In addition, fluid resuscitation will dilute coagulation factors that help form and stabilize a clot, hence making it harder for the body to use its natural mechanisms to stop the bleeding.
Due to the lack of controlled clinical trials in this field, the growing evidence that hypotensive resuscitation results in improved long-term survival mainly stems from experimental studies in animals.
[9] The first published study in humans, in people with penetrating torso trauma, has demonstrated a significant reduction in mortality when fluid resuscitation was restricted in the prehospital period.
A more recent study (2011) performed by the Baylor Group on patients who required emergency surgery secondary to hemorrhagic shock was randomized to a mean arterial pressure (MAP) of 50mmHg versus 65mm Hg.
[11] Two large human trials of this technique have been conducted, which demonstrated the safety of this approach relative to the conventional target (greater than 100 mmHg), and suggested various benefits, including shorter duration of hemorrhage and reduced mortality.
[12][13] Johns Hopkins group performed a retrospective cohort review from National Trauma Data Bank that found a statistically significant difference in mortality for patients treated with pre-hospital intravenous fluids.
[14] Clinical data from well-controlled, prospective trials applying the concept of permissive hypotension in trauma patients are still missing.
Hypothermia is associated with many problems including a bleeding disorder, organ failure, and hypotension, and is one of the three components in the "Triad of Death" that is feared by all trauma specialists.
Its use may result in a dilution of clotting factors and erythrocytes, and therefore poorer control of bleeding and impaired oxygen transport to tissues causing further ischemic damage.
The results from the Traumatic Coma Data Bank show the influence of the presence or absence of hypotension (defined as one or more recordings of a systolic blood pressure ≤90 mm Hg) or hypoxia (PaO2 <60 mm Hg) at the time of admission) on the outcome of patients with traumatic brain injury and hypotension at admission to the hospital showed twice the mortality and a significant increase in morbidity when compared with patients who were normotensive.
[20] Evidence strongly suggests that the avoidance or minimization of hypotension during the acute and postinjury period following traumatic brain injury had the highest likelihood of improving outcomes of any one single therapeutic maneuver.