7/4/2015 of care for a patient with altered tissue perfusion. –integrate lactate levels, base...

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Leanna R. Miller, RN, MN, CCRN – CSC, PCCN – CMC, CEN, CNRN, NP

Education Specialist LRM Consulting

Nashville, TN

Optimizing Outcomes in Shock

• Behavioral Objectives

– Evaluate the effect of therapeutics on the delivery

of oxygen to the cells.

– Correlate physical signs and symptoms, diagnostic

studies, and hemodynamic alterations to develop a

plan of care for a patient with altered tissue

perfusion.

– Integrate lactate levels, base excess, and oxygen

deliver and consumption parameters into clinical

decision making and selection of therapeutic

modalities.


Definition

tissue perfusion that is inadequate to maintain normal metabolic and nutritional functions

if unresolved, progresses to an irreversible state that results in multisystem organ failure & death


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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


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• Vital Signs

• Hemodynamic Parameters

• Global Indices

• Organ Specific Indices

Parameters Used to Assess Shock


Assessing Shock

• Majority of patients are still in compensated shock even though VS, CI, UO & SvO2 have returned to normal

• 80% of trauma patients with normal BP showed signs of hypoperfusion to non vital organs


Assessing Shock

• 85% has increased lactate and

decreased SvO2 even though HR,

BP, UO were normal

• Compensatory mechanisms mask

true organ perfusion


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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

parameter in 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


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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



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SvO2 or ScvO2

–SaO2

–Hgb

–CO

–VO2


O2 Extraction Ratio

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


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Supranormal Values

CI 4.5 L/min/m2

DO2I 600 L/min/m2

VO2I 170 mL/min/m2


inadequate pulmonary

gas exchange

inadequate CO

inadequate oxygen

carrying capacity



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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


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volume

inotropes

vasoactive drugs

reassess peripheral

circulation

Therapeutics


Identify potentially inadequate

DO2 states

–clinical evidence of shock

–SvO2 < 60%

–O2ER > 30%


Identify pathological

flow dependency state

• DO2 with fluids

or inotrope

• recalculate VO2

• VO2 > 10-20

L/m2


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ensure accurate parameters

index to body size

eliminate sources of error

use parameters with < 5-10% variance

Calculations of O2 Delivery & Consumption


calculate actual VO2

estimate potential VO2

(look at factors that

demand)

O2 Supply / Demand Determinants


[email protected]


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delivery needs to

by at least same

percentage as demand

O2 Supply / Demand Determinants


Global Indicators of Perfusion

• SvO2, ScvO2

• Serum lactate

• Base Excess

• End Tidal CO2 monitoring

(PETCO2)


60 – 75%

75 – 80%

SvO2

ScvO2


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Problems with SvO2, ScvO2

• reflects venous blood O2 saturation from entire body – not organ specific

• invasive monitoring

• does not reflect actual cellular utilization


may be or normal in

presence of hypoxia

not reliable reflection

of tissue hypoxia

reliable indicator of

tissue perfusion

Lactate Levels


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indirect measure of

oxygen debt

time to normalization is

predictive of outcome

more helpful if used as

trend

Lactate Levels


liver is efficient at

metabolizing lactate

acute alcohol intoxication

affects lactate metabolism

liver injury will slow lactate

clearance

Lactate Levels


arterial more precise

normal < 1 mEq/L

> 3 - 4 mEq/L significant hypoperfusion – associated with higher mortality

will decrease 5 - 10% / hr when appropriate therapy used

Lactate Levels


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Lab Studies – Base Excess

Normal value: - 2 to + 2

reflects the extent to which the body buffers have been exhausted

rapidity of normalizing base deficit decreases morbidity & mortality


Lab Studies – Base Excess

values

- 2 to – 5 mild

- 6 to – 15 moderate

- 16 or higher severe

global indicator

trending is best use of info

more prognostic if used with lactate


PETCO2

• PETCO2 reflects carbon dioxide

at end expiration

• Normal is 35 – 45 mmHg

• PaCO2 – PETCO2 gradient is

2 – 5 mmHg

• PaCO2 is usually higher

• Inverse relationship with VE

– VE, PETCO2

– VE, PETCO2


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Assessment of Blood Flow

• in systemic blood flow

pulmonary blood flow

• PETCO2 is decreased

• Shock

– PETCO2

• Cardiac Arrest

– Absent or very low PETCO2

• ROSC

– Return to normal PETCO2


Tonometry

pHi

early warning of inadequate splanchnic tissue oxygenation

low pH = poor prognosis (consistently < 7.3)


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


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StO2


StO2

.75 - .90


O2 demands are 30-50%

triggers systemic inflammatory

response

Trauma


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Hgb/Hct < 11/33 is associated with delivery-dependence

mortality if therapeutic targets reached < 12 - 24 hours

Trauma


CI > 4.5

DOI2 700

VOI2 170

Trauma


46 - year old male

– motor vehicle crash

– injuries: aortic disruption, severe bilateral pulmonary contusions, bilateral rib fractures, splenic fracture

– traumatic shock due to injuries

Case Study


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Which hemodynamic

findings are abnormal?

Case Study


HR 52

BP 122/64/82

CVP 10

Case Study


HR 52

BP 122/64/82

CVP / PAOP 10/11

CI 4.6

RVSWI / LVSWI 17/61

PAP 46/22/32

Case Study


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EDV / EDVI 237/107

EF 60%

O2ER 26.8

SvO2 .74

DO2 / DO2I 1603/722

VO2 / VO2I 430/194

Case Study


ABGs (.40 FiO2)

pH 7.31

pCO2 42

pO2 157

SaO2 .99

HCO3 20.8

SvO2 74%

P/F ratio 314.0

Case Study


Lab Values

Hgb 12.1

Hct 31.0

Magnesium 1.7

Lactate 5.1

Base Excess -5.1

StO2 72%

Case Study


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Does this patient need

further resuscitation?

Case Study


• 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?

StO2 and Hemodynamic Monitoring


StO2 and Hemodynamic Monitoring

• 48 yr with GSW to head

• Levophed at 50 mcg

• BP 114/74

• StO2 – 91

• Lactate – 5.2

• Does he need further treatment?

–What BP is really needed


http://cdn3.kevinmd.com/blog/wp-content/uploads/gun-shot-in-head.jpg?e8bd46

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Lactate Base Excess ScvO2 StO2

Early Early Delayed Early

Global Global Global Organ Specific

Invasive Invasive Invasive Non-invasive

Intermittent Intermittent Continuous Continuous

Delayed Info Delayed Info Real – time Real – time

Multiple

Variables

Multiple

Variables

Multiple

Variables

Specific

Requires additional info to direct appropriate interventions




7/4/2015 of care for a patient with altered tissue perfusion. –integrate lactate levels, base...

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