Alternate Methodology of Pulse Oximeter Validation

Not Applicable

Suspended

• Conditions: Hypoxemia; Desaturation of Blood
• Interventions: Device: ROBD Step-Wise desaturation sequence; Device: RespirAct Step-Wise Hypocapnia desaturation sequence; Device: RespirAct Step-Wise Normocapnia desaturation sequence; Device: RespirAct Slope Normocapnia desaturation sequence; Device: RespirAct Slope Hypocapnia desaturation sequence

• Registration Number: NCT03628560
• Lead Sponsor: Duke University

Brief 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.

Detailed 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.

Study Timeline

• Study First Submitted: 2018-08-09
• Study First Submitted QC: 2018-08-09
• Study First Posted: 2018-08-14
• Study Start: 2018-09-26
• Status Verified: 2022-02
• Last Update Submitted: 2022-02-21
• Last Update Posted: 2022-03-08
• Primary Completion: 2023-01-30
• Study Completion: 2023-01-30

Recruitment & Eligibility

• Status: SUSPENDED
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Aged 18 - 50 years
• Subject is willing to provide written informed consent and is able to comply with anticipated study procedures

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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

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
ROBD Step-Wise desaturation sequence	ROBD Step-Wise desaturation sequence	ROBD = Reduced Oxygen Breathing Device. Reduction in oxygen saturation 100 to 70% in approximate 5% steps. This represents the standard type of desaturation sequence for pulse oximeter accuracy testing.
RespirAct Step-Wise Hypocapnia desaturation sequence	RespirAct Step-Wise Hypocapnia desaturation sequence	Reduction in oxygen saturation 100 to 70% in approximate 5% steps.
RespirAct Step-Wise Normocapnia desaturation sequence	RespirAct Step-Wise Normocapnia desaturation sequence	Reduction in oxygen saturation 100 to 70% in approximate 5% steps.
RespirAct Slope Normocapnia desaturation sequence	RespirAct Slope Normocapnia desaturation sequence	Reduction in oxygen saturation 100 to 70% as gradual slope.
RespirAct Slope Hypocapnia desaturation sequence	RespirAct Slope Hypocapnia desaturation sequence	Reduction in oxygen saturation 100 to 70% as gradual slope.

Primary Outcome Measures

Name	Time	Method
Accuracy of FDA-approved pulse oximeter when calculated with RespirAct-derived end-tidal PAO2 values and with co-oximeter measured arterial PaO2 values	1 study day	The unit of measure of accuracy is called A\[RMS\] and is a composite value of bias and precision.
PAO2 values	1 study day	RespirAct-derived end-tidal PAO2 values with co-oximeter measured arterial PaO2 values

Secondary Outcome Measures

Name	Time	Method
Accuracy, A[RMS], when a step-wise desaturation sequence is used against a slope desaturation sequence.	1 study day	The unit of measure of accuracy is called ARMS and is a composite value of bias and precision.
Level of PaCO2 (hypocapnia versus normocapnia)	1 study day

Trial Locations

Locations (1)

Duke University; 🇺🇸 Durham, North Carolina, United States