Difference between spo2 and sao2 levels in patients NH phuc

Difference between SpO 2 and SaO 2 levels in patients with acute respiratory failure and development of a Nguyen Hoang Phuc, MD Dec 24, 2022 Nguyen Hoang Phuc 1* , Huynh Ha Xuyen 2 , Vo

Difference between SpO 2 and SaO 2 levels in patients with acute respiratory failure and development of a

Nguyen Hoang Phuc, MD

Dec 24, 2022

Nguyen Hoang Phuc 1* , Huynh Ha Xuyen 2 , Vo Minh Son 2 , Tran Nguyen Trong Phu 2,3

1 College of Health Sciences, VinUniversity, Ha Noi, Vietnam.

2 Can Tho University of Medicine and Pharmacy, Can Tho city 90000, Vietnam.

3 Faculty of Medicine, Chulalongkorn University, Thailand

OUTLINE

Acute respiratory failure (ARF) : the inability of the respiratory system to meet the oxygenation, ventilation, or metabolic requirements.

Two major types

 Hypoxemic

 Hypercapnic

The overall mortality rate of major ARF is 27-32%, severe ARF is 53-69%

1 Chinh LQ, Manabe T, Son DN, Chi NV, Fujikura Y, Binh NG, Co DX, Tuan DQ, Ton MD, Dai KQ, Thach PT, Nagase H, Kudo K, Nguyen DA Clinical epidemiology and mortality on patients with acute respiratory distress syndrome (ARDS) in Vietnam PLoS One 2019 Aug 15;14(8):e0221114 s

2 Cummings MJ, Baldwin MR, Abrams D, Jacobson SD, Meyer BJ, Balough EM, Aaron JG, Claassen J, Rabbani LE, Hastie J, Hochman BR, Salazar-Schicchi J, Yip NH, Brodie D, O'Donnell MR Epidemiology, clinical course, and outcomes of critically ill adults with COVID-19 in New York City: a prospective cohort study Lancet 2020 Jun 06;395(10239):1763-1770.

In Vietnam, mortality rate of severe ARF is approximately 57.1%1

Most patients with severe ARF has an etiology of pneumonia1, non-survivor made up 94.4%

During COVID-19 pandemic, up to 79% of hospitalized patients developed respiratory failure requiring invasive mechanical ventilation.2

ARF is diagnosed and further classified with Arterial Blood Gas (gold standard)

PaO2 is shown to strictly correlate with arterial oxygen saturation => using oxygen saturation

to monitor patients who are at risk or having ARF

Monitoring patients’ oxygen saturation with pulse oximeter (SpO2) is considered a standard of care (5 th vital sign)

Correct oxygen saturation measured with pulse oximeter can reduce ABG

It’s more viable, non-invasive, non-complicated, and costs lower compared to ABG

Studying the correlation between SpO2 and SaO2 in ARF patients

Studying factors that affect this correlation coefficient

Developing a SaO2 predictive model

Patients with

acute respiratory

hypoxemic failure

SpO2, ABG (SaO2, PaO2, pH)

Vital signs (Systolic/Diastolic Blood Pressure, Pulse, Temperature)

Demographic characteristics (Age,

Sex), Hemoglobin

Correlation between SpO2 and SaO2

Correlation between SpO2 and SaO2

among subgroups SaO2 predictive linear regression

model

125 patients above 16 years of age

Having ARHF Can Tho Central General Hospital

Patient recruitment

Time of study May 2019 – October 2020

Single-centered, descriptive study

Study design

PARTICIPANTS’ CHARACTERISTIC

Sex

Male Female

67 (53.6%)

58 (46.4%)

Acidosis/Alkalosis status

Acidosis (pH < 7.35) Alkalosis (pH > 7.45)

41 (32.8%)

35 (28%)

Age

16-64

> 64

50 (40%)

75 (60%)

Anemia status

Hb ≥ 11 g/L

Hb < 11 g/L

54 (43.2%)

71 (56.8%)

Body temperature

< 37.7 o C

≥ 37.7 o C

93 (74.4%)

32 (25.6%)

Systolic blood pressure

≥ 90 mmHg

< 90 mmHg

103 (82.4%)

22 (17.6%)

Pulse rate

60-100 bpm

> 100 pbm

51 (40.8%)

73 (58.4%)

SaO 2

Mean SD

93.406% 9.63%

FiO 2

21%-40%

40%-60%

60%-80%

80%-100%

93 (74.4%)

16 (12.8%)

7 (5.6%)

9 (7.2%)

SpO 2

Mean SD

88,224% 12,68%

SpO2 and SaO2 had a moderate degree Pearson's correlation coefficient (r = 0.391, p < 0,0001) Not correlated in subgroup analysis (67 patients with SpO2 below 95% (r = 0.18, p = 0.15))

Pearson’s correlation coefficient

Body temperature

< 37.7 o C

≥ 37.7 o C

-r = 0,395

-Pulse rate

60-100 bpm

> 100 pbm

r = 0,473

r = 0,356 Systolic blood pressure

≥ 90 mmHg

< 90 mmHg

-r = 0.434

-Anemia status

Hb ≥ 11 g/L

Hb < 11 g/L

r = 0,795

-Acidosis/Alkalosis status

Acidosis (pH < 7.35) Alkalosis (pH > 7.45)

-r = 0.425

-FiO2

21%-40%

40%-60%

60%-80%

80%-100%

r = 914

-r = 0.355

r = 0.451

-Bayesian Information Criterion algorithm was employed to select the best models

=> Model 4 was the best fit for

Comparing 2 models with and without interaction analysis

=> Model a had lower BIC

CONCLUSION

THANK YOU FOR YOUR

ATTENTION