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

Inspiratory Flow Pattern Beginning of expiration exhalation valve opens Peak inspiratory flow rate PIFR Inspiration Insp. time TI Expiratory Time TE Flow (L/min) Total cycle time TCT Time (sec) Beginning of inspiration exhalation valve closes Expiration

Expiratory Flow Pattern Beginning of expiration exhalation valve opens Inspiration Expiratory time TE Time (sec) Flow (L/min) Duration of expiratory flow Expiration Peak Expiratory Flow Rate PEFR

Inspiratory Pause } Inspiration Flow (L/min) Time (sec) Expiration

Inadequate Inspiratory Flow Patient’s effort Active Inspiration Normal Abnormal Time (sec) Flow (L/min)

Air Trapping Inspiration Normal Patient Time (sec) Flow (L/min) } Auto-PEEP Expiration

Response to Bronchodilator Before After 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 Inspiratory Tidal Volume Volume (ml) Inspiration Expiration TI Time (sec)

Air Leak/Air Trapping Volume (ml) Volume lost Time (sec)

SCALARS Flow/Time Pressure/Time Volume/Time

Spontaneous Breath Expiration Paw (cm H20) Time (sec) Inspiration

Peak Inspiratory Pressure Mechanical Breath Peak Inspiratory Pressure PIP Paw (cm H2O) Inspiration Expiration TI TE } PEEP 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 Pressure (cmH20) Time (sec)

Spontaneous vs. Mechanical Inspiration Paw (cm H2O) Spontaneous Expiration Expiration Inspiration Time (sec)

Components of Inflation Pressure PIP } Transairway Pressure (PTA) Paw (cm H2O) Exhalation Valve Opens Pplateau (Palveolar) Inspiratory Pause Expiration Begin Inspiration Time (sec) Begin Expiration

Inadequate Inspiratory Flow Inadequate Flow Adequate Flow (cm H2O) Paw Time (sec)

LOOPS Pressure-Volume Flow-Volume

Pressure-Volume Loop (Type of Breath) Vol (ml) I E I I Paw (cm H2O) Controlled Assisted Spontaneous I: Inspiration E: Expiration

Components of Pressure-Volume Loop VT Expiration Volume (mL) Inspiration PIP Paw (cm H2O)

PEEP and P-V Loop VT PIP Volume (mL) PEEP Paw (cm H2O)

Work of Breathing B A: Resistive Work B: Elastic Work A Volume (ml) Pressure (cm H2O)

Inflection Points Upper Inflection Points Lower Inflection Point Volume (mL) Lower Inflection Point 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 Normal Hysteresis Abnormal Hysteresis Volume (ml) 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 Increased Normal Decreased VT levels Pressure Targeted Ventilation Volume (mL) Paw (cm H2O) Preset PIP

With little or no change in VT 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 FRC VT PEFR Expiration Flow (L/min) Volume (ml) FRC VT Flow (L/min) PEFR Expiration

Air Leak Normal Abnormal Inspiration Expiration Volume (ml) Flow (L/min) Volume (ml) Air Leak in mL Normal Abnormal Expiration

Air Trapping Normal Abnormal Inspiration Expiration 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

Modes of Ventilation Mechanical Spontaneous Volume Targeted Pressure

Spontaneous Breath Flow L/m Pressure cm H2O Volume mL Time (sec)

CPAP Flow L/m Pressure cm H2O CPAP level Volume mL Time (sec)

PSV Patient Triggered, Flow Cycled, Pressure limited Mode Time (sec) Flow Cycling Flow L/m Set PS level Pressure cm H2O Volume mL Time (sec)

CPAP + PSV Flow Cycling Flow L/m Pressure cm H2O Volume mL Time (sec) Set PS level Pressure cm H2O CPAP level Volume mL Time (sec)

Modes of Ventilation Mechanical Spontaneous Volume Targeted Pressure

Controlled Mode (Volume- Targeted Ventilation) Time triggered, Flow limited, Volume cycled Ventilation Preset Peak Flow Flow L/m Dependent on CL & Raw Pressure cm H2O Preset VT Volume Cycling Volume mL Time (sec)

Assisted Mode (Volume-Targeted Ventilation) Patient triggered, Flow limited, Volume cycled Ventilation Flow L/m Pressure cm H2O Preset VT Volume Cycling Volume mL Time (sec)

SIMV (Volume-Targeted Ventilation) Pressure Flow Volume (L/min) (cm H2O) (ml) Spontaneous Breaths

Controlled Mode (Pressure-Targeted Ventilation) Time Triggered, Pressure Limited, Time Cycled Ventilation Time-Cycled Pressure Flow Volume (L/min) (cm H2O) (ml) Set PC level Time (sec)

Assisted Mode (Pressure-Targeted Ventilation) Patient Triggered, Pressure Limited, Time Cycled Ventilation Time-Cycled Pressure Flow Volume (L/min) (cm H2O) (ml) Set PC level Time (sec)

SIMV Mode (Pressure-Targeted Ventilation) Flow Volume (L/min) (cm H2O) (ml) Set PC level Time (sec) Spontaneous Breath

SIMV + PS (Pressure-Targeted Ventilation) Time-Cycled Flow-Cycled Pressure Flow Volume (L/min) (cm H2O) (ml) Set PC level Set PS level Time (sec) PS Breath

SIMV+PS (Volume-Targeted Ventilation) Flow-cycled Flow Pressure Volume (L/min) (cm H2O) (ml) Set PS level PS Breath

SIMV + PS + CPAP (Pressure-Targeted Ventilation) Flow Volume (L/min) (cm H2O) (ml) Set PC level Set PS level CPAP level Time (sec)

SIMV+PS + CPAP (Volume-Targeted Ventilation) Flow Pressure Volume (L/min) (cm H2O) (ml) Set PS level CPAP level Time (sec)

THANK YOU NYC