Noncolligative properties of intravenous fluids:

Analysis of hemodynamics and impedance using bioelectrical impedance analysis in hypovolemic shock-induced swine model

To treat hypovolemic shock, fluid infusion or blood transfusion is essential to address insufficient volume. Much controversy surrounds resuscitation in hypovolemic shock. We aimed to identify the ideal fluid combination for treating hypovolemic shock-induced swine model, analyzing bioelectrical impedance and hemodynamics. Fifteen female three-way crossbred pigs were divided into three different groups. The three resuscitation fluids were (1) balanced crystalloid, (2) balanced crystalloid + 5% dextrose water, and (3) balanced crystalloid + 20% albumin. The experiment was divided into three phases and conducted sequentially: (1) controlled hemorrhage (1 L bleeding, 60 min), (2) resuscitation phase 1 (1 L fluid infusion, 60 min), and (3) resuscitation phase 2 (1 L fluid infusion, 60 min). Bioelectrical impedance analysis was implemented with a segmental multifrequency bioelectrical impedance analyzer. A total of 61 impedance measurements were assessed for each pig at six different frequencies in five segments of the pig. Pulse rate (PR), mean arterial pressure (MAP), stroke volume (SV), and stroke volume variation (SVV) were measured using a minimally invasive hemodynamic monitoring device. The three-dimensional graph showed a curved pattern when infused with 1 L of balanced crystalloid + 1 L of 5% dextrose water and 1.6 L of balanced crystalloid + 400 ml of 20% albumin. The 1M impedance increased in all groups during the controlled hemorrhage, and continuously decreased from fluid infusion to the end of the experiment. Only balanced crystalloid + 20% albumin significantly restored MAP and SV to the same level as the start of the experiment after the end of fluid infusion. There were no significant differences in MAP and SV from the time of recovery to the initial value of 1M impedance to the end of fluid infusion in all groups. The change and the recovery of hemodynamic indices such as MAP and SV coincide with the change and the recovery of 1M impedance. Using balanced crystalloid mixed with 20% albumin in hypovolemic shock-induced swine model may be helpful in securing hemodynamic stability, compared with balanced crystalloid single administration.

Early autologous fresh whole blood transfusion leads to less allogeneic transfusions and is safe

BACKGROUND

The practice of transfusing ones' own shed whole blood has obvious benefits such as reducing the need for allogeneic transfusions and decreasing the need for other fluids that are typically used for resuscitation in trauma. It is not widely adopted in the trauma setting because of the concern of worsening coagulopathy and the inflammatory process. The aim of this study was to assess outcomes in trauma patients receiving whole blood autotransfusion (AT) from hemothorax.

METHODS

This is a multi-institutional retrospective study of all trauma patients who received autologous whole blood transfusion from hemothorax from two Level I trauma centers. Patients who received AT were matched to patients who did not receive AT (No-AT) using propensity score matching in a 1:1 ratio for admission age, sex, mechanism, type of injury, Injury Severity Score (ISS), Glasgow Coma Scale (GCS) score, systolic blood pressure, heart rate, hemoglobin, international normalized ratio (INR), prothrombin time, partial prothrombin time, and lactate. AT was defined as transfusion of autologous blood from patient's hemothorax, which was collected from the chest tubes and anticoagulated with citrate phosphorous dextrose. Outcome measures were in-hospital complications, 24-hour INR, and mortality. In-hospital complications were defined as adult respiratory distress syndrome, sepsis, disseminated intravascular coagulation, renal insufficiency, and transfusion-related acute lung injury.

RESULTS

A total of 272 patients (AT, 136; No-AT, 136) were included. There was no difference in admission age (p = 0.6), ISS (p = 0.56), head Abbreviated Injury Scale (AIS) score (p = 0.42), systolic blood pressure (p = 0.88), and INR (p = 0.62) between the two groups. There was no significant difference in in-hospital complications (p = 0.61), mortality (p = 0.51), and 24-hour postadmission INR (0.31) between the AT and No-AT groups. Patients who received AT had significantly lower packed red blood cell (p = 0.01) and platelet requirements (p = 0.01). Cost of transfusions (p = 0.01) was significantly lower in the AT group compared with the No-AT group.

CONCLUSION

The autologous transfusion of the patient's shed blood collected through chest tubes for hemothorax was found to be safe without complications in this study. It also reduced the need for allogeneic transfusions and decreased hospital costs. This study demonstrates safety data that would help in designing larger prospective multicenter studies to determine whether this practice is truly safe and effective.

LEVEL OF EVIDENCE

Epidemiologic/prognostic study, level III.

Traumatic coagulopathy--part 2: Resuscitative strategies

OBJECTIVE

To discuss the current resuscitative strategies for trauma-induced hemorrhagic shock and acute traumatic coagulopathy (ATC).

ETIOLOGY

Hemorrhagic shock can be acutely fatal if not immediately and appropriately treated. The primary tenets of hemorrhagic shock resuscitation are to arrest hemorrhage and restore the effective circulating volume. Large volumes of isotonic crystalloids have been the resuscitative strategy of choice; however, data from experimental animal models and retrospective human analyses now recognize that large-volume fluid resuscitation in uncontrolled hemorrhage may be deleterious. The optimal resuscitative strategy has yet to be defined. In human trauma, implementing damage control resuscitation with damage control surgery for controlling ongoing hemorrhage, acidosis, and hypothermia; managing ATC; and restoring effective circulating volume is emerging as a more optimal resuscitative strategy. With hyperfibrinolysis playing an integral role in the manifestation of ATC, the use of antifibrinolytics (eg, tranexamic acid and aminocaproic acid) may also serve a beneficial role in the early posttraumatic period. Considering the sparse information regarding these resuscitative techniques in veterinary medicine, veterinarians are left with extrapolating information from human trials and experimental animal models.

DIAGNOSIS

Viscoelastic tests integrated with predictive scoring systems may prove to be the most reliable methods for early detection of ATC as well as for guiding transfusion requirements.

SUMMARY

Hemorrhage accounts for up to 40% of human trauma-related deaths and remains the leading cause of preventable death in human trauma. The exact proportion of trauma-related deaths due to exsanguinations in veterinary patients remains uncertain. Survivability depends upon achieving rapid definitive hemostasis, early attenuation of posttraumatic coagulopathy, and timely restoration of effective circulating volume. Early institution of damage control resuscitation in severely injured patients with uncontrolled hemorrhage has the ability to curtail posttraumatic coagulopathy and the exacerbation of metabolic acidosis and hypothermia and improve survival until definitive hemostasis is achieved.

The Bellamy challenge: it's about time

In 1984, Col. Ronald Bellamy launched a worldwide challenge to develop a new resuscitation fluid to aid survival after catastrophic blood loss on the battlefield. In 1996, after careful compromise among need, cube weight and efficacy, the US military and later coalition forces adopted 6% hetastarch (HES) fluids for early resuscitation. In the intervening years, evidence has amassed indicating that the HES fluids may not be safe, and in June 2013 the US Food and Drug Administration issued a warning that HES solutions should not be used to treat patients with hypovolaemia or the critically ill. We review the unique challenges of early battlefield resuscitation, why the 'Bellamy challenge' remains open and discuss a number of forward-looking strategies that may help to solve the problem. The first two pillars of resuscitation that we believe have not been adequately addressed are rescuing and stabilising the heart (and brain) and the vascular system. The 'ideal' resuscitation fluid needs to nurture the heart and body slowly back to health, and not 'shock' it a second time with unnatural colloids or large volumes of unphysiological saline-based solutions.