Lluís Blanch M.D., Ph.D.Consultant Critical Care

Scientific Director Corporació Parc TaulíUniversitat Autónoma de Barcelona

Sabadell, Spain.

Cairo 3 - 4 February 2010

Lung Mechanics Beyond Basics

10th Pulmonary Medicine Update Course

kC

VRVPaos Pr

Equation of motion

PeepiPelesPaos PrPr

Time

VCV. Effects of an End-Inspiratory Occlusion

Effect of Increasing Elastance during CF.VCVChange in the Slope of Pao(t) Curve

Lucangelo U, Bernabè F, and Blanch L. Resp Care 2005; 50 : 55-65

Time course of Airway Pressure During Constant-Flow Inflation

Albaiceta GM, Blanch L, Lucangelo U. Current Opinion in Crtical Care 2008 (in press)

Human ARDS

VT

PEEP

Obese patientStroke + Moderate ALI

FRCFRC

V V inducedinducedby PEEPby PEEP

Static P-V Curves at Different PEEPStatic P-V Curves at Different PEEP

Recruited Recruited lung volumelung volume

Nil recruitmentNil recruitmentat PEEP 20 at PEEP 20

Closing pressureClosing pressure

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Maggiore S et al. AJRCCM 2001; 164: 795-801

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Paw (cmH2O)

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Galileo Ventilator's Built-in PV Tool-2

Pressure/Time Ramp 3 cmH2O/s

Pressure/Time Ramp 5 cmH2O/s Piacentini E, Wysocki M, Blanch L.Intensive Care Med 2009.

Nahum A. Yearbook in Intensive Care Medicine. 1995.

Dynamic P-V Curves at Different Flows & Equal Tidal Volume

Inspiratory P-V Curves in ARDS Patients Inspiratory P-V Curves in ARDS Patients with Different CT Patternswith Different CT Patterns

Rouby et al. Intensive Care Med 2000;26:1046Rouby et al. Intensive Care Med 2000;26:1046

LobarLobar

DiffuseDiffuse

PatchyPatchy

Effect of Increasing Resistance during CF.VCVUpward Shift in the Pao(t) Curve

Airway Pressure

Tracheal Pressure

Blanch L et al. Am J Respir Crit Care Med 1995;151:A328

Partitioning of Rrs in Patients (CF.VCV)

Alveolar Heterogeneity during Histamine Challenge

AutoPEEP: Pendelluft Effect

Romero P, Lopez J, Blanch L. Pulmonary mechanics beyond peripheral airways. In: Milic_Emili J, ed. Applied Physiology in Respiratory Mechanics. Springer 1997; p.190-210.

Air TrappingAir Trapping

InspirationInspiration

ExpirationExpiration

NormalNormalPatientPatient

Time (sec)Time (sec)

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w (

L/m

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Air TrappingAir TrappingAuto-PEEPAuto-PEEP

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BeforeBefore

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PEFRPEFR

AfterAfter

Long TLong TEE

Higher Higher PEFRPEFR

Shorter TShorter TEE

Response to BronchodilatorRajiv Dhand. Respiratory Care 2005 (February). Vol 50. Nº 2.

Response to BronchodilatorRajiv Dhand. Respiratory Care 2005 (February). Vol 50. Nº 2.

43210-1.0

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AutoPEEP

Time Time (s)(s)

AirflowAirflow(L/s)(L/s)

AutoPEEP Generation: Lengthen Ti at equal TtotAutoPEEP Generation: Lengthen Ti at equal Ttot(Airflow decreased for a similar VT)(Airflow decreased for a similar VT)

Blanch L, Bernabe F, Lucangelo U. Respir Care 2005;50:110-123

Lucangelo U, Bernabè F, and Blanch L. Resp Care 2005; 50 : 55-65Lucangelo U, Bernabè F, and Blanch L. Resp Care 2005; 50 : 55-65

Progressive increase of inspiratory pause during VCV

INTRINSIC PEEP (PEEPi) in static and dynamic conditions

Flow (l/s)

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DynamicPEEPi (4cm H20)

TrachealPressure (cmH2O)

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END EXPIRATORY OCCLUSION

Respir Care 2005;50(1):110-123

Leatherman JW et al. Crit Care Med 1996; 24:541-546Leatherman JW et al. Crit Care Med 1996; 24:541-546

Expiratory Airway Occlusion in AsthmaExpiratory Airway Occlusion in AsthmaMeasured AutoPEEP = 5 cmHMeasured AutoPEEP = 5 cmH22OO

55

Mechanisms of Auto PEEP Generation

Vieillard-Baron A et al. Crit Care Med 2002; 30:1407-12Vieillard-Baron A et al. Crit Care Med 2002; 30:1407-12

Increasing Respiratory Rate in ARDSIncreasing Respiratory Rate in ARDS

AJRCCM 2000;161:1590-6

PEEP & AutoPEEP in COPD Patients

Blanch L, Fernandez R. In: Mancebo J, Brochard L, eds. Arnette 1996; 329-345.

Ventilator Waveforms at the Bedside

Displays of pressure, flow and volume, and

derived loops are available in the majority of

modern ventilators.

Ventilator waveforms are important to

understand basic respiratory pathophysiology,

and play a role in treatment decisions in

patients receiving mechanical ventilation.