Burns and Intra-abdominal hypertension
The severely injured burn patient represents a near ideal
combination of pathophysiologic events to cause intraabdominal
hypertension – massive systemic inflammatory response plus high
intravenous fluid requirements.
Because of the massive inflammatory response that occurs in
burn patients a major capillary leak develops. This is clearly
manifested by the fluid requirements of these patients and by the
external edema that is visible in all major burns. While the
external edema is readily apparent, capillary leak and edema in the
bowel wall as well as sequestration of cytokine rich free fluid
within the peritoneal cavity is substantial.[1] The end result is a
very high incidence of intra-abdominal hypertension in major burn
cases with prospective studies demonstrating abdominal compartment
syndrome in a majority of major burns.[2, 3]
Monitoring IAH and preventing over resuscitation of burn
patients
"Fluid Creep" is a term coined by Dr. Jeff Saffle
from the University of Utah. It implies over resuscitation of burn
victims with excess fluids. The reason it is so important is the
recognition that excess fluid administration in burns leads to
a very high incidence of IAH/ACS with worse outcomes. Being
conscious of this problem, aggressively intervening for IAH prior to
ACS and modifying the Parkland formula for fluid administration has
led to a dramatic reduction in ACS and its attendant morbidity and
mortality in his institution over the last decade. Others have
followed suit. Ennis et al began to more carefully assess fluid
status using CVP and IAP as markers
for over-resuscitation in Soldiers burned in the Iraq war. By
ceasing further fluid administration regardless of UOP once both IAP
and CVP were elevated the coalition medical forces have seen a
dramatic decrease in the incidence of abdominal compartment syndrome
as well as in mortality.[15]
Treatment
and prevention of IAH in the burn patient.
All major burn
patients should be aggressively monitored for the development of IAH
(ideally long before ACS occurs).[4-6] When treating a burn patient
with intraabdominal hypertension it is probably best to follow the
current guidelines put out by the World Society of abdominal
compartment syndrome
(click here for a link
to these protocols).
Escharotomy and
Paracentesis
Burn patients
with IAH may respond to unique treatment modalities – escharotomy
and paracentesis. If
they have torso burns, the initial treatment for rising IAP may be
escharotomy, allowing the abdominal cavity to expand and reducing
the abdominal pressure.[7, 8] Percutaneous drainage of fluid out of
the peritoneal cavity is another effective and less invasive
intervention for burn patients. Since these patients have such and
aggressive capillary leak they tend to leak fluid into the abdominal
cavity that can be removed using paracentesis.
Multiple authors describe successful reduction of
intra-abdominal pressure in burn patients treated with paracentesis.
Usually these drains are left in place for several days to acts as
continuous fluid and cytokine drains.[9-11] This intervention offers
two benefits – it provides an immediate reduction in IAP through
drainage for free fluid and a continuous outlet as excess abdominal
fluid accumulates, plus it removes high levels of pro-inflammatory
cytokines that accumulate in the gut – a process that likely reduces
serum inflammatory mediators and benefits the entire body.[1, 12]
Fluid selection
and volume:
Colloids or hypertonic resuscitation fluids may prevent
the progression of ACS in burn patients, though outcomes
improvements are conflicting.
Lawrence found albumin administration limited the amount of
fluid required in severely burned patients and assisted in
preventing full blown abdominal compartment syndrome.[13] O’Mara
found plasma resuscitation significantly reduced fluid use and
progression to ACS in their burn population.[14] Oda also noted
reduction in fluid requirements and the percentage of patients
developing ACS when hypertonic saline was introduced in his burn
protocol.[3] However, Bechir noted a worse outcome in major burn
patients – higher mortality and more renal failure - when hyperoncotic hydroxyethyl starch (HES) 200/0.5 (10%) was
used in an attempt to reduce complications including abdominal
compartment syndrome. A review by Latenser states that the only
consensus is that adequate fluid must be given to prevent early
death from major burns, that too much fluid must not be given to
reduce the risk of IAH/ACS and that there is no clinical advantage
demonstrated for colloids in meta-analysis of the data.[4] She
recommends the University of Utah treatment algorithm as a good
consensus document that implements early aggressive fluids with
initial urine output as an easy gage as to appropriate
resuscitation.
Fluid
resuscitation algorithm – University of Utah / Jeff Saffle MD
Using this algorithm as a guide, she recommends that all
patients with burns in excess of 30% TBSA and all patients with UOP
less than 15 ml/hr for 2 hours must have intra- abdominal pressure
monitoring implemented since high IAP will prevent renal perfusion,
making UOP monitoring much less reliable as a sign of under
resuscitation (click here to understand the
physiologic impact of IAP on renal function). Implementation
of this concept –ceasing further fluid administration regardless of
UOP once both IAP and CVP were elevated – has been used to treat
soldiers in the Iraq war and has led to a dramatic decrease in the
incidence of abdominal compartment syndrome as well as in
mortality.[15]
Summary:
IAH is
extremely common in burn patients and burn surgery experts recommend
all patients with large burns (20-30) and those with poor urine
output have their IAP monitored to ensure IAH/ACS is not
developing.[4, 5] Since large burns patients who develop ACS have
mortalities in excess of 80%, all patients with IAH should be
aggressively treated with a multimodal approach to reducing their
IAP and if unsuccessful early and aggressive decompressive
laparotomy should be implemented.[4, 16]
1.
Kowal-Vern, A., et al.,
Elevated cytokine levels in peritoneal fluid from burned patients
with intra-abdominal hypertension and abdominal compartment
syndrome. Burns, 2006.
2. Ivy, M.E., et al.,
Intra-abdominal hypertension and abdominal compartment syndrome in
burn patients. J Trauma, 2000.
49(3): p. 387-91.
3. Oda, J., et al.,
Hypertonic lactated saline resuscitation reduces the risk of
abdominal compartment syndrome in severely burned patients. J
Trauma, 2006. 60(1): p.
64-71.
4. Latenser, B.A.,
Critical care of the burn patient: the first 48 hours. Crit Care
Med, 2009. 37(10): p. 2819-26.
5. Azzopardi, E.A., et al.,
Fluid resuscitation in adults
with severe burns at risk of secondary abdominal compartment
syndrome-An evidence based systematic review. Burns, 2009.
6. Tuggle, D., et al., The
abdominal compartment syndrome in patients with burn injury.
Acta Clin Belg Suppl, 2007(1): p. 136-40.
7.
Tsoutsos, D., et al.,
Early Escharotomy as a Measure to Reduce Intraabdominal Hypertension
in Full-Thickness Burns of the Thoracic and Abdominal Area.
World J Surg, 2003.
8.
Oda, J., et al.,
Effects of escharotomy as abdominal decompression on cardiopulmonary
function and visceral perfusion in abdominal compartment syndrome
with burn patients. J Trauma, 2005.
59(2): p. 369-74.
9. Latenser, B.A., et al.,
A pilot study comparing percutaneous decompression with
decompressive laparotomy for acute abdominal compartment syndrome in
thermal injury. J Burn Care Rehabil, 2002.
23(3): p. 190-5.
10. Corcos, A.C. and H.F. Sherman,
Percutaneous treatment of
secondary abdominal compartment syndrome. J Trauma, 2001.
51(6): p. 1062-4.
11.
Parra, M.W., et al.,
Paracentesis for resuscitation-induced abdominal compartment
syndrome: an alternative to decompressive laparotomy in the burn
patient. J Trauma, 2006.
60(5): p. 1119-21.
12.
Kubiak, B.D., et al.,
Peritoneal negative pressure therapy reduces both peritoneal and
systemic inflammation and prevents abdominal compartment syndrome.
Acta Clinica Belgica, 2009.
64(3): p. 260 (Abstract 43).
13. Lawrence, A., et al.,
Colloid administration normalizes resuscitation ratio and
ameliorates "fluid creep". J Burn Care Res, 2010.
31(1): p. 40-7.
14. O'Mara, M.S., et al., A
prospective, randomized evaluation of intra-abdominal pressures with
crystalloid and colloid resuscitation in burn patients. J
Trauma, 2005. 58(5): p. 1011-8.
15.
Ennis, J.L., et al., Joint Theater Trauma System
implementation of burn resuscitation guidelines improves outcomes in
severely burned military casualties. J Trauma, 2008. 64(2 Suppl): p.
S146-51; discussion S151-2.
16. Hershberger, R.C., et al., Abdominal compartment syndrome in the severely burned patient. J Burn Care Res, 2007. 28(5): p. 708-14.