Respiratory Flashcards
Upper respiratory system is composed of?
- nose - sinuses - pharynx - larynx - trachea
Components of the conducting zone
- nasopharynx - oropharynx - larynx - trachea - left and right bronchus - secondary bronchi - tertiary bronchi - bronchioles - terminal bronchioles - respiratory bronchioles
Most common upper respiratory disorders
- viral Upper Respiratory Tract Infections (common cold) - influenza (the flu) - can lead to pneumonia, sinusitis and middle ear infections - Rhinitis, inflammation of the nasal cavities - sinusitis - pharyngitis (viral) - tonsilitis (bacterial) - strep infection can lead to glomerulonephritis (kidney) or rheumatic fever (heart) - epiglottitis (usually viral, uncommon but an emergency as blocks the airway) - laryngitis (usually viral, swollen vocal cords) - pertussis (whopping cough) - epistaxis (nose bleeds - trauma, cocaine abuse, underlying health disorder)
Symptoms forming from inflammatory response
- swollen mucous membranes - nasal congestion and secretions - headache, fever, general malaise
Components of the respiratory zone
- alveoli - alveolar ducts
What main viruses cause URTIs?
- rhinovirus - adenovirus - coronavirus - parainfluenza virus - respiratory syncytial virus (RSV)
Manifestations of the flu
Respiratory ■Coryza (runny nose) ■ Cough, initially dry becoming productive ■ substernal burning ■ sore throat Systemic ■ fever and chills ■ malaise ■ muscle aches fatigue
Manifestations of tonsilitis and pharyngitis
Local ■ sore throat ■ Possible dysphagia and ear pain ■ Tender, swollen anterior cervical lymph nodes ■ Hoarse voice ■ Red, swollen pharyngeal mucous membranes and/or tonsils ■ Possible visible exudate on pharyngeal membranes and/or tonsils General ■ fever ■ general malaise ■ Arthralgia, myalgia
Drugs to treat colds
- as usually viral, antibiotics are ineffective.
- Codeine and pholcodine to treat non-productive coughs
- anticholinergics reduce nasal discharge
- expectorants bring up mucus and other material from the lower respiratory tract
- mucolytics thin mucus
- antihistamines reduce sneezing and runny nose
- antipyretic analgesics (commonly, paracetamol)
- sympathomimetic decongestants open the nasal passages by shrinking blood vessels in the mucus membrane of the nose
- demulcent (soothing) liquids, flavouring and sweetening agents, and alcohol
Structures of the lower respiratory system
- bronchi - lungs - alvioli - ribs - pleura - inter-costal muscles
Structures of the respiratory zone (where gas exchange takes place - aka parenchyma)
- respiratory bronchiles - alveolar ducts - alvioli
What is the carina?
the area between the bronchi at the end of the trachea, with sensitive nerves that cause bronchospasm or coughing
What are the two layers of the pleura?
- visceral - envelops the lungs - parietal - lines the thoracic cavity - pleural cavity between the two; negative pressure to maintain lung inflation and filled with fluid to lubricate
Respiratory volume and capacity are affected by?
- age - gender - weight - health status (disease, injury)
What happens during inspiration?
diaphragm contracts and flattens rib cage elevates, intra pulmonary pressure decreases and air rushes in.
What happens during expiration?
Expiration - diaphragm relaxes, ribs descend and intrapulmonary pressure rises and air flows out.
What are the major inter-costal muscles involved in breathing?
- scalenus muscles - serratus - transversus thoracis - sternocleidomastoid - pectoralis minor - rectus abdominus
What is tidal volume(TV)?
- the volume on regular inspiration ~500mL
what is inspiratory reserve volume (IRV)?
The amount of extra air you can take in after tidal inspiration ~3000mL
What is expiratory reserve volume(ERV)?
- the amount on top of tidal volume that you can breathe out in forced expiration ~1200mL
what is inspiratory capacity?
TV+IRV ~3500mL
what is vital capacity?
TV+IRV+ERV ~4000 - 5000mL
What is residual volume (RV)
the amount of air remaining in the lungs after full exhalation ~ 1200mL
What is functional residual capacity?
ERV+RV ~1800 - 2400mL
What is total lung capacity?
TV+IRV+ERV+RV ~5500 - 6000mL
What are the 4 steps of gas transport?
- ventilation of the lungs - diffusion in the lungs - perfusion in the lungs - diffusion in the tissues
What is V/Q?
- the ventilation-perfusion ratio - should be about 0.8 (more perfusion than ventilation)
What is the oxyhaemoglobin dissociation
- allows for more oxygen to be delivered to the cells when needed - right shift (reduced affinity) on increased temp, increased H+ encourages oxygen to detach from haemoglobin - left shift on decreased temp, decreased H+, increased CO encourages oxygen to remain linked to haemoglobin
What are the normal values for ABGs?
pH - 7.35 to 7.45 PaCO2 - 41 - 51 mmHg PaO2 - 80-100mmHg HCO3 - 22 - 26 mmol/L Base excess - +2.0 to -2.0 mmol/L SaO2 - 95-100%
Major lower respiratory disorders
Obstructive
- asthma
- Bronchiectasis
- COPD *emphysema * bronchitis
Restrictive
- acute respiratory distress syndrome (ARDS) Infections
- Pneumonia
Cancer
- Lung Cancer
Cystic Fibrosis (leads to mucus plugging, chronic inflammation and chronic infection)
What are the characteristics of obstructive pulmonary disease?
- airway obstruction that worsens with expiration - common clinical manifestations: dyspnoea and wheezing, decreased FEV1, chronic fatigue - mismatched V/Q ratio
What is asthma?
- hyper-responsive airways
- often reversible with treatment, but can become chronic inflammation of the airways
What is the pathophysiological pathway of asthma leading to respiratory failure?
What are the drug groups for asthma management?
- Relievers
* short or long-acting beta-agonists (aka adrenergic stimulants. eg. salbutamol, terbutaline)
* anticholinergics (bronchodilators; eg. Ipratropium, tiotropium bromide)
* theophyllines (aka mathylxanthines)
- controllers
* long-acting beta-agonists (eformoterol fumarate dehydrate, salmeterol xinafoate)
- preventers
* corticosteroids (eg ciclesonide, fluticasone propionate, budesonide)
* cromones (aka mast cell stabilisers; eg cromolyn sodium and nedocromil)
* leukotriene receptor agonists (montelukast)
* anti IgE antibody
What is the pathophysiological pathway for COPD?
Medication management of COPD?
- Broncho-dilators
- Indacaterol
- Cortico-steroids
- Anti-mucolytics
- Influenza vaccine
- Oxygen
What is restrictive pulmonary disease?
- Less common in Australia compared to obstructive
- Different pathology but many similar clinical manifestations
- Lung tissue compliance decreases
- Increased respiratory effort
- Decreased lung volume and tidal volume
- Different causes
- Intrinsic (asbestosis, acute respiratory distress syndrome)
- Extrinsic (neuromuscular diseases)
What is Acute Respiratory Distress Syndrome?
- A syndrome characterised by
- Acute lung inflammation
- diffuse alveolar-capillary disease
- Pulmonary oedema and severe hypoxaemia
- Often as a result of other serious disorders
- Sepsis,
- burns,
- pneumonia aspiration,
- overdose
- poisoning
- Due to oedema and collapsing alveoli, Lung compliance decreased and breathing effort increased
- Often escalates to body-wide inflammatory response and multi-organ failure
What is the pathophysiological pathway of ARDS?
Medications to treat ARDS:
- Oxygen
- Nitric oxide
- Artificial surfactant
What are the most likely reasons for lower airway infectious pulmonary diseases?
- immunocompromise
- unrelated medical problems
- post-surgery
- forced bedrest
- smoking
What is the pathophysiological pathway for pneumonia?
What are the main clinical manifestations of pneumonia?
Rapid onset of:
- fever
- chills
- either productive (reddish or purulent green) or dry cough
- dyspnoea, hypoxaemia
- adventitious breath sounds
What are the main medications used for pneumonia?
- Pneumococcal vaccination (prevent)
- Treat cause (antibiotics, antifungals)
- Broncho-dilators
- anticholinergic drugs
- antimucolytic
- Oxygen support
Medications for lung cancer
- Chemotherapy (Doxorubicin, vincristine)
- radiotherapy, surgery
- Broncho-dilators
- Analgesics
- Oxygen
What are the two primary variables used to determine lung volume and flow changes
- the forced expiratory volume in the first second of exhalation; abbreviated to FEV1
- the forced vital capacity (FVC), or the maximal amount of air that can be forcibly expelled from the lungs in one breath
- FEV1 / FVC ratio should be greater than 70%
What are the three types of ling receptors that send impulses from the lungs to the dorsal respiratory group?
- irritant receptors (cause bronchoconstriction, increase in ventilatory rate)
- stretch receptors (size and volume of the lungs)
- J-receptors (cause shallow breathing, hypotension, bradycardia)
What is forced expiratory volume (FEV1)?
The amount of air that can be forcibly exhaled in 1 second
What is forced vital capacity (FVC)?
The amount of air that can be exhaled forcefully and rapidly after maximum air intake
What is minute volume (MV)?
the total amount or volume of air breathed in 1 minute.
What are the two pressures normally present in the thoracic cavity?
- Intrapulmonary pressure - within the alveoli of the lings
- Intrapleural pressure - within the pleural space (always less than intrapulmonary pressure
What is the difference between chronic bronchitis and emphysema, the two diseases usually present in COPD?
Chronic bronchitis consists of airway inflammation and remodelling (hypersecretion of mucus and chronic productive cough) whereas emphysema is the destruction of alveolar tissue and decrease in elastic recoil.
Treatments for the respiratory symptoms of cystic fibrosis
- techniques to promote mucus clearance, such as:
- chest physical therapy
- positive pressure devices
- bronchodilators
- aerosolised DNase which liquefies mucus
- inhaled mucolytics such as hypertonic saline and mannitol
Types of lung cancer
- squamous cell carcinoma
- adenocarcinoma
- large cell carcinoma
- small cell carcinoma
Conditions caused by pulmonary alterations
- Pulmonary oedema (excess water in the lungs)
- Hypoxaemia (reduced oxygenation of arterial blood)
- Hypercapnia (increased carbon dioxide in the arterial blood)
- Acute respiratory failure
- Atelectasis (the collapse of lung tissue)
- Pneumothorax (the presence of air or gas in the pleural space)
- Pleural effusion (the presence of excess fluid in the pleural space)
- Empyema (infected pleural effusion) - the presence of pus in the pleural space
- Aspiration (the inhalation of fluid and solid particles into the lung)
Signs and symptoms of pulmonary alterations
- Dyspnoea
- Cough
- Hypoventilation and hyperventilation
- Abnormal breathing patterns
- Haemoptysis
- Cyanosis
Diagnostic tests for pneumonia
- history and physical examination
- Chest X-ray
- CT scan
- Sputum Gram stain
- Sputum culture and sensitivity
- Full blood count
- Serology testing
- Pulse oximetry
- Arterial blood gases
- Fibre-optic bronchoscopy
Common asthma triggers
- Environmental allergens (often small glycoproteins, e.g. dust mites, animal dander, pollen, fungi) Cigarette smoking
- Pollution
- irritants (fumes from volatile compounds, e.g. cleaning agents, glues, paints)
- Respiratory tract infections
- medications (aspirin, non-steroidal anti-inflammatory drugs, beta-blockers)
- Physical factors (exercise, changes in temperature)
- gastro-oesophageal reflux
- Emotional stress
- occupational exposure to organic compounds
- food additives
manifestations of acute asthma
- dyspnoea
- tachypnoea
- tachycardia
- chest tightness
- wheezing
- cough
- anxiety
Main pulmonary vascular disorders
- pulmonary embolism
- pulmonary hypertension
Primary causes of respiratory failure
- airway obstruction (eg laryngospasm, foreign body aspiration, airway oedema
- respiratory disease (eg asthma, COPD)
- neurological causes (eg spinal cord injury, poliomyelitis, Guillain-Barre syndrome, drug overdose, stroke)
- chest wall injury (eg flail chest, pneumothorax)
- alveolar disorders (eg. pneumonia, pneumonitis, COPD)
- pulmonary oedema (eg heart failure, ARDS, near-drowning)
- ventilation-perfusion mismatch (eg pulmonary embolism)
Conditions associated with the development of acute respiratory distress syndrome (ARDS)
- shock (eg haemorrhagic shock, septic shock)
- inhalation injuries (eg aspiration of gastric contents, smoke and toxic gases, near-drowning, oxygen toxicity
- infections (eg Gram-negative species, viral pneumonia, pneumocystis carinii)
- drug overdose (eg heroin, methadone, aspirin)
- trauma (eg burns, head injury, lung contusion, fat emboli)
- disseminated intravascular coagulation
- pancreatitis
- uraemia
- amniotic fluid and air emboli
- multiple transfusions
- open heart surgery with cardiopulmonary bypass
Indications for oxygen therapy
- Used primarily to treat hypoxia and hypoxaemia (oxygen deficiency in arterial blood)
- PaO2 less than 50mmHg may result in tissue hypoxia
- Conditions that may decrease PaO2 include airway obstruction, hypoventilation or high altitude
- Used as a carrier gas in anaesthetics
- Treatment of cyanosis, shock, severe haemorrhage, cardiac and respiratory arrest, coronary artery occlusion
adverse effects of oxygen administration
- Oxygen toxicity
- Exposure to 80% to 100% oxygen for prolonged periods
- Inflammatory response à destruction of the alveolar membrane
- Symptoms
- ache or burning behind the sternum
- respiratory distress with decreased vital capacity
- nausea and vomiting
- restlessness, tremors
- twitching
- paraesthesias
- convulsions
- a dry, hacking cough
Info on salbutamol for asthma
- Short acting β2 agonists
- Rapid onset of action
- 5-15 minutes onset
- 1-2 hours peak
- 3-6 hours duration
- Adverse Effects – tremor, palpitations, anxiety, restlessness, headaches, muscle cramps, hyperglycaemia, tachycardia.
- Adult dose – 1-2 inhalations (100mcg salbutamol per dose), second 1 minute after the first.
- Can also be given via nebuliser, orally or parenterally.
Info on Beclomethasone for asthma
- Corticosteroid
- Maintenance treatment and prophylaxis
- Peak plasma levels – 3-5 hours after admin
- Local adverse effects – dysphonia (changed voice), oropharyngeal candidiasis (oral thrush) and allergic reactions
- Not useful in acute attacks
- Typical adult dosage – 50-200mcg up to a max of 400mcg twice daily.
- May be up to 2000mcg daily in severe persistent asthma
Info for Salmeterol for asthma
- aka Serevent
- Long acting β2 agonist
- Half-life 6-12 hours administered BD or daily.
- Used in conjunction with inhaled corticosteroids
- Side effects – pharyngitis and upper respiratory tract infections and headache.
- Only be used when short or intermediate-acting drugs are unable to control the symptoms.
Info for combination drugs for asthma
- Combination of preventer (inhaled corticosteroid) and reliever/controller (long-acting β2 agonists).
- Regular treatment when both drugs appropriate not for relief of acute symptoms.
- Advantages – convenience, cost reduction, better control of asthma and regular use of low dose steroid.
- fluticasone and salmeterol (Seretide)
- budesonide and eformoterol (Symbicort).
Information for inhaled corticosteroids for asthma
- Useful in preventing asthma
- Decrease the degranulation of mast cells and have a role in the synthesis of inflammatory mediators and new antibodies.
- Administered via inhalation to reduce bronchial hyper-activity and minimise patho-physiological changes (oedema, excessive mucous)}Metered dose inhaler or nebuliser decreases incidence of systemic reactions.
- Beclomethasone, fluticasone and budesonide
- Does not act as a bronchodilator, may need to give bronchodilator first to increase the ability of corticosteroid to reach airways
information for systemic corticosteroids for asthma
- Used when inhaled medication cannot adequately control asthma
- Prednisolone – short course
- In an emergency can be given parenterally – IV hydrocortisone, dexamethasone
- Can cause systemic adverse events – adrenal suppression, growth suppression, altered deposition of muscle, fat, skin, hair and bone, ocular changes, infections, mineralocorticoid effects and psychological disturbances
What is an adrenal crisis?
- Prolonged use of corticosteroids suppresses the normal hypothalamic-pituitary axis.
- Leads to adrenal atrophy from lack of stimulation
- Sudden cessation of medication, extreme stress (MVA, surgical procedure, massive infection) → adrenal crisis
- Can result in → physiological exhaustion, hypotension, fluid shift, shock and even death.
- Treatment – massive infusion of replacement steroids, constant monitoring and life support measures.
Info on glucocorticoids
- Anti-inflammatory action
- Stabilise lysosomal membranes and prevent neutrophil movement
- Suppresses virtually all the vascular and cellular events in the inflammatory response including wound healing and repair
- Inhibit many more mediators than NSAIDs
- Immunosuppressant action
- Block production and release of cytokines and other mediators
- Interfere with integrated role of T and B lymphocytes, macrophages and monocytes
info on Mineralocorticoids
- Affect electrolyte levels and homeostasis
- Increase sodium reabsorption in renal tubules, leading to sodium and water retention and increase potassium excretion
Bronchodilators for COPD
- Via inhaler with spacer or nebuliser
- Salbutamol (short-acting β2 agonists)
- Indacaterol (long-acting β2 agonists) – only used in long term management of COPD and often combined with a corticosteroid
- Relax tight muscles
- Quick relief from symptoms
- No effect on inflammation
Inhaled corticosteroids for COPD
- Decrease inflammatory response
- Inhaled budesonide/fluticasone
- Slows respiratory decline
- Prone to chest (and other) infections
- Oral steroids may be required for severe exacerbation of symptoms
oxygen therapy for COPD
- Long term home oxygen
- ~ 18 hrs per day to permanent
- Meet certain criteria and requires a prescription
- Likely to not relieve (though may reduce) breathlessness but ensures oxygen to vital organs
- Demonstrated to reduce mortality
- Safety precautions
- Titrated to individual needs but often 2 LPM to 4 LPM
Key drug groups for respiration
◆ BRONCHODILATOR DRUGS:
✛ Anticholinergics (muscarinic antagonists):
long-acting: tiotropium, aclidinium, umeclidinium, glycopyrronium bromide (glycopyrrolate)
short-acting: ipratropium
✛ β-adrenoceptor agonists:
long-acting (controllers): formoterol (eformoterol), salmeterol, indacaterol
short-acting: salbutamol, terbutaline (DM 26.2)
✛ Methylxanthines: aminophylline, theophylline (DM 26.3)
◆ DRUGS FOR RESPIRATORY TRACT INFECTIONS:
✛ Antivirals: amantadine, neuraminidase inhibitors: zanamivir, oseltamivir
✛ Cough suppressants: codeine, pholcodine (DM 26.5)
✛ Decongestants: xylometazoline (DM 26.1)
✛ Drugs for influenza: vaccines (DM 26.6)
◆ DRUGS FOR RHINITIS: Antihistamines, nasal corticosteroids
◆ EXPECTORANTS: dilutents: normal saline, water; irritant expectorants: guaifenisin
◆ MEDICAL GASES: carbon dioxide, nitric oxide, nitrous oxide, oxygen
◆ MUCOLYTICS: dornase alfa, bromhexine, acetylcysteine
◆ PROPHYLACTIC ANTIASTHMA DRUGS (PREVENTERS):
✛ Cromones (cromolyns): sodium cromoglycate, nedocromil
✛ Inhaled (gluco)corticosteroids: beclometasone (DM 26.4), budesonide, fluticasone, ciclesonide
other drug groups
✛ Leukotriene-receptor antagonists: montelukast
5-lipoxygenase inhibitors: zileuton
monoclonal antibodies: omalizumab, mepolizumab
◆ PULMONARY SURFACTANTS: beractant, poractant alfa
What is the bicarbonate buffer equation?
CO2 + H2O ⇄ H2CO3 ⇄ HCO3− + H+
