CPAP fell out of favor in some centers after the development of infant ventilators. Concerns about ventilator-induced lung injury and the continued high incidence of chronic lung disease, coupled with the high profile given to CPAP by Columbia (in NY, not South America) have led to a CPAP comeback.
You’ve Seen This Before
If insufficient CPAP is used, the lung is not “open” and is subject to mechanical stress and inflammatory response just like with mechanical ventilation. CPAP on high FiO 2 (indicating atelectasis) may be worse than intubation, surfactant administration and lung protective ventilation
Methods of Delivering CPAP
Short Nasal Prongs
Long Nasal Prongs
Variable Flow (Fluidic)
?Oscillation causes ventilation
Easy and available
More stable CPAP Pressures
Lowest Work of Breathing
Bubble, Bubble, Boil and Trouble
What do we know about Bubble NCPAP?
Columbia in NYC likes it.
Bubble data: The world’s literature on bubble CPAP consists of 3 small studies
Lee et al, A comparison of underwater bubble CPAP with ventilator-derived CPAP in premature neonates ready for extubation. Biol Neonate , 1998
- 10 infants, crossover design
CPAP given with ETT
bubble group showed decrease in minute volume and reduction in respiratory rate
Pillow and Travadi, Bubble CPAP: Is the noise important? Pediatric Research 2005
Bench study; decreasing compliance of lung model increased magnitude and frequency content of pressure oscillations
Bubbling may enhance lung volume recruitment
Liptsen et al, Bubble CPAP vs Infant Flow, J Perinatology 2005
18 infants, each infant was his own control, order of devices randomized
Resistive WOB, resp rate, phase angle all greater with bubble compared to IF.
Current study underway: bubble vs conventional NCPAP.
Bubble NCPAP appears similar to other forms of continuous-flow NCPAP. It is unclear whether the “bubbling” does anything
More labored and asynchronous breathing is seen with bubble NCPAP compared to variable-flow NCPAP
But…. More data are needed
What is Variable-Flow NCPAP? A child with a very disturbed family life.
Stay tuned for the sequel…………..
Who is this kid, anyway?
Pressure supplies a jet flow, direction in response to pressures generated by the patient.
On inspiration, the jet flows towards the nasal cavity, assisting in inspiration
On exhalation, pressure in the nasal cavity the jet flows down the expiratory branch.
Switching of high pressure control flow from inhalation to exhalation (“fluidic flip”) allows the device to follow the baby’s breathing from inhalation to exhalation, decreasing the work of breathing.
Moa G, Nilsson K, Zetterstrom H, Jonsson L. Critical Care Medicine 1988;16:1238
Who is this kid, anyway? Childs, Neonatal Intensive Care, 2000
Is All NCPAP Created Equal?
Controlled clinical trials: Physiologic data
Courtney, Habib et al : Lung recruitment and breathing pattern during variable vs continuous flow NCPAP in premature infants: An evaluation of three devices. Pediatrics 2001
Pandit, Courtney, Habib et al : Work of breathing during constant and variable flow NCPAP in preterm neonates. Pediatrics 2001
Courtney, Habib et al : Changes in lung volume and work of breathing: A comparison of two variable flow NCPAP devices in VLBW infants. Pediatric Pulmonology 2003
Bottom Line: WOB less, lung recruitment better with variable-flow.
Is All NCPAP Created Equal? Controlled clinical trials: Clinical data Stefanescu B, Murphy P, Hansell B, Fuloria M, Morgan, T, Aschner J: Pediatrics 2003;112:1031 162 infants < 1000gm randomized at extubation
Extubation Failure Stefanescu et al, Pediatrics 2003;112:1031
Kaplan – Meier curve depicting the time course of extubation failure within the first 7 days (168 hours) Stefanescu et al, Pediatrics 2003;112:1031
Bottom Line: No difference. Why?
?? Documented improved recruitment and decreased WOB with variable-flow not clinically important ??
?? Single-center bias ??
?? Some other reason ??
Reasons for Extubation Failure Stefanescu et al, Pediatrics 2003;112:1031
Cochrane Review, 2002 Devices and pressure sources for administration of NCPAP in preterm infants Conclusions: “ Short binasal prong devices are more effective than single prongs in reducing the rate of re-intubation. Although the Infant Flow Driver appears more effective than the Medicorp prongs the most effective short binasal prong device remains to be determined. The improvement in respiratory parameters with short binasal prongs suggests they are more effective than nasopharyngeal CPAP in the treatment of early RDS. Further studies incorporating longer-term outcomes are required. Studies are also needed to determine the optimal pressure source for the delivery of NCPAP.”
Are there any advantages of bubble NCPAP when compared to conventional continuous-flow NCPAP?
Over the long term, is any one form of NCPAP more advantageous than any other?
Is non-invasive ventilation combined with NCPAP advantageous? Is it safe?
Are “new and improved” ways to provide NCPAP such as SiPAP any “better”?
… .VF Family Court: THE SEQUEL The Godfather, Viasys, intervenes. EME and SM get back together (sob!!) and merge (oh my!) And a little sister is born, SiPAP!!
Provides bi-level CPAP
“ Sighs” 2-3cmH 2 O above the set CPAP level, time of the sighs and rate of sighs can be varied.
MAY stimulate respiratory center, recruit unstable alveoli, decrease work of breathing.
World Literature on SiPAP Long JA, Courtney SE: Bilevel Continuous Positive Airway Pressure (SiPAP) in Extremely Low Birth Weight Infants: An Observational Study of a New Device. Pediatr Res 2005: 3410A 9 infants 5 extubated successfully to SiPAP 3 reintubated for severe apnea 1 developed a pneumothorax while on SiPAP*****
SiPAP: Hot off the press Migliori et al, Pediatric Pulmonology Sept 2005: Nasal bilevel vs. continuous positive airway pressure in preterm infants 20 babies, mean study weight 1kg, received 2 cycles of CPAP alternated with 2 cycles of bilevel CPAP, each phase lasted one hour. Oxygen saturation and tcO 2 increased, and tcCO 2 and respiratory rate decreased during the bilevel CPAP periods.
“In my experience……” “… .a phrase that usually introduces a statement of rank prejudice or bias. The information that follows it cannot be checked, nor has it been subjected to any analysis other than some vague tally in the speaker’s memory.” -Dr. Michael Crichton
SiPAP Observations/Recommendations More data are needed Seems to work in some very little babies For extubation, seems to work better if you start at a higher sigh rate and work down rather than a low sigh rate and work up SiPAP is NOT nasal IMV. Use the term “sigh” not “breath” Keep sigh time at one second. Make sure you’re not overdistending on xray We are starting a work of breathing study soon. Did I say that more data are needed?
Nasal IMV Available literature predominantly done with synchronized IMV on the old Infant Star. Cochrane reviews of these data suggest decreased apnea and need for reintubation; work of breathing appears to be decreased. BUT – most NIMV today is not synchronized, because few people have the old Stars anymore. AND – there is little data on non-synchronized NIMV. Nasal IMV is popular despite limited data. PS – SiPAP is NOT nasal IMV!!!!
Vapotherm More popular than McDonald’s Data, data, where are the data?
World’s Literature on Vapotherm: 4 abstracts at SPR 2005 Chang GY, Cox CC, Shaffer TH: Nasal cannula, CPAP, and Vapotherm: Effect of flow on temperature, humidity, pressure and resistance Bench study Temperature/humidity were very close with Vapotherm and IF NCPAP. Pressure/resistance at cannula with Vapotherm VERY high.
Vapotherm World Lit (cont) Saslow et al : Work of breathing during Vapotherm vs NCPAP for the treatment of RDS Conventional NCPAP at 4 cmH 2 O vs Vapotherm at 3-5 lpm. No differences Ramanathan A et al : High flow nasal cannula use in preterm and term newborns admitted to NICU: A prospective, observational study Vapotherm used in 64 infants, max 6 lpm, babies did well. Nair G, Karma P : Comparison of the effects of vapotherm and NCPAP in respiratory distress in preterm infants. 28 infants, ?CPAP level, ?Vapo flows. No differences
Thoughts on Vapotherm More data urgently needed PROBABLY ok up to about 6 lpm, likely providing about 5cmH 2 O NCPAP at that level Should not be used at higher flows until more data on WOB and NCPAP provided are available.
Great unknown of the universe: Why do neonatologists continue to do stuff without data even though they know better?
Trends in Mechanical Ventilation
Tidal volume, tidal volume, tidal volume
Support the patient’s own breaths
Sicker patients – not the same thing as “rescue”!!
Extubate from HFOV
Transcutaneous Monitoring - Back to the Future
The Fall from Grace of Tc Monitoring
Onset of pulse oximetry
Why We Need to Resurrect Tc Monitoring – Especially for CO 2
No good way to continuously monitor CO 2 in infants – new end-tidal machines may be another way
New Tc monitors easy to use
No need to heat the sensor for TcCO 2 , so no skin burns
New technology can cause rapid, dangerous swings in PaCO 2
Why We Need to Resurrect Tc Monitoring – Especially for CO 2
Strong evidence that overventilation is damaging to the lungs and other organs
Concerning evidence that very low PaCO 2 may cause brain damage in the preterm infant.
Why We Need to Resurrect Tc Monitoring – Especially for CO 2 New data raises concerns about brain damage from HYPERCARBIA “ Permissive hypercarbia” has never defined, and has never been shown to be safe in the newborn.
Important Points to Remember
Transcutaneous CO 2 monitors measure the CO 2 tension at the surface of the skin. This is not the same thing as the PCO 2 in the arterial blood, but the TcCO 2 and the PaCO 2 correlate.
This means that when the PaCO 2 goes up, the TcCO 2 goes up, and when the PaCO 2 goes down, the TcCO 2 goes down.
Important Points to Remember
Thus, though the PaCO 2 and the TcCO 2 numbers may not be the same, the trend is seldom wrong.
Edema, poor perfusion, and increased skin thickness will increase the TcCO 2 but the trend with the PaCO 2 will still be there.
Important NICU Applications
Initiation of HFOV
Critical infants with fluctuations in ABGs
Diagnosis of pneumothorax
Recommendation for TcCO 2 Use
Apply on trunk; abdomen or lower back best
Calibrate at 40 degrees C.
Change site every 6 hours
Not much can go wrong with the monitor – learn to troubleshoot.
Tc Monitor Test
The Tc alarm goes off. You should:
Increase the alarm limits
Turn alarms off
Remove machine from patient, it obviously isn’t working
Check the patient and get a gas if necessary
Fun New Stuff You May Be Hearing About
Use of iNO in Preterm Infants
Additional Surfactant to Prevent/Lessen BPD
Jet Ventilation to Lessen BPD Severity
When in doubt, let the kid make his own damn vent changes!!