Recently we have upgraded our fleet of PB840 ventilators to include this mode of ventilation.

Has anyone out there had much experience with PAV?

I want to restrict my thoughts at this time except to say that I have had it on about 4 patients. I am far from an expert but do believe this to be a valuable mode of ventilation. Having had multiple opportunities to use PAV on the Respironics Vision as a NonInvasive mode, the 840 seems to take PAV lightyears beyond. It seemed that with the Vision one would have to rely heavily on patient feedback to make an educated guess as to where to set the Volume and Flow assist. With the 840 the guesswork is gone. The processor computes a Cpav and Rpav using formulas far beyond my scope of thought and a .3millisec breathhold over 4 breaths or so to actually calculate the volume and flow assist. From there it is only a matter of weaning the % of PAV to maintain the patient until extubation. This is made feasable by a WOB line which displays WOBtot and the WOB patient. It is a useful tool in determining where to set the % PAV to ensure the patient is either resting or working as required.

Having already seen PAV in action with the Vision, despite the guesswork in determining a level for volume and flow assist, the patients Compliance and Resistance were seemingly better accounted for than with BiPAP. PAV on the Vision seems to me like a fine tuning for IPAP considering how the pressure will be delived to account for compliance and resistance. With the 840 the added benefit is the guesswork is not only gone but it is monitored and adjusted on an ongoing basis.

Is that what you call restricting your thoughts? I personally like PPS

So Im not so good at restricting my thoughts . It is a pretty cool mode though. I found some info in Tyco's website in Eastern Europe. There didnt appear to be much info on the N.American website. http://www.tycohealth-ece.com/index.php?folder=64

OK I'm going to play devil's advocate here. But I don't intend to pick on just PAV, but rather all the newer automatic adjuncts for support and "weaning". PAV, Smartcare, Automode, MMV, etc.

Since the new consensus statement on mechanical ventilation discontinuation (

Consensus Guidelines)

basically lays out two goals for us

1) keep the patient on a stable and non-fatiguing mode of mechanical support
2) when the patient meets certain CLINICAL criteria (i.e. body temp, FIO2, etc. and NOT NIF or VC, etc.) perform a spontaneous breathing trial from 30-120 minutes. If they pass extubate (unless airway issues--but then the "weaning" isn't an issue). If they fail return to stable and non-fatiguing mode.

So why do we need any of these modes? If we are too busy to adjust and perform the above then maybe we (in the global sense--society) don't have any business placing people on mechanical ventilation.

Can't the above two goals be met with the current modes and adjuncts on mechanical ventilators? Can not the current clinical RT's assure both of the above with the tools and staffing on hand?

Does PAV help to provide a "stable and non-fatiguing" mode? Or is per cent reduction now going to be viewed as a return to "weaning" march of what should be the past? Does Smartcare help us to provide a better support mode, or a better spontaneous breathing trial?

Has our technololgy overshot our current best consensus guidelines?

Also, for every one of these modes I think it is pretty critical that every RT knows pretty much what the ventilator does to come up with it's resultant settings/actions. Not necessarily describe in a full mathematical formula. But I'll just bet in every one of these there is a certain patient/mode combo which could cause a problem. It may be ironic that the complications of the modes have outstripped our profession's (and that of RN's and MD's) current clinical ability to troubleshoot problems when the mode's "wisdom" doesn't interface well with patient action.

For instance, when Automode works behind the scenes I've seen many instances where some of the RT's had no concept that what the patient was on was essentially Pressure Control. Then when things weren't stellar (i.e. ARDSnet VT's) the troubleshooting was deficient.

Ooops in the above last paragraph meant Autoflow and not Automode.

But Automode in Servo 300A gave PS with 5% exp flow termination. It would have been better to just keep the patient in PRVC and adjust the Insp. Time to match the patient.