Hypotensive Resuscitation of Multiple Hemorrhages Using Crystalloid and Colloids

Abstract

Hypotensive resuscitation has been advocated as a better means to perform field resuscitation of penetrating trauma. Our hypothesis is that hypotensive resuscitation using either crystalloid or colloid provides equivalent or improved metabolic function while reducing the overall fluid requirement for resuscitation of hemorrhage. We compared hypotensive and normotensive resuscitation of hemorrhage using lactated Ringer's (LR) with hypotensive resuscitation using Hextend (Hex), 6% hetastarch in isotonic buffered saline. Instrumented conscious sheep were hemorrhaged in three separate bleeds, 25 mL/kg at T0 and 5 mL/kg at both T50 and T70. Resuscitation was started at T30 and continued until T180. Hypotensive resuscitation to a mean arterial pressure (MAP) of 65 mmHg was performed with LR or Hex using a closed-loop resuscitation (CLR) system for a LR-65 and Hex-65 treatment protocol. A control treatment protocol was resuscitation with LR to a MAP target of 90 mmHg, LR-90. All treatment protocols were successfully resuscitated to near target levels. Two animals in the hypotensive treatment protocols died during the second and third bleedings, one in the LR-65 and one in the Hex-65 treatment protocol. Mean infused volumes were 61.4 +/- 11.3, 18.0 +/- 5.9, and 11.6 +/- 1.9 mL/kg in the LR-90, LR-65, and Hex-65 treatments, respectively (*P < 0.05 versus LR-90). Mean minimum base excess (BE) values were +1.9 +/- 1.4, -5.8 +/- 4.3, and -5.9 +/- 4.0 mEq/L in the LR-90, LR-65, and Hex-65 treatments, respectively. Hypotensive resuscitation with LR greatly reduced volume requirements as compared with normotensive resuscitation, and Hex achieved additional volume sparing. However, trends toward lower BE values and the occurrence of deaths only in the hypotensive treatment protocols suggest that resuscitation to a target MAP of 65 mmHg may be too low for optimal outcomes.

Permissive Hypotension in Bleeding Trauma Patients: Helpful or Not and When?

“…The mortality rate (7.3%) was the same for both groups of patients. However, comparison of Injury Severity Scores 26 indicated that patients in the low group (scores, [16][17][18][19][20][21][22][23][24] were more severely injured (P = .02) than were patients in the conventional group (scores, 9-15). Thus, permissive hypotensive resuscitation may benefit restoration of blood circulation and cause a modest increase in blood pressure (reducing the risk of additional blood loss due to continued bleeding or rebleeding) with minimal fluid requirements.…”

“…20 A systematic meta-analysis of preclinical data (52 animal trials) 21 indicated an increased adjusted relative risk of death, from 0.69 to 1.80, when aggressive resuscitation was used in animals with less severe hemorrhage (ie, tail resection). In other trials, 16,17 attempts to increase MAP to 80 mm Hg with fluid resuscitation in animals with established hypovolemic shock were associated with decreased oxygen supply to the tissues, metabolic acidosis, and a poor outcome.…”

Blast injury research models

“…Consequently, the models used, while providing valuable information for a debate regarding civilian resuscitation, were less relevant to a potential military situation since the injury models are considered unsurvivable in a battlefield setting and military evacuation timelines can be considerably longer. With longer resuscitation timelines, tissue hypoperfusion, a serious limitation of the hypotensive strategy, assumes greater clinical significance ultimately leading to ischaemic damage [30,31]. The clinical evidence supporting hypotensive resuscitation is limited to short evacuation times to surgical care, e.g.…”

Does Somatostatin Decrease Hemorrhage From Injured Liver in Rats?

“…For the past 4 decades, the standard approach to the hypotensive trauma victims suffering from hemorrhagic shock to maintain adequate tissue perfusion and oxygenation is massive infusion of crystalloid solutions such as Ringer's lactate because blood products are not readily available in the pre-hospital settings (Stadlbauer et al, 2003, Stern 2001 Animal studies have shown that try to enhance normal blood pressure by early aggressive fluid resuscitation during uncontrolled hemorrhage of liver or spleen causes increased mortality (Rafie et al, 2004;Solomonov et al, 2000). Suggested mechanisms for increased mortality include diluted coagulating factors, increased blood pressure and disruption of an effective clot followed by secondary hemorrhage (Kowalenko et al, 1992).…”

“…Conversely, Lee et al (2007) demonstrated that delayed resuscitation also may be detrimental in terms of cytokine production profile and histopathological changes. Hence, some authors suggest that "limited" or "hypotensive" resuscitation may be preferable in the trauma patients to avoid detrimental effects of early aggressive or delayed fluid infusion (Kowalenko et al, 1992;Lee et al, 2007;Rafie et al, 2004;Stern, 2001).…”