Lecture 22 - syringe drivers Flashcards
describe the subcutaneous tissue.
Subcutaneous tissue thickness is generally greater in females than males
Subcutaneous tissue thickness increases as the BMI increases
what are common anatomical sites for subcutaneous administration?
anterior - abdomens in the umbilical region , thighs,
posterior - posterior aspect of the upper arm, lower loins, back
what are advantages and disadvantages of subcutaneous route?
Advantages
Versatile route of administration
Does not necessarily require trained personnel
Disadvantages
Absorption rate SC < IM < IV
Inter- and intra-patient variation in absorption rates e.g. in response to heat, massage or drugs
Injection volume limited to around 1 ml
Additional formulation constraints e.g. pH and tonicity
what are the formulation consideration for sc route?
If formulation is at extremes of pH then you must ensure that formulation can be diluted at an appropriate rate to minimise irritation/tissue damage at injection site
Formulation pH for intravenous route 2 - 12
Formulation pH for intramuscular route 3 - 11
Formulation pH for subcutaneous route 3 – 8 (narrower due to reduced vascularity)
what is formulation tonicity?
Formulation tonicity (osmolality) is dependent on the properties of the constituents and the number of products in solution
Risk of tissue damage or irritation is related to actual osmolality and residence time of formulation in tissue
what are syringe drivers?
Syringe drivers are portable, battery-powered devices designed to continuously deliver SC medication over prolonged periods of time (usually 24hrs) at fixed rates
- Useful when small volume of drug(s) are need to be infused at a slow rate
- Compact design enables patients to move around and maintain independence
Used in community and hospice settings for treatment and control of symptoms associated with chronic or palliative conditions
Used in hospital settings for treatment of patients who are comatose or unable to manage/tolerate oral medication e.g. malabsorption syndromes, dysphagia, intestinal obstructions
what are advantages of syringe pumps?
Increased comfort as repeated injections are not required
Control of multiple symptoms with a combination of drugs
Round-the-clock comfort because plasma drug concentrations are maintained without peaks and troughs, giving constant therapeutic drug levels over a 24-hour period
Mobility maintained because the device is lightweight and can be worn in a holster under or over clothes
Generally needs to be
loaded only once every 24 hours
what are disadvantages of syringe drivers?
Staff training
Possible inflammation and pain at the infusion site (drug(s)/formulation dependent) and potential source of infection (low incidence)
In emaciated patients or those on long-term infusions skin-site availability may become a problem (rotate infusion site)
Lack of reliable compatibility data for some mixtures of medications
Daily visits from district nurses and/or other health professionals may be too intrusive for some patients and family.
what is the CME Mckinley T34 device?
most widely used device across NHS
Met NPSA specifications but has additional safety features
- Infusion rate cannot be altered once the device is infusing
- Device has a syringe size detector
trained registered nurse can set up syringe pump.
each pump opened from lock case.
3 detection points. should be clean nd undamaged, battery is secured.
tun on syringe and allow preloading check.
check battery level by pressing info and yes should be 35% or above.
line syringe around
how to insert sc line?
on shoulders, abdomen or thighs.
wash and dry hands, put gloves on.
clean area with alcohol swab and let area dry.
sharp and logest part of needle at the bottom, in contact with skin. hold with wings, point at 45 degree angle and go in a few mm and flatten needle push forwards until butterfly reaches skin.
use wigs to secure needle in place. put dressing over wings to hold in place.
pull and away to remove needle.
call hospice if there is blood in tubing. remove clear cap and replace with purple cap.
what are Syringe driver considerations and issues on mixing ingredients?
Instability
Incompatibility
- Physical incompatibility
- Precipitation
Sorption Phenomena
Photo Degradation
Chemical Degradation
how does instability affect the syringe driver?
Applied to chemical reactions that are irreversible
Result in different chemical products
Inactive
Toxic
Common reactions include hydrolysis and oxidation
what does incompatibility in syringe drives complication refer to?
Generally refers to physicochemical phenomenon
Concentration-dependent precipitation
Acid – base reactions
Often manifest in visible changes
- Precipitation
- Turbidity/haziness
- Colour changes
- Viscosity changes
- Effervescence
- Phase separation
what are common types of physical incompatibility?
Usually related to solubility changes or container interactions
A drug will remain in solution if its solubility does not exceed its saturation solubility
If it exceeds its saturation solubility precipitation (crystallisation) can occur – time can be erratic and unpredictable
