Care of the Preterm Infant: Non-invasive Ventilation and Other Related Important Stuff SE Courtney, MD MS Professor of Pediatrics Stony Brook University Medical Center Opening the Lung Congratulations! Baby is at OPTIMAL MEAN AIRWAY PRESSURE Optimal Mean Airway Pressure Benefit Overdistension Atelectasis Pressure CPAP/PEEP: DR and beyond • CPAP/PEEP should be used from the beginning • If a self-inflating bag must be used, equip it with a PEEP valve • Consider T-piece resuscitator Finer NN et al, Resuscitation 2001 Use of oxygen Oxygen Toxicity • • • • Retinopathy of prematurity Increased days on ventilator Increased days on oxygen Increased incidence/severity of BPD Finer N and Leone T. Oxygen saturation monitoring for the preterm infant: The evidence basis for current practice. Pediatr Res 2009;65:375-380 Oxygen in the Delivery Room • A blender and pulse oximeter should be used • Start with 30 or 40% oxygen in the preterm infant • Saturations of around 80% at 5 minutes are normal Oxygen in the NICU • Saturations of 85-93% appear to be safe Temperature control Admission temperature <36 degrees centigrade is an independent risk factor for mortality in the preterm infant. CPAP and Non-invasive Ventilation Goal of Mechanical Ventilation To get the patient OFF mechanical ventilation! • Airway trauma • Infection • Decreased mucus clearance • Over-ventilation • Air leak • Contribution to BPD NCPAP is probably a good thing • CPAP Reduces mortality and respiratory failure in RDS • Early CPAP reduces need for mechanical ventilation • CPAP post-extubation can prevent extubation failure • NO STUDY has shown reduction in BPD with use of CPAP under any conditions (testimonials don’t count) NCPAP/NIV • Constant-flow – conventional – bubble • Variable-flow – Infant Flow – Bi-level • NIPPV Not all CPAP is created equal: Know your equipment • Variable-flow NCPAP recruits lung volume well and decreases work of breathing. Care must be taken to avoid nasal trauma. • Bubble NCPAP: pressures must be monitored; they will be higher than the depth of the underwater expiratory tube. CPAP by Conventional Ventilator • Constant flow of air/oxygen. • CPAP provided by changing orifice size at expiratory port of the ventilator, thus providing back-pressure. • Variety of prongs, usually bi-nasal. • Convenient, easily available, inexpensive. “Bubble” NCPAP 12 Ventilator: open symbols Bubble: solid symbols 10 8 8 6 4 4 No Leak 2 4 6 8 10 Bias Flow (Liters/min) Kahn DJ et al, Pediatric Research 2007;62:343. 12 (set NCPAP) Mean (+/- SD) Pressure (cmH 2O) “Bubble” NCPAP – Do We Know What We’re Doing? Kahn et al, Pediatrics, 2007 70 150 B-NCPAP V-NCPAP Heart Rate (min-1) 65 TcO2 (mmHg) B-NCPAP Pp=0.01 V-NCPAP 60 55 50 145 140 135 3 5 7 4 2 3 Set NCPAP (cmH2O) 5 7 4 2 Set NCPAP (cmH2O) 97 56 B-NCPAP 96 V-NCPAP SaO2 (%) TcCO2 (mmHg) 54 52 50 95 94 93 48 B-NCPAP 92 V-NCPAP 46 91 3 5 7 4 Set NCPAP (cmH2O) 2 3 5 7 4 2 Set NCPAP (cmH2O) Courtney et al, Bubble vs ventilator NCPAP, J Perinatol 2010 Variable-Flow (Infant Flow) CPAP • Flow is varied to deliver the required CPAP pressure. • The direction of flow depends on the pressures generated by the patient. • On inspiration, the CPAP flow is towards the nasal cavity, assisting in inspiration • On exhalation, the flow is down the expiratory branch of the CPAP tubing. Childs, Neonatal Intensive Care, 2000 What Do We Know About Variable-Flow NCPAP? • Provides a very stable mean airway pressure • Decreases work of breathing • Increases lung volume recruitment Adapted from Moa G and Nilsson K. Acta Paediatr 1993;82:210. C = Cannula A = Aladdin (Infant Flow) I = Inca Prongs (Conventional Ventilator) Courtney SE, Pyon KH, Saslow JG et al. Pediatrics 2001;107:304-308 Pandit PB, Courtney SE, Pyon KH et al. Pediatrics 2001;108: 682-685 100 Failure (%) 80 60 40 38.1 38.5 Conventional Infant Flow 20 0 Stefanescu et al, Pediatrics 2003;112:1031 Secondary Outcomes Conv IF P Days on O2 77.2 65.7 0.03 Length of Stay 86.3 73.7 0.02 Stefanescu et al, Pediatrics 2003;112:1031 16% Apnea Hypoxia Apnea / bradycardia 58% FiO2>0.5, CPAP>8 cm PaCO2>65, pH<7.25 Hypercarbia Surgery 15% 3% 8% Stefanescu et al, Pediatrics 2003;112:1031 Other NCPAP with a Rate: (NIMV, NIPPV) NIMV for reducing apnea and extubation failure • Synchronized (?)NIMV reduces the incidence of extubation failure and possibly apnea more effectively than NCPAP. • “Synchrony” done with Graesby capsule and Infant Star ventilator • No information is available on non-synchronized NIMV. • Current studies ongoing Owen LS, Morley CJ, Davis PG. PAS 2009 SiPAP What is SiPAP? – A small (2-3 cmH2O), slow, intermittent increase in CPAP pressure for a duration up to 3 seconds to produce a “Sigh” – Enables the infant to spontaneously breathe throughout the cycle Small increases in IF CPAP pressure can change lung volume by 4-6 ml/kg. 14 Volume Change (ml/kg) Unlike NIPPV, SiPAP pressure rise is only 2-3 cmH2O 12 10 8 6 5.5 ml/kg 4 2 0 0 2 4 6 8 10 CPAP Pressure Adapted from Pandit PB, Courtney SE, Pyon KH et al. Pediatrics 2001;108: 682-685 SiPAP can therefore potentially: • Recruit lung volume • Decrease work of breathing • Stimulate the respiratory center Patients who may benefit from SiPAP: • Infants weaning from mechanical ventilation • Premature infants that don’t require aggressive support • Infants with apnea Nasal Bilevel vs Continuous Positive Airway Pressure in Preterm Infants. Migliori C et al, Pediatr Pulmonol 2005;40:426. Nasal CPAP vs Bi-level nasal CPAP in preterm infants with RDS: a randomized control study. Lista G et al, Arch Dis Child Fetal Neonatal Ed. 2009 40 infants enrolled, mean GA 30wks, BW 1400g. IF-CPAP SiPAP P Respiratory support (d) 6.2 ± 2 3.8 ± 10 0.025 O2 dependency (d) 13.8±8 6.5 ± 4 0.027 GA at discharge (wk) 36.7± 2.5 35.6±1.2 0.02 SiPAP vs NCPAP Work of Breathing and Respiratory Parameters S. Courtney, M. Weisner, V. Boyar, R. Habib • 17 infants <1200gms birth weight, on NCPAP for mild respiratory distress • Each infant own control; order of application randomized and data collected in two periods for a minimum of one hour, with 15 min on each device in each period (ie, CPAP/SiPAP, CPAP/SiPAP • Data collected using calibrated respiratory inductance plethysmography; esophageal balloon for estimation of pleural pressure • Continuous monitoring of saturation, pulse, transcutaneous oxygen and carbon dioxide Minute Ventilation 320 Minute Ventilation 280 260 240 220 MV (ml/kg/min) 300 n=13 P=0.037 CPAP SiPAP Period I CPAP SiPAP Period II Synchronized Non-invasive ventilation Shortcut to Graph.PNG.lnk Conclusions about SiPAP • Appears to be at least as effective as NCPAP • May improve gas exchange and decrease minute ventilation (?decrease WOB) • Synchrony may be useful NCPAP by Nasal Cannula NCPAP by Cannula • Uncontrolled positive pressure may be generated with nasal cannula • Amount of positive pressure generated will depend on cannula size, flow rate, and shape of nasal passages. • High humidity, high flow cannulas also may pose an infection risk. Nasal Cannula Use Current literature would support that gas delivered by nasal cannula: • be heated and humidified • not exceed 1 L/min in infants <1500gm • not exceed 2 L/min in infants >1500gm If CPAP is desired, a CPAP device should be used. Non-invasive Ventilation is not appropriate when… • Infant cannot maintain oxygenation (FiO2 > 0.5-0.6) • PCO2 >60 • pH < 7.25 • Increased work of breathing • Apnea Questions……………. • Over the long term, is any one form of NCPAP more advantageous than any other? • Is non-invasive ventilation combined with NCPAP advantageous? Is S-NIPPV better? • When should NCPAP be initiated? • When and how should surfactant be given for babies on NCPAP only? • What levels of pH and PCO2 are “safe” for babies on NCPAP? Keep an open mind and something useful may fall into it.