When facing severe patients with COVID-19, nephrologists must master these key points of treatment!

With the full release of the epidemic, a new round of epidemic shock waves has reached third- and fourth-tier cities. However, the current impact of the epidemic has put the medical system under tremendous pressure to treat patients, and it also threatens the lives of patients with severe kidney disease and hemodialysis. In order to improve the success rate of treatment for kidney patients and reduce the mortality rate, Yilu Shenkang has compiled the clinical diagnosis and treatment strategies for kidney patients infected with COVID-19 for clinical reference.

First of all, in principle, the treatment of mild cases of COVID-19 is completely different from that of severe cases. The treatment of mild cases currently mainly advocates self-treatment at home, while the core of severe cases is supportive treatment, that is, adjusting the oxygen supply according to the patient's respiratory condition, adjusting the fluid replacement according to the patient's volume condition, and simultaneously carrying out antiviral infection, anticoagulation and other treatments. The specific treatment measures are as follows.

1. Conventional treatment

1. Oxygen therapy

The respiratory system is the main target organ attacked by the COVID-19 virus, and hypoxemia is a key link in the treatment of COVID-19 infection. Clinically, it is necessary to use various oxygen therapy methods for patients with hypoxemia on the basis of close monitoring and dynamic evaluation to quickly improve the patient's hypoxic state and provide a basis for other treatments. For patients with hypoxemia with oxygen saturation <93% or Pa0/FiO2 between 200 and 300 mmHg, the following treatments can be selected.

(1) Oxygen inhalation via nasal cannula: The oxygen flow rate generally does not exceed 5 L/min; maintenance refers to oxygen saturation > 93%.

(2) Ordinary mask oxygen therapy: If nasal cannula oxygen inhalation cannot maintain an oxygen saturation > 93%, mask oxygen therapy can be considered. The oxygen flow rate is recommended to be controlled at 5 to 10 L/min.

(3) High-flow nasal cannula oxygen therapy: When respiratory distress and/or hypoxemia do not improve after receiving oxygen inhalation via nasal cannula or mask, high-flow nasal cannula oxygen therapy should be used instead. For patients with severe/critical COVID-19 whose oxygen saturation is less than 93% at rest, high-flow nasal cannula oxygen therapy can also be used directly. During treatment, the patient's spontaneous respiratory drive should be closely monitored. If necessary, non-invasive mechanical ventilation can be used to quantify the patient's respiratory drive strength to guide the adjustment of oxygen therapy and related treatments.

(4) Mechanical ventilation: For patients with hypoxemia whose Pa0/Fi02 is between 150 and 200 mmHg, non-invasive mechanical ventilation support can be attempted. If the hypoxia still does not improve or even worsens, and Pa0/FiO is <150 mmHg, invasive mechanical ventilation should be given in a timely manner. The setting principles of invasive mechanical ventilation mode and parameters should follow the lung protective mechanical ventilation strategy. For patients with moderate to severe acute respiratory distress syndrome, or when Fi02 is continuously higher than 50%, lung recruitment therapy can be attempted, and whether to perform lung recruitment techniques repeatedly can be decided based on the patient's lung recruitment responsiveness.

2. Antiviral treatment

For patients with COVID-19 nucleic acid positive for less than 5 days and no contraindications such as liver and kidney dysfunction, namatevir/ritonavir can be used to treat specific IgM and IgG antibodies, especially IgG antibodies, which may have a neutralizing effect, which is conducive to clearing the virus and promoting recovery. For patients with IgG below 10 mg/L, neutralizing antibodies and specific immunoglobulins can be used for treatment. For patients with high-risk factors, high viral load, and rapid disease progression, convalescent plasma can be used in the early stage of the disease, with an infusion dose of 200-500 mL (4-5 mL/kg), and then decide whether to infuse again based on the individual situation of the patient and viral load.

3. Immunomodulatory therapy

Based on the results of large randomized controlled trials such as RECOVERY, patients with COVID-19 who have a high inflammatory response and are in the progressive stage of imaging can be given a low dose (5 mg of dexamethasone or an equivalent dose of other glucocorticoids) and a short course (within 10 days) of glucocorticoids. Thymosin alpha 1 is a commonly used immunomodulator in clinical practice. Thymosin alpha 1 can be used for patients with low absolute lymphocyte counts. For patients with severe/critical COVID-19, intravenous human immunoglobulin 5 to 20 g/d can be given. However, the use of human immunoglobulin may cause renal failure and thrombotic events in patients, so it should be used with caution in patients with hypercoagulable states, and the patient's organ function should be closely monitored during use.

4. Anticoagulant therapy

Related studies have shown that the incidence of venous thromboembolism during hospitalization of COVID-19 patients can be as high as 26%. Based on the pathogenic mechanism of COVID-19, COVID-19 patients without bleeding tendency should be given anticoagulant drugs, and high-risk patients should be routinely monitored for coagulation function and screened for deep vein thrombosis. Low molecular weight heparin is the first choice for anticoagulant drugs, and ordinary heparin can be used for patients with renal dysfunction. When a patient has a thromboembolic event, thrombolysis and other treatments should be performed in accordance with the corresponding guidelines.

II. Prevention and treatment of patients with kidney disease and hemodialysis

For COVID-19 patients with underlying kidney disease or renal impairment, on the basis of routine management, it is necessary to keep in mind the principle of "two assessments, one indication, and two treatments", that is, to give priority to assessing whether renal function is normal, whether there are signs of renal failure, whether dialysis is needed immediately, as well as the treatment during dialysis and the management of complications. The details are as follows:

1. Renal function assessment: The renal function of patients with COVID-19 should be assessed upon admission to the hospital. If the patient has delayed dialysis or significant increases in blood urea nitrogen and blood creatinine, dialysis treatment should be arranged promptly.

2. Assessment of complications of renal failure: Assessment of complications of renal failure includes cardiac function, electrolytes (especially blood potassium), water and acid-base balance, blood pressure, gastrointestinal function, anemia, nutrition and other aspects.

3. Indications for emergency dialysis: Maintenance hemodialysis patients who have delayed dialysis, have a significant increase in blood creatinine, and develop acute left heart failure, hyperkalemia, severe acidosis, and have acute complications such as gastrointestinal bleeding and uremic encephalopathy caused by uremia, require immediate emergency dialysis.

4. Hemodialysis treatment: For patients with uremia who come to the hospital for the first time, continuous renal replacement therapy should be performed immediately, and the original dialysis hospital should be asked for relevant information about dialysis patients (especially information about hepatitis B virus, hepatitis C virus, human acquired immunodeficiency virus, syphilis, etc.). After the patient's virus information is clarified, ordinary hemodialysis or continuous renal replacement therapy can be selected according to the patient's specific situation.

5. Treatment of chronic complications in maintenance dialysis patients: (1) For chronic complications in maintenance dialysis patients, such as hypertension, cardiovascular disease, anemia, water and electrolyte acid-base imbalance, infection, etc., active treatment is required according to relevant guidelines. (2) For patients who have not been on dialysis for a long time, special attention should be paid. It is recommended to use proton pump inhibitors and gastric mucosal protectants to protect the stomach and prevent gastrointestinal bleeding. (3) For patients with uremic complications (such as hyperkalemia, metabolic acidosis, heart failure, gastrointestinal bleeding, etc.), refer to the relevant guidelines for treatment.

III. Treatment of COVID-19 infection in patients with renal insufficiency

For maintenance hemodialysis patients infected with COVID-19, it is most important to maintain regular dialysis, and patients should be treated in accordance with the "Diagnosis and Treatment Plan for New Coronavirus Pneumonia (Trial Ninth Edition)". Maintenance hemodialysis patients have not been vaccinated with the COVID-19 vaccine and are a high-risk group for critical COVID-19. In clinical management, in addition to conventional treatment strategies such as oxygen therapy, high-flow nasal oxygen therapy, recombinant human granulocyte macrophage stimulating factor, thymosin, immunoglobulin G and other supportive treatments, it is also necessary to closely observe changes in the patient's condition, including the following:

(1) Closely monitor the SARS-CoV-2 nucleic acid circulation threshold, oxygenation index, lymphocyte count, D-dimer, chest CT images, etc.

(2) For patients without pulmonary infiltration at admission, chest imaging should be repeated 3 to 5 days later.

(3) If the patient's chest imaging features support the symptoms of COVID-19 upon admission, the patient should be treated immediately in the prone position (>16 h/d), and a chest CT scan should be repeated within 72 hours to determine whether the pulmonary exudate has progressed. If so, short-term glucocorticoids, convalescent plasma, COVID-19-specific human immunoglobulin, etc. can be given according to the patient's condition.

(4) Pay attention to the patient's nutritional treatment, ensure the patient's daily energy supply, actively prevent and treat complications, and prevent secondary bacterial or fungal infections. If the patient's condition worsens, he or she should be transferred to the ICU in time for further organ function support treatment.

(5) Given that patients are prone to hypercoagulable state after being infected with COVID-19, it is recommended that in addition to routine hemodialysis anticoagulation, a small dose of low molecular weight heparin be added on non-dialysis days for anticoagulation, and the bleeding tendency should be closely observed.

In addition, it is important for mild hemodialysis patients to prepare their own medications, which can be recommended clinically. Commonly used medications are mainly divided into the following categories, as shown in Figure 1.

Figure 1 Commonly used drugs for mild hemodialysis patients

References:

[1] COVID-19 diagnosis and treatment expert group of Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine. Treatment of novel coronavirus Omicron variant infection combined with severe underlying diseases[J]. Diagnostics Theory and Practice, 2022, 21(02):105-117.