7.1

Shock and Resuscitation

Chapter 7

Shock and Resuscitation

Introduction

The goal of fluid resuscitation is to maintain adequate perfusion.

Fluid resuscitation of the wounded combatant remains a

formidable challenge on the modern day battlefield. Routine

resuscitation using 2 L of crystalloid through two large bore

IVs is not appropriate in all situations and the vast majority of

the casualties do not need any IV resuscitation prior to arrival

at a forward medical treatment facility (MTF).

This chapter will briefly address shock, including recognition, classification, treatment, definition, and basic pathophysiology. Initial

as well as sustained fluid resuscitation and a review of currently

available fluids and potential future products will be described.

Recognition and Classification of Shock

Shock is a clinical condition marked by inadequate organ

perfusion and tissue oxygenation, manifested by poor skin

turgor, pallor, cool extremities, capillary refill greater than 2

seconds, anxiety/confusion/obtundation, tachycardia, weak or

thready pulse, and hypotension. Lab findings include base

deficit > 2, and lactic acidosis > 2.5 mmol/L.

 Hypovolemic shock: Diminished volume resulting in poor

perfusion as a result of hemorrhage, diarrhea, dehydration,

and burns (see Chapter 28, Burns). This is the most common

type of shock seen in combat soldiers (see Table 7-1).

Hypotension is a late finding in shock, after 30%–40%

lost blood volume. Earlier signs are tachycardia,

decreased pulse pressure, and mental status changes.

Tachycardia is often not reliable; however, and relative

bradycardia is common.
7.2

Emergency War Surgery

 Cardiogenic shock: Pump failure from intrinsic cardiac failure

or obstructive cardiac dysfunction from a tension pneumothorax, or cardiac tamponade with distended neck veins, or

unilateral absence of breath sounds.

 Distributive shock: Poor perfusion due to loss of vascular

tone; neurogenic shock: bradycardia with hypotension, seen

with spinal cord injury.

ο Treat hemorrhagic shock first.

ο Volume resuscitation to maintain systolic BP > 90 mm Hg.

ο Consider the addition of a vasopressor to address the loss

in vascular tone—phenylephrine (50–300 μg/min) or

dopamine (2–10 μg/kg/min).

 Septic shock: Fever, hypotension, and warm extremities from

massive vasodilation, usually seen 5–7 days after initial trauma.

Treatment of Traumatic Shock—Control Bleeding!

The goal in the treatment of shock is to restore tissue perfusion

and oxygen delivery (dependent on hemoglobin, cardiac output,

and oxygenation).

 Secure the airway and administer O2 for SaO2 < 92%.

 Diagnose and treat tension pneumothorax.

 Control obvious bleeding and assess for occult hemorrhage.

 Assess circulation and establish IV access.

Central

Blood Vol. Heart Respiratory Blood Nervous

Lost* Rate Rate Pressure System

Table 7-1. Clinical Correlates in Hypovolemic Shock.

*Blood volume is approximately 7%, so a 70 kg patient has a blood volume

of 4,900 mL.

≤ 15%

15%–30%

30%–40%

> 40%

Minimal

tachycardia

Tachycardia

Marked

tachycardia

Marked

tachycardia

No change

Tachypnea

Marked

tachypnea

Marked

tachypnea

No change

Decreased

pulse pressure

Systolic

hypotension

Severe

systolic

hypotension

No change

Anxiety or

combativeness

Depressed

mental status

Comatose
7.3

Shock and Resuscitation

ο Consider cardiac tamponade even if no distended neck veins.

 Administer IV fluids.

ο Hemorrhagic shock: Initially, any fluid available.

♦ LR: 1,000 mL expands intravascular volume by ~ 250 mL

within 1 hour after injection.

♦ 6% hetastarch: 500 mL expands intravascular volume

by ~ 800 mL in 1 hour, is functionally equivalent to 3

bags of LR, and is sustained for at least 8 hours.

♦ 7.5% hypertonic saline (HTS) results in the same physiologic response with 1

/8th the volume of LR or saline. Two

infusions of 250 cc can be used. Although this recommendation has been made by the Institute of Medicine

(Washington, DC) and two military consensus groups,

7.5% HTS is not commercially available. 3% and 5% HTS

can be used instead and are formulary stock items.

ο Nonhemorrhagic shock: Crystalloid is the fluid of choice.

♦ Within 1 hour, resuscitate to a mean arterial pressure of

> 60 mm Hg, a urine output of 0.5 cc/kg/h, and SaO2 of

> 92%.

 Based on response to fluids, casualties will fall into 3 groups:

ο Responders: Casualties with a sustained response to fluids

probably have had significant blood loss but have stopped

bleeding. However, they may still require definitive

surgery.

ο Transient and nonresponders are continuing to bleed.

They need immediate surgical intervention.

♦ Start blood transfusion as soon as possible.

♦ For nonresponders, fluids may be given to keep the

patient alive, but one should not attempt to restore

pressure to normal. Consideration should be taken into

account of the futility of the resuscitation depending

on the tactical scenario.

♦ Follow controlled resuscitation guidelines presented

below.

Exsanguinating hemorrhage is the cause of most

preventable deaths during war. Combat casualties in

shock should be assumed to have hemorrhagic shock

until proven otherwise.
7.4

Emergency War Surgery

 Vasopressors have no role in the initial treatment of

hemorrhagic shock.

 Fluid choices.

The ideal fluid for resuscitation is still debated despite decades

of research that began during WW I (see chart on next page).

Concept of Controlled (Hypotensive/Limited/Balanced)

Resuscitation

 Raising the blood pressure with fluid resuscitation may

dislodge established clots leading to more blood loss. Prior

to establishing definitive hemorrhage control, use controlled

resuscitation to achieve and maintain adequate perfusion as

demonstrated by at least one of the following prioritized

goals:

ο Regains consciousness (follows commands).

ο Palpable radial pulse.

ο SBP ~90 mm Hg.

ο MAP of ~60 mm Hg.

Controlled resuscitation is NOT a substitute for definitive

surgical control. It is an attempt to keep a very sick

patient alive until he can get to definitive treatment.

 Endpoints of resuscitation.

ο Following definitive hemorrhage control, more traditional

endpoints of resuscitation include

♦ Blood pressure: SBP > 120 mm Hg, MAP > 70 mm Hg.

♦ Urine output: > 0.5 mL/kg/h (approximately 30 mL/h).

♦ Correction of acidosis:

◊ base deficit < 2.

◊ serum lactate < 2.5 mmol/L.

♦ Hypothermia: It is important to maintain normal body

temperature. Fluids and patient care areas should be

warmed. This is often not possible in the deployed

environment. Patients frequently arrive at the facility

already hypothermic. Keep patients covered when on

litters, radiograph tables, and operating tables. External

warmers (such as contained forced warm air devices,

eg, Bair Hugger) should be employed in all patient care
7.5

Shock and Resuscitation

Fluid/Initial Dose Indication Advantages Cautions *Not FDA approved

Crystalloids

Saline

Ringer’s Lactate

Hypertonic saline (HTS)

3%–5%

7.5%*

Hypertonic salinecolloid combinations*

HTS dextran*

HTS hetastarch*

Colloids

Albumin

Artificial colloids

Dextran

6% hetastarch

(Hextend, Hespan)

10% Pentastarch*

Gelatin-based colloids*

Oral rehydration fluids

Blood

Artificial blood

Hemoglobin based

Fluorocarbon based

Hypovolemia, dehydration,

hemorrhage, shock, burns

Hemorrhagic shock:

4cc/kg or 250 cc bolus,

may repeat once

Burns—only one dose

initially

Hemorrhagic shock

250-500 mL bolus

Burns? Third day

Dehydration controlled

hemorrhage

Burns

Hemorrhage—Type O

universal donor

Hemorrhage

Easy to store

Inexpensive

Proven effectiveness

Isotonic

Lighter weight

Small volume = large effect

Increased cardiac contractility

Longer duration of effect than plain

HTS?

Longer duration

1:1 replacement for blood

Raises plasma oncotic pressure

Recruits extravascular fluid

Weight/cube better than crystalloids

Fluids of opportunity

Nonsterile ingredients:

4 tsp sugar, 1 tsp salt, 1 L water

Carries oxygen

Autotransfusion

Walking blood bank

Easy storage

No type and cross matching

Weight ratio – requires 3:1 for lost blood

Dilution, edema, coagulopathy

> 500cc – Risk of hypernatremia, seizures

Do not use for dehydration from vomiting,

diarrhea or sweating, or heat injuries

Do not repeat without addition of other fluids

Must replace depleted extravascular fluid

Overuse may lead to “leak” into tissue

Binds immunoglobulins and Ca++

Must replace depleted extravascular fluid

Artificial colloids:

Coagulopathy, allergic reaction, osmotic

diuresis, interferes with crossmatching

Hetastarch: ↑ fibrinolysis, ↑ Amylase

Max dose: 20 mL/kg/d (about 1.5 L)

Austere option in abdominal wounds and

unconscious patients, but use with caution

Storage, type and cross-match

Transfusion reactions, infection,

immunogenic

Experimental only, not yet available for use

Fluorocarbons require supplemental O2

Future option?
7.6

Emergency War Surgery

areas from initial emergency area through operating

room and ICU. Hypothermia is much easier to prevent

than it is to treat. See further discussion of hypothermia

in Chapter 12, Damage Control Surgery.

Transfusion Therapy

 Blood transfusion.

Blood should be added to the resuscitation of patients who have

lost 30%–40% of their blood volume. Blood may also be

necessary in patients who have not reached this threshold but

have ongoing blood loss. Whole blood has a greater risk for

immunologic reactions than packed cells.

Blood products fielded with forward medical units (FST, CSH) are

predominantly group O packed red cells and FFP. Upon reaching

a stabilization phase of operations, type-specific packed cells and

platelets will be supplied through theater specific channels. Storage,

shelf-life, and availability of these products are outlined in Table 7-2.

Table 7-2. Blood Products Available to the Theater.

Blood Group

Unit of Shelf Life for Echelon Availability

Product Issue Storage Transfusion Availability O+/- A+/- B+/- AB+/-

Liquid ~250mL 35d 35d Second & 100% — — —

PRBCs third (MASH)

Third (CSH) 50% 40% 10% —

& fourth

Frozen/ ~250mL 10y 3d (postwash) Third & fourth 100% — — —

deglycerolized

RBCs

FFP ~250mL 1y 24h (postthaw) Third & fourth — 50% 25% 25%

Platelet ~60mL 5d 5d Third & fourth 50% 50% —* —*

concentrate

* Will be provided by blood bank platoon and medical treatment facilities by in-theater blood collections.

CHS: combat support hospital; FFP: fresh frozen plasma; MASH: mobile army surgical hospital;

PRBCs: packed red blood cells; RBCs: red blood cells

Adapted from US Department of the Army. Planning for Health Service Support. Washington,

DC: Headquarters, DA; approved final draft January 1994. Field Manual 8-55: 8-6.
7.7

Shock and Resuscitation

Familiarity with transfusion technique, patient-donor unit

infusion connections, and walking blood bank connections, is

essential and should be practiced routinely. Most serious

transfusion reactions are the result of an error at the bedside,

not an error in typing and cross-matching (ie, transfusing “the

right unit to the wrong patient”).

 Transfusion reactions may be difficult to recognize in

severely or multiply injured casualties. Hemolytic (ABO

mismatch) reactions present acutely (< 24 hours) with fever,

chills, back pain, dyspnea, and renal failure. Delayed reactions

may occur. Transfusion should be halted immediately in all

cases, except minor allergic reactions (urticaria, fever, +/-

mild bronchospasm), which are treated with diphenhydramine (25–50 mg IV or PO), H-2 blocker, methylprednisolone, +/- epinephrine.

Field Management of a Transfusion Reaction

• Stop the infusion of blood. Continue to infuse normal

saline through the intravenous line.

• Examine the urine for hemoglobinuria. Examine plasma

for hemoglobinemia.

• Maintain blood pressure and urinary output with saline.

Consider administering mannitol or furosemide after

volume repletion if the patient is oliguric.

• Reexamine the donor unit for seal integrity, evidence

of hemolysis or infection, and recheck the transfusion

log for clerical error.

• Annotate the field medical card with a description of

the suspected reaction and the therapy provided.

Transfer the unit suspected of causing the reaction to

the next echelon of care with the casualty.

 Clinical relevance of the Rh bloodgroup in female

casualties.

Women, military and civilian, are becoming more frequent

victims of conflict. Approximately 85% of the American

population is Rh positive. Serious consequences to Rh

incompatible blood are rare in men. Data predict that 10% of
7.8

Emergency War Surgery

group O blood transfusions will be of Rh positive units to Rh

negative female recipients. An Rh negative woman transfused

with Rh positive blood is very likely (approximately 80%) to

produce anti-D (Rh positive) antibodies. This seroconversion

can jeopardize a subsequent pregnancy when this Rh negative

mother, now sensitized by Rh positive transfusion, conceives

an Rh positive fetus. Chronic hemolytic disease of the

newborn may result.

Under no circumstances should a life-saving transfusion be

withheld because of Rh incompatibility; saving a life takes

precedence over Rh immunization.

Prevention: When the supply of group O blood permits, group

O Rh negative blood should be reserved for women.

 Massive transfusions.

ο Definition.

♦ >10 Units of PRBC’s in <24 hours.

♦ Whole body blood volume transfusion in a 24-hour

period.

ο Consequences of massive blood loss.

♦ Shock.

♦ Hypothermia.

♦ Acidosis.

♦ Decrease of coagulation factors.

♦ Decrease of platelets.

ο Consequences of massive blood transfusions.

♦ Dilution of coagulation factors.

♦ Dilution of platelets.

♦ Acidosis.

♦ Hypothermia.

♦ Hypocalcaemia (citrate toxicity) associated with rapid

transfusions.

ο For every 10 units of PRBCs give:

♦ 4 units of FFP.

♦ 1 unit of platelets (6 pack of 1 aphresis unit).

♦ Consider 1 dose of cryoprecipitate (10 single units of Cryo).

ο What blood to use?
7.9

Shock and Resuscitation

♦ Type specific if at all possible.

♦ O positive (preferred) in males and postreproductive

females.

♦ O negative (if available) in females of reproductive age.

♦ If still using O after 8 units, stick with O, even if blood

type is determined. Stick with O until the patient’s

forward and back typed appropriately.

ο Which FFP to use?

♦ There is no such thing as emergency release FFP.

♦ Type specific if at all possible.

♦ AB when in doubt.

♦ A as a second choice.

♦ Unless you KNOW that the patient is Type O blood,

DO NOT use Type O FFP.

 Walking blood bank.

When standard blood component therapy is unavailable, the

use of fresh whole blood can be lifesaving. Because whole blood

contains clotting factors, it is effective for treating dilutional

coagulopathy associated with massive blood loss and fluid

resuscitation.

ο Equipment.

♦ Blood recipient set (bag), indirect Tx Y-type (NSN 6515

01 128 1407).

♦ Stopcock, IV therapy 3 way, with Luer lock (NSN 6515

00 864 8864).

ο Cautions.

♦ Field conditions increase the risk of bacterial contamination.

♦ Definitive testing of blood for transfusion virus diseases

is not available.

♦ “Dog tag” blood typing wrong 2%–11% of the time.

♦ Donor performance may be impaired by donation.

◊ Good for small numbers of patients—large numbers

lead to doubling of unit ineffectiveness.

◊ Should not be the “default” answer for standard

blood program planning.

◊ Donate only once a month.

◊ Avoid donation at high altitudes.
7.10

Emergency War Surgery

Even in an emergency, try to get regularly issued blood

products.

◊ Women—ideally on supplemental iron before/after

donation.

ο Planning.

♦ Predeployment.

◊ Develop a current prescreened donor roster.

Blood type and Rh.

Nonreactive transfusion transmissible disease

tests (if available).

♦ Onsite.

◊ Update prescreening donor roster.

Tent/cot location.

Duty location.

 Emergency (no roster in place).

ο Establish blood types with local testing or previous donor

history.

ο Choose prior blood donors in preference to nondonors

because they have been tested for the infectious diseases

in the past.

ο Rely on “dog tags” only as a last resort.

ο Draw only type “O” universal donors in mass casualty

situations to reduce the confusion of handling.

ο Draw universal or type specific donors in case of single

patient incidents. (Type O donors are 46% of the US

population.)

 Procedure for walking blood bank.

ο Clean donor’s arm with povidone iodine for at least 1

minute.

ο Draw the blood from an arm vein into an unexpired, intact

commercial blood bag.

ο The bag has a 600 ml capacity and contains 63 mL of CPD

or CPDA-1 anticoagulant.

ο Draw about 450 mL, a “pint,” so that the bag is almost full.

ο Draw tubes for typing, cross-matching, and transfusion

transmissible disease testing (if available).
7.11

Shock and Resuscitation

ο Send tubes to a supporting laboratory (if available). Even

after-the-fact testing is useful to provide reassurance of

safety or explanations of untoward events.

ο Label the bag clearly with blood type and donor

identification information.

 Whole blood crossmatching.

ο The white tile method uses a drop of the donor blood

mixed with the recipient serum on a white ceramic tile

and is examined in 4 minutes.

ο If no agglutination occurs, the blood is suitable for

transfusion into that recipient. A hand lens may be useful.

 Storage.

ο Keep at room temperature no longer than 24 hours.

ο Blood stored warm for more than 24 hours has a significant

risk of bacterial growth and clotting factors will be lost. If

the blood has been kept at room temperature for less than

8 hours, it can be kept in a refrigerator or on wet ice for up

to 3 weeks.

ο Although RBCs remain viable, platelets may become

inactive in whole blood stored cold (1°C–10°C) for greater

than 24 hours, losing one of the main benefits of fresh

whole blood.

ο Ensure that anesthetist/anesthesiologist and surgeon are

aware that this is an emergency-drawn unit and tell them

the history of the unit.

ο After 24 hours, destroy warm-stored, whole-blood units.

(Stateside hospitals would do so after exceeding 10°C for

30 minutes.) They are no longer safe or fresh. You may

save cold-stored units until a regular supply of tested blood

is reestablished.

ο Keep a record of donors and patients transfused so they

can be tested on return to stateside.

ο Keep a record of number of units transfused, donor names,

and outcome.

 Autotransfusion.

ο Blood collected into sterile containers (eg, suction, chest

tube, among others) may be returned to the patient through

a blood filter.
7.12

Emergency War Surgery

ο Blood from sterile cavities, such as the chest or abdomen

without visceral injuries is preferred.

ο Blood from contaminated abdominal wounds can be used

at an increased risk of systemic infection.

ο Blood may be filtered through sterile gauze as a field

expedient method.

The Future

Because the definition of shock is inadequate oxygenation at

the cellular level, the most ideal fluid would provide volume

expansion and oxygen-carrying capacity. For this fluid to be

useful in deployed settings it needs to be stable at a variety of

temperatures and have a low-risk profile. Hemoglobin based

oxygen carrying compounds (HBOCs) currently under

investigation may be such fluids. There are HBOCs derived from

either bovine or human sources that require no refrigeration,

have a shelf life of up to 3 years, are disease free, and require no

crossmatching.