Flail Chest

Overview

Definition

Flail chest is defined as 3 or more contiguous ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy that are fractured in 2 or more different locations, resulting in a freely moving segment of the chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy that is discontinuous from the rest of the thoracic cage.

Epidemtiology

• Seen in 7% of all chest trauma
• 60% of cases are associated with other injury (most commonly hemothorax Hemothorax A hemothorax is a collection of blood in the pleural cavity. Hemothorax most commonly occurs due to damage to the intercostal arteries or from a lung laceration following chest trauma. Hemothorax can also occur as a complication of disease, or hemothorax may be spontaneous or iatrogenic. Hemothorax, pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax, or head trauma Head trauma Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. Head Trauma)
• Risk factors:
  • Male gender Gender Gender Dysphoria
  • Intoxication

Etiology

• Motor vehicle accidents Motor Vehicle Accidents Spinal Cord Injuries (approximately 75%)
• Falls, particularly in the elderly (approximately 15%)
• Blunt trauma

Pathophysiology

• Significant traumatic force is applied to the chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy, creating multiple rib fractures.
• Disruption of structural components of the chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy (e.g., bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types, cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology, muscle) leads to free-floating segment of chest.
• During respiratory cycle, segments move paradoxically:
  • During inspiration Inspiration Ventilation: Mechanics of Breathing, segment moves inward (instead of outward) due to negative intrathoracic pressure → leading to ineffective ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing → hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage
  • During expiration Expiration Ventilation: Mechanics of Breathing, segment moves outward (instead of inward) due to positive intrathoracic pressure.
• Mechanical limitation of chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy motion affects the size of changes in thoracic volume and patient-generated tidal volume Tidal volume The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are tv or V with subscript t. Ventilation: Mechanics of Breathing → respiratory insufficiency

Diagnosis

Flail chest is a clinical diagnosis (confirmed by imaging) made by identifying the paradoxical movement of a chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy segment when the patient is spontaneously breathing. 

Symptoms

• Severe chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Shortness of breath Shortness of breath Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea

Signs

• Paradoxical chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy movement (disappears after intubation Intubation Peritonsillar Abscess with positive pressure ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing)
• Respiratory distress
• Tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination
• Hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome
• ↓ breath sounds during auscultation
• Chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy deformity Deformity Examination of the Upper Limbs and/or ecchymosis Ecchymosis Extravasation of blood into the skin, resulting in a nonelevated, rounded or irregular, blue or purplish patch, larger than a petechia. Orbital Fractures

Imaging

• Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests (less sensitive, but usually sufficient to confirm clinical suspicion) 
• CT scan (most sensitive)
• Findings include:
  • Multiple adjacent rib fractures
  • Fractures 1 + location

Management and Complications

Management

• Oxygen supplementation
• Adequate pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control:
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways impairs respiratory effort → hypoventilation, atelectasis Atelectasis Atelectasis is the partial or complete collapse of a part of the lung. Atelectasis is almost always a secondary phenomenon from conditions causing bronchial obstruction, external compression, surfactant deficiency, or scarring. Atelectasis, pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia, and respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure
  • Epidural infusion: preferred method for extensive rib fractures
  • Intercostal nerve blocks also used
• Intubation Intubation Peritonsillar Abscess with mechanical positive pressure ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing if respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure presents (improves ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing and ↓ paradoxical movement)
• Chest physiotherapy Physiotherapy Spinal Stenosis
• Monitor with serial chest X-rays X-rays X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. X-rays, arterial blood gasses, pulse oximetry, and capnography (to detect early signs of respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure).
• Treat associated conditions.
• Surgical fixation of ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy (not often used)

Complications

Pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax:

• Collapsed lung
• Signs and symptoms:
  • ↓ breath sounds on ipsilateral chest
  • Hyperresonance on percussion Percussion Act of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained. Pulmonary Examination
• Management:
  • Supplemental oxygen Supplemental Oxygen Respiratory Failure
  • Possible chest tube (large pneumothoraces)

Tension pneumothorax Tension Pneumothorax Pneumothorax:

• Pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax that is under pressure
• Signs and symptoms:
  • Tracheal deviation Tracheal Deviation Pneumothorax → mediastinal shift away from tension pneumothorax Tension Pneumothorax Pneumothorax
  • Distended neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
• Management: emergent needle decompression Needle Decompression Pneumothorax → chest tube placement Tube placement Surgical procedure involving the creation of an opening (stoma) into the chest cavity for drainage; used in the treatment of pleural effusion; pneumothorax; hemothorax; and empyema. Thoracic Surgery

Hemothorax Hemothorax A hemothorax is a collection of blood in the pleural cavity. Hemothorax most commonly occurs due to damage to the intercostal arteries or from a lung laceration following chest trauma. Hemothorax can also occur as a complication of disease, or hemothorax may be spontaneous or iatrogenic. Hemothorax:

• Blood in chest cavity leading to lung compression Compression Blunt Chest Trauma
• Signs and symptoms:
  • ↓ breath sounds
  • Dullness on percussion Percussion Act of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained. Pulmonary Examination
  • Tracheal deviation Tracheal Deviation Pneumothorax, mediastinal shift
  • ↓ tactile vocal fremitus
  • ↓ jugular venous pressure Jugular Venous Pressure Portal Hypertension
• Management:
  • Chest tube
  • Thoracotomy Thoracotomy Surgical incision into the chest wall. Thoracic Surgery (if > 1.5 L blood drained directly or continuous high output)

Pulmonary contusion:

• Bruised lung
• Signs and symptoms:
  • Onset < 24 hours after blunt thoracic trauma
  • Tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children, hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome
  • Imaging shows patchy alveolar infiltrates not restricted by anatomical borders (non-lobar opacification).
• Management:
  • Oxygen
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control, chest physiotherapy Physiotherapy Spinal Stenosis, mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing in severe cases

Acute respiratory distress syndrome Acute Respiratory Distress Syndrome Acute respiratory distress syndrome is characterized by the sudden onset of hypoxemia and bilateral pulmonary edema without cardiac failure. Sepsis is the most common cause of ARDS. The underlying mechanism and histologic correlate is diffuse alveolar damage (DAD). Acute Respiratory Distress Syndrome (ARDS) (ARDS):

• Diffuse inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of lung parenchyma due to different etiologies
  • Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock
  • Acute pancreatitis Pancreatitis Inflammation of the pancreas. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of chronic pancreatitis. The two most common forms of acute pancreatitis are alcoholic pancreatitis and gallstone pancreatitis. Acute Pancreatitis
  • Massive transfusion
  • Trauma
• Signs and symptoms:
  • New worsening respiratory condition, usually after 24 hours of insult 
  • Imaging shows bilateral, patchy alveolar infiltrates ( pulmonary edema Pulmonary edema Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary Edema).
  • Hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome with PaO₂/FiO₂ ratio < 300 mm Hg
• Management: mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing

Pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia:

• Infection of lung parenchyma often due to hypoventilation, usually polymicrobial
• Signs and symptoms:
  • Hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage
  • Tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
• Management: broad-spectrum Broad-Spectrum Fluoroquinolones antibiotics

Blunt cardiac contusion:

• Injury to cardiac muscle Cardiac muscle The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Muscle Tissue: Histology due to trauma often associated with sternal fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
• Signs and symptoms:
  • New electrocardiogram Electrocardiogram An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) ( ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)) findings (arrhythmias)
  • ↑ cardiac enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes (troponin) 
• Management: Treat complications (arrhythmias).

Differential Diagnosis

• Pulmonary contusion: parenchymal lung injury and accumulation of blood within the lung tissue after chest trauma. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children, and hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome. Imaging shows patchy alveolar infiltrates not restricted by anatomical borders. Management involves oxygen administration, pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control, chest physiotherapy Physiotherapy Spinal Stenosis, and mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing in severe cases.
• Pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax: abnormal collection of air in pleural space Pleural space The thin serous membrane enveloping the lungs (lung) and lining the thoracic cavity. Pleura consist of two layers, the inner visceral pleura lying next to the pulmonary parenchyma and the outer parietal pleura. Between the two layers is the pleural cavity which contains a thin film of liquid. Pleuritis due to laceration Laceration Torn, ragged, mangled wounds. Blunt Chest Trauma of lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy. Types of pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax include simple (spontaneous) and tension pneumothorax Tension Pneumothorax Pneumothorax. Exam findings include decreased breath sounds, hyperresonance on percussion Percussion Act of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained. Pulmonary Examination, and tracheal deviation Tracheal Deviation Pneumothorax away from tension pneumothorax Tension Pneumothorax Pneumothorax. Treatment includes needle decompression Needle Decompression Pneumothorax and chest tube placement Tube placement Surgical procedure involving the creation of an opening (stoma) into the chest cavity for drainage; used in the treatment of pleural effusion; pneumothorax; hemothorax; and empyema. Thoracic Surgery.
• Hemothorax Hemothorax A hemothorax is a collection of blood in the pleural cavity. Hemothorax most commonly occurs due to damage to the intercostal arteries or from a lung laceration following chest trauma. Hemothorax can also occur as a complication of disease, or hemothorax may be spontaneous or iatrogenic. Hemothorax: collection of blood in pleural cavity Pleural cavity Paired but separate cavity within the thoracic cavity. It consists of the space between the parietal and visceral pleura and normally contains a capillary layer of serous fluid that lubricates the pleural surfaces. Pleura: Anatomy. Usually occurs following lung laceration Laceration Torn, ragged, mangled wounds. Blunt Chest Trauma or damage to intercostal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with shortness of breath Shortness of breath Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea and chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. Exam findings include tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children, tracheal deviation Tracheal Deviation Pneumothorax, and dullness on percussion Percussion Act of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained. Pulmonary Examination. Management is with chest tube insertion and thoracotomy Thoracotomy Surgical incision into the chest wall. Thoracic Surgery if > 1.5 L of blood directly evacuated or collecting of > 1 L of blood over 4 hours.
• ARDS: severe inflammatory reaction of the lung that is characterized by pulmonary infiltrates due to alveolar fluid accumulation, not in cardiogenic etiology. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present in respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure. Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests shows diffuse bilateral lung infiltrates. Management depends mainly on treating underlying etiology and maintaining adequate oxygenation, which usually requires mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing.