Quick Guide to Treating Critically Ill Patients Infected with COVID-19 (First Edition)

1. Introduction: COVID-19 is a highly contagious disease that spreads rapidly and poses a great threat to human survival. Since it spreads regardless of race, age, or gender, it is likely to infect all of humanity. Based on the experience of fighting the epidemic over the past three years, it is known that the proportion of critically ill patients in the elderly is much higher than that in other age groups, but this does not mean that there are no critically ill patients in other age groups. The number of infections has soared after the recent relaxation of national control policies. Although according to expert opinions, the percentage of critically ill patients in the number of infected people is very low, the absolute number of critically ill patients should not be underestimated because the total number of infections is close to half of China's total population. Given that among the known critically ill patients, most of the deaths are elderly people, and most of them are accompanied by various underlying diseases; and the virus mainly damages the lungs, as well as important organs such as the kidneys, heart, and brain; and the terminal direct death is manifested by severe damage to lung function (commonly known as "white lungs"), the focus of treatment should be on dealing with lung damage.

After more than 70 years of development, the discipline of anesthesiology in China has developed into a high-quality professional team of more than 100,000 people. In the daily work of the Department of Anesthesiology, anesthesiologists perform anesthesia, endotracheal intubation, various vascular puncture and catheterization operations every day. In addition, during the operation, they must deal with the blood loss (even heavy blood loss), nerve reflexes and bone cement filling, amniotic fluid embolism, etc. caused by the operation at any time. Pulmonary embolism and cardiac arrest, so they have accumulated rich clinical experience in rescuing critically ill patients, especially those with lung injury. The Department of Critical Care Medicine was established in the process of the development of the discipline of anesthesia on the basis of the Critical Care Group of the Anesthesiology Branch of the Chinese Medical Association cultivated by the discipline of anesthesia. Therefore, anesthesiologists themselves have the qualifications, proficient skills and rich clinical experience to rescue critically ill patients. In the document approved by the Ministry of Health to establish the Department of Critical Care Medicine, it is particularly emphasized that the members of the Department of Critical Care Medicine should have work experience in the Department of Anesthesiology. In the early days of the development of anesthesia, Professor Wang Yuanchang, director of the Department of Anesthesiology at Tianjin University General Hospital, pioneered the use of external cardiac compression (then called external massage) in 1953 to successfully rescue three patients with cardiac arrest during anesthesia surgery, creating a precedent for cardiopulmonary resuscitation in China. In 1962, Professor Li Dexin, director of the Department of Anesthesiology at the Nanjing Military Region General Hospital, focused on the problem of brain dysfunction after cardiopulmonary resuscitation and focused on brain resuscitation. He successfully rescued dozens of patients with cardiac arrest caused by various reasons through comprehensive treatment methods such as systemic hypothermia plus local deep hypothermia of the brain, high-dose glucocorticoids to protect brain cell membranes, high-dose dehydration to treat refractory cerebral edema, and early hyperbaric oxygen. All of these constitute the unique professional ability of anesthesiologists, that is: in addition to daily anesthesia work, the clinical ability of anesthesiologists, which is different from any other department of doctors, is the rescue of critically ill patients.

In the fight against the COVID-19 pandemic in 2020, it was precisely because of the adoption of specific suggestions put forward by an anesthesiologist (the author myself) that the intubation suicide squad (later called the intubation commando), which was mainly composed of anesthesiologists, completed the rescue tasks of a large number of critically ill patients, and completely reversed the passive situation of a large number of critically ill patients dying in the ICU in the early stage.

The above brief introduction to the work of the Department of Anesthesiology fully proves that the Chinese anesthesiologist team is a well-trained, well-equipped, theoretically sound, skilled, and experienced rescue team. It is a team that can fight tough battles and win battles. In the face of a major epidemic and many critically ill patients in urgent need of rescue, we should use our strength, ability, and rescue level to help the country solve problems and save lives for patients.

2. Pathophysiological mechanisms of critically ill patients infected with COVID-19

In order to treat patients more effectively, it is necessary to first briefly discuss the pathophysiological mechanisms of patients infected with the new coronavirus.

1. Early clinical manifestations of patients infected with COVID-19

In the early days of the Wuhan outbreak in 2020, the news media reported a very important patient symptom, that is, the early subjective symptoms of the patients were not obvious, only slight fatigue, exhaustion, low fever, cough, etc. Most citizens were still living a normal life. It was only after the disease progressed that a large number of patients flocked to the hospital, and most of the patients underwent CT scans, only to find that a large number of patients had developed "ground glass opacity (GGO) in the lungs", that is, a large amount of fluid was filled in the interstitial tissue of the lungs, forming the so-called "white lungs". This manifestation is usually a late manifestation of severe infection in the ICU, but it appeared in the early stage of COVID-19 infection, which should be given enough attention. Unfortunately, due to lack of experience and clinical sensitivity, our experts and attending physicians did not respond as they should.

2. Early death of COVID-19 infected patients

Still based on the data from 2020, due to the lack of knowledge and clinical experience of the disease, as well as the concentrated emergence of a large number of patients, a run on medical resources occurred, resulting in early deaths of a considerable number of patients. Even when the Party Central Committee decided to close the city and the entire army sent a large number of medical personnel to support Wuhan City and Hubei Province, due to the lack of treatment experience and the lack of literature to learn from, early rescue in the ICU still failed to achieve satisfactory results. According to statistics on the number of deaths, the total number of deaths in Wuhan and Hubei is about 5,000, and the success rate of early ICU rescue accounts for only about 20% of the total number of critically ill patients.

3. Autopsy report of early deaths of patients infected with COVID-19

According to the limited and extremely rare autopsy reports, the most characteristic finding is that the lung interstitium is full of "jelly-like" substances. What is "jelly-like"? It is the performance of plasma protein drying up (protein denaturation and coagulation) when it is about to dry up. The importance of this result provides a very important diagnostic clue for the clinic, that is, the lung interstitial fluid of patients infected with the new coronavirus is not pure water, but plasma. This shows that in the early stage of the new coronavirus infection, the integrity of the pulmonary capillaries has been destroyed, and a large amount of plasma leaked into the lung interstitium, causing the occurrence of "white lung".

4. Causes and mechanisms of pulmonary capillary network destruction

In the current literature, there is no discussion on the causes of capillary network destruction, and it is difficult to explain it simply by the virus attacking alveolar cells and endothelial cells of the pulmonary capillary network. Based on the structure and physiological characteristics of the pulmonary circulation, the author tried to explain it from the perspective of fluid dynamics. Compared with the systemic circulation, the biggest feature of the pulmonary circulation is that its flow is consistent with the systemic circulation, but the pressure is very different. The normal value of arterial blood pressure is usually around 110/70mmHg, while the pulmonary artery pressure is only 25/12mmHg, and the central venous pressure is only 4-8 cm of water column. Based on such a structure, when the lung tissue comes into contact with the new coronavirus, its first reaction is sympathetic nerve excitement (note that it is not an immune mechanism. The first reaction of the human body to any strong external stimulation is sympathetic excitement. If the stimulation persists, it will trigger the so-called long feedback mechanism, leading to the immune system response), and strongly contract the pulmonary capillaries to prevent the virus from invading the body. This is the basic protection mechanism of the human body after thousands of years of evolution. Due to the continuous stimulation of the new coronavirus, the pulmonary capillary network continues to contract, the pulmonary circulation pressure increases sharply, and eventually the pulmonary capillary endothelial connection breaks, causing a large amount of plasma to leak into the pulmonary interstitium, resulting in the so-called "white lung". In addition, the continuous excitement of the sympathetic nerves at the level of the pulmonary capillaries can be understood as a "sympathetic storm" at the level of the pulmonary capillaries; and the sympathetic nerve excitement is achieved by releasing catecholamines in the vesicles, and then the vesicles re-uptake catecholamines to maintain the sympathetic nerve excitement. Since this process requires energy consumption, patients will feel tired, exhausted and have a high fever. If this pathological process cannot be blocked in time, the patient will eventually die from severe acidemia caused by severe hypoxia and gradual accumulation of carbon dioxide. This also explains why a large number of patients still died in the early stage under high-flow oxygen therapy. This explanation also provides sufficient reason for patients infected with the new coronavirus to pay attention to nutritional supplements.

3. Anesthesiology treatment plan for critically ill patients infected with COVID-19

01 Basic Principles

In the early stages of treatment, full anesthesia and full muscle relaxation are required, that is, through anesthesia, the patient's vital signs are completely controlled to the level of "ideal anesthesia state".

1) Why is full anesthesia necessary? Full anesthesia refers to the rescue process before the condition is relieved, and general anesthesia must be implemented throughout the process. The reason is: if critically ill patients are always awake before they die, they will be under the influence of various negative emotions such as fear, anxiety, depression, and insomnia for a long time. Not to mention the potential adverse effects of these factors on the human body, the oxygen consumption alone will increase sharply, directly accelerating the patient's death. Moreover, the gas exchange function of the new coronavirus-infected patients has declined due to severe lung damage, so it is easy to understand why the current rescue effect of the intensive care unit is not good. Once the patient is under anesthesia, all of the above negative effects will be blocked by anesthesia, and the body's metabolic rate will be reduced to the basal metabolic level. This alone can significantly improve the patient's oxygenation and create favorable conditions for the patient's recovery.

2) Why is muscle relaxation necessary throughout the entire process? Muscle relaxation throughout the entire process means that during the entire process of rescue under general anesthesia and endotracheal intubation, medium-acting or long-acting non-depolarizing muscle relaxants are used to maintain muscle relaxation. The benefits are: a. It facilitates the operation of endotracheal intubation. b. It helps to protect the safety of staff performing endotracheal intubation. Since muscle relaxants block the possibility of patients choking and coughing due to intubation, the possibility of infection is also avoided. c. It completely eliminates the asynchrony between the patient's spontaneous breathing and the ventilator, thereby improving the effectiveness of mechanical ventilation. This ventilation mode, in particular, is far more effective in extremely critically ill patients than the high-flow oxygen inhalation and non-invasive ventilators used in previous rescue operations. d. Under the action of muscle relaxants, the muscles of the whole body are completely relaxed, and their oxygen consumption is greatly reduced, which also helps to improve the patient's condition.

3) Why should patients be controlled in the "ideal state of anesthesia"? The "ideal state of anesthesia" theory is a theory of Chinese anesthesia proposed by the author in 1999. Its main content is to change the previous emphasis on the normality of blood pressure and heart rate to pay more attention to the regulation of microcirculation perfusion of various organs of the human body on the basis of normal blood pressure and heart rate. With the development of monitoring equipment, all physiological indicators that can be monitored clinically are controlled within the normal range of human physiology. In this way, there is no possibility of death of patients during anesthesia, and anesthesia can also provide a good internal environment for patients' postoperative recovery. If severe and extremely severe patients infected with the new coronavirus are controlled in a normal physiological state, the patients will avoid early death. It lays the foundation for the production of autoantibodies in patients. Because so far, there is no specific drug for the new coronavirus used in clinical practice, so as long as the patient can be guaranteed to survive the critical period, when the antibodies in his body are gradually produced, the patient can gradually recover.

02 Basic Workflow

1) After the patient enters the ICU, first establish vital sign monitoring, establish peripheral infusion access, and oxygen inhalation through mask. Draw venous blood supply to measure various basic parameters, including arteriovenous blood gas analysis values.

2) Anesthesia induction: Rapid induction is usually used, but the order of medication should be slightly changed:

a. Rocuronium bromide, which has the advantage of rapid onset of action.

b. For propofol-based therapies, it is recommended to perform endotracheal intubation 5 minutes after induction to ensure that the muscle relaxant takes full effect and the patient does not choke due to endotracheal intubation.

c. Fentanyl drugs are given intravenously after endotracheal intubation is completed. Because intravenous administration of fentanyl drugs can induce severe coughing in some patients, it is changed to be given after endotracheal intubation is completed.

3) Anesthesia maintenance:

a. It is recommended to use intravenous anesthetics to maintain.

b. It is recommended to use long-acting or medium- to long-acting muscle relaxants.

c. Long-acting opioid analgesics are recommended.

3) Endotracheal intubation: After induction, switch to artificial respiration with mask and oxygen, and start intubation after complete muscle relaxation. It is recommended to use a visual laryngoscope to ensure successful intubation at one time. Because the catheter is expected to be in place for a long time, it is recommended to use an endotracheal tube reinforced with steel wire. It is recommended to use a catheter number that is one size smaller than the number recommended in the usual textbook, that is, 7.0#~7.5# for men and 6.5#~7.0# for women. Connect the ventilator and start mechanical ventilation.

4) Initial parameters of the ventilator: respiratory rate RR: 12 times/minute, inspiration-expiration ratio I:E: 1:2, tidal volume Vt: 350ml/time,

Positive end-expiratory pressure PEEP: 0~2 mmHg, inspired oxygen concentration iO2: 0.5. If the patient's oxygen saturation is lower than 90%, iO2 can be used briefly starting from 1.0, and iO2 can be gradually reduced when the oxygen saturation rises to >90%.

5) Establish invasive hemodynamic monitoring: a. Puncture and catheterize the radial artery to measure direct arterial pressure. The left radial artery is usually selected, but left-handed people should choose the right hand. Alan's test should be performed before puncture, and other sites should be selected if the result is negative. b. Central venous catheterization: The Department of Anesthesiology usually chooses puncture through the right internal jugular vein, taking the advantages of simple operation, low complication rate, and convenient catheter insertion. Other departments and nursing departments usually choose right subclavian vein puncture or left cubital median vein, taking the advantages of greater patient comfort, but the incidence of puncture complications is slightly higher. After successful puncture, it is recommended to insert a 2- or 3-lumen central venous catheter to facilitate the input of various therapeutic drugs. If conditions permit, a floating catheter with a probe for continuous monitoring of cardiac output and venous oxygen saturation can be inserted, which can provide more hemodynamic parameters and venous oxygen saturation parameters, which is conducive to the judgment of the condition of critically ill patients.

6) After the patient's condition stabilizes, a gastric tube and a urinary catheter are inserted to provide gastrointestinal nutrition and retain urine. In principle, the gastrointestinal nutrition solution should be guaranteed to be 2500~3000 calories/day. This is extremely important for patients. Urine output is usually maintained at 80~100ml/hour.

7) After all operations are completed, measure the basic values ​​of various parameters as basic control values.

8) Regulate pulmonary capillary resistance and dredge pulmonary microcirculation: Under the monitoring of pulmonary artery pressure, a. lidocaine, b. propofol, c. phentolamine, or d. scopolamine can be continuously infused through an infusion pump. The principle is to reduce pulmonary artery pressure without affecting aortic pressure. At the beginning of infusion, it is also necessary to pay attention to the fact that as pulmonary blood flow increases, the pulmonary ventilation perfusion ratio changes, resulting in a transient decrease in blood oxygen saturation, which can be improved by temporarily stopping the drug.

9) Fluid therapy: Determine the daily fluid intake based on the patient's weight and water load. The general principle should be slightly relaxed unless the patient has chronic renal insufficiency. For patients with diabetes, the use of sugar water should be carried out under blood sugar monitoring.

10) Antibiotic treatment: Whether to use antibiotics depends on whether the patient has a bacterial infection. Usually, there is no thick sputum in a simple viral infection. However, the resistance of virally infected people is often reduced, and most patients will have multiple bacterial infections. Broad-spectrum antibiotics can be selected at the beginning, and sensitive antibiotics can be selected for treatment based on the results of bacterial culture. Antibiotics should be used in sufficient quantities to avoid insufficient dosage due to various side effects, turning treatment into a process of cultivating bacterial resistance. The sign of effective antibiotic treatment is that the patient's body temperature returns to normal and the sputum is significantly reduced until it disappears. The patient's mental state is significantly improved.

11) Other special examinations: a. Arteriovenous blood gas analysis, once in the morning and once in the afternoon. C-arm chest radiograph, once a day.

12) Is prone ventilation necessary? It should not be used when the patient is in critical condition, hemodynamic parameters are unstable, and blood oxygen saturation is significantly lower than normal.

13) When can the endotracheal tube be removed and replaced with spontaneous breathing? a. When the condition has improved significantly, iO2 has dropped to 0.3, oxygen saturation > 94%, and the C-arm machine shows that the white lung area has decreased significantly, you can try to change the anesthetic to a sedative while intubating, and stop using muscle relaxants. Under the condition of spontaneous breathing, if the patient's spontaneous breathing rate is <16 times/minute and the oxygen saturation is > 94%, you can consider removing the endotracheal tube. When removing the tube, you should be prepared for re-intubation, and have a laryngeal mask, a ball for artificial respiration, anesthesia induction drugs, and muscle relaxants ready.

IV. Nursing points for critically ill patients

1. Sputum suction: It is the focus of nursing care for critically ill patients. Gentle movements are required to avoid repeatedly moving the suction tube in and out. The suction tube should be slowly inserted into the deep part of the airway, and then the sputum should be suctioned and the catheter should be withdrawn while suctioning. Each time the sputum is extracted, it should be sent for cell culture and drug sensitivity testing. It is not appropriate to issue a fixed-time doctor's order for sputum suction, but suction should be performed in time when obvious sputum sounds are heard. For those who have been intubated for more than three days, special attention should be paid to observe whether there is a possibility of sputum forming dryness and blocking the catheter through suction. The doctor should be reminded in time to change the catheter.

2. Bedsore care: Follow the routine operation. However, if the patient needs to breathe in the prone position, this operation can be combined with it, and the patient's back can be fully massaged in the prone position. In the prone position, attention should be paid to the protection of the skin on the face and other bone protrusions.

3. Cleansing enema: It is an important part of the treatment and care of critically ill patients, which helps to reduce the transfer of pathogenic bacteria in the intestine. It is usually performed on the day of admission to the ICU, after all treatments are basically completed. It can be performed every 2 to 3 days thereafter.

4. Basic care in the morning and evening: The skin is the first barrier of the human body. Basic care every day, washing the patient's face and feet, and wiping the patient's body with hot water towels, is extremely important for the recovery of critically ill patients and should not be ignored. Especially in the process of washing the face and feet, it is more beneficial to supplement it with a short massage.

Due to time constraints, this guideline must have many deficiencies or omissions in its content. We hope that anesthesia colleagues from all regions will combine their own clinical experience and promptly propose revisions during clinical use so that they can be updated at any time and a new version can be launched to better guide the treatment of severe COVID-19 patients. During the writing of this guideline, Professor Xue Fushan, Director of the Department of Anesthesiology at Beijing Friendship Hospital, provided important clinical experience and good suggestions. I would like to express my sincere gratitude. This guideline refers to the treatment guidelines of the National Health Commission, the treatment guidelines of the Respiratory Critical Care Department of Peking Union Medical College Hospital, and the guidelines for perioperative treatment of COVID-19 patients edited by Professor Huang Yuguang of Peking Union Medical College Hospital. I would like to express my gratitude here.

Yu Buwei

Drafted in Shanghai on Tuesday, January 3, 2023

Expert Profile
Professor Yu Buwei <br /> Vice President of China Medical Education Association

Director of the Chinese Medical Association, Director of the Chinese Medical Doctor Association, President of the Anesthesiology Branch of the Chinese Medical Doctor Association

Lifelong professor and chief physician at Ruijin Hospital affiliated to Shanghai Jiaotong University School of Medicine

Director of Shanghai Medical Association, Executive Director of Shanghai Medical Association, President of Anesthesiologists Branch of Shanghai Medical Association

Editor-in-Chief of Clinical Anesthesiology

Honorary member of the Japanese Society of Anesthesiology