emergency ventilatory management of the critically ill...
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Emergency Ventilatory Management Emergency Ventilatory Management of theof the Critically Ill Critically Ill andand Injured:Injured:
Elemental or Detrimental?Elemental or Detrimental?
Presented at EMS TodayMarch 20, 2005
Presented at EMS TodayMarch 20, 2005
Copyright 2005 Ray Fowler MD, FACEPCopyright 2005 Ray Fowler MD, FACEPRay Fowler MD, FACEP
www.utsw.wswww.utsw.wswww.utsw.ws
That Brings Us to That Brings Us to TodayToday’’ s s
Sacred CowSacred Cow……
the
A-B
-C’s
!
Wha
t Abo
ut th
e“B”
Par
t?
Ass
iste
d B
reat
hing
with
PP
V
Res
cue
Bre
athi
ng...
Is It
Rea
lly N
eces
sary
?
Q: What are the Typical Teachings & Current National
Protocol Standards?
Q: What are the Typical Teachings & Current National
Protocol Standards?
A: 10-15 ml/kgTidal Volume &
15-20breaths/min Respiratory Rate
A: 10-15 ml/kgTidal Volume &
15-20breaths/min Respiratory Rate
Why
Do
We
Why
Do
We
Ven
tilat
e?V
entil
ate?
Copyright 2005 Ray Fowler MD, FACEPCopyright 2005 Ray Fowler MD, FACEPRay Fowler MD, FACEP
Oxygen-> lungs -> alveoli -> blood
muscles + organs
Oxygen
cells
Oxygen
Oxygen+
Glucose
energy
CO2
blood
lungs
CO2
breath
CO2
Oxygen and CO2Oxygen and CO2
Copyright 2005 Ray Fowler MD, FACEPCopyright 2005 Ray Fowler MD, FACEPRay Fowler MD, FACEP
Carbon dioxide physiology
Carbon dioxide physiology
CO2 + H2O H2CO3 H+ + HCO3-
Copyright 2005 Ray Fowler MD, FACEPCopyright 2005 Ray Fowler MD, FACEPRay Fowler MD, FACEP
Carbon dioxide physiology
Carbon dioxide physiology
• 0.03% concentration in air• Resting adult produces
2.5 mg/kg/min• In a 70 kg adult, that is about
175 mg per minute, or about 4% of a teaspoonful
• 0.03% concentration in air• Resting adult produces
2.5 mg/kg/min• In a 70 kg adult, that is about
175 mg per minute, or about 4% of a teaspoonful
Copyright 2005 Ray Fowler MD, FACEPCopyright 2005 Ray Fowler MD, FACEPRay Fowler MD, FACEP
Carbon dioxide physiology
Carbon dioxide physiology
• Transported in blood– 60-70% bicarbonate ion after
conversion in RBCs using carbonic anhydrase
– 20-30% bound to proteins (e.g., Hb)– 5-10% in physical solution (PCO2)
• Cleared by alveolar ventilation
Copyright 2005 Ray Fowler MD, FACEPCopyright 2005 Ray Fowler MD, FACEPRay Fowler MD, FACEP
Alveoli: The Place Where Gas Exchange Happens
Alveoli: The Place Where Gas Exchange Happens
OxygenationOxygenationvs.vs.
VentilationVentilationSaturating Red CellsSaturating Red Cells
vs.vs.
Clearing COClearing CO22
OxygenationOxygenation
Air MovementAir Movementandand
Blood FlowBlood Flow
THUS! CyanosisTHUS! Cyanosis……
An Air Movement ProblemAn Air Movement Problemoror
A Circulation ProblemA Circulation Problem
Wha
tW
hat ’’ s
an
Ade
quat
e T
idal
Vol
ume?
s an
Ade
quat
e T
idal
Vol
ume?
IT DEPENDS ON THE IT DEPENDS ON THE CLINICAL SITUATION!!CLINICAL SITUATION!!
10 m
l per
kg
(Int
ubat
ed, N
o P
EE
P, N
o D
iffus
e Lu
ng In
jury
)
Ven
tilat
ion
Ven
tilat
ion
Tid
al V
olum
eT
idal
Vol
ume
xx RR
RR
““ Ven
tilat
ion
Ven
tilat
ion
””
ME
AN
SM
EA
NS
RA
TE
!!R
AT
E!!
How
Fas
t H
ow F
ast
Sho
uld
You
S
houl
d Y
ou
Bre
athe
The
m?
Bre
athe
The
m?
Need to VentilateNeed to Ventilate
••COCO2 2 Production Production (depends upon O(depends upon O2 2 CConsumption onsumption
&& Venous ReturnVenous Return))
Hig
h V
entil
ator
y D
eman
d...
Hig
h V
entil
ator
y D
eman
d...
But Also:But Also:in very low flow statesin very low flow states
Oxygen ConsumptionOxygen ConsumptionBecomes Dependent Becomes Dependent onon
Oxygen Delivery...Oxygen Delivery...
For
Exa
mpl
e, C
PR
Cas
es...
Cardiac ArrestCardiac Arrest•• Little OLittle O 22 Delivery Delivery
& Consumption& Consumption
•• Little COLittle CO 22 Production Production & Venous Return& Venous Return
...Little Need to Ventilate...Little Need to Ventilate
0%
20%
40%
60%
80%
100%
120%
OO22 DeliveryDelivery( ml/min/kg )( ml/min/kg )
10 20 30 40
OO22MetabolizedMetabolized
(% of (% of baseline)baseline)
0%
20%
40%
60%
80%
100%
120%
A
B
OO22 DeliveryDelivery( ml/min/kg )( ml/min/kg )
10 20 30 40
COCO22ProductionProduction
(% of baseline)(% of baseline)
8 br
eath
s / m
in
Car
diac
Arr
est…
.
…Li
ttle
CO
2 E
xcre
tion
CP
R
Pul
ses
Ret
urn
Take HomeTake Home……
Ventilation Ventilation
Should Match Should Match PerfusionPerfusion……
The
“C
PR
Dile
mm
a”
Chest Compressions Chest Compressions & &
Coronary Perfusion PressureCoronary Perfusion Pressure5:15:1 RatioRatio
15:2 Ratio
20 mmHg20 mmHg
20 mmHg20 mmHg
40 mmHg40 mmHg
In Video Study of Lay Individuals Recently Taught 15:2 CPR ….
In Video Study of Lay Individuals Recently Taught 15:2 CPR ….
“Reality” CPR “Reality” CPR
…Took 15-16 Seconds to Deliver the2 Breaths
…Took 15-16 Seconds to Deliver the2 Breaths
Is There Evidence Is There Evidence That We Can That We Can
Breathe Less Often?Breathe Less Often?
Sanders, Sanders, et alet al•• 15:215:2 ((e.g.,e.g.,standard CPRstandard CPR))
•• 50:550:5 ((e.g.,e.g.,Great BritainGreat Britain))
•• CCCC ((chest compressionschest compressionsonlyonly))
•• 4 4 minmin CC CC onlyonly; ; thenthen 100:2100:2Porcine model of four different CPR techniquesAnnals of Emergency Medicine, Dec. 2002, pp 553-62Porcine model of four different CPR techniquesAnnals of Emergency Medicine, Dec. 2002, pp 553-62
Neurological Outcomes...Neurological Outcomes...•• 4 4 minmin CC CC onlyonly; ; thenthen 100:2100:2
----Did Significantly Better thanDid Significantly Better than
15:215:2 (e.g., standard CPR)(e.g., standard CPR)
•• CCCC (chest compression only) (chest compression only)
----Did Much WorseDid Much WorseAnnals of Emergency Medicine, Dec. 2002, pp 553-62Annals of Emergency Medicine, Dec. 2002, pp 553-62
Neurological Outcomes...Neurological Outcomes...•• CONCLUSIONCONCLUSION : In this experimental model of : In this experimental model of
bystander CPR, the group receiving bystander CPR, the group receiving compressions only for 4 minutes followed by a compressions only for 4 minutes followed by a compressioncompression--ventilation ratio of 100:2 achieved ventilation ratio of 100:2 achieved better better neurologicneurologic outcome than the group outcome than the group receiving standard CPR and CCreceiving standard CPR and CC--CPR. CPR. Consideration of alternative chest compressionConsideration of alternative chest compression--ventilation ratios might be appropriate.ventilation ratios might be appropriate.
Annals of Emergency Medicine, Dec. 2002, pp 553-62Annals of Emergency Medicine, Dec. 2002, pp 553-62
Sources of Sources of Ventilation:Ventilation:
•• Active Positive Pressure Active Positive Pressure
•• Chest CompressionsChest Compressions
•• GaspingGasping ((AgonalAgonal Breaths)Breaths)
Stopping to Breathe...Stopping to Breathe...
...Interrupts...InterruptsChest CompressionsChest Compressions
Idea
lC
PR
Idea
lC
PR
Rea
lC
PR
Rea
lC
PR
71%
19%
58%
42%
Normal BreathingNormal Breathing……•• Generates Negative IntraGenerates Negative Intra--
thoracic Pressurethoracic Pressure•• Pulls Lungs Open in a Pulls Lungs Open in a Specific Specific
ArchitectureArchitecture•• Enhances Venous Return Enhances Venous Return and and
Cardiac PreloadCardiac Preload
Ass
iste
d B
reat
hing
with
PP
V
PPVPPV……•• Generates Positive Generates Positive
IntrathoracicIntrathoracic PressurePressure•• Pushes Lungs Open in a Pushes Lungs Open in a
MaldistributiveMaldistributive MannerManner•• Diminishes Venous Return Diminishes Venous Return
and Cardiac Preloadand Cardiac Preload
PPV PPV Cardiovascular EffectsCardiovascular Effects
•• Obstructive Lung DiseaseObstructive Lung Disease•• HypovolemiaHypovolemia•• Circulatory CompromiseCirculatory Compromise
Worsened By...Worsened By...
So
Let’s
S
tudy
It!!
It’s
Not
Roc
ket
Sci
ence
!!
Dispatch Assisted CPR Instructions
Compressions Alone
vs
Standard ABC’s
Com
pres
sion
sA
lone
14.7
%vs
Sta
ndar
d
AB
C’s
10.4
%
Sur
viva
l...
But
Doe
s T
his
App
ly to
Chi
ldre
n?T
hink
Hyp
oxia
!!
How About How About Hypovolemic Hypovolemic
Patients?Patients?
Depends!Depends!
<---Breaths
Measuring Coronary Perfusion Pressure
Ventilated Pigs with Moderate Hemorrhage
Rate: 6 breaths x min-1 (2nd measurement)
one respiratory cycle= 10 sec.
Rate: 12 breaths x min-1
one respiratory cycle = 5 sec
s
Time-Averaged Coronary Perfusion Pressure = Area Under the Curve (in Pink)
RR = 6 / min RR = 12 / min
AufderheideAufderheide Study Study of Paramedicsof Paramedics
•• Averaged Averaged 3737±± 44 breaths/minbreaths/min
•• ReRe--trained at 12 / mintrained at 12 / min
•• Averaged Averaged 2222±± 33 breaths/minbreaths/min
CONCLUSIONS:Despite seemingly adequate training,
professional rescuers consistently hyperventilated patients
during out-of-hospital CPR.
CONCLUSIONS:Despite seemingly adequate training,
professional rescuers consistently hyperventilated patients
during out-of-hospital CPR.
And on the Road And on the Road to the to the
22nd Century...22nd Century...
…P
hren
icN
erve
Pac
emak
er?
Insp
irato
ryIm
peda
nce
Thr
esho
ld V
alve
-12
cm
H2O
HB
OC
HB
OC
-- 201
201
Let
Let ’’
s do
a
s do
a
Cas
e S
tudy
Cas
e S
tudy
Case #1Case #1……
•• 24 24 yoyo Male, Involved in MVCMale, Involved in MVC•• Altered MSAltered MS•• PERLA PERLA (but sluggish),(but sluggish),ThrashingThrashing•• 80/60, HR 130, pale80/60, HR 130, pale
Case # 1Case # 1……
•• Chest wall tenderChest wall tender•• Diminished BS on Right, dullDiminished BS on Right, dull•• Tender abdomenTender abdomen
Case # 1Case # 1……
•• Sick or not sick?Sick or not sick?•• REAL SICK, or REAL SICK, or kindakinda sick?sick?
Remember!!Remember!!Normal BreathingNormal Breathing……
•• Generates Negative Generates Negative IntrathoracicIntrathoracic PressurePressure
•• Pulls Lungs Open in a Pulls Lungs Open in a Specific ArchitectureSpecific Architecture
•• Enhances Venous Return Enhances Venous Return and Cardiac Preloadand Cardiac Preload
SO?????SO?????
How to assist How to assist ventilation ventilation
on this guy??on this guy??
MoribundMoribund Trauma Pt.Trauma Pt.
•• Little OLittle O 22 Transport Transport && ConsumptionConsumption
•• Little COLittle CO 22 Production Production && Venous ReturnVenous Return
Little Need to VentilateLittle Need to Ventilate
And ThereAnd There’’ s a Key s a Key Problem...Problem...
Positive Pressure Breaths Positive Pressure Breaths CanCanImpair Cardiac Output...Impair Cardiac Output...
...in the Face of Severe ...in the Face of Severe Circulatory CompromiseCirculatory Compromise
Moribund Trauma Moribund Trauma PatientPatient
•• Adequate Adequate Tidal VolumeTidal Volume
•• BreathBreath q 7 q 7 -- 10 seconds10 seconds
Tha
nk y
ouT
hank
you
for
your
kin
dfo
r yo
ur k
ind
atte
ntio
n!!
atte
ntio
n!!
ww
w.U
TS
W.w
sw
ww
.UT
SW
.ws
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