Pulse Oximetry in Severe Carbon Monoxide Poisoning

doi:10.1378/chest.114.4.1036

Chest

Volume 114, Issue 4, October 1998, Pages 1036-1041

https://doi.org/10.1378/chest.114.4.1036 Get rights and content

Study objectives

To evaluate the accuracy and quantitate the error of pulse oximetry measurements of arterial oxygenation in patients with severe carbon monoxide (CO) poisoning.

Design

Retrospective review of patient clinical records.

Setting

Regional referral center for hyperbaric oxygen therapy.

Patients

Thirty patients referred for treatment of acute severe CO poisoning who demonstrated carboxyhemoglobin (COHb) levels >25%, with simultaneous determinations of arterial hemoglobin oxygen saturation by pulse oximetry (SpO₂) and arterial blood gas (ABG) techniques.

Measurements and results

COHb levels and measurements of arterial oxygenation from pulse oximetry, ABG analysis, and laboratory CO oximetry were compared. SpO₂ did not correlate with COHb levels. SpO₂ consistently overestimated the fractional arterial oxygen saturation. The difference between arterial hemoglobin oxygen saturation (SaO₂) calculated from ABG analysis and SpO₂ increased with increasing COHb level.

Conclusions

Presently available pulse oximeters overestimate arterial oxygenation in patients with severe CO poisoning. An elevated COHb level falsely elevates the SaO₂ measurements from pulse oximetry, usually by an amount less than the COHb level, confirming a prior observation in an animal model. Accurate assessment of arterial oxygen content in patients with CO poisoning can currently be performed only by analysis of arterial blood with a laboratory CO-oximetry.

Section snippets

MATERIALS AND METHODS

Records of all patients treated with hyperbaric oxygen for acute CO poisoning at Virginia Mason Medical Center in Seattle from December 1988 to November 1997 were screened. Those with measured COHb values >25.0% as determined by CO oximetry of arterial or venous blood were reviewed in detail. Charts of patients with documented simultaneous measurement of arterial hemoglobin oxygen saturation by pulse oximetry (SpO₂), arterial blood gas (ABG) values (arterial pH [pHa], PacO₂, PaO₂), and COHb

RESULTS

In the decade reviewed, 740 patients were treated for acute CO poisoning with hyperbaric oxygen. Among those, 30 had COHb levels >25.0% in conjunction with documented simultaneous ABG analysis and measurement of SpO₂. As these measurements were performed in the emergency departments of referring hospitals and abstracted from medical records transferred with the patient, information regarding the brand or model of pulse oximeter, ABG analyzer, and CO-oximetry was not available.

A total of 22 male

DISCUSSION

Pulse oximetry is a noninvasive method for measurement of arterial oxygenation. Several excellent reviews describing the method have been published.3, 8, 16 In brief, the technique transmits two wavelengths of light through tissue (typically 660 and 940 nm), measuring changes in absorbance at each wavelength over time. Light absorption by tissue is cyclic due to cardiac cycling and the resultant pulsation of arterial blood into the tissue bed. The pulse oximeter measures the change in light

REFERENCES (18)

MowerWR et al.
Effect of routine emergency department triage pulse oximetry screening on medical management
Chest
(1995)
BuckleyRG et al.
The pulse oximetry gap in carbon monoxide intoxication
Ann Emerg Med
(1994)
VegforsM et al.
Carboxyhaemoglobinaemia and pulse oximetry
Br J Anaesth
(1991)
HampsonNB.
Emergency department visits for carbon monoxide poisoning in the Pacific Northwest
J Emerg Med
(1998)
LambertMA et al.
The role of pulse oximetry in the accident and emergency department
Arch Emerg Med
(1989)
TremperKK et al.
Pulse oximetry
Anesthesiology
(1989)
RalstonAC et al.
Potential errors in pulse oximetry: I. Pulse oximeter evaluation
Anaesthesia
(1991)
LindbergLG et al.
Pulse oximetry—clinical implications and recent technical developments
Acta Anaesthesiol Scand
(1995)
MardirossianG et al.
Limitations of pulse oximetry
Anesth Prog
(1992)

There are more references available in the full text version of this article.

Cited by (130)

Impact of ethnicity on the accuracy of measurements of oxygen saturations: A retrospective observational cohort study
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Pulse oximeters are routinely used in community and hospital settings worldwide as a rapid, non-invasive, and readily available bedside tool to approximate blood oxygenation. Potential racial biases in peripheral oxygen saturation (SpO2) measurements may influence the accuracy of pulse oximetry readings and impact clinical decision making. We aimed to assess whether the accuracy of oxygen saturation measured by SpO2, relative to arterial blood gas (SaO2), varies by ethnicity.
In this large retrospective observational cohort study covering four NHS Hospitals serving a large urban population in Birmingham, United Kingdom, consecutive pairs of SpO2 and SaO2 measurements taken on the same patient within an interval of less than 20 min were identified from electronic patient records. Where multiple pairs of measurements were recorded in a spell, only the first was included in the analysis. The differences between SpO2 and SaO2 measurements were compared across groups of self-identified ethnicity. These differences were subsequently adjusted for age, sex, bilirubin, systolic blood pressure, carboxyhaemaglobin saturations and the time interval between SpO2 and SaO2 measurements.
Paired O2 saturation measurements from 16,818 inpatient spells between 1st January 2017 and 18th February 2021 were analysed. The cohort self-identified as being of White (81.2%), Asian (11.7%), Black (4.0%), or Other (3.2%) ethnicities. Across the cohort, SpO2 was statistically significantly higher than SaO2 (p < 0.0001), with medians of 98% (interquartile range [IQR]: 95–100%) vs. 97% (IQR: 96–99%), and a median difference of 0.5% points (pps; 95% confidence interval [CI]: 0.5–0.6). However, the size of this difference varied considerably with the magnitude of SaO2, with SpO2 overestimating by a median by 3.8pp (IQR: 0.4, 8.8) for SaO2 values <90% but underestimating by a median of 0.4pp (IQR: -2.0, 1.4) for an SaO2 of 95%. The differences between SpO2 and SaO2 were also found to vary by ethnicity, with this difference being 0.8pp (95% CI: 0.6–1.0, p < 0.0001) greater in those of Black vs. White ethnicity. These differences resulted in 8.7% vs. 6.1% of Black vs. White patients who were classified as normoxic on SpO2 actually being hypoxic on the gold standard SaO2 (odds ratio: 1.47, 95% CI: 1.09–1.98, p = 0.012).
Pulse oximetry may overestimate O2 saturation, and this is possibly more pronounced in patients of Black ethnicity. Prospective studies are urgently warranted to assess the impact of ethnicity on the accuracy of pulse oximetry, to ensure care is optimised for all.
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Chest

Clinical Investigations: Pulmonary FunctionPulse Oximetry in Severe Carbon Monoxide Poisoning

Study objectives

Design

Setting

Patients

Measurements and results

Conclusions

Section snippets

MATERIALS AND METHODS

RESULTS

DISCUSSION

Chest

Ann Emerg Med

Br J Anaesth

J Emerg Med

The role of pulse oximetry in the accident and emergency department

Arch Emerg Med

Pulse oximetry

Anesthesiology

Potential errors in pulse oximetry: I. Pulse oximeter evaluation

Anaesthesia

Pulse oximetry—clinical implications and recent technical developments

Acta Anaesthesiol Scand

Limitations of pulse oximetry

Anesth Prog

Clinical Investigations: Pulmonary Function
Pulse Oximetry in Severe Carbon Monoxide Poisoning