19 introduction of volumetric capnography

“Introduction of Volumetric Capnography

One Hospital’s Experience”

Presented By: Michael Powers, MS, RRT

Director, Lung CenterUniversity of Tennessee Medical Center

Knoxville, Tennessee

Agenda:

VCO2 ManagementClinical ApplicationsUniversity of Tennessee Medical Center’s

Experience and DataOther Hospital’s Outcome Data

VCO2 Management

1. Why to use

2. How to use

Monitoring CO2 Elimination • VCO2 provides continuous feedback regarding

ventilation and perfusion Relationship between PaCO2 and VCO2 is

inverse and consistent Instant feedback when making ventilator

setting changes:• Did perfusion change?• Did ventilation change?• With PaCO2 from an ABG, you can answer the

question, “Did Vd/Vt change?”

Metabolism(CO2 Production)

CO2 Elimination(VCO2)

PaCO2

VCO2 - A Few Basics

Things that affectCO2 elimination

Circulation

Diffusion

Ventilation

1 2

CO2 Elimination(VCO2)

Why Measure VCO2?

Very Sensitive Indicator of

PATIENT STATUS CHANGE Early Indicator Future Changes in

PaCO2

Another Tool to Assist in

Determining When to Draw a Blood

Gas Reduces the # of ABGs

VCO2 - A Few Basics

3

Volumetric Capnography

Integration of Flow & CO2

The integration of CO2 and Flow provides an easy method to obtain previously difficult to obtain parameters VCO2 = CO2 Elimination Airway Deadspace, Physiologic VD/VT Alveolar Ventilation Cardiac Output

Integration of Flow & CO2

EtCO2 CapnogramRespiratory Rate

Capnography Volumetric CO2

CO2 EliminationAirway DeadspaceAlveolar VentilationPhysiologic Vd/Vt

Phase I – Airway Gas

The waveform is divided into three phases:The waveform begins at the onset of expiration. Imagine that you are the sensor sitting in the proximal airway. The first gas past the sensor at onset of expiration does not contain any CO2 but does have volume. The graph shows movement along the X-axis (exhaled volume) but no gain in CO2 (Y-axis).

This volume is entirely from the conducting airways - no gas exchange has taken place.

Phase I represents pure airway gas.

Phase II – Transitional Gas

Phase II represents gas that is composed partially of airway volume and partially from early emptying alveoli (fast time constant).

At about generation 17 of the airway tree we find alveolar units that communicate directly with the conducting airway and are considered fast time constant units.

It is considered transitional gas (from airway to alveoli). An assumption is made here:50% of phase II gas belongs to the airway and 50% belongs to the alveoli. Further research is needed to determine if this holds true in all clinical conditions (such as dramatically increasing PEEP).

Phase III – Alveolar Gas

Phase III gas is entirely from the alveolar bed where gas exchange takes place.

Single Breath CO2 Waveform

EtCO2

Exhaled Tidal Volume

VD VALV

Z

Y

X

Clinical Application

Ventilation Management

Customize ventilator settings: VCO2 (CO2 elimination) reflects any changes in ventilation

and/or perfusion; it indicates instantly how patient gas exchange responds to ventilator

setting changes

Customize ventilator settings: VCO2 (CO2 elimination) reflects any changes in ventilation

and/or perfusion; it indicates instantly how patient gas exchange responds to ventilator

setting changes

VCO2

Vd/Vt

MValv

“Noninvasively monitored VCO2 provides an instantaneous indication of the change in alveolar ventilation in mechanically ventilated patients. It

allows instant, cheap and noninvasive determination of effective gas exchange.”

Dynamics of Carbon Dioxide Elimination Following Ventilator Resetting. Varsha Taskar, MD ; Joseph John, MD ; Anders Larsson, MD,PhD ; Torbjörn Wetterberg, MD, PhD ; Björn Jonson, MD, PhD – Chest 108/1/July 1995

.

.

Vd/Vt

• Ratio of Total Deadspace (Vd or Vdphys) to Tidal

Volume (Vt)• Total Deadspace = Airway + Alveolar Deadspace

• Normal = 0.25 to 0.30

• Estimates the Overall (In)efficiency of the

CardioRespiratory System

Why Measure Vd/Vt ? • Helps Understand what is Happening at the Alveolar Capillary Interface

• Measures Effectiveness of Ventilation

• Get Baseline Vd/Vt Defines Severity of Insult

Decrease in Perfusion

Baseline Perfusion

Decreased Perfusion

Monitoring trends allows for detection of sudden and rapid in VCO2, without change in Alveolar Minute Volume or Tidal Volumes. Drop in VCO2 suggests change in blood flow to the lungs. VCO2 may be due to in C.O. or blood loss. VCO2 may be due to in C.O. or malignant hyperthermia. Coupled with Alveolar Ventilation and Deadspace measurements, this allows for quick patient assessment.

Monitoring trend screens

Optimization of PEEP using VCO2/NICO

CASE STUDY:Profile: 60 Yr. Male, History of COPD and cardiac problems, Admitted to ED with severe respiratory distress, elevated temperature and semi-comatose. Patient intubated and placed on control ventilation and monitored with NICO. Tidal Volume (6ml/kg)= 600 ml, Respiratory Rate=10, I:E=1:2, PEEP= 8 FiO2 = 40%.

Baseline CO = 4 L/min, Over time SpO2 decreases from 94 to 88%. Flow/Volume loop and capnogram exhibit severe airway obstruction and increased work of breathing. Bronchodilator treatment administered and PEEP increased to 15 CmH2O. SpO2 = 95%. Observed a decrease in VCO2 (150 mL/m) and CO (2.5 L/m) due to increased intrathoracic pressure and decreased venous return. PEEP reduced to 8 cmH2O. Both cardiac output (3.4 L/m) and VCO2 (225 mL/m) returns to baseline levels.

Discussion: Use of NICO provided immediate and continuous feedback on the appropriateness of the ventilator strategy, and also allowed expeditious optimization of cardiac performance.

PEEP=0 PEEP lowered to 4

cmH2OPEEP

increased to 8 cmH2O

Alveolar Ventilation

MValv

• Alveolar Ventilation per Minute

• Amount of Vt that Reaches the Alveoli and is Available for Gas Exchange (Effective Ventilation)

Why Measure MValv ?

To provides the Most Effective CO2 Removal

To manage alveolar ventilation and not Vt

Successful Weaning Trial

Shows in spontaneous alveolar ventilation & corresponding decrease in ventilator support. VCO2 suggests metabolic activity due to additional task of breathing by the patient. Delivered mechanical tidal volume has not changed & spontaneous tidal volume is increasing (SIMV rate ). Shows PATIENT RESPONSE to the trial allowing for better management of the weaning process.

Unsuccessful Weaning Trial

SIMV and patient started to take over ventilation. But patient shows signs of fatigue at early stage ( VCO2 followed by in spontaneous tidal volume). Leads to in PaCO2 & EtCO2. Return to mechanical ventilation. Assists clinicians in determining PATIENT RESPONSE. When used effectively, these utilities may help reduce costly ventilator days.

Successful SBT

Here the patient’s ability to maintain Alveolar Ventilation sufficient for CO2 removal during a T-Piece Trial is proven.

Spontaneous Tidal Volumes have remained constant and have even shown slight increases over time.

Trends also show that the patient has been off mechanical support throughout the trial (no Vte MECH trend bars).

Unsuccessful SBT Initially, patient had a small amount of ventilatory support, but then was placed on a T-piece. The entire task of breathing was placed on the patient. Within minutes trends showed that the patient was unable to support the required level of ventilation (VCO2 decreasing since total Alveolar Ventilation is decreasing). Spontaneous Tidal Volume trend also shows inadequate ventilation. Removal of mechanical support, increased Vd/Vt, reducing ventilatory efficiency and the patient’s ability to remove CO2. This resulted in a pattern of rapid shallow breaths requiring the patient to be placed back on full mechanical support.

University of Tennessee Medical Center Data

• 600 Bed Hospital

• Designated Level 1 Trauma Center for Adults and Pediatrics

• Associated with University of Tennessee Graduate School of Medicine

• 50+ Bed Level 3 NICU

• 70+ Bed Adult Critical Care

• Operate Aggressive Therapist Driven Protocols on All Modalities of RC

Hospital Constraints

Step Down Units created (sub-acute care)

Step Down Units created (sub-acute care)

More severe ICU patient population

More severe ICU patient population

PreferNoninvasive technologies

PreferNoninvasive technologies

Pressure on hospital budgets

Human resources limited

Pressure on hospital budgets

Human resources limited

Need to keep ventilator-

time as minimal as

possible

Need to keep ventilator-

time as minimal as

possible

Need to be efficient and costsNeed to be efficient and costs

University of TN Medical Center

Implementation of Ventilation Management Protocol

3.3

12.5

2.0

11.0

0

5

10

15

VLOS HLOS

Pre-Protocol (585 pts)

Post-Protocol (643 pts)

Decrease of 39% Decrease of 12%

Re-intubation Rates

Extubation/Reintubation Rates

97939395

0

20

40

60

80

100

120

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

% N

ot

Re-

intu

bat

ed

Extubation/Reintubation Goal *Less than 6%

Quickly specific patient population became clear…

Patients in ALI/ARDS: requiring monitoring for optimization of PEEP and other ventilator settings

Patients with ventilator dysynchrony or other respiratory pattern issues that require differentiation of etiologies, prevention of exhaustive failures, etc.– Patients with failures to get to SBT, or appearances

of failures, such as RSBI, GCS, etc.– Differentiating Tachypnea vs Dyspnea– Early detection of exhaustion prior to

signs/symptoms

University of TN Medical Center

Difficult to Wean Patients(Five Months Retrospective)

30.7

1712

24.7

0

10

20

30

40

VLOS HLOS

Pre NICO (43 pts)

Post NICO (25 pts)

Decrease of 29% Decrease of 20%

Comparison Data

Reduction of Mechanical Ventilation Hours Using a Working Protocol with

the Cardiopulmonary Management System

Mikel W. O'Klock RRT, Dennis Harker RRT, Aksay Mahadevia MD, FCCP

Genesis Medical Center, Davenport, IA.

Reference: Respiratory Care, Dec 2005, Vol 50, Number 12, Page 95

Genesis Medical Center, Davenport, IA.

Background: Genesis Medical Center (GMC) is a 500 bed hospitalwith three adult Intensive Care units (ICUs) totaling45 lCU beds. Mechanical Ventilation Hours (MVH)for fiscal year 2003 totaled 84,000 with an average of123 hours per patient. We adopted a MechanicalVentilation Management Strategy Protocolincorporating the Respironics CardiopulmonaryManagement System (NICO) in an attempt to effectively reduce MVH.

Genesis Medical Center (cont).

Methods:

We retrospectively measured our MVH for

2003-2004. Next a protocol was

implemented using data from the NICO

monitor (SBCO2, VCO2, EtCO2, CO and

Vd/Vt) and a decision template. After 12

months of managing patients using the

protocol, MVH were again measured.

Genesis Medical Center (cont).

Results:By incorporating the ventilation management protocol, the decision process was simplified for both physician and therapist. This resulted in a significant reduction (p=0.001) in mechanical ventilation hours per patient.Ventilator Hours Statistical Analysis

Year Number of Patients

Total MVH MVH/pt

2003 612 72,492 118

2004 598 41,144 69

Genesis Medical Center (cont).

Conclusion:

By implementing a care protocol

incorporating the Respironics NICO we

observed a decrease of 43.2% in the total

number of ventilator hours, and a 42%

decrease in the number of hours per patient.

Genesis Medical Center (cont).

Implementation of Care Protocol Incorporating NICO

Total MVH

72,492

41,144

10,000

30,000

50,000

70,000

90,000

2003 (612 pts) 2004 (598 pts)

Decrease of 42.2%

Pre-NICO Post-NICO

Genesis Medical Center (cont).

Implementation of Care Protocol Incorporating NICO

(MVH per Patient)

118

69

0

50

100

150

2003 (612 pts) 2004 (598 pts)

Decrease of 42%

Pre-NICO Post-NICO

Genesis Medical Center (cont).

Continuous Monitoring Of Volumetric Capnography Reduces Length Of Mechanical Ventilation In A Heterogeneous Group Of Pediatric ICU Patients

Donna Hamel,RRT, RCP,FAARC Ira Cheifetz, MD, FAARC; Pediatric Critical Care Medicine.

Duke Children's Hospital, Durham, North Carolina

Reference: Respiratory Care, Dec 2005, Vol 50, Number 12, Page 107

Duke Children's Hospital, Durham, North Carolina

Background: Complications result from mechanical ventilation evenunder the best of circumstances; therefore, careful consideration must be provided for optimal management strategies on a continual basis. Recentadvances in technology provide clinicians access tononinvasive monitoring devices with the ability to display measurable and consistent data, thus, allowing for a more objective approach to totalventilator management.

Duke Children's Hospital (cont).

Volumetric capnography displays breath-by-breathmeasurements of exhaled carbon dioxide during the entire respiratory cycle. Additionally, theintegration of flow and carbon dioxide elimination over time enables the capnograph to calculate anddisplay alveolar minute ventilation (MVALV) anddeadspace ventilation (Vd/Vt). Therefore, volumetriccapnography should be a better marker for monitoring dynamic changes in gas exchange during mechanical ventilation than standard time-based capnometry alone.

Duke Children's Hospital (cont).

Hypothesis:

We hypothesized that the management of

patients using continuous volumetric capnography,

including monitoring of the deadspace to tidal

volume ratio, alveolar minute ventilation, and carbon

dioxide elimination (VCO2) would reduce the length

of ventilation (LOV) in infants and children.

Duke Children's Hospital (cont).

Methods: All mechanically ventilated PICU patients (0-18years of age) were eligible for enrollment in thisprospective, randomized study. Interventionpatients were placed on a NICO Respiratory Profile Monitor (Respironics, Inc.) on initiation of mechanicalventilation in our Pediatric lCU. These patients remained on the NICO Monitor until extubation. Control patients received all standard care and monitoring including intermittent use of volumetriccapnography at the discretion of the PICU team.

Duke Children's Hospital (cont).

Results:Both the parametric t-test and the non-parametric Wilcoxon test reflect a statistically significant difference in average length of ventilation with LOVbeing significantly reduced for the NICO group. Patients managed with continuous volumetric capnography (n=99) had a significantly shorter LOV than control patients (n=99) (117.3 vs. 171.4 hrs; P = 0.002). Extubation failure rates were similar for both groups.

Duke Children's Hospital (cont).

Conclusion:Length of ventilation in a heterogeneous group of pediatric patients was decreased by 2.25 days, a clinically significant 32%, with the use of Vd/Vt, MVALV and VCO2 monitoring. Such a significant decrease in LOV should corre late with a reductionin length of lCU admission cost, complications andmorbidity as well as improved patient and family satisfaction.

Duke Children's Hospital (cont).

Length of Ventilator Hours (99 patients)

171.4

117.3

0

50

100

150

200

Pre NICO Post NICO

Duke Children's Hospital (cont).

THANK YOU!

Contact Information

Michael Powers, MS, RRTDirector, Lung CenterUniversity of Tennessee Medical Center1940 Alcoa Highway, Suite E-110Knoxville, TN 37920Phone: 865-544-9274Fax: 865-544-6607E-mail: mpowers@mc.utmck.edu