Respiratory Flashcards
What is dead space? And what is its V/Q?
Ventilation without perfusion. Infinity
What is shunt? What is its V/Q?
Perfusion without ventilation.
Zero.
What is V/Q mismatch?
Areas of the lung has different V/Q ratios due to different levels of perfusion and ventilation
Which lobes of the lungs has higher perfusion? How does this affect V/Q?
Lower lobes, therefore they have a lower V/Q
Do areas of high V/Q have high or low levels of oxygenation?
High, as the ventilation is able to saturate the blood
Do areas of low V/Q have high or low levels of oxygenation?
Low, because ventilation is unable to saturate the blood
What does V/Q mismatch cause?
Hypoxemia
How does V/Q mismatch cause hypoxemia?
Areas with increased perfusion, and therefore a low V/Q, will have low oxygen saturation as not enough oxygen through ventilation is present to saturate the blood.
Areas with decreased perfusion, and therefore a high V/Q, will have high oxygen saturation as there is enough oxygen present to saturate the lungs.
As there are more blood cells present with low oxygen, the blood overall will have low oxygen saturation
Causes of V/Q mismatch?
Pneumonia
COPD
Fibrosis
Asthma
Pulmonary embolism
Pulmonary hypertension
When does the oxygen-haemoglobin dissociation curve shift to the right?
In areas requiring more oxygen as haemoglobin more readily releases oxygen when the curve is shifted to the right
High pH, high temp, high PaCO2, high DPG
When does the oxygen-haemoglobin dissociation curve shift to the left?
At areas not requiring oxygen, as haemoglobin more readily holds onto oxygen when the curve is shifted to the left
High pH, low temp, low PaCO2, Low DPG
What is asthma?
A chronic inflammatory disorder of the airways causing inflammation, bronchial hyperresponsiveness and airway narrowing (bronchoconstriction)
What is asthma characterised by?
Inflammation, bronchoconstriction and mucous production
What are the clinical indicators of asthma?
Respiratory compromise
- Decreased ability to speak
- Increased work of breathing
- Tracheal tug
- Cyanosis
- Diaphoresis
- Altered level of consciousness
- Silent chest
- Hypotension
- Bradycardia
What is the pathophysiology of asthma?
- Exposure to trigger (e.g. cigarette smoke or cold air)
- Release of inflammatory mediators (e.g. histamines, interleukins, prostaglandins)
- Bronchial smooth muscle spasm and contraction mediated by acetylcholine, airway oedema, production of thick mucous, airway hyperresponsiveness, thickening of airway walls leading to airway remodelling
- Results in obstruction of the airways, limitation of airflow, air trapping respiratory acidosis, hypoxemia
What are some asthma complications?
- Respiratory failure (hypoxemia or hypercapnia) due to airflow limitation
- Status asthmaticus - acute severe and prolonged asthma attack lasting for 24 hours or more without improvement
How do you manage acute asthma?
- Correct significant hypoxemia with oxygen therapy
- Reverse airflow obstructions through reliever and preventer medications
- Plan to prevent further events through patient education
What should the patient be educated on when aiming to prevent future asthma events?
- The nature of asthma
- Definition of inflammation and bronchoconstriction
- Purpose and action of each medication
- Identification of triggers and how to avoid them
- Proper inhalation techniques
- How to perform peak flow monitoring
- How to implement an action plan
- When and how to seek assistance
What is pneumonia?
An acute infection of the lower respiratory tract caused by bacteria, viruses, fungi, protozoa or parasites
What are 4 different types of pneumonia?
- Community-acquired pneumonia
- Medical care-associated
- Aspiration pneumonia
- Opportunistic pneumonia
What is the pathophysiology of pneumonia?
- Inflammatory response - attraction of neutrophils, release of inflammatory mediators, accumulation of fibrinous exudates, red blood cells and bacteria
- Alveoli fill with fluid and debris (consolidation), and increased production of mucous (airway obstruction)
- These lead to decreased gas exchange
- Resolution of infection - macrophages in alveoli ingest and remove debris, normal lung tissue is restored, gas exchange returns to normal
What is COPD? What are the two diseases that come under COPD?
Progressive chronic disease characterised by irreversible obstruction of the airways.
1. Chronic bronchitis
2. Emphysema
What are some signs and symptoms of COPD?
- Shortness of breath
- Wheezing
- Chest tightness
- Ongoing chronic cough
- Difficulty with routine activities
- Fatigue
- Weight loss
- Muscle loss
What are COPD risk factors?
- Older age
- More common in men, however more women die from it each year
- Smoking
- Alpha 1 antitrypsin deficiency
- Long term exposure to irritants: second hand smoke, air pollution, dust or workplace fumes, biomass exposure
What is the pathophysiology of chronic bronchitis?
- Long term exposure to a trigger (smoke, pollution)
- This causes inflammation of the airway epithelium, leading to infiltration of inflammatory cells and release of cytokines which leads to continuous bronchial irritation and inflammation
- Chronic bronchitis (bronchial oedema, hyper secretion of mucous, bacterial colonisation of airways)
- Ciliary function is reduced, bronchial walls thicken, bronchial airways narrow and mucous may plug airways
- Leads to airway obstruction, air trapping, loss of surface area for gas exchange, frequent exacerbations
What is the pathophysiology of emphysema?
- Long term exposure to triggers (smoke, pollution)
- Inflammation of the airway epithelium
- Infiltration of inflammatory cells and release of cytokines
- Leads to a breakdown of lung elastic tissue
- This results in emphysema - destruction of alveolar septa and loss of elastic recoil of bronchial walls
- Results in a decrease in alveolar surface area which causes an increase in dead space and impaired oxygen diffusion
- Also results in hypoxemia, loss of elastic recoil and gas trapping
What is the evidence based management for COPD?
GOLD - Global initiative for chronic obstructive lung disease
COPD-X - confirm diagnosis, optimise function, prevent deterioration, develop a management plan and manage exacerbations
What are nursing management strategies for COPD?
- Education (smoking cessation)
- Medications
- Oxygen
- Respiratory assessment
- Psychosocial management
What is the target SpO2 for COPD patients? Why?
88-92%
Excessive oxygenation can lead to hypercapnia respiratory failure due to V/Q mismatch.
Areas of the lung that are poorly ventilated will have localised vasoconstriction to protect against V/Q mismatch. When oxygen is delivered, vasoconstriction will cease so ventilation will remain poor however perfusion will increase leading to decreased oxygenation and increased dead space
Worsens hypoxia and hypocapnia
What lines the lungs?
Visceral pleura
What lines the thoracic cavity (chest wall)?
Parietal pleura
What is pleural space?
Potential space between the two layers of pleura, with negative pressure
What are the 2 functions of pleural space?
- Helps regulate pressure inside and outside the lungs while breathing
- Fluid provides lubrication for pleural layers as they slide against each other
What is a pneumothorax?
A collection of air in the within the pleural space (usually at the apex)
What is the pathophysiology of a pneumothorax?
Air enters the pleural space, the negative pressure equalises, resulting in the lung collapsing
What are the two classifications of a pneumothorax?
- Closed (spontaneous) - air from inside the lung enters the pleural space due to the disruption of the visceral pleura without any apparent trauma
- Open - air from the outside enters the pleural space due to disruption of the chest wall and parietal pleura
What are the clinical manifestations of a pneumothorax?
- Chest pain - sudden onset, sharp, on affected side
- Dyspnoea
- Tachypnoea
- Anxiety, stress, agitation
- Tachycardia
- Decreased air entry at the apex
- Decreased chest movement
How do you diagnose a pneumothorax?
X-Ray
How do you treat a pneumothorax?
- Conservative management with repeat chest X-Rays
- ICC and UWSD
What are nursing considerations for a pneumothorax?
- Full set of vital signs
- Respiratory assessment
- End of bed test - full sentences
- Pain assessment
What is a pleural effusion?
Abnormal collection of fluid in the pleural space, usually at the base
What is the pathophysiology of a pleural effusion?
Secondary to another disease process
Why do pleural effusions take longer to be recognised?
They compensate slower, so symptoms appear later
What are the clinical manifestations of a pleural effusion?
- Pain (usually worse in inhalation)
- Dyspnoea
- Tachypnoea
- Anxiety, stress, agitation
- Tachycardia
- Decreased air entry at the base of affected side
How are pleural effusions diagnosed?
Chest X-Ray and CT scan, ultrasounds can also be used close to the base
How are pleural effusions treated?
- Treat the underlying cause
- Chest drainage: Thoracentesis or ICC
What are nursing considerations for pleural effusions?
- Full set of vital signs
- End of bed test - full sentences
- Pain assessment
- Respiratory assessment
What is a haemothorax?
Collection of blood in the pleural space
What is a haemopneumothorax?
Combination of air and blood in the pleural space
What is empyema?
Pus in the pleural space
What does an intercostal catheter do?
Drain blood/fluid/air from the pleural space and re-establish a negative air pressure in the pleural space
Where should the ICC be placed for a pneumothorax?
Apex of the lung to drain air
Where should a ICC be placed for a pleural effusion?
Base of the lung to drain fluid
What is a complication of an ICC and UWSD?
Can become dislodged or completely removed, therefore will no longer function resulting in a tension pneumothorax
What is a tension pneumothorax?
Progressed pneumothorax. Occurs when pressure in the pleural space pushes against the already collapsed lung which causes significant compression atelectasis
What is a tracheostomy?
A surgical procedure in which an opening is made into the trachea and an indwelling tube is placed
What are the functions of a tracheostomy?
- Overcome airway obstruction
- Facilitate mechanical ventilation support
- Enable the removal of trachea-bronchial secretions
What are the 2 types of tracheostomies?
- Temporary tracheostomy - elective procedure with a view to remove
- Permanent tracheostomy - a permanent airway is required
