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CHAPTER 58: Restrictive Disease of the Respiratory System 519

ground-glass opacifications or consolidation that may represent a treat- particularly when ground-glass infiltrates are identified on CT
able form of pneumonitis or alveolar hemorrhage. Appropriately excluded imaging. Mycobacterial infections should also be considered. The
from this practice are patients with progressive, end-stage disease incidence of tuberculosis is increased in patients with chronic intersti-
98
in whom outcome is invariably poor. 72,86 In these cases, a prospec- tial lung disease, particularly in those with silicosis. Atypical myco-
tive discussion and decision not to initiate resuscitative efforts should bacterial superinfection may also underlie clinical deterioration in
precede the anticipated terminal event. some cases. When fibrosis is associated with connective tissue disease
The results of several studies demonstrate the grim prognosis of or vasculitis, an acute deterioration may represent pneumonitis, cryp-
patients with IPF admitted to the ICU for acute respiratory failure togenic organizing pneumonia, or alveolar hemorrhage. Patients with
(ARF). Blivet and colleagues described the course of 15 patients diffuse alveolar opacifications not responsive to antibiotics or diuresis
admitted to the ICU with IPF and respiratory failure. Twelve patients should be considered for bronchoalveolar lavage or lung biopsy in
87
required intubation either at the time of admission or after failure of selected cases to confirm the diagnosis. 99,100
noninvasive ventilation; three patients received noninvasive ventila- When pneumothorax causes acute deterioration, chest tube reexpan-
tion only. Eleven patients died either from respiratory failure or septic sion is countered by low parenchymal compliance, occasionally mandating
shock. Four patients were discharged alive from the ICU, but two died high levels of negative pleural pressure for prolonged periods of time.
shortly thereafter. Stern and colleagues reported their experience in Acute right or left heart failure should also be considered in the dete-
23 patients with IPF requiring intubation for ARF. With the excep- riorating patient. Right ventricular ischemia or pulmonary embolism
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tion of one patient who received a single-lung transplant six hours may provoke right ventricular failure. Left-sided failure is difficult to
after intubation, all patients died while receiving mechanical ventila- establish without echocardiography or hemodynamic measurements
tion. Fumeaux and colleagues similarly reported 100% mortality in because bibasilar crackles are invariably present and jugular venous dis-
14 consecutive patients with IPF admitted to the ICU for mechanical tention may reflect isolated right ventricular dysfunction.
ventilation after a mean of 7.6 days. In the study by Saydain and If deterioration occurs over a period of weeks to months, progres-
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colleagues of 38 patients with IPF admitted to the ICU mainly for sive fibrosis, bronchogenic carcinoma, drug toxicity (including steroid
respiratory failure, ICU mortality was 43% and hospital mortality was myopathy), cor pulmonale, anemia, atypical mycobacterial infection,
61%. However, 92% of hospital survivors died a median of 2 months and left ventricular failure should be considered.
90
after discharge.
More recently, Rangappa and colleagues published a series of ■ OXYGEN THERAPY
24 patients with IPF admitted to the ICU with respiratory failure. Of Identification and correction of arterial hypoxemia are vital. We rec-
19 mechanically ventilated patients, 16 died in the ICU, six died in the ommend titration of supplemental oxygen until 90% oxyhemoglobin
hospital, and only two were discharged home. Mallick reported a sys- saturation is achieved. It is not unusual for patients with fibrosis to
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tematic review of nine studies describing 135 patients with IPF under- require higher flow rates than patients with chronic obstructive pul-
going mechanical ventilation in an ICU; aggregated ICU mortality was monary disease or asthma. Hypoxemia, in addition to its many other
87% with a 3-month postdischarge mortality reaching 94%. 92 adverse effects, causes hypoxic pulmonary vasoconstriction and may
Prognosis for non-IPF pulmonary fibrosis syndromes such as idio- precipitate right ventricular failure in patients with pre-existing pulmo-
pathic nonspecific interstitial pneumonia may be somewhat better than nary hypertension.
for IPF. 93
resolution computed tomography may predict prognosis in acute exacer- ■ CARDIOVASCULAR MANAGEMENT
The pattern and extent of parenchymal abnormalities on high-
bations of idiopathic pulmonary fibrosis. Diffuse and multifocal patterns Evaluation of shock in patients with pulmonary fibrosis is simi-
predict worse outcomes when compared with peripheral patterns. 94 lar to that described elsewhere in this text (see Chaps. 31 and 33).
■ DETECTING REVERSIBLE FEATURES Hypotension with cool and clammy extremities and a narrow pulse
pressure suggests inadequate cardiac output from hypovolemia, left
An acute change in clinical status may be caused by progression of the ventricular failure, cor pulmonale, pericardial tamponade, or valvular
underlying disease, although the differential diagnosis is quite broad heart disease. Hypotension with a warm and bounding circulation and
(Table 58-2). Frequently, a cause of ARF is not identified. Acute, a wide pulse pressure suggests sepsis; however, patients with pulmo-
88
68
clinically significant deteriorations of unidentifiable cause in patients nary hypertension may be unable to mount a hyperdynamic response
with underlying IPF have been termed acute exacerbations of IPF ; such to peripheral vasodilation. Adrenal insufficiency contributing to shock
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exacerbations portend a poor prognosis. Predisposing factors to acute should be excluded, particularly when corticosteroids have been used
96
exacerbations of IPF remain unclear. 97 for therapy.
bacteria; opportunistic infection is rare despite the widespread use ■ VENTILATOR MANAGEMENT
Pneumonia in IPF generally results from community-acquired
of immunosuppressive agents. However, Pneumocystis jiroveci Due to the extremely poor prognosis of patients with IPF who receive
82
pneumonia should be considered in immunosuppressed patients, intubation and mechanical ventilation, compassionate use of noninva-
sive ventilation may be considered for respiratory management in some
patients. 101,102 When deemed appropriate, intubation is indicated for
TABLE 58-2 Selected Causes of Deterioration in Patients With Pulmonary Fibrosis cardiopulmonary arrest, refractory hypoxemia, progressive ventilatory
failure, mental status changes, and shock. Once the decision to intubate
Progression of the underlying disease
has been made, the goals are to achieve adequate gas exchange and
Pneumonia avoid ventilator-induced lung injury. Although there are no controlled
Pulmonary embolism trials to guide specific recommendations, we advocate a lung protective
strategy similar to that recommended in the acute respiratory distress
Left ventricular failure
103
syndrome, particularly since patients with ILD are more suscep-
Cor pulmonale tible to barotrauma. To avoid excessive tidal volume excursions and
104
Aspiration alveolar overinflation, we use tidal volumes in the range of 6 to 7 mL/kg
Bronchospasm combined with respiratory rates of 20 to 30/min when ventilating
patients with pulmonary fibrosis. The goal is to maintain airway plateau
Pneumothorax pressures below 30 cm H O in an attempt to avoid overdistention beyond
2

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