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11 th Annual Congress Turkish Thoracic Society. Mechanical Ventilation in Acute Hypoxemic Respiratory Failure. Lluis Blanch MD PhD Senior Critical Care Center Scientific Director Corporació Parc Taulí Universitat Autónoma de Barcelona Sabadell, Spain. Belek-Antalya. April 23 – 27, 2008.
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11th Annual Congress Turkish Thoracic Society Mechanical Ventilation in Acute Hypoxemic Respiratory Failure Lluis Blanch MD PhD Senior Critical Care Center Scientific Director Corporació Parc Taulí Universitat Autónoma de Barcelona Sabadell, Spain Belek-Antalya. April 23 – 27, 2008
Objectives • Safety • Efficacy • Oxygenation • Ventilation • Work of Breathing • Comfort / Synchrony • Surveillance of Flow & Pressure
Basic Principles • Maintain Comfort • Prevent Distress/ Fatigue • Workload • Mis-Matching of Flow & Timing • Avoid Iatrogenesis • Overpressure • Baro trauma & VILI • Hemodynamic compromise • Intracranial Pressure • Minimize Intubation Time • Offset Physiologic Disturbances • Reduce VO2 • Minimize Workload
Key Decisions • Intubation? • Breath Size and Timing • Flow Control: Peak 4-7 x Minute Ventilation Requirement (depends on profile & disease) • Consider APCV or Pressure Support • To Maintain End-Expiratory Volume • Gas Exchange • Prevention of Baro- Bio Trauma • Other • To Offset Auto-PEEP
Mean PaCO2≈ 60 mmHg Mean PaCO2 (FiO2 0.21 ≈ 60 mmHg) Mean PaCO2 (FiO2 > 0.21 ≈ 100 mmHg)
Targets during MV in Patients with ARDS VT 6 PEEP VT 6 VT 12 VT 12 PEEP ARDS Network N Eng J Med 2000; 342:1301-8 VT 6 Amato MBP et al. N Eng J Med 1998; 338:347-54 ARDS Network N Eng J Med 2004; 351:327-36
Targets during Mechanical Ventilation Gas Exchange ARDS Network. N Eng J Med 2000; 342:1301-8.
Increasing Respiratory Rate in ARDS Vieillard-Baron A et al. Crit Care Med 2002; 30:1407-12
Double Triggering During Assisted Mechanical Ventilation Thille AW, Brochard L Intensive Care Med 2007;33:744
Human ARDS Albaiceta GM, Blanch L, Lucangelo U. Current Opinion in Critical Care 2008;14:80-86
VT selection PEEP selection
Stroke & Acute Lung Injury RM VT PEEP
Assessment of Pulmonary Morphology in ALI Significance of Lower Inflection Point in the P-V Curve Overdistension ZEEP LIP + 2 cmH2O LIP + 7 cmH2O Vieira et al. Am J Resp Crit Care Med 1999; 159:1612-1623.
Assessment of Pulmonary Morphology in ALI Absence of Lower Inflection Point in the P-V Curve Overdistension ZEEP PEEP 10 cmH2O PEEP 15 cmH2O Vieira et al. Am J Resp Crit Care Med 1999; 159:1612-1623.
Lung Morphology & Distribution of Densities Patchy Lobar Diffuse Puybasset L et al. Intensive Care Med 2000; 26: 857-869
Patchy Lobar Diffuse Inspiratory P-V Curves in ARDS patients with Different CT Patterns Rouby et al. Intensive Care Med 2000;26:1046
P2 at PEEP 5 = 12 > PEEP 7 P2 at PEEP 12 = 28 Overdistension PEEP Selection in ARDS PEEP Albaiceta GM, Blanch L, Lucangelo U. Current Opinion in Critical Care 2008
P2 at PEEP 5 = 12 > PEEP 7 P2 at PEEP 12 = 17 Recruitment PEEP Selection in ARDS PEEP Albaiceta GM, Blanch L, Lucangelo U. Current Opinion in Critical Care 2008
The Effects of Changing VT in Patients with ARDS Roupie E et al. Am J Respir Crit Care Med 1995;152:121.
Time course of Airway Pressure During Constant-Flow Inflation Lucangelo U, Bernabè F, and Blanch L. Resp Care 2005; 50 : 55-65
ARDSNet Stress index P PEEP (cm H2O) 13,2 ± 2,4 6,8 ± 2,2 < 0,01 Table PEEPlow/FiO2 high Estrs (cm H2O/L) 34,7 ± 6,6 31,2 ± 7,4 < 0,01 EstL (cm H2O/L) 28,6 ± 6,7 26,3 ± 7,1 < 0,01 Estcw (cm H2O/L) 5,9 ± 2,4 6,2 ± 2,4 NS PaO2/FiO2 122 ± 44 110 ± 32 NS PaCO2 (mm Hg) 46 ± 6 42 ± 6 < 0,01 Open & Close b< 1 Protective b = 1 Overdistension b > 1 ARDSNet Stress Index ARDSNet: VT 6 ml/kg & Pplatt < 30 cm H2O Stress Index Strategy Plasma
Patients r=-0.85 p<0.01 Am J Respir Crit Care Med 2002; 165: 165-170
ARDS Inclusion PEEP Trial (2 h) Randomization no RM RM
Lavage Pneumonia AJRCCM 2000;161:1485-94 Responses to PEEP & VT differ among models of ALI
PaO2 Vol. Rec. [Prot.] RM Responders RM Non Responders Loss of Lung Aeration: Diffuse Loss of Lung Aeration: Focal
TEE: transgastric LV end-diastolic short axis The Impact of 10 s & 20 s Lung RM on Hemodynamics
16 pigs, saline lung lavage Histology of Liver Tissue RM + High PEEP Low PEEP RM + High PEEP was associated with more prominent inflammatory reaction in the liver sinusoids and increased levels of hyaluronan levels and other serum markers of liver injury (LDH, AST, lactate). Elevated serum levels of HA may indicate impaired uptake by damage to the endothelium of the liver sinusoids or increased release because of degradation of matrix hyaluronan in the liver.
TIPS to ventilate ALI/ARDS patients • Minimize alveolar overdistension during inspiration: • Pplat < 30 cmH2O, VT low 5 - 7 ml/kg • Minimize alveolar de-recruitment during expiration: • moderate, high PEEP • Decrease transpulmonary cycling pressure (difference between Pplat and PEEP) • Adjuncts to mechanical ventilation: RM, HFOV,….? If yes, in expert hands & in selected patients