19 introduction of volumetric capnographyPresentation Transcript
“ Introduction of Volumetric Capnography One Hospital’s Experience ” Presented By: Michael Powers, MS, RRT Director, Lung Center University of Tennessee Medical Center Knoxville, Tennessee
University of Tennessee Medical Center’s Experience and Data
Other Hospital’s Outcome Data
Why to use
How to use
Monitoring CO 2 Elimination
VCO 2 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 PaCO 2 from an ABG, you can answer the question, “Did Vd/Vt change?”
Metabolism (CO 2 Production) CO 2 Elimination (VCO 2 ) PaCO 2 VCO 2 - A Few Basics Things that affect CO 2 elimination Circulation Diffusion Ventilation 1 2
CO 2 Elimination (VCO 2 )
Why Measure VC O 2 ?
Very Sensitive Indicator of
PATIENT STATUS CHANGE
Early Indicator Future Changes in PaCO 2
Another Tool to Assist in Determining When to Draw a Blood
Gas Reduces the # of ABGs
VCO 2 - A Few Basics 3
Integration of Flow & CO 2 Volumetric Capnography
The integration of CO 2 and Flow provides an easy method to obtain previously difficult to obtain parameters
VCO 2 = CO 2 Elimination
Airway Deadspace, Physiologic V D /V T
Integration of Flow & CO 2 EtCO 2 Capnogram Respiratory Rate Capnography Volumetric CO 2 CO 2 Elimination Airway Deadspace Alveolar Ventilation Physiologic 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 CO 2 Waveform EtCO 2 Exhaled Tidal Volume V D V ALV Z Y X
Clinical Application NICO
Ventilation Management Customize ventilator settings : VCO 2 (CO 2 elimination) reflects any changes in ventilation and/or perfusion; it indicates instantly how patient gas exchange responds to ventilator setting changes VCO 2 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 . .
Ratio of Total Deadspace (Vd or Vd phys ) 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 trend screens
Monitoring trends allows for detection of sudden and rapid in VCO 2 , without change in Alveolar Minute Volume or Tidal Volumes.
Drop in VCO 2 suggests change in blood flow to the lungs.
VCO 2 may be due to in C.O. or blood loss.
VCO 2 may be due to in C.O. or malignant hyperthermia.
Coupled with Alveolar Ventilation and Deadspace measurements, this allows for quick patient assessment.
Optimization of PEEP using VCO 2 /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 FiO 2 = 40%. Baseline CO = 4 L/min, Over time SpO 2 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 CmH 2 O. SpO 2 = 95%. Observed a decrease in VCO 2 (150 mL/m) and CO (2.5 L/m) due to increased intrathoracic pressure and decreased venous return. PEEP reduced to 8 cmH 2 O. Both cardiac output (3.4 L/m) and VCO 2 (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 cmH 2 O PEEP increased to 8 cmH 2 O
Alveolar Ventilation per Minute
Amount of Vt that Reaches the Alveoli and is Available for Gas Exchange (Effective Ventilation)
Why Measure MV alv ?
To provides the Most Effective CO 2 Removal
To manage alveolar ventilation and not Vt
Successful Weaning Trial
Shows in spontaneous alveolar ventilation & corresponding decrease in ventilator support.
VCO 2 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 ( VCO 2 followed by in spontaneous tidal volume).
Leads to in PaCO 2 & EtCO 2 .
Return to mechanical ventilation.
Assists clinicians in determining PATIENT RESPONSE.
When used effectively, these utilities may help reduce costly ventilator days.
Here the patient’s ability to maintain Alveolar Ventilation sufficient for CO 2 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).
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 (VCO 2 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 CO 2 . 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) More severe ICU patient population Prefer Noninvasive technologies Pressure on hospital budgets Human resources limited Need to keep ventilator-time as minimal as possible Need to be efficient and costs
University of TN Medical Center Decrease of 39% Decrease of 12%
Re-intubation Rates *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 Decrease of 29% Decrease of 20%
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.
Genesis Medical Center (GMC) is a 500 bed hospital
with three adult Intensive Care units (ICUs) totaling
45 lCU beds. Mechanical Ventilation Hours (MVH)
for fiscal year 2003 totaled 84,000 with an average of
123 hours per patient. We adopted a Mechanical
Ventilation Management Strategy Protocol
incorporating the Respironics Cardiopulmonary
Management System (NICO) in an attempt
to effectively reduce MVH.
Genesis Medical Center (cont).
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).
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 69 41,144 598 2004 118 72,492 612 2003 MVH/pt Total MVH Number of Patients Year
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).
Genesis Medical Center (cont). Decrease of 42.2% Pre-NICO Post-NICO
Genesis Medical Center (cont). Pre-NICO Post-NICO
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
Complications result from mechanical ventilation even
under the best of circumstances; therefore, careful
consideration must be provided for optimal
management strategies on a continual basis. Recent
advances in technology provide clinicians access to
noninvasive monitoring devices with the ability to
display measurable and consistent data, thus,
allowing for a more objective approach to total
Duke Children's Hospital (cont).
Volumetric capnography displays breath-by-breath
measurements of exhaled carbon dioxide during
the entire respiratory cycle. Additionally, the
integration of flow and carbon dioxide elimination