1. Mechanical ventilationMechanical ventilation
 Mech. Ventilation is an invasive lifeMech. Ventilation is an invasive life
support procedure .support procedure .
 The goal is to optimize both gasThe goal is to optimize both gas
exchange and clinical status at aexchange and clinical status at a
minimum FiO2 & ventilatorminimum FiO2 & ventilator
pressures .pressures .

2. Indications for respiratory support:Indications for respiratory support:
(1) Relative indications(1) Relative indications::
 frequent intermittent apnea unresponsive to drugfrequent intermittent apnea unresponsive to drug
therapy.therapy.
 Early treatment when use of mech. Vent. IsEarly treatment when use of mech. Vent. Is
anticipated bec. Of deterioration of bl.gases.anticipated bec. Of deterioration of bl.gases.
 Relieving "work of breathing" in an infant withRelieving "work of breathing" in an infant with
signs of resp. difficulty.signs of resp. difficulty.
 Initiation of exogenous surfactant therapy inInitiation of exogenous surfactant therapy in
infants with RDS.infants with RDS.

3. (2)(2) Absolute indicationsAbsolute indications::
 prolonged apneaprolonged apnea
 PaO2 < 50 mm Hg on FiO2PaO2 < 50 mm Hg on FiO2 0.800.80
 PaCO2 > 60 mm Hg with persistent acidemia (art.PH 7.).PaCO2 > 60 mm Hg with persistent acidemia (art.PH 7.).
 CNS insult with affection of resp.CNS insult with affection of resp.
 General anaesthesiaGeneral anaesthesia

4. **Continuous positive air way pressur (CPAPContinuous positive air way pressur (CPAP(.(.
 Acont. Flow of heated, humidified gas inAcont. Flow of heated, humidified gas in
circulated post the infant's airway at a set pressurecirculated post the infant's airway at a set pressure
of 3-8 cm H2Oof 3-8 cm H2O
 Maintaining an elevated end – expiratory lungMaintaining an elevated end – expiratory lung
volume while the infant breaths spontaneously.volume while the infant breaths spontaneously.
 The air oxygen mix. and airway pressure can beThe air oxygen mix. and airway pressure can be
adjusted.adjusted.
 CPAP is usually delivered by means of nasalCPAP is usually delivered by means of nasal
pronges or nasopharyngeal tube.pronges or nasopharyngeal tube.
N.B: prolonged ET CPAP is not used bec. The highN.B: prolonged ET CPAP is not used bec. The high
resistence of the ET tube increases the work ofresistence of the ET tube increases the work of
breathing esp. in small infants.breathing esp. in small infants.

5. Advantages of CPAP:Advantages of CPAP:
 Less invasive, less barotrauma.Less invasive, less barotrauma.
 When used in infants with RDS, it canWhen used in infants with RDS, it can
help and prevent alveolar and airwayhelp and prevent alveolar and airway
collapse, which might result incollapse, which might result in
deterioration of PO2.deterioration of PO2.
 CPAP decreased frequency ofCPAP decreased frequency of
obstructive & mixed apnaeic spells inobstructive & mixed apnaeic spells in
some infants.some infants.

6. Disadvantages:Disadvantages:
 does not improve ventilation & may worsen it.does not improve ventilation & may worsen it.
 In adequate resp. support in cases ofIn adequate resp. support in cases of
severe RDS.severe RDS.
 Maintaining nasal or nasophary. CPAP inMaintaining nasal or nasophary. CPAP in
large active infants may technically belarge active infants may technically be
difficult .difficult .
 Swallowed air can elevate the diaphragm &Swallowed air can elevate the diaphragm &
must be removed by a gastric tube.must be removed by a gastric tube.

7. Indications of CPAP:-Indications of CPAP:-
 Early treatment of mild RDS.Early treatment of mild RDS.
 Moderately frequently apnaeic spells.Moderately frequently apnaeic spells.
 Weaning chronically ventilator-Weaning chronically ventilator-
dependent infantsdependent infants..

8. I.M.V:I.M.V:
Pressure limited, time cycled, cont. flow ventilator:Pressure limited, time cycled, cont. flow ventilator:
 cont. flow of heated & humidified gas iscont. flow of heated & humidified gas is
circulated past the infant's air way.circulated past the infant's air way.
 The gas is a selected mixture of air withThe gas is a selected mixture of air with
oxygen.oxygen.
 Max. insp. Pressure (PIP) and positive endMax. insp. Pressure (PIP) and positive end
exp. Pr. (PEEP) are selected.exp. Pr. (PEEP) are selected.
 Resp. timing (rate & duration of insp. &Resp. timing (rate & duration of insp. &
exp.) is selected:exp.) is selected:

9. Advantages:Advantages:
1.1. the continuous flow of fresh gas allows thethe continuous flow of fresh gas allows the
infants to make spont. resp. effortsinfants to make spont. resp. efforts
between vent. breaths. (intermittentbetween vent. breaths. (intermittent
mandatory ventilation (IMV).mandatory ventilation (IMV).
2.2. Good control is maintained over resp.Good control is maintained over resp.
pressures.pressures.
3.3. Insp. and exp. Time can be controlled.Insp. and exp. Time can be controlled.
4.4. System is relatively simple & in expensive.System is relatively simple & in expensive.

10. Disadvantages:Disadvantages:
1.1. Tidal vol. is poorly controlled.Tidal vol. is poorly controlled.
2.2. The system does not respond to changes inThe system does not respond to changes in
resp.system compliance.resp.system compliance.
3.3. The patient can take breaths on his or her ownThe patient can take breaths on his or her own
but the vent. May cycle on during a patientbut the vent. May cycle on during a patient
breathbreath  asynchrony.asynchrony.
4.4. Spont. breathing infants who breath out of phaseSpont. breathing infants who breath out of phase
with to many IMV breaths (Bucking' or fightingwith to many IMV breaths (Bucking' or fighting
the ventil). May receive inadequate vent. & are atthe ventil). May receive inadequate vent. & are at
increased risk for air leak.increased risk for air leak.
Indications: Useful in any form of lungIndications: Useful in any form of lung
disease in infants.disease in infants.

11. SIMVSIMV
Synchronized IMVSynchronized IMV
 Adaptation of conventional pressure limitedAdaptation of conventional pressure limited
ventilator.ventilator.
 These vent. Combine the features ofThese vent. Combine the features of
pressure limited, time cycled. Contin. Flowpressure limited, time cycled. Contin. Flow
ventilators withventilators with
 air way pressureair way pressure
 air flowair flow SensorSensor
OrOr  resp. movementresp. movement

12.  By measuring insp. Flow or movement,By measuring insp. Flow or movement,
these ventilators deliver intermittentthese ventilators deliver intermittent
positive pressure breaths at a fixed ratepositive pressure breaths at a fixed rate
in synchrony with the baby'sin synchrony with the baby's
inspiratory effort and allows the patientinspiratory effort and allows the patient
to finish expirat. Before cycling onto finish expirat. Before cycling on
(synchronized IMV, or SIMV) :(synchronized IMV, or SIMV) :
 During apnea, SIMV ventilatorsDuring apnea, SIMV ventilators
continue to deliver the set of IMV rate.continue to deliver the set of IMV rate.

13. Pressure support ventilator (patientPressure support ventilator (patient
triggered ventilation).triggered ventilation).
 Insp. Effort opens a valve allowing air flow atInsp. Effort opens a valve allowing air flow at
preset +ve pi.preset +ve pi.
 In patient triggered vent., a +ve pi breath isIn patient triggered vent., a +ve pi breath is
delivered with every insp. Effort.delivered with every insp. Effort.
 Patient determines rate & insp. Time.Patient determines rate & insp. Time.
 As a result, the ventilator delivers more frequentAs a result, the ventilator delivers more frequent
+ve Pi breaths, usually allows decrease in PIP+ve Pi breaths, usually allows decrease in PIP
needed for adeq. Gas exchange.needed for adeq. Gas exchange.
 During apnea, the vent. In patient triggered modeDuring apnea, the vent. In patient triggered mode
delivers an operator – selected IMV (control) ratedelivers an operator – selected IMV (control) rate
(Assisst – control)(Assisst – control)

14. Advantages of SIMV & PSV :Advantages of SIMV & PSV :
 synchronizing the delivery of +ve pr breaths withsynchronizing the delivery of +ve pr breaths with
the infant insp. effort reduces the phenomena ofthe infant insp. effort reduces the phenomena of
breathing out of phase with IMV breathsbreathing out of phase with IMV breaths
(Fighting the ventilator), this may decreased the(Fighting the ventilator), this may decreased the
need for sedative medications & aid in weaningneed for sedative medications & aid in weaning
mechanically ventilated infants.mechanically ventilated infants.
 Pronounced asynchrony with ventilator breathsPronounced asynchrony with ventilator breaths
during conventional IMV has been associatedduring conventional IMV has been associated
with the development of air leak & IV he.with the development of air leak & IV he.

15. Disadvantages:Disadvantages:
The ventilator may inappropriatelyThe ventilator may inappropriately
trigger a breath bec. Of artifacturaltrigger a breath bec. Of artifactural
signal or fail to trigger bec. Ofsignal or fail to trigger bec. Of
problems with the sensorproblems with the sensor ..

16. Indications:Indications:
SIMV & PSV. Can be used when aSIMV & PSV. Can be used when a
conventional pressure limited ventilatorconventional pressure limited ventilator
is indicated.is indicated.
If available, it may be the preferableIf available, it may be the preferable
mode of ventilator therapy in infantsmode of ventilator therapy in infants
who are breathing spontaneously onwho are breathing spontaneously on
IMV.IMV.

17. Ventilator parameters:Ventilator parameters:
(1) Peak insp. Pressure (PIP):(1) Peak insp. Pressure (PIP):
 Max. insp. Pressure attained during theMax. insp. Pressure attained during the
resp. .resp. .
 Main determinant of tidal volume whenMain determinant of tidal volume when
using pressure control V.using pressure control V.
 Set at minimum pressure required toSet at minimum pressure required to
achieve chest movement with adequate airachieve chest movement with adequate air
entry on auscultation, in order to reduceentry on auscultation, in order to reduce
complication from barotrouma.complication from barotrouma.

18. (2) Positive end. Exp. Pressure (PEEP):(2) Positive end. Exp. Pressure (PEEP):
 air way pressure maintained bet. Insp. & exp.air way pressure maintained bet. Insp. & exp.
Phases.Phases.
- Prevent alveolar collapse during expiration.- Prevent alveolar collapse during expiration.
- Decreased work of reinflation.- Decreased work of reinflation.
 Improve gas exchange.Improve gas exchange.
 Minimum physiological PEEP is2 cmH2OMinimum physiological PEEP is2 cmH2O
 Start at level of 4-7 cm H2OStart at level of 4-7 cm H2O
 PCO2 may rise with increasing PEEP.PCO2 may rise with increasing PEEP.

19. (3) Rate : Number of mech. Breaths delivered per(3) Rate : Number of mech. Breaths delivered per
minute (in IMV.) or freq: rate of oscillation inminute (in IMV.) or freq: rate of oscillation in
HFOV :HFOV :
 Major effect on minute volume and thus PCO2Major effect on minute volume and thus PCO2
 Initial settings may vary from 20-100 depending orInitial settings may vary from 20-100 depending or
gestational age & underlying diseased.gestational age & underlying diseased.
(4) Inspired oxygen concentration (FiO2):(4) Inspired oxygen concentration (FiO2):
 Fraction of O2 present in inspired gas.Fraction of O2 present in inspired gas.
 Select FiO2 0.05 higher than before ventilation.Select FiO2 0.05 higher than before ventilation.
 High FiO2 > 60-70 carries risk of lung toxicity.High FiO2 > 60-70 carries risk of lung toxicity.
 FiO > 80% leads to resorption collapse which mayFiO > 80% leads to resorption collapse which may
worsen the condition.worsen the condition.

20. (5) Inspiratory time (Ti):(5) Inspiratory time (Ti):
 Length of time spent in the insp. phase ofLength of time spent in the insp. phase of
resp. cycle.resp. cycle.
(6) I:E ratio:(6) I:E ratio:
 Ratio of insp. to exp. Time.Ratio of insp. to exp. Time.
 Normal ratio 1:1 to 1:3 are used.Normal ratio 1:1 to 1:3 are used.
 Reversed ratio with prolonged insp. Time e.gReversed ratio with prolonged insp. Time e.g
3:1 result in improved oxygenation, but rarely3:1 result in improved oxygenation, but rarely
used bec. Of risk of air leak as result of airused bec. Of risk of air leak as result of air
trapping.trapping.

21. (7) Flow rate :(7) Flow rate :
 normal setting of 6-12 L/min.normal setting of 6-12 L/min.
 start at 5-7L/min & increased to achievestart at 5-7L/min & increased to achieve
higher pressure settings – always usehigher pressure settings – always use
minimum flow rate to achieve PIP as highminimum flow rate to achieve PIP as high
flow increased air way resistance & mayflow increased air way resistance & may
overdistend with lung.overdistend with lung.

22. (8) Mean air way pressure (MAP):(8) Mean air way pressure (MAP):
 average pressure over entire resp. cycle.average pressure over entire resp. cycle.
MAP =MAP = (PIP X Ti) + (PEEP X Te )(PIP X Ti) + (PEEP X Te )
(Ti + TE)(Ti + TE)
 changes in flow, PEEP, PIP, Ti, VR willchanges in flow, PEEP, PIP, Ti, VR will
alter MAP.alter MAP.
 Correlates directly with oxygenation.Correlates directly with oxygenation.
 High MAP is associated with increasedHigh MAP is associated with increased
risk of barotraumas & air leak.risk of barotraumas & air leak.

23. N.B:N.B:
 Main ventilator determinats for PaO2 are FiO2 &Main ventilator determinats for PaO2 are FiO2 &
MAPMAP
 - Main ventilator determinats for PCO2 are PIP &- Main ventilator determinats for PCO2 are PIP &
VR.VR.
Initial suggested settings:Initial suggested settings:
 setting should be altered to obtain synchrony of thesetting should be altered to obtain synchrony of the
infants resp. effort with ventilator by : decreaseinfants resp. effort with ventilator by : decrease
Ti , increased rate.Ti , increased rate.
 If this fails, ms relaxation may be used (rarely usedIf this fails, ms relaxation may be used (rarely used
for babies < 1000 gm).for babies < 1000 gm).

24. Table 9.3. Suggested initial ventilator settingsTable 9.3. Suggested initial ventilator settings
Infant with
normal
lungs
RDS infant
< 2000 g
RDS infant
> 2000 g
FIO2
As indicated by
oximetry
As indicated by
oximetry
As indicated by
oximetry
PIP (cdmH2
O) 14-18 18-25 20-30
PEEP (cmH2O) 2-3 3-5 3-6
Rate (bpm) 15-25 60-100 40-60
Inspiratory time
(Ti
) (S)
0.4=0.5 0.3-0.5 0.4-0.6

25. Monitoring during mechanical ventilation:Monitoring during mechanical ventilation:
 ABC should be checked within 20 min of startingABC should be checked within 20 min of starting
mech. Ventilation.mech. Ventilation.
 Ventilator settings adjusted to obtain satisfactoryVentilator settings adjusted to obtain satisfactory
bl. Gasesbl. Gases
Aim:Aim: Pa CO2Pa CO2 35-45 mmHg35-45 mmHg
Pa O2Pa O2 53-75 mmHg53-75 mmHg
PH > 7.25PH > 7.25
 Repeat bl. Gases with in 30 min. of alterations ofRepeat bl. Gases with in 30 min. of alterations of
ventilator setting.ventilator setting.
 Where ventilation is stable, check bl. Gases at aWhere ventilation is stable, check bl. Gases at a
minimum of 4 hr interval.minimum of 4 hr interval.
 Oxygenation should be monitored continuouslyOxygenation should be monitored continuously
with pulse oxy..with pulse oxy..

26. How ventilator changes affect blood gasesHow ventilator changes affect blood gases
(A) Oxygenation:(A) Oxygenation:
(1) FIO2 : increasing the FiO2 is the(1) FIO2 : increasing the FiO2 is the
simplest & most direct means ofsimplest & most direct means of
improving oxygenation.improving oxygenation.
 In preterm infants, the risk of retinopathy &In preterm infants, the risk of retinopathy &
pulmonary toxicity are present.pulmonary toxicity are present.

27. (2) MAP : increased by :(2) MAP : increased by :
 PEEP , PIP, Ti, R, flow RPEEP , PIP, Ti, R, flow R
 All these changes lead to higher PO2, but each hasAll these changes lead to higher PO2, but each has
different effect on PCO2..different effect on PCO2..
 Optimum MAP results from a balance betweenOptimum MAP results from a balance between
optimizing PO2, minimizing direct O2 toxicity,optimizing PO2, minimizing direct O2 toxicity,
minimizing barotraumas adeq. Ventil.minimizing barotraumas adeq. Ventil.
 MAP as low as (5) may be sufficient in infants withMAP as low as (5) may be sufficient in infants with
normal lung.normal lung.
 Where as (20) cm H2O may be necessary in severeWhere as (20) cm H2O may be necessary in severe
RDS.RDS.
 Excessive MAP may impede V.R. & adversely affectExcessive MAP may impede V.R. & adversely affect
C.O.P.C.O.P.

28. (B) Ventilation(B) Ventilation
 CO2 elimination depends on minute ventilation.CO2 elimination depends on minute ventilation.
 Since M. vent. Is the product of R.R. & T.V., increased inSince M. vent. Is the product of R.R. & T.V., increased in
ventilatory rate will lower PCO2.ventilatory rate will lower PCO2.
 Increased tidal vol. can be achieved by increased PIP.Increased tidal vol. can be achieved by increased PIP.
 Decreased PEEP will also improve ventilation.Decreased PEEP will also improve ventilation.
 Optimal PCO2 varies according to disease state.Optimal PCO2 varies according to disease state.
* For very immature infants or infants with air leak PCO2* For very immature infants or infants with air leak PCO2
50-60 may be tolerated to minimize barotrauma provided50-60 may be tolerated to minimize barotrauma provided
PH > 7.25.PH > 7.25.
* When hyperventilation is used to reduce pulmonary* When hyperventilation is used to reduce pulmonary
resist. PCO2 as low as 30 mmHg may beresist. PCO2 as low as 30 mmHg may be required.required.

29. Complications of Mech. VentilationComplications of Mech. Ventilation
AC complicationsAC complications:-:-
1-1- Tube problems:-Tube problems:-
trauma to nose, palate, larynx trachea.trauma to nose, palate, larynx trachea.
Infection.Infection.
Displacement, blockage, kinking.Displacement, blockage, kinking.
2-2- Circuit tubing problems: gas leak, water obst. OrCircuit tubing problems: gas leak, water obst. Or
inhalation, kinking.inhalation, kinking.
3-3- Humidi fier: gas leakes, overheating, infection,Humidi fier: gas leakes, overheating, infection,
esp. pseudomon.esp. pseudomon.
4-4- Gas supply: Failure, air / oxygen mix.Gas supply: Failure, air / oxygen mix.
5-5- Ventilator failure: raised pressureVentilator failure: raised pressure  pneumoth.pneumoth.
Interstial emphysema.Interstial emphysema.

30. CH. Complication:-CH. Complication:-
Airway:Airway:
* Trauma with deformities of nose.* Trauma with deformities of nose.
* Subglottic stenosis.* Subglottic stenosis.
* Tracheal ulceration.* Tracheal ulceration.
* Palatal groove.* Palatal groove.
LungsLungs : - broncho pulm. Dysplasia.: - broncho pulm. Dysplasia.
- post extubation collapsed.- post extubation collapsed.

31. Main causes of sudden deterioration Mech.Main causes of sudden deterioration Mech.
Ventilator:Ventilator:
 Mech. Failure.Mech. Failure.
 Tube blockage or displacement.Tube blockage or displacement.
 Preumothorax.Preumothorax.
 Perivent ricular hge.Perivent ricular hge.
Check ventilator is working, disconnect, andCheck ventilator is working, disconnect, and
manually ventilate infant.manually ventilate infant.
 If improvement occurs mech failure is likely.If improvement occurs mech failure is likely.
 If no improvement assess potency of tube &If no improvement assess potency of tube &
exclude pneumo thorax.exclude pneumo thorax.

32. Causes of gradual eleterioration:Causes of gradual eleterioration:
InfectionInfection
- PDA- PDA
- slowly progressive interstitial emphysema.- slowly progressive interstitial emphysema.
Weaning from ventilation:Weaning from ventilation:
 This is as important as ventilation therapy itself since theThis is as important as ventilation therapy itself since the
condition of the baby may be worsen by poor weaning.condition of the baby may be worsen by poor weaning.
 It is made easier by use of intermittent mandatoryIt is made easier by use of intermittent mandatory
ventilator (IMV).ventilator (IMV).
 This allows ventilatory R. to be reduced & the infant toThis allows ventilatory R. to be reduced & the infant to
breath between each mech. Vent.breath between each mech. Vent.
 SIMU more valuable in weaning from ventilator >SIMU more valuable in weaning from ventilator >
Indication::- Bl. Gases :Indication::- Bl. Gases : PCO2 < 50PCO2 < 50
PH > 7.3PH > 7.3
PO2 > 53PO2 > 53
Ventilator:Ventilator: FiO < 0.5FiO < 0.5
PIP < 25 cmH2OPIP < 25 cmH2O

33. Technique:Technique:
1.1. before weaning ensure ms. Relaxantbefore weaning ensure ms. Relaxant
have been discontinued, sedationhave been discontinued, sedation
reduced & max. coloric in takereduced & max. coloric in take
obtained.obtained.
2.2. When start weaning, make smallWhen start weaning, make small
changes. Readucing PIP 1st by 1-2changes. Readucing PIP 1st by 1-2
cmH2OcmH2O
3.3. Reduce insp. O2 content by 5% atReduce insp. O2 content by 5% at
time & VR by 5 breath / min at atime & VR by 5 breath / min at a

34. N.B:N.B:
When lowering V.R, remember to adjust IEWhen lowering V.R, remember to adjust IE
ratio so that, Ti remains to about 0.4 – 0.5 Sec.ratio so that, Ti remains to about 0.4 – 0.5 Sec.
1-1- Check bl. Gases with in 60 min of each change toCheck bl. Gases with in 60 min of each change to
ensure that pa CO2 is not rising.ensure that pa CO2 is not rising.
3-3- Endotracheal CPAP can be employed when :Endotracheal CPAP can be employed when :
PIP < 15 , FIO2 < 40, VR < 10PIP < 15 , FIO2 < 40, VR < 10
3-3- Give resp. stimulants such as aminophylline orGive resp. stimulants such as aminophylline or
caffeine during weaning to improve chance ofcaffeine during weaning to improve chance of
successful extubationsuccessful extubation

35. Extubation:Extubation:
 usually attempted only after a successfulusually attempted only after a successful
period of hrs. on endotracheal CBAB.period of hrs. on endotracheal CBAB.
 An exception to this rule is the veryAn exception to this rule is the very
immature infant who has been ventilatedimmature infant who has been ventilated
through 2.5 cm tube, since breathing isthrough 2.5 cm tube, since breathing is
difficult due to high resistance in this narrowdifficult due to high resistance in this narrow
tube.tube.
 A very immature infants may be successfullyA very immature infants may be successfully
extubated when they have tolerate IMV of 10extubated when they have tolerate IMV of 10
breaths/min.breaths/min.

36. Technique:Technique:
1.1. Avoid feeding infant before extubation or emptyAvoid feeding infant before extubation or empty
stomach to prevent vomiting.stomach to prevent vomiting.
2.2. Suction nasoph. Well.Suction nasoph. Well.
3.3. Remove tube on inflation to achieve adeq.Remove tube on inflation to achieve adeq.
Inflation & prevent post extubation collapse.Inflation & prevent post extubation collapse.
4.4. Place infant on well humidified O2 hood withPlace infant on well humidified O2 hood with
FiO2 concent. The same as before extubation.FiO2 concent. The same as before extubation.
If this infant less than 1500 gm place on nasalIf this infant less than 1500 gm place on nasal
pronge CPAP to decreased incidence of collapse.pronge CPAP to decreased incidence of collapse.
5-5- ABG 30 min after extubation.ABG 30 min after extubation.
6-6- X-ray chest 4 hr later to look for collapse if FiO2 .X-ray chest 4 hr later to look for collapse if FiO2 .
7-7- Physiotherapy & gentle suctioning of u. air wayPhysiotherapy & gentle suctioning of u. air way
are helpful.are helpful.

37. Table 6-3. CAUSES OF WEANING FAILURETable 6-3. CAUSES OF WEANING FAILURE
Slow resolution of
underlying disease.
Inspiratory muscle
loading
Persistent atelectasis Asynchrony with ventilator
Pulmonary edema Muscle injury or disease
Lower airway obstruction Pphrenic nerve injury.
Ineffective ventilation Increased work of
breathing
- Decreased ventilatory drive Abdominal distension
Sedation Lower airway obstruction
Brainstem dysfunction Circulatory failure
Metabolic alkalosis Fever
- Vgentilator pump failure Metabolic acidosis
Muscle weakness Other system disease
Prolonged paralysis Circulatory failure.