Overview
Clinical syndrome caused by the inability of the body’s oxygen supply and carbon dioxide discharge to meet metabolic needs, mainly manifested as dyspnea, cyanosis, etc. The etiology of the disease is related to airway obstructive lesions, lung tissue lesions, thoracic and pleural lesions, etc. The treatment includes general treatment, drug treatment, etc.
Definition of respiratory failure
Respiratory failure is a syndrome characterized by severe impairment of pulmonary ventilation and/or ventilatory function caused by various reasons, so that adequate gas exchange cannot be maintained at rest, thus causing a series of pathophysiological changes and corresponding clinical manifestations.
Classification
Classification according to the urgency of onset
Acute respiratory failure: severe impairment of pulmonary ventilation and/or gas exchange within minutes or hours, which can be life-threatening if not rescued in time.
Chronic Respiratory Failure: The impairment of respiratory function gradually worsens due to chronic diseases of the respiratory and neuromuscular systems, and develops into respiratory failure after a few days or more.
Classification by arterial blood gas
Type I Respiratory Failure: i.e. hypoxic respiratory failure, blood gas analysis is characterized by arterial partial pressure of oxygen (PaO2) <60mmHg, and arterial partial pressure of carbon dioxide (PaCO2) is reduced or normal.
Type II respiratory failure: i.e., hypercapnic respiratory failure, blood gas analysis is characterized by PaO2 <60 mmHg, accompanied by PaCO2 >50 mmHg.
Classification by pathogenesis
Pump failure: caused by dysfunction of the respiratory pump (the nerves, muscles and thorax that drive or constrain respiratory movements), with type II respiratory failure as the main manifestation.
Lung failure: caused by lung tissue and pulmonary vascular pathology or airway obstruction, may manifest type I or type II respiratory failure.
Morbidity
There are no authoritative epidemiological statistics in China.
Prevalent in the presence of respiratory system diseases, cardiovascular disease.
Causes
Causes
Obstructive lesions of the airways
Airway obstruction can be caused by inflammation, spasm, tumors, foreign bodies, fibrotic scarring of the trachea and bronchial tubes.
For example, chronic obstructive pulmonary disease (COPD) and severe asthma can cause airway spasm, inflammatory edema, secretion obstruction of airways, etc., which may lead to hypoxia and/or CO2 retention, or even respiratory failure.
Lung tissue lesions
Such as severe pneumonia, pulmonary edema, emphysema and other lung diseases.
Pulmonary vascular diseases
Pulmonary embolism, pulmonary vasculitis, multiple microthrombosis, etc.
Thoracic and pleural lesions
It can limit lung expansion and thoracic movement, leading to reduced ventilation, inhaled gas inhalation, affecting the function of gas exchange, and thus respiratory failure.
For example, flail chest due to chest trauma, thoracic deformity, severe spontaneous or traumatic pneumothorax, and massive pleural effusion.
Heart disease
Can lead to ventilation and gas exchange dysfunction, which can result in hypoxia and/or CO2 retention.
Examples include various ischemic heart diseases, cardiomyopathy, severe heart valve disease, pericardial disease, etc.
Neuromuscular diseases
Cerebrovascular disease, craniocerebral trauma, encephalitis, and sedative-hypnotic intoxication can directly or indirectly inhibit the respiratory center.
Injury to the cervical or high thoracic segments of the spinal cord (tumor or trauma), poliomyelitis, polyneuritis, myasthenia gravis, organophosphorus poisoning, tetanus, and severe disorders of potassium metabolism can involve the respiratory muscles, resulting in respiratory muscle weakness or paralysis, leading to respiratory failure.
Pathogenesis
Various etiologic factors cause respiratory failure through five main mechanisms: insufficient pulmonary ventilation, diffusion impairment, ventilation/blood flow ratio imbalance, increased arterio-venous anatomical shunts within the lungs, and increased oxygen consumption, resulting in impaired pulmonary ventilation and/or gas exchange processes.
Respiratory failure caused by a single mechanism is rare in clinical practice, and often multiple mechanisms coexist or are involved sequentially as the disease progresses.
Symptoms
Main Symptoms
Dyspnea
Acute respiratory failure is characterized by increased respiratory rate in the early stages. In severe cases, dyspnea occurs with increased activity of the accessory respiratory muscles and simultaneous depression of the supraclavicular fossa, the suprasternal fossa, and the intercostal space during inspiration.
Chronic respiratory failure is characterized by labored breathing with prolonged expiration, and shallow and rapid breathing in severe cases. If CO2 retention is complicating, arterial blood carbon dioxide partial pressure rises too quickly or significantly so that CO2 anesthesia occurs, shallow and slow respiration or tidal respiration may occur.
Cyanosis
Cyanosis of lips, fingers (toes), nail beds and other parts of the body is a typical manifestation of hypoxia.
Cyanosis is usually not obvious in anemic patients.
Other symptoms
Psycho-neurological symptoms
Acute respiratory failure may rapidly appear mental disorder, mania, coma, convulsions and other symptoms.
In chronic respiratory failure, with the rise of PaCO2, there will be excitatory symptoms such as restlessness, day and night, and then there will be inhibitory symptoms such as indifference, muscle tremor, intermittent convulsions, drowsiness, and even coma.
Circulatory symptoms
Tachycardia is mostly seen.
Severe hypoxia and acidosis may cause blood pressure drop, arrhythmia and even cardiac arrest.
Those with CO2 retention may have filling of body surface veins, red skin, warm and sweaty, elevated blood pressure, throbbing headache and so on.
Digestive system symptoms
It may cause upper gastrointestinal bleeding with symptoms such as vomiting blood, black stools and dizziness.
Urinary system symptoms
Large amounts of non-dissolving foam in the urine.
Decreased urine output occurs in complication with pulmonary heart disease.
Complications
Infection
Caused by secondary immunocompromise, impaired lung clearance, placement of catheters (tracheal intubation, urinary catheters, intravenous tubes, etc.) and contamination of other instruments.
Pneumonia, sepsis, and urinary tract infections are most common.
Renal Failure
Acute renal failure can occur in those with acute respiratory failure, with multi-system symptoms such as oliguria or anuria, generalized edema, nausea, and vomiting.
Pulmonary encephalopathy
The main manifestations are indifference, muscle tremor or fluttering tremor, intermittent convulsions, lethargy or even coma.
Consultation
Department of Medicine
Emergency Department
If symptoms such as severe respiratory distress, cyanosis, mental disorders, or coma occur, it is recommended to consult the Emergency Department immediately.
Respiratory Medicine
Difficulty in breathing, prolonged expiration, shallow breathing, etc., we recommend prompt medical attention.
Preparation
Consultation: Registration, Preparation of documents, Frequently Asked Questions
Tips for medical treatment
Chest X-rays or chest CT are often needed, so avoid wearing clothing made of metal, and inform your doctor if you are pregnant or planning to become pregnant.
Preparation Checklist
Symptom list
Pay particular attention to the time of onset of symptoms, special symptoms, etc.
Is there dyspnea, difficulty in breathing?
Is there cyanosis, e.g., blue-purple color of lips and skin?
Is there irritability, or apathy, convulsions, drowsiness, etc.?
Is there a large amount of non-dissolving foam in the urine?
Is there vomiting of blood or black stools?
Medical History Checklist
Are there any respiratory diseases such as COPD, asthma, pneumonia, pulmonary edema, etc.?
Has there been any chest trauma?
Any cardiomyopathy, heart valve disease, pericardial disease, etc.?
Checklist
Test results in the last six months, which can be brought to the doctor’s office
Laboratory Tests: blood test, urine test, arterial blood gas analysis
Imaging tests: chest X-ray, chest CT, echocardiography, cardiac ultrasound
Specialized tests: lung function test, fiberoptic bronchoscopy
Medication list
Medication in the last 3 months, if there is a box or package, you can bring it with you to the doctor’s office
Bronchodilators: salbutamol, ipratropium bromide, aminophylline
Respiratory stimulants: Doxapram hydrochloride
Others: potassium chloride, levofloxacin, azithromycin
Diagnosis
Diagnosis is based on
Medical history
History of respiratory or other systemic diseases.
History of chest trauma or surgery.
Clinical manifestations
Symptoms
Symptoms such as dyspnea, cyanosis, mental disorganization, and coma are present.
Physical examination
Physical examination reveals the “three concave signs”, i.e., concavity of the supraclavicular fossa, suprasternal fossa, and intercostal space occurring at the same time during inhalation.
Increased pulse rate and irregular pulse beat may be seen.
Laboratory Tests
Arterial Blood Gas Analysis
It mainly detects different types of gases and acid-base substances in arterial blood, which helps to determine the patient’s oxygenation and acid-base balance.
Type I respiratory failure: PaO2 <60mmHg, PaCO2 reduced or normal.
Type II respiratory failure: PaO2 <60 mmHg with PaCO2 >50 mmHg.
Compensated respiratory acidosis: elevated PaCO2 and normal pH.
Uncompensated respiratory acidosis: elevated PaCO2, pH <7.35.
Oxygenation index (PaO2/FiO2) can be calculated based on the ratio of PaO2 to inspired oxygen concentration (FiO2), which can help to quickly assess the severity of respiratory failure and guide treatment.
Routine blood tests
To find out the changes of blood cells (red blood cells, white blood cells, platelets), hemoglobin and so on.
Elevated white blood cells and neutrophils may be seen.
Fasting is not required before the test.
Urine routine
In the presence of kidney damage, abnormal red blood cells may be present in the urine and there may be an abnormal increase in urine protein.
Liver and Kidney Function
To understand the state of liver and kidney function, and to determine the damage of liver and kidney function.
When renal function is impaired, creatinine and urea nitrogen may be elevated.
When liver function is impaired, aminotransferases are elevated, and bilirubin may also be elevated.
Fasting is required before the test.
Imaging
Chest X-ray / Chest CT: It can detect lesions in the lung structures and help the doctor to determine the primary disease.
Radionuclide lung ventilation/perfusion scan: helps to analyze the cause of respiratory failure.
Echocardiogram: Helps to examine the structure and function of the heart.
Specialized tests
Lung function test: To determine the nature of ventilation dysfunction (obstructive, restrictive or mixed) and whether it is combined with ventilation dysfunction, and to judge the severity of ventilation and ventilation dysfunction through lung function.
Fiberoptic bronchoscopy: It is important for clarifying airway disease and obtaining pathological evidence.
Differential diagnosis
The clinical manifestations of respiratory failure are complex and varied, and doctors will differentiate it from other corresponding diseases according to different clinical manifestations.
Bronchial asthma
Similarities: both have dyspnea.
Differences: Bronchial asthma is typically characterized by episodes of expiratory dyspnea with rales. Symptoms may occur within minutes and last for hours to days, and may be relieved by the use of asthma medications or may resolve spontaneously.
Pneumothorax
Similarities: Both have chest tightness and dyspnea.
Differences: Pneumothorax is often triggered by chest injury, lung disease, mechanical ventilation, etc. The typical symptoms are sudden onset of unilateral chest pain. Typical symptoms are sudden onset of unilateral chest pain, which is often pinprick-like or knife-like and lasts for a short period of time, followed by symptoms such as chest tightness and dyspnea, and may be accompanied by irritating cough.
Left heart failure
Similarities: both have dyspnea.
Differences: Left heart failure is mainly caused by abnormal structural function of the heart and compensatory insufficiency. It may be manifested as progressive exertional dyspnea, nocturnal paroxysmal dyspnea, sedentary respiration, coughing, etc., and hemoptysis in a few cases.
Pulmonary embolism
Similarity: both have chest tightness and dyspnea.
Differences: Dyspnea in pulmonary embolism is obvious after activity, and angina-like pain, tachycardia, and even shock may occur.
Treatment
Treatment principle
The principle of treatment for respiratory failure is to open the airway, correct hypoxia and improve ventilation, treat the original disease, and strengthen the monitoring and support of organ function.
General treatment
Oxygen therapy
Nasal catheter and mask oxygen are mostly used.
Type I respiratory failure needs to be given high concentration oxygen therapy to maintain oxygen saturation >92%. If hypoxemia cannot be corrected by oxygen therapy, continuous positive airway pressure ventilation (CPAP) needs to be considered either non-invasively or invasively.
Type II respiratory failure should be treated with controlled oxygen therapy and CO2 needs to be monitored and non-invasive or invasive ventilation is required if necessary.
Chronic respiratory failure can be treated with long-term home oxygen therapy (> 15 hours/day) under medical supervision, which can significantly improve quality of life.
Do not self-adjust oxygen flow.
Nutritional support
The patient is in a high metabolic state and adequate nutrition should be ensured.
For critically ill type patients who cannot eat normally by mouth, a nasogastric tube or nasojejunal tube can be placed.
The specific nutritional program should be formulated according to the general condition of the body, access, hepatic and renal function, and glucose and lipid metabolism.
Rest
Bed rest, close monitoring of respiration, heart rate, blood pressure, blood oxygen saturation, etc., in order to understand the condition and the effect of treatment.
Those who have been lying down for a long time should be given regular turning, back patting and sputum suction to keep the airway open.
Active treatment of primary disease
Congenital heart disease heart failure pulmonary edema caused by respiratory failure, should be used cardiac drugs and diuretics.
For persistent asthma, apply anti-inflammatory, release airway spasm and other measures.
For pulmonary infection, choose reasonable anti-infective treatment, etc.
Acute phase treatment
If the patient becomes unconscious, he should be put in the supine position, with the head tilted back, the jaw lifted and the mouth opened, and the secretions and foreign bodies in the airway should be removed.
An artificial airway should be established if necessary. Oropharyngeal airway, nasopharyngeal airway and laryngeal mask are usually applied when the condition is critical and intubation is not available, and then tracheal intubation or tracheotomy is performed when the condition permits.
Medication
Respiratory stimulants
Doxapram hydrochloride is mostly applied to respiratory failure caused by central inhibition and insufficient ventilation, and should not be used in respiratory failure caused by lung ventilation dysfunction.
It needs to be applied when the respiratory muscle function is basically normal and the airway is patent, otherwise it will promote respiratory muscle fatigue and aggravate CO2 retention.
Use with caution in cases of frequent convulsions due to uncorrected cerebral hypoxia and cerebral edema.
Do not stop the drug suddenly.
Bronchodilators
Can relax the bronchial smooth muscle, dilate the bronchial tubes, relieve airflow limitation.
Generally, β2-adrenergic agonists (salbutamol, formoterol, etc.), anticholinergics (ipratropium bromide, etc.), theophyllines (aminophylline, dihydroxypropyl theophylline), etc. are used.
Acute respiratory failure is mainly administered intravenously.
Drugs to correct acid-base balance imbalance
In correcting respiratory acidosis due to CO2 retention, the administration of arginine hydrochloride and potassium chloride supplementation is usually considered to correct the underlying metabolic alkalosis.
Anti-infective drugs
Effective anti-infective drugs should be selected with reference to the results of sputum bacterial culture and drug sensitivity test under the condition of smooth drainage of respiratory secretions.
Quinolones (e.g., levofloxacin) or β-lactams (e.g., cephalosporins, penicillins) in combination with macrolides (e.g., erythromycin, azithromycin) may be used for drug therapy.
Special tips
During drug treatment, you should adhere to the doctor’s instructions strictly, do not change the dose of drugs without authorization or suddenly stop the drug, to ensure that the treatment plan is implemented.
Do not believe in folk remedies, secret prescriptions or self-medication.
Other treatments
Extracorporeal membrane oxygenation (ECMO)
A type of treatment in which the patient’s venous blood is drawn outside the body and then passed through an oxygenator for adequate gas exchange before being introduced into the body.
ECMO can partially or completely replace cardiopulmonary function, allowing the heart and lungs to fully rest, reducing the occurrence of ventilator-associated lung injury, and buying more time for the treatment of the original disease.
High-frequency ventilation
Mostly used in acute respiratory failure.
Using a significantly higher frequency than the number of physiologic breaths, ventilation at a very low tidal volume improves oxygenation with unaffected cardiac output and no increase in the incidence of air leaks.
Prognosis
Cure.
The outcome of chronic respiratory failure is related to the timing of treatment, the presence of complications, and the underlying physical condition. Early and standardized treatment generally reduces complications and improves prognosis.
If acute respiratory failure is not accompanied by serious underlying diseases, the prognosis is better after timely rescue. If it develops into respiratory distress syndrome, the risk of death increases.
If the patient himself has serious underlying diseases, he is prone to systemic multi-organ failure and has a poorer prognosis.
Hazards
Acute respiratory failure is a common critical illness in clinical practice, characterized by rapid change in condition and high mortality rate, easily leading to multiple organ function involvement, and in severe cases, life-threatening.
Chronic respiratory failure is recurrent and can affect normal work and life.
During the treatment of respiratory failure, if tracheal intubation is required, the intubation process may lead to tooth loss or damage to the mucous membrane of the mouth, nose and throat, causing bleeding or dislocation of the jaw joints.
Patients who apply mechanical ventilation for a long period of time are prone to develop ventilator-associated pneumonia.
Daily
Daily Management
Dietary management
Closely monitor the general condition of the body, access, liver and kidney function and glucose and lipid metabolism, etc., in order to formulate a specific nutritional supply program.
For those who can eat normally by mouth, it is advisable to eat small meals and chew slowly to avoid respiratory insufficiency due to excessive satiety.
If there is no cardiac or renal insufficiency, more water can be consumed in moderation to replenish the consumed water, dilute the sputum, and facilitate the discharge of sputum.
Life management
Rest
If the disease is severe, in order to reduce physical exertion and oxygen consumption, bed rest is required, and self-care activities and unnecessary operations should be minimized.
When breathing is laborious, try to adopt semi-recumbent position or sitting position, lying on the bed table to improve breathing.
Long-term bedridden people should have regular lower limb massage to prevent the formation of lower limb deep vein thrombosis.
Appropriate exercise
Appropriate activities and breathing exercises should be carried out under doctor’s supervision to help restore lung function.
Activities with high oxygen consumption should be avoided, and you can start with low-intensity activities such as walking according to your own situation.
Keep the airway open
For long-term bedridden patients, family members should turn the patient over once every one to two hours and perform back tapping to facilitate the expulsion of sputum.
Dorsal tapping should be done 2 hours after a meal to 30 minutes before a meal to avoid triggering vomiting which may lead to aspiration.
The percussionist bends the fingers of both hands together so that the palm side is in the shape of a cup, and percusses the chest wall from the bottom of the lungs from the bottom up, from the outside to the inside with wrist force, rapidly and rhythmically, percussing the chest wall for 1-3 minutes per lung lobe, and making an empty and deep tapping sound when percussing, which indicates a correct percussion maneuver.
The force of percussion should be moderate, so that the patient does not feel pain.
When percussion should pay close attention to the patient’s response.
Under the guidance of the doctor to learn effective breathing and coughing, coughing techniques, such as lip-constriction breathing, abdominal breathing and other methods, in order to delay the deterioration of lung function.
For those who need home oxygen therapy, patients and their families should understand its methods and precautions in detail.
If the sputum has a special smell or if there are changes in sputum volume, color and viscosity, the patient should contact the doctor in time so that the treatment plan can be adjusted.
Avoid cold stimulation
Pay attention to weather changes and increase clothing appropriately in cold weather.
Wear warm hats, masks, gloves and warm socks when going out.
Preventing Infections
Avoid going to places where people gather.
Smoking cessation
Strictly quit smoking and avoid exposure to second-hand smoke.
Psychological support
Tension and anxiety may arise due to difficulty in breathing, premonition of critical condition, and the possibility of life-threatening illness. The patient should face the disease with a positive and optimistic attitude and build up confidence in overcoming the disease.
Family members should give more psychological care to the patients. For patients who establish artificial airway and use mechanical ventilation, they can be encouraged to say or write out the factors that cause or aggravate anxiety.
Disease monitoring
Normally, attention should be paid to monitoring the respiratory rate, the presence of cyanosis, blood pressure, heart rate, sputum volume and character.
If symptoms worsen, or new symptoms appear, you must seek medical attention.
Follow the doctor’s prescribed schedule for follow-up appointments.
Prevention
Reasonable dietary arrangement, strengthen nutrition and improve physical condition.
Avoid inhaling irritating gases, quit smoking and avoid second-hand smoke.
Avoid contact with people with respiratory infections and minimize the chance of infection.
Avoid stimulation of adverse factors such as exertion and emotional stress.
Actively treat your underlying diseases.