Improved Patient Control Analgesia (PCA)
Continuous basal flow combined with a PCA option is considered as an improved setup to administrate CPNB; improved correlation between the actual pain level and medication consumption and reduced total medication consumption.
A. Clinical Rational
1. Pain level varies during recovery; during the same day patient may experience moderate pain followed by severe pain and then again
2. Typically, severe pain is experienced when patient moves (exercise, ambulate)
3. PCA enable to continuously administrate law basal rate of medication (suitable to anaesthetize moderate pain) while patient
activate the PCA (administrate additional bolus of medication) when severe pain is experienced or prior severe pain is experienced
(i.e. add medication bolus priorexercisin or ambulating)
B. Users population:
PCA administration is applicable only for those who are (i) physically capable to activate the PCA device be used (ii) mentally, may be
educated to use such administration (mainly focusing on not activation when not required other than "activate anyway any time").
C. Parameter influence the clinical efficiency of the PCS bolus
1. Bolus volume;
The volume that will be infused once the patient activate the PCA device.
2. Bolus velocity:
(The velocity of the infused bolus of medication).
This parameter influence the medication spread.
There aren't public domain clinical studies that analyzing the bolus anaesthetization vs. injection velocity, but there are many clinical
indications that evidence that for PNB, manual bolus (performed by the anesthesiologist) is superior over PCA bolus.
Several published studies indicate that the velocity of manual PNB injection is between 10ml/min to 30ml/min.
3. Lockout time
The minimum allowable time (locked by the pump design/programing) between two consequent boluses.
D. Velocity of typical PCA PNB bolus
The actual velocity of PNB bolus infused by infusion pump (manual, elector mechanical) is in the range of 1.5ml/min to 3ml/min; depending
on the pump design and the ID and length of the catheter.
1. All today used infusion pumps are basically designed for IV infusion and therefore aren't capable to create the sufficient pressure to
infuse the medication through the NB catheter at a similar velocity to a manual injection.
E. MultiBolus II™ (MBII)
The MBII is the only PCA device that was designed to address the unique requirements and needs of PNB bolus administrated through
catheters in the range of 18G to 21.5G
1. Currently, the MBII is the only cleared PCA device that is capable to infuse the bolus medication at relative (to other PCA devices) high
velocity; 6ml/min to 9 ml/min depending on the design of the NB catheter.
Relying on published studies and on the MBII features; the MBII bolus velocity is almost as the low rate velocity
of the manual NB bolus.
2. Based on so far clinical evidences (not studies) patient reporting on pain relief within several minutes
after activating the MBII other than about 30 minutes with typical bolus device.
3. Clinical benefits;
> Improved pain therapy
> Reduce consumption of complementary medication
> Improved patient experience and higher patient satisfaction.