12 October 2021 : Review article
Silent Hypoxemia in Patients with COVID-19 Pneumonia: A Review
Lizhe Guo12E, Zhaosheng Jin3F, Tong J. Gan3E, E Wang12A*DOI: 10.12659/MSM.930776
Med Sci Monit 2021; 27:e930776
Background
Microvascular Thrombosis-Related Hypoxemia in COVID-19 Patients
Patients with COVID-19 are Prone to Alkalosis
SARS-CoV-2 is Dependent on Porphyrins and Attacks the 1-beta Chain of Hemoglobin
Endogenous Carbon Monoxide and Carboxyhaemoglobin Accumulation in Patients with Severe COVID-19
Other Non-Specific Factors Causing the Discrepancy Between Pulse Oximetric Oxygen Saturation and the Partial Pressure of Oxygen
COVID-19 Monitoring and Treatment Optimization
Conclusions
References
Table 1 The arterial blood gas of a 37-year-old male patient diagnosed with COVID-19 was found to have undergone ECMO due to silent hypoxemia despite being mechanically ventilated. Blood gas analysis showed that FCOHb was increased, and SaO2 was significantly lower than SpO2.
| Pre-ECMO | On-ECMO | Normal range | |
|---|---|---|---|
| SpO (%) | 95% | 95% | 95~100 |
| pH | 7.39 | 7.29 | 7.35~7.45 |
| pCO (mmHg) | 40.4 | 40.1 | 35~45 |
| pO (mmHg) | 43.2 | 46.0 | 80~100 |
| Hb (g/dl) | 8.6 | 8.7 | 12.0~17.5 |
| SaO (%) | 83.6 | 86.5 | 93~98 |
| FCOHb (%) | 7.1 | 8.3 | 0~1.5 |
| FMetHb (%) | 1.4 | 1.3 | 2~7 |
| Base excess (mmol/L) | −0.3 | −6.4 | −3~3 |
| Lactate (mmol/L) | 1.9 | 7.0 | 0.5~1.6 |
| Glucose (mmol/L) | 7.1 | 9.9 | 3.9~5.8 |
| K (mmol/L) | 4.4 | 3.7 | 3.4~5.5 |
| COVID-19 – coronavirus disease-2019; ECMO – extracorporeal membrane oxygenation; SpO – pulse oximetric oxygen saturation; SaO – arterial oxygen saturation; FCOHb – fraction of carboxyhaemoglobin; pCO – partial pressure of carbon dioxide; pO – partial pressure of oxygen; Hb – hemoglobin; FMetHb – fraction of methemoglobin. | |||