SIMV vs SIPPV

[drbidhupillai]

Does any one please tell me when you chose SIPPV??.IS it a better mode of ventilation than SIMV to wash out CO2,Can it be used in first place itself than SIMV when we ventilate a baby for RDS/MAS ????

[Guest adspi]

Can those answering this interesting question make reference to SIMV and SIMV/PS instead of SIMV only?

Thank you very much.

[goosman]

We never use SIPPV. The reason for this is that there is a risk of hyperventilation and airtrapping. I think the only theoretical advantage of SIPPV over SIMV is that every trigger will be awarded with a breath leading to less stress, as opposed to SIMV, in which only the set frequency will be rewarded with a breath. This can be handled by combining SIMV with PSV, however with this mode there also is a risk of hyperventilation since the infant will receive a breath with every trigger. Of course this risk can be minimised by carefull observation of tidal volumes and minute volumes and by inline ETCO2 measurement. A specific risk when using SIPPV in infants with MAS is air-trapping: when expiratory times are too short for a complete exhalation (as shown by the flow-time curves) the infant will build up inadvertant PEEP with a risk of pneumothorax. This risk is very low in RDS since inspiratory times can be relatively short in the non-compliant lung, so you get more time for each cycle.

In our NICU we mainly use SIMV with typical frequencies of 40 - 60, dependent on gestational age, the breathing frequency of the infant and the respiratory mechanics. In full terms we sometimes use PSV as a weaning mode. Personally I think combining PSV with some kind of volume controlled mode is preferable, but these kinds of ventilation modes depend greatly on the abillity of the machine to compensate for tube leakage.

However, all ventilatory strategies should be chosen with one goal in mind: to minimize side effects of artificial ventilation (chronic lung disease, air leaks, intra ventricular hemorrhage, leucomalacia). In literature, to date I have found no evidence of SIPPV or PSV being superior to SIMV in this aspect. What literature does show is that caregivers should concentrate on patient-triggered ventilation or HFV and stick to the chosen mode. Building your experience with the chosen mode of ventilation might yield the best results.

Best regards,

Christ-jan van Ganzewinkel

Neonatal Nurse Practitioner

Máxima Medical Centre, Veldhoven

The Netherlands

[Guest adspi]

Is there a real risk of hyperventilation with SIPPV if the ventilator being used is a Dräger Babylog 8000 which offers Volume Guarantee!?

[goosman]

My experience with the Drager machine is somewhat limited, since we have mainly used SLE the last years. We still have some Babylogs 8000 plus, but they are mainly gathering dust. To my knowledge hyperventilation can still occur when using volume guarantee combined with SIPPV. Volume guarantee with the Babylog (as I recall) is set with tidal volume, not minute volume. To my knowledge the machine does give an alarm when minute volumes are too high (this alarm has to be set by the user). So if the alarms are set correctly the risk should be low. If the minute volume alarm is set too high the patient is able to hyperventilate by means of a high breathing frequency.

Hope this answer helps !

Best regards,

Christ-jan