Critical Care Nursing Theory
ARDS
Acute Respiratory Distress Syndrome (ARDS)
Acute respiratory distress syndrome (ARDS) represents a complex clinical
syndrome (rather than a single disease process) and carries a high risk of
mortality.
ARDS was first described in 1967 and was termed adult (rather than acute)
respiratory distress syndrome because of a misconception that the syndrome
occurred only in adults
Diagnostic criteria for ARDS have been hard to define because ARDS is at
the extreme end of a continuum of acute, hypoxic lung injury resulting in
acute respiratory failure.
Acute respiratory distress syndrome (ARDS)
Definition: Is a sudden and progressive form of acute respiratory failure in
which the alveolar capillary membrane becomes damaged and more
permeable to intravascular fluid.
The Alveoli fill with fluid, resulting in severe dyspnea, hypoxemia
refractory to supplemental O2, reduced lung compliance, and diffuse
pulmonary infiltrates.
ARDS is a serious reaction to various forms of injuries to the lung.
It is characterized by inflammation of the lung parenchyma leading to
impaired gas exchange with concomitant systemic release of inflammatory
mediators causing inflammation, hypoxemia and
frequently
resulting
in multiple organ failure.
This condition is often fatal, usually requiring mechanical ventilation and
admission to an intensive care unit.
A less severe form is called acute lung injury (ALI).
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
Risk Factors for (ARDS)
PATHOPHYSIOLOGY
The pathological pulmonary alterations of ARDS are directly related to a
cascade of events resulting from release of cellular and biochemical
mediators.
The activation, interactions, and multisystem actions of biological mediators
are extremely complex.
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
Dr. Abdul-Monim Batiha
ARDS
Assistant Professor Of Critical Care
3
Critical Care Nursing Theory
ARDS
Stages of Acute Respiratory Distress Syndrome
Stage 1 (first 12 hr):
Normal chest x-ray, Dyspnea, tachypnea,
Pathological Change: Neutrophil sequestration, no evidence of cellular
damage.
Stage 2 (24 hr):
Patchy alveolar infiltrate, primarily in dependent lung areas; normal heart
size, Dyspnea, tachypnea, cyanosis, tachycardia, coarse crackles,
Pathological Change: Neutrophil infiltration, vascular congestion, fibrin
strands, increased interstitial and alveolar edema
Stage 3 (2–10 days):
Diffuse alveolar infiltrates, possibly air bronchograms, decreased lung
volume, normal heart size
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
Systemic inflammatory response syndrome (SIRS) presentation
Stage 4 (>10 days):
Persistent infiltrates, new pneumonic infiltrates, recurrent pneumothorax
Multiple organ involvement, difficulty maintaining adequate oxygenation,
sepsis, pneumonia
Systemic Inflammatory Response Syndrome:
Systemic inflammatory response syndrome (SIRS) describes the
inflammatory response occurring throughout the body as a result of some
systemic insult.
Most patients with ARDS manifest the symptoms that define SIRS.
Systemic Inflammatory Response Syndrome (SIRS) Criteria
SIRS is manifested by two or more of the following:
■ Temperature greater than (38°C) or less than (36°C)
■ Heart rate greater than 90 beats/minute
■ Respiratory rate greater than 20 breaths/minute or an arterial carbon
dioxide tension (PaCO2) less than 32 mm Hg
■ White blood cell count greater than 12,000 cells/mm3 or less than 4,000
cells/mm3 OR more than 10% immature (band) forms
Integrated Assessment of the Patient with (ARDS)
Stage 1 (first 12 hr)
Physical Examination
• Restlessness, dyspnea, tachypnea,
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
• Moderate to extensive use of accessory respiratory muscles
Diagnostic Test Results
• ABG: Respiratory alkalosis
• CXR: No radiographic changes
• Chemistry: Blood results may vary depending on precipitating cause (e.g.,
elevated white blood cell count, changes in hemoglobin)
• Hemodynamics: Elevated PAP, normal or low PAWP
Stage 3 (2–10 days)
Physical Examination
• Decreased air entry bilaterally
• Impaired responsiveness (may be related to sedation necessary to maintain
mechanical ventilation)
• Decreased gut motility
• Generalized edema
• Poor skin integrity and breakdown
Diagnostic Test Results:
• ABG: Worsening hypoxemia
• CXR: Air bronchograms, decreased lung volumes
• Chemistry: Signs of other organ involvement: decreased platelets and
hemoglobin, increased white blood cell count, abnormal clotting factors
• Hemodynamics: Unchanged or becoming increasingly worse
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
Stage 4 (>10 days)
Physical Examination:
• Symptoms of MODS, including decreased urine output, poor gastric
motility, symptoms of impaired coagulation
OR
• Single-system involvement of the respiratory system with gradual
improvement over time
Diagnostic Test Results:
• ABG: Worsening hypoxemia and hypercapnia
• CXR: Air bronchograms, pneumonthoraces
• Chemistry: Persistent signs of other organ
involvement: decreased platelets and hemoglobin,
increased white blood cell count, abnormal clotting factors
• Hemodynamics: Unchanged or becoming increasingly
worse
Comparison of Acute Lung Injury (ALI)
and Acute Respiratory Distress Syndrome (ARDS)
Criterion
PaO2:FIO2
regardless of
level
ALI
ratio, Less than 300
PEEP
Chest x-ray
Pulmonary
wedge
pressure
Bilateral infiltrates
ARDS
Less than 200
Bilateral infiltrates
artery Less than 18 mm Hg or Less than 18 mm Hg or
no indication
no indication indication
of
left
atrial
hypertension
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
 Hyopxemia and PaO2/FiO2 ratio below 200 (e.g., 80/0.8=100)
despite increased FiO2 by mask, cannula, or endotracheal tube are the
hall marks of ARDS.
NURSING ALERT
The treatment for ARDS is aimed at symptom management, but the
underlying cause must be treated or the ARDS will not resolve. Supportive
measures will assist the patient while the underlying cause is being treated.
MANAGEMENT
1. OXYGEN DELIVERY
Oxygen delivery is determined by hemoglobin, Recent studies on
transfusion requirements indicate that values of approximately 8.0 g/dL are
sufficient for critically ill patients, except for those with cardiac disease.
Therefore, transfusion to maintain normal hemoglobin is no longer accepted
therapy and should be discouraged
Therapies to optimize cardiac output are directed toward enhancing preload
and contractility and normalizing afterload.
Fluid administration to ensure adequate intravascular volume and optimize
preload is important before other interventions are initiated.
(PAWP) should be maintained at greater than 12 mm Hg and breath sounds
and ABGs closely monitored during fluid administration.
Positive inotropic agents, such as dopamine or dobutamine, are used to
enhance contractility and increase cardiac output.
Vasoconstrictors, such as norepinephrine, may be added to the therapies to
counteract the SIRS induced vasodilation
2. MECHANICAL VENTILATION
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
use of the lowest fraction of inspired oxygen (FIO2) to achieve adequate
oxygenation and use of small tidal volumes (<6 mL/kg) to minimize airway
pressures, thus preventing or reducing lung damage (barotrauma and
volutrauma) while maintaining the PaCO2 within a relatively normal range
PEEP prevents collapse and opens alveolar sacs, allowing diffusion of gases
across the alveolar–capillary membrane.
Recommended values for PEEP are 10 to 15 cm H2O,
Inverse ratio ventilation is another strategy thought to improve alveolar
recruitment
Reversal of the normal inspiratory:expiratory ratio (I:E ratio) to 2:1 or 3:1
prolongs inspiration time, preventing complete exhalation.
This increased end-expiratory volume creates auto-PEEP (intrinsic PEEP)
that is added to the applied extrinsic PEEP
3. EXTRACORPOREAL LUNG-ASSIST TECHNOLOGY
Extracorporeal lung-assist technology involves the use of large vascular
cannulas to remove blood from the patient.
A pumping device and circuit circulate the blood, and one or two “artificial
lungs” remove carbon dioxide and oxygenate the blood.
4. POSITIONING
Frequent position change is well established as a means to prevent and
reverse atelectasis and facilitate removal of secretions from the airways.
Although not a treatment for ARDS, turning a patient side to side, having
the patient sit upright, and using the Trendelenburg position for postural
drainage are necessary interventions to prevent worsening of respiratory
failure due to atelectasis and pneumonia.
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
Continuous lateral rotation using a kinetic therapy bed turns patients slowly
60 degrees to each side over 11 minutes and is useful to enhance secretion
removal
Prone positioning, in the patient’s bed improves pulmonary gas exchange,
facilitates pulmonary drainage in the dorsal lung regions, and aids resolution
of consolidated dependent alveoli (in the supine position), particularly in the
dorsal lung regions.
Pharmacological Therapy
Most of the pharmacological agents used in the ARDS population are
supportive.
Antibiotic therapy is appropriate in the presence of a known microorganism
but should not be used prophylactically.
Bronchodilators and mucolytics are useful in ARDS to assist in maintaining
airway patency and reducing the inflammatory reaction and accumulation of
secretions in the airways.
Exogenous surfactant replacement therapy has been used for several years in
neonates with hyaline membrane disease to decrease alveolar surface tension
and facilitate the maintenance of open alveoli.
Pharmacological Therapy
The use of corticosteroids to decrease the inflammatory response in late
stages of ARDS is regaining popularity with recent case studies and one
randomized, controlled trial supporting low doses in the 7- to 10-day range
of ARDS
Effective use of sedation to promote comfort and reduce respiratory effort,
thus decreasing oxygen demand, is an important consideration for nurses
dealing with patients with ARDS
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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Critical Care Nursing Theory
ARDS
Nutritional Support
Adequate nutrition should be initiated early and maintained, because
nutrition plays an active therapeutic role in recovery from critical illness.
Nursing Interventions
Care is similar to patient with respiratory failure
Dr. Abdul-Monim Batiha
Assistant Professor Of Critical Care
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