Transcript SHOCK AND RESUSCITATION Hugh M. Foy, MD Harborview Medical Center University of Washington Shock and Resuscitation Goal: understand the pathophysiology of shock and it’s treatment • Objectives: –

SHOCK AND
RESUSCITATION
Hugh M. Foy, MD
Harborview Medical Center
University 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
The Heart:
2-Sided Pump
• Right Side
– Compliant, flexible
– Low pressure,
variable volume
• Left Side
– Stiff, strong
– High pressure,
fixed volume
Like the colon?
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)
•
•
Mid-level
–
Kidneys- Juxtaglomerular
Apparatus
•
•
Stimulate Sympathetic Nervous
System
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
SHOCK
Acute Volume Loss
• Shock - Classes:
I
II
III
IV
0-15% blood loss
15-30%
blood loss
30-40%
blood loss
>40% blood loss
Response to Volume Loss
Type % blood loss
HR
BP
•
•
•
•
nl
+
+++
++++
nl
maybe
maybe
yes
decr
moot
<60Sys
“
I
0-15%
II 15-30%
III 30-40%
IV
>40%
Postural
Cap Ref
nl
nl
incr
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
Shires Shock Study
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%
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 Houston
Q: 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
scutaneous O2 Sat Monitoring
Tissue Oxygenation Measurements
*StO2 <75 severe shock
78% MODS
91% Dead
StO2 <75% in 1st hr.
* StO2 >75
88%
MODS free survival
Similar to Base Deficit
measurement
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.
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
Shock and Resuscitation:
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