentration of 4 μg/ml. Target was then reset and gradually titrated to a sedation level with narcotrend index below 64.

Interventions

Marsh Plasma TCI with high initial target

plasma target-controlled infusion in Marsh model(n=30) with an initial target concentration of 4 μg/ml. Target was then reset and gradually titrated to a sedation level with narcotrend index below 64.

Intervention Type: PROCEDURE

Schnider Plasma TCI with high initial target

plasma target-controlled infusion in Schnider model(n=30) with an initial target concentration of 4 μg/ml. Target was then reset and gradually titrated to a sedation level with narcotrend index below 64.

Intervention Type: PROCEDURE

Other Intervention Names

Plasma target-controlled infusion in Marsh model; Plasma target-controlled infusion in Schnider model

Eligibility Criteria

Inclusion Criteria

• Patients between the ages of 18 years and 70 years
• ASA physical status I and II
• surgical procedures requiring general anesthesia with continuous CVP and arterial pressure monitoring.

Exclusion Criteria

• Patients younger than 16 y or older than 65 y
• Body Mass Index (BMI) <18 or >30
• emergency surgery
• allergy to any of the drugs used
• inability to communicate effectively
• severe cardiovascular dysfunction
• patient refusal and patients on long-term opioids or sedative medication.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

First Affiliated Hospital, Sun Yat-Sen University

OTHER

Sponsor Role: lead

Responsible Party

Xia Feng

Department of Anesthesiology

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Xia Feng, M.D.

Role: PRINCIPAL_INVESTIGATOR

The First Affiliaed Hospital of Sun Yat-sen University

Locations

The First Affiliated Hospital of Sun Yat-sen University

Guangzhou, Guangdong, China

Countries

China

References

Yang XY, Zhou ZB, Yang L, Zhou X, Niu LJ, Feng X. Hemodynamic responses during induction: comparison of Marsh and Schnider pharmacokinetic models. Int J Clin Pharmacol Ther. 2015 Jan;53(1):32-40. doi: 10.5414/CP202141.

Reference Type: DERIVED

PMID: 25500489 (View on PubMed)

Other Identifiers

Fengxia1

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

NSFCfengxiar1

Identifier Type: -

Identifier Source: org_study_id