MS UNIT 5 PT.2

Acute Respiratory Distress Syndrome

is a syndrome of diffuse alveolar damage resulting from direct or indirect lung injury

Acute Respiratory Distress Syndrome

It leads to increased capillary permeability, non-cardiogenic pulmonary edema, loss of surfactant, alveolar collapse (atelectasis), and refractory hypoxemia

refractory hypoxemia

hypoxemia that does not respond to supplemental oxygen

Direct Lung Injury

Aspiration of gastric contents, severe viral or bacterial pneumonia, thoracic trauma, pulmonary contusion, inhalation of toxic fumes, or near-drowning

Indirect Lung Injury

Systemic sepsis (most common cause), massive blood transfusion (TRALI), major burn injury, severe acute pancreatitis, hypovolemic shock, or fat/amniotic fluid embolism

Type II pneumocytes

In ARDS, Damage to ____ impairs surfactant production, leading to alveolar instability, widespread micro-atelectasis, and decreased lung compliance ("stiff lungs").

severe ventilation-perfusion (V/Q) mismatch and refractory hypoxemia

In ARDS, Blood flows past non-ventilated alveoli without picking up oxygen, causing _____

respiratory alkalosis

Early ABGs show ___ due to hyperventilation (PaCO2 < 35 mmHg)

respiratory acidosis

Early ABGs show respiratory alkalosis due to hyperventilation (PaCO2 < 35 mmHg). As respiratory muscle fatigue sets in, it shifts to ____

< 60

Severe hypoxemia (PaO2 ___mmHg) remains refractory to increasing FiO2 (decreased PaO2/FiO2 ratio)

Chest X-Ray/ CT Scan

Classically reveals bilateral, diffuse alveolar infiltrates ("ground-glass opacity" or "white-out" lung) without cardiomegaly.

< 18 mmHg

Pulmonary Artery Wedge Pressure (PAWP) normal value

Pulmonary Artery Wedge Pressure (PAWP)

it distinguish ARDS from cardiogenic pulmonary edema

Early Phase

what phase in ARDS: Rapid, shallow breathing (tachypnea), dyspnea, clear or scattered crackles, mild apprehension, and low oxygen saturation despite supplemental oxygen

Late/Progressive Phase

what phase in ARDS: Severe respiratory distress, intercostal retractions, central cyanosis, diaphoresis, confusion/lethargy due to hypoxia, and signs of secondary multi-organ dysfunction syndrome (MODS)

Low tidal volume strategy (4-8 mL/kg ideal body weight)

____ to prevent volutrauma/barotrauma, combined with Positive End-Expiratory Pressure (PEEP) to keep alveoli open

Positive End-Expiratory Pressure (PEEP)

: Low tidal volume strategy (4-8 mL/kg ideal body weight) to prevent volutrauma/barotrauma, combined with ____ to keep alveoli open.

Vasopressors (e.g., norepinephrine) and cautious fluid management (conservative fluid protocol)

used to maintain organ perfusion while avoiding worsening pulmonary edema

Broad-spectrum antibiotics

used for underlying sepsis

neuromuscular blocking agents (NMBAs)

used to optimize ventilator synchrony

sedatives

used for comfort

endotracheal intubation, tracheostomy

in ARDS, Surgical or invasive interventions include _____ for prolonged mechanical ventilation, placement of chest tubes for pneumothorax

Extracorporeal Membrane Oxygenation (ECMO)

used for refractory cases

endotracheal tube placement and cuff pressure

in ARDS, Monitor ____ for airway and ventilator management.

prone

for ARDS, Place the patient in a ___ position as ordered (often 12-16 hour/day) to improve ventilation-perfusion matching, recruit dorsal alveolar units, and enhance secretion drainage

12-16

for ARDS, Place the patient in a prone position as ordered (often ____ hour/day)

Ventilator-Associated Pneumonia (VAP)

for ARDS, Enforce strict infection control to prevent _____

head of bed elevated 30-45 degrees, oral care with chlorhexidine, daily sedation vacations

execute standard VAP bundles which include:

Pulmonary Embolism

The obstruction of one or more pulmonary arteries by a thrombus originating elsewhere in the venous system, most commonly from the deep veins of the lower extremities

Cor Pulmonale

Hypertrophy or dilation of the right ventricle resulting from altered structure or function of the lungs, secondary to pulmonary hypertension.

Acute Cor Pulmonale

____ frequently results from massive PE

Venous Stasis, Vessel Wall Injury, Hypercoagulability

Virchow’s Triad includes:

Venous Stasis

Prolonged immobility, surgery, obesity, advanced age, heart failure (Keogh).

Vessel Wall Injury

Trauma, orthopedic surgery, intravenous catheterization.

Hypercoagulability

Malignancy (Mehta), oral contraceptive use, pregnancy, hereditary coagulation disorder

Chronic Obstructive Pulmonary Disease, interstitial lung disease, recurrent PEs, severe chest wall deformities.

Cor Pulmonale causes:

right atrium and ventricle

A thrombus detaches from a deep vein, travels through the _____, and lodges in the pulmonary vascular bed (Black)

pulmonary vascular bed (Black)

A thrombus detaches from a deep vein, travels through the right atrium and ventricle, and lodges in the ____

serotonin, thromboxane A2

The physical barrier, combined with local release of neurohumoral substances (_____), causes severe pulmonary vasoconstriction

right ventricular workload (Keogh)

Elevated pulmonary vascular resistance increases _____

D-Dimer Test

Elevated levels indicate active clot formation and degradation (high sensitivity, non-specific)

Computed Tomography Pulmonary Angiography

Gold standard for rapid, definitive PE visualization

Ventilation-Perfusion (V/Q) Scan

Evaluates perfusion deficits in patients unable to receive IV contrast

Echocardiogram

Detects right ventricular strain, dilation, or acute Cor Pulmonale dynamics.

Electrocardiogram

Sinus tachycardia; right axis deviation, S1Q3T3 pattern, or right bundle branch block under massive RV strain.

compensatory tachypnea

In PE, Initial hypoxemia (PaO2 < 80 mmHg) and hypocapnia (PaCO2 < 35 mmHg) due to ____

hypocapnia

PaCO2 < 35 mmHg indicates ___

Sudden-onset dyspnea

most common pulmonary embolism manifestation

Distended neck veins (JVD), peripheral edema, hepatomegaly, right upper quadrant abdominal tenderness, S3/S4 gallop, and parasternal heave

Cor Pulmonale Specifics:

Immediate IV unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH)

to prevent clot expansion in PE

Systemic Alteplase (tPA)

it is for hemodynamically unstable ("massive") PE to dissolve the occluding thrombus

Catheter-Directed Embolectomy / Surgical Embolectomy

Reserved for massive PE when thrombolytics are contraindicated.

Inferior Vena Cava (IVC) Filter

Surgically placed to catch recurrent emboli in patients with high bleeding risk or recurrent clots despite anticoagulation

Unfractionated heparin (UFH); Warfarin

for PE, Monitor aPTT (for ____) or INR (for ____).

protamine sulfate and vitamin K

for PE, maintain ____ as antidotes

analgesics (e.g., morphine)

for PE, position comfortably and administer prescribed ____ to reduce anxiety and pleuritic pain, easing respiratory effort

placing pillows under knees or flexing knees sharply

for PE, what to avoid: