Mechanical ventilation is an important life-saving intervention for extremely premature and sick newborns. While it supports oxygenation and carbon dioxide removal, it can also cause lung injury if not optimized. The document discusses the physiology of ventilation, components of mechanical ventilators like pressures and volumes, basic ventilation modes, and pulmonary graphics. Modes like volume guarantee aim to balance supporting gas exchange while limiting volumes and pressures. Understanding ventilation principles, ventilator operations, and individualizing strategies are important for achieving optimal outcomes for mechanically ventilated newborns.

1. Dr. Asaduzzaman
Resident:Year-5
Department of Neonatology,
Bangabandhu Sheikh Mujib Medical University.

2. Mechanical Ventilation in
Newborn:
Modes and Graphics

3. Overviews :
Mechanical ventilation is an extraordinary life-
saving intervention for:
• Extremely low birth weight infants.
• sick neonates with respiratory failure.
29 weeks or 1000 g
Delivery room intubation 56%
Mechanically ventilated in the first 3 days of life
75%
Source: Neonatal research network.2018

4. Overviews :
Mechanical ventilation is associated with many
adverse effects.
Despite of increasing uses of noninvasive ventilation
MV reserve for most immature and sickest infants .
• Ventilator induced lung injury
• Bronchopulmonary dysplasia
• Air leak syndrome

5. Overviews :
In Our NICU 9%
baby underwent
mechanical
ventilator.
Among them
survival rate was
only 18%.

6. Int J Med Res Prof.2020 Jan; 6(1); 100-06

7. Overviews
:

8. Overviews :
As the survival rate is still poor ……..
So, Optimal outcome must achieve by:
1. Thorough understanding respiratory physiology.
2. Operating principles of ventilators.
3. Patient’s specific strategies.

9. Outlines of the presentation:
Basic physiologic principles
Overview of mechanical
ventilators
Basic modes of ventilators
Graphics and
loops

10. Lung volume and Capacities
Lung volumes
1. Inspiratory reserve volume
2. Tidal volume
3. Expiratory reserve volume
4. Residual volume
Lung capacities
1. Vital capacity
2Inspiratory capacity
3. Functional residual capacity
4. Total lung capacity

11. Lung
Volumes
and
Capacities

12. Basics
Oxygenation
*Increasing PAO2 via increasing (FiO2)
*Increasing the surface area for gas exchange by increasing
mean airway pressure & optimizing lung volume.
*Maximizing pulmonary blood flow.
Optimizing ventilation (V)-to-perfusion (Q).

13. Basics
Ventilation (V) & Perfusion(Q)
• Ventilation is the process of removal of carbon dioxide from the
lungs.
• Perfusion means flow of blood to alveolar capillary .
• Ventilation perfusion mismatch is usually caused by poor
ventilation of alveoli relative to their perfusion.

14. Compliance
• Compliance describes the
elasticity or distensibility of
the lungs & chest wall.
• Compliance = ΔV /ΔP
• ml/cmH2O
• Low Compliance means Stiff
lungs [as in RDS]. It will
need higher pressure
gradient for pushing air
inside.

16. Resistance
• Inherent capacity of the air conducting
system (airways &ETT) & tissues to
resist airflow.
• The pressure gradient required to move
gas through the airways at a constant
flow rate.
• R= P1-P2
V
• R ∝ L
r4
• Depends on
Total cross-sectional area
Lengths of the airways
Flow Type
Density and viscosity of gas

17. Dead space
Anatomic
dead
space
Functional
dead
space
Total dead
space
• In Preterm infants smaller VT values and a higher
rate, especially in RDS.
• This strategy limits work of breathing with a less
compliant lung with RDS and helps to maintain
functional residual capacity (FRC) →this strategy may
increase dead space ventilation and decrease
alveolar minute ventilation, →which determines
arterial PCO2.
Long ET
tube
No gas exchange
Inadequate
perfusion

18. Time constant
• 1 Tc of a respiratory system is
defined as the time required
by the alveoli to fill or empty
63% of its tidal volume .
• Tc = C x Raw
• Stiff alveoli (RDS) have very
short Tc, so small Ti is
sufficient to fill them so they
need faster RR.
• Conditions with high Raw
(e.g.MAS, BPD) have long
Tc, so rate should be lower.

19. Basics
Overview of Mechanical ventilation: Key concepts
Maintain adequate lung volume
• Inspiration: Tidal volume (VT)
• Expiration: End-expiratory lung volume (EELV)
Support oxygenation and CO2 removal
• Oxygenation: Adequate mean airway pressure
• CO2 removal: Adequate minute ventilation
Optimize lung mechanical function
• Compliance
• Resistance
• Time constant

20. Ventilation Modes

21. Important ventilator parameter
Oxygenatio
n
Fi0₂
MAP ( ↑ PIP,PEEP, Ti,
Flow)
CO2 removal
MV= VtXRR
VT can be ↑ by
↑ PIP, ↑RR
MV
PIP
PEEP
MAP
Rate
Ti
FiO2

22. Pressures in Mechanical
Ventilator
Peak Inspiratory
pressure (PIP)
• Maximum pressure
during inspiration.
Positive End Expiratory
Pressure (PEEP)
• Pressure present in
the airways at the
end of expiration.
Mean Airway Pressure
(MAP)
• Average pressure
exerted on the airway
and lungs from the
beginning of
inspiration until the
beginning of the next
inspiration.
PIP PIP
PEEP PEEP
MAP = (PIP – PEEP)(Ti) + PEEP
(Ti+Te)

23. How ventilator display PIP

24. Pressures in Mechanical
Ventilator
• ↑MAP
• ↑PaO2
• ↑CO2 elimination.
• ↑Risk of air leak syndrome
↑PIP
• ↑ FRC
• ↑ PaO2
• ↑ MAP.
• ↓Tidal volume
• ↓ CO2 elimination
• ↑Risk of air leak syndrome
↑PEEP

25. Tidal volume & Minute Ventilation
Tidal volume (VT)
• Amount of inspired gas during single
mechanical inflation.
• Approximately 4-6 ml/kg.
Minute ventilation
• Total ventilation per minute
• MV= VT X Rate
• Approximately 240-360 ml/kg/min

26. Ways to increase mean airway pressure
MAP
Flow
I:E
PEEP PIP
↑PaO2,
↓PaCO2
higher
rate

27. Other Ventilator
Parameters
Rate
• ↑Rate →↑MV → ↑ CO2 elimination.
• ↑↑ Rates → Insufficient Ti → low TV;
• ↑↑ Rates → insufficient Te → air trapping
Ti
• Normal 0.3 – .5 sec; affects I:E ratio; I:E ratio is usually 1.15 to 1.3;
• ↑I:E ratio →↑ MAP →↑oxygenation
FiO2
• Increases oxygenation
• Prolonged high FiO2 may lead to oxygen toxicity.
Flow
• Rate of volume delivery, Usually started at flow of 4 – 8 L/min, minimum
2 times of Minute ventilation.
• Inadequate flow : air hunger, asynchrony & increased work of breathing.
• Excess flow : turbulence, hyperinflation, volutrauma, inefficient gas
exchange & Inadvertent PEEP.

28. Mechanical Ventilation Phases
Inspiration
ends &
Expiration
starts
(CYCLE)
Expiration
ends
(BASELINE
PRESSURE)
Inspiratio
n Starts
(TRIGGER
POINT)
Maximu
m
Inspirati
on
(LIMIT)

29. Control of Mechanical breath
Parameter Types
1. Initiation of breath
(Triggering)
Time trigger
Patient trigger (Flow trigger,
Pressure trigger,
Eadi)
2. Pattern of
inspiratory flow Constant flow
Decelerating flow
3. Mechanism for
limiting
the
breath (Size of breath)
Volume controlled
Pressure controlled
4. Termination of breath
(Cycle) Time cycle
Flow cycle

30. Time cycled Pressure Limit Ventilation (TCPLV)

31. Basic Modes of ventilation

32. Ventilation Modes
Asynchronized
Controlled mechanical
ventilation (CMV)/
Intermittent Mandatory
Ventilation (IMV)
Synchronized
Assist control (AC) /
Synchronized Intermittent positive pressure Ventilation (SIPPV)
Synchronized Intermittent Mandatory Ventilation(SIMV)
Pressure Support (PS)
SIMV + PS

33. IMV/CMV Assist Control
Trigger None (Ventilator) Every breath
Cycle Time Time
Ventilator rate Set by user Driven by baby+Backup
rate
Tidal volume Variable Relatively stable
Work of breathing High Lowest
Weaning Decreased rate & PIP Decreased PIP, Leave
rate same

34. SIMV SIMV+ Pressure support
Trigger Set number of breaths Every breath but different
support
Cycle Time Time/Flow
Ventilator rate Set by user Set by user+PS ratedriven
by baby
Tidal volume Variable Less variable but two
patterns
Work of breathing High/depends on rate Variably decreased,depends
on PS level
Weaning Decreased rate & PIP Decreased SIMV rate,&
PIP,continue PS

35. Controlled Mechanical Ventilation & Assist
Control Mode
CMV/ IMV
• All breaths are initiated and delivered by the ventilator.
• Delivers preselected ventilator rate
• Used in Transport ventilators and in Operating room
• No synchronization
AC/ SIPPV
• Allows the patient to initiate ventilator breath
• Patient effort is assisted by ventilator
• If patient has inadequate breath to initiate, ventilator
breaths will be delivered by at a preselected rate
• All breaths once triggered (patient/time) are treated as
same and have a constant VT and PIP

36. Controlled Mechanical Ventilation & Assist
Control Mode

39. Synchronized Intermittent Mandatory Ventilation
(SIMV)
• Ventilator will deliver a breath in response to patient trigger.
• If no trigger is sensed, ventilator will deliver a mandatory breaths at
preselected rate.
• Patient is allowed to breath spontaneously in between mandatory breaths.
• PS can be added to support spontaneous breath.
Spontaneous breaths in excess of the set ventilator rate are not
supported.
Preferable mode for spontaneously breathing infants

41. Assist Control & SIMV

42. Pressure Support Ventilation
Every breath must be triggered by patient and
supported by set amount of pressure
No mandatory breath
Usually added in SIMV to support spontaneous breath
(To overcome the resistance of endotracheal tube and
thereby reduces work of breathing)

44. SIMV+ PSA

45. Volume - Targeted
Targeted to maintain a user selected tidal volume
Pressure controlled ventilation
Time or flow cycled
Automatic adjustment of inflation pressure
Can be used combined with any basic modes of mechanical ventilation

46. 1.The set tidal volume is achieved with the working pressure in (a).
2.The set tidal volume is not achieved with the second breath (b);
3.this resulted in an increased pressure required (within the maximum PIP set) to achieve the desired tidal volume
in the third breath (c)
4. The increased tidal volume with increased pressure (d)
5.resulting in subsequent reduced pressure and targeted tidal volume achieved with last breath (e)
The pressure increment limit is 3 cm H20
which prevents over correction.
Volume guarantee

47. Volume guarantee

48. Initiation of Ventilator support:
Indications
Inadequate or absent
respiratory effort
Absent, weak, or intermittent spontaneous effort
Frequent (>6 events/hour) or severe apnea requiring PPV
Excessive work of breathing
(relative)
Marked retractions, severe tachypnea, >90–100/min
High oxygen requirement FiO2 > 0.40–0.60; labile SpO2 if PPHN is suspected
Severe respiratory
acidosis
pH <7.2 and not improving, PCO2 >65 on days 0–3, >70
beyond day 3
Moderate or severe respiratory
distress and contraindications
For NIV support
Intestinal obstruction; intestinal perforation; recent
gastrointestinal surgery; ileus; CDH
Postoperative period
Residual effect of anesthetic agents; fresh abdominal
incision; need for continued muscle relaxation (e.g.,
fresh tracheostomy)
Goldsmith’s
Assisted
ventilation of
the Newborn,
7th edition

49. Indications
Relative indication:
1. Administration of Surfactant
2. Frequent intermittent apnoea unresponsive to drug
3. Relieving increase work of breathing in infants with
moderate to severe respiratory distress
4. Early intervention with mechanical ventilation
Management protocol of newborn,
NICU, BSMMU, January 2016

50. Choosing ventilator mode
Control variables
• Pressure controlled ( preferred in neonates)
• Volume controlled
With volume targeting (More recent modification)
Start with
If adequate self
breath
During weaning
To see the
spontaneous Tv
Before
Extubation
AC
SIMV
Pressur
e
Support

51. • Authors' conclusions
Infants ventilated using VTV modes had reduced rates of
death or BPD, pneumothoraces, hypocarbia, severe
cranial ultrasound pathologies and duration of ventilation
compared with infants ventilated using PLV modes.
Volume Guarantee: Pressure controlled, volume targeted, flow or
time cycled

52. Pulmonary Graphics
Graphical representation of Pressure, Flow and Volume.
A. Scalar Waveforms: 1. Pressure-time
2. Flow- time
3. Volume- time
B. Loops: 1. Pressure-Volume loop
2. Flow-Volume loop

53. Pressure Limit waveforms

54. Volume Limit waveform

55. Volume Limit vs Pressure limit
waveform

56. Abnormal volume wave form:
Air leak

57. Abnormal flow wave form
Too shot Ti
Inspiratory obstruction
Too small ET tube

58. Abnormal flow wave form
Too shot Te
Expiratory obstruction
Bronchospasm
Too small ET tube
Air trap/ Auto PEEP

59. Abnormal wave form
Secretion
Water in circuit
Ventilator malfunction

60. Abnormal Pressure wave
form
Ppeak ∝ Resistance
Pplat ∝ 1
.
Compliance

61. Adequac
y
Loops in mechanical ventilator

64. Normal Pressure-Volume Loops
PEEP: Positive end
expiratory pressure.
PIP/Ppeak: Peak
inspiratory pressure.
TV: Tidal volume.
Peak Palv: Peak alveolar
pressure.
Pta: Trans airway pressure.
Opening pressure:
Increasing lung volume with
minimal change in pressure.
Closing pressure: Minimal
PEEP

65. Pressure-Volume Loops: Controlled vs
Assisted Breath

66. Pressure volume loops: lung compliance
change

67. Abnormal pressure-volume Loops:
Overdistension
Pressure
overshoot:
Bird beak

68. Abnormal pressure-volume Loops:
Resistance
• Small size ET tube
• ET tube kinking/biting
• Secretion
• Mechanical
obstruction of airway
Inspirator
y
resistance
• Secretion
• Bronchospasm
• Mechanical
obstruction of airway
Expiratory
resistance

69. Abnormal pressure-volume Loops:
Air Leak

70. Normal Flow-Volume Loop

71. Adequac
y
Abnormal Flow-Volume Loop: Air
leak

72. Basics
Adequac
y
Abnormal Flow-Volume Loop: Auto-
PEEP

73. Basics
Adequac
y
Abnormal Flow-Volume Loop: Decreased
peak flow
Obstruction
Secretion
Bronchospasm

75. Adequac
y
Abnormal Flow-Volume Loop: Abnormal flow
Secretion/ Water in
Inspiratory/ Expiratory
limb

76. Abnormal Flow-Volume Loops abnormal flow

77. Dräger Evita®
Infinity® V500
ventilator
ICU Ventilation
and Respiratory
Monitoring
Evita infinity V600/800
The latest generation Dragger Evita series

78. DRÄGER BABYLOG®
VN500
Dräger Babylog VN500 ventilator

79. Thank you