The INSPIRE trial analysis suggests no clinically significant difference in accuracy between light and dark skin tones among critically ill patients.
Key takeaways:
- An exploratory analysis published in CHEST Critical Care evaluated Masimo SET pulse oximetry in a real-world ICU setting.
- The study found zero occult hypoxemic events among 50 critically ill patients of varying skin tones.
- Results showed an overall accuracy of 1.47% ARMS, falling within FDA specifications for laboratory studies.
- The feasibility study paves the way for a larger prospective trial involving 502 patients.
Masimo announced findings from an exploratory analysis of a feasibility study published in CHEST Critical Care, which indicates that Masimo SET pulse oximetry performed accurately among critically ill adult patients of all skin tones.
Conducted by Andrew Goodwin, MD, and colleagues at the Medical University of South Carolina (MUSC), the study reported zero occult hypoxemic events and found that the device performed accurately even in patients with low perfusion requiring vasopressors.
The study utilized a design that allowed researchers to conduct an accuracy study within a hospital environment. Unlike typical accuracy studies conducted in controlled laboratories with healthy volunteers, this trial compared arterial blood saturation (SaO2) values obtained invasively at clinical discretion with time-synchronized pulse oximetry saturation (SpO2) values.
In this analysis, researchers examined data from the first 50 of a planned 502 patients. The team enrolled 107 adult patients at two ICUs within the MUSC main hospital between January and July 2024, yielding a sample size of 50 patients who had at least one clinically indicated blood draw collected while the study team was present.
Skin pigmentation was assessed using a validated noninvasive hand-held skin colorimeter, grouping patients into dark and light skin tone categories based on individual topology angle.
The researchers found that among the 49 patients and 80 data pairs meeting technical criteria, Masimo SET pulse oximetry demonstrated an overall accuracy of 1.47% root-mean-squared (ARMS). This figure aligns with FDA accuracy specifications for Masimo RD SET sensors in no motion and motion conditions (1.5% ARMS) and outperforms the industry-standard specification of 3% ARMS.
According to the data, the median bias between noninvasive SpO2 and invasive SaO2 was -0.6%, which researchers deemed not clinically significant. Additionally, the difference between the median bias for dark skin tone and light skin tone patients was 0.7% (-0.2% vs -0.9%), a difference that was statistically but not clinically significant.
“Masimo SET was chosen for our INSPIRE trial because of its industry-leading accuracy,” says Goodwin, principal investigator and section chief of critical care at MUSC, in a release. “We are pleased to add to the growing body of evidence for pulse oximetry research in varying skin tones. Our feasibility study has demonstrated that we are closer to a definitive answer regarding how the Masimo SET sensor performs in a real-world ICU environment. Although not yet definitive, our preliminary results suggest that Masimo SET performs accurately on all skin tones.”
The study design aims to address limitations often observed in other studies, such as using self-reported race as a surrogate for skin pigmentation or relying on retrospective designs. By using the INSPIRE design, the authors note they can examine the outcome of occult hypoxemia—where low oxygen saturation is not reflected in pulse oximetry readings—in a vulnerable population.
“The concern for dangerously overestimating blood oxygen levels with pulse oximetry is greatest among critically ill and poorly perfused patients with dark skin tone who are often moving,” says Daniel Cantillon, MD, chief medical officer at Masimo, in a release. “We’re highly encouraged to see no occult hypoxemia events so far and that the unique INSPIRE study design can prospectively measure that performance in a real-world setting.”
Data collection for the full INSPIRE trial is ongoing. The researchers aim to publish the full results next year, which will analyze the effect of skin pigmentation on pulse oximeter accuracy across the complete dataset.
