SIMV or SIPPV

[Guest sameera_reddy]

Which is a better mode of ventilation SIMV+VG or SIPPV+VG in a 1 kg 28 week neonate post Surfactant with Fi O2 > O.5 and PaCO2 of 34

[rehman_naveed]

If newly born , SIPPV with VG is better, Since your Baby is washing PCO2, needs to put on Lower VG i.e 3.5 or even 3 ml/kg, and monitor blood gases, if still washing PCO2, remove VG and decrease the PIP to 13 or 14 and keep on monitoring blood gases till u get good blood gases.

Initially SIMV is not a good mode, as it will only support the preset breaths, and will make the baby to work hard

[Guest hamakoosha]

bbb

[Guest hamakoosha]

we cannot talk about VG without putting minute ventilation in our minds, as being composed from rate & tidal volume...An agitated, distressed neonate tends to adopt higher rates using higher than normal efforts still failing to gurantee for himself a reasonable tidal volumes ( disease affects his alveolar compliance---not his respiratory center), trying at least to get a fair minute ventilation to escape early resp. failure.Now, ventilators can give u the opportunity to control & target a desired minute ventilation......Dr.Rehman hit his target very HARD...depending on SIPPV will assist all ventilator sensed breath trials, which will not leave unsupported breaths, still guranteeing a low tidal volume will not aid in co2 wash...minimising the commonly faced respiratory alkalosis in SIPPV mode (laking VG option) .BUT to answer u correctly, u had to tell us the clinical condition of ur neoborn after surfactant administration or latest x ray finding...cus if ur baby started to take the regressive course early( co2 is within reasonable limits, spontaneous resp rate??), u can surely start SIMV ventilation---not SIPPV--- immediately, synchronising 80-95% of his spontaneous breaths will not make him fatigue( especially when breathing against a constant EEPP), on the contrary, it will be a preparatory step to initiate the weaning phase.As i told u u had to tell us clinical status for ur baby post surfactant.

[Guest sameera_reddy]

we cannot talk about VG without putting minute ventilation in our minds, as being composed from rate & tidal volume...An agitated, distressed neonate tends to adopt higher rates using higher than normal efforts still failing to gurantee for himself a reasonable tidal volumes ( disease affects his alveolar compliance---not his respiratory center), trying at least to get a fair minute ventilation to escape early resp. failure.Now, ventilators can give u the opportunity to control & target a desired minute ventilation......Dr.Rehman hit his target very HARD...depending on SIPPV will assist all ventilator sensed breath trials, which will not leave unsupported breaths, still guranteeing a low tidal volume will not aid in co2 wash...minimising the commonly faced respiratory alkalosis in SIPPV mode (laking VG option) .BUT to answer u correctly, u had to tell us the clinical condition of ur neoborn after surfactant administration or latest x ray finding...cus if ur baby started to take the regressive course early( co2 is within reasonable limits, spontaneous resp rate??), u can surely start SIMV ventilation---not SIPPV--- immediately, synchronising 80-95% of his spontaneous breaths will not make him fatigue( especially when breathing against a constant EEPP), on the contrary, it will be a preparatory step to initiate the weaning phase.As i told u u had to tell us clinical status for ur baby post surfactant.

[Guest sameera_reddy]

The clinical condition of the baby was X-Ray still showing RDS but lung volumes are better,RR50-60/MIN,no signs of sepsis.I am very much aware that SIMV is superior in the context but the hitch is the weight of the baby.Being small the tiring out phenomenon is a higher risk here and also the possibility of an IVH if distress continues.When we talk about VG-Volume guarantee we are directly targetting the minute volume and infact that is the reason why we use VG.We have been using both these modes successfully on many neonates(>1000 of them) in the past 7 years and we have also been using PSV and SNIPPV also in different groups.

The reason for this discussion is to have suggestions from the experienced forum if any thing regarding the inspiratory time,flow could be altered in SIPPV to counter the hypocarbia happening to prevent PVL in future

[Guest hamakoosha]

My greetings to you…its my pleasure to see ur reply… Choosing an approprite Inspiratory time will not differ in both modes as u know, but It rather depends upon his own respiratory rate , I:E u want to choose. In PC modes usually I first choose an IT setting that is very synchronised with baby own IT, lying between 0.3- 0.38, that will minimise expiratory asynchrony with the ventilator giving the advantage to appropriate diaphragmatic contractility. After that I choose appropriate peak inflating pressure that will give me a reasonable tidal volumes, raesonable chest expansion & fair air entry.( most my colleages choose PIP first, I choose IT first).Of course if u r operating on a pure flow\volume control ( I use crossvent-biomed) choosing an appropriate tidal volume will be more easier & constant by calculation of constant insp. flow rate & insp. time . So choosing a flow rate will depend upon IT u choose best for baby.Volume gurantee is a valvular\ pressure controller,with a variable PIP and peak inspiratory flow depending on variable PIP(according to choosen target vol.) and resistance met, followed by a decelating flow that will depend on lung tissue characteristics ( time constant).

U have been using vol. gurantee for 7 years, a much valuable experience I admire.

There is a dual mode used in adults PSVA where u can select a flow value to b a cut point to change breath (from pressure control\decelerating flow)to b on a constant flow to target a preselected value of delivered volume.

IT & expiratory synchrony are very important items in setting assesment, their importance showed up since a while , many were talking about most appropriate cycling criteria, an era in which PSV dominated carrying a great hope for better cycling and exp synch…. Now PAV & specially NAVA carry much of hope in giving assist appropriate for neural insp. time…

For hypocarbia, do u know textbooks preset values for minute ventilation to target alevel of PaCO2?i think proportionating MV & PaCO2 will yield better results,, I mean that for a fixed ((low))tidal vol. and still hypocarbic,, u ll v to choose a percentage of spontaneuos breaths to support ( SIMV) rather than VG AC,,usually 80-95%,, but getting the correct rate is easy by simple equation…

It is my pleasure again & I wish ur baby is doing well.i m waiting to hear about him.