Following injury the otherwise healthy individual has a natural ability to clot off bleeding. The higher the pressure in your vessels, the harder it is for the bleeding to stop, since the fluid essentially "pushes" the clot out and consequently the bleeding resumes. In more technical terms:<unk>  facilitates in vivo coagulation. This is especially true in patients who still have active bleeding. Attempts to normalize blood pressure in case of uncontrolled bleeding as in victims with penetrating trauma, may result in increased blood loss and worse outcomes. In this context, restriction of fluid resuscitation may actually improve outcome. This concept has been supported by animal studies that have demonstrated aggressive fluid resuscitation increase the volume of hemorrhaging fluid to a significant level as well as increasing mortality. Another issue with aggressive fluid resuscitation is the potential for hypothermia if fluids that are stored at room temperature are used. If these fluids are not warmed prior to infusion (which sometimes time does not permit for), this can result in a significant drop in core body temperature. Hypothermia is associated with many problems including bleeding disorder, organ failure, and<unk> , and is one of the three components in the "Triad of Death" that is feared by all trauma specialists. The crystalloid fluid used in initial resuscitative efforts does not contain any clotting factors or erythrocytes (red blood cells). 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. Additionally, crystalloids have an acidic pH, and the administration of large quantities of isotonic or slightly hypertonic crystalloid solutions such as 0.9% normal saline or Lactated Ringer's can cause or aggravate metabolic acidosis, another component of the "Triad of Death" leading to a decrease in myocardial (heart muscle) function. It is important to remember that<unk>  is a temporizing measure to improve outcomes until the source of bleeding is controlled. There are issues associated with prolonged<unk>  (> 90 min considered prolonged where detrimental effects outweigh benefits according to most recent animal studies - no human data available to date) that must be taken to account. Prolonged<unk>  can lead to aggravated post-injury coagulopathy (coagulation dysfunction), ischemic damage secondary to poor tissue perfusion including the brain, mitochondrial dysfunction, and lactic acidosis among others. It is also possible that other substances, such as estrogen (17 beta-estradiol) could allow for longer models of<unk> . In a rat model of hemorrhagic shock, estrogen was able to reduce some of the negative effects of prolonged<unk>  as well as prolong long-term survival.
Permissive hypotension
Reflex bradycardia
Vasodilatory shock
Pseudohypertension
Heat syncope
Parasympathetic rebound
Hypovolemic shock
Vasoplegic syndrome