R. Silbergleit et al., EFFECT OF PERMISSIVE HYPOTENSION IN CONTINUOUS UNCONTROLLED INTRAABDOMINAL HEMORRHAGE, Academic emergency medicine, 3(10), 1996, pp. 922-926
Objective: To determine the effects of aggressive fluid administration
vs permissive hypotension on survival, blood loss, and hemodynamics i
n a model of uncontrolled hemorrhage in which bleeding has been shown
to be continuous. Methods: In this porcine model, 10 animals were bled
through a flow-monitored shunt placed between the femoral artery and
the peritoneal cavity. The animals received either no fluid (n = 5) or
80 mL/kg lactated Ringer's solution (n = 5) during a resuscitation ph
ase between 10 and 20 minutes postinjury, followed by a 40-minute eval
uation phase. Arterial pressures, cardiac output (CO), and hemorrhage
rate were measured. Survival and blood loss were calculated outcome me
asures. Results: The difference in survival between the animals left h
ypotensive (40%) and those receiving normotensive resuscitation (20%)
was not significant (p = 0.49). In the animals receiving fluid resusci
tation, mean arterial pressure (MAP) and CO increased during the resus
citative phase, but all the animals suffered the same pattern of hemod
ynamic deterioration in the evaluation phase. Rate of hemorrhage durin
g the resuscitative phase was 20 +/- 5 mL/min in the animals not recei
ving fluid and 56 +/- 9 mL/min in the animals receiving fluids. Total
blood loss was subsequently 20 mL/kg greater in the animals receiving
fluids than in the animals without fluid resuscitation. Conclusions: I
n this model of continuous uncontrolled hemorrhage, the difference in
survival between the animals left hypotensive and the animals receivin
g fluid resuscitation was not statistically significant. Increases in
MAP and CO with fluid resuscitation were transient and were offset by
larger volumes of blood loss, In contrast to the aortotomy model (wher
e thrombosis is likely and hypotensive resuscitation has proven benefi
cial), this model suggests that in continuous bleeding, avoiding fluid
resuscitation has a much smaller effect on outcome. Much of the benef
it from hypotensive resuscitation may depend on having an injury that
can stop bleeding.