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

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.

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Key information

Conditions

Anaesthesia

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Copenhagen, Glostrup Hospital

Copenhagen, Glostrup, 2600, Denmark

About this study

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.

Who can participate

Healthy volunteers accepted: No

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

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.

Treatment and study plan

Primary outcomes

Change in the regional cerebral oxygen saturation

Time frame: 15 seconds

Measured by Near Infrared Spectroscopy

Secondary outcomes

The duration before the steady state in the regional cerebral oxygen saturation is obtained after changing the head position.

Time frame: 15 seconds

Sponsors and collaborators

Lead sponsor

Glostrup University Hospital, Copenhagen

Other

Registry information

Official study title

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.

Important dates

Study start: 2013
Primary completion: 2014
Study completion: 2014
First posted: Oct 30, 2013
Registry last updated: Jul 2, 2014

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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