1. Accuracy of Pulse Oximetry in Mechanically Ventilated Adults
A G Sankari-Tarbichi, MD1, M Zamlut, MD1 , S. Ansari, MD1 and A O Soubani, MD1. 1Wayne State University,
Detroit, MI, United States.
A G Sankari-Tarbichi, MD1,2, M Zamlut, MD2 and A O Soubani, MD1.2. 1Wayne State University; 2Detroit Medical Center, Detroit, MI, USA.
ABSTRACT
ABSTRACT
ABSTRACT
HYPOTHESES
RESULTS
1- Pulse oximetry is accurate in critically ill adults who are on invasive mechanical ventilation
2- Vasopressors do not affect pulse oximetry accuracy
3- Accuracy of pulse oximetry is decreased in black race vs. non-black.
Accuracy of pulse oximetry in mechanically ventilated adults. A G Sankri-Tarbichi, MD1, M Zamlut, MD1 and A O Soubani, MD1. 1Wayne State University, Detroit, MI, United States.
Pusle oximetry is routinely used in the intensive care units (ICU) for continuous oxygenation assessment. In critically ill patients, however, when peripheral tissue is poorly perfused, the signal from the pulsatile blood flow is impaired leading to a less accurate estimate of SaO2. The purpose of this study is to examine the accuracy of pulse oximeter in ICU patients who are on mechanical ventilation in comparison to SaO2 obtained by simultaneous arterial blood gas (ABG). Secondary outcome is to examine the detrimental effect of vasopressors on the accuracy of pulse oximetry measurements. Design: Prospective observational study in tertiary care medical ICU. Measurements: pulse oximetry obtained simultaneously with ABG, vital signs, and use of vasopressors. Inclusion criteria: All adult patients aged yo who are admitted to intensive care unit and mechanically ventilated. Exclusion criteria: Age <18 yo, severe anemia (Hgb <8), pregnancy, Methemoglobulinemia, Carbon monoxide exposure or toxicity, and pigmented skin. SpO2 and O2 Sat from 91 mechanically ventilated patients were compared using Bland-Altman analysis. 24 patients (25%) had vasopressors during the data collection. Results: see table
Conclusion: Oxygen saturation can be accurately measured using pulse oximetry in mechanically ventilated patients. Vasopressors do not impair the accuracy of pulse oximetry measurements above 90%.
Design
Prospective observational study in tertiary care medical ICU
Measurements
Pulse oximetry measurements obtained simultaneously with ABG, vital signs, use of vasopressors, and underlying illness.
Inclusion criteria: All adult patients aged yo who are admitted to intensive care unit e and mechanically ventilated. Exclusion criteria: Age <18 yo, severe anemia (Hgb <8), pregnancy, Methhemoglobulinemia, Carbon monoxide exposure or toxicity, and pigmented skin.
Accuracy of pulse oximetry in mechanically ventilated patients
Accuracy of pulse oximery in mechanically ventilated patients when vasopressors are used
RESULTS
Vasopressor
(VP)
No VP
Black
Non-Black
All N 28 93 72 49
121
Age (yrs)
61.3 ±10
61.3 ±14
62.1 ±15
60.3 ± 11
60.1 ± 15
Gender (F) 13 42 38 66
BMI
30.0± 9
28.4 ±8
29.3 ± 8
28.0 ± 8
APACHE IV
106.6 ± 22
95.5 ±27
98.7 ± 28
97.9±23
98.6±28
SpO2 (%)
97.3± 3.3
98.7± 2.5
98.9 ± 1.7
97.5± 3.6
98.9 ±1.7
SaO2 (%)
95.5± 1.5
96.3± 2.8
96.2 ± 3.0
96.1± 2.9
96.2± 3.0
Sp-aO2
(%)
1.7± 1.8
2.4 ±3.1
2.8 ±2.9*
1.4 ±2.6
2.7 ±2.8
Accuracy of pulse oximetry black patients
Pulse oximetry is less accurate in black patients
INTRODUCTION
Pusle oximetry is routinely used in the intensive care units (ICU) for continuous oxygenation assessment.
In critically ill patients, however, when peripheral tissue is poorly perfused, the signal from the pulsatile blood flow is impaired leading to a less accurate estimate of arterial oxygen saturation (SaO2).
There is uncertainty about the accuracy of pulse oximetry used in critically ill patients in comparison to SaO2.
DISCUSSION
Oxygen saturation can be accurately measured using pulse oximetry in mechanically ventilated adults patients.
Vasopressors do not impair the accuracy of pulse oximetry measurements above 90%.
Black race affects the accuracy of pulse oximetry in critically ill adults
SpO2, pulse oximetry; SaO2,arterial oxygen saturation, BMI, body mass index, *p<0.05