ATELECTASIS (COLLAPSE)
RESPIRATORY SYSTEM
ATELECTASIS
• Defined as the – “Collapse of pulmonary parenchyma”– Loss of lung volume
• Caused by inadequate expansion of airspaces.
• Results in shunting of inadequately oxygenated blood from pulmonary arteries into veins
• Giving rise to a ventilation-perfusion imbalance and hypoxia.
ATELECTASIS
• Could be due to – Incomplete expansion of a lung or part of a lung
in the newborn
• Primary atelectasis OR Neonatal atelectasis
– The collapse of previously inflated lung
• Secondary atelectasis OR Acquired atelectasis
ATELECTASIS Secondary atelectasis / Acquired atelectasis
According to the underlying mechanism
Three forms1. Resorption Atelectasis 2. Compression Atelectasis 3. Contraction Atelectasis
ATELECTASIS
• Resorption Atelectasis
RESORPTION ATELECTASIS • Due to obstruction that prevents air from
reaching distal airways.
• Air already present gradually absorbed- alveolar collapse follows.
• Depending on the level of obstruction, –an entire lung, –a complete lobe, –or one or more segments may be involved.
RESORPTION ATELECTASIS• Common cause; obstruction of a bronchus
by a mucous or mucopurulent plug in; –Postoperative states–Bronchial asthma–Bronchiectasis–Chronic bronchitis
–Or the aspiration of foreign bodies, particularly in children.
COMPRESSION ATELECTASIS
COMPRESSION ATELECTASIS; Also c/a passive or relaxation atelectasis
Pleural effusions:–congestive heart failure (CHF), neoplastic
effusions, tuberculosis• Basal atelectasis; resulting from the
elevated position of the diaphragm in;• bedridden patients, patients with ascites,
and patients during and after surgery.
CONTRACTION ATELECTASIS
CONTRACTION ATELECTASIS
–Local or generalized fibrotic changes in the lung or pleura may prevent full expansion
ATELECTASIS
• Atelectasis (except that caused by contraction)– is potentially reversible due to collapse
lung parenchyma can be re-expanded
–and should be treated promptly to prevent hypoxemia and superimposed infection of the collapsed lung.
Pulmonary Edema
Left Heart Failure andPulmonary Edema
• LVF occurs when the left ventricle fails to function as an effective forward pump, causing a back-pressure of blood into the pulmonary circulation
• May be caused by a variety of forms of heart disease including ischemic, valvular, and hypertensive heart disease
• Untreated, significant LVF culminates in pulmonary edema
Left Heart Failure andPulmonary Edema
• Signs and symptoms– Severe respiratory distress– Severe apprehension, agitation, confusion– Cyanosis (if severe)– Diaphoresis– Adventitious lung sounds– JVD– Abnormal vital signs
Left Heart Failure andPulmonary Edema
• Signs and symptoms– Severe respiratory distress– Severe apprehension, agitation, confusion– Cyanosis (if severe)– Diaphoresis– Adventitious lung sounds– JVD– Abnormal vital signs
Acute Pulmonary Edema
• May be CARDIAC or NON-CARDIAC in origin.• Results from conditions such as:
– Increased pulmonary capillary pressure– Increased pulmonary capillary permeability– Decreased oncotic pressure– Lymphatic insufficiency– mixed or unknown mechanisms