Reader response
Myron Yaster MD
From Shoichi Uezono, MD Department of Anesthesiology, Jikei University, Tokyo JPN
We read Dr. Yaster’s commentary and the POSTer-Child study findings with great interest. While our recent study focused on adult patients in an intensive care setting, we believe our findings may provide complementary perspectives to the ongoing discussion on pulse oximetry accuracy across diverse populations.
In our single-center observational study of over 10,000 critically ill adult patients of East Asian descent, we evaluated the performance of the Nellcor Oxisensor-III (Covidien Japan Ltd.) in real-world ICU settings in Japan (Takagi et al., Chest, 2025). Using arterial co-oximetry as the reference standard, we identified a mean bias (SpO₂–SaO₂) of –1.2% overall, with bias increasing markedly (+6.4%) in patients with arterial saturations <90%. Of particular concern, “serious hidden hypoxemia” (SaO₂ <88% despite SpO₂ ≥92%) occurred in 0.6% of patients, and was associated with increased ICU readmission and hospital mortality.
We also identified two clinically relevant risk factors for SpO₂–SaO₂ dissociation: (1) chronic hemodialysis, possibly due to skin hyperpigmentation, and (2) impaired peripheral perfusion, especially in sepsis. Although our study focused on adults, these findings resonate with concerns raised in the pediatric setting about overestimation of oxygen saturation in patients with darker skin tones or low perfusion states.
We hope our contribution adds to the dialogue on improving pulse oximetry performance and equitable patient monitoring.
Citation:
Takagi T, Fujii T, Nakamura S, Tsutsumi Y, Uezono S. Accuracy of Pulse Oximetry and Risk Factors Associated With Discrepancy From Arterial Oxygenation in Asian Patients in the ICU: An Observational Study. Chest. 2025 Mar 18:S0012-3692(25)00298-3. doi: 10.1016/j.chest.2025.03.006. Epub ahead of print. PMID: 40113037.
From Pauline Wong and several other readers who wanted clarification on nail polish and pulse oximetry:
In response from the web: Black, blue, and green nail polish significantly lower oximeter readings of oxygen saturation. Blue and green produced greater decreases than purple and red; black produced an intermediate decrease.
From Mark Schreiner MD on Randall Flick’s assessment in last week’s Reader response of the article by Ranganathan and colleagues entitled; Postoperative Outcomes Following Preweekend Surgery (JAMA New Open. 2025 Mar 3;8(3):e2458794).
I totally agree with Randy. Several additional points are in order.
the outcomes are composites. I would have focused first on death because it is umambigous and obviously the most important.
this was a cohort study so the relative risks for individual outcomes could have been calculated at least for death before doing the logistic regression models. But the investigators only reported the multiple regression model yielding odds ratios not relative risks. Just addressing the relative risk of death at 30 days for example is gives a RR of 1.071 (95CI 92 - 1.25, P= 0.3775). Not very impressive.
the investigators don’t present their raw data for deaths and other outcomes. Back calculating from the % data shows an absolute difference risk difference of (0.16% - 0.15%) 0.01% or .0001. Pretty small.
How strong is the evidence? Odds ratios of 1.11 - 1.5 are considered weak associations, 1.5 - 3.0 are medium and > 3 are considered strong. In this study, the odds ratios were really weak associations.
From Dr Simon Whyte MBBS FRCA FRCPC, Head, Paediatric Anaesthesia, British Columbia’s Children’s Hospital, Clinical Associate Professor, UBC Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver, BC, Canada on the swiss cheese model.
Thanks for this excellent précis of the Safety Pyramid. Two comments really resonated with me. The first, referencing vaccination as an example, was about how successful practices eventually hide the consequences of failure. The second was on the importance of capacity as a component of safety. I think this means system capacity - flexibility, wiggle room. As an anesthesiologist, we think about physiological reserve & the importance of maximising this - writ large, that’s what medical pre-operative optimisation is trying to achieve. The parallel concept of system reserve is a useful way to think about the difference in likelihood between a near miss & a critical incident. The closer to the edge we operate the system, the less it takes to be tipped over it.
These two concepts meet when we think about how we design the system for running ORs (and hospitals). As a profession, we are intimately familiar with the constant tension between efficiency & safety in the way we run our ORs, & the need to balance the endless demand for more efficiency & operating capacity with the need to have enough reserve - to avoid decompensation. Unfortunately, there is a near-constant need to remind others that we work with - surgeons & administrators - of the “safety side” of this balancing act. I’m often confronted with the retort that historical data showing the increased harm that occurs from, for example, operating out of hours, is no longer relevant because modern day systems are safer/better/not comparable. I actually heard this argument in a meeting just this morning! Successes in changing the way we work have reduced risks; recency bias leads to people quickly forgetting how & why those changes came about & what drove them - examining the data on safety outcomes & using them to drive change towards greater safety.
A critical role of the modern anesthesiologist leader remains to advocate for & educate about the importance of system reserve.
From Myron Yaster MD on the death of Dr. Ron Miller MD. Although I never met him, Dr. Ron Miller was a legend. His seminal work on massive blood transfusions performed during his front line military service in the Viet Nam war and his pioneering work on the pharmacokinetics and dynamics of neuromuscular blocking agents were transformative to our profession. And of course, his textbook was the gold standard and got me and most of my colleagues through our written board examinations.
From the University of California San Francisco website:
It is with profound sadness that we share the news that Ronald D. Miller, MD, a visionary leader in anesthesiology, passed away on February 27, 2025. Dr. Miller served as Chair of the UCSF Department of Anesthesia and Perioperative Care from 1984 until 2009, and was one of the most successful physician-scientist-leaders in the field’s history.
Dr. Miller’s leadership was instrumental in guiding UCSF to the forefront of innovation in anesthesia, critical care, and perioperative medicine. His contributions to education, research, and clinical practice transformed the field. As the longtime editor of Miller’s Anesthesia, the most widely used textbook for anesthesia in the world, he played a pivotal role in advancing medical knowledge and training worldwide.
Beyond his academic achievements, Dr. Miller was a dedicated mentor, inspiring countless colleagues and trainees with his vision and passion for patient care and shaping generations of physicians and scientists. His impact on the field will continue to be felt for years to come.