Nasal Cannula Intermittent Mandatory Ventilation (NC-IMV)

Introduction With increased survival of very low birth weight (VLBW) infants, the number of infants who require prolonged mechanical ventilation (MV) has increased The pulmonary management of these infants is directed at minimizing the need for prolonged MV to reduce ventilator-induced trauma and oxygen toxicity Early extubation often presents difficulties because of upper-airway instability, poor respiratory drive, alveolar atelectasis, and residual lung damage Khalaf et al Pediatrics 2001; 108:13-17

Background Use of Nasal respiratory support (NARES) is on the rise to decrease post-extubation failures, bronchopulmonary dysplasia (BPD), and for the treatment of apnea of prematurity CPAP, by various means, commonly is used to wean premature infants from mechanical ventilation

NCPAP Failure Rates NCPAP use is associated with failure rates of 20 to 80% in preterm infants Reasons for failure include recurrent apnea/ bradycardia/desaturations or respiratory acidosis requiring intubation or re-intubation Ramanathan et al J Perinatol October 2010; 30:S67-S72

Background The addition of a back-up rate by using NIPPV not only adds intermittent distending pressure above PEEP but also increases flow delivery in the upper airway Friedlich et al J Perinatol 1999; 19:413-418 Barrington et al Pediatrics 2001; 107:638-641

NCPAP vs. NIPPV for NARES Additionally, NIPPV has been shown to decrease NCPAP failure rates to 5 -20%

Background Typical nasal interfaces used: Short bi-nasal prongs Inca prongs or Argyle Prongs Nasopharyngeal prongs Nasal mask with SiPAP machine Variable flow devices Infant Flow Drivers with nasal prongs or nasal mask. Problems with these nasal interfaces Cumbersome Mucosal irritation, bleeding, nasal trauma Obstruction due to secretions in the nose or nasopharynx

Background High flow nasal cannula systems are increasingly adopted because of the ease of use Vapotherm, Fisher Paykel HFNC However, these HFNC systems have no ability to measure or limit the pressure delivered to the baby There are no pop-off valves in these systems Only pop-off is at 20 PSI to protect the device and not to protect the baby Can generate significant amount of distending pressures at the nasal interface Air leaks have been reported

Indications To facilitate extubation of mechanically ventilated neonates As a primary mode of support for neonates with respiratory distress Infants with moderate-to-severe apnea

Materials We use a time-cycled pressure and flow limited (TCPFL) intermittent mandatory ventilation via nasal cannula (NC-IMV) This system gives us the ability to control pressure and flow rate with the use of nasal cannula while safely delivering rate, PIP, PEEP and limit the flow rate to 6 or 7 LPM

Materials Nasal cannula-short tubing Connected to larger adapter Larger circuit Same humidity, but heating at 40°C

Materials

NC-IMV Set-Up Set up: Conventional Ventilator (Viasys) Mode: Time Cycled Pressure Limited SIMV mode (TCPL-SIMV) Reason: To allow us to be able to control the flow rate. Flow Rate: 6 LPM if using Neonatal size Nasal cannula 7 LPM if using Infant size Nasal cannula IMV rate: started at a maximum of 40 bpm PIP: Same as the most recent Conventional Ventilator PIP (max 30 CmsH2O) PEEP: 5 cmsH2O Insp. Time: 0.5 seconds

NC-IMV Set-Up Select appropriate Nasal cannula according to patient’s size Babies <1Kg Premie NeoTech RAM Nasal Cannula (2.0mm ID) Babies 1-2.5Kg Newborn NeoTech RAM Nasal Cannula (2.5mm ID) Babies >2.5Kg Infant NeoTech RAM Nasal Cannula (3.0mm ID)

Weaning Protocol Wean PIP first Once PIP was around 10, rate was decreased to 10 If infant remained stable, switched to NC-CPAP If infant was stable for 12-24 hours on NC-CPAP, switched to low flow nasal cannula (<2 LPM)

Results: (n=183) 15 (8 %) Range 385 – 4167 23 – 41 109 (60 %) 1 -124 Birth weight (g) 385 – 4167 Gestational Age (weeks) 23 – 41 BW < 1500 g (n) (%) 109 (60 %) Age @ NC-IMV start (days) 1 -124 Duration of NC-IMV (days) 1 - 49 NC-IMV Failures, (%) 15 (8 %) No cases of nasal injury or gastric or ear drum perforation were seen within the 1,168 days of NC-IMV. One pt with pneumothorax. Now have treated >300pts for >3,000 days of NC-IMV Ramanathan R, Andaya S et al, SPR Meetings, Vancouver, May 2010

Previous Studies All infants tolerated NC-IMV All infants tolerated feeds during NC-IMV No cases of nasal injury, or gastric perforation were seen NC-IMV failure rate requiring intubation in our study population was 8%

Conclusion NC-IMV is feasible and well tolerated. TCPFL NC-IMV allows clinicians to limit pressures and can be delivered safely to neonates Therefore, it appears that NC-IMV may be used in facilitating extubation of mechanically ventilated neonates, as a primary mode of support for neonates with respiratory distress, and for the treatment of apnea of prematurity While reducing obstacles such as mucosal irritation, bleeding, nasal trauma, or obstruction due to secretions in the nose or nasopharynx.

A NOVEL MEANS FOR DELIVERING NASAL INTERMITTENT POSITIVE PRESURE VENTILATION IN INFANTS VIA THE NASAL CANNULA (NC): MEASUREMENTS OF DELIVERED PARAMETERS IN A NASAL AIRWAY/LUNG MODEL

NC-IMV Nasal Cannula Intermittent Mandatory Ventilation (NC-IMV) is a novel means of delivering pressure controlled NIPPV breaths noninvasively to neonates requiring respiratory support. We have previously reported that NC-IMV is feasible and well tolerated in a large number of neonates. However, pressures or volume delivered to the patient is not known. Ramanathan et al Pediatric Academic Society, May 2010; Abstract 1472.217

Hypothesis NC-IMV is sufficient to provide measurable ventilation effects and pressure, using 3 different cannula devices, in a lung model using a realistic "leaky” neonatal airway model

Objective To determine the magnitude of pressure and volume delivered to an infant nasal airway/lung model Using different sized nasal cannula At different peak inspiratory pressure (PIP) settings during constant flow, time-cycled, pressure-limited ventilation.

Methods We configured a neonatal test lung to simulate an apneic premature infant (CL:0.8 mL/cmH20; R:75 cmH20/L/sec). A realistic infant nasal airway model was attached to the test lung.

Methods 28 week premature infant airway model that was reconstructed from a head CT scan and a rapid prototyping device

Methods Schematic of Experimental set-up

Methods Set up: Conventional Ventilator (Viasys) Mode: Time Cycled Pressure Limited SIMV mode (TCPL-SIMV) Flow Rate: 7-9 LPM IMV rate: 40 bpm PEEP: 5 cmsH2O Insp. Time: 0.5 seconds The nasal airway was ventilated at PIP of 10, 15, 20, 25, and 30 cmH20

Methods Nasal cannulae used Neonatal nasal cannula (Fisher Paykel, Auckland, NZ): ID 1.5 mm Infant nasal cannula (Fisher Paykel, Auckland, NZ) : ID 1.8 mm New prototype nasal cannula (Neotech Ram Nasal Cannula®) : ID of 3 mm

Fisher Paykel Neonatal Nasal Prongs Results with ID 1.5 mm Results with ID 1.5 mm Fisher Paykel Neonatal Nasal Prongs

Fisher Paykel Infant Nasal Prongs Results with ID 1.8 mm Fisher Paykel Infant Nasal Prongs

Neotech Ram Nasal Cannula® Results with ID 3 mm Results with ID 3 mm Neotech Ram Nasal Cannula®

Results Under all testing conditions, there was detectable PLUNG, VLUNG, and PEEP during NC-IMV. There was a linear relationship between PIP applied by the ventilator and VLUNG/PLUNG up to 30 cmH20.

Results The Neotech Ram Nasal Cannula® provided greater PLUNG, VLUNG, and PEEP than the other infant nasal cannulae during NC-IMV.

Poiseuille’s Law πr4ΔP Q = ________ 8μL Increased ID to 3mm Increased ID of delivery tubing to 3 or 3.5mm Shortened length of delivery tubing Changed shape of prongs

Thank You

NCPAP: Extubation Failures ~20-80% (8 Studies; 2001-2009) Bi-Nasal vs. Single Prongs IFD vs. V-CPAP NCPAP vs. Surf+NCPAP* IFD vs. B-CPAP Ramanathan R. J Perinatol 30:S67-S72; October 2010