波形分析在机械通气的应用.ppt

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1、环路分析在机械环路分析在机械通气中的应用通气中的应用机械通气目的机械通气目的提供足够的肺泡通气量（提供足够的肺泡通气量（V VA A）在安全的供氧浓度下达到适宜的动脉氧分在安全的供氧浓度下达到适宜的动脉氧分压压 胸腔压升高的情况下避免发生气压胸腔压升高的情况下避免发生气压病人舒适病人舒适 合适的呼吸肌负担合适的呼吸肌负担良好的人机同步良好的人机同步进行波形分析的必要性进行波形分析的必要性lPatientventilator dyssynchrony imposes an additional burden on the respiratory system and may increase t

2、he morbidity of critically ill patients.Thille A W,Rodriguez P,Cabello B,et al.Intensive Care Med,2006.32(10):p.1515-22.Ignorance of these issues may prevent the ventilator from achieving its goals and may cause patient harm.Georgopoulos D,Prinianakis G,and Kondili E.Intensive Care Med,2006.32(1):p.

3、34-47.Inspection of pressure,flow and volume waveforms represents a valuable tool for the physician to recognize and take the appropriate action to improve patientventilator synchronyEumorfia Kondili,Nektaria Xirouchaki and Dimitris Georgopoulos.Curr Opin Crit Care 13:8489.Nilsestuen J O and Hargett

4、 K D.Respir Care,2005.50(2):p.202-34;discussion 232-4.Pressure versus TimeInspirationExpirationPaw (cm H2O)Time(sec)TIPeak Inspiratory PressurePIPTEPressure-Volume LoopControlledAssistedSpontaneousVol(ml)Paw(cm H2O)I:InspirationE:ExpirationIEEEIIFlow-Volume LoopPEFRFRCInspirationExpirationPIFRVTMech

5、anical MonitoringComponents of Inflation PressureComponents of Inflation PressureBegin ExpirationPaw(cm H2O)Time(sec)Begin InspirationPIPPIPPplateau(Palveolar)Transairway Pressure(PTA)Exhalation Valve OpensExpirationExpirationInspiratory PauseAirway PressuresStatic or Plateau Pressure静态静态顺应性和平台压顺应性和

6、平台压Separates resistance from elastic recoil吸气末测量吸气末测量Should be kept 10 L/min 常常提示撤机失败常常提示撤机失败VE,VA,and PaCO2800)VAVCO2(PCO2VDVTfVD VEVA222PaCOPECOPaCOVTVD Flow versus TimeThe flow-time curve can be used to detect:Waveform shapeType of breathingPresence of Auto-PEEP(Intrinsic PEEP)Patients response t

7、o bronchodilatorsAdequacy of inspiratory time in pressure control ventilationPresence and rate of continuous air leaks判断流速波形判断流速波形Inspiratory flow patterns can vary based on the flow waveform setting or the set breath type as illustrated减速波减速波不同类型呼吸下，五种类型的流速不同类型呼吸下，五种类型的流速-时间时间曲线曲线评估支气管扩张剂的反应评估支气管扩张

8、剂的反应effect of inspiratory time in pressure control on flow delivery to the patient.may be desirable in some cases患者对支气管扩张剂的反应性患者对支气管扩张剂的反应性BeforeTime(sec)Flow(L/min)PEFRAfterLong TEHigher PEFRShorter TE漏气对漏气对吸呼切换的影响吸呼切换的影响：漏气会导致：漏气会导致吸气流速下降缓慢吸气流速下降缓慢，达不到预设的切，达不到预设的切换标准（换标准（set termination threshold）

9、吸气峰流量吸气峰流量Tinsp45%15%Threshold can not be reachedthe period of mechanical inflation must match the period of neural inspiratory time(the duration of inspiratory effort),and the period of mechanical inactivity must match the neural expiratory time While the ventilator was still pumping gas into the p

10、atient,his expiratory muscles were recruited,causing a bump in the airway-pressure curve.That the flow never returned to zero throughout expiration reflected the presence of autopositive end-expiratory pressure.Auto PEEP吸呼切换延迟吸呼切换延迟Delayed termination present患者患者呼气肌开始活动呼气肌开始活动时，呼吸机的吸气过程时，呼吸机的吸气过程还未完

11、成，因此发生亚临床的人机对抗还未完成，因此发生亚临床的人机对抗。Note there is also a small airway pressure spike near the end of mechanical inflation,which coincides with the patients neural expiratory activity.切换延迟切换延迟Cycle Criteria?吸气预置流速不足吸气预置流速不足Flow(L/min)Time(sec)NormalAbnormalPatients effort吸气预置流速不足或者患者主动吸气吸气预置流速不足或者患者主动吸气(

12、SIMV)/volume-limited/pressure support approach“double breathing”assist volume control 恒定流速恒定流速患者持续吸气，气道压力患者持续吸气，气道压力下降下降，在呼气阀打开时，在呼气阀打开时，发生发生double breathingAir TrappingInspirationExpirationTime(sec)Flow(L/min)Air TrappingAuto-PEEPPRESSURE-TIME CURVESBreath type delivered to the patientWork required

13、 to trigger the breathBreath timing(inspiration vs exhalation)Pressure waveform shapeAdequacy of inspirationAdequacy of inspiratory plateauAdequacy of inspiratory flowResults and adequacy of a static mechanics maneuverAdequacy of the Rise Time settingBreath type delivered to the patientBreath type d

14、elivered to the patientCMV,with auto-flow onMeasuring Static Mechanicsillustrates a stable static pressure plateau measurement that differentiates the pressure caused by flow through the breathing circuit and the pressures required to inflate the lungs.The pressure-time curve can be used to verify t

15、he stability of the plateau when calculating static compliance and resistance.C 代表不稳定的气道平台压代表不稳定的气道平台压力，常见原因为漏气或者患力，常见原因为漏气或者患者出现自主吸气者出现自主吸气Assessing Rise Time 吸气斜率吸气斜率Chiumello D,Pelosi P,Croci M,et al.,Eur.Respir.J.,2001.18(1):p.107-114.A the rise to pressure may be too slow.B ideal waveform 恰当的斜恰

16、当的斜率设置率设置C A rise time that is too fast流速不足流速不足 Adequate FlowInadequate FlowPaw (cm H2O)Time(sec)Inadequate Flow 预置流速不足预置流速不足The dished-out appearance of the airway pressure waveform illustrates the changes from the passive breath when flow does not meet patient demand.Progressive increases in patient effort during breaths 2 and 3 were created by manually lifting the test lungTriggering difficulty and unnecessary patient work 触发困难触发困难第三次为患者触发的通气，第三次为患者触发的通气，虽然患者触发了呼吸机，但虽然患者触发了呼吸机，但是是P-TP-T曲线呈下凹型