Provided by UFHealth Respiratory Care ServicesThis presentation requires audio

Aug 2016

Instructions for Use� Best viewed as slideshow with audio

� Hit “F5” to start slideshow (intended as slideshow)� Audio icon seen in lower right of page will auto-play� Audio Script can be found in the notes section of each

slide, if needed. (Not while in slideshow view)� Arrow at top left of page links to the Table of Contents� Table of Contents contains links to each section

Structure of Content� Lung Volumes & Capacities� Dead Space Ventilation� Respiratory Mechanics� Ideal Body Weight Based Tidal Volume� Survey of Ventilator Settings� Ventilator Settings Relative to Labs & Monitoring Data� Mandatory & Spontaneous Breaths� Modes� Breath Types� Standard Initiation of a Mechanical Ventilator� Non-Invasive Mechanical Ventilation� Liberation from Mechanical Ventilation� Resources : Gas Laws, Other study materials

� VT = Tidal Volume (Basic inhale/exhale)

� VC = Vital Capacity (Complete inhale/exhale)� (also FVC = Forced Vital Capacity)

� FRC = Functional Residual Capacity (Reserve and Residual Volumes)

Dead Space Ventilation� Ventilation without perfusion.

� Examples: � Mechanically Induced - Artificial Airway� Anatomical – Trachea, Bronchus, etc.� Alveolar - Lack of perfusion at the alveolar level

Mechanical Dead Space

Respiratory Mechanics� (Static) Resistance

� Δ Pressure / Δ Flow

� Static Compliance

� Δ Volume / Δ Pressure

� Dynamic Compliance� Approximation of compliance in the spontaneously

breathing patient

Ideal Body Weight Based VT� Selected VT is derived from IBW

based on height and sex.� Currently accepted

� 6-8mL/kg� Exceptions

� ARDS 4-6mL/kg

� Male 178cm� 75 kg IBW� 450-600 mL VT

75kg x 6mL/kg = 450mL75kg x 8mL/kg = 600mL

Available Ventilator Settings� Rate� VT� FIO2� ITime� ETime� ESens� I:E� Flow� Trigger (Flow or

Pressure)

� Rise Time� PI� PEEPHigh� PEEPLow� PS� VS� PEEP� ATC� Waveform Type� LC

� THigh� TLow� Modes

� (AC, SIMV, etc.)

� Breath Types� (VC, PC, etc.)

Common Ventilator Settings� Rate� VT� FIO2� ITime� ETime� ESens� I:E� Flow� Trigger (Flow or

Pressure)

� Rise Time� PI� PEEPHigh� PEEPLow� PS� VS� PEEP� ATC� Waveform Type� LC

� THigh� TLow� Modes

� (AC, SIMV, etc.)

� Breath Types� (VC, PC, etc.)

Relating Parameters & Data to Ventilation� Rate:

� Respiratory Rate (rr) or Frequency (f) or Breaths per Minute (bpm)� Tidal Volume

� In Pressure modes, Pressure is set to achieve the desired tidal volume (ie: PI, PInsp, P, PC, etc.)

� VT (Exhaled Tidal Volume = VTE) (expressed in mLs)� Minute Ventilation

� f x VT = VE (expressed in L/min)� Lab Data

� PaCO2

� Monitoring Data� Capnography (EtCO2)

� Will always be less than PaCO2. Normal = 5-10 < PaCO2

ETCO2

Mandatory Pressure

Spontaneous Pressure

Factors of Ventilation

Relating Parameters & Data to Oxygenation� Ventilator Settings

� FiO2� Positive End Expiratory Pressure (PEEP) or Continuous

Positive Airway Pressure (CPAP)� Ventilator Monitoring

� Mean Airway Pressure (PMEAN) or (MAP)� Lab Data

� PaO2� Monitoring Data

� SpO2

� Related Volume/Capacity� Functional Residual Capacity (FRC)

FiO2

Factors of Oxygenation

Mandatory & Spontaneous Breaths� Mandatory breaths are triggered by time via a set rate and

attempt to synchronize with patient effort, if present, and are modified by the Mode utilized.� All mandatory breaths are controlled breaths

� Spontaneous breaths are any breaths that are patient triggered that are not mandatory� Spontaneous breaths can be unassisted, partially or fully

assisted breaths are chosen depending on the Mode utilized� Example: Set rate = 12bpm, Total rate = 20bpm

� Mandatory – 12 breaths roughly seen every 5 seconds apart� Spontaneous – 8 breaths seen randomly between the

mandatory breaths

Modes� Modes determine when the mechanically assisted

breaths are to be provided to the patient

� Available common modes:� Spontaneous (SPONT)� Assist Control (AC)� Synchronized Intermittent Mandatory Ventilation

(SIMV)

Mode: Spontaneous (SPONT)� SPONT does not have a set rate and the spontaneously

breathing patient is entirely responsible for triggering breaths. Breaths may be fully, partially or not supported with breath types which include Pressure Support or Volume Support.

Mode: Spontaneous

Mode: Assist-Control Ventilation (AC)� AC delivers a set number of mandatory breaths of a set

breath type over time. Spontaneous breaths are assisted with a full mandatory breath of the same breath type. Each breath is the same whether it was triggered by time or by the spontaneous patient.

Mode: Assist Control

Mode: Synchronized Intermittent-Mandatory Ventilation (SIMV)� SIMV attempts to synchronize a set number of

mandatory breaths over time with patient effort to promote synchrony. SIMV allows spontaneous breaths that are not supported between those mandatory breaths. Spontaneous breaths may be partially or fully supported with Pressure Support breaths.

Mode: SIMV

Breath Types� Breath types determine how the mechanically assisted

breaths are to be provided to the patient and generally involve a set or targeted pressure or volume.

� Volume Limited� Volume Control (VC)

� Pressure Limited / Volume Targeted� Pressure Control (PC)� Pressure Regulated Volume Control (PRVC or VC+)� Pressure Support (PS)� Volume Support (VS)

Breath Type: Volume Control (VC)� Set Tidal Volume (VT)� Set Flow� Pressure is variable� Breaths are mandatory with a set rate� Some static measurements only measureable in VC

due to the ability to control flow as a constant.� Static measurements include Static Compliance (CST) &

Airway Resistance (RAW).� Measurable only if patient is not spontaneously

breathing.

Breath Type: Pressure Control (PC)� Set Pressure (Pinsp or ΔP)� Set Inspiratory Time (ItimeorTi)

� If inappropriately set can lead to patient-ventilator asynchrony.

� Variable Flow� Promotes patient synchrony

� Volume is variable� Breath type is mandatory with a set rate

Breath Type: Pressure Regulated Volume Control (PRVC), also (VC+)� Pressure Regulated with a target VT

� Changes pressure each breath to attempt to deliver targeted set VT

� Volume Target is set� Variable Flow

� Promotes patient synchrony� Set Inspiratory Time (ItimeorTi)

� If inappropriately set can lead to patient-ventilator asynchrony.

� Breath type is mandatory with a set rate

Breath Type: Pressure Support (PS)� Partially or fully assisted breath type triggered and cycled

by the patient.� Available in SIMV or Spontaneous modes� Breath type not associated with a set rate or mandatory

breath� Set Pressure� Variable Volume� Variable Flow

� Promotes patient synchrony� Triggered & Cycled by patient

� Promotes patient synchrony

Breath Type: Volume Support (VS)� Fully assisted breath type triggered and cycled by the patient.� Available in Spontaneous Mode� Breath type not associated with a set rate or mandatory breath� Pressure regulated with a target VT

� Changes pressure each breath to attempt to deliver targeted volume� Volume Target is Set� Variable Flow

� Promotes patient synchrony� Triggered by patient

� Promotes patient synchrony

Standard Initiation of a Mechanical Ventilator� Mode and Breath Type = according to desired goal and patient

effort and disease process� RR = 12-20 bpm� PEEP = 5-10 cmH2O� FiO2 = 21-100% (Current % or higher)� VT = Based on IBW (4-6mL/kg of IBW)

� Or a set pressure to achieve same volume if in pressure mode� If in SIMV or Spontaneous, PS would also be set for an adequate

spontaneous VT � ITime = 0.8-1.5 sec if using PC or PRVC (VC+)

� Please refer to service/unit specific practice and/or protocol.� Adjustments after initial setup are based on labs and

monitoring.

Non-Invasive Ventilation (NIV)� Positive pressure ventilation and/or oxygenation

without an artificial airway.� CPAP = PEEP� BiPAP = PEEP & PS� Consider NIV if the goal is to prevent an artificial

airway or one is not an option.� Patient must be spontaneously breathing.

Liberation from Mechanical Ventilation� Unit/service specific practice (Daily Wake Up Best

MICU, 4West, 4East, 82 Neuro with Airway Care Scores, CVICU Fast Track).

� Atrophy of diaphragm occurs hourly on a mechanical ventilator, so every minute counts

� Weaning from a mechanical ventilator is so important that even before a ventilator is initiated, having a plan to liberate the patient is prudent.