Comprehensive Respiratory System and Critical Care Topics

What is the primary function of the respiratory system?

To facilitate gas exchange.

What are the three main steps involved in gas exchange?

Ventilation, diffusion, and transport.

What occurs during ventilation?

The mechanical act of breathing brings oxygen into the lungs and expels carbon dioxide.

What happens during diffusion in the alveoli?

Oxygen diffuses into the blood and binds to hemoglobin, while carbon dioxide diffuses from the blood into the alveoli.

How does oxygenated blood reach the body's tissues?

It travels to the left side of the heart and is pumped via the systemic arterial system.

What is the significance of pulse oximetry (SpO2) in respiratory assessment?

It measures the degree of oxygen saturation in hemoglobin non-invasively.

What are arterial blood gases (ABGs) used for?

To assess gas exchange and acid-base balance.

What does a chest X-ray (CXR) help identify?

Abnormalities in the lungs such as infiltrates or consolidation.

What is Acute Respiratory Failure (ARF)?

A state of altered gas exchange where the respiratory system fails to maintain adequate oxygenation or carbon dioxide elimination.

What characterizes Type I ARF?

Low arterial oxygen levels (low PaO2) with normal or low carbon dioxide levels (PaCO2).

What characterizes Type II ARF?

High arterial carbon dioxide levels (high PaCO2), often seen in conditions like COPD.

What are common neurologic signs of ARF?

Mental status changes such as anxiety, restlessness, confusion, and lethargy.

What is the primary goal of managing ARF?

To maintain a patent airway and optimize oxygen delivery.

What is the role of bronchodilators in ARF management?

To open the airway, e.g., Albuterol.

What is Acute Respiratory Distress Syndrome (ARDS)?

A severe form of acute lung injury characterized by non-cardiac pulmonary edema and disruption of the alveolar-capillary membrane.

What are direct causes of ARDS?

Aspiration, near drowning, toxic inhalation, pneumonia, and thoracic radiation.

What are the indirect causes of ARDS?

Sepsis, Cardiopulmonary bypass, Severe pancreatitis, Embolism, Disseminated intravascular coagulation (DIC), Shock states.

What happens during the exudative phase of ARDS?

• Injury to pulmonary capillaries → increased permeability and fluid leakage into the lungs → interstitial and alveolar edema → impaired surfactant production

• microthrombi develops → pulmonary hypertension

What is the outcome of exudative phase of ARDS?

intrapulmonary shunting, V/Q mismatching, and decreased lung compliance due to atelectasis (alveolar collapse).

What occurs in the fibroproliferative phase of ARDS?

• The alveoli become enlarged and scarred, decreasing lung compliance and impairing gas exchange.

• pulmonary hypertension persists

What is the outcome of fibroproliferative phase of ARDS?

severe impairment in gas exchange leads to further hypoxemia that becomes refractory (unresponsive) to supplemental oxygen.

What is the resolution phase of ARDS?

Recovery that involves the restoration of the alveoli, which can take several weeks.

What is the significance of assessing lung sounds during a respiratory assessment?

To identify clear or adventitious (abnormal) sounds indicating potential issues.

What does increased work of breathing (WOB) indicate?

It suggests respiratory distress or difficulty in breathing.

What is the importance of monitoring skin color in respiratory assessment?

To identify signs of oxygenation issues, such as cyanosis.

What is the typical clinical presentation of Type I ARF?

• initially present with tachypnea (rapid breathing) and increased tidal volume.

• As the condition worsens and failure ensues, respirations may become shallow with a decreased rate.

• Use of accessory muscles and shortness of breath (SOB) are common, with patients sometimes adopting a tripod position

What is the role of alveolar macrophages in lung recovery?

They remove cellular debris and scar tissue.

What may be considered if a patient does not recover from lung injury?

End-of-life care.

What happens during Phase 1 of lung injury?

Initial injury reduces blood flow; platelets aggregate and release inflammatory mediators.

What occurs in Phase 2 of the pathophysiological progression of lung injury?

Inflammatory substances damage the alveolar-capillary membrane, increasing permeability.

What is the consequence of increased permeability in Phase 3?

Proteins and fluids leak out, increasing interstitial osmotic pressure and causing pulmonary edema.

What occurs in Phase 4 of lung injury?

Fluid and decreased blood flow damage surfactant, leading to alveolar collapse and impaired gas exchange.

What happens in Phase 5 regarding gas exchange?

Sufficient oxygen cannot cross the damaged alveolar-capillary membrane, leading to decreased blood oxygen levels.

What is the outcome of worsening pulmonary edema in Phase 6?

Inflammation leads to fibrosis, further impeding gas exchange.

What are the clinical signs of early-stage lung injury?

Tachypnea, restlessness, normal PaO2 and CXR, and clear lung sounds.

What clinical signs indicate late-stage lung injury?

Use of accessory muscles, crackles, agitation, hyperventilation, and infiltrates on CXR.

What is a key management strategy for ARDS?

Mechanical ventilation with careful management of tidal volume and PEEP.

What pharmacological interventions are used in ARDS management?

Bronchodilators, sedatives, analgesics, and neuromuscular blocking agents.

What positioning technique is effective for maximizing oxygenation in ARDS?

Prone positioning.

What is pneumonia?

acute inflammation of the lung tissue caused by an infection

Types of pneumonia

Community-Acquired (CAP), Hospital-Associated (HAP), Ventilator-Associated (VAP), and Aspiration Pneumonia.

Pneumonia pathophysiology

Microorganisms accumulate in the lower respiratory tract and overwhelm the patient's normal defense mechanisms.

What are common risk factors for pneumonia?

ETOH abuse, COPD, comorbidities, impaired swallowing, tube feedings, smoking, diabetes, immunocompromised status, advanced age, and use of ventilators.

What are the assessment findings for pneumonia?

• Cough, dyspnea, tachypnea, abnormal breath sounds

• chest pain, fever, confusion, and loss of appetite.

What are the diagnostic tools for pneumonia?

CXR, bronchoscopy, complete blood count (CBC), blood cultures, sputum analysis, chemistry panel, and ABGs.

What is nursing management for pneumonia?

• O2 therapy

• Antibiotics, Bronchodilators

• Positioning and suctioning prn

• Chest Physiotherapy (CPT)

• Adequate rest and recovery

• Monitoring for complications, especially ARF

• Comfort and support

• For patients on tube feedings, checking residuals is important.

What is the most common cause of pulmonary embolism?

A thrombotic embolus originating from a deep vein thrombosis (DVT).

What are the risk factors of pulmonary embolism?

• DVTs, venous stasis, immobility

• Atrial fibrillation (AFib)

• Injury to the endothelium (from infection or atherosclerosis)

• Hypercoagulability

• Surgery

• Cancers

• Trauma

• Pregnancy

What are the clinical signs of pulmonary embolism?

• Tachycardia, chest pain

• tachypnea, dyspnea, apprehension, cough, rales

• fever, signs of DVT, and hemoptysis.

What are the diagnostics of pulmonary embolism?

ABGs, D-dimer (especially with massive clotting), ECG, CXR, echocardiogram, CT scan, V/Q scan, pulmonary angiogram, and DVT studies.

What is the purpose of a V/Q scan in diagnosing PE?

To assess the balance between ventilation and perfusion in the lungs.

Normally, V/Q ratio is

balanced (V ≈ Q).

If ventilation exceeds blood flow (V > Q)

• the ratio is >1.

• This occurs in PE where an area of the lung is ventilated but not perfused due to the clot.

If blood flow exceeds ventilation (V < Q)

the ratio is <1.

What is the primary treatment for pulmonary embolism?

Oxygen support and anticoagulants (heparin drip followed by a "clot buster" (thrombolytic))

What are some supportive measures for pulmonary embolism?

Bronchodilators, sedatives/analgesics, fluids, and positioning.

what interventions/tools may be used for pulmonary embolisms?

• A Greenfield filter may be placed to catch clots.

• Surgical embolectomy is a last resort.

What should you monitor for a pt w/ pulmonary embolism?

Patients must be watched closely for signs of bleeding.

What is a common mechanical prophylaxis method to prevent PE?

Compression stockings and pneumatic compression boots.

What is the significance of checking residuals in patients on tube feedings?

To prevent aspiration and ensure adequate nutrition.