Page 639 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

458 PART 4: Pulmonary Disorders

APPROACH TO TREATMENT OF PATIENTS TABLE 52-5 Treatable Precipitating Causes of Acute Lung Injury (ALI) and
WITH ALI AND ARDS Acute Respiratory Distress Syndrome (ARDS)
■ TREAT THE PRECIPITATING CAUSE OF ALI AND ARDS Infectious etiologies

AND OTHER SERIOUS COMORBIDITIES Bacterial or other sepsis responsive to antimicrobial therapy
A key early step in treating patients with ALI and ARDS is to identify and Diffuse bacterial pneumonias (eg, Legionella species)
treat the precipitating cause or causes of the ALI and ARDS as well as any Diffuse viral pneumonias (eg, cytomegalovirus, influenza A)
other serious and life-threatening comorbidities (Fig. 52-5). The ventila- Diffuse fungal pneumonias (eg, Candida and Cryptococcus species)
tory and other supportive management of ALI and ARDS is inadequate Pneumocystis jiroveci (carinii) pneumonia
if not accompanied by aggressive attempts at diagnosis and treatment
of the precipitating cause(s) (Table 52-2). Because ARDS is a syndrome Other diffuse lung infections (eg, miliary tuberculosis)
based on nonspecific radiographic and physiologic criteria (Table 52-1), Noninfectious etiologies
making the diagnosis of ALI or ARDS is not equivalent to diagnosing the Diffuse alveolar hemorrhage post-bone marrow transplant
patient’s underlying problem. Not appreciating this seemingly obvious fact
will delay diagnostic procedures in these patients and may delay therapy Diffuse alveolar hemorrhage due to vasculitis (eg, Goodpasture syndrome)
of a potentially treatable underlying disorder (Table 52-5). Acute eosinophilic pneumonia
For example, although appropriate supportive therapy may transiently Lupus pneumonitis
stabilize a patient with ARDS due to sepsis from an abdominal abscess, if
clinicians delay performing diagnostic tests such as abdominal CT scan Toxic drug reactions (eg, aspirin, nitrofurantoin)
or ultrasonography of the biliary tract in a timely manner, the underlying
source of sepsis will go undiagnosed and the patient will eventually
patients with ALI or ARDS associated with severe sepsis or septic shock ■ VENTILATOR MANAGEMENT OF RESPIRATORY ABNORMALITIES
deteriorate. Likewise, the timely start of empiric antimicrobial therapy in
is as important as a timely diagnostic workup (see Chaps. 61 and 62). Maintaining Adequate Arterial Oxygenation: The hallmark respiratory
Finally, if the precipitating cause of ALI and ARDS is unclear, one should abnormality of ALI and ARDS is hypoxemia that is resistant to oxygen
consider performing early fiberoptic bronchoscopy to obtain bronchoal- therapy. This is due to the presence of a large right-to-left intrapulmo-
veolar lavage for cytologic and microbiologic analyses, or in selected nary shunt arising from fluid-filled and collapsed alveoli (see Fig. 52-1).
cases, surgical lung biopsy. Maintaining adequate arterial oxygenation is a goal given high priority by

Patient at risk
to develop ARDS
(Predisposing condition present)

Minimize risk for ALI development
- Head of bed > 30° to prevent aspiration
- Minimize transfusions
- Use low tidal volumes (lung-protective ventilation
strategy) to minimize ventilator induced lung injury

Patient develops ARDS

Treat precipitating cause(s) of ARDS and other serious
comorbidities
Provide best-evidence supportive care

Use lung-protective ventilation
(see Table 52-9)

Consider adjunct therapies (see Table 52-12)
Consider salvage therapies in patients with severe,
refractory ARDS (see Table 52-13)

Rehabilitation
Death and
recovery
FIGURE 52-5. Schematic summary of approach to patients at risk for ARDS development and treatment of patients with ARDS.

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