1、NEWER VENTILATORSWHAT MAKES THEM DIFFERENT ?John Newhart CRTT. RCP.PURITAN BENNETT MA-1Puritan Bennett MA-1 First released August 1967. Simple to use Basic IMV system (non-sync). Bellows spirometer for exhaled gas measurement.SIEMENS 900 CSIEMENS 900 B/C 900 B available in the USA early 70s. Time li
2、mited and minute volume preset. Patient or time cycled or SIMV. Expiratory flow monitoring.BEAR I Built in SIMV. Monitoring of tidal and minute volume. Pneumatically and electrically powered, electrically controlled volume limited. Time or patient cycled, control or assist/control modes.PURITAN BENN
3、ETT 7200 Released 1983 First widely accepted microprocessor controlled ventilator in USA. Software upgradable. Newer Generation VentilatorsTRANSPORT VENTILATORSEARLY MODELPULMONETIC LTV 1000PULMONETIC LTV Compact lightweight 12.6 lbs. Ability to transport more critical patients. Internal battery. Vo
4、lume Control, Pressure Control and Pressure Support. Volume and pressure alarms and monitoring.Changes in Ventilators Include. More sophisticated hardware. More compact size. Multiple high speed microprocessors. Backup battery systems. Graphical User Interface (GUI). An ever expanding list of modali
5、ties.Modular DesignuTouch Screen Display can be mounted separatelyuBreath Delivery Unit weighs only 40 lbs. can be mounted separately from cartNew Hardware Proportional control valves Active Exhalation valves Battery backup Miniature blowerProportional Control Valves One or two valves (O2, Air, or b
6、oth) proportionally open or close to control the flow of gas to the patient circuit. Responsible for FIO2, Flow rate, Flow waveform. Microprocessor controlled. Each valve is controllable from 1,000-4,000 steps.Two Proportional Valve SystemNPB 7200-840, DRAGER E2-4, SERVO 300O2AIRTo Patient50 psig50
7、psigEach gas has its own solenoid, flow sensor and pressure regulator . Both valves controlled by microprocessor.FLOW SENSORFLOW SENSORSingle Proportional SystemHamilton Veolar, Bird 6400-8400st O2AIRTo Patient50 psig50 psigBLENDERRESERVOIR10-15 PSIGAir and O2 are mixed in a blender, stored as a mix
8、ed gas in a reservoir then pass through a single proportional valve.PROPORTIONAL VALVEPneumatics Chassis (PB 840)Blower with Intragral Digital BlenderO2Pulmonetic LTV Turbine/Blender SystemBlended gas to patientDelivery Control ValveActive Exhalation Valves The inspiratory and expiratory valves are
9、active during inspiration to maximize the reproducibility of inspiratory and expiratory events. These valves are critical in newer modes such as APRV, BiLevel, and ATC. With an active exhalation valve, the ventilator moves the exhalation valve off of its seat during exhalation. With a non-active val
10、ve the patient must push the valve off of its seat adding to expiratory resistance and work of breathing.Active Exhalation ValveDuring inspiration, the valve is closed with the force of the insp pressure setting Allows coughing or spont breathing at upper pressure level by venting excess pressure an
11、d flow (PCV or BiLevel)40PCIRCcmH2OINSPLminEXP302010 010-2080604020020-804060V.04812s2610Spontaneous EffortsSpontaneous EffortsPCV W/O Active ValvePCV with Active ValveTwo Proportional Valve System With Active Exhalation ValveO2AIR50 psig50 psigAir and O2 solenoids combined with active exhalation va
12、lve.PATIENTEXHMicroprocessor Control Each new generation of ventilator incorporates faster processors. Multiple high speed processors improve the ventilators response to the patients needs. Faster processors make more information available to the clinician.MICROPROCESSOR FUNCTION During each breath,
13、 the ventilator switches through multiple algorythims. These determine sensing of patient breath, rise rate of breath, criteria for patient termination of breath at various points during the breath, and ventilator initiated termination of breath. Monitored data as well as data needed for ventilator
14、function are constantly being processed in the background. Most calculations done by the ventilator are never seen by the user. Most modes of ventilation that have come out in the last 15 years would be impossible without computer control.UPGRADABILITY Older ventilators frequently required a complet
15、e factory overhaul to have one mode added. Upgrading newer ventilators is usually accomplished by software upgrade. This may be done by changing out the chip set or uploading software from a PC. Adding options/modes typically involves changing a chip that accesses specific options included in the so
16、ftware, or entering a code number through a keypad. Battery Back-Up Is now standard on most ICU ventilators. Eliminates interruptions in ventilator function during flickers or short term failure in A/C power. Aids patient safety.GUIGraphical User Interface Touch screen technology. Becoming the norm
17、for ICU ventilators. Replaces traditional knobs, buttons etc. Blends graphical displays with controls. Easy software upgrades. Gives additional information relative to setting changes.Ease of Use - Software Controlled ScreensOnly current modes and settings are displayed (ease of use)Information can
18、appear as needed to help make decisions easier and saferAutomatic Tube Compensation Overcomes the resistance to flow created by an endotracheal tube or tracheostomy tube. Gives the patient the sensation that they are not intubated. Most important during spontaneous breaths. May provide a calculated
19、tracheal pressure curve on the graphics display (E4). Can be used to “train” the respiratory muscles.ET. Tube Resistance During Breath Types Mandatory breaths from the ventilator easily overcome the resistance of an ET. tube. Spontaneous breaths are more difficult as a result of breathing through a
20、relatively small orifice.ATC Function During Inspiration During inspiration , the ventilator increases pressure at the top of the ET. tube proportionate to the inspiratory flow rate.Function of ATC during Exhalation During expiration the circuit pressure is decreased below the PEEP level. The trache
21、al pressure is held constant at the selected PEEP level. This decreases the work of expiration. The circuit pressure is calculated from the expiratory flowrate. ATC with Paw and Ptrach waveforms displayedPressure CalculationUsing the flow measured by the ventilator, the difference in pressure at any
22、 given time can be calculated by the following equation:Pressure = Rtube Coef. X Flow2, where tube resistance R is itself dependent on the flow.Difference Between ATC and PS PS is a user set, fixed pressure that remains constant throughout the inspiratory phase irrespective of the patients flow rate
23、. ATC is a user set level of compensation (1-100%). The driving pressure will vary according to the E.T. tube size set, compensation level and inspiratory flow rate.CONCLUSIONVentilator Design The design of ventilators depends increasingly on the use of microprocessor control and software. The hardw
24、are in ventilators is being continuously miniaturized. Move towards ventilator designs that will ventilate infants through adults.CONCLUSIONModes of Ventilation Modes and hardware that minimize the overall work of breathing. Modes that make “decisions” based on both input from the therapist and patient monitoring. Interfaces that display more graphical and numerical information. “Smart Alarms” that look for combinations and severity of thresholds. The alarm indicates by sound and/or graphics the seriousness of the condition.
