mechanical ventilation in emergency department

Mechanical Ventilation in Emergency Room

Dr.Venugopalan P P DA,DNB,MNAMS,MEM [GWU] Director ,Emergency Medicine Aster DM Healthcare -India

Executive Director -Active Network Group of Emergency Life Savers

Faculty presentation in Second annual conference on `Emergency medicine conducted by Ananthapuri Hospital Trivandrum

19.06.2016

Background Intubation &mechanical ventilation, is a common life-saving intervention Good understanding of techniques to optimise mechanical ventilation will minimise complications.Effects of ventilator-induced lung injury are delayed and not seen while patients are in the EDMechanical ventilation - ED approach is different .Ventilatory strategies - different disease processes to protect pulmonary parenchyma while maintaining adequate gas exchangeNoninvasive ventilation - avoid the risks and complications of tracheal intubation

Understanding of Mechanical Ventilation in ED

Basics and beyond ….

Session tries to answer this

Why ventilation in ED?

How to initiate ?

What are the problems involved ?

What are the special situations to be considered?

What are the trouble shoots and how it be managed ?

What are the ED role in preventive care ?

Why mechanical ventilation in ED?

Clinical- Airway-Breathing- Circulation-Disability

Lab

Clinical Airway

Airway protection

Clinical Breathing

Apnea Hypoventilation

Respiratory distress +AMS

Increased work of breathing unrelieved by noninvasive methods

Clinical Circulation

Severe circulatory shock

Clinical Disability

Controlled hyperventilation

GCS less than 8

Laboratory Indications

“8” Sets of Indications to start mechanical ventilation in ED

1 Airway Airway protection2 Breathing Apnea,Distress3 Circulation Shock4 Disability Low GCS5 Arterial Blood Gas PaO2,PaCO2&PH6 Volume VC<10ml/Kg7 Pressure Neg.Insp.Pr<25cmH2O8 Flow FEV1<10ml/Kg

Pearls No absolute contraindications exist to mechanical ventilation. The need for mechanical ventilation is best made early on clinical grounds.A good rule of thumb - if the practitioner is thinking that mechanical ventilation is needed, then it probably yes. Waiting for return of laboratory values can result in unnecessary morbidity or mortality.

How to do it?Know the modes and supports

Know how to set it

Modes

Volume -cycled

Pressure -cycled

High frequency oscillatory support

Volume cycled

Inhalation till pre-set Tidal volume delivered

Passive exhaustion

Constant inspiratory flow

Peak inspiratory pressure >Plateau Pressure

Volume cycled mode Constant volume - Varied Airway pressure with Compliance[Plateau Pr] and Airway resistance [Peak Pr]

Choice as initial ventilation mode in ED

Ventilator pressure act a monitor for Pulm. Compliance

Barotrauma

Pressure cycled mode Inhalation continue till pre-set peak inspiratory pressure attained

Tidal volume vary with pulmonary and thoracic compliance

Decelerating inspiratory flow

Homogenous gas distribution

Pressure cycled mode

Tidal volume changes with pulmonary dynamics

Demands Close monitoring

Limits its use in ED

Dual mode Volume cycled - pressure limited is ideal for

Emergency departments

HFOUltra high respiratory rates [180 to 900breaths per minute]

Tiny tidal volume [1 -4ml /kg]

High airway pressure [25 to 30 mmof H2O]

Useful in Premature infants and ARDS

Limited role in ED

Supports Control mode - Preset volume delivery regardless patient effort, Choice in Apnea , Poor respiratory drive

Support mode -Provides inspiratory assistance through Pressure,Terminate with expiratory pause, Need adequate respiratory drive

“8” Methods of Support

1. CMV

2. ACV

3. IMV

4. SIMV

“8”Methods of Support

1. PSV

2. PEEP

3. CPAP

4. BiPAP

CMV Continous Mandatory Ventilation

Deliver breaths in preset intervals regardless pt efforts

Paralysed /Apneic pts

Increase WOB if pt is having efforts

ACV Assist Control Mode

Deliver preset breaths in coordination with pt efforts

Useful for Pts with intact respiratory efforts

Triggered inspiration

IMV Intermittent Mandatory

VentilationDeliver breaths in preset interval , Preset mandatory volume

Spontaneous breaths in between cause resistance of tubings and valves

Baro trauma

SIMV Synchronous Intermittent

Mandatory Ventilation Deliver preset breaths and volume in coordination with pt respiratory efforts

Limits barotrauma

Disadvantage -increased WOB [Adding PSV will reduce it ]

PSV Pressure support Ventilation

For spontaneously breathing patients

Mode will support every inspiration at preset pressure levels

Airway pressure will maintain till the cut off level reaches

Limits barotrauma

Decrease WOB

Pt decide RR,VT and Flow rate

Pearls ACV/SIMV with full support is the choice in patients require high MV

Reduces Oxygen consumption and carbon dioxide production

ACV in Obstructive airway diseases causes air trapping and Breath staking

Full support ventilation with paralysis ACV=SIMV

PSV is the choice in Pts with adequate respiratory drive

PSV- better pt outcome ,reduced CVS effects ,Less Barotrauma and better gas distribution

Non Invasive ventilationMost commonly used in Ed

Most useful Less complications

NIV Biphasic Positive Airway Pressure

[BiPAP]Ventilatory support though mask in place of ETT

Very useful in mild to moderate respiratory failure

Pt must be mentally alert

BiPAP is not pressure support.

Form of CPAP-alternates high and low positive airway pressures

NIV 4-Indications

Acute exacerbations -COPD

Acute exacerbations -Asthma

Decompensated CHF with mild to moderate pulmonary oedema

Hypervolemic pulmonary oedema

NIV Recommended as an adjunct to Standard

medical therapy [4 clinical scenarios ]

Severe COPD exacerbations[PH,7.35,Relative hypercarbia]

Cariogenic Pulmonary oedema

Respiratory failure with out shock

ACS for urgent PCTA

How do I set ventilator in Ed?Guideline for initial setting

and Special clinical situations

Set “8”parameters

Mode of ventilation

Tidal volume -TV

Respiratory rate -RR

Fractional inspiratory concentration of Oxygen-FiO2

Set “8” parameters

Inspiration/Expiration Ratio

Inspiratory flow rate

Positive End Expiratory Pressure-PEEP

Sensitivity

Mode Based on the need of the patients

Need to order quickly in ED

SIMV and ACV are best modes for initial setting

PSV - for pts with good respiratory drive

Tidal Volume IPPV -10ml/ Kg

Spontaneous breaths 7ml/kg

Obstructive airway diseases and ARDS- 5 -8 ml/kg [ Target to maintain plateau pressure <35cm of water

Respiratory rate

8-12 per minute for Pts not requiring hyperventilation

5-6 per minute is enough for Asthma Pts

Permissive hypercapnia in Asthma is acceptable

“4”Reasons not to set high RR in obstructive airway diseases

Less time for exhalation

increase mean airway pressure

Air trapping

Hypotension

FiO2

Lowest FiO2 to get SaO2<90% and PaO2>60 mm of Hg

A FiO2 of 0.4 is acceptable

Inspiration/Expiration ratio [I/E]

I/E to start with 1:2

Obstructive airway disease 1:4 or 1:5[To avoid air trapping and auto PEEP]

ARDS - 2:1[Inverse ratio]

Inspiratory Flow rateIFR is a function of TV,I/E and RR

Controlled by these parameters

Typical setting 60L/mt

Obstructive airway disease up to 100L/mt

PEEP Positive End Expiratory Pressure

Beneficial if used optimally with low tidal volume

Decreases ventilator induced lung injury

Reduce atelectasis trauma

Minimise trauma due to cyclical collapse and reopening


Shift lung water from alveolar space to perivascular interstitial space

Provide acceptable O2 level & Reduce FiO2 to non toxic level [0.5]

PEEP must be balanced with excessive intra thoracic pressures


“4” indications ARDS

Cariogenic Pulmonary oedema

Non cariogenic Pulmonary Oedema

Congestive heart failure


“8” adverse effectsIncreased intra thoracic pressure

Decreased Preload

Decreased cardiac out put

Hypotension

Dead space ventilation

Barotrauma

Increased ICP

Tension Pneumothorax


Setting start with 3-5 cm of H2O

Titrate against FiO2

FiO2 target less than 0.5 and PaO2 >60mm of Hg

Sensitivity Assist ventilation [ -1 to -2cm of H2O

iPEEP increases the difficulty to generate a negative inspiratory force

New Gen ventilators senses flow instead of negative pressure - Flow by Mode

Flow sensing decreases WOB

How do I monitor a patient on ventilator

Titrate parameters setting against clinical outcome and safe target values

Monitor “8” parameters in pts on ventilator

Heart rate

Blood pressure

Oximetry

ETCO2

ABG/VBG

Peak inspiratory pressure

Plateau Pressure

Exhaled tidal volume

Monitoring pt on Ventilator

Stable patient - Titrate FiO2 to Minimum using SpO2 or SaO2 as guide

ABG A baseline value and repeat 30 mts after a major change in the setting

PaCO2 is the indicator of ventilatory function.

PIP &PP reflects Ventilatory dysfunction and lung compliance

Exhaled volume to detect leaks and disconnect

SpO2 and ETCO2SpO2 reflect beat to beat oxygenation status ETCO2 reflect breath to breath ventilation status

ETCO2 detects

Ventilation status

Detects ventilator dysfunction

ETT obstruction

Tube dislodgement

Fight with ventilator

What are the consequences ?Cautions and Precautions

Adverse consequences of Mechanical ventilationSystemic inflammatory effects and biochemical pulmonary injury

Barotrauma and volutrauma

High FiO2 related free radical lung injury - Atelectasis and shunt

Dead space ventilation

Adverse consequences of Mechanical ventilationBacterial translocation and Bacteremia

Increased Intra thoracic pressure ,decreased venous return and COP, RV and LV dysfunction

Hypotension

Adverse consequences of Mechanical ventilationDecline in renal function

Increased hepatic vascular resistance and bile duct pressure

Gastric mucosal ischemia and GI bleed

Trouble shooting in ventilation How do I manage complications in the ED ?

Clinically deteriorating Mechanically ventilated Pt

EET/Ventilator dysfunction

Improper Ventilator settings

Pain

Anxiety

Pulmonary or Extra Pulmonary disease process

“4” most common presentations of ventilator trouble shoots in the ED

1. Hypoxia

2. Hypotension

3. High pressure alarms

4. Low exhaled volume alarms

Intubated and ventilator patient with Heamodynamic and respiratory instability …

Disconnect from ventilator

Initiate manual ventilation

Set 100% oxygen

Look for DOPE

Displacement -Obstruction-Pneumothorax-Equipment failure

Displacement -ETT

Obstruction - ET Tube and Tubings

Pneumothorax -Tension

Equipment failure

DOPE

“4” reasons for Cardio-Respiratory instability in Pts on ventilators

1. Tension Pneumothorax

2. Intrinsic PEEP

3. Obstructed Tube

4. ETT cuff leak

Tension Pneumothorax

Needle decompression

Tube thoracotomy

Clinical diagnosis

Should wait for Chest radiograph

Intrinsic PEEP

Asthma & COPD patients

Incomplete exhalation and hyper inflation

Confirmation - Perform an End expiratory Hold or Non zero End expiratory flow on ventilator

Intrinsic PEEP

Allow lung deflation

Change setting by longer expiratory timings

Decrease RR ,Decrease TV or Change I/E Ratio

Obstructed tube Significant airway resistance

High pressure alarms

Extrinsic compression,Tube plugs and Mucus,Blood ,FB, Kinks and Bites

Suction and Sedation

PIP and Pplat helps to locate resistance

PIP = resistance to air flow [measured by ventilator ]

Plato = pulmonary compliance [measured by a brief inspiratory pause ]

PIP and Pplat locate resistance

High PIP +Normal Pplat= Increased resistance to flow [ETT obstruction or Bronchospasm]

High PIP +High Pplat= Decreased lung compliance [Pneumonia,ARDS,Pulmonary Oedema,Abdominal distension]

“8” causes for High pressure PIP and Pplat

High pressure alarm? “8”Causes

1. Worsening ARDS

2. Pneumothorax

3. Endobrochial Intubation

4. Tube Bite and Block

5. Pulmonary oedema

6. Chest wall rigidity

7. Increased Intra abdominal pressure

8. Psychomotor agitation

Low exhaled volume Alarm

Air leak

Ventilatory Tube disconnection

Balloon deflation

Tracheal tube dislodgement

Treat- Tube placement ,Ballon inflation& Reconnect to ventilator

“8” causes for Hypoxia

following intubation and Mechanical ventilation

1. Secondary to hypoventilation

2. Worsening cardiac shunting

3. Inadequate FiO2

4. Main stem intubation

5. Aspiration

6. Tube dislodgement

7. Pulmonary Oedema

8. Wrong gas- compressed air or Nitrous oxide

Hypoxia following intubation and Mechanical ventilation

Increase Oxygen -FiO2

Change ventilator setting

Increase PEEP ,RR

Exclude DOPE

Hypotension following intubation and Mechanical ventilation

Decreased venous return and Increased Intrathorvacic pressure

Vasovagal reaction to intubation

RSI

Sedation

Tension pneumothorax

Hypoxia following intubation and Mechanical ventilation

IV fluids

Change Ventilatory setting

Reduce PEEP

Reduce VT and RR

Supportive care Anticipatory …

how to reduce morbidity and mortality

How does ED physician responsible for secondary complication

Traditionally limited to Intubation and Initiation of ventilation

Long ED stay is due to non availability of ICU beds

EP should initiate preventive measures to decrease secondary complications

Secondary complications

Ventilator associated pneumonia -VAP

Venous thromboembolism -VTE

Stress Related Mucosal injury

VAP

Most common infectious complication

Prolonged ICU & Hospital stay

Prolonged Ventilator days

Increases cost of care

VAP ED related independent risk factors

Pre-hospital intubation

ED intubation

ED length of stay

ED level measures to decrease VAP

Due to Aspiration and bacterial colonisation

Semi upright position -3o to 45 degree head end elevation

NG Tube

Oral care with soft tooth brush

Chlorhexidine rinses

Cuff pressure monitoring 4 hourly [20 to 30cm of H2O

VTE

VTE prophylaxis from ED

Unfractionated Heparin

Low molecular weight Heparin

Stress related GI mucosal injury

75% ICU patients develops SRGIM injury within 24 hours

Proton pump inhibitors

Sucralfate

Histamine receptor antagonist

Identify high risk patients to develop Stress induced GI injuries

High risk patients Coagulopathy

GI bleeds

Gastritis

Peptic ulcer

Mechanical ventilation more than 48 hours

Summary EP has to initiate mechanical ventilation in critical scenarios

EP should know basics and beyond

ED based mechanical ventilation strategy is different

Close monitoring and targeted titration is essential to bring successful outcome

EP has pivotal role in preventive care in ICU complications

Core reference article

Thank you so much critically

yours dr.venu

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