1. Mechanical Ventilation Mary P. Martinasek BS, RRT Director of Clinical Education Hillsborough Community College

2. Goals of Mechanical Ventilation • Normalization and maintenance of blood gases • Prevention of iatrogenic complications • Support patient’s respiratory needs

3. ABG pH = 7.35 - 7.45 paCO2 = 35 - 45 mmHg paO2 = 50 - 80 mmHg Avoid high O2 sats if delivering O2

4. Common terms • PIP = Peak Inspiratory Pressure • Peep = Positive End Expiratory Pressure • Frequency = rate of ventilation (20 – 40 bpm) • I – time = Inspiratory time (.2 - .8 seconds) • MAP = Mean airway pressure • Tidal Volume = amount of air inhaled in a single breath • Minute Ventilation

5. Neonatal Ventilation • Time Cycled and Pressure Limited Ventilation • Inspiration is stopped when the selected inspiratory time has been reached • PIP is the maximum amount of pressure exerted on the patient’s airway during the inspiration • Initial values = 16-20 cmH20 of PIP • Good chest rise and Good breath sounds

7. Neonatal Ventilation • Peep = Positive pressure maintained in the patient’s airway during expiration • Prevents collapsed alveoli • Increases FRC • Improves compliance • Improves oxygenation • Decreases intrapulmonary shunting • Allows for lower PIPs to be used

8. CPAP vs PEEP • Same distending alveolar pressure • PEEP is used in conjunction with ventilator rate • CPAP is used in spontaneously breathing patient

9. Methods of administering CPAP • Endotracheal Tube • Patent airway, airway clearance • Disadvantage: plugging, malacia, infection • Nasal Prongs • Decrease infection, no malacia • Disadv. = plugging,pressure necrosis, gastric distention • Nasopharyngeal • Pressure necrosis, infection • Face Mask • Temporary measure prior to intubation or for apnea episode

10. Most popular method • High flow nasal cannula

11. ET - CPAP in Pediatrics • Pre and Post operatively to support structures • Subglottic stenosis • Cleft palate • Laryngeal papillomas • Neck tumors • Tonsillitis • epiglottitis

12. Indications for NCPAPAARC Clinical Guidelines • Increased WOB with retractions, flaring, grunting and cyanosis • Inadequate ABG’s • Presence of poor expansion on CXR • Presence of conditions responsive to CPAP • RDS, Pulmonary edema, atelectasis, apnea, tracheal malacia, TTN

14. Contraindications to NCPAPGuidelines • Upper airway abnormalities • TEF, choanal atresia • Severe cardiovascular instability and impending arrest • Unstable respiratory drive • Ventilatory failure

15. Hazards of NCPAP • Air leaks • Ventilation Perfusion Mismatch • CO2 retention and increased WOB • Increase in PVR due to impedence of blood flow • Nasal irritation with septal distortion • Pressure necrosis • Nasal mucosal damage due to inadequate humidification

16. MAP • Most powerful influence on oxygenation • Average pressure exerted on the airway and lungs for the entire breath cycle • Affected by: PIP,PEEP,I-Time, Rate • High levels can lead to decreased CO, pulmonary hypoperfusion and barotrauma

18. Physiologic Deadspace • Physiologic = anatomic + alveolar • Anatomic = Gas that fills the airways and never participates in gas exchange • Alveolar = gas that goes to unperfused alveoli and thus never participates in gas exchange • Nl physiologic Vd in neonate = 2cc/kg

19. Flow rate • Flow rate used determines the type of wave pattern • Goal is to set flow to allow maximum diffusion time without causing turbulent flow • Diffusion time is the length of time that the gas is in contact with the alveoli

22. Indications for Vent Support • Respiratory Failure • Hypoxemic respiratory failure • PaO2 less than 50 on FIO2 greater than 60 • Hypercapnic respiratory failure • PaCO2 greater than 50 and pH less than 7.25 • Mixed respiratory failure • Both hypoxemia and hypercapnia

23. Initial Setting on neonatal vent • Time cycled – Pressure Limited ventilator • PIP set 15 – 20 cm H20 • Peep set 3 – 5 cm H2O • Rate set 20 – 40 bpm • Flow set 6 – 8 lpm • I time set .3 - .5 seconds for LBW and .5 - .8 seconds for larger infants

24. Settings • PIP – good chest excursion, good lung aeration • Vt in pressure control = PIP – PEEP • Vt in pressure control changes with change in compliance and resistance • PIP set – change only with changes in compliance and resistance in 2 cm increments