Class 22 review Flashcards
Antitussives
used with dry hacking, non-productive coughs from a common cold and cough due to allergy where
the cough interferes with rest and irritates the throat (NOT pneumonia, COPD, Asthma, or aspiration where the cough assists with airway clearance)
Antitussive MOA
dampen cough reflex
Antitussive Opioid
MOA: high efficacy, raise cough threshold in CNS, only requires a low dose
codeine – caution with allergy causing bronchoconstriction
Antitussive Non-Opioid
MOA: chemically similar to opioids and also acts in the CNS to raise cough threshold, not as high efficacy, but no risk of dependency
In OTC cold and flu medication, higher dose by prescription
Side effects – dizziness, drowsiness, GI upset
Expectorants
MOA: promote mucus secretion, making the mucus thinner and easier to remove by cough
Guaifenesin (Benylin) most effective OTC expectorant (higher doses by prescription)
Mucolytics
MOA: used to break down thick bronchial secretions – become thinner and easier to remove by
cough
Acetylcysteine (Mucomyst) – one of few available, inhaled, prescription only
Patients with cystic fibrosis, chronic bronchitis (COPD)
An infection of the lower respiratory tract results in…
an inflammatory response that leads to accumulation of exudate and fluid in the alveoli, affecting gas exchange. CONSOLIDATION occurs when air in the alveoli is replaced by exudate.
Mortality rate of a pulmonary embolus
Mortality of 30% untreated, 6-8% treated
The classic triad of symptoms of a patient presenting with a PE are
Dyspnea, chest pain and hemoptysis
Atelectasis
Incomplete expansion or collapse of alveoli, caused by hypoventilation, obstruction of the airways, or compression
Earliest sign of inadequate oxygenation
Change in behaviour
Influenza
• Onset abrupt; • Systemic symptoms: ◦ fever, myalgia, headache, • Sore throat, dry cough • Subsides in 7 – 10 days • Risk of pneumonia • Influenza vaccine • Antiviral in severe cases in high risk pop.
Cold
- Onset gradual and mild symptoms
- Tickling, irritation of throat
- Sneezing → copious nasal secretions
- Nasal congestion
- Elevated temperature
- Malaise, and headache
- Subsides in 3-4 days
Pneumonia
• Infection in the alveoli → inflammatory response (exudate, WBC, RBCs, Bacteria)
• Alveoli fill with fluid and exudate and affects gas exchange
• Consolidation occurs as exudate replaces air in alveoli
• LOBAR Pneumonia – most common
• Other types:
◦ Bronchopneumonia (scattered patches of infiltrates both lungs)
◦ Interstitial (infiltrates in alveolar walls between alveoli)
Who is at risk for pneumonia ?
• Smokers (4x more likely) • Alcohol & Substance Addictions • Influenza or other viral infection • Pre-existing lung disease (COPD) • Neurological disease • Renal/cardiac disease • Immune-suppressed or compromised patient ◦ Chemotherapy ◦ Organ transplant ◦ HIV • Very young (<5 yo); or Elderly (>85 yo) • The post-op patient (immobility, pain, procedure length) • Ventilated patient
Alveolar Hypoventilation
Causes both hypoxemia and hypercapnia
This also occurs in:
• Opioid use
• Chest wall injury/ pain
• Neuromuscular respiratory weakness
• Injury to respiratory center (tumour, trauma)
• Restrictive lung disease - any disorder that prevents the lungs from fully expanding e.g. pulmonary fibrosis
Pleurisy
Inflammation of the pleura
Mechanisms of Hypoxemia Shunt
Blood which arrives at the left ventricle without coming in contact with ventilating alveoli.
SpO2 >95%
Adequate unless the patient is hemodynamically unstable or has an O2 unloading problem
> 70 mmHg
SpO2 90%
Adequate in almost all patients. Values are at a steep part of the oxygen-hemoglobin dissociation curve. Oxygenation is adequate, but the margin of error is less than for higher values
60 mmHg
SpO2 88%
Adequate for patients with chronic hypoxemia if no cardiac problems occur. These values are also used as criteria for the prescription of continuous O2 therapy
55 mmHg
SpO2 75%
Inadequate but may be acceptable on a short-term basis if the patient also has CO2 retention. O2 therapy at a low concentration (24-28%) will gradually increase the PaO2. Monitoring dysthymias is necessary
40 mmHg
SpO2 <75%
Inadequate. Tissue hypoxia and cardiac dysrhythmias can be expected
< 40 mmHg
Is oxygenation shift to the right a good thing?
It is a good thing. Hemoglobin will release oxygen very easily and quickly to try and oxygenate the tissues.
Antibiotics used to treat pneumonia (children)
Strep pneumoniae; Pencillins (amoxicillin)
Antibiotics used to treat pneumonia (youth & young adults)
Chalmydia pneumoniae; Atypical microbes; Macrolides (azithromycin) or Tetracycline (doxycycline)
Antibiotics used to treat pneumonia (older adults)
Strep pneumoniae; Penicillins, Cephalosporins (3rd generation)
Antibiotics used to treat pneumonia (adults with chronic lung infections)
some resistant strains; Fluoroquinolones (levofloxacin)
Complications of pneumonia
Lung • Atelectasis • Pleural effusion • Empyema • Pleurisy • Lung abscess
Other systems • Pericarditis • Bacteremia → Sepsis • Meningitis • Endocarditis
Pleural Effusion & Empyema & Hemothorax
Abnormal collection of fluid in the pleural cavity
• Normally fluid enters the pleural cavity through the capillaries & is removed by lymph
• Excess fluid formation or decreased removal can cause collection
◦ Bacterial pneumonia
◦ Viral infection
◦ Pulmonary infarction
◦ Malignancy
◦ Empyema: pus
◦ Hemothorax: blood
Flail Chest
- Multiple rib fractures cause instability of the chest wall
- Damaged area (flail) moves paradoxically to the intact portion of the chest
- Inadequate ventilation
Pneumothorax
- Caused by air (or another gas) in the pleural cavity resulting in collapse of all or part of the lung
- If air entires the pleural cavity and equalizes the pressure, and the lungs collapse immediately (compression atelectasis)
Closed Pneumothorax
- Occurs when air enters the pleural cavity directly from the airways
- Simple or spontaneous pneumothorax is idiopathic and caused by a tear or rupture on the surface of a lung that allows air to reach the cavity through a bronchus
- Secondary pneumothorax is caused by rupture of an emphysematous bleb, erosion of a tumour, or cavitation through the visceral pleura
- The involved area of lung collapses by recoil, and the leak seals with collapse
- The mediastinum shifts toward the affected lung since the pleura vacuum is partially preserved
Open Pneumothorax
• Occurs when air enters the pleural cavity through an opening in the chest (ie. traumatic wound or surgery) causing immediate atelectasis
• Sucking wound describes a large opening in the chest wall in which the sound of air moving in and out makes a sucking sound
• During inspiration, mediastinum shifts toward the unaffected side and limits chest expansion. The mediastinum shifts toward affected side during expiration, and impairs venous return to the heart
Moves side to side
Tension Pneumothorax
- Most serious form of pneumothorax. Can be open or closed
- Characterized by one-way movement of air caused by a flap of damaged tissue that allows air to move into the pleural cavity during inspiration, but seals off the opening during expiration, preventing the outflow of air
- Causes increasing pressure in cavity, leading to widespread compression atelectasis
- Pressure pushes on mediastinum and displaces the heart while compressing the vena cava and unaffected lung. This results in decreased venous return and gas exchange. Severe hypoxia and respiratory distress develop quickly
Pneumothorax Clinical Picture
• Hypoxemia:
◦ decreased ventilation
◦ V/Q mismatch
◦ Mild in closed, moderate in open, severe in tension.
• Systemic signs and symptoms: tachycardia, anxiety, and pallor.
• Atelectasis
• Dyspnea, cough, and chest pain.
• Decreased breath sounds on affected side.
• Unequal lung expansion and mediastinal shift.
• Hypotension and shock caused by decreased venous return (especially in tension pneumothorax).
Pulmonary edema
An abnormal accumulation of fluid in the alveoli and the interstitial spaces of the lungs
Pulmonary embolism
Blockage of pulmonary arteries by a thrombus, fat or air embolus, or tumour tissue
Pulmonary embolism risk factors
immobility, recent surgery, history of DVT, malignancy, obesity, oral contraceptives, hormone therapy, smoking, prolonged air travel, heart failure, pregnancy and clotting disorders
Pulmonary embolism Manifestations
- Classic triad – dyspnea, chest pain, hemoptysis (20% presentation)
- Mild to mod hypoxemia
- Small emboli may be asymptomatic
- Massive emboli may cause decreased BP, pallor, severe dyspnea and hypoxemia
- Cough, crackles, fever, altered mentation, tachycardia
- Pleural friction rub
- May lead to pulmonary hypertension (massive or many recurrent)
Pulmonary embolism Diagnostic Studies and Tx
- Spiral CT Scan with IV contrast media to visualize blood vessels
- VQ Scan if cannot have contrast media (dye)
- Pulmonary angiography
- D-dimer, aPTT/INR
- ABG
- Supplemental oxygen – possible intubation
- Anticoagulants or fibrinolytics
- Limited activity
- Opioids for pain
