The Occurrence And Prognosis Analysis Of Hyperoxemia In Critically Ill Patients Under Invasive Mechanical Ventilation

Objective:To investigate the clinical characteristics and prognosis of hyperoxemia in critically ill patients with invasive mechanical ventilation in intensive care unit（ICU）,so as to improve the cognition of clinical medical staff on hyperoxemia and provide a basis for oxygen therapy supported by invasive mechanical ventilation.Methods:This study retrospectively collected 124 critically ill patients who received invasive mechanical ventilation in ICU Unit 1,Affiliated Hospital of Guilin Medical College from June 2021 to June 2022,and recorded the results of their first arterial blood gas analysis after mechanical ventilation 72 hours after intubation.Include arterial partial pressure of oxygen（Pa O₂）,arterial partial pressure of carbon dioxide（Pa CO₂）,difference of partial pressure of oxygen in alveolar artery（P（A-a）DO₂）,oxygenation index（Pa O₂/Fi O₂）,fraction of inspired oxygen（Fi O₂）,arterial oxygen saturation measured by arterial blood gas co-oximetry（Sa O₂）and lactic acid（Lac）,serum lactate dehydrogenase（LDH）,creatine kinase（CK）,creatine kinase isoenzyme（CK-MB）and other clinical data.According to the level of Pa O₂,patients were divided into hyperoxemia group（Pa O₂≥120mm Hg）and non-hyperoxemia group（70mm Hg≤Pa O₂<120mm Hg）,and the clinical indicators of the two groups were compared.In addition,according to the Pa O₂ value,the patients with hyperoxemia were divided into mild hyperoxemia group,moderate hyperoxemia group and severe hyperoxemia group（defined as 120～140mm Hg group,140～160mm Hg group and>160mm Hg group,respectively）,and the clinical related indicators of the three groups were compared.Finally,according to the clinical outcome of the patients,they were divided into the improvement group and the death group,and the clinical indicators between the two groups were compared.Correlations between Pa O₂ and other parameters in all patients were analyzed.Results:（1）The Lac of non-hyperoxemia group was significantly higher than that of hyperoxemia group（P<0.05）.The levels of CK and CK-MB in the hyperoxemia group were significantly higher than those in the non-hyperoxemia group（P<0.05）.There was no significant difference in LDH between hyperoxemia group and non-hyperoxemia group（P>0.05）.（2）The Lac value of the severe hyperoxia group and the mild hyperoxia group was higher than that of the moderate hyperoxia group,and the difference was statistically significant（P<0.05）.There was no significant difference between the severe hyperoxia group and the moderate hyperoxia group（P>0.05）.The CK value of the severe hyperoxia group was significantly higher than that of the mild hyperoxia group（P<0.05）,and there was no significant difference among the other groups（P>0.05）.The level of CK-MB in the severe hyperoxia group was significantly higher than that in the mild hyperoxia group and the moderate hyperoxia group（P<0.05）,and there was no significant difference in the other groups（P>0.05）.（3）Pa O₂,Lac and Fi O₂ in the death group were significantly higher than those in the improvement group（P<0.05）.CK、CK-MB、Pa CO₂、LDH and Sp O₂ were not significantly different between the two groups（P>0.05）.（4）Pa O₂ was positively correlated with Fi O₂（r=0.144,P=0.023）,Sa O₂（r=0.787,P<0.05）and Pa O₂/Fi O₂（r=0.728,P<0.05）in all patients.It was negatively correlated with Pa CO₂（r=-0.376,P<0.05）and P（A-a）DO₂（r=-0.5,P<0.05）,and there was no significant correlation with hemoglobin（P>0.05）.Conclusions:1.The deliberate pursuit of normal blood oxygen saturation in critically ill patients will not correct the hypoxia state,but may lead to the occurrence of hyperoxemia,which will further aggravate the disorder of internal environment and lead to the increase of Lac.2.In the condition of hyperoxemia,the high Pa O₂ value may lead to the damage of myocardial cells;3.Avoiding the occurrence of hyperxemia may be beneficial to improve the clinical prognosis of critically ill patients with invasive mechanical ventilation;4.The high concentration of oxygen therapy,the one-sided pursuit of normal oxygen saturation of the finger pulse and some measures taken to reduce Pa CO₂ may lead to the occurrence of hyperxemia.