Measuring the Effect of External Pressure on the Regional Cerebral Oxygen Saturation Monitored by Near-infrared Spectroscopy(NIRS) Technology

Measuring the Cerebral Oxygen Saturation With NIRS Sensor Placed on the Forehead of Patients in the Prone Position. How Does the External Pressure Affect the Measurement.

During general anaesthesia, to ensure sufficient oxygen supply to the brain, the NIRS technology can be used. It consist of two sensors placed on the forehead, and measures the oxygen saturation of the tissue underneath the sensor. For patients undergoing back surgery placed in the prone position, the NIRS measurement will be affected, because the weight of the head will produce a pressure on the sensors. We wish to investigate how much the measurement is affected. Furthermore we plan to lift the head to remove the pressure, and record the time needed for the measurements to return to baseline.

Study Overview

• Status: Completed
• Conditions: Anaesthesia

Detailed Description

When placed in the prone position an external pressure is applied to the NIRS sensor. This pressure changes the amount of blood in the underlying tissue and thereby has an influence on the regional cerebral oxygen saturation measured. We wish to investigate to which extend this value is affected by the external pressure. Furthermore by lifting the head we want to investigate how long takes for the measurements to return to baseline (no pressure in the supine position).

Patients will receive written and oral information about the study, when seen by an anaesthesiologist prior to surgery. Before the anaesthesia one NIRS sensors is placed on the right side of the forehead, avoiding til frontal sinus, and one NIRA sensor is placed on the left musculus deltoideus. The patient is placed in the prone position with the head in af prone-view face mask. Measurements will start after 30 minutes with no change in infusion rate of anaesthetic and no inotropics administered. Registration of NIRS measurements will be done every 15 seconds, first five minutes without intervention, then five minutes with headlift, and last five minutes without interventions. Blood pressure, pulse, saturation, end-tidal carbon dioxide and temperature, will be recorded. Registration wil be om case report forms.

• Study Type: Observational
• Enrollment (Actual): 60

Contacts and Locations

Study Locations

• Denmark
  • Glostrup
    • Copenhagen, Glostrup, Denmark, 2600
      • University of Copenhagen, Glostrup Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients undergoing lumbar spine surgury, and are placed in the prone position

Description

Inclusion Criteria:

• Surgery in the lumbar spine, in the prone position, with the head in a proneview facemask
• Free and painless movement of the neck

Exclusion Criteria:

• Known cervical spine pathology.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Lumbar spine surgical patients; Patients undergoing lumbar spine surgery in the prone position

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in the regional cerebral oxygen saturation	Measured by Near Infrared Spectroscopy	15 seconds

Secondary Outcome Measures

Outcome Measure	Time Frame
The duration before the steady state in the regional cerebral oxygen saturation is obtained after changing the head position.	15 seconds

Collaborators and Investigators

• Sponsor: Glostrup University Hospital, Copenhagen
• Investigators: Principal Investigator: Johnny DH Andersen, M.D., University of Copenhagen, Glostrup Hospital, Denmark; Principal Investigator: Hanna Siegel, M.D., University of Copenhagen, Glostrup Hospital, Denmark

Publications and helpful links

General Publications

• Siegel H, Andersen JD, Nielsen RV, Lorentzen K, Olsen KS. Measuring regional cerebral oxygen saturation during surgery in the prone position. Eur J Anaesthesiol. 2016 Feb;33(2):154-5. doi: 10.1097/EJA.0000000000000289. No abstract available.

Study record dates

Study Major Dates

• Study Start: November 1, 2013
• Primary Completion (Actual): May 1, 2014
• Study Completion (Actual): May 1, 2014

Study Registration Dates

• First Submitted: October 24, 2013
• First Submitted That Met QC Criteria: October 24, 2013
• First Posted (Estimate): October 30, 2013

Study Record Updates

• Last Update Posted (Estimate): July 2, 2014
• Last Update Submitted That Met QC Criteria: July 1, 2014
• Last Verified: July 1, 2014

More Information

Terms related to this study

• Keywords: Near infrared Spectroscopy
• Other Study ID Numbers: H-4-2013-FSP