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UROGENITAL
TRAUMA
Topical
haemostatics in renal trauma--an evaluation of four different substances
in an experimental
setting
Björses K, Holst J
Vascular Center, Malmö University Hospital, Lund University, Sweden
J Trauma. 2009; 66: 602-11
- Background: Damage control is valuable in hemodynamically unstable trauma patients.
To improve the hemostasis of packing, topical hemostatic agents have
been suggested. The effects of such agents are unclear in trauma situations.
The purpose of this study was to investigate the hemostatic capacity,
and the stability of the hemostatic clot, of four substances with different
mode of action in an experimental traumatic bleeding model.
- Methods: A standardized heminefrectomy was performed in 180 heparinized
and normotensive Sprauge-Dawley rats. Four different substances
were studied (separately
and in combinations) in a randomized fashion: gelatin (sponge and matrix),
bovine thrombin, freeze-dried recombinant factor VIIa (rFVIIa), and microporous
polysaccharide hemospheres. Eight treatment groups (15 animals/group) were
considered, primary endpoint was hemostasis within 20 minutes of observation.
The effective treatment groups were evaluated in a second set in the same
experimental model, but with a prolonged observation time after
hemostasis (60 minutes)
to control the stability of the clot.
- Results: Those animals treated with gelatin in the comparative study,
with and without thrombin or rFVIIa, obtained hemostasis. Thrombin
and rFVIIa
alone did not have any hemostatic capacity. Only 20% to 25% of the animals
obtained
hemostasis with microporous polysaccharide hemospheres alone or in combination
with rFVIIa. In the prolonged observation study, gelatin alone and in combination
with thrombin or rFVIIa was studied. On average, 34% (20%-54%) of the animals
rebled with no significant difference between the treatment groups.
- Conclusions: Gelatin-containing products provided a fast hemostasis
in this experimental model. One third of the animals rebled,
regardless of
whether
thrombin or rFVIIa was added. Further studies are demanded to confirm these
results clinically.
- Editorial
Comment
The above two articles on gunshot wounds to the kidney and the
other on haemostatic agents are both very timely and raise many
controversies and unanswered questions.
Although the authors hold on to the dogma of a one-shot IVP before any
renal exploration, I have generally found little utility it its
use. In our hands,
the IVP is usually a “fuzzy-gram” and adds little to the decision
making. While Morey et al published some value in the IVP in helping to grade
the renal injury, as to high or low grade, we have not had such luck. In
our trauma center, if the patient is stable enough to undergo imaging, we
take the patient to the CT scanner and get an accurate read as to the grade
of renal and associated injuries. If the patient is so unstable that no imaging
can be done and needs to be rushed to the OR, this patient is typically a “damage
control” patient where fancy and time consuming renal reconstructions
are a disservice to the patient. It is our feeling that a damage control
patient with a kidney injury needs to be observed, temporized by packing
or the like, or undergo a quick nephrectomy. In such an unstable patient,
a one-shot IVP will not help you or allow you to change your intra-operative
decision making. Furthermore, an easy way to assess contralateral kidney
function is to place a vessel loop to occlude the ipsilateral injured kidney
ureter, give indigo, and look for blue in the Foley. Blue indicates at
least a partially functional contralateral kidney. The notion that we should
do
a one-shot IVP on all patients to prevent taking out a solitary kidney
that has a 0.1% incidence makes no sense to me. While we are in the tissue
preservation
business, and would like to preserve every kidney, kidney repair should
not be at the expense of compromising patient recovery and survival from
the
associated injuries. While the urology community has been slow to accept
the above statements, there is mounting evidence from the general surgical
and trauma literature that one shot IVPs and getting primary vascular control
are dogma, and have little value in the contemporary setting.
I also have problems with the dogma of primary, proximal vascular control
of the renal hilum before opening Gerota’s fascia. By definition a
GSW to the kidney has penetrated Gerota’s so it is an uncontained hematoma
and Gerota’s is open already. In general, if the kidney injury is significant,
Grade 3-5, the hematoma has already done the kidney mobilization and dissection – so
getting the kidney to the midline to place a vascular clamp on the hilum
typically can be done very quickly and easily. Primary, proximal control
has value for a zone 1 hematoma where there is a potential injury to the
great vessels. Here getting proximal and distal control has great value to
prevent exsanguination. However, if the injury is just to the renal parenchyma,
I really don’t understand the need for proximal control - especially
in every patient. Furthermore, while the SF General group reports that it
takes only 10 minutes to get proximal control, in my own experience it typically
takes more like 20 plus minutes, especially on the right. So, in the unstable
and potential damage control patient I feel we do the patient a disservice
is delaying kidney repair for 20 or more minutes. They also report that they
only clamp the renal artery 12% of the time – that suggests to me that
they are over grading the renal injuries. In our experience, true grade 4
and 5 renal injuries are usually aggressively bleeding from the kidney, and
clamping the hilum expedites and facilitates renal repair. As long as the
warm ischemia time is < 30 minutes, I see no reason not to clamp the
artery. Furthermore, the use of adjunctive hemostatic agents, such as Floseal
and
the use of Nu-knit make sense to me and can expedite vascular control.
Such agents should not substitute for renal parenchymal suturing, but be
an adjunct,
expect perhaps in the very unstable damage control patient where packing
the kidney and applying agents can preclude the need for a damage control
nephrectomy.
The last comment I have is why we should treat low grade GSW to the kidney
any differently then a blunt renal injury, if the kidney grade for grade
injury is the same. Clearly high grade GSW have a high degree of blast
injury and delayed necrosis and need to be more aggressively explored and
repaired.
However, for low velocity GSW and no clear intra-abdominal injury, I feel
in this day and age of excellent interventional radiology imaging and the
readily available use of selective angio-embolization in most trauma centers,
that conservative management of isolated penetrating injuries, even grade
3 and 4 are very under utilized. Arguably, the rate of pseudoaneurysms
and AV fistulas can approach 25% in conservatively managed high grade penetrating
injuries – but an unnecessary abdominal exploration can be avoided – in
so doing expediting morbidity and recovery time.
Dr.
Steven B. Brandes
Associate Professor, Division of Urologic Surgery
Washington University in St. Louis
St. Louis, Missouri, USA
E-mail: brandess@wudosis.wustl.edu
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