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Mechanical Ventilation in COPD patients. Theodoros Vassilakopoulos Critical Care Department University of Athens Medical School Athens, Greece. Outline. Pathophysiology Non invasive ventilation during exacerbations to avoid intubation Controlled mechanical ventilation
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Mechanical Ventilation in COPD patients Theodoros Vassilakopoulos Critical Care Department University of Athens Medical School Athens, Greece
Outline • Pathophysiology • Non invasive ventilation during exacerbations to avoid intubation • Controlled mechanical ventilation • Partial support ventilation • Ventilator triggering • Wasted efforts • Weaning • Non Invasive Ventilation after weaning • Spontaneous breathing trial failure • Post extubation
Pathophysiology Barnes, P. J. N Engl J Med 2000;343:269-280
Trapped gas Tidal breathing in COPD IRV IRV VT VT Normal COPD ERV ERV
Static Hyperinflation Dynamic Hyperinflation Gas Trapping in resting conditions Hyperinflation Normal IRV IC TLC VT ERV FRC RV Gas Trapping due to exercise
600 ml 600 ml PEEPi
Flow Pes W elastic P-V curve W resistive reduction bronchial caliber W PEEPi
Decreased zoneApposition Lower rib retraction
Imbalance Load / Neuromuscular Capacity Vassilakopoulos T et al Eur Respir J 1996;9:2383-2400
Non-invasive ventilation during exacerbations to avoid intubation
Intubation rate in patients with acute exacerbation of COPD treated with and without NIPPV % of patients n=16 n=15 n=43 n=42
NIV in acute hypercapnic respiratory failure Celikel T et al, Chest 1998;114:1636-42
Hospital stay (days) of patients with acute exacerbation of COPD treated with and without NIPPV * Brochard et al. NEJM 1995;333:817
In-hospital mortality (%) in patients with acute exacerbation of COPD treated with and without NIPPV % of patients n=30 n=30 n=43 n=42
Early use of NIPPV for acute exacerbation of COPD on general wards % of patients n=118 n=118 n=118 n=118 Plant et al. Lancet 2000;355:1931
When is NIV successful? Nava et al Intensive Care Med 2006;32:361-70
Low frequency diaphragmatic fatigue takes time to recover Laghi F et al J Appl Physiol 1995; 500:193-204
End expiratory flow Slope increase Dynamic hyperinflation Flow (l/sec) Over-distension Pressure (cmH2O) Time (sec)
Assessment of mechanics V’ Ppeak Pplateau PEEPi End expiratory occlusion Rrs = (Ppeak-Pplateau)/V’
Reduce f Reduce VT Increaseinspiratory flow to prolong TE Hemodynamic compromise Overdistension with risk of barotrauma When PEEPi is present during CMV
Parthasarathy S, AJRCCM 2000;160:546-552
Pressure vs Flow triggering during ACV Aslanian P, AJRCCM 1998;157:135-43
Partitioning of pressure time product during flow and pressure triggering Assist control Pressure Support Aslanian P, AJRCCM 1998;157:135-43
Pressure vs Flow triggering with different ventilators Aslanian P, AJRCCM 1998;157:135-43
Pressure versus Flow Triggering • The effort required varies with the Ventilator • Flow triggering may require slightly less effort than pressure triggering • Any difference recorded is of minor clinical significance Tutuncu A, CCM 1997;25:756-60 Aslanian P, AJRCCM 1998;157:135-43 Goulet R, Chest 1997;111:1649-53 Giuliani R, AJRCCM 1995;151:1-9
Effect of change in PS level Yamada Y, J Appl Physiol 1999;160:1766-70
Patient effort during triggering Tobin M, AJRCCM 2001;163:1059-1063
Flow (l/sec) Paw (cmH2O) 5 sec Time (sec) Fr = 12 b/min
Flow (l/sec) Paw (cmH2O) Pes (cmH2O) 5 sec Time (sec) Fr = 33 b/min Georgopoulos D
Characteristics of preceding breaths PEEPi VT TE Leung P, AJRCCM 1997;155:1940-8