Page 578 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

398 PART 4: Pulmonary Disorders

site after decannulation. Patients with prolonged intubations likely do The study detected no difference between groups for mortality, VAP
17
benefit from removing the endotracheal tube to reduce oropharyngeal rate, duration of mechanical ventilation or amount of sedative medica-
and laryngeal damage, but whether this offsets the potential tracheal tions required, but was likely underpowered to detect clinically impor-
complications of tracheostomy is unclear. We suggest that patients tant differences. Interestingly, only one quarter (16 of 62) patients that
18
23
with evidence of oral or pharyngeal ulceration and who are expected were randomized to receive prolonged intubation subsequently received
to require prolonged mechanical ventilation should be considered for a tracheostomy after 14 days. The authors did attempt to quantify the
conversion to tracheostomy. comfort of early tracheostomy, noting greater comfort in patients receiv-
There is some evidence from small trials that tracheostomy may ing early tracheostomy in the two-thirds of surviving patients that could
19
reduce the incidence of ventilator-associated pneumonia (VAP) in ICU complete follow-up.
patients requiring prolonged mechanical ventilation, but these patients The recent Italian trial of tracheostomy timing has already been dis-
20
were not systematically screened for the development of VAP. The cussed. No significant differences in mortality or VAP were observed
21
posited mechanisms through which this advantage might be realized comparing the early versus late tracheostomy groups. The duration of
include better oral care, more effective suctioning, and improved glottic mechanical ventilation and, hence, ICU stay were shortened, but there
compliance, resulting in less pooled secretions in the trachea. Recently, were no changes in hospital length of stay or other long-term outcome
a well-designed large trial from Italy evaluated the impact of tracheo- measures. Notably, more patients were subjected to the risk of tracheo-
stomy timing on the incidence of VAP among patients from 12 Italian stomy by an early tracheostomy strategy, with little quantifiable benefit. 22
ICUs with ongoing severe respiratory failure 24 hours after intubation. A recent United Kingdom multicenter randomized trial was con-
21
Of 600 patients studied, 419 did not significantly improve or worsen cluded in 2009 but has not yet been published. This trial (TRACMAN) is
according to standardized criteria evaluated 48 hours after enrollment. the largest conducted to date and enrolled 909 general ICU patients that
These patients were randomized to receive percutaneous tracheostomy were predicted to require greater than 7 days of mechanical ventilation.
24
after 6 to 8 days (early group) or after 13 to 15 days (late group) of laryn- Patients were randomized to receive early tracheostomy (within 4 days)
geal intubation. Monitoring for VAP was standardized and assessed by or late tracheostomy (after >10 days). The majority (93%) of patients in
blinded adjudicators in an effort to minimize ascertainment bias. There the early tracheostomy group received a tracheostomy compared with
was a statistically nonsignificant trend toward a reduction in VAP with less than half (45%) of the late group. There were no significant differ-
early tracheostomy. However, even if this trend were real (and the trial ences in 30 day mortality, ICU or hospital length of stay or antimicrobial
was underpowered to confirm it), the clinical benefit would appear use (although rates of VAP were not measured). There was decreased
small; earlier tracheostomy was not associated with reductions in mor- use of sedative medications in patients in the early tracheostomy group.
tality (at 28 days or 1 year) or hospital length of stay. This decreased use of sedation, although statistically significant, is of
questionable clinical significance considering that ICU length of stay
TIMING OF TRACHEOSTOMY was unaltered in the early tracheostomy group.
A unifying theme of these recent trials of earlier tracheostomy is that
The optimal timing of tracheostomy for patients that are antici- accurately predicting which patients will actually require prolonged
pated to have ongoing ventilator dependence remains controversial. mechanical ventilation is difficult and susceptible to cognitive biases
After a prolonged period of mechanical ventilation, the benefits of and uncertainty, even in the most rigorously conducted trials. A strategy
tracheostomy—in particular increased comfort and ease of connect- of performing early tracheostomy will inevitably involve performing
ing and disconnecting from the ventilator—will presumably start to more tracheostomies than are necessary, since many of the patients
outweigh the risks of the procedure. Numerous studies have attempted receiving the procedure would be liberated from mechanical ventilation
to elucidate whether performing tracheostomy earlier in a patient’s ICU without the procedure simply by waiting longer. Interestingly, the trials
stay confers other benefits, particularly considering time to successful have been inconsistent in detecting differences in sedative requirements
liberation from mechanical ventilation and mortality. Unfortunately, comparing early and late tracheostomy strategies, suggesting that seda-
study of the subject has been difficult for a number of reasons. tion use in modern ICUs may be minimized even among endotracheally
Retrospective studies are confounded by indication bias and survivor intubated patients by providing sedation vacations and protocolized
treatment bias. Randomized trials have also been problematic, mainly care. Similarly, other putative benefits of early tracheostomy may be
25
because accurate prediction of which patients will require prolonged minimized in the future as general ICU care improves, including adop-
ventilation has proven to be extremely difficult. The enrollment of tion of standardized weaning protocols and VAP prevention bundles.
22
patients into studies has also been limited by physicians’ fixed percep- The available studies examining the optimal timing of tracheostomy
tions of the benefits of tracheostomy. 13,23 have typically included a broad sampling of ICU patients predicted
A number of important studies of “early” versus “late” tracheo- to require prolonged mechanical ventilation, with a preponderance of
stomy have been published in the last decade. In 2005, a meta-analysis primary respiratory failure patients. It still remains to be elucidated
summarized five randomized and quasi-randomized trials published whether subpopulations exist, which may derive more benefit from early
between 1990 and 2004 and involving a total of 406 patients with diverse tracheostomy. A recent trial found no benefit to earlier tracheostomy for
conditions including trauma, head injury, medical, surgical and burn cardiac surgery patients that were expected to require prolonged mechan-
patients. A significant degree of heterogeneity also existed across these ical ventilation. Neurosurgical patients may have a prolonged need for
20
26
studies for definitions of “early” versus “late” tracheostomy. Overall, no airway protection, but require little in the way of ventilator support, and
difference was observed in mortality or rate of VAP. However, a signifi- these patients might therefore be liberated from mechanical ventilation
cant decrease in duration of mechanical ventilation and ICU length of immediately after tracheostomy. One trial did demonstrate earlier lib-
stay was observed for early tracheostomy (defined as <7 days). This eration from mechanical ventilation in head injured patients with early
meta-analysis was limited by the relatively small number of patients and tracheostomy, but detected no differences in rates of VAP or mortality.
27
small number of trials included. Studying the timing of tracheostomy in these patient subgroups poses
Since publication of this meta-analysis, several large trials have been other challenges, for example, correctly predicting which patients will
attempted. A trial conducted in France sought to randomize 468 patients be unable to protect their airway after extubation. Furthermore, per-
28
but was terminated because of low enrollment after randomizing forming early tracheostomy on patients with severe brain injury will be
123 patients from 25 ICUs. Patients that were predicted by their phy- undesirable for patients that are expected to die of their brain injury,
13
sicians to require prolonged mechanical ventilation (>7 days) were ran- and discussions of the risks and benefits of tracheostomy may only serve
domized to receive early tracheostomy (within 4 days) versus prolonged to complicate discussions of withdrawal of life-sustaining treatment in
translaryngeal intubation (with tracheostomy permitted after 14 days). patients with a predicted poor functional recovery.
13

section04.indd 398 1/23/2015 2:18:56 PM