Page 143 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 15: Long-Term Outcomes After Critical Illness 109

Sepsis/SIRS
Microvascular disruption
Endotoxin-induced mitochondrial
dysfunction
Eicosanoids/cytokines/reactive O /NO
2
Hyperglycemia Drugs
Mitochondrial ICU-Acquired Weakness NMB
dysfunction Aminoglycosides
Assymmetric Corticosteroids
dimethylarginine
Proinflammatory
transcription Immobility
IL-1, IL-6, TNF-
Ubiquitin proteosome pathway FIGURE 15-4. Heterotopic ossification affecting the medial aspect of the right knee in
an ARDS patient.
FIGURE 15-3. Pathophysiology of ICU-acquired weakness. (Data from Pustavoitau A,
Stevens RD. Mechanisms of neurologic failure in critical illness. Crit Care Clin. 2008 Jan;24(1):1-24.)

of cosmetic changes that have been linked to emotional outcomes, social
isolation, and sexual dysfunction (Fig. 15-3).
■ PULMONARY FUNCTION ABNORMALITIES

Many ARDS survivors have persistent pulmonary function impairments
that are typically mild restrictive changes and an associated reduction
in diffusion capacity. Orme and colleagues reported that ARDS sur-
1,78
vivors had abnormal pulmonary function associated with decreased
HRQoL 1 year following hospital discharge and Schelling et al reported
26
no additional improvement in pulmonary function after the first year
following ARDS. Neff and colleagues reviewed 30 studies that evalu-
97
ated pulmonary function in ARDS survivors and found significant
98
variability in the proportion of patients with obstructive (0%-33%) and
restrictive (0%-50%) defects as well as compromised diffusion capacity
(33%-82%). Most recent data from 5-year outcomes after ARDS show
normal to near normal pulmonary function achieved by 6 months to FIGURE 15-5. Striae over the leg of an ARDS patient.
1-year after ICU discharge with continued stability over the 5-year
study period. Evaluation of detailed chest imaging in these patients also
showed minimal structural change to the pulmonary parenchyma in prolonged immobilization. There was a 5% prevalence of heterotopic
the majority of patients at 5 years after ICU discharge. One important ossification in the Toronto ARDS cohort study with all patients having
99
limitation in this dataset was that 40% of patients were followed in large joint immobilization, leading to important functional limitation
1
their homes and therefore volumetric and diffusion capacity data were (Fig. 15-4). Heterotopic ossification is remediable with appropriate
unavailable and some patients declined radiologic imaging at 5-year surgical intervention and screening for this may help to improve long-
follow-up. This spectrum of pulmonary dysfunction may relate to popu- term function.
lation heterogeneity with respect to evolving definitions or severity of
ARDS, severity of lung injury, ICU ventilatory strategy, prior history of ■ COSMESIS
lung disease or smoking, and the presence of other pulmonary processes The physically transformative nature of critical illness cannot be
that fulfill the ARDS definition but that have a very different natural his- overstated. Many patients suffer from the often devastating emotional
tory (eg, bronchiolitis obliterans organizing pneumonia). Most outcome effects related to their altered appearance. From 5-year outcomes
studies found ARDS survivors are often unable to resume their prior data in ARDS survivors, many patients had ongoing concerns about
2
physical function, but the degree of pulmonary dysfunction does not cosmesis including scars from laparotomy, chest tube, central line,
explain this degree of functional limitation. arterial line and tracheostomy insertion, burns, striae from volume
■ ENTRAPMENT NEUROPATHY AND JOINT CONTRACTURES overload, and facial scars from prolonged noninvasive mask ventilation

The Toronto ARDS Outcomes study observed a 6% prevalence of peroneal (Fig. 15-5). Many patients underwent tracheostomy revision. Patients
emphasized that cosmetic concerns contributed to social isolation and
and ulnar nerve palsies. Although this represents only a small proportion sexual dysfunction.
1
of patients, these nerve palsies complicated rehabilitation therapy and
precluded return to original work in some cases. Clavet and colleagues REHABILITATION FRAMEWORK—
highlighted the important contribution to disability made by the develop-
ment and persistence of contractures during an episode of critical illness. 100 INTERNATIONAL CLASSIFICATION OF 102
■ HETEROTOPIC OSSIFICATION The International Classification of Functioning, Disability, and Health
FUNCTIONING, DISABILITY, AND HEALTH
Heterotopic ossification is the deposition of paraarticular ectopic bone (ICF) construct emphasizes disability and morbidity as the central
and has been previously associated with polytrauma, burns, pancreati- determinants of health status. This is relevant if we consider that dis-
tis, and ARDS. Heterotopic ossification is linked with paralysis and ability after critical illness is etiologically neutral. The ICF differs
101

Section01.indd 109 1/22/2015 9:37:42 AM