Noninvasive Oxygenation and Ventilation

Goals of noninvasive measures Either short term or long term support of pulmonary function Short Term Hospital NC BiPAP for acute respiratory distress Long Term Home O2 for chronic COPDers CPAP for Obesity Hypoventilation Syndrome or OSA

What goal for oxygen? COPDers Non-COPDers Between 88 and 95% PaO2 >= 60 Non-COPDers >= 92% PaO2 > 60

O2 Saturation vs. PaO2 40-50-60 to 70-80-90 rule PaO2 O2 Sat 40 70 50

Types of NIV Nasal Cannula Venti-Mask Non-rebreathers BiLevel CPAP

Non-Invasive Oxygenation: Achieved FiO2

Venti-Mask colors

Non-Rebreather versus Partial Non-rebreather

Non-Invasive Ventilation BiLevel CPAP (not discussed)

Advantages to Noninvasive Ventilation No internal traumatic complications Decreased infections Less interference with communication and swallowing Less need for sedation

Indications Well established Weaker indications COPD exacerbation Weaning in COPD patients Acute cardiogenic pulmonary edema Immunocompromised patients DNI patients Weaker indications Asthma exacerbations Cystic fibrosis Hypoxemic respiratory failure Extubation failure

NIV and COPD RCTs have shown 20-50% reduced intubation rate Improved RR, dyspnea and gas exchange Decreased length of stay Lowered mortality Intubated COPD patients who have failed T “piece” trials Should be able to breath without assistance for 5 minutes Can tolerate levels of pressure generated by NIV Should not be “difficult” intubations

NIV and Asthma Physiological Rationale Limited evidence Decrease work of breathing Improve exchange Limited evidence No consistent recommendations for trial of NIV in patients failing standard therapy

Acute Cardiogenic Pulmonary Edema Physiology Recruits “flooded” alveoli Reduces preload and afterload RCTs have shown that BiPAP/CPAP can Improve dyspnea and oxygenation Lowers intubation rate Reduced intubation Reduced LOS Reduced mortality

Immunocompromised Patients Mechanical ventilation in these patients have a high risk of Nosocomial infection (VAP) and septicemia Fatal airway hemorrhage caused by thrombocytopenia and platelet dysfunction NIV begun in these patients before respiratory failure becomes severe may halve mortality Greatest benefit with early initiation and single-organ failure

Post-op Patients CPAP reduces intubation in patients after abdominal surgery (reduces atelectasis) NIV improves outcomes in hypoxemic respiratory failure after lung resection

Predictors of NIV success in acute respiratory distress Cooperative patient Intact neurological function Good synchrony with ventilator APACHE score <29 pH > 7.25 Intact dentition Air leaking well-controlled Able to control secretions

Selection guidelines for use of NIV in acute respiratory distress Appropriate diagnosis with potential reversibility over hours to days Ascertain need for ventilatory assistance Moderate to severe respiratory distress Tachypnea (>24/min for COPD, >30/min for hypoxemia Accessory muscle use or abdominal paradox Blood gas abnormality pH < 7.35, PaCO2 > 45 or PaO2/FiO2 < 200

Contraindications for NIV Respiratory arrest/Cardiac arrest Medically unstable (hemodynamically unstable, arrythmias, cardiogenic shock/MI, GIB, ABG pH < 7.1) Unable to protect airway (bulbar dysfunction, AMS) Excessive secretions Uncooperative or agitated Unable to fit mask (facial trauma/surgery) Recent upper airway or GI surgery

BiLevel – What is it? IPAP (Inspiratory Positive Airway Pressure) Excess pressure to move air into lungs EPAP(Expiratory Positive Airway Pressure) Increased minimum lung pressure maintained to increase alveolar recruitment PS (Pressure Support) PS = IPAP - EPAP

BiLevel – Setting? IPAP Usually 8-12 cm H2O EPAP Usually 4-5 cm H2O

BiLevel - Recheck A baseline ABG should be done during initial episode of respiratory distress Patient should be followed-up in 1-2 hours depending on condition after BiLevel NIV is placed

BiLevel – Recheck Criteria Objective Compare repeat ABG to baseline PaO2/FiO2 should be > 150 after 1st hour Gas Exchange: Oximetry, PaCO2, pH RR, HR, BP, cough strength and ability to raise secretions should be improved Subjective Comfort/Discomfort Feeling of dyspnea Ventilatory Function Synchrony Tidal Volume Airleaks Wave form

BiLevel - Complications