The role of NIV in ARDS 호흡기 내과 R3 박지영

ARDS  Clinical syndrome of severe dyspnea of rapid onset, hypoxemia, and diffuse pulmonary infiltrates leading to respiratory failure  Diagnostic Criteria for ALI and ARDS OxygenationOnsetCXRAbsence of LA HTN ALI : Pa O2 /FI O2 ≤300mmHg ARDS : Pa O2 /FI O2 ≤200mmHg acutebilateral alveolar or interstitial infiltrates PCWP≤18mmHg or no clinical evidence of increased LAP

ARDS Direct Lung injuryIndirect Lung injury PneumoniaSepsis Aspiration of gastric contentSevere trauma Pulmonary contusionMultiple bone fractures Near-drowningFlail chest Toxic inhalation injuryHead trauma Burns Multiple transfusions Drug overdose Pancreatitis Post-cardiopulmonary bypass  Clinical Disorders Commonly Associated with ARDS

Lung injury after thoracic surgery  Incidence of ARDS or ALI 4–7% for pneumonectomy, 1–7% for lobectomy  Potential causes of pulmonary edema following pneumonectomy Fluid overload Lymphatic damage Pulmonary capillary pressure changes Pulmonary endothelial damage Volume induced lung injury (volutrauma – OLV) Right ventricular dysfunction Oxygen toxicity Gothard J. Curr Opin Anaesthesiol. 2006;19(1):5-10

Lung injury after OLV  Risk factors for acute lung injury after thoracic surgery for lung cancer Duration of surgery and OLV Intraoperative ventilatory hyper-pressure Licker et al. Anesth Analg 2003; 97:1558–1565  High inspired-oxygen concentrations  Administration to Contralateral lung during thoracotomy  Release of reactive oxygen species in the form of oxygen free radicals  At toxic levels, cause molecular and ultimately cellular damage Gothard J. Curr Opin Anaesthesiol. 2006;19(1):5-10

ARDS TreatmentRecommendation Mechanical ventilation: Low tidal volumeA High-PEEP or "open-lung"C Prone positionC Recruitment maneuversC High-frequency ventilation and ECMOD Minimize left atrial filling pressuresB GlucocorticoidsC Surfactant replacement, inhaled nitric oxide, other antiinflammatory therapy (e.g. ketoconazole, PGE 1, NSAIDs) D

ARDS  Mortality : 41 ~ 65%  Largely attributable to nonpulmonary causes (sepsis and nonpulmonary organ failure)  >80% of deaths  Risk factor Advanced age ->75 years (~60%) --- <45 years (~20%) Preexisting organ dysfunction from chronic medical illness (chronic liver disease, cirrhosis, chronic alcohol abuse, chronic immunosuppr ession, sepsis, chronic renal disease, any nonpulmonary organ failure) Increased APACHE II scores Patients with ARDS from direct lung injury > indirect lung injury X 2

NIV  Non-invasive ventilation (NIV) Support through a tight-fitting face mask or nasal mask Traditionally used for treatment of sleep apnea Recently used as primary ventilator support for impending resp. failure PSV or bi-level positive airway pressure ventilation Well tolerated by the conscious patient Optimized patient-ventilator synchrony Major limitation : patient intolerance  Tight-fitting mask required for NIV : physical and emotional discomfort

 Different types of interfaces A.Full face (or oronasal) mask B.Total face mask C.Nasal mask D.Mouthpieces E.Nasal pillows or plugs F.Helmet

The advantages of NIV  … than endotracheal intubation Lower risk of nosocomial infections Less antibiotic use Shorter lengths of stay in the intensive care units More comfortable Need for sedation and analgesia↓ (independent factor for extended weaning)

Antonelli et al. Eur Respir J 2003; 22: Suppl. 42, 65s–71s

Nicholas S. Hill et al. Crit Care Med 2007 Vol. 35  Noninvasive ventilation for various types of acute respiratory failure (ARF): Evidence for efficacy and strength of recommendation

IndicationContraindication Moderate to severe dyspneaRespiratory arrest Tachypnea (RR>24/min for COPD, >30/min for CHF) Medically unstable Accessory muscle useUnable to protect airway Abdominal paradoxExcessive secretions PaCO2 >45 mm Hg, pH <7.35Agitated, uncooperative PaO2/FIO2 <200Recent UGI or airway surgery Unable to fit mask  General guidelines for selection of patients for noninvasive ventilation Erik Garpestad et al. Chest 2007;132;

Erik Garpestad et al. Chest 2007;132;

Graeme M. et al. Chest 1999;115; case: Pa O2 /FI O2 25% ↑

Ritesh Agarwal et al. Respiratory Medicine (2006) 100 intubation rates mortality rates

The most important thing is..  The role of NIV in ARDS..? Controversial !  NIV failure  higher mortality Monitoring patients closely on NIV Switching promptly to intubation when necessary