Ventilator Graphics Emeritus Professor Georgia State University Vijay Deshpande, MS, RRT, FAARC Emeritus Professor Georgia State University Atlanta, Georgia, USA Adjunct Visiting Professor, Manipal University College of Allied Health Sciences Manipal, Karnataka, INDIA

Mechanical Ventilation SCALARS LOOPS Graphics

Inspiratory Flow Pattern Peak inspiratory flow rate PIFR Beginning of expiration exhalation valve opens 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

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

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

Volume Ventilation breaths are Volume Cycled Inspiratory Tidal Volume Volume Cycling Volume (ml) Inspiration Expiration TI Time (sec)

Air Leak Volume (ml) Air Leak Time (sec)

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

Inadequate Inspiratory Flow Inadequate Flow Adequate Flow (cm H2O) Paw 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) From: Essentials of Ventilator Graphics- An interactive CD. Vijay Deshpande, MS, RRT and Ruben Restrepo, MD, RRT. Available at www.respiratorybooks.com

SIMV (Volume-Targeted Ventilation) Flow L/m Pressure cm H2O Volume mL Spontaneous Breaths

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) Fig 7.21 PS Breath

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

PSV Flow-Cycle Criteria Peak Inspiratory Flow Flow 40% 20% 5% Simply put, the lower the ESENS, the longer the time before inspiration ends. The higher the ESENS setting, the shorter the inspiratory time. In general, the most appropriate ESENS setting is compatible with the patient’s condition, neither extending nor shortening the patient’s intrinsic inspiratory phase. ESENS can be adjusted by patient assessment. If inspiratory times appear to exceed the inspiratory efforts of the patient, a higher ESENS can be attempted to see if patient comfort improves. If the breath appears to be terminating prematurely, a lower ESENS can be set and patient comfort re-evaluated as well as it’s effect on tidal volume. T 36 36 36 36 36

CPAP + PSV ( BiPAP ) Flow Cycling Volume mL Flow L/m Pressure cm H2O Set PS level Pressure cm H2O CPAP level Volume mL Time (sec) Fig 7.31

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

Air Leak 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 Normal Slope Lower Slope Pressure (cm H2O) Vol (mL) Normal Slope Lower Slope 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

Over-distention Preset Tidal Volume Volume (ml) Pressure (cm H2O) With little or no change in VT Normal Abnormal Volume (ml) Paw rises 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

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

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)

Scalars in Assisted Mode FIGURE 1

Pressure Control Ventilation Flow – Time Scalar TIME CYCLING TI Time Fig 8.16

PCV with long T I or Decreased Lung Compliance Flow No Flow Period Exhalation Valve Opens Time Set TI Inspiratory flow Decreases to zero Fig 8.17

Pressure Control Ventilation with inadequate TI Flow TIME CYCLING Exhalation valve opens TI Time Fig 8.18

Pressure Control Ventilation - Effect of Changes in Lung Compliance on Flow-time scalar A : Decreased Compliance B : Normal compliance C : Increased Compliance Flow TIME CYCLING C A B TI Fig 8.19

Thank You !

Apnea Alarm Patient becomes Apneic Disconnection in Sedated Patient Oversedation in Patients on Low rate SIMV or PCV

“Ventilator inoperative” Alarm Absent Electrical Source (Unplugged) Power Failure “Ventilator inoperative” Alarm Internal Battery has very low charge

High Minute Volume or High Respiratory Frequency Pain Anxiety High Minute Volume or High Respiratory Frequency Hypoxemia

Low PEEP Alarm Active Inspiration Inappropriate Alarm setting A leak in the circuit

Other Useful Alarms High Minute Volume Check Sensitivity setting for trigger level If using external nebulizer, reset the alarm until the treatment is completed, and then reset it to the initial setting. Check physiological causes of increased minute ventilation Low FiO2 Check Gas Source pressures Check Oxygen sensor for proper function (using oxygen analyzer)

Kinking or displacement of the tube Decreased Lung Compliance Increased Resistance Secretions Bronchospasm Kinking or displacement of the tube Pneumothorax Pulmonary Edema, Pleural Effusion High Pressure Alarm Asynchrony (patient fighting) Inadequate Flow Auto PEEP, Improper Sensitivity Coughing

Low Pressure Alarm Leak In the System, Associated with Tracheal Tube Cuff Leak, Chest tube leakage Associated with low minute ventilation or low tidal volume Low Pressure Alarm Patient Disconnection Proximal Pressure Line Disconnected

Low Tidal volume or Low Minute Volume IN VOLUME VENTILATION IN PRESSURE VENTILATION Leak In the System Partial Disconnection Increase in f or decrease in Tidal Volume ( In Volume Ventilation) Increased Resistance and/or Decreased Lung compliance (Leak in the system does NOT Trigger low volume alarm)

Double triggering Volume-targeted ventilation. Notice the circled double volume breath and the pressure-time Waveform to drop below baseline triggering another breath immediately following the first breath. Hallmark of double triggering-peak pressure of the second breath rises as the second breath is stacked on the first breath. From Nilsestuen J, Hargett K. Using Ventilator Graphics to Identify Patient-Ventilator Asynchrony. Resp Care 2005;50(2):202-234

Double triggering Causes Commonly occurs with VC continuous mandatory ventilation Also with PSV with high termination flow criterion High respiratory drive Insufficient respiratory support such as minute ventilation or tidal volume too low with a high respiratory rate. Patient’s Itime (neural) is different (longer) than the ventilator set Itime Small Vt and short inspiratory time

Missed triggers Missed trigger with pressure control ventilation using the expiratory flow waveform. The arrow points to the positive flow deflection that is the hallmark sign of a missed trigger. From: Branson R, Blakeman T, Robinson B. Respiratory Care, 2013

Ineffective inspiratory efforts corrected by flow and expiratory time COPD receiving assist-control ventilation with a constant Vt of 0.55 L. Arrows indicate ineffective ventilation with flow rate at 30 L/min in A. Black arrows indicate ineffective inspiratory efforts. Inspiratory flow rate was increased to 90 L/min which decreased inspiratory time and prolonged expiratory time. This reduced dynamic hyperinflation and the number of ineffective ventilations was reduced. Increasing flow rate can help reduce ineffective triggering in COPD patients with dynamic hyperinflation. During pressure control ventilation reducing inspiratory time will prolong expiratory time to help reduce dynamic hyperinflation. From:Kondili E, Prinianakis G, Georgopoulos D. Patient-Ventilator interaction. Br J Anaesth 2003;91(1):106-119

Inspiratory Rise Time

Inspiratory Time Inspiratory Time Too Short May be able to deliver more tidal volume if inspiratory time lengthen to baseline Normal: Good, Flow into lung has stopped, no extra pressure held in lung that is not wanted Too Long: No Flow at end inspiration Pressure is held in lung, may cause increase lung injury