1. Mechanical ventilation
In the name of GOD
Principles of
Mechanical ventilation

2. Terminology f: rate of breathing Vt: Tidal volume
VA: Alveolar ventilation
VD: dead space = 2.2 ml/ kg
FiO2: fraction of inspired O2
PEEP: Positive End Expiratory Pressure
PASB : Pressure Above Spontaneous Breathing
ASB : Assisted Spontaneous Breathing

3. Basic pulmonary physiology
Air that moves in and out of a patient's lungs per minute that is L/min  Minute volume (MV)
MV =Vt x f
Alveolar ventilation (VA)  in contact with the alveolar-capillary gas exchange interface
VA = (Vt - VD ) x f
Volume-pressure relation: P = V/C

4. Plateau pressure (static pressure)
… is the pressure at the end of inspiration with a short breath hold
It should not be exceed 30 cmH2O
P plateau ~ 1/compliance (P = V/C)
volume = P plateau

5. Pressure-time diagram for volume controlled constant flow ventilation

6. Peak Airway Pressure (dynamic pressure)
…. is pressure during inspiration
So related to both airway resistance and compliance
compliance and/or resistance  P peak
P peak – P plateau < 4 cm H2O (normal gradient)
P peak is a vital sign for mechanically ventilated patients.
P peak < 35 cmH2O

7. Changes in inspiratory airway resistance

8. Paw-peak increased but Plateau pressure unchanged:
1. Tracheal tube obstruction and kinking
2. Airway obstruction from secretions
3. Acute bronchospasm
Rx: Suctioning and Bronchodilators

9. Changes in compliance In this situation P-P gradient is fixid.
increasing compliance → plateau and peak pressures fall
decreasing compliance → plateau and peak pressures rise

10. Paw-peak and Plateau pressure are both increased:
1. Pneumothorax
2. Lobar atelectasis
3. Acute pulmonary edema
4. Worsening pneumonia
5. ARDS
6. COPD with tachypnea and Auto-PEEP
7. Increased abdominal pressure
8. Asynchronous breathing

11. Decreased Paw-peak:
1.Inadequate gas supply, inadvertent change in setting, system air leak, Tubing disconnection, cuff leak, unintended extubation and failure of the ventilator Rx: Manual inflation, listen for leak 2. Hyperventilation: Enough negative intrathoracic pressure to pull air into lungs may drop Paw-Peak

12. Measurements

13. Measurements

14. P –T curve
At the start of inflation, the airway pressure immediately rises because of the resistance to gas flow (A), and at the end of inspiratory gas flow the airway pressure immediately falls by the same pressure (A) to an inflexion point.

15. P/T F/T V/T curves in VCV

17. Increase in Ppeak–Pplat gradient
Increased airway resistance caused
by heat and moisture exchanger (HME)
Patient biting endotracheal tube
Kinked or twisted endotracheal tube
Obstruction of endotracheal tube by secretions, mucus, blood
Bronchospasm
Obstruction of lower airways

18. Schematic of two superimposed pressure-time curves showing a small increase in peak inspiratory pressures (Ppeak) with a greater increase in plateau pressures (Pplat).
This is characteristic of decreased lung compliance

19. Unchanged or decreased Ppeak–Pplat gradient
Pneumonia
Atelectasis
Mucus plugging of one lung
Unilateral intubation
Pneumothorax
Pulmonary edema (noncardiogenic and cardiogenic)
Abdominal distention/pressure

20. Spontaneous Breathing

21. Positive End Expiratory Pressure
… is the pressure at the end of expiration
Serial Elevated PEEP  P plateau and FRC

22. 1- Extrinsic PEEP (applied PEEP by MV)
cm H2O and be started on 5 cm H2O
It improves the oxygenation not CO2 removal
It may be increased 3-5 cmH2O Q min
It has some side effects: biotraumas and hemodynamic compromise
What is the optimal PEEP?
1- increasing PEEP until a complication occurs
2- assessing P plateau

23. Optimal PEEP P-V curve monitoring
Cardiac Output monitoring and Venous Oxygen Saturation
If SmvO2 decreases after PEEP application  Drop C.O.
In this situation  PEEP and/or tidal volume

24. P-V curve
Adequate PEEP
Inadequate PEEP

25. PEEP

26. PEEP Disadvantages: 1. Decrease BP & CPP 2. Increase PCO2
3. because alveolar injury is often heterogeneous, appropriate PEEP in one region may be suboptimal in another and excessive in another

27. 2- Intrinsic PEEP
…is incomplete alveolar emptying during expiration due to air trapping
Ventilator Factors: High inflation volumes, rapid rate, low exhalation time
Disease factors: Asthma, COPD (collapsed airway)
And has some effects:
Decreased C.O.
Alveolar rupture
increased work of breathing

28. Int. PEEP Int. PEEP may be detected in two ways:
(1) evaluating the flow-time trace (exp. Flow not returned to zero before next breath)
(2) disconnecting the patient from the ventilator and listening for additional exhaled gas after an exhalation has occurred.

29. Pressure cycled
Volume cycled

30. Indications for mechanical ventilation

31. Loss airway protection
No absolute contraindications
Loss of airway anatomy
Loss airway protection
Respiratory and cardiac Failure
Apnea / Respiratory Arrest
Inadequate ventilation (acute vs. chronic)
Inadequate oxygenation
Eliminate work of breathing
Reduce oxygen consumption
Neurologic dysfunction
Central hypoventilation/ frequent apnea
Comatose patient, GCS < 8
Inability to protect airway

32. Control Mechanisms

33. Control mechanisms Spontaneous breathing (PSV)
Pressure targeted ventilation
Volume targeted ventilation

34. 1. Spontaneous breathing:
Setting: FiO2 and PEEP
Flow and f is dictated by patient

35. 2. Pressure-Cycled (targeted):
Alters gas flow and volume  fixed preset airway pressure (Paw) for the duration of a preset inspiratory time (Ti )
Advantage: fixed pressure  limit or eliminate alveolar over-distention and barotraumas
One problem: changes in compliance or resistance with fixed Paw  variable received volume

36. 3 . Volume/ Flow-Cycled (targeted)
Deliver a preset volume of gas ( VT)  Paw is variable
Advantage: delivery a constant VT
changes in compliance or resistance with fixed volume  changes airway pressure

37. There are no clinical outcome studies showing benefit of one breath-targeting strategy over the other.
Pressure-targeting provide a variable flow tends to synchronize better with patient effort.

38. Modes

39. 1. Controlled Mechanical Ventilation /Assist Control (CMV/AC) 2
1. Controlled Mechanical Ventilation /Assist Control (CMV/AC) 2. Intermittent Mechanical Ventilation (IMV)/Synchronized IMV (SIMV). 3. Continuous Positive Airway Pressure (CPAP) /pressure support ventilation (PSV)

40. Controlled Mechanical Ventilation (CMV)
Assist Control (AC)

41. Control Mode Ventilation Continuous mandatory ventilation
Continuous mechanical ventilation
Controlled mandatory ventilation
Intermittent Positive Pressure Ventilation (Dräger)
…is a full support mode (machine breaths)
All breaths are supported regardless of initiation of breathing and can be set to VCV and PCV
Used for: apneic patients, respiratory muscle weakness and LV dysfunction

42. (CMV/AC )
Sensitivity pressure  0.5 to 2 cm H2O (1-3 cm H2O Tintinalli)
The higher sensitivity  the greater work of breathing
After spontaneous breath  the ventilator`s timer resets from this time

43. (CMV /AC)
CMV  preferred and most commonly used initial mode for acute phase of respiratory failure in ED
but CMV :
1. Poor toleration in awake patients
2. Worsening of volume retention in COPD / asthma

44. A/C mode

45. 2. Intermittent Mechanical Ventilation (IMV)
Synchronized IMV (SIMV)

46. SIMV (Dräger, Hamilton)
SIMV (VC) + PS (Maquet)
VCV-SIMV (Puritan-Bennett, Respironics)
Volume SIMV (Viasys)
Intermittent demand ventilation
IMV  combination of spontaneous vent. and AC
IMV  is a partial support mode
This ventilator mode provides breaths at a preset rate (machine breath) similar to the AC mode
Can be set to PCV and VCV

47. (IMV / SIMV )
But in spontaneous breath  only receive a spontaneous VT with no support from the ventilator and has a high work of breathing
The synchronized version of IMV  coordination spontaneous and machine breaths
SIMV:
1. To prevent excess VT delivered (stacking)  decreased hyperinflation, barotrauma
2. During exhalation from a spontaneous breath exhalation compromised

50. 3. Continuous Positive Airway Pressure (CPAP)
pressure support ventilation (PSV)

51. Is a partial support mode
Assisted Spontaneous Breathing(Dräger)
Spontaneous mode(Hamilton, Puritan-Bennett)
Pressure support (Maquet)
CPAP (Respironic)
Pressure Support Ventilation (Viasys)
continuous positive-pressure breathing (CPPB )
EPAP
Is a partial support mode
Breathing control by the patient (spontaneous mode ) , and peak Paw control by machine (pressure targeted)

52. PSV

53. PSV / ASB / CPAP
Help the patient overcome the resistance of the circuit  decreased work of breathing
This is not useful in apnea

54. CPAP / PSV / ASB
CPAP  the least amount of support and used with IPPV or NIPPV
Most commonly used in (COPD) , CHF and obstructive sleep apnea with NIPPV ( via a tight-fitting nasal or full face-mask)

55. CPAP / PSV / ASB With IPPV  CPAP is typically used as a weaning mode
The CPAP level when transitioning from IMV/PSV or AC mode should be the PEEP level that was being used
Reducing the CPAP below the previous PEEP :
Loss of alveolar recruitment
Atelectasis
Hypoxia
Increased work of breathing

56. CPAP / PSV In partial support:
CPAP range is from 0 up to 35 cm H20 pressure
Some ventilators may deliver PSV that achieves a greater range.
The average starting point is:
10 cm H20
Use PSV for approximation of spontaneous Vt and the set Vt for mandatory breaths

57. (CPAP) benefits Eliminate the work of breathing
To aid in weaning from IMV-base ventilation and is frequently part of a transition strategy from IMV to CPAP

58. Breath type & examples

59. DRÄGER Evita CMV

60. DRÄGER Evita CMV

61. DRÄGER Evita SIMV

62. DRÄGER Evita SIMV

63. DRÄGER Evita 2 CPAP

64. DRÄGER Evita CPAP

65. DRÄGER Evita PCV

66. DRÄGER Evita 4 PCV

67. DRÄGER Evita XL SIMV

68. Adjunct Ventilator Settings and curves

69. 1. Oxygen
The fraction of inspired O2 (FiO2) is set in a range from 21% (room air; not generally indicated) to 100%
In the ED it is common to start at 100% FiO2 to ensure adequate oxygenation and titrate the FiO2 down to nontoxic levels (FiO2< 60%) following the SaO2 via the pulse oximeter (SaO2> 90%) during first 72 h.
some practitioners recommend using 95% O2 as the upper limit of FiO2

70. 2. Inspiration : Expiration (I:E) Ratio
The normal I:E ratio in a spontaneously breathing, non intubated patient is 1:4
Intubated patients commonly achieve I:E ratios of 1:2

71. 3. Flow rate (Q ) This is the rate of gas delivery (L/min).
The range of flows that can be achieved by current ventilation is from 10 to 160 L/min.
Common flow settings are from 40 to 75 L/min.
The higher the flow rate, the faster the ventilator will reach its set volume or pressure.
Start at Q=60 L/ min
A faster flow rate  decreased ins. time
A slower flow rate  decreased exp. time

72. Flow-time diagram
VCV
PCV

74. Initial ventilator setting

75. Pressure triggering
The sensitivity of the trigger can be adjusted by changing the pressure drop required for inspiratory cycling to be triggered, and this can be set to a value between −1 cm H2O (very sensitive) and −20 cm H2O (very insensitive)
If the setting is too sensitive, minor fluctuations in breathing circuit pressure (e.g. from cardiac pulsations) can trigger the ventilator inappropriately.

76. Flow triggering
The reduction in return flow that has to be detected for triggering to occur can be adjusted between 1 (very sensitive) and 10 (insensitive) L/min
Flow triggering is considered to require less work from the patient to initiate a breath and therefore may enhance patient comfort and reduce the work of breathing.

77. Advanced modes BREATH TO BREATH WITHIN A BREATH
Pressure-regulated volume control (PRVC)
Auto flow
Volume control plus (VC+)
Adaptive pressure ventilation (APV)
Variable-pressure control (VPC)
WITHIN A BREATH
Volume-assured pressure support ventilation (VAPSV)
Pressure augmentation

78. Other modes High Frequency Ventilation Proportional assist ventilation
Airway Pressure Release Ventilation (Bi-level ventilation)  PCV
T high : 4 – 6 s T low : 0.2 – 1.5 s
P high : up to 40 cmH2O P low : 10 cmH2O

79. NON INVASIVE VENTILATION
TUMS

80. TUMS

81. Noninvasive Ventilation
For prevention of invasive MV in selected patients
No need to definitive airway control
Candidates :
COPD, CHF, Asthma, hypoxia, DNR patients and Immunocompromised patients
1. the airway must be patent,
2. the respiratory drive must be intact,
3. the patient must be cooperative (i.e., awake and alert).
TUMS

83. Serial assessment and close monitoring Q 30 min ABG Q 1-2 h
Contraindications:
Near arrest
Severe GIB
Anatomic defect of face
Up airway obstruction
AMS
Risk of aspiration and defect in secretion clearance

84. Nasal mask
TUMS

85. Advantages of NIV The potential benefits of NIV over MV are:
a decrease in potential airway injury
decrease in VAP
probably a shorter length of stay
Eating and speech reserved
TUMS

86. Disadvantages of NIV Pulmonary baro-trauma (volu-trauma)
pressure necrosis of the facial skin, subcutaneous tissue and musculature and patient discomfort
aerophgia  gastric dilation  vomiting and aspiration
hemodynamic compromise
TUMS

87. TUMS

88. Bi-level ventilation Bi-level ventilation.
A: Baseline pressure cycles between Plow and Phigh with spontaneous, unsupported, patient breaths during high and low phases.
Transition from low to high phase is synchronized to the patient’s inspiration, and transition from high to low phase is synchronized to patient’s expiration.
B: As in A, but now inspiratory efforts during the Plow phase trigger support (Psupp).

89. Bi-level ventilation Bi-level ventilation.
C: As in A, but now inspiratory effort during both Plow and Phigh phase trigger support which is targeted to the same absolute support pressure (Psupp).
If Phigh is greater than Psupp, patient effort during Phigh becomes unsupported.
D: As in A, but now inspiratory effort during both Plow and Phigh phase trigger support which is set specifically for each phase,relative to the baseline pressure of the phase.

90. Approach to NIPPV In hypoxemia: EPAP + 2 cmH₂O and fix interval IPAP
In hypercapnia:
IPAP cmH₂O and EPAP= 40% IPAP
TUMS

91. High flow nasal cannula
… can deliver warm and humidified air up to 40 L/min

92. 5 Special Circumstances and applying ventilatory support
TUMS

93. 1. Severe Acute Lung Injury and ARDS
Preferred PCV
consider permissive hypercapnia.
If able to achieve P02> 60 mm Hg on FiO2<60%, the PCO2 may be allowed to be >40 mm Hg if pH> 7.25.
if needed, use NaHCO3
Tv  6 – 8 ml / kg
F  20 – 25 / min
PEEP  8
Monitor P plateau: if > 30 cm H2O  Tv : 4 ml/kg
TUMS

94. 2. Severe Asthma and COPD The defect is decreased gas flow.
In conventional ventilation use higher flow rate and lower respiratory rate to allow more time for exhalation.
Tv  ml / kg
F  8 – 10 / min
Q 80 l/min
PEEP  5 ( % intrinsic PEEP)
Detection of intrinsic PEEP with wean and chest compression
Optimal P plateau < 30 cmH2O
TUMS

95. Monitoring of treatment in asthma

96. 3. Pulmonary edema NIPPV is preferred
If the patient is intubated  PEEP is useful
But in hypotensive patients  min. PEEP with continuous evaluation
TUMS

97. 5. Traumatic brain injury
Do not lower PC02 < 35 mm Hg, as it may induce severe cerebral vasoconstriction and lead to cerebral ischemia.
The goal is PC02: mm Hg.
Acceptable to hyperventilate for a patient with an acute herniation syndrome as a bridging maneuver for definitive therapy.
TUMS

98. Overdose in healthy patient
General Guidelines for Initial Invasive Ventilator Settings in Various Clinical Settings / Rosen`s EM
Mode
FIO2 (%)
VT (mL/kg)
F / min
I/E
PEEP (cm H2O)
Overdose in healthy patient
CMV, A/C, IMV, SIMV 95
8–10
10–12
1:2
0–5
Status asthmaticus
5–10
8–12
1:4
2.5–10
COPD exacerbation
1:3–1:4
pulmonary edema
8-10
2.5–15
ARDS
6-8
20-25
2.5-10
Hypovolemic shock -
0-5

99. complications Pneumothorax Ventilator induced lung injury
Hemodynamic instability
Difficult trigger ventilation
Auto-cycling (seizure, shivering)
Outstripping and double cycling (demand over Vt)
Straining over the ventilator (demand over Q)
Coughing
Failure to MV

100. Approach to res. distress

101. Weaning

102. Indications for extubation
No weaning parameter completely accurate when used alone
Numerical Parameters
Normal
Range
Weaning Threshold
P/F
> 400
> 200
Tidal volume
5 - 7 ml/kg
5 ml/kg
Respiratory rate
breaths/min
< 40 breaths/min
Vital capacity
ml/kg
10 ml/kg
Minute volume
5 - 7 L/min
< 10 L/min
Greater Predictive Value
NIF (Negative Inspiratory Force)
> - 90 cm H2O
> - 25 cm H2O
RSBI (Rapid Shallow Breathing Index) (RR/TV)
< 50
< 100
Clinical parameters
Resolution/Stabilization of disease process
Hemodynamically stable
Intact cough/gag reflex
Spontaneous respirations
Acceptable vent settings
FiO2< 40%, PEEP < 8, PaO2 > 75, pH > 7.25
Disorders characterized by systemic effects of M protein, and direct effects of bone marrow infiltration
Common examples of methylation-induced silencing:
Imprinted genes (Prader-Willi, Angelmann Syndromes)
Inactivated 2nd X chromosome in females
DNA methylation results in histone deacetylation, compacted chromatin, and repression of gene activity
Methylation can have a profound effect in tumorigenesis by silencing tumor suppressors
Marino P, The ICU Book (2/e)

103. The cause of respiratory failure is improving or has been eliminated,
Criteria :
The cause of respiratory failure is improving or has been eliminated,
FiO2 < 0.40
PEEP < 8cm H2O
No pressors other than
dopamine at <5 μg/kg / min or Epinephrine or NorEpi. at < 0.05 µg /kg / min.
TUMS

104. weaning

105. <105 /L Parameter Normal Adult range Threshold for weaning
PaO2/FiO2
>400
200
Tidal Volume
5-7 ml/kg
5 ml/kg RR
14-18 /min
<40 /min
Minute Vent.
5-7 L/min
<10 L/min
Vital capacity
65-75 ml/kg
10 ml/kg
Peak Inspiratory Pressure
>90 cmH2O (F)
>120 cmH2O (M)
25 cmH2O
RSBI (f/Vt)
<50 /L
<105 /L
TUMS

106. The Problem Wean RAPID BREATHING  1 1. Check Vt
Low Vt  Resume vent. support
Vt not low  2
2. Check PaCO2
PaCO2 decreased  sedate (anxiety)
PaCO2 not decreased  Resume vent.
TUMS

107. HYPOXEMIA : May be due to low C.O. HYPERCAPNEA:
ABDOMINAL PARADOX :
Inward displacement of the diaphragm during inspiration is a sign of diaphragmatic muscle fatigue
HYPOXEMIA : May be due to low C.O.
HYPERCAPNEA:
Increase in PaCO2-PetCO2
= increase dead space ventilation
Unchanged gradient: Respiratory muscle fatigue or enhanced CO2 production
TUMS

108. Weaning

109. Tracheal Decannulation
Successful weaning is not synonymous with tracheal decannulation
If weaned and not fully awake or unable to clear secretions, leave ETT in place
Tracheal decannulation increases the work of breathing due to laryngeal edema and secretions
Do not perform tracheal decannulation to reduce work of breathing
TUMS

110. Inspiratory Stridor
Post extubation inspiratory stridor is a sign of severe obstruction and should prompt re-intubation
Laryngeal edema (post-ext) may respond to aerosolized epinephrine in children
Steroids have no role
Most need reintubation followed by tracheostomy
TUMS

111. TUMS

112. Case management
TUMS

113. Case 1
An l8-year-old otherwise healthy 60-kg female presents with an overdose of benzodiazepines.
She requires intubation for airway protection and ventilatory support.
There is no evidence of aspiration or an intrinsic lung problem.
TUMS

114. With VCV setting Target Vm = 7.2 L / min
It is reasonable to assume a normal need for Vm since she has no evidence of hypoperfusion or infection, and she has not ingested an medications known to cause a metabolic acidosis that would require a higher Vm to buffer by induced hypocarbia.
TUMS

115. Dräger evAita 2
Patient data
Ventilator setting
Alarm setting
TUMS

116. Vt and f F= 12 /min Vt = 600 mL (7-10 mL/kg)
This setting will guarantee the desired Vm even if the patient continues to develop respiratory depression from the benzodiazepine ingestion.
TUMS

117. Pressure Support Ventilation.
Initiate PSV at 10 cm H20 pressure, and then titrate up or down to achieve a spontaneous breath Vt approximately equal to that of the set Vt.
TUMS

118. Gas Delivery Waveform: Begin with a decelerating waveform.
Maximal Inspiratory Flow :
Set the initial Q at 60 L/min.
lower Q(Q = 50 L/min) in hypoxemia
higher flow (Q = 70 L/min) in exhalation obstruction (e.g. COPD), then evaluate the resultant Paw-peak.
TUMS

119. If the Q is reduced to 40 L/min and the Paw-peak remains high, :
If the Vt is appropriate, reduce the flow rate by L/min and re-evaluate; repeat if necessary.
If the Q is reduced to 40 L/min and the Paw-peak remains high, :
1) the Vt is, in fact, too large for the available lung mass,
2) there is a tube obstruction (partial)
3) the patient has a pleural space occupying disorder (pneumo-, hemo-, hemopneumo-, or hydro-thorax),
4) the patient requires a different mode
5) there is a ventilator dysfunction
TUMS

120. Order writing 2 1 Then titrate PSV to achieve Vt spont. 600 ml SIMV
ABG 20 min later 1
SIMV
f : 12/ min
FiO2 : 95%
PEEP : 5 cm H2O
ASB / CPAP / PSV : 10 cm H2O
Flow : 60 L/min Ramp wave
TUMS

121. The same patient with PCV setting
Vm = 7.2 L/min
Mode = ( in E4 , 2 ) PCV+ SIMV, .PCV. PSV. ASB
Q = 160 L/min
( devise adjust the Q in response to the patient`s breath.)
Wave = ramp
F = 12/ min
FiO2= 95%
PSV =10 cm H2O
PEEP=5 cm H2O
(Paw Peak )
=PC+ PEEP
=25 PC
=[(Paw peak) – PEEP] ×2/3
= (35 – 5)× 2/3
=20 cm H2O
TUMS

122. Order writing 2 1 PC : 20 cm H2O PEEP :5 cm H2O PSV : 10 cm H2O
Q : max (160) L/min
Wave : ramp
ABG 20 min later 1
SIMV
f : 12/ min
PC : 20 cm H2O
Ti : 1 s
FiO2 : 95 %

123. Case 2
A 45-year-old, 70-kg male presents with high fevers, cough, and shortness of breath.
The ED portable chest film demonstrates bilateral infiltrates as well as lower lobe air bronchograms.
While awaiting admission to the hospital for presumed community-acquired pneumonia, the patient develops hypoxia, suffers respiratory failure, and requires urgent intubation.
TUMS

124. Mode : SIMV-As before, allow the patient to breathe spontaneously when the short acting neuromuscular blockers or heavy sedative (e.g., etomidate, fentanyl, midazolam) used to facilitate intubation wears off.
Target Vm :Given the likely acidosis, this patient's Vm needs to exceed the lower limit of normal value.
Thus, a target of 9.8 L/minute is a 40% increase above the baseline .
TUMS

125. initial f= 14 / min
Vt = 700 ml
One must evaluate the resultant Paw-peak after starting at this setting.
One may also need to reduce the tidal volume and increase the rate if the Paw-peak is high and no other mode of ventilation is available.
TUMS

126. Fi02 : Begin with FiO2 :95% then titrate.
PEEP : ≥5 (to maintain FRC and alveolar recruitment with V/S consideration )
Flow:
A longer Ti is ideal for alveolar recruitment and a slow flow rate will complement the decelerating waveform and further prolong the Ti.
Then start with a Q of 50 L/min
TUMS

127. In PCV : the same MODE & Vm … Only set the Ti & PC (longer Ti)
Start with a higher PSV because the pulmonary compliance is less than the normal lungs.
Initiate PSV at 15 cm H20 and titrate to achieve similar Vt with the machine and spontaneous breaths.
In PCV : the same MODE & Vm …
Only set the Ti & PC (longer Ti)
Then reevaluate the patient`s condition
TUMS

128. The end
TUMS