Hemodynamic Changes and Propofol Pharmacokinetic Variation During Anesthesia Induction and Knee-chest Positioning

Not Applicable

Completed

• Conditions: Hemodynamic Instability; Anesthesia; Surgery
• Interventions: Drug: Propofol reduction

• Registration Number: NCT03961958
• Lead Sponsor: University of Salamanca

Brief Summary

Induction of anesthesia and the knee-chest position are associated with hemodynamic changes that may impact patient outcomes.

Changes from baseline in cardiac output and other hemodynamic variables following induction of anesthesia and knee-chest positioning were compared. Propofol plasma concentrations were also measured after induction of anesthesia and after the knee-chest position.

The aim of this study was to assess whether planned reductions in target-controlled infusion propofol concentrations attenuate the hemodynamic changes associated with anesthesia induction and knee-chest position.

The secondary aim was to quantify the variation in propofol measured plasma concentrations (Cm), both after induction and after KC positioning, and correlate them with predicted concentrations (Cp) by the Schnider Pk model.

Detailed Description

A total of 20 patients scheduled for elective lumbar spinal surgery in the knee-chest position were included. In addition to standard anesthesia monitoring, bispectral index and noninvasive cardiac output monitoring were undertaken. The study was carried out in 2 parts. In phase 1, target-controlled infusion propofol anesthesia was adjusted to maintain BIS 40 to 60. In phase 2, there were 2 planned reductions in propofol target concentration: (1) immediately after loss of consciousness: reduction calculated using a predefined formula, and (2) before positioning: reduction equal to the average percentage decrease in CO after knee-chest position in phase 1.

Study Timeline

• Study Start: 2009-07
• Primary Completion: 2014-01
• Study Completion: 2014-01
• Status Verified: 2019-05
• Study First Submitted: 2019-05-11
• Study First Submitted QC: 2019-05-22
• Last Update Submitted: 2019-05-22
• Study First Posted: 2019-05-23
• Last Update Posted: 2019-05-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Lumbar spinal condition for surgical treatment in knee-chest position

Exclusion Criteria

• Severe ischemic heart disease
• Congestive heart failure
• Atrial fibrillation or flutter
• Body mass index > 35 kg/m2
• Glasgow Coma Scale < 15
• Dementia disease
• History of drug abuse or addiction
• Consumption of opioid medication
• Pre-operative administration of midazolam

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Two protocolled propofol reductions	Propofol reduction	In phase 2, there were 2 planned reductions in propofol target concentration: (1) immediately after loss of consciousness-reduction calculated using a predefined formula, and (2) before positioning-reduction equal to the average percentage decrease in CO after knee-chest position in phase

Primary Outcome Measures

Name	Time	Method
Hemodynamic changes	Baseline (moment 0), 10 minutes after induction of anesthesia (moment 1), 10 minutes after knee-chest positioning (moment 2)	Changes from baseline in cardiac output and comparison of the changes between both groups.

Secondary Outcome Measures

Name	Time	Method
Pharmacokinetic changes	Baseline (moment 0), 10 minutes after induction of anesthesia (moment 1), 10 minutes after knee-chest positioning (moment 2)	Correlation between propofol measured plasma concentrations and predicted plasma concentrations (Cp) by the Schnider Pk model.

Trial Locations

Locations (1)

Centro Hospitalar do Porto; 🇵🇹 Porto, Portugal