INTUBATION AND VENTILATION : Emergency Learning

INTUBATION AND VENTILATION

Contents

Preparation

Procedure

Tip&Tricks

Securing ETTube

Suction of ETTube

Preparation...

Intubation - Elective or Emergency

Elective: for patients undergoing GA

Emergency indications

Rapid Sequence Induction

The Essentials...

Monitoring - SPO2, BP, PR, ECG (Cardiac monitor)

Glove, Mask

Oxygen Source

Ambu-bag with mask/GA Machine/Endotracheal Tube/Laryngoscope/Different blade size (Mac 3-4 adult/Mac 2 for paediatrics). McCoy blade/Bougie if anticipated difficult airway/Glidescope

Drugs: Resuscitation, Opioid, Induction agent, Relaxants

make sure...

Oxygen source: wall, tank, GA Machine

Suction: Yaunker and suction tube, suction apparatus functioning

Airways: oropharyngeal airway or nasopharyngeal airway

Laryngoscope with functioning light bulb

Endotracheal tube of approriate sizes(7.5/8 for male, 7-7.5for female, 6.5-7 for gravid women/ Age/4 +4 for children with one size smaller and bigger as standby)

Lubricating jelly, Syringe 10-20mls

Good assistants

Tip and Tricks

Securing ETT

plaster - trouser like

string tie

Reason-risk of dislodgement

Male-20-23cm

Female-18-21cm

Paediatric-Age/2+12

Airway Physical Exam

Assessment of possibility of difficult airway;

Obesity

Short Neck

Large tongue

Loose teeth/Buck teeth

Poor mouth opening-<2fb p="">

Limited neck movement

Beard

Receding chin/Small chin

The 4Ds of Difficult Intubation

Distortion: laryngeal oedema, blood, vomitus, tumour mass, abscess

Dysmobility of joints: TMJ, atlanto occipital, suspected cervical trauma on hard collar

Disproportion: thyromental distance <6cm mallampati="" p="" scoring="">

Dentition: buck teeth

Mallampati Classes

Class 1: Faucillar pillars, soft palate, uvula

Class 2: Faucillar pillars, soft palate

Class 3: Soft palate

Class 4: Soft palate not seen

Positioning during intubation

Positioning...

Cricoid Pressure

How to perform intubation

Endotracheal Suctioning...

Importance

The proper method

Type of endotracheal suctioning - Open, Closed

Setting Ventilator... the basic

Contents

History

Basic Physiology

Pressure Control

Volume Control

Ventilators...

History...

“ … an opening must be attempted in the trunk of the trachea, into which a tube of reed or cane should be put; you will then blow into this, so that the lung may rise again … and the heart becomes strong…”

                                                 Andreas Vesalius (1555)

First description of positive pressure ventilation.

Took 400 years to apply on patient care.

Respiratory System...

a balloon connected to a tube

balloon = elastic element                  (lungs and chest wall)

tube = the resistive element (conducting airways)

Ventilation Simplified

Respiratory Pump = Mechanical Ventilator

Generate sufficient pressure to overcome both the resistance and compliance of the lung to allow gas exchange between the environment and the pulmonary capillary bed

Indications for Mechanical Ventilation

inadequate ventilation to maintain pH(raised CO2)

inadequate oxygenation

excessive breathing workload

congestive failure

circulatory shock

Goals of Mechanical Ventilation

Maintain appropriate levels of partial pressure of O2 and CO2 in arterial blood

Unload/reduce the workload of the ventilatory muscles

Protect the lung from overdistention and recruitment-derecruitment injury

Main Determinants

Mean Airway Pressure

refers to the mean pressure across the entire respiratory cycle, both inspiration and expiration

The most obvious method of increasing the pressure is to increase the tidal volume, this also will increase the PEAK and PLATEAU airway pressure. High risk of ventilator induced lung injury

Prolonging the Inspiratory Time increase the mean pressure

Inspiratory Time

Set as

% of respiratory cycle

I:E ratio

Expiratory time not set

remaining time after inspiration before next breathing

Increased inspiratory time

improved oxygenation

unnatural

increase risk of gas trapping

PEEP

-Increasing the FRC

-Re-inflating atelectatic lung areas and recruitment of collapsed alveoli

-Optimizing the V/Q ratio

-Reducing the right-left shunt

-Avoiding end expiratory alveolar collapse

Standard Parameter

Following settings are for all patients admitted into ICU for mechanical ventilation unless stated otherwise by doctor in charge of ICU

Mode: SIMV (Volume) or SIMV (Pressure 10-20)

Rate: 8-12 breaths/min

Tidal Volume(amount of air delivered for each breath: 6-10mls/kg

PBW Males= 50 + 2.3 [height (inches) - 60]

Females= 45.5 + 2.3 [height (inches) -60]

Start with fiO2 1.0 and titrate down with serial ABGs

Oxygen toxicity (eg. pulmonary fibrosis) does not usually occur if a FiO₂ of 1.0 is used for < 24 hours.

 The goal is to keep PaO₂ within 83-100 mmHg or SaO₂ within > 92% (try to avoid FiO₂ > 60%)

FiO₂ requirement can further be reduced by adding PEEP (positive end-expiratory pressure)

PEEP                                 :           5 - 20 cmH₂O.

 As a result, FiO2 can be kept at a minimum to avoid oxygen toxicity.

 In some situations higher levels of PEEP may be required but unless indicated levels of 5cmH2O is deem adequate.

FiO₂/PEEP Combination

Pressure Support

10cmH₂0

Helps decrease patient's work of breathing.

 A level of 10cmH₂O is deem necessary to overcome the ventilator circuit resistance (e.g. the demand valves that are triggered open with each breath, and the resistance of breathing through the small diameter of the endotracheal tube).

 Adequacy of pressure support (PS) can actually be gauge by increasing PS by 1 - 2 cmH₂O while assessing patient comfort and  RR < 30 or normal TV (500mL) is achieved.

Keep PS < 35 to avoid barotrauma and hemodynamic compromise secondary to a decrease in cardiac output.

Inspiratory:Expiratory

During spontaneous breathing, the normal I:E ratio is 1:2, indicating that for normal patients the exhalation time is about twice as long as inhalation time.

If exhalation time is too short “breath stacking” occurs resulting in an increase in end-expiratory pressure also called auto-PEEP.

Depending on the disease process, such as in ARDS, the I:E ratio can be changed to improve ventilation

Sensitivity - Trigger

When pressure triggering is used, a ventilator-delivered breath is initiated if the demand valve senses a negative airway pressure deflection (generated by the patient trying to initiate a breath) greater than the trigger sensitivity.

When flow-by triggering is used, a continuous flow of gas through the ventilator circuit is monitored. A ventilator-delivered breath is initiated when the return flow is less than the delivered flow, a consequence of the patient's effort to initiate a breath

Peak Flow Rate: 50 LPM, max flow delivered by ventilator during inspiration

Alarm Parameters: +/- 20% set parameters

Humidification: Activate

Ideal Breath Types of Mechanical Ventilation

synchronize with patient’s spontaneous breathing effort

maintain adequate & consistent VT & VE at low airway pressure

responds to rapid changes of pulmonary mechanics or patient’s demand

provide lowest possible work of breathing

Basic Classification:

Control:

Volume Controlled: Volume limited, volume targeted and pressure variable

Pressure Controlled: Pressure limited, pressure targeted and volume variable

Volume Control: Adv

Constant flow rate

Guaranteed tidal volume delivered

Variable peak pressure is dependent on the compliance of the lung

Less atelectasis

Precise control of PaCO2

Volume Control: Disadv

Pressure variable & difficult to control

Resultant high peak pressure: barotrauma, volutrauma, acute lung injury

Uneven distribution of ventilation

Increased muscle workload

Flow rate may not match demand

Pressure Control: Adv

Constant inspiratory pressure

Decelerating variable inspiratory flow rate-improved gas exchange

Improves gas distribution & reduce work of breathing

Better tolerance, less sedation needed

More homogenous ventilation

Reduction of peak pressure and risk of barotraumas

Pressure Control: Disadv

Variable tidal volume sec to changes in lung compliance & resistance-hypoventilation

Potentially excessive tidal volume as compliance improves

SIMV ( Synchronized Intermittent Mandatory Ventilation )

Mandatory breaths are delivered at set rate with VC or PC in synchrony with patient’s inspiratory effort

If no inspiratory effort detected, the ventilator delivers a mandatory breath at the scheduled time.

Between mandatory breath, patient is allowed to breath spontaneously.

Spontaneous breaths – pressure support

CPAP ( Continuous Positive Airway Pressure )

Spontaneous breathing mode: no mandatory breath delivered

Most commonly used mode to evaluate extubation readiness

Trouble Shooting

Patient

Machine