INTUBATION And VENTILATION
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
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 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
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