Respiratory failure overview: Difference between revisions
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===Diagnostic Study of Choice=== | ===Diagnostic Study of Choice=== | ||
Respiratory failure is mainly diagnosed based on clinical presentation. There is no single diagnostic study of choice for the diagnosis of respiratory failure, but respiratory failure can be diagnosed based on history, examination and [[Arterial blood gas|arterial blood gases]]. | Respiratory failure is mainly diagnosed based on clinical presentation. There is no single diagnostic study of choice for the diagnosis of respiratory failure, but respiratory failure can be diagnosed based on history, examination and [[Arterial blood gas|arterial blood gases]]. | ||
===History and Symptoms=== | ===History and Symptoms=== | ||
A positive history of sudden onset of [[shortness of breath]], trauma to the neck or thorax and [[Altered mental state|change in mental status]] is suggestive of respiratory failure. Common symptoms of respiratory failure include [[tachypnea]] , [[stridor]] and [[dyspnea]]. Less common symptoms of respiratory failure include [[anxiety]], [[headache]], and [[asterixis]]. | |||
===Physical Examination=== | ===Physical Examination=== | ||
Patients with respiratory failure usually appear distressed with [[altered mental status]]. Physical examination of patients with respiratory failure is usually remarkable for [[dyspnea]], [[stridor]], and [[tachypnea]]. | |||
===Laboratory Findings=== | ===Laboratory Findings=== | ||
Laboratory findings consistent with the diagnosis of respiratory failure include abnormal [[bicarbonate]], [[oxygen]], [[phosphate]], and [[magnesium]] levels. | |||
===Chest X-ray=== | |||
X-ray may be helpful in establishing the etiology of respiratory failure as it may detect underlying disease. Findings on x-ray suggestive of pre-existing [[Chronic obstructive pulmonary disease|COPD]] include hyperinflation and a flattened diaphragm. X-ray findings suggestive of [[interstitial lung disease]] include reticular nodular shadows. Findings on x-ray suggestive of acute respiratory distress include [[cardiomegaly]], redistribution of vessels, [[peribronchial cuffing]], [[pleural effusion]], lines within the septum, and bat-wing distribution of perihilar infiltrates. Finally, thoracic cage abnormalities may be detected such as [[kyphosis]], [[scoliosis]], [[pectus excavatum]], fractured ribs and [[ankylosing spondylitis]], as well as [[diaphragmatic paralysis]]. | |||
===Electrocardiogram=== | ===Electrocardiogram=== | ||
An ECG may be helpful in detecting underlying [[cardiovascular disease]] and to diagnose [[Cardiac arrhythmia|arrhythmia]] arising as a complication of severe [[hypoxemia]] and [[acidosis]]. | |||
===CT scan=== | ===CT scan=== | ||
A CT scan may be helpful in establishing the etiology of respiratory failure as it may detect underlying disease. CT can also predict the incidence of respiratory failure after trauma to the spine. Findings on CT tend to be similar to those found on plain x-ray. Findings on CT scan suggestive of pre-existing [[Chronic obstructive pulmonary disease|COPD]] include hyperinflation and a flattened diaphragm. CT findings suggestive of [[interstitial lung disease]] include reticular nodular shadows. Findings on CT scan suggestive of acute respiratory distress include [[cardiomegaly]], redistribution of vessels, [[peribronchial cuffing]], [[pleural effusion]], lines within the septum, and bat-wing distribution of perihilar infiltrates. CT may also reveal pathology of the neck, brainstem and peripheral nervous system, such as [[stroke]], [[tumor]] and transection of the spinal cord. | |||
===MRI=== | ===MRI=== | ||
MRI may be helpful in establishing the etiology of respiratory failure, in particular if the cause is due to a pathology of the neck, central or peripheral nervous system. MRI can predict the occurence of respiratory failure in a patient with [[cervical spine injury]]. MRI may suggest that [[stroke]], [[tumor]], [[spinal cord injury]] and/or complete spinal transection are the cause of respiratory failure. Findings on MRI may include [[embolism]], [[thrombosis]], and [[haemorrhage]]. | |||
===Echocardiography and Ultrasound=== | |||
[[Echocardiography]] may be helpful in the diagnosis of a cardiac cause of respiratory failure. Findings on an [[echocardiography]] suggestive of cardiac cause of respiratory failure include [[Left ventricle enlargement|dilatation]] of the [[Dilated cardiomyopathy|left ventricle]], focal or global wall motion irregularities, severe [[mitral regurgitation]]. If patients show a normal size of their heart and a normal blood pressure then this suggests an etiology of [[Acute respiratory distress syndrome|acute respiratory distress]]. [[Echocardiography]] is also useful in patients with chronic hypercapnic respiratory failure as the function of the right ventricle and the pulmonary artery pressure may be monitored. Thoracic ultrasound is a part of critical care ultrasonography and may be helpful in the diagnosis of acute cardiopulmonary respiratory failure. Findings on an ultrasound suggestive of respiratory failure include the presence of [[pneumothorax]], alveolar and interstitial aeration abnormalities, and [[pleural effusion]]. | |||
===Other Imaging Findings=== | ===Other Imaging Findings=== | ||
There are no other imaging findings associated with respiratory failure. | |||
===Other Diagnostic Studies=== | ===Other Diagnostic Studies=== | ||
Despite most patients being unable to perform a [[Spirometry|pulmonary function test]] during acute respiratory failure, [[Spirometry|pulmonary function testing]] may be useful with chronic respiratory failure. Chronic respiratory failure is usually due to an underlying restrictive disease, [[Spirometry|pulmonary function test]] findings include a decrease in [[FEV1]] and a significant decrease in [[FVC]] with an overall increase in the [[FEV1/FVC ratio]]. It is unlikely that an [[obstructive lung disease]] would cause respiratory failure. In respiratory failure with significant cardiac function compromise, a right side [[cardiac catheter]] may be used. [[Catheter|Catheterization]] is controversially used to assess those patients with acute hypoxemic respiratory failure where cardiac function is uncertain. | |||
==Treatment== | ==Treatment== | ||
Revision as of 20:04, 20 March 2018
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: M. Khurram Afzal, MD [2]
Overview
Historical Perspective
The diagnostic and treatment strategies for respiratory failure and it's associated conditions have come a long way. Since the discovery of the stethoscope by René Laennec in 1816, to the work of Fenn and his team in 1946 on pulmonary gas exchange, the use of cuffed endotracheal tubes by Ibsen in 1954 to administer positive pressure ventilation to patients in respiratory failure who were admitted to the intensive care units, that became common in the United States in 1960.
Classification
Respiratory failure may be classified into several subtypes as follows; Type I, Type II, Type III, Type IV.
Pathophysiology
Causes
Common causes of respiratory failure include pneumonia, pulmonary edema, pulmonary embolism, acute respiratory distress syndrome, atelectasis, asthma, COPD, neuromuscular and chest wall disorders, inadequate post-operative analgesia, smoking, obesity and shock. Life-threatening causes of respiratory failure include chronic obstructive pulmonary disease, acute on chronic respiratory failure, pulmonary infection, pulmonary embolism, heart failure, cardiac arrhythmia and lung cancer.
Differentiating Respiratory Failure from other Diseases
Epidemiology and Demographics
The incidence of respiratory failure is approximately 137.1 per 100,000 individuals in the United States and the mortality rate is approximately 29%-42%. The incidence is higher among patients ≥ 65 years of age and the mortality rate is higher among African-Americans and Hispanics compared to Caucasians. Men and women are equally affected.
Risk Factors
- Common risk factors in the development of respiratory failure include smoking, alcohol abuse, COPD exacerbation, obesity.
Screening
Natural History, Complications, and Prognosis
Diagnosis
Diagnostic Study of Choice
Respiratory failure is mainly diagnosed based on clinical presentation. There is no single diagnostic study of choice for the diagnosis of respiratory failure, but respiratory failure can be diagnosed based on history, examination and arterial blood gases.
History and Symptoms
A positive history of sudden onset of shortness of breath, trauma to the neck or thorax and change in mental status is suggestive of respiratory failure. Common symptoms of respiratory failure include tachypnea , stridor and dyspnea. Less common symptoms of respiratory failure include anxiety, headache, and asterixis.
Physical Examination
Patients with respiratory failure usually appear distressed with altered mental status. Physical examination of patients with respiratory failure is usually remarkable for dyspnea, stridor, and tachypnea.
Laboratory Findings
Laboratory findings consistent with the diagnosis of respiratory failure include abnormal bicarbonate, oxygen, phosphate, and magnesium levels.
Chest X-ray
X-ray may be helpful in establishing the etiology of respiratory failure as it may detect underlying disease. Findings on x-ray suggestive of pre-existing COPD include hyperinflation and a flattened diaphragm. X-ray findings suggestive of interstitial lung disease include reticular nodular shadows. Findings on x-ray suggestive of acute respiratory distress include cardiomegaly, redistribution of vessels, peribronchial cuffing, pleural effusion, lines within the septum, and bat-wing distribution of perihilar infiltrates. Finally, thoracic cage abnormalities may be detected such as kyphosis, scoliosis, pectus excavatum, fractured ribs and ankylosing spondylitis, as well as diaphragmatic paralysis.
Electrocardiogram
An ECG may be helpful in detecting underlying cardiovascular disease and to diagnose arrhythmia arising as a complication of severe hypoxemia and acidosis.
CT scan
A CT scan may be helpful in establishing the etiology of respiratory failure as it may detect underlying disease. CT can also predict the incidence of respiratory failure after trauma to the spine. Findings on CT tend to be similar to those found on plain x-ray. Findings on CT scan suggestive of pre-existing COPD include hyperinflation and a flattened diaphragm. CT findings suggestive of interstitial lung disease include reticular nodular shadows. Findings on CT scan suggestive of acute respiratory distress include cardiomegaly, redistribution of vessels, peribronchial cuffing, pleural effusion, lines within the septum, and bat-wing distribution of perihilar infiltrates. CT may also reveal pathology of the neck, brainstem and peripheral nervous system, such as stroke, tumor and transection of the spinal cord.
MRI
MRI may be helpful in establishing the etiology of respiratory failure, in particular if the cause is due to a pathology of the neck, central or peripheral nervous system. MRI can predict the occurence of respiratory failure in a patient with cervical spine injury. MRI may suggest that stroke, tumor, spinal cord injury and/or complete spinal transection are the cause of respiratory failure. Findings on MRI may include embolism, thrombosis, and haemorrhage.
Echocardiography and Ultrasound
Echocardiography may be helpful in the diagnosis of a cardiac cause of respiratory failure. Findings on an echocardiography suggestive of cardiac cause of respiratory failure include dilatation of the left ventricle, focal or global wall motion irregularities, severe mitral regurgitation. If patients show a normal size of their heart and a normal blood pressure then this suggests an etiology of acute respiratory distress. Echocardiography is also useful in patients with chronic hypercapnic respiratory failure as the function of the right ventricle and the pulmonary artery pressure may be monitored. Thoracic ultrasound is a part of critical care ultrasonography and may be helpful in the diagnosis of acute cardiopulmonary respiratory failure. Findings on an ultrasound suggestive of respiratory failure include the presence of pneumothorax, alveolar and interstitial aeration abnormalities, and pleural effusion.
Other Imaging Findings
There are no other imaging findings associated with respiratory failure.
Other Diagnostic Studies
Despite most patients being unable to perform a pulmonary function test during acute respiratory failure, pulmonary function testing may be useful with chronic respiratory failure. Chronic respiratory failure is usually due to an underlying restrictive disease, pulmonary function test findings include a decrease in FEV1 and a significant decrease in FVC with an overall increase in the FEV1/FVC ratio. It is unlikely that an obstructive lung disease would cause respiratory failure. In respiratory failure with significant cardiac function compromise, a right side cardiac catheter may be used. Catheterization is controversially used to assess those patients with acute hypoxemic respiratory failure where cardiac function is uncertain.