Mechanical ventilation by Amarjeet singh.pptx

Mentors - Dr. Ashish Chawla
Dr. Harpreet Bains
Presentor – Dr. Amarjeet Chhanga Rai
Mechanical Ventilation

 Indication
 Mode
 Variable
 Initiation of mechanical ventilation
 Goal
 Monitoring
 Ventilator alarms and there trouble shooting
 Weaning from ventilator
 Complication

Indications of MV
1.Depressed respiratory drive: This group includes
 drug overdose (narcotic, sedative, alcohol),
 acute spinal cord injury,
 head trauma,
 neurologic disorders (coma, stroke),
 sleep disorders (e.g. sleep apnea) and
 metabolic alkalosis.

2.Excessive ventilatory workload
 acute airflow obstruction, e.g. chronic obstructive pulmonary
disease (COPD), asthma or epiglottitis,
 dead space ventilation (pulmonary embolism and emphysema),
 acute lung injury (ALI), e.g. acute respiratory distress syndrome
(ARDS),
 cardiovascular decompensation [decreased cardiac output,
 ventilation/perfusion (V/Q) mismatch], shock,
 increased metabolic rate (fever),
 drugs and decreased compliance (atelectasis, pneumothorax
and obesity).

3. Ventilatory Pump Failure
 This includes chest trauma (flail chest, tension
pneumothorax),
 Premature birth (idiopathic respiratory distress
syndrome),
 Electrolyte imbalance (hyperkalemia or
hypokalemia) and
 Geriatric patients (muscle fatigue).

Modes
 CMV – Controlled MV
 AC – Assist Control MV
 SIMV – Synchronised Intermittent Mandatory
Ventilation
 PSV – Pressure support Ventilation
 IRV - Inverse ratio ventilation
 HFV - High Frequency ventilation
Others modes of MV
 ASV – Adaptive support Ventilation
 APRV – Airway pressure release Ventilation
 PAV - Proportional assist Ventilation
 BVV - Biologically Variable Ventilation
 NAVA – Naturally Adjusted Ventilatory assist

Variables
 Fraction of inspired oxygen
 Respiratory rate
 Tidal volume
 PEEP
 I:E Ratio
 Pressure support
 Trigger (Pressure/Flow)
 Pressure limit

Inspiratory hold
Expiratory hold
100% FiO2
Accept Mode
Alarms reset
Preset
variables
and alarms
outcomes
Mode

● Fraction of inspired oxygen (FIO2)
 The percent of oxygen concentration that the patient
is receiving from the ventilator. (Between 21% &
100%)
(room air has 21% oxygen content).

Initially a patient is placed on a high level of FIO2
(60% or higher).

Subsequent changes in FIO2 are based on ABGs and
the SaO2.


In adult patients the initial FiO2 may be set at 100% until
arterial blood gases can document adequate oxygenation.

An FiO2 of 100% for an extended period of time can be
dangerous ( oxygen toxicity) but it can protect against
hypoxemia
 For infants, and especially in premature infants, high levels
of FiO2 (>60%) should be avoided.

Usually the FIO2 is adjusted to maintain an SaO2 of greater
than 90% (roughly equivalent to a PaO2 >60 mm Hg).

Oxygen toxicity is a concern when an FIO2 of greater than
60% is required for more than 25 hours

● Tidal Volume (VT)
 The volume of air delivered to a patient during a
ventilator breath.
 The amount of air inspired and expired with each
breath.
 Usual volume selected is between 5 to 15 ml/ kg
body weight)

● Peak Flow/ Flow Rate
 The speed of delivering air per unit of time, and is
expressed in liters per minute.
 The higher the flow rate, the faster peak airway
pressure is reached and the shorter the
inspiration;
 The lower the flow rate, the longer the inspiration.

● Respiratory Rate/ Breath
Rate / Frequency ( F)
 The number of breaths the ventilator will
deliver/minute (10-16 b/m).
 Total respiratory rate equals patient rate plus
ventilator rate.
 The nurse double-checks the functioning of the
ventilator by observing the patient’s respiratory
rate.

For adult patients and older children:-
With COPD
 A reduced tidal volume
 A reduced respiratory rate
For infants and younger children:-
 A small tidal volume
 Higher respiratory rate

● Minute Volume (VE)
 The volume of expired air in one minute .
 Respiratory rate times tidal volume equals minute
ventilation
VE = (VT x F)
 In special cases, hypoventilation or
hyperventilation is desired

● I:E Ratio (Inspiration to
Expiration Ratio):-
 The ratio of inspiratory time to expiratory time
during a breath
(Usually = 1:2)

● Sensitivity(trigger Sensitivity)
 The sensitivity function controls the amount of
patient effort needed to initiate an inspiration
 Increasing the sensitivity (requiring less negative
force) decreases the amount of work the patient
must do to initiate a ventilator breath.
 Decreasing the sensitivity increases the amount of
negative pressure that the patient needs to initiate
inspiration and increases the work of breathing.

Ensuring humidification and thermoregulation
 All air delivered by the ventilator passes through the water
in the humidifier, where it is warmed and saturated.
 Humidifier temperatures should be kept close to body
temperature 35 ºC- 37ºC.
 In some rare instances (severe hypothermia), the air
temperatures can be increased.
 The humidifier should be checked for adequate water levels

1. Controlled Mandatory ventilation
• All breaths are mandatory
• Preset frequency, inspiratory time/Inspiratory flow
• Pressure or volume control
• Trigger: Time
• Limit: Volume, flow or pressure
• Cycle: Time, volume

Volume vs. Pressure Control
Volume Preset
 Set parameter is the tidal
volume; airway pressure is
variable
 Constant tidal volume in the
face of changing lung
characteristics
 Patient-ventilator asynchrony
due to fixed flow rate
 No leak compensation
Pressure Preset
 Set parameter is airway
pressure; tidal volume
delivered is variable
 Tidal volume varies with
changes in lung
characteristics
 Flow will vary according to
patient's demands
 Compensates for leaks

2- Assist Control Mode A/C
 The ventilator provides the patient with a pre-set tidal volume at a
pre-set rate .
 The patient may initiate a breath on his own, but the ventilator
assists by delivering a specified tidal volume to the patient.
 Patient can initiate breaths that are delivered at the preset tidal
volume.
 Client can breathe at a higher rate than the preset number of
breaths/minute

 The total respiratory rate is determined by the
number of spontaneous inspiration initiated by the
patient plus the number of breaths set on the
ventilator.
 In A/C mode, a mandatory (or “control”) rate is
selected.
 If the patient wishes to breathe faster, he or she can
trigger the ventilator and receive a full-volume
breath.

 Often used as initial mode of ventilation
 When the patient is too weak to perform the work
of breathing (e.g., when emerging from anesthesia)
 Advantages -- reduce work of breathing ,Allows
patient to modify minute ventilation by increasing
res. Rate
Disadvantages:
 Hyperventilation, Respiratory Alkalosis
 Patient on ACMV have higher pH and low PaCO2

3. Synchronised intermittent mandatory ventilation
• Synchronised mandatory breaths with spontaneous
breaths allowed in between
• Ventilator creates a time window around the scheduled
delivery of mandatory breath
• If a patient effort is detected, it synchronises the
machine breath with the patient’s inspiration
• If no patient effort is detected, it delivers a breath at
the scheduled time

3 - Synchronized Intermittent
Mandatory Ventilation (SIMV)
 The ventilator provides the patient with a pre-set number of
breaths/minute at a specified tidal volume and FiO2.
 In between the ventilator-delivered breaths, the patient is
able to breathe spontaneously at his own tidal volume and
rate with no assistance from the ventilator.

 The tidal volume of these breaths can vary
drastically from the tidal volume set on the
ventilator, because the tidal volume is determined
by the patient’s spontaneous effort.
 Adding pressure support during spontaneous
breaths can minimize the risk of increased work of
breathing.
 Ventilators breaths are synchronized with the
patient spontaneous breathe.
( no fighting)

Pressure
Flow
Volume
(L/min)
(cm H2O)
(ml)
Time (sec)
SIMV Mode
Spontaneous Breath

4.Pressure Support
 Completely spontaneous mode in which patient
triggers each breath
 On inspiration patient exposed to a preset pressure
 Inspiration is terminated when the flow rate reaches
a minimum level or % of peak flow
 Trigger: Patient
 Limit: Pressure
 Cycling: flow

5. Inverse ratio ventilation (IRV)
 Inverse ratio ventilation (IRV) mode reverses
this ratio so that inspiratory time is equal to,
or longer than, expiratory time (1:1 to 4:1).
 Inverse I:E ratios are used in conjunction
with pressure control to improve
oxygenation by expanding stiff alveoli by
using longer distending times, thereby
providing more opportunity for gas
exchange and preventing alveolar collapse.

6 - High-Frequency Ventilators
 High-frequency ventilators use small tidal
volumes (1 to 3 mL/kg) at frequencies greater
than 100 breaths/minute.
 The high-frequency ventilator accomplishes
oxygenation by the diffusion of oxygen and
carbon dioxide from high to low gradients of
concentration.

 This diffusion movement is increased if the kinetic
energy of the gas molecules is increased.
 A high-frequency ventilator would be used to
achieve lower peak ventilator pressures, thereby
lowering the risk of barotrauma.
 These modes include high-frequency oscillatory
ventilation (HFOV)
 and high-frequency jet ventilation (HFJV).
 It is used more commonly in neonates and
infants with neonatal respiratory failure

Initiating Mechanical Ventilation
 Check ventilator assembly: power connection, circuit
connection, HME filter catheter mount, gas connections
 Switch on ventilator, check on test lung
 Begin Preoxygenation (aerosol precaution)
 Watch for Hypotension
• Infuse Fluids
 Start Mechanical Ventilation
• A/C:TV=350-450, RR=20-30, FIO2= 60-100%
• Peak Flow rate 40-60 l/min
• PEEP=5-10, I:E=1:2, Sens= -0.8 - 2

GOAL
 OXYGENATION GOAL: PaO255-80 mmHg or SpO2 88-95%
 PLATEAU PRESSURE GOAL: ≤ 30 cm H2O
 pH GOAL: 7.30-7.45
 Acidosis Management: (pH < 7.30)
 If pH 7.15-7.30: Increase RR until pH > 7.30 or PaCO2
< 25 (Maximum
set RR = 35).
 If pH < 7.15: Increase RR to 35.
 If pH remains < 7.15, TV may be increased in 1 ml/kg steps until pH >
7.15 (Pplat target of 30 may be exceeded). (Max TV =8, Min TV=4
ml/kg)
 Alkalosis Management: (pH > 7.45) Decrease vent rate if possible.

Monitoring
 Heart rate
 SpO2
 Respiratory rate
 Pattern of respiration and signs of respiratory distress
 Blood pressure
 ETCO2
 Expired tidal volume: equal to set tidal volume (leaks)
 Peak pressure, Plateau pressure (< 30 mm Hg)

Ventilator alarms and troubleshooting
Alarms Priority Causes Steps
Electrical power/ gas
delivery/ Battery
Highest Disconnection of power supply
or oxygen source
Connect the power or
Oxygen source
Low airway pressure High Disconnection or volume leak,
in appropriate alarm setting
Connect ventilator, check
alarm setting
High airway pressure High Obstruction to flow,
pneumothorax and other
compliance problem (fluid
overload/ abdominal
hypertension)
Check for Ppeak and Pplat
(diff <3-5) if both high:
Compliance problem
(pneumothorax etc)
If Ppeak and Pplat (diff>3-
5) : Resistance problem
(tube/circuit block etc):
suction/change tube,
bronchodilator
Low Expired Vt High ETT cuff leak, Circuit leak, leak
from HME filter, leak from ICD
Check/change ETT, Circuit,
HME filter, ICD
High RR
High PEEP
Moderate Blocked
tube/bronchoconstriction
Suction/bonchodilation

Management of other problems
 Hypoxemia: check for disconnection, Increase Fio2,
Call for help, check for tube block, fluid overload,
check air entry, patient ventilator asynchrony
DOPE:
D: Disconnection/ Dislodging
O: Obstruction,
P: Pneumothorax
E: Equipment failure
There may exist multiple problems

Complications of MV
 Airway management related complications
 Hypotension
 Pneumothorax/Subcutaneous emphysema
 Ventilator induced lung injury
 Ventilator associated pneumonia

Criteria for consideration
for Weaning/discontinuation
 Underlying disease stable or improving
 PaO2 / FiO2 > 200
 PEEP < 5-8 cmH2O
 FiO2 < 0.5
 Reliable respiratory drive
 Stable CVS
 Minimal pressors or inotropes
 Absence of myocardial ischemia
 Capable of initiating inspiratory effort

Underlying condition has
Resolved or improved and there is no other condition mandating MV
Daily screening of RS function
Not Ready Ready
MV and
Daily screening
SBT
T-piece or PSV
30min is enough
Tolerated Not tolerated
Gradual Withdrawal
Once-daily T-piece
PSV
Weaning

CARRY HOME MESSAGE
 CoViD-19 patients usually present to ICU with ARDS.
 For ventilating these patients Tidal volume (TV)
should be calculated by 6 ml/kg PBW. (TVmax=8
ml/kg, TVmin=4 ml/kg)
 Ventilating a patient with ARDS: Low TV, High RR,
High PEEP and Plateau pressure < 30 cm H2O.
 One should be aware of monitoring and
troubleshooting of mechanical ventilator.
 Patient should be initiated on Controlled or assist
control mode of MV and once recovers can be
weaned using spontaneous breathing trial.

Mechanical ventilation by Amarjeet singh.pptx

More Related Content

Similar to Mechanical ventilation by Amarjeet singh.pptx

Recently uploaded

Mechanical ventilation by Amarjeet singh.pptx

Editor's Notes