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Bozeman, Ross
In summary, ACS remains a major issue facing vascular
surgical and critical care teams regardless of the repair chosen. REVAR has been demonstrated to be a successful and
promising strategy to treat rAAA, but vigilance for the development of ACS and its subsequent management remains
an essential component contributing to favorable outcomes.
6. When to Decompress?
The gold standard for treatment of ACS is decompressive
laparotomy. However, escalating care to an open abdomen
state carries with it real concerns for the patient.
Strategies exist for management of IAH which has not
progressed to ACS. An IAP >12 mmHg should signal the
critical care team that physiologic derangements are evolving and progression to ACS is possible.
Neuromuscular blockade for ventilated patients is often
a useful treatment measure, especially early in the course
of the disease process. Relaxation of the abdominal and
thoracic musculature can allow increased intra-abdominal domain and reduce the intra-abdominal pressure.
Neuromuscular blockade should always be combined with
sedation and analgesia.
Other treatment strategies such as adequate pain control,
including the use of parenteral medications and/or thoracic
epidural anesthesia, conservative crystalloid use, correcting
positive fluid balance with careful use hypertonic colloid
solutions, diuresis and goal directed resuscitation, and the
use of vasopressors to support an abdominal perfusion
pressure ≥60 mmHg offer temporizing strategies for patients with IAH but not fully developed ACS [25, 26].
These conservative measures are no longer appropriate
once ACS has been identified. An IAP of >30 mmHg, especially, can signal impending cardiovascular collapse and
urgent decompression is mandatory [25].
A full midline laparotomy should be utilized once ACS is
recognized. The immediate decrease in IAP can exacerbate
hypotension in the periprocedural time period, and the
need for further resuscitation should be anticipated.
Percutaneous catheter decompression (PCD) is receiving
increasing attention as an alternative to decompressive
laparotomy in the treatment of patients with ACS [33].
Patients with rAAA treated by REVAR may have free intra-abdominal blood and fluid amenable to percutaneous
drainage.
However, active hemorrhage and coagulopathy may contraindicate PCD; hence, the use of this technique following
REVAR requires caution and further study. Continuous
monitoring of IAP and parameters of organ function is necessary if PCD is employed because PCD may not be successful in relieving ACS in all cases.
Cheatham and Safcsak [33] recently reported successful
avoidance of decompressive laparotomy in 25 of 31 patients
with ACS treated by PCD. A small cohort of these patients
CV DIRECTIONS VOL. 2, NO. 2
had had vascular procedures, but no further information
was provided.
This technique is particularly attractive as an alternative
to open abdominal management in patients who have
required aortic replacement, whether by standard or
endovascular techniques, but further clinical experience is
required to define its role in the vascular setting.
7. Prophylactic Delayed Abdominal Wound Closure
versus Decompressive Laparotomy
Prophylaxis against the development of IAH and ACS at the
end of the index procedure may be achieved by using open
abdomen management strategies, that is, delayed abdominal closure.
Intra-abdominal bladder pressure readings may be falsely
reassuring in a patient with an abdomen open at the end of
a procedure, and in such cases, clinical factors may be used
to decide whether or not to primarily close the fascia.
Patient presentation (degree of hypotension , acidosis,
hypothermia, resuscitation requirement), operative details
(length >4 hours, intra-operative resuscitation, blood loss,
etc.), the amount of bowel and abdominal wall edema,
abdominal tension, and its effect on peak airway pressures
at attempted closure suggest that IAH and ACS are likely to
occur in the postoperative period.
Rasmussen et al. [12] used delayed closure of the abdominal wall with a mesh bridge in such situations. Severe
base deficit (−14 versus −7), increased fluid resuscitation
(4.0 L/hr versus 2.7 L/hr), and hypothermia (32◦C versus
35◦C) were used as surrogates to predict the need for mesh
closure.
When compared to a subset of patients requiring decompressive laparotomy due to the development of ACS, those
patients closed with mesh at the initial operation had lower
MOF scores (P < 0.05), a lower mortality rate (51% versus
70%), and were more likely to survive their MOF (70%
versus 11%, P < 0.05).
This data supports the use of prophylactic delayed abdominal closure in those at risk for postoperative ACS.
The decision to perform a decompressive laparotomy with
conversion to an open abdomen or to prophylactically delay
abdominal wound closure is not taken lightly by vascular
surgical teams. Graft infection has long been a dreaded
complication of aortic replacement, and fears of increased
risk of graft infection with an open abdomen may cause
hesitation in definitive management of ACS by vascular
surgeons.
Multiple studies (Table 3), however, have shown aortic
graft infection in the setting of open abdominal management to be a very rare complication [7–20]. Ross et al. [17]
reported a series of 23 patients from both a community and
academic hospital setting where prophylactic delayed abdominal closure was employed based on clinical risk factors
13