the use of volumetric capnography in the management of ...the

Volumetric Capnography: Clinical Applications

Volumetric Capnography: Clinical Applications

Donna Hamel, RRT, RCP, FAARCPediatric Critical Care Medicine

Duke Children’s HospitalDurham, N.C.

Donna Hamel, RRT, RCP, FAARCPediatric Critical Care Medicine

Duke Children’s HospitalDurham, N.C.

Pop Quiz!!!!Pop Quiz!!!!1. Pressure limited modes are best.

2. Volume limited modes are best.

3. Mixed modes should be used whenever possible.

4. Mixed modes are of absolutely no benefit.

5. I don’t care, I just do what the Doc orders.

1. Pressure limited modes are best.

2. Volume limited modes are best.

3. Mixed modes should be used whenever possible.

4. Mixed modes are of absolutely no benefit.

5. I don’t care, I just do what the Doc orders.

Guess what?Guess what?

To date, no literature exists that proves one mode is superior to another.

So if you answered 1 – 4 You are all right!

To date, no literature exists that proves one mode is superior to another.

So if you answered 1 – 4 You are all right!

However…. However….

If you answered # 5

Why can’t we find the ‘perfect’ mode?Why can’t we find the ‘perfect’ mode?

Injured lungs are not hemogenous. Not all patients respond the same even

given the same disease process. Dynamic properties of the lung make

optimizing ventilatory parameters an ongoing process.

Injured lungs are not hemogenous. Not all patients respond the same even

given the same disease process. Dynamic properties of the lung make

optimizing ventilatory parameters an ongoing process.

In response….In response….

New technology Ventilators with myriad ventilatory modes

and flow options.

Capability to sculpt each breath to meet the specific needs of individual patients.

Clinicians can now choose from a multitude of options when initiating & managing mechanical ventilation.

New technology Ventilators with myriad ventilatory modes

and flow options.

Capability to sculpt each breath to meet the specific needs of individual patients.

Clinicians can now choose from a multitude of options when initiating & managing mechanical ventilation.

But nowBut now

Clinicians must now choose from a multitude of options when initiating & managing

mechanical ventilation. How do we assess the effectiveness of our

choices? Arterial blood gases Pulse oximetry ETCO2 monitoring Volumetric capnography

Clinicians must now choose from a multitude of options when initiating & managing

mechanical ventilation. How do we assess the effectiveness of our

choices? Arterial blood gases Pulse oximetry ETCO2 monitoring Volumetric capnography

Volumetric CapnographyVolumetric Capnography

Overview with emphasis on SBCO2 waveform

Clinical significance Tidal volume delivery Efficacy of delivered breaths Extubation success indication Length of ventilation

Case series



Case series

What is volumetric capnography?What is volumetric capnography?

Integration of flow and carbon dioxide. Measures, calculates, and displays breath-

by-breath measurements throughout the entire respiratory cycle. Digital numeric display Multiple graphics Single breath waveform (SBCO2)

Multitude of information including VCO2

Integration of flow and carbon dioxide. Measures, calculates, and displays breath-

by-breath measurements throughout the entire respiratory cycle. Digital numeric display Multiple graphics Single breath waveform (SBCO2)

Multitude of information including VCO2

Volume-based CapnographyVolume-based CapnographyIntegration of flow and CO2

Volumetric capnographyVolumetric capnography

This integration allows for the display of breath by breath measurements throughout the entire respiratory cycle.

Data is both digitally and graphically displayed.

This integration allows for the display of breath by breath measurements throughout the entire respiratory cycle.

Data is both digitally and graphically displayed.

Graphical displaysGraphical displays

Graphics provide rapid assessment of various parameters.

Help generate and test hypotheses of patient management.

Monitor for the presence of adverse effects of mechanical ventilation.

Graphics provide rapid assessment of various parameters.

Help generate and test hypotheses of patient management.

Monitor for the presence of adverse effects of mechanical ventilation.

Graphical displayGraphical display

Trending bars Waveforms Flow loops Scalars

Trending bars Waveforms Flow loops Scalars

Graphical displaysGraphical displays

Trending bars Especially useful during the weaning phase

of ventilation Useful for assessing effects of PEEP

titration SBCO2 waveform

Consists of 3 distinct phases Useful in determining pathophyiology Instrumental in designing optimal treatment

strategies

Trending bars Especially useful during the weaning phase

of ventilation Useful for assessing effects of PEEP

titration SBCO2 waveform

Consists of 3 distinct phases Useful in determining pathophyiology Instrumental in designing optimal treatment

strategies

SBCO2 MeasurementsSBCO2 Measurements CO2 elimination (VCO2) Alveolar ventilation (MValv) Deadspace ventilation (Vd/Vt) Assess pulmonary capillary blood flow

CO2 elimination (VCO2) Alveolar ventilation (MValv) Deadspace ventilation (Vd/Vt) Assess pulmonary capillary blood flow

%CO2

ExhaledVolume

Exp

ired

CO

2 I II

VT

III

SBCO2 waveformSBCO2 waveform

Three distinct phases

SBCO2 WaveformSBCO2 Waveform

Exp

ired

CO

2I

VTVT

Phase I = large airway ventilation


Exp

ired

CO

2E

xpir

ed C

O2 II II

VTVT

Phase II = mixed large airway and alveolar ventilation

Phase I = large airway ventilation


Exp

ired

CO

2I II

VT

Phase II = mixed large airway and alveolar ventilation Phase I = large airway ventilation

III

Phase III = exhaled volume of alveolar gas


Exp

ired

CO

2I II

VT

Phase II = pulmonary perfusion Phase I = dead space

III

Phase III = gas exchange

Phases of SBCO2 waveformPhases of SBCO2 waveform

Phase 1: represents gas exhaled from the upper

airways which generally is void of carbon dioxide

Phase 2: transitional phase from upper to lower

airway ventilation and tends to depict changes in perfusion

Phase 3: area of alveolar gas exchange

representative of gas distribution

Phase 1: represents gas exhaled from the upper

airways which generally is void of carbon dioxide

Phase 2: transitional phase from upper to lower

airway ventilation and tends to depict changes in perfusion

Phase 3: area of alveolar gas exchange

representative of gas distribution

Clinical relevanceClinical relevance

↑ phase 1 indicates ↑ in anatomic dead space

ventilation (VDANA) phase 2

depicts in perfusion ↑ phase 3

indicates a mal-distribution of gas

↑ phase 1 indicates ↑ in anatomic dead space

ventilation (VDANA) phase 2

depicts in perfusion ↑ phase 3

indicates a mal-distribution of gas


Overview with emphasis on SBCO2 waveform Clinical significance

Tidal volume delivery Efficacy of delivered breaths Extubation success indication Length of ventilation

Case series



Case series

Tidal Volume DeterminationTidal Volume Determination

The current practice of ventilating with low lung volumes makes accurately determining delivered tidal volume essential.

The current practice of ventilating with low lung volumes makes accurately determining delivered tidal volume essential.


Delivered tidal volume can be determined at two different locations:

at the expiratory valve of the ventilator

at the ETT with a pneumotach

Delivered tidal volume can be determined at two different locations:

at the expiratory valve of the ventilator

at the ETT with a pneumotach


Measuring tidal volume at the expiratory valve of the ventilator does not account for the volume “lost” due to the distensibility of the ventilator circuit.

Measuring tidal volume at the expiratory valve of the ventilator does not account for the volume “lost” due to the distensibility of the ventilator circuit.


Can you calculate the tidal volume “lost” due to the distensibility of the ventilator circuit and compensate for it?

Can you calculate the tidal volume “lost” due to the distensibility of the ventilator circuit and compensate for it?

Calculated effective Vt = Vt at exp valve - [circuit comp x (PIP - PEEP)]

ventilator

inspiration

expirationETT

EtCO2 adapter

flow/pressuretransducer

pneumotachometer

Results: Infant CircuitResults: Infant Circuit

Vt (ml) p

Exp valve Vt 70.4 ± 31.1

Calculated Vt 59.2 ± 28.8 < 0.0001

Pneumotach Vt 39.4 ± 21.5 < 0.0001

Vt (ml) p

Exp valve Vt 70.4 ± 31.1

Calculated Vt 59.2 ± 28.8 < 0.0001

Pneumotach Vt 39.4 ± 21.5 < 0.0001

n = 70

The expiratory Vt measured at the ETT was on average 56% of that measured at the expiratory valve of the ventilator. Cannon, AJRCCM, 2000.


0

50

100

150

200

0 20 40 60 80 100 120

0

50

100

150

200

0 20 40 60 80 100 120Exp

irato

ry v

alve

Vt

Pneumotachometer Vt

R2 = 0.54

y = 1.06x + 29


020406080

100120140160

0 20 40 60 80 100 120

Effe

ctiv

e V

t

Pneumotachometer Vt

R2 = 0.58

y = 1.02x + 19

ConclusionConclusionCalculating delivered tidal volumes are not sufficient because of multiple uncontrolled variables: in-line suction catheters condensation secretions EtCO2 adapters humidifiers / heaters etc.

Calculating delivered tidal volumes are not sufficient because of multiple uncontrolled variables: in-line suction catheters condensation secretions EtCO2 adapters humidifiers / heaters etc.




Case series



Case series

Efficacy of delivered breathsEfficacy of delivered breaths

Mechanical ventilators are routinely set to deliver a minute ventilation based on ideal body weight and physiologic respiratory rate.

MVTOTAL = VT (6cc/kg) x RR (physiologic)

Mechanical ventilators are routinely set to deliver a minute ventilation based on ideal body weight and physiologic respiratory rate.

MVTOTAL = VT (6cc/kg) x RR (physiologic)

Effective VentilationEffective Ventilation

Many factors effect the ability of this delivered gas to actually reach the alveoli and participate in gas exchange

BronchospasmIncreased deadspace (VD)Decreased cardiac outputEtc………

Many factors effect the ability of this delivered gas to actually reach the alveoli and participate in gas exchange

BronchospasmIncreased deadspace (VD)Decreased cardiac outputEtc………

Effective VentilationEffective Ventilation

To determine the amount of gas that reaches the lungs and actually participates in gas exchange, it is important to determine the alveolar minute ventilation (MVALV).

To determine the amount of gas that reaches the lungs and actually participates in gas exchange, it is important to determine the alveolar minute ventilation (MVALV).

Alveolar Minute VentilationAlveolar Minute Ventilation

MVALV is calculated from a SBCO2 waveform which is continuously displayed when monitoring with volumetric capnography.

MVALV is calculated from a SBCO2 waveform which is continuously displayed when monitoring with volumetric capnography.E

xpir

ed C

O2

VT

MVALV Calculation from aSBCO2 Waveform

MVALV Calculation from aSBCO2 Waveform

ExhaledVolume

Volume CO2

Exp

ired

CO

2

EtCO2

ExhaledVolume

Volume CO2

Exp

ired

CO

2E

xpire

d C

O2

PaCO2PaCO2

EtCO2EtCO2

A line is drawn parallel to the alveolar phase of the EtCO2 waveform.

A 2nd line corresponding to PaCO2 is drawn.

A line is drawn parallel to the alveolar phase of the EtCO2 waveform.

A 2nd line corresponding to PaCO2 is drawn.

ExhaledVolume

Exp

ired

CO

2E

xpire

d C

O2

PaCO2PaCO2

EtCO2EtCO2

qq

pp

A 3A 3rdrd line is drawn perpendicular to the x line is drawn perpendicular to the x axis so that area q = area p.axis so that area q = area p.A 3A 3rdrd line is drawn perpendicular to the x line is drawn perpendicular to the x axis so that area q = area p.axis so that area q = area p.

ExhaledVolume

Exp

ired

CO

2E

xpire

d C

O2

PaCO2PaCO2

EtCO2EtCO2

qq

pp

X = alveolar ventilationY = alveolar dead spaceZ = airway dead space

MValv = ‘X’ x RR

XXZZ

YY

Clinical SignificanceClinical Significance

20 heterogeneous mechanically ventilated PICU pts (0-18 yrs)

Continuous volumetric capnography (NICO2 Respiratory Profile Monitor, Respironics / Novametrix, Inc. Wallingford CT)

Compared MVTOTAL to MVALV over a 24 hr period

20 heterogeneous mechanically ventilated PICU pts (0-18 yrs)

Continuous volumetric capnography (NICO2 Respiratory Profile Monitor, Respironics / Novametrix, Inc. Wallingford CT)

Compared MVTOTAL to MVALV over a 24 hr period

MVTOTAL vs. MVALVMVTOTAL vs. MVALV

45% (9/20) had an r2 < 0.7 20% (5/20) had an r2 < 0.5 1 pt demonstrated no correlation (r2 < 0.03) Additionally, linear regression ranged from

0.03 0.96 demonstrating that differences between MVTOTAL and MVALV are not consistent and, therefore, can not be predicted

45% (9/20) had an r2 < 0.7 20% (5/20) had an r2 < 0.5 1 pt demonstrated no correlation (r2 < 0.03) Additionally, linear regression ranged from

0.03 0.96 demonstrating that differences between MVTOTAL and MVALV are not consistent and, therefore, can not be predicted

pt # r2 data points pt # r2 data

points

1 0.96 1470 11 0.49 1442

2 0.81 1245 12 0.37 1298

3 0.89 1115 13 0.88 1467

4 0.42 1290 14 0.89 1462

5 0.93 1452 15 0.78 1443

6 0.91 1470 16 0.54 1461

7 0.31 1460 17 0.54 1463

8 0.69 1475 18 0.03 1463

9 0.80 1410 19 0.92 1443

10 0.58 1359 20 0.91 1432

MVTOTAL vs. MVALVMVTOTAL vs. MVALV

These data suggest continuous monitoring of MVALV provides a more accurate assessment of ventilator management strategies as well as the efficacy of delivered gas.



Clinical significance Tidal volume delivery Efficacy of delivered breaths Extubation success indicator Length of ventilation

Case series


Clinical significance Tidal volume delivery Efficacy of delivered breaths Extubation success indicator Length of ventilation

Case series

Extubation Criteria Extubation Criteria

Respiratory frequency to tidal volume ratio Yang, NEJM, 1991 Tahvanainen, CCM, 1983

T-piece trials Sahn, Chest, 1973

Negative insp effort measurements Sahn, Chest, 1973

CROP index (compliance, rate, oxygenation, pressure) Yang, NEJM, 1991

Numerous SBT studies

Respiratory frequency to tidal volume ratio Yang, NEJM, 1991 Tahvanainen, CCM, 1983

T-piece trials Sahn, Chest, 1973

Negative insp effort measurements Sahn, Chest, 1973

CROP index (compliance, rate, oxygenation, pressure) Yang, NEJM, 1991

Numerous SBT studies

Adult Patients

What about infants and children? What about infants and children?

There are no widely accepted criteria for predicting successful extubation in the pediatric population.

There are no widely accepted criteria for predicting successful extubation in the pediatric population.

Conventional Approaches Conventional Approaches

Clinical evaluation Physical exam Patient work of breathing Chest radiography Weight change from baseline Minimal ventilator settings Blood gas analysis

Clinical evaluation Physical exam Patient work of breathing Chest radiography Weight change from baseline Minimal ventilator settings Blood gas analysis

The use of VD/VT measurements to determine extubation readiness

The use of VD/VT measurements to determine extubation readiness The purpose of this study was to identify a The purpose of this study was to identify a

minimal physiological deadspace (Vd/Vt) minimal physiological deadspace (Vd/Vt) value using single breath carbon dioxide value using single breath carbon dioxide capnography for predicting successful capnography for predicting successful extubation from mechanical ventilation in extubation from mechanical ventilation in pediatric patients.pediatric patients.

The purpose of this study was to identify a The purpose of this study was to identify a minimal physiological deadspace (Vd/Vt) minimal physiological deadspace (Vd/Vt) value using single breath carbon dioxide value using single breath carbon dioxide capnography for predicting successful capnography for predicting successful extubation from mechanical ventilation in extubation from mechanical ventilation in pediatric patients.pediatric patients.

Hubble, CCM, 2000

Extubation Readiness: MethodsExtubation Readiness: Methods

Ventilation PS set to deliver Vt of 6 ml / kg PEEP & FiO2 not altered for study

20 minute equilibration Vd/Vt calculated Extubation Clinical team blinded to Vd/Vt ratio

Ventilation PS set to deliver Vt of 6 ml / kg PEEP & FiO2 not altered for study

20 minute equilibration Vd/Vt calculated Extubation Clinical team blinded to Vd/Vt ratio

Results:Individual Outcomes

Results:Individual Outcomes

**

##

p < 0.001

0.10 - 0.50 24 / 25 (96%) N IV (1)

0.51 - 0.64 6 / 9 (67%) N IV (3)

0.65 - 0.95 2 / 10 (20%) N IV (6), PPV (2)

0.10 - 0.50 24 / 25 (96%) N IV (1)

0.51 - 0.64 6 / 9 (67%) N IV (3)

0.65 - 0.95 2 / 10 (20%) N IV (6), PPV (2)

Vd/Vt Successful Extubation

Failed Extubation

Hubble, CCM, 2000

VD/VT: ResultsVD/VT: Results

0.10 – 0.50 very predictive of success 0.51 – 0.64 moderately predictive 0.65 – 0.95 very predictive of failure

0.10 – 0.50 very predictive of success 0.51 – 0.64 moderately predictive 0.65 – 0.95 very predictive of failure




Case series



Case series

Effects on length of ventilationEffects on length of ventilation

Does continuous monitoring of volumetric capnography with single breath CO2 technology decrease length of ventilation?

Does continuous monitoring of volumetric capnography with single breath CO2 technology decrease length of ventilation?

Randomized, non-blinded, prospective trial

Randomized, non-blinded, prospective trial

Intervention group Continuously monitored with volumetric

capnography (NICO2 Monitor Respironics Inc.) at initiation of CMV in PICU

Control group standard care including intermittent use of

advanced resp mechanics at the discretion of the pt care team

Intervention group Continuously monitored with volumetric

capnography (NICO2 Monitor Respironics Inc.) at initiation of CMV in PICU

Control group standard care including intermittent use of

advanced resp mechanics at the discretion of the pt care team

Hamel et al, 2005Hamel et al, 2005

Study CriteriaStudy Criteria Inclusion criteria

all ventilated patients ≤ 18 yrs Exclusion criteria

none

Inclusion criteria all ventilated patients ≤ 18 yrs

Exclusion criteria none

Outcome VariablesOutcome Variables

Primary endpoint length of ventilation

Secondary endpoints # of CXRs and ABGs complication rate

Primary endpoint length of ventilation

Secondary endpoints # of CXRs and ABGs complication rate

Preliminary ResultsPreliminary Results

NICO2 group (n = 104)

LOV = 117.3 Control group (n = 103)

LOV = 171.4 Statistical analysis: p = 0.002 Clinical analysis:

LOV ↓ by 54 hrs (2.25 days) 32% decrease

NICO2 group (n = 104)

LOV = 117.3 Control group (n = 103)

LOV = 171.4 Statistical analysis: p = 0.002 Clinical analysis:

LOV ↓ by 54 hrs (2.25 days) 32% decrease

Hamel et al, 2005

Preliminary ConclusionsPreliminary Conclusions

Continuous monitoring of volumetric capnography decreases length of ventilation in a heterogeneous group of infants and children. Accurate tidal volume determination VCO2

MVALV

VD/VT

Continuous monitoring of volumetric capnography decreases length of ventilation in a heterogeneous group of infants and children. Accurate tidal volume determination VCO2

MVALV

VD/VT

Hamel et al, 2003




Case series



Case series

Case: 1Case: 1

15 month 10 kg little boy History of prematurity (former 26 wk) Presents in ED in respiratory failure Orally intubated Transferred to PICU

15 month 10 kg little boy History of prematurity (former 26 wk) Presents in ED in respiratory failure Orally intubated Transferred to PICU

Mechanical ventilationMechanical ventilation

Servo 300 ventilator SIMV volume limited FiO2 0.50 RR 22 bpm Vt set 75 mL PEEP + 5 cm H2O PSV +10 cm H2O

Servo 300 ventilator SIMV volume limited FiO2 0.50 RR 22 bpm Vt set 75 mL PEEP + 5 cm H2O PSV +10 cm H2O

Patient parametersPatient parameters

Arterial blood gas pH 7.37 PaCO2 56 torr

PaO2 113 torr

Placed on NICO2 Respiratory Profile Monitor

VCO2 64 mL/min

SaO2 95%

Arterial blood gas pH 7.37 PaCO2 56 torr

PaO2 113 torr

Placed on NICO2 Respiratory Profile Monitor

VCO2 64 mL/min

SaO2 95%

Patient conditionPatient condition

Increased work of breathing RR 36 Retractions Appearance of ‘discomfort’

Bilateral wheezes Decreased oxygen saturation (88%)

Increased work of breathing RR 36 Retractions Appearance of ‘discomfort’

Bilateral wheezes Decreased oxygen saturation (88%)

ResponseResponse

Bronchodilator tx given PEEP was from 5 to 8 cmH2O SaO2 ↑ to 95% However…….

Bronchodilator tx given PEEP was from 5 to 8 cmH2O SaO2 ↑ to 95% However…….

VCO2 rapidly decreasedVCO2 rapidly decreased

Inspection of SBCO2 waveform showed ↑in phase 1: indicative of ↑ VDANA

↓in phase 2: indicative of ↓ perfusion

Inspection of SBCO2 waveform showed ↑in phase 1: indicative of ↑ VDANA

↓in phase 2: indicative of ↓ perfusion

0

10

20

30

40

0 10 20 30 40 50

Expired Tidal Volume (ml)

ET

CO

2 (m

mH

g)

Phase I Phase II Phase III

VCO2

↑Phase 1: ↑VDANA↑Phase 1: ↑VDANA

↑ airway obstructionPatient has RAD? Give another bronchodilator treatment

Excessive PEEPRecent ↑ PEEP? Decrease PEEP level

↑ airway obstructionPatient has RAD? Give another bronchodilator treatment

Excessive PEEPRecent ↑ PEEP? Decrease PEEP level

↓ Phase 2: ↓perfusion↓ Phase 2: ↓perfusion ↓ venous return

Fluid related? Ventilator related? Excessive PEEP?

↑ intrathoracic pressure Is it ventilator related? Excessive PEEP?

↓ venous return Fluid related? Ventilator related? Excessive PEEP?

↑ intrathoracic pressure Is it ventilator related? Excessive PEEP?

Our patientOur patient

Changes in both phase 1 & 2 of SBCO2 waveform

Phase 1 No worsening RAD PEEP was just increased

Phase 2 Fluid status unchanged PEEP was just increased

Changes in both phase 1 & 2 of SBCO2 waveform

Phase 1 No worsening RAD PEEP was just increased

Phase 2 Fluid status unchanged PEEP was just increased

Based on SBCO2 findingsBased on SBCO2 findings

No additional bronchodilator tx given No additional vascular volume given PEEP was ↓ to 6 cmH2O SaO2 remained 95%

No additional bronchodilator tx given No additional vascular volume given PEEP was ↓ to 6 cmH2O SaO2 remained 95%

Day 3: weaningDay 3: weaning

(S)IMV rate ↓5bpm Patient began taking over ventilation After 1 hour VCO2 ↓dramatically

No visible signs of fatigue No changes in ETCO2

No changes in SBCO2 waveform

(S)IMV rate ↓5bpm Patient began taking over ventilation After 1 hour VCO2 ↓dramatically

No visible signs of fatigue No changes in ETCO2

No changes in SBCO2 waveform

Now what?Now what?

Look for trends in bar graph MV stable? Are spon. volumes stable?

Look for trends in bar graph MV stable? Are spon. volumes stable?

What does that mean?What does that mean?

A ↓ in VCO2 followed by a ↓in VTSPON

indicative of weaning failure If continued will lead to in PaCO2 & EtCO2

IMV ↑ to 14 bpm

A ↓ in VCO2 followed by a ↓in VTSPON

indicative of weaning failure If continued will lead to in PaCO2 & EtCO2

IMV ↑ to 14 bpm

Next dayNext day

↑ spontaneous effort VCO2 ↑ suggesting ’d metabolic activity due to

additional task of breathing Delivered mechanical VT had not been

changed & spontaneous VT is increasing ↓IMV to 5bpm

↑ spontaneous effort VCO2 ↑ suggesting ’d metabolic activity due to

additional task of breathing Delivered mechanical VT had not been

changed & spontaneous VT is increasing ↓IMV to 5bpm

Successful weaningSuccessful weaning

OutcomeOutcome After 93 hours of mechanical ventilation, the

patient was successfully extubated. Continuous monitoring of VCO2 allowed for

rapid response to this patient’s changing ventilatory needs.

After 93 hours of mechanical ventilation, the patient was successfully extubated.

Continuous monitoring of VCO2 allowed for rapid response to this patient’s changing ventilatory needs.

Case: 2Case: 2 6 month 5.2 kg White female PICU S/P B-T shunt (HLHS) Orally intubated with 3.5 uncuffed ETT

6 month 5.2 kg White female PICU S/P B-T shunt (HLHS) Orally intubated with 3.5 uncuffed ETT

Patient parametersPatient parameters Minimal ventilator settings

VSV, FiO2 = 0.40, VTSET = 40cc, RRset 22 bpm, PEEP + 5 cm H2O, TI 0.5

Patient parameters SaO2 - 70s ETCO2 - 34 VCO2 - 32

BP - 80/36 HR - 150 bpm

Minimal ventilator settings VSV, FiO2 = 0.40, VTSET = 40cc, RRset 22 bpm,

PEEP + 5 cm H2O, TI 0.5 Patient parameters

SaO2 - 70s ETCO2 - 34 VCO2 - 32

BP - 80/36 HR - 150 bpm

Case progressionCase progression SaO2 decreased to 58% BP 80/36 HR 150 bpm ETCO2 34

essentially unchanged VCO2 16

SaO2 decreased to 58% BP 80/36 HR 150 bpm ETCO2 34

essentially unchanged VCO2 16

Initial ResponseInitial Response Adjusted ventilator settings

VSV SIMV / 40 / 14Increase FiO2

No response to ventilator management strategies

Patient returned to VSV

Adjusted ventilator settingsVSV SIMV / 40 / 14Increase FiO2

No response to ventilator management strategies

Patient returned to VSV

AssessmentAssessment Noted that VCO2 had previously been in

the high 20’s

Noted that VCO2 had previously been in the high 20’s

1631591:50

1633591:49

1735701:48

1634741:47

1637731:46

1836751:45

3237751:44

VCO2ETCO2SpO2TIME

AssessmentAssessment

SBCO2 showed ↓in phase 2 MV unchanged No ↑ PEEP

SBCO2 showed ↓in phase 2 MV unchanged No ↑ PEEP

Decreased Perfusion

Baseline

ResponseResponse During preparation to administer volume

BP 50/28 HR 164 bpm

10cc’s / kg of volume administered SaO2 stabilized HR returned to baseline trend BP returned to baseline

During preparation to administer volume BP 50/28 HR 164 bpm

10cc’s / kg of volume administered SaO2 stabilized HR returned to baseline trend BP returned to baseline

Case Study: 2Case Study: 2

VCO2 responded to change in perfusion 5 minutes before SaO2, and even longer before ETCO2, HR, BP changed!

VCO2 responded to change in perfusion 5 minutes before SaO2, and even longer before ETCO2, HR, BP changed!

SummarySummary

Five minutes can be very significant in a hemodynamically unstable child.

Had this patient been in a more acute phase of her convalescence her outcome could have been very different.

Five minutes can be very significant in a hemodynamically unstable child.

Had this patient been in a more acute phase of her convalescence her outcome could have been very different.

Case: 3Case: 3

12 year female Previously healthy Presents at ED with

SOB Tachypneic (RR = 22) Mild hypoxia (SaO2 = 90% on RA)

12 year female Previously healthy Presents at ED with

SOB Tachypneic (RR = 22) Mild hypoxia (SaO2 = 90% on RA)

ED treatmentED treatment

2 LPM nasal cannula Bronchodilator administered Improved SaO2 (98%) Discharged to home

Albuteral MDI PRN F/U with primary care physician on Monday

2 LPM nasal cannula Bronchodilator administered Improved SaO2 (98%) Discharged to home

Albuteral MDI PRN F/U with primary care physician on Monday

Physician follow upPhysician follow up

Diagnosed new onset RAD Asthma treatment plan initiated

Flovent daily Peak flow daily Yellow zone – Albuterol Yellow zone x 3 requires Dr. visit Red zone – albuterol tx & immediate ED

visit

Diagnosed new onset RAD Asthma treatment plan initiated

Flovent daily Peak flow daily Yellow zone – Albuterol Yellow zone x 3 requires Dr. visit Red zone – albuterol tx & immediate ED

visit

Next two weeksNext two weeks

4 ED visits 4th visit via ambulance Admitted to a tertiary non-academic

medical center Diagnosis – status asthmaticus * Significant weight loss

4 ED visits 4th visit via ambulance Admitted to a tertiary non-academic

medical center Diagnosis – status asthmaticus * Significant weight loss

Case progressionCase progression

Continuous albuterol O2 therapy Worsening condition Intubated Transferred to Duke PICU

Continuous albuterol O2 therapy Worsening condition Intubated Transferred to Duke PICU

Duke: Day 1Duke: Day 1 Continuous albuterol Artrovent Q6 IV steroids (S)PRVC

FiO2 0.70 VT 7 ml/kg RR 18 PEEP 5 cmH2O PIP 30 cmH2O

Continuous albuterol Artrovent Q6 IV steroids (S)PRVC

FiO2 0.70 VT 7 ml/kg RR 18 PEEP 5 cmH2O PIP 30 cmH2O

Patient assessmentPatient assessment ABG

7.26, PaCO2 56, PaO2 50 SaO2 89% HR & BP WNL VCO2 - 245

ABG 7.26, PaCO2 56, PaO2 50

SaO2 89% HR & BP WNL VCO2 - 245

Case progressionCase progression Worsening clinical status

PaCO2 ↑ VCO2

Assessment of SBCO2 waveform Slight ↑ phase 1 Significant ↑ phase 3

Worsening clinical status PaCO2 ↑ VCO2

Assessment of SBCO2 waveform Slight ↑ phase 1 Significant ↑ phase 3

SBCO2SBCO2

Increased phase 1 & 3Increased phase 1 & 3

Phase 1 - VDANA

Excessive PEEP ↑ airway obstruction

Phase 3 – gas distribution ↑ V/Q mismatch ? Excessive PEEP ↑ airway obstruction

Phase 1 - VDANA

Excessive PEEP ↑ airway obstruction

Phase 3 – gas distribution ↑ V/Q mismatch ? Excessive PEEP ↑ airway obstruction

AssessmentAssessment

PEEP Mild PEEPi present indicative of airway

obstruction PEEP titrated to meet PEEPi level

Airway obstruction Bronchodilator therapy already maximized Added Heliox

PEEP Mild PEEPi present indicative of airway

obstruction PEEP titrated to meet PEEPi level

Airway obstruction Bronchodilator therapy already maximized Added Heliox

PICU day 4PICU day 4

Continued worsening of condition pH at threshold PaCO2 severely elevated Oxygenation (already impaired) unchanged VCO2 continued to

Bronchoscopy Non-diagnostic Cultures sent

Continued worsening of condition pH at threshold PaCO2 severely elevated Oxygenation (already impaired) unchanged VCO2 continued to

Bronchoscopy Non-diagnostic Cultures sent

PICU day 5: New informationPICU day 5: New information

1 month prior to admission Visited zoo Visited the aviary where inhaled ???

substance which led to spasmodic coughing episode.

Laboratory cultures sent for differential diagnosis

1 month prior to admission Visited zoo Visited the aviary where inhaled ???

substance which led to spasmodic coughing episode.

Laboratory cultures sent for differential diagnosis

New diagnosisNew diagnosis

Laboratory cultures positive for histoplasma capsulatum Symptoms occur 5-18 days post exposure RAD like symptoms occurred 2 weeks

following zoo visit. Anti-fungals started

Laboratory cultures positive for histoplasma capsulatum Symptoms occur 5-18 days post exposure RAD like symptoms occurred 2 weeks

following zoo visit. Anti-fungals started

OutcomeOutcome

Histoplasmosis had disseminated Family offered lung transplant Declined due to poor prognosis She was extubated and able to return

home where she did succumb to her disease.

Histoplasmosis had disseminated Family offered lung transplant Declined due to poor prognosis She was extubated and able to return

home where she did succumb to her disease.

SummarySummary

While monitoring with volumetric capnography did not change the final outcome, it did provide information valuable in optimizing her support.

She was able to be extubated and return home to her family.

While monitoring with volumetric capnography did not change the final outcome, it did provide information valuable in optimizing her support.

She was able to be extubated and return home to her family.

Case: 4Case: 4

2 m/o male Vaters syndrome

Vertebral anomalies TE fistula Renal anomalies Limb anomalies

2 m/o male Vaters syndrome

Vertebral anomalies TE fistula Renal anomalies Limb anomalies

Of concernOf concern

Trachea Deviated 300 angle to right Sporadic areas of narrowing Fixed obstruction

Hypoplastic left lung 2 subcutaneous soft tissue masses in

the chest (L>R)

Trachea Deviated 300 angle to right Sporadic areas of narrowing Fixed obstruction

Hypoplastic left lung 2 subcutaneous soft tissue masses in

the chest (L>R)

Chest CTChest CT

Airway issuesAirway issues

Trached Anomalous airway structure Fixed obstructions & restrictions Metal trach due to occlusion issues with

standard trachs Mechanically ventilated

Pressure limited (S)IMV, VT 6 cc/kg, PEEP 8, RR 16, FiO2 0.40

Heliox 60/40 To assist in gas delivery

Trached Anomalous airway structure Fixed obstructions & restrictions Metal trach due to occlusion issues with

standard trachs Mechanically ventilated

Pressure limited (S)IMV, VT 6 cc/kg, PEEP 8, RR 16, FiO2 0.40

Heliox 60/40 To assist in gas delivery

Patient parametersPatient parameters

ABG 7.26, 50, 80, 87%

VCO2 – 40 ml/min HR & BP WNL Urine output -

ABG 7.26, 50, 80, 87%

VCO2 – 40 ml/min HR & BP WNL Urine output -


Pt. asleep SaO2 stable HR & BP stable Urine output continuing to

Pt. asleep SaO2 stable HR & BP stable Urine output continuing to


VCO2 20 Within minutes VT to 3 cc/kg Followed by SaO2 – 50s

VCO2 20 Within minutes VT to 3 cc/kg Followed by SaO2 – 50s

ConsiderationsConsiderations

Fluid overload? Renal insufficiency present

Inadequate PEEP Not meeting critical opening pressure

hence in VT delivery

Fluid overload? Renal insufficiency present

Inadequate PEEP Not meeting critical opening pressure

hence in VT delivery

SBCO2 waveformSBCO2 waveform

No significant changes in slopes of any phases

No significant changes in slopes of any phases

What does that tell us?What does that tell us?

No changes in phase 1slope PEEP not excessive No ↑ in obstruction

No changes in phase 2 slope No evidence of fluid overload (would most

likely result in phase 2) No changes in phase 3 slope

Inadequate PEEP ruled out (would most likely result in ↑ mal distribution of gas)

No changes in phase 1slope PEEP not excessive No ↑ in obstruction

No changes in phase 2 slope No evidence of fluid overload (would most

likely result in phase 2) No changes in phase 3 slope

Inadequate PEEP ruled out (would most likely result in ↑ mal distribution of gas)

What should we do?What should we do?

↑ FiO2? Remember this patient is dependent on

heliox for gas delivery Why in VT?

Is patient awakening? Is patient fatigued?

↑ FiO2? Remember this patient is dependent on

heliox for gas delivery Why in VT?

Is patient awakening? Is patient fatigued?

Look at trending barLook at trending bar

Is VE stable? Are spontaneous efforts increased?

Is VE stable? Are spontaneous efforts increased?

Our patientOur patient

Bar graphs indicated fatigue Patient began waking When taking over ventilation, pt tired

almost immediately!

Bar graphs indicated fatigue Patient began waking When taking over ventilation, pt tired

almost immediately!

Our responseOur response

Patient not ready to take over ventilation No ventilator changes made No change in diuretics Patient sedated

Patient not ready to take over ventilation No ventilator changes made No change in diuretics Patient sedated

SummarySummary

With the information provided with volumetric capnography we were able to respond quickly to this pt’s ventilatory needs.

Were able to rule out the need to ↑ ventilatory support.

We ruled out need for additional diuretics. We could treat the pt with objective data.

With the information provided with volumetric capnography we were able to respond quickly to this pt’s ventilatory needs.

Were able to rule out the need to ↑ ventilatory support.

We ruled out need for additional diuretics. We could treat the pt with objective data.

What did we learn? What did we learn? We do not know if volumetric capnography

really changed this pt’s course. We do know is that we did not ‘over’ treat

him. We do know that without this data, this pt

would most likely have had more ventilatory & renal support than needed.

We do not know if volumetric capnography really changed this pt’s course.

We do know is that we did not ‘over’ treat him.

We do know that without this data, this pt would most likely have had more ventilatory & renal support than needed.

When provided with the right information…

When provided with the right information…

we may spend less time doing the wrong thing!we may spend less time doing the wrong thing!

ConclusionConclusion

Monitoring with volumetric capnography will most likely not change clinical practice.

What it will do is provide information that will enhance clinical practice.

Management strategies can be based on objective data.

Monitoring with volumetric capnography will most likely not change clinical practice.

What it will do is provide information that will enhance clinical practice.

Management strategies can be based on objective data.

Thank you!Thank you!

the use of volumetric capnography in the management of ...the

Documents

vt phase

alveolar ventilation

phases of sbco2 waveform

tidal volume determination

transitional phase

large airway ventilation

sbco2 waveform expiredco2

expiratory vt