Influence of respiratory rate-oxygenation index combined with chest CT on respiratory treatment decisions in patients with acute hypoxic respiratory failure related to corona virus disease 2019 infection

doi:10.3877/cma.j.issn.1674-6880.2025.02.005

Abstract

Abstract:

Objective

To analyze the influence of respiratory rate-oxygenation (ROX) index combined with chest CT on respiratory treatment decisions in patients with acute hypoxic respiratory failure (AHRF) related to corona virus disease 2019 infection (COVID-19).

Methods

A total of 62 adult patients with COVID-19-related AHRF who initiated high-flow nasal cannula oxygen therapy (HFNC) after the failure of conventional oxygen therapy in the Minda Hospital of Hubei Minzu University were retrospectively included from March 2020 to March 2024. The indications for mechanical ventilation (MV) were judged by attending physicians of the patients.All patients underwent CT examinations immediately after admission. The proportion of lung infiltration volume (LIV) was calculated through chest CT image analysis using 3D Slicer software. The clinical characteristics of all patients were recorded and the ROX index was calculated approximately 6 hours after admission. Multivariate logistic regression analysis was used to evaluate risk factors for the need of MV in patients with COVID-19-related AHRF. The area under the curve (AUC) and cutoff value of the ROX index and/or LIV for predicting the MV required by patients were analyzed using a receiver operating characteristic (ROC) curve.

Results

According to whether they received MV or not, 62 patients with COVID-19-related AHRF were divided into a HFNC group (35 cases) and a MV group (27 cases). At admission,the hemoglobin, creatinine, lactic dehydrogenase and LIV of patients in the MV group were significantly higher than those in the HFNC group, while the ROX index was significantly lower,and the time from the onset of the disease to admission and the time from the onset of the disease to the initiation of HFNC were significantly shorter (all P ＜0.05). Multivariate logistic regression analysis showed that the ROX index ≤6.55 [odds ratio (OR)=0.141, 95% confidence interval (CI) (0.023, 0.885),P = 0.037] and LIV ＞ 33.45% [OR = 40.012, 95%CI (4.833,331.273), P=0.001] were independent risk factors for MV treatment in patients with COVID-19-related AHRF. ROC curve analysis showed that the combination of ROX index and LIV had ideal efficacy in predicting the need for MV treatment in patients with COVID-19-related AHRF(AUC: 0.939; sensitivity: 92.59%; specificity: 82.86%). According to the prognosis at 28 days,62 patients with COVID-19-related AHRF were divided into a death group (6 cases) and a survival group (56 cases). After analysis, the ROX index of AHRF patients in the death group was significantly lower than that in the survival group [3.80 (3.00, 4.70) vs. 7.05 (5.40, 8.65),Z=3.549, P ＜0.001], while LIV was significantly higher [46.75% (44.20, 65.90)% vs. 32.90%(25.20, 37.45)%, Z=3.786, P ＜0.001].

Conclusion

The LIV combined with ROX index shown by chest CT can provide support and guidance for physicians in the decision-making of respiratory management (HFNC or MV) in patients with COVID-19-related AHRF.

Key words: Respiratory rate-oxygenation index, Chest computed tomography, Acute hypoxic respiratory failure, Lung infiltration volume

Jiao Xiang, Ying Su, Yaming Lan. Influence of respiratory rate-oxygenation index combined with chest CT on respiratory treatment decisions in patients with acute hypoxic respiratory failure related to corona virus disease 2019 infection[J]. Chinese Journal of Critical Care Medicine(Electronic Edition), 2025, 18(02): 115-121.

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Figures/Tables 5

指标	HNFC 组（n= 35）	MV 组（n= 27）	t / χ² / Z值	P值
年龄（岁， $\overset{ˉ}{x}$ ± s ）	59 ± 15	61 ± 12	0.617	0.540
男性[例（%）]	26（74.29）	20（74.07）	＜ 0.001	0.985
BMI（kg / m²， $\overset{ˉ}{x}$ ± s ）	25 ± 4	27 ± 6	1.337	0.186
实验室检验
血红蛋白（g / L， $\overset{ˉ}{x}$ ± s ）	291 ± 59	339 ± 76	2.758	0.008
乳酸[mmol / L，M（P₂₅，P₇₅）]	2.10（1.30，3.30）	2.50（1.65，4.60）	0.966	0.334
PLT[× 10⁹ / L，M（P₂₅，P₇₅）]	197.0（127.0，338.0）	214.0（154.5，280.5）	0.099	0.921
WBC[× 10⁹ / L，M（P₂₅，P₇₅）]	6.2（5.2，11.5）	7.1（5.3，11.6）	0.469	0.639
肌酐[μmol / L，M（P₂₅，P₇₅）]	66.30（57.02，77.79）	98.13（67.63，133.04）	2.855	0.004
CRP[mg / L，M（P₂₅，P₇₅）]	88.9（33.1，144.4）	112.5（49.3，155.0）	0.802	0.422
LDH[U / L，M（P₂₅，P₇₅）]	387.0（348.5，429.0）	449.0（372.0，704.0）	2.563	0.010
PT[s，M（P₂₅，P₇₅）]	16.00（14.35，20.20）	16.50（13.65，21.10）	0.043	0.966
DD[μg / L，M（P₂₅，P₇₅）]	0.80（0.60，1.45）	1.20（0.80，2.25）	1.940	0.052
PSI[M（P₂₅，P₇₅）]	79.0（67.0，109.5）	89.0（75.0，149.0）	1.519	0.129
SOFA[分，M（P₂₅，P₇₅）]	6.0（4.5，11.0）	6.0（3.0，8.5）	1.347	0.178
APACHEⅢ评分[分，M（P₂₅，P₇₅）]	66.00（46.00，87.00）	50.00（43.50，79.00）	1.222	0.222
CCI[M（P₂₅，P₇₅）]	1.00（1.00，2.00）	2.00（1.00，2.00）	1.116	0.264
ROX 指数[M（P₂₅，P₇₅）]	7.90（6.30，9.65）	5.30（4.55，6.50）	4.304	＜ 0.001
LIV[%，M（P₂₅，P₇₅）]	26.30（22.00，33.15）	40.60（35.70，44.15）	5.374	＜ 0.001
发病至入院时间（d，， $\overset{ˉ}{x}$ ± s ）	9.7 ± 2.7	7.7 ± 3.2	2.678	0.010
发病至启动HFNC 时间（d， $\overset{ˉ}{x}$ ± s ）	9.8 ± 2.7	7.5 ± 2.6	3.326	0.002

指标	HNFC 组（n= 35）	MV 组（n= 27）	t / χ² / Z值	P值
年龄（岁， $\overset{ˉ}{x}$ ± s ）	59 ± 15	61 ± 12	0.617	0.540
男性[例（%）]	26（74.29）	20（74.07）	＜ 0.001	0.985
BMI（kg / m²， $\overset{ˉ}{x}$ ± s ）	25 ± 4	27 ± 6	1.337	0.186
实验室检验
血红蛋白（g / L， $\overset{ˉ}{x}$ ± s ）	291 ± 59	339 ± 76	2.758	0.008
乳酸[mmol / L，M（P₂₅，P₇₅）]	2.10（1.30，3.30）	2.50（1.65，4.60）	0.966	0.334
PLT[× 10⁹ / L，M（P₂₅，P₇₅）]	197.0（127.0，338.0）	214.0（154.5，280.5）	0.099	0.921
WBC[× 10⁹ / L，M（P₂₅，P₇₅）]	6.2（5.2，11.5）	7.1（5.3，11.6）	0.469	0.639
肌酐[μmol / L，M（P₂₅，P₇₅）]	66.30（57.02，77.79）	98.13（67.63，133.04）	2.855	0.004
CRP[mg / L，M（P₂₅，P₇₅）]	88.9（33.1，144.4）	112.5（49.3，155.0）	0.802	0.422
LDH[U / L，M（P₂₅，P₇₅）]	387.0（348.5，429.0）	449.0（372.0，704.0）	2.563	0.010
PT[s，M（P₂₅，P₇₅）]	16.00（14.35，20.20）	16.50（13.65，21.10）	0.043	0.966
DD[μg / L，M（P₂₅，P₇₅）]	0.80（0.60，1.45）	1.20（0.80，2.25）	1.940	0.052
PSI[M（P₂₅，P₇₅）]	79.0（67.0，109.5）	89.0（75.0，149.0）	1.519	0.129
SOFA[分，M（P₂₅，P₇₅）]	6.0（4.5，11.0）	6.0（3.0，8.5）	1.347	0.178
APACHEⅢ评分[分，M（P₂₅，P₇₅）]	66.00（46.00，87.00）	50.00（43.50，79.00）	1.222	0.222
CCI[M（P₂₅，P₇₅）]	1.00（1.00，2.00）	2.00（1.00，2.00）	1.116	0.264
ROX 指数[M（P₂₅，P₇₅）]	7.90（6.30，9.65）	5.30（4.55，6.50）	4.304	＜ 0.001
LIV[%，M（P₂₅，P₇₅）]	26.30（22.00，33.15）	40.60（35.70，44.15）	5.374	＜ 0.001
发病至入院时间（d，， $\overset{ˉ}{x}$ ± s ）	9.7 ± 2.7	7.7 ± 3.2	2.678	0.010
发病至启动HFNC 时间（d， $\overset{ˉ}{x}$ ± s ）	9.8 ± 2.7	7.5 ± 2.6	3.326	0.002

自变量	赋值		回归系数	标准误	Wald 值	OR 值	95%CI	P值
自变量	0	1	回归系数	标准误	Wald 值	OR 值	95%CI	P值
血红蛋白（g / L）	≤302.0	＞ 302.0	0.831	0.905	0.843	2.296	0.390 ～ 13.526	0.358
肌酐（μmol / L）	≤72.05	＞ 72.05	0.368	0.965	0.146	1.445	0.218 ～ 9.580	0.703
LDH（U / L）	≤417.0	＞ 417.0	1.379	0.924	2.226	3.971	0.649 ～ 24.311	0.136
ROX 指数	≤6.55	＞ 6.55	-1.958	0.937	4.370	0.141	0.023 ～ 0.885	0.037
LIV（%）	≤33.45	＞ 33.45	3.689	1.078	11.701	40.012	4.833 ～ 331.273	0.001
发病至入院时间（d）	≤9.0	＞ 9.0	-1.072	1.079	0.986	0.342	0.041 ～ 2.839	0.321
发病至启动HFNC 时间（d）	≤9.0	＞ 9.0	-0.966	1.046	0.854	0.380	0.049 ～ 2.953	0.355

变量	AUC	95%CI	P值	敏感度（%）	特异度（%）	截断值	阳性预测值（%）	阴性预测值（%）
ROX 指数	0.821	0.702 ～ 0.907	＜ 0.001	66.67	85.71	5.80	83.28	70.66
LIV（%）	0.901	0.798 ～ 0.962	＜ 0.001	77.78	91.43	35.60	90.65	79.40
ROX 指数+ LIV	0.939	0.847 ～ 0.984	＜ 0.001	92.59	82.86	0.25	85.23	91.28

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