Effects of continuous blood purification on the scavenging capacity of oxygen free radicals and inflammatory factors in severe pneumonia patients

 Severe pneumonia is a respiratory system disease with acute pulmonary parenchymal lesions caused by bacterial, viral and other pathogens. It is characterized by sudden onset, complex condition and relatively high mortality, and is one of the common diseases leading to death in respiratory department [1]. Investigation data show that the death rate of severe pneumonia can reach more than 50% [2]. The massive release of inflammatory factors and the large amount of oxygen free radicals produced by oxidative stress are one of the main causes of the occurrence and development of severe pneumonia. If effective treatment is not taken in time, patients are highly likely to suffer from respiratory failure, leading to multiple organ dysfunction [3-4]. At present, despite the continuous development and application of new anti-infection drugs, the fatality rate in primary hospitals has not been significantly improved, and most patients will leave pulmonary fibrosis and other complications after recovery. In addition, long hospital stay and high cost are also one of the reasons that lead to patients missing the best treatment opportunities. Continuous blood purification has been widely used in clinical treatment of critically ill patients in recent years. Its main mechanism of action is to remove all kinds of harmful molecules through blood purification, so as to block the further development of the disease [5]. The purpose of this study was to investigate the effects of continuous blood purification combined with routine treatment on oxygen free radical scavenging capacity and inflammatory factors in patients with severe pneumonia, and to provide clinical reference. The report is as follows.

1. Data and methods

1.1 General Data A total of 188 patients with severe pneumonia who were admitted to the Department of Respiratory Medicine of Chongqing Armed Police Corps Hospital from January 2019 to December 2020 were selected as the research subjects. Inclusion criteria: The diagnostic criteria of all patients met those of severe pneumonia in literature [6] and literature [7]. Exclusion criteria: complicated lung tumor and pulmonary tuberculosis; Severe heart, liver and kidney dysfunction; Allergic constitution; Abnormal coagulation function; There is a tendency to bleed. They were divided into control group and observation group by random drawing, with 94 cases in each group. This study has been approved by the Medical Ethics Committee of Chongqing Armed Police Corps Hospital, and the patients' families have no objection to this study and voluntarily signed informed consent.

1.2 Methods After admission, both groups were actively given oxygen inhalation, expectoration, auxiliary ventilation, anti-infection treatment and other comprehensive treatment measures, and the treatment plan was adjusted according to the clinical condition changes and sputum culture results. Patients with basic diseases should pay attention to the treatment and medication of basic diseases. The observation group was treated with continuous blood purification on the basis of the above treatment regimen. The method is as follows: The patient established vascular access through the right femoral vein or internal jugular vein, and underwent extracorporeal circulation hemofiltration using Baxter BM25 continuous renal replacement therapy instrument and supporting pipeline filter. The replacement fluid was Port formula, with a total volume of 3 500 mL and a flow rate of 2.5-3.5 L/h. During the treatment, the blood flow velocity was adjusted according to the patient's hemodynamic changes, and anticoagulation intervention was conducted according to the patient's condition. The hemofiltration time was 6-8 h, and the treatment lasted for 7 days.

1.3 Observation indicators and criteria (1) Clinical efficacy. Significant effect: after 7 days of treatment, the symptoms of dyspnea disappeared completely and no recurrence was observed at 48 h. PaO2 was no less than 80 mmHg. Effective: After 7 days of treatment, symptoms and signs such as dyspnea and heart rate were significantly improved, and PaO2 was increased. Ineffective: The clinical symptoms, signs and blood gas analysis indicators were not improved after 7 days of treatment [8]. Total effectiveness = significant + effective. (2) Blood gas analysis indicators. Blood oxygen partial pressure (PaO2), partial pressure of carbon dioxide (PaCO2) and oxygenation index (PaO2/FiO2) were measured by automatic blood gas analyzer before and after treatment for 7 d. (3) Oxidative stress index. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in serum of the two groups were determined by colorimetry before and after 7 days of treatment. (4) Levels of inflammatory factors. The levels of inflammatory factors including tumor necrosis factor -α (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8) in both groups were determined by enzyme-linked immunosorbent assay before and after treatment for 7 d.

1.4 Statistical Analysis SPSS 22.0 software was used for statistical analysis. Measurement data were expressed as (x± S). Independent sample T test was used for inter-group comparison, and paired T test was used for intra-group comparison. The count data were expressed as %, and χ2 test was used for comparison. In order to P< 0.05 was considered statistically significant.

2 the results

2.1 Comparison of general data between the two groups: control group, 60 males and 34 females; The average age was (52.18±3.46) years from 23 to 74 years. There were 79 cases of community-acquired pneumonia and 15 cases of hospital acquired pneumonia. Complications: diabetes 27 cases, hypertension 18 cases. Observation group, 62 males, 32 females; The average age was (52.65±3.37) years from 23 to 76 years. There were 80 community-acquired pneumonia cases and 14 hospital-acquired pneumonia cases. Complications: diabetes 28 cases, hypertension 20 cases. There was no significant difference in gender, age and other general data between the two groups (P> 0.05), with comparability.

2.2 Comparison of clinical efficacy between the two groups The total effective rate was 95.74% in the observation group and 84.04% in the control group, the difference between the two groups was statistically significant (χ2=7.084, P< 0.05), see Table 1.

2.3 Comparison of blood gas indexes between the two groups before and after treatment, there was no statistical significance in the comparison of blood gas indexes between the two groups before treatment (P> 0.05); After 7 days of treatment, PaO2 and PaO2/FiO2 in both groups were higher than before, and the observation group was higher than the control group (P< 0.05); After 7 days of treatment, PaCO2 in both groups was lower than before, and the observation group was lower than the control group (P< 0.05). Are shown in table 2.

2.4 Comparison of oxidative stress indexes between the two groups before and after treatment, there was no statistically significant difference in oxidative stress indexes between the two groups before treatment (P> 0.05); After 7 days of treatment, SOD increased and MDA decreased in both groups, and the observation group was better than the control group, the differences were statistically significant (P< 0.05). See table 3.

2.5 Comparison of the levels of inflammatory factors between the two groups before and after treatment there was no statistical significance in the levels of inflammatory factors between the two groups before treatment (P> 0.05); After 7 days of treatment, the levels of inflammatory factors in both groups were lower than before, and the observation group was lower than the control group, the differences were statistically significant (P< 0.05). See table 4.

3 discuss

Severe pneumonia patients with airway endocrine a large number of inflammatory mediators, not only cause lumen stenosis, but also can lead to alveolar wall congestion and edema, and then lead to ventilation and ventilation dysfunction, induce respiratory failure. In addition to respiratory symptoms, patients are often accompanied by septic shock, multiple organ failure and other serious complications, resulting in a further increase in the risk of death [9-10]. Relevant research reports have found that the massive diffusion of inflammatory factors in patients with severe pneumonia is significantly related to the development trend of the disease, and the continuously released inflammatory mediators can cause a cascade reaction, ultimately leading to multi-organ failure [11]. As is known to all, the body in the condition of normal physiological metabolism, oxygen free radical production and the clearance is in a state of dynamic balance, when inflammation, pathogenic factor of the function break the balance, excess oxygen beyond the body's ability to remove free radicals, lipid peroxidation in the biofilm, can damage the structure and function of biological membrane [12-14]. Studies have shown that the degree of lipid peroxidation damage in the body is positively correlated with the severity of severe pneumonia in children [15]. Therefore, the clinical treatment of severe pneumonia is not only to relieve the clinical symptoms and signs, but also to pay attention to the index levels of inflammatory factors and oxygen free radicals.

The working principle of continuous blood purification is to use the principle of convection to filter out a large number of inflammatory mediators and cytokines in the body by simulating the function of the kidney, so as to block or reduce systemic inflammatory response syndrome and ultimately achieve the purpose of blocking the development of the disease [16-18]. TNF-α, IL-6 and IL-8 are pro-inflammatory factors produced by inflammatory cells and are also the main pathological basis of systemic inflammatory response [19]. In this study, after 7 days of treatment, the levels of inflammatory factors in both groups were lower than before, and the observation group was lower than the control group, the differences were statistically significant (P< 0.05). Since SOD reflects the ability of the body to clear oxygen free radicals, while MDA reflects the content of oxygen free radicals in the body [20-21], this study selected SOD and MDA for comparative analysis, and the results showed that before treatment, there was no statistical significance in the comparison of oxidative stress indexes between the two groups (P> 0.05); After 7 days of treatment, SOD increased and MDA decreased in both groups, and the observation group was better than the control group, the differences were statistically significant (P< 0.05). In addition, by comparing the clinical efficacy and changes of blood gas analysis indexes before and after treatment, it was found that the clinical efficacy of observation group was higher than control group (P< 0.05); After 7 days of treatment, PaO2 and PaO2/FiO2 in both groups were higher than before, and the observation group was higher than the control group (P< 0.05); After 7 days of treatment, PaCO2 in both groups was lower than before, and the observation group was lower than the control group (P< 0.05). Show that evolutionary continuity blood for improving the blood gas index of patients with severe pneumonia more helpful, investigate its reason lies in the continuity of blood serum inflammatory factors in patients with severe pneumonia evolution and oxygen free radical removal ability is stronger, not only can reduce the patients with systemic inflammatory response, and through the way of extracorporeal circulation to remove excess water from the patient's body, To a certain extent, it can reduce the pulmonary edema of patients with severe pneumonia, improve the ability of lung tissue to use oxygen, and then effectively improve the pulmonary ventilation and ventilation function.

In conclusion, continuous blood purification treatment for severe pneumonia patients can effectively remove oxygen free radicals, reduce oxidative stress damage, reduce the level of inflammatory factors, improve blood gas analysis indicators, and promote patient rehabilitation, which is worthy of clinical promotion.