SHOCK AND RESUSCITATION Hugh M. Foy, MD Harborview Medical Center University of Washington.

SHOCK AND RESUSCITATION

Hugh M. Foy, MDHarborview Medical

CenterUniversity of

Washington

Shock and Resuscitation

Goal: understand the pathophysiology of shock and it’s treatment

• Objectives:– Be able to categorize types of shock

– Understand mechanisms of adapting to volume loss of blood loss

– Demonstrate shock treatment: •lines, sites, types of fluid•End points of resuscitation•Complications of treatment

SHOCK: Definition

• Commonly misused– “psychogenic”– Webster: 12 different definitions

• 4: “the state of profound depression of the vital processes associated with reduced blood volume and pressure and caused usually by severe esp. crushing injuries, hemorrhage, or burns.”

“The rude unhinging of the machinery of life” Gross 1872

Types of Shock

• “Classic” Blalock 1937

– Hematogenic– Neurogenic– Vasogenic– Cardiogenic

Classification of Shock

• Low Cardiac Output states– Hypovolemic shock

• volume loss• Internal volume loss

– Cardiac shock• Impaired inflow• Primary pump dysfunction

• Impaired outflow– Low peripheral

resistance states• Neurogenic shock

– Loss of sympathetic tone

• Vasogenic Shock– Septic– Anaphylactic

Carrico: ACS Early Care of the Injured Patient 4th Ed.

The Circulatory System

• Components:– Heart (pump)– Blood Vessels– Blood

Circulation and Electricity

• Circulation– The flow of blood

• Electricity – The flow of electrons

• Ohms law: V= IR (Voltage = Current x Resistance)

BP = CO x SVR • (Cardiac Output x

System Vascular Resistance)

Circulation Schematic

• The Pump (heart)– 2 sided

• Anatomically looks parallel, BUT:

• Physiologically and in Actuality– Supplies 2 systems connected in series

2-Sided Pump

• Right Side– Compliant, flexible

– Low pressure, variable volume

• Left Side– Stiff, strong– High pressure, fixed volume

Like the colon?

The Heart:

The Circulatory System

• Multiple Parallel Circuits– Organized teleologically: • Prioritized supply

– Closest circuits get supplied first and foremost» Coronaries, Brain, Kidneys

– Distal circuits get shut down when volume low» Gut/Muscle, Skin

Circulatory Control Mechanisms

• Closest, fastest– Carotid Bodies

(Baroreceptors)• Stimulate Sympathetic

Nervous System

• Mid-level– Kidneys- Juxtaglomerular

Apparatus• Sense low flow and

stimulate Renin resulting in vasoconstriction (splancnic)

• Down-line– Adrenal Cortex

• Senses need for more Sodium and Fluid Re-absorbtion to deal with upright posture volume needs

Acute Volume Loss

• Shock - Classes:

I 0-15% blood lossII 15-30% blood lossIII 30-40% blood lossIV >40% blood loss

SHOCK

Response to Volume Loss

Type % blood loss HR BP Postural Cap Ref

• I 0-15% nl nl maybe nl

• II 15-30% + maybe yes nl

• III 30-40% +++ decr moot incr

• IV >40% ++++ <60Sys “ incr

Shock Resuscitation Study

Shires, et al• Bled dogs 40% blood volume– 100% mortality untreated

• Bled, then gave back blood– 80% mortality– Autopsy study

• Swollen muscle cells despite total volume loss

• Tagged RBCs, Na+, K+, Alb., and repeated the experiment

Results

• Na+ leaked into cells

• K+ leaked out of cells

• Albumin leaked into interstitial space

• Water followed Na+ • Translocated fluid 3 times the shed blood

• Measured composition of transloc. fluid

Shires Shock Study

Conclusions

• Translocated Fluid composition is LR

• Inadequate O2 delivery shuts down Na+/K+ pumps, making cells leaky

• Repeated the Experiment:– Gave Shed Blood plus 3 times volume of LR•Mortality decreased from 80 to 30%

Shires Shock Study

Treatment of Shock

• Recognize Type of Shock

• If definite pump failure and cardiogenic shock institute cardiac protocols

• Otherwise: 2 large bore, upper extremity lines and:– Volume– Volume– Volume

When in doubt, try a little more volume

Treatment of Shock

• Goal: Restore perfusion

• Method: Depends on type of Shock– Basically 2 kinds:

• Hypovolemic (hemorrhagic, septic, neurogen.)

• Cardiogenic (Impedence or primary Cardiac Failure)

Treatment:Cardiogenic Shock

• Oxygen by nasal cannula

• IV access– Pain medication– Nitrates prn-

• may need unloading only after volume status addressed

– Treat arrythmias– CPR as needed

Treatment of Shock

• Prioritized approach• Must address and treat sequentially:– PRELOAD– AFTERLOAD– PUMP

• QUESTIONs:– What type of fluid– How Much– End Point of Resuscitation

Resuscitation Fluids

• Blood• Lactated Ringers• Normal Saline• Colloids• Hypertonic Saline• Blood Substitutes

Treatment: Hemorrhagic Shock

• Large bore access – 2 upper extremity IVs– 16 gauge or larger

• Bolus therapy– 20 cc/kg– Adults- 2 liters

• Monitor Effect• Repeat if necessary• After 2nd bolus: need

blood txn – 10cc/kg

End Points of Resuscitation:

• Restoration of normal vital signs• Adequate Urine output

– 0.5 - 1.0 cc/kg/hr

• Tissue Oxygenation measurement• Adequate Cardiac Index• Normalization of Oxygen delivery DO2I• Normal Serum Lactate levels

none proven helpful, some deleterious

Englehart; Curr Op Crit Care; Vol 12(6), Dec 06, p 579-574

Evolution in Treatment Strategies

• Auto transfusion (“Cell Saver”)• Hyperdynamic “Supranormal”

Resuscitation (Shoemaker)• Less is More - Mattox• Trauma Vaccine - Vedder, et al.• Hypertonic Saline• Glue Grant-

– standardization, endpoints, genetics

Alternatives to Transfusion:

• Autotransfusion– Safe, warm, better 2-3 DPG levels

– Coagulation factors present

– 2 methods• Passive collection and anti-coagulant (chest tubes)

• “Cell Saver”- washes Red Cells– Contamination and Time issues in trauma

•Expensive, fussy, too slow in trauma, •Okay in elective, clean cases

Hyperdynamic “Supranormal” Resuscitation

• Swan Ganz Catheter

• Measure ratio of O2 delivery and consumption

• Push fluid resuscitation until no longer “flow dependent”

• Massive Edema can be lethal – (DaNang Lung, ARDS, MSOF, SIRS,

Abdominal Comp. Syn.Multiple synergistic factors: some influenced by ventilator strategy

Mattox in HoustonQ: Is less fluid better?

• Randomized pts. QOD • LR vs 250 cc. Hypertonic Saline/Dextran• 3% increase in survival in HSD (not significant)

• Trend in increase survival in penetrating trauma victims only

• Prospective trial showed only a trend in improvement, with low n of 48 pts

• May be beneficial with head injuries only

• Ann Surg 1991;213:482-491• Am J Surg 1989;157:528-34

“We’ll see”

Trauma Vaccine Trials

• Shock- “Ischemia-Reperfusion Injury”

* WBCs “up-regulated”

adhere to endothelium

* Damaged endothelium leaky

Create massive edema

Blocking adherence -mAb 60.3

-neutropenia protective against ARDS

- WBC surface adhesion molecules when blocked

decreases the edema and injury

- animal data encouraging

Human Trials unsuccessful

Vedder, et al: Blood, 15 2002, Vol 100, No. 6, pp 2077-80

HYPERTONIC SALINE WITH DEXTRAN (HSD)

7.5%saline with 6% dextran-70

• Less volume and weight to carry

• May reduce mortality

• Limits secondary brain injury

• Less activation of inflammatory cells

Harborview Study

• Double blind, randomized study• N = 209• Endpoint: ARDS free survival

– 250 ml 7.5% HTS/ 6% Dextran70 vs LR

• Findings:– No difference in population overall– Improvement in sickest patients (19%)

• > 10 units PCs required

• Bulger et al: Arch Surg. 2008; 143(2); 139-148

Shock-Treatment Algorithm

Transcutaneous O2 Sat Monitoring

Tissue Oxygenation Measurements

Cohn SM, Nathens AB, Moore FA, Rhee P, Puyana JC, Moore EE, Beilman GJ. J Trauma. 2007 Jan;62(1):44-54; discussion 54-5.

*StO2 <75 severe shock

78% MODS91% Dead

StO2 <75% in 1st hr.

* StO2 >7588%

MODS free survival

Similar to Base Deficit measurement

Blood Transfusion

• Blood Banks safer• Some risk unavoidable

– New viruses are inevitable

– False negative screening tests

• Independent risk factor for MSOD

• Time for cross-match delays Rx

The Search for Alternatives continues

Alternatives to Transfusion:

• Blood Substitutes: – Immediately available, storage easier, no need for compatibility testing, disease free

– Polymerized, Stroma-free Hemoglobin• 50 gm in 500 ml• No adverse effects up to 6 units• Slight increase in Bilirubin• Studies small, more needed

Gould:J Am Coll Surg 1998: 187:113-122

SUMMARY

• The Circulation is a Circuit• Volume is most often the answer• Lactated Ringers still the standard• More is better than less, maybe• New techniques:

– Hypertonic Saline- • okay in Head Injury• Less immunosuppression• Helpful in the sickest patients

– Better Indicators & Endpoints of Resuscitation

Shock and Resuscitation: