Neonatal Non-Invasive Respiratory Support: - PowerPoint Presentation

Slide1

Neonatal Non-Invasive Respiratory Support: Overview and Challenges

Jeffrey S. Gerdes, MD, MBAAssociate Chair, Department of PediatricsChildren’s Hospital of PhiladelphiaAssociate Professor, Perelman School of MedicineEmidio M. Sivieri, MSEResearch Bioengineer, CHOP Newborn Care at Pennsylvania HospitalSlide2
Slide3

Why Non-Invasive Support?Airway distending pressure to maintain FRC is the cornerstone upon which all other support modalities are built

Less Chronic Lung DiseaseFewer airway complicationsFewer InfectionsReduced inflammationLess stress for babies, families, and staffLower costSlide4

Increasing HFNC UseAll Patients during NICU Stay

Courtesy of Dr. Reese Clark, Pediatrix

All Patients during NICU StaySlide5

NIPPV

SiPapNAVANCPAPNIV using RAM Cannula

HFONC

??????????????????

HFNC

Question

of the day

Mechanisms of Action

Physiologic Rationale

Challenges for Clinical ResearchSlide6

Nasal CPAP: Physiologic RationaleDistending pressure recruits lung volume

Increases and stabilizes FRCSplints upper airways and compliant chest wallImproves lung ComplianceReduces airway ResistanceDecreases Work of BreathingImproves gas exchangeReduces apneaSlide7

NCPAP: Mechanisms of Delivery

Constant flow: flow opposition (conventional vent)Constant flow: liquid seal (bubble)Variable flow: “fluidic flip” (Infant Flow)Patient expiratory flow opposes system flow and an expiratory resistor valve

Expiratory limb submerged in liquid, with oscillatory nature

Inspiratory and expiratory flow compensation via fluidics engineeringSlide8

All NCPAP devices are not created equal

Variable flow reduces WOB compared to conventional vent CPAP (Lipsten et al, J Perinatol 2005)Variable flow may compensate better for mouth or seal leakageBubble oscillations may improve lung recruitment (Pillow et al, Am J Crit Care Med 2007)Bubble CPAP pressure delivery is flow dependent and not reliably delivered relative to liquid depth (Kahn et al, Pediatr Res 2007)Bubble CPAP pressure delivery varies more than variable flow CPAP (Kahn et al, Pediatr 2008)Nasal interfaces vary in resistance to flow (DePaoli et al, Arch Dis Child Fetal Neonatal Ed 2002)

Variable safety regarding alarms and expiratory limb obstruction risk

Examples:Slide9

at 6 L/minPressure-drop across prongs - by manufacturer

RAM (micro-preemie )

RAM (preemie)

RAM (Newborn)

Modified from: De Paoli, Morley, Davis et al. Arch Dis Child Neonatal Ed 2002

(All at 6 L/min Flow)

0

2

4

6

8

21

Pressure drop

(cmH

2

O)Slide10

Effect of mouth leak

3

4

5

6

7

8

8

7

6

5

4

3

2

1

0

Set CPAP

(cm H

2

O)

Pharyngeal pressure

(cm H

2

O)

De Paoli, et al. Arch Dis Child Neonatal Ed 2005Slide11

4

6

8

Bubble Bias Flow

(L/min)

Mean Pressure

(±SD)

(cm H

2

O)

2

10

12

Set CPAP

Bubble CPAP vs. CPAP with Mech. Ventilator

Kahn, Habib, Courtney, Pediatrics 2008

Bubble CPAP pressure is

flow dependent

Bubble CPAP

Ventilator

No Leak

12

10

8

6

4

8

4Slide12

Clinical Correlations of different CPAP Drivers and InterfacesClinical studies often do not offer clear actionable results

Do mechanistic differences matter, or have they not been discoverable with current studies?Babies have widely variable pathophysiology and severity of illnessDo the large pragmatic trials of NIRS strategies deliver specific answers for relative efficacy when the “gold standard” of CPAP is delivered with widely divergent modalities?Slide13

NIPPV or SNIPPV: Physiologic Rationale

Benefits of NCPAP + additional tidal ventilation and/or lung recruitment from higher MAPMay reduce WOB relative to CPAP (Aghai et al, Pediatr Pulmonol 2006; Chang et al, Ped Res 2011) Airway pressures actually delivered vary considerably from settings (Owen et al, Arch Dis Child Fetal Neonat Ed. 2010 )Is variable pressure delivery favorable to lung function?Is apnea Improved through cyclic receptor stimulation?Synchronization may improve efficacyUnclear if NIPPV or bi-level CPAP is more efficacious (Roberts et al, Pediatrics 2013)Are these modalities “Super CPAP”?Slide14

Heated and Humidified High Flow Nasal CannulaSlide15

HFNC: Mechanisms of ActionGas Conditioning EffectsFlow EffectsPressure EffectsSlide16

HFNC: Mechanisms of Action

Gas Conditioning Effects

Reduces patient’s metabolic workload needed for Heating and Humidifying

(Waugh et al, Granger, RespCare 2004)

Improves mechanics

- H&H Increases Compliance and Conductance

(Greenspan et al, J

Peds

1991) Slide17

HFNC: Mechanisms of Action

Flow Effects

Improves lung mechanicsReduced inspiratory resistance => Reduced resistive Work of Breathing

(Saslow et al, J Perinatol 2006)Expiration: possible “Coanda”

effect

(Dysart et al, Resp Med 2009)

Washout of Nasopharyngeal dead space => Improved gas exchange

(Frizzola et al, Pediatr Pulm 2011)

As flow increases, CO

2

elimination > increase in MAP Analogous to Trans Tracheal Catheter TGI

Slide18

Washout of anatomical dead space

Continuous flow washes out the upper airways and leads to improved oxygenation Reservoir of fresh gas in upper airwayAvoids rebreathing of high-CO2 gas in dead spaceSchibler et al, Int Care Med 2011Courtesy of Walsh et al, Resp Care 2009

Nasal cannula

Proposed flushing of

dead space at higher flows

Washout of nasopharyngeal cavity

Washout

flow exiting

the mouthSlide19

HFNC: Mechanisms of ActionPressure Effects

HFNC has been shown to provide positive distending pressureHighly dependent on prong-to-nares diameter ratio and degree of mouth closure (Locke et al, Pediatrics 1993; Sivieri et al, Pediatr Pulm 2013)Slide20

74%

68%

55%

44%

36%

Intra-cannula

pressure (74% occl.)

Pressure Limiting Safety Valve opens

Percent

Occlusion

74%

68%

55%

44%

36%

Percent

Occlusion

100%

86%

Mouth Fully Closed

Mouth Fully Open

HFNC Pressure Delivery:

Effect of flow rate, % nares

occlusion,

and

mouth leak

Sivieri, Gerdes, Abbasi. Pediatr. Pulm. 2013Slide21

HFNC delivered pressure

Pharyngeal Pressure

(cmH

2O)Flow 2 Lpm

Flow 4 Lpm

Flow 6 Lpm

1 minute

Wilkinson et al, J Perinatol 2008Slide22

Causes of variability of delivery of HFNC% nasal occlusion by catheter Characteristics of catheter design

Characteristics of gas conditioning with heat and humidityMouth leakVariability in disease state of the patientSlide23

RAM CannulaTM

(Neotech Products)Soft nasal prong interface, relatively large IDFDA approved as a Class I medical device, as a nasal cannula for delivering oxygen: CPAP interfaces are Class 2 Medical Devices3 sizes: micro-preemie (ID 2.0 ,OD 2.7), preemie (ID 2.0, OD 2.9), newborn (ID 2.5, OD 3.1 )“Expiratory limb” much smaller diameter than CPAP interfacesRecommended % nasal occlusion: 60-80%Connector attaches to standard ventilator tubingHas been used to deliver CPAP, NIMV, HFONVSlide24

RAM Cannula

TM (Neotech Products)Slide25

RAM CannulaTM

(Neotech Products)Soft nasal prong interface, relatively large IDFDA approved as a Class I medical device, as a nasal cannula for delivering oxygen: CPAP interfaces are Class 2 Medical Devices3 sizes: micro-preemie (ID 2.0 ,OD 2.7), preemie (ID 2.0, OD 2.9), newborn (ID 2.5, OD 3.1 )“Expiratory limb” much smaller diameter than CPAP interfacesRecommended % nasal occlusion: 60-80%Connector attaches to standard ventilator tubingHas been used to deliver CPAP, NIMV, HFONVSlide26

`

100%

100%

78%

60%

48%

38%

Percent Occlusion

Mouth Fully Closed

Mouth Fully Open

RAM Cannula Pressure Delivery:

Bench Test

Gerdes, Sivieri, Abbasi, EAPS Congress 2014

Dräger BabyFlow M prongs 4.5mm O.D.

RAM Preemie Cannula 3.1 mmO.D. prongs

Nares

I.D.Slide27

RAM Cannula used for “NCPAP”

In bench tests, RAM cannula interface delivers 60% less than the MAP set on the ventilator, even with mouth closedWith mouth open, delivered MAP is further reducedBy design, RAM cannula is neither NCPAP nor HFNCUsing 60-80% nares occlusion does not provide sufficient seal to deliver CPAP.Due caution should be applied if using RAM cannula interface to provide CPAP, pending further studies and classification as a Class II Medical DeviceSlide28

Nasal High Frequency Ventilation

Initial pCO

2

Final pCO

2

2 hours NHFV

pCO

2

(mm Hg)

75

70

65

60

55

50

45

40

35

30

Colaizy

et al,

Acta

Paediatr

. 200

Infant Star,

Single Nasopharyngeal tube

Frequency 10Hz

Amplitude 50

torr

n=14 Infants

GA 27 (25-30) wks

BW 1.6 (1.1-2.9) kg

p = 0.011Slide29

NIPPV

SiPapNAVANCPAPNIV using RAM Cannula

HFONC

Mechanisms of Action

Physiologic Rationale

Challenges for Clinical Research

Does it matter which NIRS strategy is used in a given patient or NICU?

HFNC

Question

of the daySlide30

Pulmonary Factors to Consider When Evaluating NIRS Systems

Physiologic mechanisms imply that: - NCPAP/NIPPV might be better for lung recruitment- HFNC might be better for CO2 retention- NIPPV might be better for apneaAre we reasonably able to study these differences, And are these differences clinically important?BUTSlide31

Extra-pulmonary Factors to Consider When Evaluating NIRS Systems

Minimizing nasal septal injuryEase of nursing and respiratory therapy careComfort for baby and familyNoise pollutionPromotion of infant developmentCost –interface and disposables, amortized cost of the driver, RRT and RN time, and possible impacts on length of stay or severity of illnessSlide32

NIRS: Summary and Challenges for this conferenceNCPAP, NIPPV, and HFNC all have physiologic rationales and feasible mechanisms of action

All provide varying degrees of respiratory support which improve physiologic parameters and gas exchange in neonatesLittle is known about which devices may be better for different patho-physiologies or different severities of illnessDo the clinical trials have sufficient numbers or stratification of diagnoses and severity of illness to differentiate the utility of these modalities? OR,Slide33

Are we left with the current state in which clinicians apply well-studied, safe NIRS techniques according to unit or provider preference, matching the device to the baby’s needs, and response to therapy?Are “more randomized trials” the answer, or should we steer towards other research methodologies?

NIRS: Summary and Challenges for this conference