Infant Mechanical Ventilation: The Clinical Implications of the Latest Research

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Infant Mechanical Ventilation The Clinical
Implications of the Latest Research

• Rob DiBlasi RRT, NPS
• Clinical Research Coordinator
• Seattle Childrens Hospital Research Institute

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Objectives

• Provide the RCP with
• A history on infant ventilation
• An update in technological improvements
• A description of modes of ventilation and how
  they have impacted the research
• Evidence based disease specific management
  strategies for
• RDS, PIE, BPD, MAS, PPHN, and CDH

Seattle Childrens Hospital Research Institute
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What I am about to tell you
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Too much bacon 'bad for lungs'
A Columbia University team found people who ate
cured meats at least 14 times a month were more
likely to have COPD
cured meat consumption was inversely associated
with FEV1 and FEV1/FVC but not FVC
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Amillia Sonja Taylor

• Birth Weight 283 grams
• Length 10 inches
• Gestational Age 22 weeks
• Hospital LOS 4 months
• Oxygen Req. Low
• Home w/o deficit PRICELESS

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3,000 Years and Going Strong
1806 Chaussier described experiments with the
intubation and mouth to tube resuscitation of
stillborn infants
Old Testament, Elijiah, I Kings 1717
1970-1980 IMV- Bourns LS104, Baby Bird,
Sechrist ventilators used with intubated infants
And he went up, and lay upon the child and, put
his mouth upon his mouth, and his eyes upon his
eyes, and his hands upon his hands and he
stretched himself upon the child and the flesh
waxed warm
1990-2006 Surfactant, HFOV, partial liquid lung
ventilation, volume targeted ventilation, and
pulmonary graphics
1493-1541 Paraclesus reported the use of bellows
and an oral tube
1950 Polio era attempts made at NIPPV in infants
400 BC Hippocrates was the first investigator to
record his experience with intubation of the
trachea
1879 aerophore pulmonaire was developed for short
term ventilation of newborn infants
1980s Microprocessor controlled, SIMV Bear
Cub, Bird VIP, and Servos
1667 simple forms of continuous and regular
ventilation had been developed by Vesalius
1963 Patrick Kennedy born prematurely was treated
with hyperbaric chamber and died two days later
from RDS
About all that can be done for a victim of
hyaline membrane disease is to monitor the
infants blood chemistry and try to keep it near
normal level The New York Times
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Intermittent Mandatory Ventilation- TCPL
Patient
Patient
Exhalation
Inspiration

• Fixed flow creates increased WOB
• Mechanical breaths delivered based on time
  despite patient effort Asynchrony results in
  hypercarbia, breath- stacking, air leak, IVH and
  a greater need for sedation and paralytics

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Technological Advancements

• Rapid response times (PTV)
• Active expiratory valves
• Accuracy of delivered volumes
• Volume targeted ventilation
• Proximal flow sensing
• Volume, triggering at ET tube, graphics
• Pulmonary graphics
• Identify various problems of the
  patient-ventilator system

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Patient Triggered Ventilation- SIMV and A/C
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Flow Synchronized Ventilation

• Patient initiated, patient terminated breath
  type
• "captures" patient-ventilator synchrony by
  varying TI
• Eliminates "breath hold" due to inappropriately
  set Ti
• Improves gas exchange
• Reduces the amount of sedation given
• Significantly reduces weaning duration and time
  to extubation

Donn et al, Journal of Perinatology Vol 24,
No.2,1994
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Dual Control- Hybrid Modes

• Dual control mode of ventilation where the
  ventilator internally controls pressure in order
  to achieve a minimum target tidal volume
• Manipulates flow to deliver the lowest peak
  inspiratory pressure
• Has a variable flow system unlike traditional VCV
  
• Pressure will vary from breath to breath
  depending on the patients lung compliance and
  resistance
• Pressure Regulated Volume Control (PRVC)
• Volume Guarantee (VG)
• Machine Volume (MV) Dual Control within the
  Breath

Worsening Compliance
Improving Compliance
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Dual Control- Hybrid Modes

• Advantages
• Variable flow system
• Auto-regulation of PIP
• Provides a target VT which may ? VILI after
  surfactant administration
• May reduce the incidence of hypocarbia and PVL
• Reduces the number of ABGs obtained

• Disadvantages
• Breath to breath volume variability
• Difficult to use in leaky systems
• May ? support significantly during the weaning
  phase and lead to high WOB, atelectasis, and
  failure to wean

McNallion et al. Arch Dis Child 200590865-870
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Volume Targeted/ Dual Control Ventilation RCTs in
Preemies
Author n Modes
VT (ml/kg) Mortality Complications
Outcomes

• Sinha et al 50 VC vs. TCPL
  5-8 NS NS (1997)
  (gt1200 g)
• Olsen et al 14 PSVG vs.
  5 NS NS
• SIMV PC
• Suhas et al 34 PSVG vs.
  5 NS NS
• (2005) SIMV PC
• D'angio 213 PRVC vs. NM
  NS NS
  (2005) SIMV PC
• Donn et al 80 VC vs. TCPL 4-6
  NS NS
• (2006)

NS -not
clinically significant
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• "The tedious argument about the virtues of
  respirators not invented over those readily
  available can be ended now that it is abundantly
  clear that the success of such apparatus depends
  on the skill with which it is used"
  Lancet 21227, 1965

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Approaches to Infant Ventilation
LOVE- Laws of Ventilator Efficiency

• Know thy ventilator and disease pathology
• Develop a specific strategy for the
  pathophysiology in each individual patient
• Change the ventilatory strategy as the
  pathophysiology changes
• Always strive to wean the patient off of
  ventilatory assistance

Assisted Ventilation of the Neonate 4th Ed.
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Ventilator Strategies- RDS

• Volume Targeted Ventilation or Pressure Control
  to keep VT at 4-6 ml/kg range
• Inspiratory Time- gestational age
• Rapid Respiratory Rates (60-70 bpm)
• PEEP 3-5 cmH20
• ABG PH 7.20-7.25 PaCO2 40-55 PaO2 50-70
• Surfactant- get them open, get them breathing and
  get them off!
• Wean directly to NCPAP- ASAP
• Attempts at avoiding ROP in patient lt 40 weeks

HFOV- MAP 16 initially or 2-4 higher than MAP on
CV, AMP Power 2 or good shake, HZ 12-15 IT 33
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Graphical Analysis of RDS
Pre Survanta
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PEEP

• Atelectrauma due to repetitive opening and
  closing of diseased lung units and terminal
  bronchioles can lead to shear injury and
  worsening lung disease
• RCTS using open lung strategies using high(er)
  levels of PEEP to stabilize alveoli during infant
  ventilation needs to be done

Van Kaam et al. Crit Care Med 2007 Vol.35, No.3
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Graphical Analysis of RDS
Eight hours post Survanta x 2
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Pressure versus Volume

• Evidence suggests that pulmonary overdistension
  from volutrauma rather than barotrauma, is the
  critical determinant of VILI, followed closely by
  atelectrauma
• Infants are at a much greater risk for VILI
  because their chest walls are more compliant than
  children or adults and incapable of limiting
  inflation
• We believe the optimal VT for infants is
  somewhere between 4 and 8 ml/kg!
• VLBW- 4-6 ml/kg
• All other infants- 5-7 ml/kg

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Ventilator Induced Lung Injury
Mathay et al, NEJM, 2000
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Ventilator Strategies- RDS
-30 Preemies 2532 weeks with acute RDS -Randomly
assigned to be ventilated with Vt 5ml/kg or Vt 3
ml/kg -Proinflammatory cytokines (interleukin-6
(IL-6), interleukin-8 (IL-8), and TNF were
determined in the tracheal aspirate on 1, 3, and
7 days of life
Pediatric Pulmonology 37510514 (2004)
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• " Mouth to mouth resuscitation may be better than
  using a mechanical bellows to inflate the lung
  becausethe lungs of one man may bear, without
  injury, as great as those of a man can exert,
  which by the bellows can not always be
  determined"
• J Philos Trans Royal Society, 1745

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HFOV versus Conventional Ventilation

• 500 VLBW (600-1200g) infants randomized to either
  HFOV or VCV (VT 4-7 ml/kg)
• Infants in HFOV group
• were successfully extubated earlier than SIMV
  (plt0.001)
• were more likely than those treated with SIMV to
  be alive without requiring supplemental oxygen at
  36 weeks of postmenstrual age (p0.046)
• No differences in neurological complications
  between the two groups
• For every 11 infants treated with high frequency
  oscillatory ventilation, 1 death or 1 case of
  chronic lung disease was prevented

Courtney et al. The Neonatal Ventilation Study
Group. N Engl J Med, Vol. 347, No. 9
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HFOV versus Volume Guarantee Ventilation

• 25 Infants at less than 30 weeks GA with RDS
• HFOV13
• PSVG (5 ml/kg) 12
• HFOV is associated with a reduction of lung
  inflammation in comparison with VG in preterm
  infants with RDS

Carlo Dani et al. Pediatr Pulmonol. 2006
Mar41(3)242-9
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Normal Lungs on Conventional Ventilation
Oleic Acid Induced Lung Injury- Overdistension
Oleic Acid Induced Lung Injury- atelectasis
Oleic Acid Induced Lung Injury- HFOV
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Early vs. Delayed Extubation

• 125 day premature baboon model of BPD treated
  with prenatal steroids and 2 doses of surfactant
• EnCPAP group extubated at 24 hours to Nasal CPAP
• DnCPAP group extubated at 5 days ventilated with
  CV 4-6 ml/kg with permissive hypercapnea and PaO2
  55-75

Coalson et al. Pediatrics 20061182038-2050
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125 Day Control (27 Weeks)
185 Day Control (40 Weeks)
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Take Home Message

• Prolonged ventilation and reintubation in
  preemies can lead to
• pulmonary growth arrest
• decreased alveolarization
• decreased vascularization
• Other complications
• PDA, Sepsis, infection and hyperoxia

Coalson et al. Pediatrics 20061182038-2050
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Inhaled Nitric Oxide in the Preemie

• Inhaled NO improves the pulmonary outcome for
  premature infants at risk for BPD
• Improved survival without chronic lung disease
  (P0.042)
• Improvements in pulmonary mechanics
• Improvement in pulmonary function and alters lung
  growth and alveolarization

No CLD Study Group. NEJM 3554.July 27 2006
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Summary-RDS

• Significant decrease in mortality with VLBW
  infants in the last two decades
• Significant morbidities associated with
  prematurity and mechanical ventilation are
  occurring more frequently
• There is no consensus regarding an optimal
  ventilator strategy for the support of the
  preterm newborn
• Standardization of ventilator management and
  general patient care may have a greater impact on
  the outcome than the ventilator mode
• It is not so important that we do the right thing
  but that we do the same thing
• Initial studies support early liberation from
  mechanical ventilation in order to avoid cycling
  of the lung

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Airleak- PIE

• Positional Therapy
• ventilate patient with affected side down
• Minimize PIP and VT
• Short TI
• Heliox
• Selective intubation of the unaffected side
• HFOV
• Jet ventilation
• Accept lower PaO2 with permissive hypercapnea

HFOV- MAP start 1-2 less than CV
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Ventilator Strategies- BPD

• Volume targeted modes- PRVC
• helpful to maintain adequate ventilation due to
  fluid shifts, mucous plugs and migratory
  atelectasis
• Volume target may have to be higher (10-12 ml/kg)
  in order to ventilate due to floppy airways
• Adjust TI to avoid gas trapping, allow patient to
  determine their own inspiratory time- PSV
• Maintain good oxygenation and ventilation to
  minimize effects of pulmonary hypertension
• Specialty gases
• Nitric Oxide and Heliox
• ABG 7.25-7.30 PaCO2 55 PaO2 50-70

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Tracheal Malacia
-14 Premature lambs - 7 Ventilated PIP/PEEP 35/5
cmH2O 40 breaths/min) - 7 Non-ventilated -4
hours -MV results in dimensional alterations that
increased anatomical dead space and reduced
static and dynamic elastance of the neonatal
trachea
Pediatric Pulmonology 42141149 2007
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BPD Spells
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BPD Spells
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Meconium Aspiration Syndrome

• Low pressure, low volume (5-7 ml/kg) fast RR,
  Lower TI and PEEP 3-4 cmH20
• Usually term or post term kids so hyperoxia wont
  hurt ABG PH 7.3-7.4 PaCO2 40-50, PaO2 60-80
  torr higher if needed
• Sedation and paralytics will decrease gas
  trapping
• NO, Surfactant, and ECMO with OIgt 40

HFOV- MAP 2-4 higher than CV, AMP power 2.5,
Hz start at 10 (will need to go down to 6)
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PPHN

• Lungs usually very healthy
• Decrease pulmonary vasoconstriction and improve
  pulmonary blood flow
• Always measure pre and post ductal SPO2
• Keep PaO2 greater than 100
• Mild hyperventilation for alkalosis 30-40 mmHg
  (PH 7.4-7.5)
• PaCO2 20-25 decrease cerebral blood flow
• High VE requirements may promote VILI
• HFOV
• ECMO

1 lpm
2 lpm
Pressure in pulmonary arterial system exceeds
systemic pressure
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CDH
Courtesy of Dr. Charles Stolar
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Ventilation in CDH

• High frequency positive pressure ventilation
• embraces spontaneous breathing, permissive
  hypercapnea, and elective surgery
• Conventional low rate- initial approach
• IMV 40, PIP 20, PEEP 5, TI 0.5 s
• HFPPV- Tachypnea, retractions, preductal SPO2lt80
• IMV 100, PIP 20 (limit 25), PEEP 0, TI 0.3 s
• PaCO260-65 and preductal SPO2 80-95
• 120 infants with CDH were treated with HFPPV
• Surgery performed when pre and postductal SPO2
  were stablized
• Overall survival rate was 75.8
• 13.3 patients were treated with ECMO

Stolar et al Journal of Pediatric Surgery March
2002
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The Future
Closed loop FiO2
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Questions?