9/15/2017. Disclosures. Heated High Flow Nasal Cannula: Hot Air or Optimal Noninvasive Support? Objectives. Aerogen Pharma

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1 Heated High Flow Nasal Cannula: Hot Air or Optimal Noninvasive Support? Rob DiBlasi RRT-NPS, FAARC Program Manager Research/QI, Respiratory Therapy Principle Investigator, Seattle Children s Research Institute March 22, 2017 Disclosures This lecture is supported with a grant from Vapotherm Have received research funding and speaker honoraria from: Draeger Medical Mallinckrodt Medical Aerogen Pharma Objectives Heated and Humidified High Flow Nasal Cannula (HFNC) Learning objectives for this presentation: Review theoretic functional differences between Nasal CPAP and high flow nasal cannula (HFNC) Explore physiologic data comparing HFNC to other noninvasive strategies Review data from a recent bench study that helps to provide corroborative data Identify specific patient populations that are difficult to wean from HFNC Attempt to define age-specific HFNC therapeutic levels and review policy and procedures CO2 CO2 HFNC provides a monophasic oxygen flow heated and humidified (100% BTPS) Open System resulting in leaks Improves oxygenation: PaO2 (FiO2), humidity, PEEP Improves ventilation PaCO 2, V T, RR and VE CO 2 rebreathing from anatomic deadspace Indicated therapeutic flow setting currently unknown Disruptive Technologies A disruptive innovation is an innovation that creates a new market and value network and eventually disrupts an existing market, displacing established market leaders, products and opinions Disruptive medical innovations tend to be produced by clinicians and researchers, rather than existing marketleading companies 1

2 HFNC Interfaces may be more comfortable than N-CPAP Airway Injury with Nasal CPAP CPAP use may: Increase the risk for tissue necrosis, nasal stenosis, deformity, and PnTx Increased need for sedation Interface may impact bonding, suck feeding, and positioning Reported advantages of HFNC over CPAP: Reduced rates of nasal trauma Reduced infant pain scores and stress Preferred by parents and nursing staff Less PnTx Photos Courtesy of Rose DeClerk, Vermont Oxford and Louise Owen Perceived limitations of HFNC Physic of Gas Flow: NCPAP Pressure is highly variable and cannot be measured or regulated There are no alarms with most HFNC systems Distending airway pressure generated by HFNC may lead to lung injury (overexpansion or atelectasis) and contribute to the development of BPD in infants Inability to select properly sized prongs could increase risk for VILI and gastric insufflation DiBlasi,. Resp. Care Journal, 2016 High Flow Nasal Cannula Flow Rate> 2 L/min; monophasic flow CO2 CO2 Everybody Seems to Be Going With the Flow. Photo courtesy of Tom Miller PhD 2

3 % of All Pt Days with HFNC in Use Feb-12 Apr-12 Jun-12 Aug-12 Oct-12 Dec-12 Feb-13 Apr-13 Jun-13 Aug-13 Oct-13 Dec-13 Feb-14 Apr-14 Jun-14 Aug-14 Oct-14 Dec-14 Feb-15 9/15/2017 Apr-15 It is Being Used to Treat a Number of Maladies Is it possible that it is being applied when it is not always necessarily indicated? No one Knows What the Flow Should Be Set At 12 THE QUESTION: Overutilization of HFNC? What level of support is provided with HFNC? Are there physiologic benefits with HFNC? A management protocol in the US is nonexistent (Infant through Adult) Translational Research Questions Does HFNC provide pressure similar to CPAP? Does HFNC reduced exhaled CO 2 re-breathing from the anatomic deadspace? Are there differences in the level of CO 2 washout related to different patient sizes? What happens to pressures and CO 2 with mouth open/closed? Can these effects be studied in a bench model or humans? Can HFNC use affect outcomes in our patient population that are different from other noninvasive forms of support? Defining the HFNC System 3

4 Lung Models Premature Term Neonate Neonate (4.0 kg) (1 kg) Toddler (10 kg) Small Child (20 kg) Adult (70 kg) Compliance (ml/cmh 2O) Resistance (cmh 2O/L*s -1 ) Spontaneous Muscle Pressures (cmh 2O)* Tidal Volumes (ml) 6 ml/kg Rate (I:E 1:3)** Minute Ventilation (L/min) Deadspace Volume (ml) (Deadspace/Tidal Volume) 9 (150%) 13 (54%) 33 (55%) 42 (35%) 110 (26%) DiBlasi et al., PAS, 2016 Cannula Devices and Settings End-Expiratory Pressures Fisher and Paykel Nasal Cannula Model and prong sizing Vapotherm (ID,OD mm) OPT 312 (1.0, 2.5) MN1100A (1.2, 2.4) OPT 314 OPT 316 (1.6,2.8) (2.1,3.6) MI 1300 (1.7, MPS ) (1.7, 3.2) OPT 942 (3.5, 4.5) MP 1500 (2.5, 4.7) OPT 944 (4.1, 4.8) MA 1700 (3.0, 5.2) Fisher and Paykel Nasal Occlusion (Cannula prong OD/Nasal Vapotherm airway ID) 63% 53% 51% 59% 45% 60% 58% 46% 57% 43% High Flow Nasal Cannula Flow Settings Range (L/min) Protocol Development End expiratory pressure with HFNC Age Group Definition of HFNC* Acute Care Minimum HFNC Flow Rate (bronchiolitis pathway) Acute Care Maximum HFNC Flow Rate ICU Maximum HFNC Flow Rates Flow Rate (L/min) HFNC Estimated PEEP minimum (cm H2O) (L/min) Estimated PEEP (cm H20) HFNC maximum (L/min) Estimated PEEP (cm H2O) HFNC maximum Estimated PEEP (cm (L/min) H2O) 0-90d d-6mo 4 <1 4 < >6mo-1yr 5 <1 5 < >1 yr-2yr 6 <2 5 < >2yr-8yr 6 <1 6 < >8yrs 8 <1 8 < PEEP values are estimated at each HFNC settings using a spontaneously breathing lung model and 3D anatomic airway with Vapotherm device. *HFNC definition based on estimated inspiratory flow for average weight in term infant through adolescent patients; patients who are not on the bronchiolitis pathway and are receiving flow below that defined as HFNC for age may be candidates for weaning / discontinuation and should be discussed with medical team; patients requiring oxygen after HFNC should be supported with a NC attached to an oxygen flow meter (without blender) before acute care transfer. "Where there is no standard, there can be no improvement" -Taiichi Ohno Iyer et al., Respiratory Care Journal,

5 Physics Miller et al., J Pulm Respir Med, End expiratory pressure with HFNC in Adults Flow Effects: End-Tidal CO 2 (alveolar ventilation) 2L:26.3±2.7 2L: 35.4±1.7 2L: 5.3±1.3 2 L: 10.4±1.6 4 L: 7.2±0.9 4 L: 19.1±0.7 6 L: 7.6±2.1 Park RL et al., Respir. Care, 2015 Flow Effects Insp. CO 2 (deadspace) Pre-term: Vapotherm 8 L/min Term: Vapotherm 8 L/min Adult: Vapotherm 40 L/min 5

6 Can High Flow Wash-Out Deadspace During Inhalation? Peak exhalation Peak inhalation Moller et.al.,j Appl Physiol, 2017 HFNC 60 L/minIP: 1.64 cmh 2 O; EP:4 cmh 2 O Kumar et al. Resp Phys Neuro, 2015 Is flushing effect limited to exhalation? Is flushing effect limited to exhalation? Change Point ~20 L/min Change Point ~2.4 L/min Dead Space Flush: (9 ml/1.12s)*60=0.48 L/min =minimum flow needed to purge deadspace through leak during exhalation Inspiratory Flush = (15 ml/0.38s)*60= 2.4 L/min =leakage flow where airways and lung are purged of CO 2 during inhalation Dead Space Flush: (110 ml/3.35s)*60=1.97 L/min =minimum flow needed to purge deadspace through leak during exhalation Inspiratory Flush = ( ml/1.65s)*60= L/min =leakage flow where airways and lung are purged of CO 2 during inhalation Is CO 2 response between HFNC, NCPAP, and NIV Different? CO2 flush in Adult 44% 15% 35% 28% Mukerji et al. J Perinatol Fricke et al. Resp Med Case Reports,

7 Data Summary HFNC provides similar distending pressure as N-CPAP HFNC may purges anatomic deadspace and reduces rebreathing of inspired/exhaled CO 2 Differences in anatomic airway size, proportion of deadspace to tidal volume, breathing pattern, and lung mechanics Clinical Questions Can HFNC be used safely and effectively as an alternative to N-CPAP in term and pre-term infants as an initial form of support or following extubation? Short-term pulmonary physiologic outcomes (WOB, gas exchange, AOP, and lung recruitment) Morbidity/mortality (Death, BPD, other complications) Nasal airway injury Pneumothorax Short-term physiologic outcomes: WOB Clinical Data Neuth et al., Peds Pulm 46:67-74 (2011) Short-term Physiologic Studies: recruitment HFNC in Premature Infants Following Extubation Following extubation (6 studies,n=934), no differences between HFNC and CPAP: death or CLD rate of treatment failure or reintubation Infants randomized to HFNC had lower nasal trauma and pneumothorax Subgroup analysis found no difference in the rate of the primary outcomes between HFNC and CPAP in preterm infants in different gestational age subgroups, small number infants <1200 grams For infants weaning from non-invasive respiratory support (CPAP), two studies (n=149) found that preterm infants randomized to HFNC had a reduced duration of hospitalization compared with infants who remained on CPAP 7

8 Total Days of Therapy/Total Patient Days 9/15/2017 The HIPSTER Trial Outcomes Study stopped after two years; HFNC=278 and CPAP=286 RCT - HFNC noninferior to CPAP as primary respiratory support for preterm infants (gestational age, 28 weeks 0 days) with early RDS HFNC group received an initial gas flow of 6 to 8 L/min from either the Optiflow Junior (F&P Healthcare) or Precision Flow (Vapotherm) device with crossover to N-CPAP (94% vs 6%) Nasal CPAP group received 6-8 cmh 2 O using three different kinds of N-CPAP Treatment failure (FiO2 >0.40) within 72 hours after randomization was greater (25.5%) in the HFNC than N-CPAP group (13.3 vs 25.5%; P<0.001) Length of support and oxygen requirement greater in HFNC group No difference in intubation rates at 72 hours (15.5 vs 11.5), BPD, mortality, IVH, NEC, PVL, surfactant, etc. Urgent need for intubation occurred more frequently in the CPAP group than HFNC group (18.4% vs. 5.6%, P = 0.03) Nasal trauma (8.3 vs 18.5%; P<0.001) and pneumothorax and airleak lower (0 vs 6%; P<0.02) during HFNC than N-CPAP Roberts et al., NEJM, 2016 Roberts et al., NEJM, 2016 Clinical Outcomes: Comparing HFNC to NIV 1.2 HFNC Use at SCH: A Snap Shot from the NICU NO documented airway Injury or pneumothorax HFNC does not provide inspiratory pressure but CO 2 purging during inhalation and exhalation may provide a similar ventilation effect as NIV HHHFNC maybe as effective as NIPPV in preventing endotracheal ventilation in the primary treatment of RDS in premature infants Neonates Kugleman, Peds Pulm, 2016; Lavazarri 2016, JamaPediatrics Adults Ni YN, Chest. 2017, Nagata K, Respiratory Care % 58% 36% % change based on mean values NCPAP-NIMV PER PT DAY HHFNC PER PT DAY INVASIVE VENTS PER PT DAY HFNC Use In BPD Special Pediatric Populations Practices are disparate nationally and some do not use HFNC because they are not able to go home with it Weaning at SCH is clinically-based: Tracheomalacia or other airway anomalies (obstruction) Gas Exchange: serum CO 2 and HCO3 - RR and WOB Judicious reductions in flow (~0.5 to 1 L/min/wk) Weaning HFNC coincides with steroid wean 8

9 HFNC Use In BPD Physiologic Effects of HFNC in BPD Former 28 week preemie with severe BPD admitted for viral bronchiolitis Receiving 7 L/min HFNC Enrolled in HFNC study No Airway Anomalies or TBM DiBlasi et al.,unpublished Data Cardiac Patients: A sensitive Patient Population Initiated Sprinting Trials 2L to 0.5 L Placed back on 0.5 L NC Off high flow Removed from 0.5 L NC HFNC Use In Bronchiolitis HFNC Utilization in Patients with Bronchiolitis Cochrane Meta-analysis (2014): There is insufficient evidence to determine the effectiveness of HFNC therapy for treating infants with bronchiolitis Absence of evidence may not be evidence of absence Short-term physiologic studies have shown improved gas exchange and reduced WOB 9

10 PERCENT OF PT DAYS ON HFNC Jan-13 Feb-13 Mar-13 Apr-13 May-13 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr-14 May-14 Jun-14 Jul-14 Aug-14 Sep-14 Oct-14 Nov-14 Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15 Nov-15 Dec-15 Jan-16 Feb-16 Mar-16 Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 9/15/2017 PERCENT OF PT DAYS ON HFNC Is it all hot air? 14% 13% 12% 11% 10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% 10