Note: The 2019 Update unfortunately did not record the images correctly so it is necessary to look at the power point slides separately in order to be able to see them (unless you use a magnifying glass!).
Shock: Inadequate organ perfusion and tissue oxygenation
4 categories of shock: Hypovolemic (hemorrhagic, dehydration), distributive (septic, neurogenic, anaphylactic), cardiogenic, obstructive (PTX, cardiac tamponade, PE)
Hypovolemic shock
Most common type of shock in trauma, usually hemorrhagic, other causes include volume depletion from burns, etc.
Four classes:
Class 1 - EBL <15% (<750 mL), nrml UOP, nrml HR, nrml BP
Class 2 - EBL 15-30% (750-1500 mL), 20-30 mL/hr UOP, 100-120 HR, nrml BP
Class 3 - EBL 30-40% (1500 -2000mL), 5-15 mL/hr UOP, 120-140 HR, narrow PP
Class 4 - EBL >40% (>2000 mL), 0 mL/hr UOP, >140 HR, Hypotensive
*** unreliable due to paradoxical bradycardia, baseline bradycardia (athletes), baseline hypertension, beta blockers, ca-channel blockers, DI
Hypotension, tachycardia, low UOP in trauma is hemorrhage until proven otherwise
Acute management A (done) - B (done) - C (focus of hypovolemic shock)
2 large bore IVs
Assess: radial pulse = SBP 90+, femoral pulse = SBP 70+, carotid pulse = SBP 60+
UOP is most sensitive marker
Initial fluid challenge = 1 L warmed isotonic crystalloid (LR or NS)
Early blood with class 3 or 4 shock
Look for and control source
Assess response and give more fluid if necessary to normalize UOP, HR, BP
Benefits of crystalloids: maintenance of cerebral blood flow, maintenance of renal blood flow, improved venous return, decreased viscosity (help microvascular flow, but bad in short term), replenishment of ECF losses
Downsides of crystalloids: dilution (RBCs, Platelets, Coag factors), bleeding recurrence, edematous complications
Goal of acute fluid resucitation = preserve blood flow to vital organs (brain, heart, etc...) while injury corrected
Problem with acute fluid resucitation = dilution and increased bleeding in patients with ongoing sources fo hemorrhage
Physics of bleeding - Rate of leakage = area of vascular defect x (intramural pressure - extramural pressure) x V2 / density of fluid
HISTORIC PUBLICATIONS
"Inaccessible or uncontrolled sources of blood loss should not be treated with intravenous fluids until the time of surgical control"
- Cannon WB, Fraser J, Cowell EM. The preventive treatment of wound shock. JAMA 1918
"...though shock may be temporarily alleviated by transfusion, it can not be arrested or overcome; resuscitation divorced from surgery is folly"
- Ogilvie, WH; "abdominal wounds in the western desert"; SG&O, March 1944
Origins of crystalloid resuscitation in trauma:
Wiggers CJ. Physiology of Shock. New York, Commonwealth Fund, 1950, pp 121-146
Wiggers method - 30 dogs bleed into shock then resuscitated with LR + Blood (did the best), Plasma + blood, Blood alone (did the worst) - showed LR was valuable
Shires T, Coln D, Carrico J, Lightfoot S. Fluid Therapy in Hemorrhagic Shock. Arch Surg 1964
Emphasis to replete ECF along with lost blood
While the replacement of blood loss with whole blood remains the primary treatment of hemorrhagic shock, adjunctive replacement of the coexisting functional extracellular fluid volume deficit with a balanced salt solution appears to be of value
Dillon J, Lynch LJ, Myers R, Butcher HR, Moyer CA. A Bioasay of Treatment of Hemorrhagic Shock. Arch Surg 1966
Mis-application of controlled hemorrhage models to patients with uncontrolled hemorrhage
Controlled hemorrhage (like Wiggers method): When patients reach ED, start two large bore IV and infuse 1-2 L of LR in 45 minutes
Uncontrolled hemorrhage: uniform findings of increased bleeding and mortality with IVF vs without
Mattox KL, Bickell W, et al. prospective MAST study in 911 patients. J Trauma 1989
Mast trousers increased BP but no improved survival
Re-appraisal of accepted dogma of resuscitation to normal BP
Uncontrolled hemorrhage model by Bicknel WH, Bruttig SP, Millnamow GA, O'benar J, Wade C. The detrimental effects of intravenous crystalloid after aortotomy in swine. Surgery 1991;
Uncontrolled hemorrhage model = aortotomy and let them bleed
80 mL/kg LR 6 minutes after aortotomy at 9 ml/kg/min
2142 +/- 178 cc blood loss, 100% mortality, gelatinous clot)
VS.
Control with no IVF
783 +/- 85 cc blood loss, 0 mortality, adherent clot
William Bickell, Matthew Wall, Paul Pepe, R Martin, V Ginger, M Allen, K mattox. Immediate versus Delayed fluid resuscitation of hypotensive patients with penetrating torso injuries. NEJM 1994.
Penetrating torso trauma with SBP < 90
Even days standard ATLS approach, odd days delayed resuscitation
Delayed resuscitation:
IVF at KVO, once in OR - resuscitate to endpoints of SBP 100+, UOP 50 mL/hr, Hct >25
Volumes Administered lower in delayed
Complications lower in delayed
Survival improved in delayed
Dutton RP, Mackenzie CF, Scalea TM. Hypotensive Russcitation during Active Hemorrhage: Impact on In-Hospital Mortality. J Trauma 2002
110 blunt and penetrating trauma patients with SBP <90 at Baltimore Shock Trauma Center
No difference between resuscitation to SBP >100 vs. >70
Major flaw = not randomized = selection bias in patients entered into study (overall 8% mortality vs. 34% in Houston study)
Conclusion - multiple lab models and only good prospective trial demonstrate detriment from large volume of isotonic crystalloids in uncontrolled hemorrhage, once hemorrhage is controlled then traditional teachings apply
Future questions - benefit from smaller volumes? benefit from different fluids?
2001 consensus summary - combat casualty --> control bleeding with pressure to bleeding site/consider tourniquet, transport to higher level of care --> vital signs and mental status -->
Abnormal --> obtain IV access and administer fluids (7.5% hypertonic saline up to 500 cc), if more fluids needed, switch to isotonic or colloid fluids
Palp radial pulse/ good mentation --> obtain access but withhold fluids, encourage oral fluids
Give in measured fluids
Colloid vs. Crystalloid
Colloid advantage: remains intravascular better (has not translated to improved clinical outcomes), weighs less
Colloid disadvantages:
hespan - coagulopathy - decreased vWF, FVIII
Albumin - increased ARDS
Both crystalloids and colloids prime neutrophils
Cochrane Review Conclusion 2011: "There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns, or following Surgery. As colloids are not associated with an improvement in survival and as they are more expensive, it's hard to see how their continued use in these patients can be justified outside the context of RCTs."
If you're going to use colloid - higher molecular weight hydroxyetastarch HES (eg Hextend, Hespan) associated with decreased vWF adn FVIII --> coagulopathy risk with 1 L
Voluven (low MW HES) not associated with coagulopathy and provides more prolonged volume expansion
Kiraly LN..., Schreiber MA. Resuscitation with NS vs. LR modulates hypercoagulability and leads to increased blood loss in an uncontrolled hemorrhagic shock swine model. J Trauma 2006
Resuscitation with NS modulates coagulability after trauma and results in increased fluid requirmeents. These changes are associated with increased blood loss after injury and uncontrolled hemorrhage
Mechanism: induced metabolic acidosis, vasodilatory effect of NS, lack of Ca++ ions in NS,
LR therefore preferred over NS
LR causes neutrophil activation after hemorrhagic shock
Components of Ketone and LR solutions:
Ketone Ringer's: 3-D-beta-hydroxybuterate: 28mm, Sodium 130mm, potassium 4mm, Calcium 1.5mm, Chloride 109mm, pH 7.5, Osmolarity 275
DL-Lactated Ringer's: DL-Lactate: 28mm, Sodium 130mm, potassium 4mm, Calcium 1.5mm, Chloride 109mm, pH 7.5, Osmolarity 275
L-Lactated Ringer's: L-Lactate: 28mm, Sodium 130mm, potassium 4mm, Calcium 1.5mm, Chloride 109mm, pH 7.5, Osmolarity 275
Hypertonic saline resuscitation attenuates neutrophil lung sequestration and transmigration by diminishing leukocyte-endothelial interactions in a two hit model of hemorrhagic shock and infection
HTS failed to show early improved survival
Advantages in head trauma pts and prehospital setting - decreased cerebral edema, decreased dilution, easier logistically, prolonged resuscitation, less immune stimulations, ?hypertonic saline/colloid combo useful?
2010 concensus conference TCCC Resuscitation Guidelines - hypotensive resuscitation - give fluid only if the patient has an altered mental status or an absent or weak radial pulse - give fluid (500mL of Hextend or LR for civilians) and repeat x1 if the patient is still in shock - hemorrhage controll is paramount
Blood - The Good Colloid
Good volume expander
Improves/preserves O2 carrying capacity
Disadvantages 1/500,000 fatal hemolytic reactions, 1/500,000 anaphylactic reactions, 1/500,000 HIV infection, 1/200,000 viral hepatitis, dilutional coagulopathy, hyperkalemia, hypocalcemia, increased ARDS risk
Transfusion Hx
WW1 - first widespread use of whole blood transfusion
WW2 - initial emphasis on plasma replacement - worsened outcomes
1950-1970s - whole blood fractionation techniques
1970s - component therapy becomes standard of care when whole blood not available
Advantages of fresh whole blood - Warm, no degradation of O2 carrying capacity, whole (contains clotting factors, platelets in appropriate ratios), available when components aren't, less waste, less total donors exposed, usable after 8 hrs at room temperature then refrigerate and use as pRBC
Disadvantages of fresh whole blood - logistics of screening for HIV, Hepatitis, etc.; graft vs host phenomena (fever); potentially increased incidence of Abs due to lack of leukoreduction
Walking blood bank - type specific whole blood after 4 u pRBC, pre-screened donor pool
Coagulopathy of trauma
Acidosis and hypothermia --> Impaired clotting factor function, impaired platelet function
High ISS --> CNS injuries --> Increased TF release -->DIC
--> Long bone fxs --> fat embolism
Hypotension --> increased IVF and pRBCs --> dilution of clotting factors and platelets
Massive transfusion protocols are based on dilutional kinetics with FFP being recommended after 4-6 units of pRBCs = underestimation of coagulopathy present
25% of traumas are coagulopathic on admission - 11% w/ Injury Severity Score (ISS) < 15, 33% w/ ISS >15, 62% w/ ISS >25 (correction in class)
Independent of IVF received in field
Correlates w/ mortality
Majority (90%) are prothrombotic need anticoagulation to avoid DVT/PE
Mintority (<10%) are coagulopathic leading to bleeding/death
Early FFP -
coagulopathy persisted even after acidosis, hypothermia and hypotension resolves
Allow early treatment of coagulopathy with 1 u FFP for each unit of pRBCs - recreate whole blood from components
Early Platelets -
More difficult to assess need/utility - no practical functional assay (TEG may be exception), variable rates of splenic sequestration/release, concern for Ab Formation
Two series of trauma cases correlated mortality with lower platelet counts and demonstrated survival benefit with 0.8/1 : platelets/pRBCs new recommendations say 1u / each pRBC (4 pack q4)
Trauma w/ potential for hemorrhagic shock
--> SBP>90 and good mentation -->IV access to KVO --> source control
-->SBP < 90 or poor MS secondary to hypovolemia --> 1L LR IV Bolus (may repeat x1) --> pRBCs
Coagulopathic, ISS>15, Temp <35 or pH <7.3/BD-5 --> trauma transfusion protocol --> source control
Otherwise --> source control
MC Trauma Transfusion Protocol
Warm patient aggressively (room temp, bair huggers, all warm fluids), reinfuse any hemothorax, cell saver if possible, minimal crystalloid use (<1 L for each 4 u pRBCs), 1 u of FFP w/ each u of PRBCs, 4 pack of platelets with each 4 units pRBCs/FFP