Respiratory I

Upper airway anatomy

Nasal cavity, sinuses, pharynx

Lower airway anatomy (in order)

Trachea, carina, mainstem bronchus, segmental bronchus, bronchiole, alveolar duct, alveoli

Pulmonary circulation

-Deoxygenated: SVC/IVC→RA→RV→Pulmonary Artery→Pulmonary capillaries

-Oxygenated: Pulmonary veins→LA→LV→aorta & body

-Continuous circuit (just split into deoxygenated and oxygenated)

Bronchial circulation

Tracheobronchial tree an lungs supply blood via bronchial arteries via thoracic aorta

-Blood returns to the heart via the pulmonary vein, bronchial veins, and bronchopulmonary veins

Lungs

Site of external respiration, exchange of gases occurs at the alveolar level

Type 1 alveoli

Constitutes the air/blood barrier (about 95% of cells)

-Gas exchange

Type 2 alveoli

Produces surfactant to prevent lung collapse

Vital capacity (VC

Maximum volume which can be ventilated in a single breath

Residual capacity

The amount of gas left in the respiratory system at the end of a normal breath

Total lung capacity (TLC)

Total volume of gas contained in the respiratory system (VC + RC)

Tidal volume (vt)

The amount of air inhaled and exhaled during normal breathing

Functional residual capacity (FRC)

Amount of gas left in the respiratory system at the end of exhalation

Minute volume (minute ventilation) (Mv)

The total tidal volume over 1 minute

Anatomical dead space

Gas present in the upper airway, trachea, major bronchi, and bronchioles

-NOT INVOLVED IN GAS EXCHANGE/JUST PASSAGEWAYS

Functional dead space

Structures that should be involved in alveolar ventilation, but are unable to participate due to disease processes

Physiologic dead space

Total dead space in lungs and alveoli due to pathology

-Includes both the anatomical space and functional dead space

Breathing: external respiration

Inhalation of gases (most importantly oxygen) and exhalation of gases (most importantly CO2)

-Both U/L airways

-Contraction and relaxation of muscles (diaphragm, intercostal) causing negative pressure in the thoracic cavity

-Travels from the nares or mouth to alveoli. Approx 23 branches of bronchioles

-O2-CO2 exchange at the alveolar level Type

-Exhalation is passive

Cellular respiration (internal respiration)

Biochemical processes that occurs in all living beings;inside mitochondria

-Glucose is oxidized in the presence of xylem to form CO2 and water r

-Can be aerobic or anaerobic (think lactic acid)

-Involuntary ; no muscular movement

Crackles

Adventitious breath sounds

-Air flowing by liquid = crackles upon inhalation

-Fine, medium, or coarse classification

Wheezes

Air flowing through constricted airways

-Musical pitches heard on in/expiration, usually bilateral

-Unilateral are usually obstruction by a foreign object

Rhonchi

Air flow over thick secretions

-Usually disappears after coughing

-Continuous and prolonged

Friction rubs

Inflammation of the pleural space causes friction rubs

-Dry, rubbing, crackling sounds usually caused by inflammation or loss of pleural fluid

-Inspiration/expiration

Common respiratory problems

-Resonance: low-pitched hollow sounds

-Tactile fremitus: Assessment of vibrations in a patient’s chest/indirect measurement of air and density of tissue

Differences between breathing and respiration

Breathing is the physical process of inhaling and exhaling air, while respiration refers to the biochemical process of gas exchange in cells, specifically the uptake of oxygen and release of carbon dioxide

Hypoxia

A decrease in tissue oxygenation. Inadequate oxygen supply to meet the demands of the cells

-Can be due to external (breathing) or internal respiration (perfusion)

-Measured by ABG, O2 saturation, or picked up via physical interview & assessment

Hypoxemia hypoxia

Decreased diffusion into the blood

-Hypoventilation, high altitudes, ventilation-perfusion mismatch, alveolar shunting (atelectasis)

Circulatory hypoxia

Inadequate capillary circulation

-Decreased cardiac output, shock, cardiac arrest

Anemia hypoxia

Decreased hemoglobin concentrations

Histotoxic hypoxia

Toxins such as carbon monoxide which interfere with the ability of hemoglobin to carry oxygen or ability of tissues to use it

Atelectasis

Collapse of portion of lung resulting in reduced or absent gas exchange

-Secondary to the alveoli becoming “airless” without the ability to replace the air from breathing (could become filled with alveolar fluid)

-Most common: post-op, immobilized pt’s, pt’s with rapid, shallow breathing

S/sx of atelectasis

Silent until large enough to cause hypoxia: fever, cough, shallow breathing, wheezing, Rhonchi

-Other causes: obesity, obstructive sleep apnea, COPD, obstructions

-Can get better with treatment. If worsens, can cause pneumonia, pulmonary edema, or respiratory failure

Carbon monoxide poisoning

A condition resulting from the inhalation of carbon monoxide, which can cause symptoms like headaches, confusion, and even death if severe

1.CO2 enters via respiration

2.CO2 combines with hemoglobin to form carboxyhemaglobin

3.Carboxyhemaglobin hinders the delivery of oxygen to body cells, thus leading hypoxia

Carbon monoxide poisoning treatment / levels

Anything greater than 10% of CO in the blood is an issue

-Removal from source of CO

-O2 sat unreliable in txt/ need to check an ABG

-100% oxygen via non rebreather mask

-Repeat levels and ABG to gauge improvement

O2 delivery %’s

-Room air: 21%

-Nasal cannula: 1 (24%)-6(50%) liters per minute

-Venturi (venti) mask: 28-50%

-Non-rebreather mask: 100%

-Trach mask: 21-100%

Chest tubes

A medical device used to remove air, fluid, or pus from the pleural space, providing assistance in re-expanding the lung and improving breathing

Pneumothorax

A condition where air leaks into the pleural space, causing the lung to collapse

-Treatment may involve chest tubes or needle decompression to remove excess air

Hemothorax

A condition where blood accumulates in the pleural space, often resulting from trauma or injury

-Treatment typically involves chest tubes to drain the blood and restore normal lung function

Flutter valve

Handheld device used to help clear mucus from the lungs

-Oscillatory therapy to loosen secretions in the lungs Via vibrations/positive expiratory pressure device

-Tight seal around mouthpiece;blow into device with a forceful exhalation, + vibratory expiratory pressure

-2-3 huff coughs every hour

Incentive Spirometer

Facilitates sustained slow deep breaths

-10 x hourly, ideally held at TLC for 4-5 seconds each breath

Metaneb

Combines lung expansion, secretion clearance, and aerosol delivery

-High frequency oscillation therapy through continuous positive expiratory pressure / can integrate aerosol medication delivery

Peak flow meter

Portable device used to measure peak expiratory flow

-Used in individuals with asthma to measure lung function BEFORE symptoms occur

Inferior Vena Cava Filter

Temporary reduction in incidence of PE from a DVT

-Only placed in pt’s with contraindication for anticoagulation

-IVC filter fracture, filter migration, and embolization are risks of long-term use

Ekosonic Endovascular System (EKOS)

Ultrasound pressure and acoustic streaming along with thrombolytic agents to dissolve clots

-Considerations: alteplase/heparin running, bleeding, occlusions, dysrhythmias, vials, vascular checks, strict I / O’s, bedrest, bleeding precautions

Continuous positive airway pressure ventilation (CPAP)

Noninvasive mode of ventilation used for home or hospital setting to increase FRC

-Prevents alveolar collapse, reduce work of breathing without the need for endotracheal intubation

-Indicators: Rising PCO2, hypoxia, obstructive sleep apnea or obesity hypoventilation disorder

-Will increase O2 while decreasing work of breathing, will increase intrathoracic pressure

Bevel Positive Airway Pressure Ventilation (BIPAP)

A noninvasive mode of ventilation that alternates between inspiratory and expiratory pressures

-Patients with respiratory failure, encouraging oxygenation and reducing the work of breathing. Main difference is 2 pressures instead of one

-As pressure support is increased lungs will expand more

Contraindications / risks of noninvasive ventilation

-Contraindications: apnea, shock, inability to maintain an airway, pneumothorax, rapid deterioration, N / V, agitation

-Risks: N / V, pneumo, hypo, pressure ulcer, stomach bloating, dry mouth, trouble clearing secretions

Intubation

The process of placing a tube into the trachea to secure an airway, often used in emergency situations or during surgery

-It allows for mechanical ventilation and administration of anesthetics

Why do we intubate?

Hypoxia, hyper apnea, airway protection, airway injury, impending airway compromise, high risk of aspiration

Risk of intubation

Injury to throat, trachea, teeth/dental work, endotracheal tube malposition, right main stem intubation

-Gastric: aspiration

-Pneumomediastinum or pneumothorax, hypoxemia, post-intubation hypotension

Mechanical ventilation

Deliver high concentrations of oxygen to the lungs

-Removes excess CO2, decreases energy expended during acute phase illness, airway protection (neuromuscular disease, inability to maintain airway)

Ventilator Alarms: DOPE

D (Displacement): ET tube moved or dislodged. Sudden hypoxia, air leak, no chest rise. ACTION: Check tube placement

O (Obstruction): Tube blocked. Mucus plug kinked tubing, secretions. ACTION: Suction

P (Pneumothorax): Sudden hypoxia, unilateral breath sounds, hypotension.ACTION: Call rapid/decompress

E (Equipment): Ventilator or tubing issue. Circuit disconnects, sensor malfunction. ACTION: CHECK VENTILATOR CIRCUIT

All actions occur in the sequence listed above

Risk when mechanically ventilated

Aspiration, nosocomial infections, pneumothorax, lung damage, inability to discontinue support, pressure ulcers, malnutrition, side effects to medications

Needles circothyrotomy

Used in emergency for a failed airway

-Temporizing measure until definitive airway can be established

-Obstruction above the level of circothyroid membrane

Tracheostomy

A surgical procedure to create an opening in the trachea for long-term ventilation and airway management

-Acute respiratory failure with expected need for prolonged mechanical ventilation

-It is indicated for patients requiring prolonged respiratory support or who have obstructed airways

-Upper airway obstruction, difficult airway, copious secretions/inability to manage secretions, prophylaxis for extensive head/neck procedures, severe sleep apnea

Cuffed vs uncuffed tracheostomy

A cuffed tracheostomy has an inflatable balloon that seals the airway to prevent aspiration and allow controlled ventilation, while an uncuffed tracheostomy lacks this feature and is typically used for patients who can protect their airway