Oxygen Delivery Systems and Pulmonary Tests

Nasal cannula is the most common delivery mode. Supports flowrates between 1 and 6 L/min

Facemask may or may not be supplemented with humidity. Supports flow rates 5-10 L/min. Delivers oxygen at 35-55% FiO2

Trach Mask / Collar: Humidified, delivers oxygen up to 40-70%

Venturi Mask: Variable adaptors enable selection of flow rates to influence FiO2. Adaptors provide more realistic approximation of FiO2. Side ports on mask allow for addition of room air

Non-Rebreather mask: Provides high concentration of oxygen (90-100%), one way valve separates mask from bag. Oxygen delivered to bag, exhalation does not enter bag

High flow nasal cannula: provides flow rate (25-60 L/Min) well above patients peak inspiratory rate. Delivers specific FiO2. Offers additional respiratory support through positive expiratory pressure (PEP) and elimination of CO2

Positive airway pressure: assists in splinting airways open.

Bilevel (BiPAP): settings can be adjusted separately for inhalation and exhalation

Continuous (CPAP): settings fixed for inhalation and exhalation

Mechanical Ventilation: provides support to those with impending or existing respiratory failure or those in need of airway protection. Delivered via nasal or oral endotracheal tube or via tracheostomy.

ETT for short term management and tracheostomy for long term support.

Pulmonary Diagnostic Tests and Procedures

Decubitus views are taken to confirm the presence of an air–fluid level in the lungs or a small pleural effusion. Depending on the location of the suspected disease, the patient is placed in the supine, prone, or right or left side-lying position.

The lordotic view is used to visualize the apical or middle (right middle lobe or left lingular segments) region of the lungs, or specifically to screen for pulmonary tuberculosis, which typically manifests itself in the apical regions.

Oblique views are taken to detect pleural thickening, to evaluate the carina, or to visualize the heart and great vessels.

The anteroposterior (AP) view is taken at the patient’s bedside when the patient is unable to travel to the radiology department

The optimal radiograph should be taken with the patient holding a deep inspiration. Furthermore, the entire chest should be visible on the radiograph

The various densities of the soft tissues (skin, subcutaneous fat, and muscle) normally blend together—called the summation effect.

Chest radiographs: Predominant diagnostic test to determine anatomic abnormalities and pathological processes within the chest

The radiograph of a patient with moderate to severe chronic obstructive pulmonary disease will show widened intercostal spaces, flattened hemidiaphragms, squared-off costophrenic angles, and rib angles that approach 90 degrees.

The Hila Formed by the root of the lungs (comprising the pulmonary blood vessels, the bronchi and a group of lymph nodes), the hila are at about the T4-T5 level and appear as poorly defined areas of variable density in the medial part of the central portion of the lung fields

Specific lung lesions are assessed by observing the lung fields for any abnormal density that obliterates the vascular markings or that alters the distribution of the densities within the lung fields

Vascular markings that are increased on a chest radiograph are indicative of early left ventricular failure.

Acute changes would include fluffy infiltrates or increased opacity. Chronic changes include flattened diaphragms, changes in rib angle and intercostal spaces, abnormal lung volumes, and interstitial thickening.

Computed tomography (CT), or digital chest radiography, involves a narrow beam of xrays moving across the field of examination in such a way as to define successive adjacent columns of tissue, a process called translation

Computed tomography scanning of the chest primarily has been used for diagnosis of tumors versus calcifications or nodules. High-resolution CT has become the optimal diagnostic method for recognizing parenchymal abnormalities.

Pulmonary Arteriography Emboli are read on arteriography as one of the following: ▪ Complete obstruction ▪ Intraluminal filling defects ▪ Decrease in flow rate

Magnetic resonance imaging (MRI) involves the interaction of stimulated hydrogen nuclei and a strong magnetic field. An MRI scanner produces a gradient magnetic field in the region of the body to be imaged. An MRI is primarily indicated for the evaluation of chest wall processes that may involve bone, muscle, fat, or pleura

Magnetic resonance imaging may be indicated in individuals with abnormal chest radiographs that show a nodule or mass. An MRI could show an enhanced picture of the mass before surgical resection or biopsy, or may be used to enhance the pleural area to distinguish between fibrosis and the presence of nodules

Ventilation and Perfusion Scans:

To measure the regional distribution of ventilation in the lungs, the patient breathes xenon gas ( 133Xe). The test is usually performed with the patient in a sitting or supine position

To measure the regional distribution of pulmonary blood flow in the lungs, the patient is injected intravenously with radioactive iodine (I-131) and serial perfusion scans are made over the lung fields as the blood perfuses the lungs

Hemoglobin: Males 14 to 17Gm/dL Females 12–16Gm/dL

Hematocrit (%) Males 41% to 50% Females 36% to 47%

Platelets 140 to 400,000/mm

Coagulation PT 11 to 13.5 sec PTT 30 to 45 sec

ARTERIAL BLOOD GASES: Crucial to assessment of problems related to Acid–base balance, Alveolar Ventilation, Oxygenation

Blood gas analysis: To determine the nature and severity of the illness with accuracy, the relationship of arterial pH and arterial CO2 tension is assessed

Acid–base balance: Assessment blood pH—nature and magnitude of respiratory and metabolic disorders, Lungs and kidneys regulate

Henderson–Hasselbalch equation: Carbonic acid to bicarbonate ion relationship Permits a quick identification of four primary disorders based on pH

and CO2

Normal human blood pH = 7.4 \n pH <7.4 is acidemia (Acidosis) \n pH <7.4 is alkalemia (Alkalosis) \n Base excess (BE)—reflects concentration of bicarbonate in body

Respiratory Acidosis: Causes: Hypoventilation, Over sedation, Head trauma, NM disorders, Cardiac arrest, Chest trauma, COPD, Pneumonia. Symptoms include tachycardia, confusion

Metabolic Alkalosis: Loss of acid from GI tract or kidney. tany, Hypertonic muscles, Numbness

Metabolic Acidosis: Increased production of acids (ketoacidosis) Fatigue, weakness, DOE

Respiratory Alkalosis: Hyperventilation, Anxiety/fear/pain, Excessive mechanical ventilation

PaO2 = 60 to 80 mm Hg—mildly hypoxemic \n PaO2 = 40 to 60 mm Hg—moderately hypoxemic \n PaO2 = 40 mm Hg—severely hypoxemic

Lung findings: Darker areas: radiolucent, Pneumothorax, Bullae, Air bronchograms. Lighter areas: Opacities, “infiltrates”, Blood, Pus, Water

Ventilation/Perfusion Ratio: 0.80, Usually ordered when a pulmonary embolus is suspected

unless a minimally invasive approach is not an option, posterolateral thoracotomy is most commonly used for pulmonary thoracic procedures. 2,3 Cardiac procedures are performed almost exclusively through a median sternotomy of varying length, although the great vessels and valves are sometimes approached via a thoracotomy incision

__Invasive Monitoring Arteria__l Line In the severely ill patient with hemodynamic compromise, a low stroke volume and excessive peripheral vasoconstriction may make Korotkoff sounds impossible to hear and arterial pulsations difficult to detect. Patients who are on vasoactive drips typically require continuous blood pressure management

The central line is a central venous catheter inserted most commonly through the subclavian or jugular vein; however, the femoral access may also be used if the need arises. The catheter is placed by a physician and is advanced to rest in the proximal superior vena cava.

The pulmonary artery catheter must be inserted by a physician. It is introduced via a central venous access point (e.g., internal jugular or subclavian vein), passing from the vena cava into the right atrium, through the right atrioventricular (tricuspid) valve into the right ventricle, through the pulmonary valve, and into the pulmonary artery

__Extracorporeal membrane oxygenation (ECMO)__is a \n life support machine. People who need ECMO have a severe and life-threatening illness that stops their heart or lungs from working properly. Replaces the function of the heart and lungs

Breathing Exercises

Inspiratory-focused breathing exercises: Incentive spirometer, diaphragmatic, stacked breaths (terminal exhalation), progressive volume breaths (intermittent exhalation), facilitated segmental breaths, may add inspiratory hold

Expiratory-Focused Breathing: Pursed lip breathing, expiratory prompts: bubbles, kazoos, pinwheels

Clearance Interventions

Sputum assessment: color, consistency, quantity, odor

Problematic forceful cough: secondary to muscular weakness, assisted coughs, positioning and compensatory strategies. Secondary to pain: Huff, splint, stacked coughs (terminal cough) progressive force coughs (intermittent coughs) Cough leads to bronchospasm (huff)

Secretion-Clearance interventions: postural drainage, percussion, vibration. Positive expiratory pressure, active cycle of breathing, autogenic drainage, high frequency chest wall oscillation suctioning

Positive expiratory Pressure: Created within the lungs via use of devices for exhalation resistance. Splits airway open to enable air flow behind accumulated secretions. Can be combined with instrumentation providing oscillation in addition to positive pressure.

Active cycle of breathing: Goal is secretion mobilization. cycle of alternating breathing control breaths with thoracic expansion breaths

Breathing control: gentle title volume breathing to minimize the work of breathing, similar to diaphragmatic breathing

Thoracic Expansion Breaths: 2-3 deep inspirations approaching IRV

High frequency chest wall oscillation: Pneumatic chest percussion and vibration. Patient wears an inflatable vest connected to a external power source. Needs to be done in conjunction with a cough

Tracheal suctioning: Traditional or in-line technique, enables airway secretion clearance within upper airway (Oral, Nasal, Tracheal)

Yankauer suctioning provides oral cavity secretion clearance and is least invasive

Restrictive lung dysfunction (RLD) is an abnormal reduction in pulmonary ventilation due to restriction of expansion by the chest wall or the lungs. Lung expansion is restricted, and therefore the volume of air or gas moving in and out of the lungs is decreased.

Three major aspects of pulmonary ventilation must be considered to understand the pathophysiology of RLD. They are (1) compliance of both the lung and the chest wall; (2) lung volumes and capacities; and (3) the work of breathing

In order to classify pulmonary disease into one of the two categories (obstructive vs. restrictive), pulmonary function testing (PFT) needs to be performed. With RLD, PFTs will typically show a decrease in almost all volumes and capacities with fairly normal flow rates, along with a decrease in diffusion capacity

Restrictive lung dysfunction eventually causes all the lung volumes and capacities to become decreased. Because the distensibility of the lung is decreased, the inspiratory reserve volume (IRV) is diminished.

Restrictive disease: an inspiratory impairment may ultimately reduce all lung volumes, not just inspiratory volumes. Caused by decreased compliance of lung or chest wall and reduced inspiratory effort. SS: tachypnea, dyspnea, decreased breath sounds and nonproductive cough

Left sided HF: pulmonary symptoms

Pulmonary symptoms: Right sided HF

Diagnostic assessments: CXR and PFTs

CXR: radiopacities, regions with retained secretions or fluid and atelectatic segments.

PFTs: Reduced lung volumes, reduced FVC

 \n <<Fibrotic Disease: Focal lung lesions representing progression of an inflammatory process to tissue fibrosis. Destruction of alveolar capillary beds, irregular shape and size alveolar spaces, decreased lung compliance. SS: diminished breath sounds with potential for crackles (DOE, to SOB)<<

Diagnostic findings of fibrotic disease: CXR: consistent with reticulonodular pattern (honeycombing), CR scan consistent with ground glass findings, PFTs consistent with restrictive pathology, ABGs consistent with decreased PaO2 with unchanged CO2

Sarcoidosis: Uniform, epithelioid, fibrotic granulomas within multiple organs. Most common locations in lung and lymph nodes. Pulmonary insufficiency results in death in 5-7% of patients. SS: diminished breath sounds with crackles in lower lobes, dyspnea of unknown onset, dry non-productive cough, malaise, fatigue

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) occur as the result of a disease that causes inflammation, leading to increased pulmonary vascular permeability, increased lung weight, and loss of aerated tissue. 51 It was previously named “adult” respiratory distress syndrome to distinguish it from neonatal acute respiratory failure, which was due to immature lungs with inadequate surfactant production. It was later changed to “acute” respiratory distress syndrome as it became known that diffuse lung injury from a variety of causes could affect both adult and pediatric populations. Also recently updated was the term

Pleural involvement may include pleuritis, pleural friction rub, repeated small exudative pleural effusions, and pleural thickening and fibrosis. These pulmonary abnormalities can result in pain and some RLD. Pneumonitis causes an inflammatory reaction in the lung, including patchy infiltrates, which can resolve spontaneously or can progress to fibrotic changes.

Pneumonia: inflammation of the parenchyma or alveoli following a lung infection. Increased mucous production, decreased gas exchange. Causes include community-acquired or hospital, inhalation of bacteria or virus

Tuberculosis: infection caused by myobactorium tuberculosis. Can present as a primary infection or as a reactivation of a prior infection.

Sequelae secondary to MSK neuromuscular conditions: which may impact the shape, strength, or flexibility of the chest wall and or muscles of respiration can impact the pulmonary system. Pulmonary signs and symptoms include diminished breath sounds, dyspnea on exertion and decreased chest wall expansion

Obstructive Disease

Obstructive disease is an expiratory impairment. Volumes increase, may progress to decreased inspiratory volumes. Causes are from increased resistance to airflow (lumen obstruction)

SS of obstructive disease: tachypnea, dyspnea, decreased and or adventitious breath sounds, chronic (potentially productive) cough, and characteristic MSK changes

CXR obstructive disease: Hyperinflation with flattened diaphragm. Radiopacities (appear white) reveal regions with retained secretions. Cough instruction. PFTs: increased lung expiratory volumes, decreased lung inspiratory volumes with worsening obstructive disease.

Asthma: hyperirritability of the tracheobrachial tree. Results in bronchospasm, inflammation of the bronchioles and excess mucous secretion causes increased resistance to airflow. SS: Wheezing or diminished / absent breath sounds.

Medical management of Asthma: Brochodilators, corticosteriods, beta adrenergic agonist

Aerobic training at moderate to high intensity for asthma: 20 minutes, 2 times/week, minimum of 4 weeks. Contraindicated during acute exacerbation.

Chronic Bronchitis: Chronic inflammation and swelling of bronchial mucosa. Leads to hypersecretion of brochial mucous given hyperplasia of mucous glands. Creates irreversible ling damage given scarring of mucous membranes results in dilation of alveoli. SS: Cyanosis and barrel chest deformity, SOB, DOE, tachypnea, chronic productive cough.

Hypoxic Drive: An obstructive disease consideration: consequence of retained CO2. Chronic hypercapnia blunts sensitivity of central chemoreceptors to detect changes in CO2. Body fails to naturally increase respiratory rate to eliminate CO2 excess.

Emphysema: destruction of elastic fibers surrounding the alveoli given deficiency of alpha 1-antritrypsin. Decreased number of alveoli, increased size of alveolar sac and ducts, theraby reducing elastic recoil. Overall reduced surface area for gas exchange. SS: Normal coloration, tachypnea, increased WOB with pronounced accessory muscle use. Obstructive disorder

COPD stands for Chronic Obstructive Pulmonary Disease. It is a chronic respiratory disease that causes airflow obstruction, making it difficult to breathe. This condition is typically progressive and can lead to significant morbidity and mortality if not managed effectively.

The primary cause of COPD is smoking, but exposure to environmental pollutants such as dust, chemical fumes, and air pollution can also contribute to the development of the disease. COPD is characterized by chronic bronchitis, emphysema, or a combination of both.

Symptoms of COPD include shortness of breath, wheezing, chest tightness, chronic cough, and production of sputum. Treatment for COPD includes quitting smoking, medications to manage symptoms, pulmonary rehabilitation, and oxygen therapy in severe cases.

Bronchiectasis is a chronic respiratory condition characterized by an abnormal widening and thickening of the bronchi, the airways that branch off from the trachea and lead to the lungs. This widening and thickening can cause mucus buildup, making it difficult to clear the airways and leading to recurrent infections.

The most common cause of bronchiectasis is a previous respiratory infection, such as pneumonia or tuberculosis. Other causes include cystic fibrosis, autoimmune diseases, and inhaling foreign objects or chemicals.

Symptoms of bronchiectasis include a persistent cough, frequent respiratory infections, shortness of breath, chest pain, and fatigue. Treatment for bronchiectasis involves managing symptoms and preventing complications such as lung infections. This may include antibiotics, chest physiotherapy, bronchodilators, and in severe cases, surgery to remove damaged lung tissue.

Cystic fibrosis (CF) is a genetic disorder that affects mainly the respiratory, digestive, and reproductive systems. It is caused by a mutation in a gene called the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which produces a protein that regulates the transport of salt and water across the cell membranes.

The defective CFTR protein leads to the accumulation of thick, sticky mucus in the lungs and other organs, which can lead to chronic infections, lung damage, and difficulty breathing. It can also affect the pancreas, preventing the release of digestive enzymes, leading to malnutrition and growth problems.

Symptoms of cystic fibrosis can vary, but typically include chronic cough, frequent respiratory infections, difficulty breathing, poor growth and weight gain, and digestive problems such as diarrhea and abdominal pain.

There is no cure for cystic fibrosis, but treatments such as airway clearance techniques, antibiotics, and bronchodilators can help manage symptoms and prevent complications. Other treatments may include pancreatic enzyme replacement therapy, nutritional support, and gene therapy.

Crackles are caused by the sudden opening of small airways and alveoli that were previously collapsed or filled with fluid, mucus, or other secretions. They are often heard in patients with conditions such as pneumonia, heart failure, or interstitial lung disease. Crackles can be further classified as fine or coarse, depending on the timing, pitch, and quality of the sound.

Stridor is a high-pitched, musical sound heard on inspiration or expiration that is caused by the narrowing of the upper airway. It is often associated with conditions such as croup, epiglottitis, or anaphylaxis.

A wheeze is a high-pitched, whistling sound heard on expiration that is caused by the narrowing of the lower airways. It is often associated with conditions such as asthma, chronic obstructive pulmonary disease (COPD), or bronchiolitis.

A pleural friction rub is a creaking or grating sound heard on inspiration or expiration that is caused by the inflammation of the pleural surfaces. It is often associated with conditions such as pleurisy or pneumonia.