Alternate Methodology of Pulse Oximeter Validation

Hypoxemia Clinical Trial

Official title:

Alternate Methodology of Pulse Oximeter Validation

Clinical Trial Details — Status: Suspended

Administrative data

• NCT number: NCT03628560
• Other study ID #: Pro00100105
• Status: Suspended
• Phase: N/A
• Start date: September 26, 2018
• Est. completion date: January 30, 2023

Study information

• Verified date: February 2022
• Source: Duke University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This study will determine if the replacement of the measured arterial blood oxygen saturation with expired (end-tidal) oxygen value is an acceptable method to calculate the accuracy of pulse oximeters.

Description:

Pulse oximeters are non-invasive devices that use light to display an estimate (denoted by SpO2) of the true arterial blood oxygen saturation (SaO2). The accuracy of the pulse oximeter is determined from desaturation sequences (reduction in SpO2 from 100 to 70%) performed in healthy volunteers. The current standard desaturation sequence is a step-wise reduction in 5% SpO2 increments, achieved by reduction in inspired oxygen delivered by a gas blender such as the ROBD (Reduced Oxygen Breathing Device). This mixes oxygen and nitrogen (components of air) to produce the desired gas mixture. Throughout the desaturation sequence arterial blood gas samples are drawn at each step. The blood gas samples are processed through a co-oximeter to measure the SaO2. For each SaO2 measurement there will be a corresponding SpO2 recorded. All data points from all subjects are amalgamated together to allow calculation of how well SpO2 corresponds to the SaO2 throughout the range of 70 - 100% oxygen saturation. Accuracy, A[RMS], is the unit of measure and this incorporates both bias and precision.

When the ROBD is used in a desaturation sequence, the subjects' arterial blood carbon dioxide (CO2) level will initially be normal (normocapnia). With the reduction in SpO2 during the desaturation sequence, the subjects' breathing rate will increase and this will cause the a physiological reduction in the blood CO2 value (hypocapnia). The extent of hypocapnia will vary from one subject to another. It is not known whether the presence of hypocapnia may have an effect upon the accuracy measurement.

The RespirAct is a gas blender which, in contrast to the ROBD, can control both the oxygen level as well as the carbon dioxide level. The end-tidal oxygen level (PAO2) is continuously displayed by the RespirAct during the desaturation sequence. The PAO2 closely approximates to arterial blood oxygen (PaO2) - the degree of closeness will be measured in the study. Through an accepted formula, the SaO2 can be derived from the measured PAO2. The derived SaO2 values can subsequently be used to measure the accuracy of the pulse oximeter. This A[RMS] can then be compared with the A[RMS] calculated from the blood gas co-oximeter PaO2 / SaO2 values. If the accuracies are comparable then this would remove the need for arterial line placement during pulse oximeter validation studies.

Eligible healthy volunteers will complete five (5) oxygen desaturation sequences with adjustment of sequence type and/or CO2 level. Two sequences will be delivered by step-wise reduction and two will be delivered by gradual slope. Two sequences will be delivered at normocapnia and two will be delivered at hypocapnia values. The ROBD sequence will be a step-wise reduction with CO2 value set by the subjects' own breathing control.

Recruitment information / eligibility

• Status: Suspended
• Enrollment: 30
• Est. completion date: January 30, 2023
• Est. primary completion date: January 30, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 50 Years

Eligibility

Inclusion Criteria:

• Aged 18 - 50 years

• Subject is willing to provide written informed consent and is able to comply with anticipated study procedures

Exclusion Criteria:

• Body Mass Index (BMI) < 18.0 or > 30.0

• Known significant respiratory, cardiovascular or medical condition that precludes study participation as judged by investigator

• Anemia [hemoglobin value below lower range of normal for gender]

• Abnormal hemoglobin electrophoresis result

• Exposure to nicotine [positive test at screening or study day]

• Abnormal drug screen [positive test at screening or on day of study]

• Positive pregnancy test for females [serum test at screening; urine test on study day]

• Abnormal Allen's test for collateral circulation

• Abnormal Electrocardiogram

• Abnormal Pulmonary Function Test

• Abnormal venous blood gas result

• Intolerance of facemask

Related Conditions & MeSH terms

• Desaturation of Blood
• Hypoxemia
• Hypoxia

Intervention

Device:
• RespirAct Step-Wise Normocapnia desaturation sequence
Blood carbon dioxide controlled at normal value (normocapnia).
• RespirAct Slope Normocapnia desaturation sequence
Blood carbon dioxide controlled at normal value (normocapnia).
• RespirAct Step-Wise Hypocapnia desaturation sequence
Blood carbon dioxide controlled at lower than normal value (hypocapnia).
• RespirAct Slope Hypocapnia desaturation sequence
Blood carbon dioxide controlled at lower than normal value (hypocapnia).
• ROBD Step-Wise desaturation sequence
Blood carbon dioxide is controlled at normal or lower value by subject's own breathing rate.

Locations

Country	Name	City	State
United States	Duke University	Durham	North Carolina

Sponsors (1)

Lead Sponsor	Collaborator
Duke University

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Accuracy of FDA-approved pulse oximeter when calculated with RespirAct-derived end-tidal PAO2 values and with co-oximeter measured arterial PaO2 values	The unit of measure of accuracy is called A[RMS] and is a composite value of bias and precision.	1 study day
Primary	PAO2 values	RespirAct-derived end-tidal PAO2 values with co-oximeter measured arterial PaO2 values	1 study day
Secondary	Accuracy, A[RMS], when a step-wise desaturation sequence is used against a slope desaturation sequence.	The unit of measure of accuracy is called ARMS and is a composite value of bias and precision.	1 study day
Secondary	Level of PaCO2 (hypocapnia versus normocapnia)		1 study day

External Links

•   Human Pharmacology & Physiology Lab at Duke University