Shock Syndromes II

Recommendations: Isotonic crystalloids are indicated in hemorrhagic shock. In trauma, restricted

volume replacement, usually less than 1.5 L of a balanced crystalloid, should be used initially, and

hypotonic solutions (e.g., lactated Ringer with a sodium content of 131 mmol/L) should be avoided

in patients with head trauma to minimize fluid shifts into the cerebral tissue. The most recent

European guidelines on managing major bleeding and coagulopathy after trauma recommend

isotonic balanced crystalloids over saline.

Packed red blood cells (PRBCs) and blood products

Indicated when the estimated blood loss is greater than 30% of the total blood volume. Each PRBC

unit is expected to increase circulating Hgb by around 1 g/dL.

Amount of blood products to transfuse is based on clinical examination, given that the initial

hemoglobin or hematocrit reading may not reflect blood loss because of compensatory mechanisms.

Although there are no randomized controlled trials evaluating transfusion thresholds for trauma,

the European guidelines on managing major bleeding and coagulopathy after trauma recommend

maintaining a hemoglobin of 7–9 g/dL after initial resuscitation.

a liberal transfusion threshold (Hgb less than 9 g/dL) was associated with a higher 6-week survival

rate (95% vs. 91%, hazard ratio [HR] 0.55 [95% confidence interval [CI], 0.33–0.92; p=0.02]) and

lower rates of further bleeding (10% vs. 16%, p=0.01) and adverse effects (40% vs. 48%, p=0.02).

Notable limitations of the study include its single-center design and exclusion of patients with

cirrhosis who have cardiovascular disease.

ii.

Despite these limitations, a transfusion threshold of 7 g/dL was endorsed by the 2017 AASLD

Practice Guidance for Portal Hypertension Bleeding in Cirrhosis, with recommendations to

maintain hemoglobin at 7–9 g/dL.

A randomized controlled trial of patients undergoing cardiac surgery compared a restrictive

transfusion threshold (less than 7.5 g/dL) with a liberal transfusion threshold (less than 9 g/dL).

The groups did not differ with respect to the composite primary end point of serious infection

or ischemic event (35.1% vs. 33.0%; OR 1.11; 95% CI, 0.91–1.34; p=0.30).

ii.

However, more deaths occurred in the restrictive transfusion group (4.2% vs. 2.6%; HR 1.64;

95% CI, 1.00–2.67; p=0.045).

iii.

Therefore, a restrictive transfusion strategy after cardiac surgery cannot be recommended.

A study examined transfusion practices in hospitalized general medicine patients and tested for

differences in the Hgb concentration at which patients have transfusions and the total number of

RBC units received by patients’ race. The study aimed to determine any disparities in transfusion

practices according to race. In this study, African Americans had lower transfusion rates than

Whites (25% vs. 30%, respectively; p<0.01). For Hgb concentrations below a nadir Hgb of 9 g/dL,

African Americans had significantly lower transfusion rates than Whites. The transfusion rate for

Hgb concentrations of 8.0–8.9 g/dL was 1% for African American patients versus 7% for White

patient (p<0.01). The transfusion rate for Hgb concentrations of 7.0–7.9 g/dL was 15% and 28% for

African Americans and Whites, respectively (p<0.01). The transfusion rate for Hgb concentrations

below 7 g/dL was 80% for African Americans versus 86% for Whites (p<0.01). African American

patients also received fewer units of RBCs overall, with a beta coefficient of -0.17 (p<0.01), and

at lower Hgb concentrations, with a beta coefficient of 0.14 (p<0.01), than White patients. These

observed differences in the receipt of transfusion by race met the definition of a health care disparity.

Vasopressors

Attractive adjuncts in hemorrhagic shock to minimize the amount of fluid required to reverse tissue

hypoperfusion, but can increase cardiac afterload and are independently associated with increased

mortality in trauma