How To Ventilate ICU Patient Dr Mohammed Bahzad MBBS.FRCPC,FCCP,FCCM Head Of Critical Care Department Mubarak Alkbeer Hospital

Aims l Get oxygen in l Get carbon dioxide out l Minimize adverse effects l Maximize patient comfort

Case A l 60 kg male l Post operative – complicated wipel procedure l No previous lung or heart disease l Still paralyzed

Make the ventilator fit the patient

Mode l Non-invasive l Invasive –Assist control –Pressure control –SIMV –(Pressure support) l Pick a mode you understand and are familiar with

Assist control l Set tidal volume l Inspiratory-expiratory cycling –Time cycled l Time is set l Ventilator adjusts flow to deliver set tidal volume in the set time –Volume cycled

Assist control l Breaths: –Ventilator initiated (control breaths) –Patient initiated (assist breaths) –Set minimum frequency l Characteristics of each inspiration are the same –Not affected by whether breath is control breath or an assist breath

700 ml l/min 50 cmH 2 O Assist control Pressure Flow Volume T

700 ml l/min 50 cmH 2 O Assist control Pressure Flow Volume T

Assist control l Set –Minimum respiratory rate l Patient’s spontaneous respiratory rate < set rate  ventilator gives additional control breaths to make up difference l Patient’s spontaneous rate > set rate  no control breaths

Volume control l Set –Minimum respiratory rate –Tidal volume

Volume control l Set –Minimum respiratory rate –Tidal volume –Inspiratory time or I:E ratio –Inspiratory pause time

Volume control l Longer inspiratory time –Improved oxygenation l Higher mean airway pressure l Re-distribution –Lower peak airway pressure l More time available to deliver set tidal volume l Shorter inspiratory time –Less risk of gas trapping and PEEP i –Less effect on cardiovascular system

Setting I:E, inspiratory flow time, pause time l Nomenclature Time Volume

Setting I:E, inspiratory flow time, pause time l Nomenclature Time Volume Inspiratory flow time

Setting I:E, inspiratory flow time, pause time l Nomenclature Time Volume Inspiratory pause time

Setting I:E, inspiratory flow time, pause time l Nomenclature Time Volume Inspiratory time

Setting I:E, inspiratory flow time, pause time l Nomenclature Time Volume Inspiratory timeExpiratory time

Setting I:E, inspiratory flow time, pause time l Nomenclature Time Volume Respiratory cycle time

I:E as a ratio & inspiratory pause time as a percentage Time Volume 6 secs 12 10%

I:E as a ratio & inspiratory pause time as a percentage Time Volume 3 secs 12 10%  Respiratory rate

Absolute inspiratory time, inspiratory flow time as a function of flow rate Time Volume 6 secs 2 secs4 secs 0.5 s

Absolute inspiratory time, inspiratory flow time as a function of flow rate Time Volume 3 secs 2 secs 0.5 s  Respiratory rate without changing Inspiratory time or inspiratory flow 1 sec

Absolute inspiratory time, inspiratory flow time as a function of flow rate Time Volume 3 secs 2 secs 1.5 s  inspiratory flow 1 sec

Absolute inspiratory time, inspiratory flow time as a function of flow rate Time Volume 3 secs 1 sec 0.5 s  Absolute inspiratory time 2 sec

Time Volume 3 secs 2 secs 0.5 s  Respiratory rate without changing inspiratory flow or inspiratory pause time 1 sec Inspiratory flow time as a function of flow rate, absolute pause time

Time Volume 3 secs 1 sec 0.5 s  inspiratory flow 2 sec

Inspiratory flow time as a function of flow rate, absolute pause time Time Volume 3 secs 0.8 sec 0.3 s  inspiratory pause time 2.2 sec

Volume control l Set –Minimum respiratory rate –Tidal volume –Inspiratory time or I:E ratio l Directly/indirectly –Inspiratory pause time l Directly/indirectly –PEEP

Assist control l Advantages –Relatively simple to set –Guaranteed minimum minute ventilation –Rests muscles of respiration (if properly set) l Disadvantages –Not synchronized –Patient may “lead” ventilator –Inappropriate triggering may result in excessive minute ventilation –  lung compliance   alveolar pressure with risk of barotrauma –Often requires sedation to achieve synchrony.

Pressure control l Pressure preset assist/control ventilation l Similar to volume control except pressure is preset

PEEP PC above PEEP Pressure Flow Time Volume

PEEP PC above PEEP Pressure Flow Time Volume Normal inspiratory timeShort inspiratory time

Pressure control l Advantages –Relatively simple –Avoids high inspiratory pressures –Rests muscles of respiration –Improved oxygenation l Disadvantages –Not synchronized –Inappropriate triggering may  excessive minute ventilation –Change in lung compliance or resistance  change in tidal volume –Often requires sedation

Pressure support l Nomenclature –Inspiratory assist –Assisted spontaneous breathing

Pressure support PEEP PS above PEEP Pressure Flow Volume Maximum inspiratory flow Set % of max inspiratory flow

Pressure support l Advantages –Simple to set –Avoids high inspiratory pressures –Better patient- ventilator synchrony –Unloads respiratory muscles l Disadvantages –No apnoea back-up in older ventilators –Change in lung compliance or resistance  change in tidal volume

Pressure support l Pressure support of cmH 2 O required to overcome the additional work of breathing due to breathing through ETT and demand valve l Patients who require pressure support of < 6 cmH 2 O can probably be extubated

SIMV (& pressure support) l SIMV almost always combined with pressure support

SIMV l Patient receives a minimum number of mandatory breaths l Able to breath in between these breaths –± pressure support breaths

SIMV Pressure Flow PEEP Time Trig Time Mandatory breath

SIMV Pressure Flow PEEP Time Trig Time Pressure support breath

Mandatory breaths l Volume control breaths –Set tidal volume l Pressure control breaths –Set pressure

Mandatory breaths l Synchronized with patients inspiratory efforts

Triggering l Effect of triggering depends on its timing –Close to time that a mandatory breath is due (during SIMV period) l ⇒ synchronized mandatory breath –Other times (during spontaneous period) l ⇒ pressure support breath

SIMV period TT Spontaneous period

SIMV period Spontaneous period

Settings l F i O 2 l SIMV rate –=mandatory breath rate l SIMV period (some ventilators) l Tidal volume (or inspiratory pressure) l I:E ratio l Pressure support l PEEP

Volume control l Set –Minimum respiratory rate –Tidal volume –Inspiratory time or I:E ratio l Directly/indirectly –Inspiratory pause time l Directly/indirectly –PEEP

SIMV & PS l Advantages –Better patient- ventilator synchrony –Guaranteed minimum minute ventilation l Disadvantages –Complicated mode

What mode? l Largely apnoeic patient –Control of minute ventilation important l Assist control –Control of peak pressure important l Pressure control l Intermittent spontaneous breaths –SIMV l Regular spontaneous breaths, improving condition –Pressure support

Case A l 60 kg male l Post operative – complicated wipel procedure l No previous lung or heart disease l Still paralyzed

54 Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i ! :32  Charles Gomersall 2003 Mode Volume Control Automode Admit patient NebulizerStatus Additional values Set ventilation mode Volume control  Automode Ti =1.33 s (33%) Tidal volume 500 Resp. Rate 12 PEEP 5 O 2 conc. 100 I:E 1:2.0 T. pause 10 T. Insp. rise 5 Trigger sensitivity V Basic I:ETrigger. CancelAccept.

Assess l Chest movement l Breath sounds l Saturation

pH7.23 P a CO kPa (61 mmHg) PaO2PaO kPa (413 mmHg) HCO mmol/l Base excess+3 Saturation100%

Increasing alveolar ventilation l Increase tidal volume l Increase respiratory rate –Increase risk of gas trapping Flow x resistance (Volume/compliance) + PEEP

58 Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i ! :32  Charles Gomersall 2003 Mode Volume Control Automode Admit patient NebulizerStatus Additional values Basic I:ETrigger. Additional settings 700 ml l/min 50 cmH 2 O Recording Ppeak Pplat Pmean PEEP RR O2O2 Vee I:E MVe MVi VTi VTe : Moderately high Pplat

59 Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i ! :32  Charles Gomersall 2003 Mode Volume Control Automode Admit patient NebulizerStatus Additional values Set ventilation mode Volume control  Automode Ti =1.33 s (33%) Tidal volume 500 Resp. Rate 15 PEEP 5 O 2 conc. 50 I:E 1:2.0 T. pause 10 T. Insp. rise 5 Trigger sensitivity V Basic I:ETrigger. CancelAccept.  Resp rate  FiO 2

Case A l Patient starts to wake up l Triggering ventilator frequently –some breath stacking l Change to pressure support mode

61 Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i ! :32  Charles Gomersall 2003 Mode Volume Control Automode Admit patient NebulizerStatus Additional values Set ventilation mode Pressure support  PS above PEEP 15 PEEP 5 O 2 conc. 40 T. Insp. rise 5 Insp. cycle off 5 Trigger sensitivity V Basic I:ETrigger. CancelAccept.

Other settings l Trigger sensitivity –  sensitivity preferable l Flow triggering generally more sensitive than pressure triggering l  flow or  pressure   sensitivity

Assess l Chest movement l Respiratory rate & effort l Saturation

l Respiratory rate l Tidal volume l Synchrony l Blood gases Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i Mode Volume Control Automode Admit patient NebulizerStatus. 40 Assess Ppeak (cmH 2 O) Pmean 12 PEEP RR (b/min) O 2 (%) 46 MVe (l/min) VTi 701 VTe 693 Additional settings Additional values

Case B l 72 year old, 60 kg man with history of asthma l Presents with severe bilateral pneumonia

l Pressure control mode l FiO l Insp pressure 10 above PEEP 5 l RR 20 l I:E= 1:2 Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i Mode Pressure Control Automode Admit patient NebulizerStatus. 100 Case B Ppeak (cmH 2 O) Pmean 12 PEEP RR (b/min) O 2 (%) 100 MVe (l/min) VTi 201 VTe 193 Additional settings Additional values

l Pressure control mode l FiO l Insp pressure 20 above PEEP 5 l RR 20 l I:E= 1:2 Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i Mode Pressure Control Automode Admit patient NebulizerStatus. 60 Case B Ppeak (cmH 2 O) Pmean 12 PEEP RR (b/min) O 2 (%) 66 MVe (l/min) VTi 501 VTe 493 Additional settings Additional values

Case B pH7.43 P a CO kPa (38 mmHg) PaO2PaO2 6.9 kPa (52 mmHg) HCO mmol/l Base excess-2 Saturation84%

Look for causes of desaturation l Chest movement l Breath sounds l Ventilator malfunction l CXR

l Options ? –  FiO 2 –  inspiratory pressure –  inspiratory time –  PEEP Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i Mode Pressure Control Automode Admit patient NebulizerStatus. 60 Improving oxygenation Ppeak (cmH 2 O) Pmean 12 PEEP RR (b/min) O 2 (%) 66 MVe (l/min) VTi 501 VTe 493 Additional settings Additional values Mean alv pre

l Options ? –  FiO 2 –  inspiratory pressure –  inspiratory time –  PEEP Start breath O 2 breaths Exp. hold Insp. hold Main screen Menu Quick start Alarm profile SaveTrends i Mode Pressure Control Automode Admit patient NebulizerStatus. 60 Improving oxygenation Ppeak (cmH 2 O) Pmean 12 PEEP RR (b/min) O 2 (%) 66 MVe (l/min) VTi 501 VTe 493 Additional settings Additional values

Re-assess l Pulse oximetry l Arterial blood gas

Summary l Chose the mode that fits the patient l Set the ventilator to achieve your aims l Often more than one way to achieve your aims –Select the method with the least adverse effects

Thank You