Respiratory muscle strength and oxygenation as predictors of length of hospital stay in patients with COVID-19

The aim was to analyze the prognostic value of ventilation/ gas exchange dissociation markers to predict the treatment length in patients with the acute phase of COVID-19.
Materials and methods: The analysis was performed using a database of 384 randomly selected patients from December 2021 to May 2022 with a confirmed diagnosis of the acute phase of COVID-19, aged 61±16 years. Spirometry of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) was performed on 2,2±0,2 day of hospitalization with a portable MicroRPM device (CareFusion, UK) and measurement of surrogate oxygenation index (SpO2/FiO2), ROX index (SpO2/ FiO2)/respiratory rate) was carried out in all patients. Log-regression models were used (STATISTICA 10) to determine cutoff values for these functional variables and their ability to predict the patients length of hospital stay from the date of examination (≤ 7 vs > 7 days).
Results: The lowest sensitivity (SE) and specificity (SP) were shown in models using only the respiratory muscle strength markers MIP (SE=54%, SP=70%) and MEP (SE=73%, SP=47%), that were the same in the combination of MIP and MEP (SE=65%, SP=58%). The areas under ROC were equal to 0.6 in all three models. The models based on hypoxia markers had a higher classification power (AUC 0,7) compared to the previous three, and the sensitivity value was higher in the model using the ROX index (SE = 58% and SP = 78%), but the specificity was better in the surrogate oxygenation index model (SE = 48% and SP = 88%). A complex model based on a combination of the two integral hypoxia indices, as well as a diaphragm strength marker (SpO2/FiO2+MIP*ROX+MIP) had the best sensitivity (67%) and specificity (84%), and the area under ROC reached 0.8.
Conclusion: Indicators of respiratory muscle strength and oxygenation are suitable markers for combined models and algorithms for predicting hospital length of stay in COVID-19 patients.

1. Yamada G, Hayakawa K, Matsunaga N et al. Predicting respiratory failure for COVID-19 patients in Japan: a simple clinical score for evaluating the need for hospitalisation. Epidemiology and Infection.2021; 149, e175, 1–9. https://doi.org/10.1017/S0950268821001837.

2. Garcia-Gordillo JA, Camiro-Zúñiga A, -Soto M, et al. COVID-IRS: A novel predictive score for risk of invasive mechanical ventilation in patients with COVID-19. PLoS One. 2021;16(4):e0248357. Published 2021 Apr 5. doi: 10.1371/journal.pone.0248357.

3. Karonova T.L., Korsakov I.N., Mikhailova A.A., Lagutina D.I., Chernikova A.T., Vashukova М.A., Smolnikova M.A., Gusev D.A., Konradi A.O., Shlyakhto E.V. An artificial intelligence approach for prognosis of COVID-19 course in hospitalized patients. Journal Infectology. 2023;15(3):60-66. (In Russ.) https://doi.org/10.22625/2072-6732-2023-15-3-60-66

4. Kas’janenko K.V., Kozlov K.V., Zhdanov K.V., Lapikov I.I., Belikov V.V. SARS-CoV-2 severity prediction in young adults using artificial intelligence. Journal Infectology. 2022;14(5):14-25. (In Russ.) https://doi.org/10.22625/2072-6732-2022-14-5-14-25

5. Zaboli A, Ausserhofer D, Pfeifer N, et al. The ROX index can be a useful tool for the triage evaluation of COVID-19 patients with dyspnoea. J Adv Nurs. 2021;77(8):3361-3369. doi:10.1111/jan

6. Rahman A, Tabassum T, Araf Y, Al Nahid A, Ullah MA, Hosen MJ. Silent hypoxia in COVID-19: pathomechanism and possible management strategy. Mol Biol Rep. 2021;48(4):3863-3869. doi: 10.1007/s11033-021-06358-1.14848.

7. Levitan R. Pulse oximetry as a biomarker for early identification and hospitalization of COVID-19 pneumonia. AcadEmerg Med. 2020;27(8):785–786.

8. Camporota L, Vasques F, Sanderson B, Barrett NA, Gattinoni L. Identification of pathophysiological patterns for triage and respiratory support in COVID-19.Lancet Respir Med. 2020;8(8):752-754. doi:10.1016/S2213-2600(20)30279-4.

9. Frija-Masson J, Debray MP, Gilbert M, et al. Functional characteristics of patients with SARS-CoV-2 pneumonia at 30 days post-infection. Eur Respir J. 2020;56(2):2001754. Published 2020 Aug 6. doi:10.1183/13993003.01754-2020б 9FrijaMasson J, Debray MP, Gilbert M, et al. Functional characteristics of patients with SARS-CoV-2 pneumonia at 30 days postinfection. Eur Respir J. 2020;56(2):2001754. Published 2020 Aug 6. doi: 10.1183/13993003.01754-2020б

10. 10, Mo X, Jian W, Su Z, et al. Abnormal pulmonary function in COVID-19 patients at time of hospital discharge. Eur Respir J. 2020;55(6):2001217. Published 2020 Jun 18. doi: 10.1183/13993003.01217-2020.

11. Frat JP, Thille AW, Mercat A et al. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med 2015; 372:2185–2196. https ://doi.org/10.1056/ nejmo a1503 326

12. Zinserling V.А., Vashukova М.А., Vasilyeva М.V., Isakov А.N., Lugovskaya N.А., Narkevich Т.А., Sukhanova Yu.V., Semenova N.Yu., Gusev D.А. Issues of pathology of a new coronavirus infection COVID-19. J Infectologii. 2020;12(2): 5-11. DOI: 10.22625/2072-6732-2020-12-2-5-11. (in Russian).

13. Scala R, Heunks L. Highlights in acute respiratory failure. Eur Respir Rev.2018;27(147):180008. doi: 10.1183/16000617.0008-2018.].1

14. Vlasenko A.I., Portik O.A., Bisaga G.N., Topuzova M.P., Malko V.A., Isabekova P.Sh., Skripchenko N.V., Alekseeva T.M. Relationship between SARS-COV-2 And autoimmune neurological diseases. Journal Infectology. 2022;14(2):65-72. (In Russ.) https://doi.org/10.22625/2072-6732-2022-14-2-65-72

15. Shi Z, de Vries HJ, Vlaar APJ, van der Hoeven J, Boon RA, Heunks LMA, et al. Diaphragm pathology in critically ill patients with COVID-19 and postmortem findings from 3 medical centers. JAMA Intern Med 2021;181:122–124.

16. Pan’ko E.S., Zhavoronok S.V., Solovchuk A.M., Pan’ko S.S., Pan’ko S.V. Predictors of length of hospital stay in patients with acute COVID-19. Journal Infectology. 2023;15(1):86-92. (In Russ.) https://doi.org/10.22625/2072-6732-2023-15-1-86-92

17. Lu X, Jiang L, Chen T, et al. Continuously available ratio of SpO2/FiO2 serves as a noninvasive prognostic marker for intensive care patients with COVID-19. Respir Res. 2020;21(1):194. Published 2020 Jul 22. doi:10.1186/s12931-020-01455-4.

18. Babu S, Abhilash KP, Kandasamy S, Gowri M. Association between SpO2/FiO2 Ratio and PaO2/FiO2 Ratio in Different Modes of Oxygen Supplementation. Indian J Crit Care Med. 2021;25(9):1001-1005. doi:10.5005/jp-journals-10071-23977

19. Mukhtar A, Rady A, Hasanin A, et al. Admission SpO2 and ROX index predict outcome in patients with COVID-19. Am J Emerg Med. 2021;50:106-110. doi: 10.1016/j.ajem.2021.07.049

20. Zucman N, Mullaert J, Roux D, Roca O, Ricard JD, Contributors Prediction of outcome of nasal high flow use during COVID-19-related acute hypoxemic respiratory failure. Intens Care Med.2020 Oct;46(10):1924–1926.

21. Zaccagnini G, Berni A, Pieralli F. Correlation of noninvasive oxygenation parameters with paO2/FiO2 ratio in patients with COVID-19 associated ARDS. Eur J Intern Med. 2022;96:117-119. doi: 10.1016/j.ejim.2021.12.015

22. Xu J, Yang X, Huang C, et al. A Novel Risk-Stratification Models of the High-Flow Nasal Cannula Therapy in COVID-19 Patients With Hypoxemic Respiratory Failure. Front Med (Lausanne). 2020;7:607821. Published 2020 Dec 8. doi:10.3389/fmed.2020.607821

23. Zaboli A, Ausserhofer D, Pfeifer N, et al. The ROX index can be a useful tool for the triage evaluation of COVID-19 patients with dyspnoea. J Adv Nurs. 2021;77(8):3361-3369. doi: 10.1111/jan.14848

24. Koyauchi T, Yasui H, Enomoto N, et al. Pulse oximetric saturation to fraction of inspired oxygen (SpO2/FIO2) ratio 24 hours after high-flow nasal cannula (HFNC) initiation is a good predictor of HFNC therapy in patients with acute exacerbation of interstitial lung disease. Ther Adv Respir Dis. 2020;14:1753466620906327. doi: 10.1177/1753466620906327

25. Rahman A, Tabassum T, Araf Y, Al Nahid A, Ullah MA, Hosen MJ. Silent hypoxia in COVID-19: pathomechanism and possible management strategy. Mol Biol Rep. 2021;48(4):3863-3869. doi: 10.1007/s11033-021-06358-1

26. Scarpino M, Bonizzoli M, Lazzeri C, et al. Electrodiagnostic findings in patients with non-COVID-19- and COVID-19-related acute respiratory distress syndrome. Acta Neurol Scand. 2021;144(2):161-169. doi:10.1111/ane.13433