Atelectasis (collapse)

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