通氣策略-DISEASE-ORIENTED-VE課件(PPT 49頁)

1、DISEASE-ORIENTED VENTILATION STRATEGIES第1頁，共49頁。Objectives of Ventilation ACCP Standards (Slutsky, 1993)CLINICAL1. Reverse hypoxemia2. Reverse respiratory acidosis3. Relieve respiratory distress4. Prevent or reverse atelectasis5. Reverse respiratory muscle fatigue PRIMARYAvoid Iatrogenic Lung Injury

2、第2頁，共49頁。Respiratory Failure PathologyOBSTRUCTIVE (Resistance)AsthmaBronchitisEmphysemaSmoke InhalationSmall ET tubeRESTRICTIVE (Lung Compliance)ARDSPneumoniasCHFPneumothoraxNeuromuscularAbdominal distensionChestwall deformity第3頁，共49頁。Disease-Oriented Ventilation StrategiesObjective: To avoid the ad

3、verse effects of +ve pressure ventilation:barotrauma or volutraumacardiovascular compromiseother complications e.g. overventilation Tailor ventilator settings specific to the pathophysiology of the patient.第4頁，共49頁。Ventilator Settings And HemodynamicsTidal VolumeInspiratory PressureRespiratory Rate

4、I:E RatioPEEPClosed Loop Modes PRVC, ASV, VAPSPathophysiological Status第5頁，共49頁。How Does Blood Return To The Heart ? Venous Valves Muscular Pump“Respiratory Pump”第6頁，共49頁。RESPIRATORY PUMPInspiration - thoracic cavityPressure - abdominal cavityPressure 第7頁，共49頁。MECHANICAL BREATH DELIVERY第8頁，共49頁。Posi

5、tive Pressure Breath Delivery第9頁，共49頁。Mechanical VentilationREVERSES ITIntrathoracic Pressure ?第10頁，共49頁。COPD/AsthmaAsthma airway resistance1. bronchospasm2. airway edema3. secretionsCOPDterminal bronchiole collapse during expirationbronchospasmsecretions (infection) Expiratory Time ConstantAir trap

6、ping & auto-PEEPHyperinflated lungs第11頁，共49頁。CXR - Hyperinflated Lungs第12頁，共49頁。Patient with Airway ResistanceGas flow is greatest where resistance is low, hence overinflation of normal lung units. V/QPvCO2 = 46 mmHgPvO2 = 40 mmHgPaO2 = 70 mmHgPaCO2 = 45 mmHgPaCO2 = 43 mmHgPaO2 = 60 mmHg第13頁，共49頁。12

7、3456SEC120120V.LPMAuto PEEPWhat is it? How do you measure it?第14頁，共49頁。Air trapping and auto-PEEP第15頁，共49頁。Cardiovascular Compromisefrom Auto-PEEPCombination of:high filling pressures (PAP)reduced C.O.hypotensionMistaken for LEFT VENTRICULAR FAILUREContinued ventilation PEA and cardiac arrestMartens

8、 et al, 1993 (Lancet); Kollef, 1992 (Heart Lung); Myles et al, 1995 (Br J Anaesth); Lapinsky & Leung, 1996 (NEJM)第16頁，共49頁。Detecting Auto-PEEP1. Waveforms (Flow, Pressure, Volume)2. Expiratory pause on ventilator (passive patient)3. Diff. b/w pts RR and the ventilators response rate4. Esophageal bal

9、loon pressure5. Central venous pressure line6. Arterial pressure line7. Pulse oximetry (sometimes)第17頁，共49頁。Some cases are very obvious!第18頁，共49頁。Pressure Triggering with Auto-PEEPPatient efforts not recognized by the ventilator-20Paw (cm H20)第19頁，共49頁。Depiction of a patient experiencing no auto-PEE

10、PTime (s)(L/min)123456V.120-120INSPEXHZero flow at end exhalation indicates equilibration of lung and circuit pressure, ie, no auto-PEEPFlow Waveform with Auto-PEEP第20頁，共49頁。Depiction of a patient experiencing auto-PEEP (flow will not move into the lung until PWYE PLUNG)123456V.(L/min)120-120INSPEXH

11、Transition from exhalation to inspiration occurs before expiratory flow returns to zero, ie, auto-PEEP existsTime (s)Flow Waveform with Auto-PEEP第21頁，共49頁。Pulse Oximetry Waveform Depicting Auto-PEEP第22頁，共49頁。Treating Auto-PEEPSuction thick secretions, bronchodilator Tx I:E Ratio 1. RR = expiratory t

12、ime 2. VT (Permissive Hypercapnia)3. Flow rates ?Add external PEEP to 80% of observed auto-PEEP McIntyre, 1997; Ranieri & Giuliani, 1993 Am Rev Respir Dis Flow Triggering to reduce triggering asynchrony第23頁，共49頁。Expiratory W.O.B. and auto-PEEP in the COPD PatientMJ Tobin. NEJM 2001; 344: 1986-96.第24

13、頁，共49頁。PS and WOB during ExpirationPRESSUREEsens allows the clinician to adjust the ventilators onset of expiration to match the patients breathing pattern.FLOWPS overshoots targetEsens fixed 25%Esens adjusted to 50%NormalProblem resolved0100015第25頁，共49頁。Ventilator Settings for COPD/AsthmaPathophysi

14、ology airway resistance and expiratory time constantsVentilator SettingsSIMV or CPAP + PS - better for spont. breathing pt.Low VT, Low RR longer Expiratory TimePermissive HypercapniaReduce patients WOB:PEEP auto-PEEPFlow Triggering第26頁，共49頁。Marik, Chest 1997; 112:1102-1106Acute Respiratory Distress

15、Syndrome第27頁，共49頁。第28頁，共49頁。Fu et al, J Appl Physiol 1992; 73:123-133第29頁，共49頁。Ranieri et al, JAMA 1999; 282:54-61Lung Stretch and BAL Cytokines in ARDS PatientsPatient groups: VT for PaCO2 35-40 mm Hg PEEP to optimize SaO2 with lowest FIO2 (11 mL/Kg; 6.5 cm H2O) PV curve; Pplat lower Pflex (7.5 mL/

16、Kg; 15 cm H2O)BAL for cytokines第30頁，共49頁。MECHANICAL VENTILATIONBiochemical InjuryBiophysical Injury - Shear - Overdistension - Intrathoracic Pressure- Alveolar-Capillary Permeability - Cardiac Output - Organ PerfusionDistal Organs - Tissue injury 2 to inflammatory mediators/cells - Impaired oxygen d

17、elivery - BacteremiaNeutrophilsCytokines, Proteases, Singlet O-, ComplementM MSOF (Slutsky & Tremblay, 1998)Bacteria第31頁，共49頁。Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndromeAmato et al, 1998 N Engl J Med53 Patients with early ARDSRandomly assigned

18、to either Conventional or Protective ventilation strategyAll patients were treated with identical hemodynamic and general support. Conventional Ventilation Protective-ventilation strategyVt 12ml/kg 1:1?第35頁，共49頁。Prevention of Ventilator-Associated Lung InjuryTreat underlying diseaseLimit FIO2 to low

19、est acceptable levelPEEP high enough; Pplat not too highPermissive hypercapniaPressure control ventilationProne positioningRecruitment maneuverInhaled nitric oxidePartial liquid ventilationTracheal gas insufflationExtracorporeal CO2 eliminationSurfactant replacementHigh frequency oscillation第36頁，共49

20、頁。Optimize PEEP using P-V CurveThe greatest resistance occurs at the lowest lung volume (i.e. the distending pressure)Atelectasis may occur in this situation, creating airway collapse at end exhalation第37頁，共49頁。Lung Recruitment ManeuverProlonged high alveolar pressure to recruit collapsed lung units

21、Method used at Massachusett General Hospital, BostonPEEP 30 - 40 cm H2O PC of 20 cm H2O, Rate 10/min; I:E 1:11/2 - 2 minPEEP to maintain recruitment第38頁，共49頁。Recruitment Maneuver32 yr old woman transferred with severe ARDS secondary to streptococcal sepsis: BP 50/30; pH 7.00, PaCO2 78, PaO2 21; PC 3

22、4 (VT 300), PEEP 15, FIO2 1.0, rate 20Recruitment maneuver: PEEP 40, PC 20, rate 10, I:E 1:1 for 2 minDramatic improvement in PaO2 and tidal volumePEEP 25 cm H2O needed to maintain recruitmentExtubated 6 days after arrival; discharged after 2 weeksMedoff et al, Crit Care Med 2000 (April)第39頁，共49頁。Be

23、fore recruitmentAfter recruitment第40頁，共49頁。Lapinsky, Intensive Care Med 1999; 25:1297-1301第41頁，共49頁。CMVIPPVSIMVMMVBIPAPCPAPSPONTPCVVCVAPRVPLVPSASBILVPRVCVAPSPAVWhat About New Modes?Auto ModeAutoFlowPPSVS第42頁，共49頁。What Is BILEVEL? Intermittent CPAP (Dr. John Downs, 1987)CPAP (cm H2O)Time02010第43頁，共49

24、頁。BiLevel Ventilation (Normal I:E Ratios)By setting PEEPH , TH, and respiratory rate close to the patients typical ventilation settings, BiLevel looks similar to PCV/SIMVThis capability has been commonly referred to as BIPAP in EuropeSynchronized TransitionsSpontaneous BreathsPPressure SupportPLPHT4

25、4第44頁，共49頁。What Is APRV?APRV - Airway Pressure Release Ventilationutilizes a very short Exp. time for Pressure Releaseshort time release time allows for CO2 removalAll spontaneous breathing at upper pressure levelSpontaneous BreathsPT“Release” 45第45頁，共49頁。Auto-Flow, PRVC, VAPS and ASVBenefits patien

26、ts who require a target volume, but have variable flow demands and changing lung compliancehelps to avoid barotrauma, IF Pressure Limit setting set correctly by staff840/760 Smart Rise Time is automatic - maintains constant airway pressure despite changes in airway resistance or complianceMajor ProblemFeedback loop used in S300, Evita-4 and Galileo can under support ventilation needs of the patient in some clinical conditions.e.g. acidosis, fever, distress, etc.American Thoracic Society Conference 2000, Toronto - Dr. Brochard第46頁，共49頁。High Press LimitTidal Volume (reference centre)Tidal Volum