Leanna R. Miller, RN, MN, CCRN,-CMC, PCCN-CSC CEN, CNRN, CMSRN, NP
Education Specialist
LRM Consulting
Nashville, TN
Definition
 tissue perfusion that is
inadequate to maintain
normal metabolic and
nutritional functions
 potentially fatal if not
identified & treated
Introduction
 12% to 18% of patients
presenting initially in severe
shock have increased
mortality or morbidity related
to secondary organ failure
Clinical Signs of Shock
Preterminal Stages
 severe hypotension
 agonal respirations
 thready pulse
 tachy or bradydysrhythmias




Shock Index
HR / systolic blood pressure
inversely related to LVSW
abnormal > 0.9
application: persistently abnormal
shock index in patient with normal
VS suggests need for more
invasive monitoring
Rady (1992) Resuscitation 23:227 - 234

most important
feature to the care of
a critically ill patient
is delivery of oxygen
to the cells
 CO X CaO2 X 10
 CaO2 = Hgb x SaO2 x 1.38
 Normal 900 - 1100 mL/min
 DO2I = 360 - 550 mL/min/m2



oxygen consumption
CO x (SaO2 - SvO2) Hgb x 1.38 x 10
VO2 = 220 - 290 mL/min
VO2I = 108 - 165 mL/min/m2
 normally
VO2 is
25% of DO2
 SvO2
• SaO2
• Hgb
• CO
• VO2





amount of oxygen extracted
from blood as it passes
through the tissues
(CaO2 - CvO2 )/ CaO2
values > 0.30 abnormal
> 0.35 serious
normal 22% to 27%
>
0.35
• increased VO2
• decreased DO2
• both
CI 4.5
2
 DO2I 600 L/min/m
 VO2I 170 mL/min/m2

2
L/min/m



inadequate pulmonary
gas exchange
inadequate oxygen
carrying capacity
inadequate CO

conditions and
activities that alter
demand and
consumption

critically low DO2
vasodilated state
vaso-obstructed state
diffusion distances

affinity of Hgb for O2






increased extraction
once extraction maximized –
consumption is dependent
on delivery
demand > consumption =
O2 debt



may be  or normal in
presence of hypoxia
not reliable reflection
of tissue hypoxia
reliable indicator of
tissue perfusion




arterial more precise
normal < 1 mEq/L
> 3 - 4 mEq/L significant
hypoperfusion
will decrease 5 - 10% / hr
when appropriate therapy
used



pHi
early warning of
inadequate splanchnic
tissue oxygenation
low pH = poor prognosis
(consistently < 7.3)
Lab Studies
 Normal value: - 2 to + 2
 reflects the extent to which
the body buffers have been
exhausted
 rapidity of normalizing base
deficit decreases morbidity
& mortality
Most Reliable Perfusion
Markers
 Serum lactate
 Base deficit
n
n
n
StO2
near infrared light illuminates
tissue
light scatters and is absorbed
differently by oxygenated and
deoxygenated hemoglobin in
the microcirculation
light returns to sensor and is
analyzed and displayed as %
StO2
StO2
StO2
.75 - .90
volume
 inotropes
 vasodilators
 assess peripheral
circulation


Identify potentially
inadequate DO2 states
• clinical evidence
of shock
• SvO2 < 50%
• O2ER > 30%

Identify pathological
flow dependency state
– DO2 with fluids or
inotrope
–recalculate VO2
–VO2  > 10-20 L/m2




ensure accurate
parameters
index to body size
eliminate sources of
error
use parameters with
< 5-10% variance
calculate actual VO2
 estimate potential VO2
(look at factors that
demand)

needs to 
by at least same
percentage as demand
 delivery
O2 demands are 
30-50%
 triggers systemic
inflammatory
response

Hgb/Hct < 11/33 is
associated with deliverydependence
  mortality if therapeutic
targets reached < 12 - 24
hours

 CI
> 4.5
 DOI2 700
 VOI2 170

46 - year old male
• motor vehicle crash
• injuries: aortic disruption,
severe bilateral pulmonary
contusions, bilateral rib
fractures, splenic fracture
• traumatic shock due to
injuries
Which hemodynamic
findings are abnormal?
HR
BP
RAP / PAOP
CI
PVRI / SVRI
RVSWI / LVSWI
PAP
67
122/64/82
10/11
4.6
143/317
17/61
46/22/32
EDV / EDVI
EF
O2ER
SvO2
DO2 / DO2I
VO2 / VO2I
237/107
60%
26.8
.74
1603/722
430/194
ABGs (.40 FiO2)
pH
pCO2
pO2
SaO2
HCO3
SvO2
P/F ratio
7.31
42
157
.99
20.8
74%
314.0
Lab Values
Hgb
Hct
Sodium
Chloride
Magnesium
Lactate
Base Deficit
12.1
31.0
139
112
1.7
5.1
-5.1
What is the underlying
pathophysiology?
What is are the priority
interventions?
StO2 and Hemodynamic Monitoring
33 yr with GSW to chest
4 units of PRBC due to Hct of 27
SVO2 – 70 after blood administration
StO2 – 80%
Lactate 1.2
Does he need further treatment?