BY Dr. Yasser Fathi M.B.B.S, M.Sc, M.D Anesthesia Consultant, Head of ICU King Saud Hospital, Unaizah
Objectives For Discussion Respiratory Physiology Pulmonary Graphics BIPAP Graphics Trouble Shootings
Airway Pressures PIP Pr Pplat PEEP 1) Peak Inspiratory Pressure (PIP). Time 2) Plateau Pressure (Pplat). 3) Mean Airway Pressure. 4) Positive End Expiratory Pressure (PEEP).
PEEP Advantages: - Recruits collapsed alveoli. - Improve O2 by FRC. - Shear forces. - WOB in Auto PEEP. - bleeding from mucosa. Disadvantages: - COP. -Barotrauma ( > 15 cmh2o) - ICP. Indications: - To improve oxygenation. - To bleeding.
Peak Flow (Flow Rate) & VT & RR & I:E ratio RR = 15 breaths /min Each breath time = 4 sec. Vt = 1 Lr Peak Flow 60 L/min = 1 L/sec I:E ratio = 1:3 4 sec Insp. Exp. Peak Flow 30 L/min = ½ L/sec I:E ratio = 2:2 = 1:1 Insp. Exp.
Compliance Definition: volume change per unit pressure change V/ P. Lung Compliance = 200 ml/ cmh2o Chest wall Compliance = 200 ml/ cmh2o Total Compliance = 100 ml/ cmh2o 1 Total C 1 1 = + Lung C Chest wall C
Mech. Vent.: Dynamic Compl = Compliance VT PIP - Peep = 40 70 ml/ cmh2o Static Compl = VT Pet - Peep = 70 100 ml/ cmh2o - Causes of Static Compliance Lung Parenchyma Dis. - Causes of Dynamic Compliance Lung Parenchyma Dis. and/or Airway obstruction.
Pulmonary Graphics Waveforms: - Plot pressure / volume / flow against time. - Time is the x axis. Loops: - Plot pressure / volume / flow against each other. - There is no time component.
Volume Flow Pressure Pulmonary Graphics Pressure Modes Waveforms Volume Modes Time
Pulmonary Graphics Pr. - Time Waveforms Pr Pressure Modes Volume Modes PIP A Time B Insp. Pause A = Airway Resistance B = Alveolar Distending Pr. MAP = Area under curve PEEP Insp. starts Exp. starts
Pulmonary Graphics Pr. - Time Waveforms Mode of Ventilation Pr. Pr. Volume Control Pressure Control Pressure Support Time SIMV CPAP BIPAP Time
Pulmonary Graphics Pr. - Time Waveforms Airway Resistance, Lung Compliance Increased Airway Resistance PIP Pplat Lung Compliance PIP Pplat An increase in airway resistance causes the PIP to increase, but Pplat remains normal. A decrease in lung compliance causes both PIP and Pplat to increase.
Pulmonary Graphics Pr. - Time Waveforms Auto PEEP (Air Trapping) Exp. Hold No Such Option Auto PEEP Set PEEP Aut0-PEEP is caused by air trapping in the lungs. Can be detected by applying an expiratory hold maneuver, the waveform rises above the baseline. An acceptable amount of auto-peep should be < 5 Cm H2O
Pulmonary Graphics Flow- Time Waveforms Constant Decelerating Accelerating Sinusoidal -No difference exist in terms of gas exchange or work of breathing. Constant Flow results in better distribution of VT in conditions with low and unequal lung compliance, e.g. lobar Pneumonia. Decelerating Pattern is beneficial in obstructive airway diseases. Accelerating and Sinusoidal Patterns are beneficial in ARDS.
Pulmonary Graphics Flow- Time Waveforms Constant Decelerating Accelerating Sinusoidal Insp. Exp
Pulmonary Graphics Flow- Time Waveforms Auto PEEP (Air Trapping) Insp. Exp
Pulmonary Graphics Flow- Time Waveforms Response to Bronchodilator Insp. Exp
Pulmonary Graphics Pr - Volume Loops Spontaneous Breath Inspiration Expiration Vol 0.6 CPAP Clockwise Pressure -20-10 0 10 20 cmh 2 O
Pulmonary Graphics Pr - Volume Loops Pressure Control Breath Inspiration Expiration 0.6 AntiClockwise Pressure -20-10 0 10 20 30 cmh 2 O
Pulmonary Graphics Pr - Volume Loops Volume Control Breath Inspiration Expiration 0.6 AntiClockwise Pressure -20-10 0 10 20 30 cmh 2 O
Pulmonary Graphics Pr - Volume Loops Volume Control Breath with PEEP Inspiration Expiration 0.6 AntiClockwise Pressure -20-10 PEEP 10 20 30 cmh 2 O
Pulmonary Graphics Assissted Breath Inspiration Expiration Vol. 0.6 Pr - Volume Loops -Clockwise counter Clockwise (Fish Tail). Pressure -20-10 0 10 20 30 cmh 2 O
Pulmonary Graphics Pr - Volume Loops Work of Breathing Vol Inspiration Expiration Pr cmh 2 O Spontaneous Assisted Breath
Pulmonary Graphics Pr - Volume Loops Airway Resistance Inspiration Expiration 0.6 Pressure -20-10 0 10 20 30 cmh 2 O As resistance increases, the loop wider. inspiratory resistance.kinked ETT or patient biting. in expiratory resistance is more common, B. Asthma, COPD
Volume Pulmonary Graphics Pr - Volume Loops Compliance Pressure Compliance Loops moves down & to the right. Angle between imaginary line and X axis becomes < 40ᴼ
Volume Pulmonary Graphics Pr - Volume Loops Compliance (Pressure Mode) Compliance Compliance Pressure Preset PIP Constant Pr variable Vt
Volume Pulmonary Graphics Pr - Volume Loops Compliance (Volume Mode) Preset Vt C C PIP levels Constant Vt. Variable Pressure Pressure
Pulmonary Graphics Pr - Volume Loops Air Leak Inspiration Expiration Vol. 0.6 Pressure -20-10 0 10 20 30 cmh 2 O The expiratory portion of the loop doesn t return to baseline. This indicates a leak
Pulmonary Graphics Pr - Volume Loops Bird Beaking Inspiration Expiration Vol. Pressure Normal loops have a typical "football" shape. Beaking means excessive pressure with minimal or no volume increase overdistension & Barotruama.
Pulmonary Graphics Pr - Volume Loops Flow Starvation Inspiration Expiration Vol. Pressure A wavy inspiratory curve will be seen when flow is set less than patient's inspiratory needs WOB, anxiety and frustration..
Pulmonary Graphics Pressure-Volume Loops Volume is plotted on the y-axis, Pressure on the x-axis. Spontaneous breaths go clockwise and positive pressure breaths go counter clockwise. The bottom of the loop will be at the set PEEP level. It will be at 0 if there s no PEEP set. If an imaginary line is drawn down the middle of the loop, the area to the right represents insp. resistance and the area to the left represents exp. resistance.
Pulmonary Graphics Flow - Volume Loops Flow (L/min) PIFR Inspiration Expiration Vt Volume (ml) PEFR
Pulmonary Graphics Air Leak Flow (L/min) Flow - Volume Loops Inspiration Expiration Volume (ml)
Pulmonary Graphics Flow - Volume Loops Auto PEEP (air trapping) Flow (L/min) Inspiration Expiration Volume (ml)
Pulmonary Graphics Flow - Volume Loops Water Pooling in Circuit Flow (L/min) Inspiration Expiration Volume (ml)
Pulmonary Graphics Flow - Volume Loops Airway Resistance Flow (L/min) Inspiration Expiration Volume (ml) Scooping PEFR
Pulmonary Graphics Flow - Volume Loops Flow is plotted on the Y axis and volume on the X axis. Inspiration is above the horizontal line and expiration is below. Flow volume loops used for ventilator graphics are the same as ones used for Pulmonary Function Testing, (usually upside down). Can be used to determine the PIF, PEF, and Vt. Looks circular with spontaneous breaths
Bilevel Ventilation (BIPAP) Burton Bennett's 840
Bilevel Ventilation (BIPAP) Is a spontaneous breathing mode which Provides two levels of CPAP named (P Low and P High ) and allows spontaneous breathing at both levels. Ventilator settings: RR, (P Low and P High ) and (TI and TE). Substantial improvements for spontaneous breathing and better synchronization.
Bilevel Ventilation (BIPAP) 30 Pr Spontaneous Breaths Synchronized Transitions Spontaneous Breaths -10
Initial Settings Bilevel Ventilation (BIPAP)
Bilevel Ventilation (BIPAP) To Improve Oxygenation
Bilevel Ventilation (BIPAP) To Improve Ventilation
Bilevel Ventilation (BIPAP) At either pressure level the patient can breath spontaneously spontaneous breaths may be supported by PS on the low set pressure (PLow). if PS is set higher than (P High ), PS supports spontaneous breath at both set pressures (P Low and P High ).
Bilevel Ventilation (BIPAP) 60 P High P High + PS Pressure Support P aw cmh 2 0 P Low -20 1 2 3 4 5 6 7
Trouble Shootings Inadequate Pressurization Leads to WOB, anxiety. Flow Rate ( Volume Modes), Rise Time (Pressure modes)
Trouble Shootings Double Triggering 2 insp. Waves with short exp. Time in between. Common in strong patients with deep insp. drive. Due to inadequate Insp. time. Insp. Time
Trouble Shootings Undetected Patient s effort Flow sensitivity > Pressure sensitivity. Trigger Sensitivity ( Flow or Pressure value)
Trouble Shootings Auto Triggering Exp. Leak interpretated as spontaneous breath. Prevent Leak, Trigger Sensitivity ( Flow or Pressure value)
VT Trouble Shootings AUTO PEEP Concept: M.V. of a pt with airway resistance. If exp. time is short incomplete exhaling of VT before the next insp. Causes: * Exp. Flow limitation. (COPD & B. Asthma) * Min. Ventilation. * Narrow ETT, long tubing. Dynamic Hyperinflation Start of Auto PEEP
Trouble Shootings AUTO PEEP Measurement: Unlike ventilator PEEP, Auto PEEP does not reflect on the ventilator pressure gauge. M.V. patient: End Expiration occlusion technique (Exp. Hold). Spontaneously Breathing patient: Negative Esophageal Pr. just before inspiration.
Trouble Shootings AUTO PEEP Clinically encountered Values: COPD :Stable 9 CmH2o COPD: exacerb + spont 13 COPD: exacerb + M.V. 22 B. Asthma: exacerb + M.V. 22 Pulm. Edema: on M.V. 8
Trouble Shootings AUTO PEEP Strategies: Bronchodilators. Sedation ± Paralysis (Not in NIV) Min. Ventilation (RR, VT). Exp. Time Side Effects: Bl. Pr. Barotrauma WOB
Trouble Shootings AUTO PEEP Will you use an external PEEP to # Auto PEEP: Yes as patient is spontaneously breathing to WOB. Pr. 20 Trigger Sensitivity (1) 10 Auto PEEP PEEP 8 0-1
HOME MESSAGE It s not the ventilator mode that makes a difference It s the skills of the clinician. Ventilator waveforms analysis is an integral component in the management of a mechanically ventilated patient.
HOME MESSAGE Develop a habit of looking at the right waveform for the given mode of patient ventilation. Always look at the inspiratory and expiratory components of the flowtime waveform. Change the scale or speed of the waveform for better interpretation.
Thank You