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Ventilator Graphics: Not Just Pretty Lines. Ruben D Restrepo, MD, RRT, FAARC Professor The University of Texas Health Science Center at San Antonio. Objectives. Identify graphic display options provided by mechanical ventilators. Describe how to use graphics to
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Ventilator Graphics: Not Just Pretty Lines Ruben D Restrepo, MD, RRT, FAARC Professor The University of Texas Health Science Center at San Antonio
Objectives • Identify graphic display options provided by mechanical ventilators. • Describe how to use graphics to • more appropriately adjust the patient ventilator interface.
Introduction • Monitoring and analysis of graphic display of curves and loops during mechanical ventilation has become critical to determine • how patient is being ventilated • to assess problems occurring during ventilation
Uses of Flow, Volume, and Pressure Graphic Displays • Confirm mode functions • Detect auto-PEEP • Determine patient-ventilator synchrony • Assess and adjust trigger levels • Measure the work of breathing • Adjust tidal volume and minimize overdistension • Assess the effect of bronchodilator administration
Uses of Flow, Volume, and Pressure Graphic Displays • Detect equipment malfunctions • Determine appropriate PEEP level • Evaluate adequacy of inspiratory time in pressure control ventilation • Detect the presence and rate of continuous leaks • Assess inspiratory termination criteria during Pressure Support Ventilation • Determine appropriate Rise Time
Mechanical Ventilation Graphics SCALARS LOOPS
SCALARS Flow/Time Pressure/Time Volume/Time
LOOPS Pressure-Volume Flow-Volume
SCALARS Flow/Time Pressure/Time Volume/Time
Spontaneous Breath Inspiration Time (sec) Flow (L/min) Expiration
Mechanical Breath Inspiration Time (sec) Flow (L/min) Expiration
Typical Flow Patterns SQUARE DECELERATING ACCELERATING SINE
Total cycle time TCT Inspiratory Flow Pattern Beginning of expiration exhalation valve opens Peak inspiratory flow rate PIFR Inspiration Expiratory Time TE Insp. time TI Flow (L/min) Time (sec) Beginning of inspiration exhalation valve closes Expiration
Beginning of expiration exhalation valve opens Duration of expiratory flow Peak Expiratory Flow Rate PEFR Expiratory Flow Pattern Inspiration Expiratory time TE Time (sec) Flow (L/min) Expiration
Inspiratory Pause Inspiration pause Time (sec) } Flow (L/min) Expiration
Patient’s effort Inadequate Inspiratory Flow Active Inspiration Normal Abnormal Time (sec) Flow (L/min)
Air Trapping Auto-PEEP Normal Patient Air Trapping Inspiration Time (sec) Flow (L/min) } Expiration
Response to Bronchodilator After Before Time (sec) Flow (L/min) Long TE PEFR Shorter TE Higher PEFR
SCALARS Flow/Time Pressure/Time Volume/Time
Inspiratory Tidal Volume Volume vs Time Volume (ml) Inspiration Expiration TI Time (sec)
Volume lost Air Leak/Air Trapping Volume (ml) Time (sec)
SCALARS Flow/Time Pressure/Time Volume/Time
Spontaneous Breath Expiration Paw (cm H20) Time (sec) Inspiration
Peak Inspiratory Pressure PIP PEEP Mechanical Breath Paw (cm H2O) Inspiration Expiration TI TE } Time (sec)
CONTROLLED BREATH (Time Triggered) Mechanical Paw (cm H2O) Time (sec) Time Triggered Breath
Assisted Breath(Patient Triggered) Mechanical Paw (cm H2O) Time (sec) Patient Triggered Breath
Assisted vs Controlled Assisted Controlled Pressure (cmH20) Time (sec)
Spontaneous vs. Mechanical Mechanical Inspiration Paw (cm H2O) Spontaneous Expiration Expiration Inspiration Time (sec)
Exhalation Valve Opens Pplateau (Palveolar) Begin Inspiration Components of Inflation Pressure PIP } Transairway Pressure (PTA) Paw (cm H2O) Inspiratory Pause Expiration Time (sec) Begin Expiration
Inadequate Inspiratory Flow Inadequate Flow Adequate Flow Paw (cm H2O) Time (sec)
LOOPS Pressure-Volume Flow-Volume
Pressure-Volume Loop(Type of Breath) E E Vol (ml) I E I I Paw (cm H2O) Spontaneous Controlled Assisted I: Inspiration E: Expiration
Components of Pressure-Volume Loop VT Expiration Volume (mL) Inspiration PIP Paw (cm H2O)
VT PEEP PIP PEEP and P-V Loop Volume (mL) Paw (cm H2O)
Work of Breathing Volume (ml) B A: Resistive Work B: Elastic Work A Pressure (cm H2O)
Upper Inflection Points Lower Inflection Point Inflection Points Volume (mL) Pressure (cm H2O)
Inadequate Sensitivity Volume (mL) Paw (cm H2O) Increased WOB
Air Leak/Air Trapping Volume (ml) Air Leak Pressure (cm H2O)
Inadequate Inspiratory Flow Volume (ml) Active Inspiration Inappropriate Flow Normal Abnormal Paw (cm H2O)
Increased Raw Higher PTA Volume (ml) Higher PTA Paw (cm H2O)
Hysteresis Volume (ml) Normal Hysteresis Abnormal Hysteresis Pressure (cm H2O)
Lung Compliance Changes and the P-V Loop Volume Targeted Ventilation Preset VT COMPLIANCE Increased Normal Decreased Volume (mL) Paw (cm H2O) PIP levels
Lung Compliance Changes and the P-V Loop COMPLIANCE Increased Normal Decreased VT levels Pressure Targeted Ventilation Volume (mL) Preset PIP Paw (cm H2O)
Overdistension With little or no change in VT Normal Abnormal Volume (ml) Pressure (cm H2O) Paw rises
LOOPS Pressure-Volume Flow-Volume
Flow-Volume Loop Inspiration PIFR Volume (ml) FRC VT Flow (L/min) PEFR Expiration
Air Leak Inspiration Flow (L/min) Volume (ml) Air Leak in mL Normal Abnormal Expiration
Air Trapping Inspiration Flow (L/min) Does not return to baseline Volume (ml) Normal Abnormal Expiration
Increased Airway Resistance Inspiration Flow (L/min) Volume (ml) Normal Abnormal “Scooped out” pattern Decreased PEFR Expiration
Airway Secretions/Condensate in the Circuit Inspiration Flow (L/min) Volume (ml) Normal Abnormal Expiration