Respiratory assessment and SOB Flashcards
What does PO2 measure?
The amount of dissolved oxygen in the blood
What is the definition of hypoxia?
Lack of oxygen at the tissue level
What is hypoventilation?
Slow resp rate and/or low tidal volume
How much oxygen in a full B size cylinder?
200L
How much oxygen in a full C size cylinder?
400-490L
How much oxygen in a full D size cylinder?
1500L
Hudsen face masks with a reservoir bag are used for which patients?
Patients with spontaneous breathing who are acutely hypoxic and require high concentrations of oxygen
Normal PO2 in the blood should be between ____ and ____.
80 and 100mmHg
What are some things that can cause false PO2 readings?
- Carbon monoxide poisoning
- Hypothermia
- Excessive ambient light
- Vasoconstriction
- Pt movement
- Nail polish
- Hypotension
- Jaundice
What SPO2 range is a suitable goal with a stable COPD patient?
88 to 92%
What SPO2 range is a suitable goal with a stable patient?
94 to 98%
What is asthma?
A chronic inflammatory disorder of the airway characterised by recurring episodes of wheezing/breathlessness/chest tightness/coughing/mucous production
What are the risk factors for asthma?
- Family hx
- Smoking
- Allergen exposure
- Recurrent respiratory infections
- Living in urban areas
- Air pollution
- Hygiene hypothesis (controversial)
What is the pathophysiology of asthma?
Hyper-responsiveness of the airway to inflammatory mediators
What are the two types of asthma triggers?
Allergens and irritants
Inflammatory mediator release causes what in asthma?
- Bronchial smooth muscle spasm
- Oedema
- Thick mucous production
- Thickening of the airway wall
- Further hyper-responsiveness of the airway
- Neuropeptide release
Mediators and immune cells lead to…
Cell damage and further airway obstruction
What are the two main syndromes of COPD/COAD?
Emphysema and chronic obstructive bronchitis
What are the differences between asthma and COPD?
- COPD is not fully reversible
- COPD is progressive
What are the risk factors for COPD?
- Active or passive smoking
- Occupational exposure
- Air pollution
- Genetics
What is the definition of chronic obstructive bronchitis?
Hyper-excretion of mucous and chronic productive cough for at least three months of the year for two consecutive years
Describe some pathophysiology points of chronic obstructive bronchitis
- Irritants cause airway inflammation
- Thick mucous is secreted
- Bronchial infiltration by neutrophils, macrophages, and lymphocytes
- Airway defence mechanisms are compromised, increasing the likelihood of pulmonary infections leading to bronchospasm and productive cough
- Continuous inflammation causes oedema
- Starts with bronchi and progresses to bronchioles
- Mucous glands and goblet cells increase in size and number, progressively narrowing the airway causing expiratory obstruction
What is the definition of emphysema?
Abnormal permanent enlargement of gas exchange airways accompanied by destruction of the alveoli walls and associated capillary network
Describe the pathophysiology of emphysema
- Inhaled oxidants induces inflammation
- Inflammation over time causes alveolar destruction and loss of compliance
- Loss of surface area and capillaries causes V/Q mismatch
- Expiration becomes difficult as alveoli stiffen
- Air trapping results in a barrel chest
- Significant energy put into breathing
What are the most common causes of acute respiratory distress syndrome (ARDS)?
Sepsis and multi-system trauma
What is ARDS?
A life-threatening condition involving lung inflammation and alveolar capillary damage
What are some other causes of ARDS?
- Pneumonia
- Burns
- Aspiration
- Pancreatitis
- Blood transfusions
- Drug overdose
- DIC
Describe the pathophysiology of ARDS
- Inflammation damages alveoli and capillaries
- Severe pulmonary oedema and hypoxaemia follow
- Fluids, proteins, and WBCs leak into the interstitial space
- Interpleural shunting occurs
- Epithelial cell damage due to inflammation causes platelet aggregation and thrombus formation
True or false: damage in ARDS can be direct or indirect
True
In what time frame will the clinical manifestation of ARDS be seen after the initial insult?
Within 24 hours
What are the signs/symptoms of ARDS?
- Severe dyspnoea
- Rapid shallow breathing
- Inspiratory crackles
- Reduced compliance
- Hypoxaemia unresponsive to O2 therapy
What is pneumonia?
Infection of the lower respiratory tract caused by bacteria, viruses, fungi, protozoa, or parasites
What are the risk factors for pneumonia?
- Old age
- Immunosuppression
- Underlying disease
- Alcoholism
- Smoking
- Malnutrition
- Immobilisation
What are some common causes of pneumonia?
- Bacteria (streptococcus pneumoniae)
- Influenza
- Legionella’s disease
Should you always expect to hear crackles on auscultation of pneumonia patients?
No
Describe the pathophysiology of pneumonia
- Aspiration of oropharyngeal secretions
- Inhalation of microorganisms
- Bacteria infiltration of lungs via blood
- Large concentrations of bacteria/viruses overwhelm the alveolar macrophages
- Immune mediator release causing damage to bronchial mucous membranes and alveoli and associated capillaries
- Bronchioles fill up with infectious debris and exudate causing V/Q inequality
What are the clinical manifestations of pneumonia?
- Usually preceded by an URTI
- Fever
- Chills
- Productive cough
- Malaise
- Pleural pain
- Dyspnoea
- Haemoptysis
- Inspiratory crackles
Describe the pathophysiology of tuberculosis
- Mycobacterium tuberculosis (transmitted through airborne droplets)
- Microorganisms lodge in upper lung lobes
- Bacteria multiplies causing inflammation
- Bacteria infiltrate lymphocytes
- Macrophages and neutrophils seal off bacterial colonies, forming tubercules
- Infected tissue in tubercules dies
- Scar tissue forms around tubercules
- Tubercules remain dormant until immune system weakens or bacteria escapes
Describe the clinical manifestations of tuberculosis
- Fatigue
- Weight loss
- Lethargy
- Loss of appetite
- Chest pain
- Low grade fever
- Purulent cough
- Night sweats
- Dyspnoea
- Haemoptysis
What is acute bronchitis?
Infection of the bronchi
- Self limiting
- Usually viral
- Purulent sputum may occur
Does influenza trigger an immune response?
Yes (mediators -> airway oedema -> excess mucous production)
What is a pneumothorax?
Presence of free air in the interpleural space
What are the different types of pneumothorax?
- Traumatic
- Spontaneous
- Iatrogenic
- Secondary
What causes iatrogenic pneumothorax?
Clinical procedures (central lines or decompression of a non-tension pneumothorax)
What are the clinical features of pneumothorax?
- Occurs suddenly
- May be associated with sneezing, coughing, hyperventilation, or breathing deeply
- 90% cases have chest pain on the affected side which may be dull, sharp, and may radiate to back/neck
- 80% cases complain of dyspnoea
- Reduced breath sounds on affected side
- Reduced chest movement of affected side
- Subcutaneous emphysema may occur
What are the signs of a tension pneumothorax?
Signs of a pneumothorax, plus:
- Decreased respiratory function
- Decreased cardiovascular function
- Increased JVP
- Tachycardia
- Tracheal deviation (late sign, always away from site of injury)
What is the leading cause of lung cancer?
Smoking (90%)
What are the risk factors for lung cancer?
- Amount smoked per day
- Years of smoking
- Advanced age
- COPD
Describe the pathophysiology of lung cancer
Carcinogens in tobacco cause genetic mutations in cells, leading to carcinomas. Progression of carcinomas leads to invasion of surrounding tissue. Metastasis develop and travel thoughout the body.
