2IntroductionWith increased survival of very low birth weight (VLBW) infants, the number of infants who require prolonged mechanical ventilation (MV) has increasedThe pulmonary management of these infants is directed at minimizing the need for prolonged MV to reduce ventilator-induced trauma and oxygen toxicityEarly extubation often presents difficulties because of upper-airway instability, poor respiratory drive, alveolar atelectasis, and residual lung damageKhalaf et al Pediatrics 2001; 108:13-17
3BackgroundUse of Nasal respiratory support (NARES) is on the rise to decrease post-extubation failures, bronchopulmonary dysplasia (BPD), and for the treatment of apnea of prematurityCPAP, by various means, commonly is used to wean premature infants from mechanical ventilation
4NCPAP Failure RatesNCPAP use is associated with failure rates of 20 to 80% in preterm infantsReasons for failure include recurrent apnea/ bradycardia/desaturations or respiratory acidosis requiring intubation or re-intubationRamanathan et al J Perinatol October 2010; 30:S67-S72
5BackgroundThe 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 airwayFriedlich et al J Perinatol 1999; 19:Barrington et al Pediatrics 2001; 107:
6NCPAP vs. NIPPV for NARES Additionally, NIPPV has been shown to decrease NCPAP failure rates to 5 -20%
7Background Typical nasal interfaces used: Short bi-nasal prongs Inca prongs or Argyle ProngsNasopharyngeal prongsNasal mask with SiPAP machineVariable flow devicesInfant Flow Drivers with nasal prongs or nasal mask.Problems with these nasal interfacesCumbersomeMucosal irritation, bleeding, nasal traumaObstruction due to secretions in the nose or nasopharynx
8BackgroundHigh flow nasal cannula systems are increasingly adopted because of the ease of useVapotherm, Fisher Paykel HFNCHowever, these HFNC systems have no ability to measure or limit the pressure delivered to the babyThere are no pop-off valves in these systemsOnly pop-off is at 20 PSI to protect the device and not to protect the babyCan generate significant amount of distending pressures at the nasal interfaceAir leaks have been reported
9IndicationsTo facilitate extubation of mechanically ventilated neonatesAs a primary mode of support for neonates with respiratory distressInfants with moderate-to-severe apnea
10MaterialsWe 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
11Materials Nasal cannula-short tubing Connected to larger adapter Larger circuitSame humidity, but heating at 40°C
13NC-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 cannula7 LPM if using Infant size Nasal cannulaIMV rate: started at a maximum of 40 bpmPIP: Same as the most recent Conventional Ventilator PIP (max 30 CmsH2O)PEEP: 5 cmsH2OInsp. Time: 0.5 seconds
15Weaning Protocol Wean PIP first Once PIP was around 10, rate was decreased to 10If infant remained stable, switched to NC-CPAPIf infant was stable for hours on NC-CPAP, switched to low flow nasal cannula (<2 LPM)
16Results: (n=183) 15 (8 %) Range 385 – 4167 23 – 41 109 (60 %) 1 -124 Birth weight (g)385 – 4167Gestational Age (weeks)23 – 41BW < 1500 g (n) (%)109 (60 %)NC-IMV start (days)1 -124Duration of NC-IMV (days)1 - 49NC-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-IMVRamanathan R, Andaya S et al, SPR Meetings, Vancouver, May 2010
17Previous Studies All infants tolerated NC-IMV All infants tolerated feeds during NC-IMVNo cases of nasal injury, or gastric perforation were seenNC-IMV failure rate requiring intubation in our study population was 8%
18Conclusion NC-IMV is feasible and well tolerated. TCPFL NC-IMV allows clinicians to limit pressures and can be delivered safely to neonatesTherefore, 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 prematurityWhile reducing obstacles such as mucosal irritation, bleeding, nasal trauma, or obstruction due to secretions in the nose or nasopharynx.
19A 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
20NC-IMVNasal 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
21HypothesisNC-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
22ObjectiveTo determine the magnitude of pressure and volume delivered to an infant nasal airway/lung modelUsing different sized nasal cannulaAt different peak inspiratory pressure (PIP) settings during constant flow, time-cycled, pressure-limited ventilation.
23MethodsWe 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.
24Methods28 week premature infant airway model that was reconstructed from a head CT scan and a rapid prototyping device