An observational study of vasopressin infusion during uncontrolled haemorrhagic shock in a porcine trauma model: Effects on bowel function

Global longitudinal strain changes during hemorrhagic shock: An experimental study

OBJECTIVES

Global longitudinal strain (GLS) appears sensitive and reproducible to identify left ventricular systolic dysfunction. The main objective was to analyze the GLS changes in an anesthetized-piglet model of controlled hemorrhagic shock (HS). The secondary objective was to evaluate if GLS changes was different depending on the expansion fluid treatment with or without norepinephrine.

METHODS

Eighteen anesthetized and ventilated piglets were bled until the mean arterial pressure reached 40 mmHg. Controlled hemorrhage was maintained for 30 min before randomizing the piglets to three resuscitation groups: control group, LR group (resuscitated with lactated ringer), and NA group (resuscitated with lactated ringer and norepinephrine).

RESULTS

There was no difference in the baseline hemodynamic, biological, and ultrasound data among the three groups. During the hemorrhagic phase, the GLS increased significantly from 25 mL/kg of depletion. During the resuscitation phase, the GLS decreased significantly from 20 mL/kg of fluid administration. There was no difference in GLS variation among the groups during the hemorrhagic, maintenance, and resuscitation phases.

CONCLUSION

In our HS model, GLS increased with hemorrhage and decreased during resuscitation, showing its preload dependence.

Evaluation of capillary leakage after vasopressin resuscitation in a hemorrhagic shock model

Background

Hemorrhagic shock (HS) is a major threat to patients with trauma and spontaneous bleeding. The aim of the study was to investigate early effects of vasopressin on metabolic and hemodynamic parameters and endothelium permeability by measuring capillary leakage compared to those of other resuscitation strategies in a HS model.

Methods

Forty-five Sprague-Dawley rats were randomized into five groups: S group (n = 5), sham-operated rats without shock or resuscitation; HS group (n = 10), HS and no resuscitation; RL group (n = 10), HS and resuscitation with Ringer’s lactate (RL); RLB group (n = 10), HS and resuscitation with two-third shed blood plus RL; and vasopressin group (n = 10), HS and resuscitation with RL, followed by continuous infusion of 0.04 U/kg/min vasopressin. The effects of resuscitation on hemodynamic parameters [mean arterial pressure (MAP), superior mesenteric artery blood flow (MBF), and mesenteric vascular resistances (MVR)], arterial blood gases, bicarbonate, base deficit, and lactate levels as well as on capillary leakage in the lung, ileum, and kidney were investigated. Capillary leakage was evaluated with Evans blue dye extravasation.

Results

In the vasopressin group, the MAP was higher than in the RL and RLB groups (p < 0.001), while MBF was decreased (p < 0.001). MVR were increased only in the vasopressin group (p < 0.001). Capillary leakage was increased in the lungs of the animals in the vasopressin group compared to that in the lungs of animals in the RLB group (p < 0.05); this increase was associated with the lowest partial pressure of oxygen (p < 0.05). Conversely, decreased capillary leakage was observed with vasopressin in the ileum (p < 0.05). Increased capillary leakage was observed in the kidney in the RLB and vasopressin groups (p < 0.05). Lastly, vasopressin use was associated with higher base deficit and lactate levels when compared to the RL and RLB groups (p < 0.001).

Conclusion

Although vasopressin was proposed as a vasoactive drug for provisional hemodynamic optimization in the early phase of HS resuscitation, the overall findings of this experimental study focus on the possible critical side effects of vasopressin on metabolic parameters and endothelium permeability.

Acute coagulopathy in a porcine venous hemorrhage and ischemia reperfusion model

BACKGROUND

Injury-related coagulopathy is a complex process. We analyzed coagulation in a swine model of shock using rotational thromboelastometry (ROTEM).

METHODS

Forty-eight swine underwent laparotomy, 35% hemorrhage, supraceliac aortic cross-clamp, then reperfusion and resuscitation. ROTEM measurements and standard labs were taken at baseline and 6 hours into resuscitation.

RESULTS

Clot formation time (98 vs 53 seconds, P = .001) and international normalized ratio (1.67 vs 1.01, P < .001) were prolonged after resuscitation. Maximum clot firmness (61 vs 72 mm, P < .001) and fibrinogen levels (94 vs 165, P < .001) declined significantly during resuscitation. Despite decreased fibrinogen levels, there was no significant increase in fibrinolysis as measured by maximum lysis (3.9% vs 3.8%, P = .99).

CONCLUSIONS

ROTEM demonstrated the development of an acute coagulopathy. The most significant impacts on coagulopathy were seen with clot initiation and fibrin polymerization. Clot strength decreased over time, although there was little impact on clot breakdown because of fibrinolysis.

Arginine vasopressin: the future of pressure-support resuscitation in hemorrhagic shock

BACKGROUND

Arginine vasopressin (AVP) is a key player in maintaining the intravascular volume and pressure during hemorrhagic shock. During the past 2 decades, animal studies, case reports, and reviews have documented the minimized blood loss and improved perfusion pressures in those receiving pressure support with AVP.

MATERIALS AND METHODS

A PubMed search of studies was conducted with the terms: "AVP," "arginine vasopressin," "antidiuretic hormone," "hemorrhagic shock," "hemorrhage," "circulatory shock," "fluid resuscitation," "trauma," "massive transfusion protocol," "physiology," "cerebral," "renal," "cardiac," "perfusion," "dose," and "hypotension." The studies were located by a search of a combination of these terms. Also, within-PubMed citations relating to the studies gathered from the initial search were explored. Reports discussing vasopressin in hemorrhagic states were considered. No predetermined limit was used to choose or exclude articles.

RESULTS

AVP is an important hormone in osmoregulation and blood pressure. During stress, such as hemorrhage, the levels have been shown to rapidly decrease. Furthermore numerous animal studies and limited human studies have shown that circulatory support with AVP is linked to improved outcomes. No large human prospective studies are available to guide its use at present, but some of its effectiveness seems to lie in its ability to increase calcium sensitivity in acidotic environs, thereby allowing for more effective maintenance of vascular tone than catecholamines. It also redirects blood from the periphery, creating a steal syndrome, and increases the oxygen supply to vital organs, minimizing blood loss, and allowing additional time for surgical repair.

CONCLUSIONS

With these encouraging data, there is hope that "pressure support" will be the "resuscitation" considered necessary for a patient's optimum survival.

Vasopressin for hemorrhagic shock management: revisiting the potential value in civilian and combat casualty care

The evolution of trauma care is driven by a synergistic relationship between civilian and military medical systems. Although the characteristics of civilian injuries differ from those encountered on the battlefield, the pathophysiologic process of dying is the same and dominated by exsanguination and central nervous trauma. As such, therapies that interfere with the physiologic ability to compensate hemorrhage may play a key role to buy time until hemostatic surgery can be initiated. From a variety of remedies with the potential to prolong the compensation phase or to reverse the decompensation phase of shock, arginine vasopressin (AVP) is one of the most promising and best-evaluated drugs. Animal studies and various case report series provide some evidence that AVP may improve blood pressure even when conventional therapies fail, thus preventing hypovolemic cardiac arrest and enabling resuscitation from fatal hemorrhage. On the basis of this civilian experience, it seems reasonable to consider AVP for hypotensive resuscitation in the austere, resource-constrained battlefield environment. However, the significance of AVP as a rescue medication for life-threatening hemorrhage has yet to be proven.

A treatment protocol including vasopressin and hydroxyethyl starch solution is associated with increased rate of return of spontaneous circulation in blunt trauma patients with pulseless electrical activity

BACKGROUND

Survival after cardiopulmonary resuscitation (CPR) using standard vasopressor therapy is disappointing. Vasopressin is a potent vasopressor that could become a useful therapeutic alternative in the treatment of cardiac arrest.

AIMS

The aim of this prehospital prospective cohort study was to assess the influence of treatment with vasopressin and hydroxyethyl starch solution (HHS) on outcome in resuscitated blunt trauma patients with pulseless electrical activity (PEA) cardiac arrest.

METHODS

Two treatment groups of resuscitated trauma patients in cardiac arrest were compared: in the epinephrine group patients received epinephrine 1 mg IV every 3 min only; in the vasopressin group patients first received hypertonic HHS and arginine vasopressin 40 units IV only or followed by epinephrine 1 mg every 3 min until cessation of CPR. Medical trauma care was provided according to advanced trauma life support (ATLS) guidelines.

RESULTS

The study included 31 patients and there were no significant demographic or clinical differences between the treatment groups. Significantly more circulatory restorations [11/13 (85%) vs 3/18 (17%); P < 0.01] and better 24-h survival rates [8/13 (62%) vs 2/18 (11%); P = 0.001] were observed in the vasopressin group. Average mean arterial pressure (100.4 +/- 11.4 mmHg vs 80.3 +/- 12.4 mmHg) and final end-tidal partial pressure of carbon dioxide (PETCO(2)) at admission (4.5 +/- 0.9 kPa vs 2.8 +/- 0.4 kPa) were also higher in the vasopressin group.

CONCLUSION

Our results suggest that victims of severe blunt trauma with PEA should be initially treated with vasopressin in combination with HHS volume resuscitation followed by standard resuscitation therapy and other procedures when appropriate. Vasopressin might be potentially lifesaving in blunt trauma cardiac arrest compared to standard treatment with epinephrine.