Transcript Practical Problems in Pediatric Parenteral Drug Administration

Practical Problems in Pediatric
Parenteral Drug Administration
• Pediatric needs vary from adults due to:
• smaller dose volumes (smaller doses based
on body wt. or body surface area)
• reduced fluid requirements (as per organ
function + excretion rates)
Subcutaneous Injections
Use intermittent: insulin, heparin,MMR
vac.
continuous: morphine,
deferoxamine
• 5\8 inch, < 25 gauge needle
• 1.5 mL max volume
• into the thigh of infants or deltoid area of
older children beneath skin and fat but
above muscle
Intramuscular Injections
Use:
• medications that are irritating if given sc
• faster absorption and larger volume than sc
• if IV route not available for some meds
• compliance if patient not taking oral meds
• administration of vaccines (i.e..DPT polio)
Intramuscular Injections
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23 gauge, 1 inch needle
3 mL maximum volume (5mL in adults)
0.5 mL max. volume for deltoid area
infants - anterolateral thigh provides largest
muscle mass or the rectus femoris (more
painful) - avoid medial thigh due to major
blood vessels and nerves
Intramuscular Injections
• 2-3yr - the ventrogluteal area (not into
buttock due to sciatic nerve) or deltoid area
• older children - the deltoid muscle or the
posterolateral aspect of the gluteal area
(not into buttock)
Injecting Subcutaneous
Medication Via An Insuflon
Use:
• Many sc medications: i.e. heparin, low
molecular weight heparin, DDAVP,
filgrastim (G-CSF), and interferon
• Used in adults for insulin administration
• Not appropriate for all drugs: i.e. growth
hormone as induration around insuflon will
occur
Advantages of SC Administration
via an Insuflon
• Catheter dead space is very small 0.0075mL
• Flush medication into patient with small
amount of compatible solution if necessary
• 7 days max. indwelling time(3 days for
insulin in adults)
• rotate insertion sites to avoid tissue damage
• allows daily sc administration into canula
without daily needle poke
Advantages of Intravenous Injections
• Complete and rapid drug absorption with
rapid onset of action
• Immediate access to cardiovascular
system
• Useful in neonates with little muscle
mass
• Less painful route for frequent injections
• Administer drugs which cannot be given
by another route
Disadvantages of IV Route
• Rapid drug/fluid delivery means immediate
onset of adverse reactions and inability to
withdraw infused solutions
• Risk infusion of air, microorganisms,
pyrogens and particulate matter
• Risk sepsis (infection), phlebitis (venous
irritation), extravasation/infiltration (leaking
outside of the vein)
IV Access Sites
• Peripheral Sites:
-vein in hand or forearm
-scalp vein or foot vein in infant (possible but
central IV site preferred in neonates)
• Central IV Sites: subclavian vein into superior
vena cava
-central line inserted peripherally
-umbilical vein in neonates
Central Venous IV Line
www_geocities_com-lambda_med-medical_art_previews4_gif.htmCentral Venous IV Line
Factors Influencing IV Drug
Delivery
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small dose volume
slow infusion rate
dead space volume
drug specific gravity
infusion device used
Small Dose Volumes
• many pharmaceutical manufacturers do not
provide suitable concentrations of meds for
pediatric administration
• require prior dilution in order for dose to be
measurable (ie. Dose volume < 0.5 mL)
• potential for dosing errors secondary to
unsuitable drug formulations and dilution
procedures
Drug
Available
Conc.
.
Dexametha 4mg/mL
-sone
Digoxin
Diluent
Final Conc.
NaCl 0.9% 0.4mg/mL
dose<0.4mg
50mcg/mL NaCl 0.9% 10mcg/mL
Tacrolimus 5mg/mL
dose<5mcg
NaCl 0.9% 0.5mg/mL
dose<0.5mg
Small Dose Volumes
• accurate dose measurement (i.e. with
appropriate syringe)
• small syringe with integral hubless needle
for volumes < 0.5mL
• provide 0.05 mL drug overfill in syringe to
fill needle hub if needle must be attached
(include overfill information on label)
When Dose Volume is Less Than Fluid
Volume in IV Tubing
• Provide medication device with 24hr drug
volume + extra volume equal to tubing loss
• change tubing and prime with fresh supply
of drug Q24h
• after 24h - tubing is discarded for infection
control and because the drug in the tubing
has reached it’s expiry time
• drug must be stable in selected diluent for
24h at room temperature
Slow IV Infusion Rates
• cause an increase in the time required to deliver
the dose
• Slow/low flow rates (1-10ml\hr) commonly used
with neonates and fluid restricted patients
• potential for drug to disperse or layer out within
macrobore IV tubing when IV flow rate is slow
(use microbore tubing instead)
• use of microbore (low volume) tubing (diameter
0.06 - 0.14 cm) will minimize this effect
Residual Volume (Dead Space)
• > 0.05 mL of volume found in hub of
needle, stopcocks, Y-type or T-type injection
ports or in-line filters
• overdosing by 0.05 mL may occur if syringe
is milked
• under dosing by 0.05 mL may occur if
needle is changed after the exact dose is
measured (dosing error =5% for a 1 mL
dose volume)
Dead Space
Drug Specific Gravity
• in slow moving fluid, the specific gravity
can cause the drug to settle, float or pool in
a bend of IV tubing and not be administered
on schedule
IV Infusion Devices
• large volume (e.g. Gemini) or small volume
(e.g. CADD) infusion pumps
• syringe pumps are accurate for small volume
delivery
• volumetric infusion devices (Buretrol) used for
small total fluid requirements and slow rates of
administration
• choice of device also depends on frequency of
dose (ie.intermittent vs continuous infusion),
whether the drug or its vehicle requires special
containers and administration sets,and the latex
allergy status of the patient.
Health Risks Caused By DEHP
• Affects developing reproductive tract
(testes) of male fetus, male infants and
potentially of pre-pubertal males
• infants especially premature infants more
susceptible to toxic effects
• cardiac toxicity - may affect cardiac
transplant patients of all ages
• patients receiving multiple transfusions for
trauma, hemodialysis patients also at risk
LEACHING OF PLASTICIZER (DEHP)
• Medications which are lipophilic or are in
vehicles containing lipophilic surfactants
(e.g. soy oil emulsion, polysorbate 80) leach
significant amounts of DEHP from PVC
containers & administration sets
• Use glass bottles, polyolefin IV bags
(P.A.B. IV bags-B Braun Mc Gaw), ethyl
vinyl acetate (EVA) IV bags, polyethylene
lined PVC administration sets, or
polypropylene syringes.
Drug Incompatibility with Infusion Device
• adsorption of drug onto plastic or glass
infusion device
• a significant portion of the dose may be lost
to adsorption if very dilute solutions of the
drug are infused
• flush device and tubing first with drug
infusion solution to saturate binding sites
prior to starting infusion
• choose low sorbing administration set &
tubing , titrate the dose to clinical response
Volume Control Set (Buretrol)
• Advantages:
• dilute drug to specific
volume appropriate for the
dose (maximum volume
150mL in the mixing
chamber)
• Y-in the dose close to
patient and/or use
microbore tubing
• Disadvantages:
• dose may have to flow
through up to 20 mL
of tubing
• small volume doses
given at slow infusion
rates will have delayed
delivery
Minibags or Bottles
• Advantages:
• convenient to dilute the dose in a prefilled
IV bag
• available in standard sizes 25 mL, 50 mL,
100 mL of D5W or Normal saline
Disadvantages of Minibags or
Bottles
• may contain more fluid than pt. can tolerate
• fixed dilution may provide inappropriate
final drug concentration
• inaccurate dose delivery due to
manufacturer’s overfill unless entire bag is
given (25mL bag contains 27-33mL or a
24% volume difference)
Disadvantages of Minibags or Bottles
• IV set used to administer the dose may retain
up to 7mL of fluid (23% of dose in 25mL bag).
This could be flushed into the patient using
additional fluid or discarded with a set change
or given at the start of the next dose after
possible drug degradation.
• if attached to primary infusion line, the extra
fluid volume causes additional delay in drug
reaching the patient
Syringes for
Manual IV Injection
Advantage:
• can inject very small volumes into tubing at
injection site near pt.
• administration rate controlled by primary IV
solution flow rate.
Syringes Manual IV Injection
Disadvantages
• time for drug delivery depends on drug
volume and flow rate of primary IV solution
• amount of drug delivered depends on
amount lost to dead space at the injection
site
• requires microbore tubing to decrease
delays in delivery
• more labour intensive – requires flush
Syringe Pumps
Advantages
• prepare drug in syringe at required dilution
and give via microbore tubing at connection
close to patient (reduced fluid volume)
• dose given accurately at a rate independent
of primary IV solution
• used for both intermittent and continuous
therapy
Syringe Pumps
Disadvantages
• only for small volumes < 50mL
• tubing will retain part of the dose
• initial capital investment required
TDM Implications of Factors Influencing IV
Drug Delivery
• Actual time for dose delivery may be longer
than the predicted time due to increases in the
distance between the drug injection site and
the patient, the total volume to be infused, the
specific gravity of the drug, or a slow IV flow
rate.
• Dose and dose timing errors may occur due to
dead space volume errors.
Total Volume Infused and Injection Site
• Volume = Dose + Fluid in tubing + Flush
(Y-site closest to patient = smallest volume,
Y-site above Buretrol = largest volume)
• Injection site: to ensure 30 minute drug
delivery in pediatric patients, inject IV
manually or infuse IV using a syringe
pump with microbore tubing at Y-site of IV
set closest to patient
Time for Delivery of Chloramphenicol Using
Buretrol IV Set with TubingVolume 18 mL
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IV Rate
(mL/hr)
Drug volume
(mL)
5
10
Time to
Delivery 95%
of dose (min)
Predict. Actual
336
>360
15
10
112
270
29
10
58
150
Predicted time of
chloramphenicol delivery with a
Buretrol set
• Predicted time to delivery of drug dose
(minutes)
• = Med. volume + volume of set x 60min
IV Rate (mL\hour)
i.e.. 10 mL + 18 mL x 60min = 336 minutes
5 mL/hr
Time for Drug Delivery Via Buretrol
IV Set
• Delivery of a drug added to a Buretrol is
affected by slow IV flow rates and too small IV
flush volumes.
• Medication does not flow toward the patient
like a plug, pushing the maintenance IV fluid
into the patient without mixing.
• Viscosity and specific gravity of medications
and maintenance IV fluids vary so mixing will
occur within the IV tubing
• The amount of mixing depends on the
diameter of the IV tubing and IV flow rate
• When using a Buretrol set, increase IV flow
rate and flush volume to compensate for the
mixing occurring within the IV tubing
• Use a flush volume equal to approximately
1.5 to 2 times the volume of the IV set from
the bottom of the Buretrol to the patient
• Administer dose plus flushes over required
dose administration time
• QUESTION: A 2 kg, 1 month old, neonate
is receiving Digoxin 1.5mcg/kg/dose IV
q12h. The physician wishes to increase the
dose by 10%.
• Is the commercial preparation available in a
suitable concentration to allow accurate
measurement of a 10% change in the dose?
• Which drug delivery devices may be used?
• What are sources of error in dose delivery
& what effect may this have on the reported
Digoxin level?
Solution
• Digoxin dose and proposed dose change
are appropriate
• Digoxin is available as 50mcg/mL Inj
• Cannot measure a 10% dose change with
the commercially available product
• Dilute Digoxin with NS to 10mcg/mL so
10% dose change is measurable
• Device - 1cc syringe, manual IV injection
into Y-site nearest to patient
• Sources of error: syringe dead space
volume (0.05mL) and low IV flow rate
(1-10ml\hr in neonate)
• 3.3mcg dose = 0.33 mL of 10 mcg/mL
• 0.05mL x 10 mcg/mL= 0.5mcg (dead space
volume is 15% of dose )
• Digoxin level either 15% higher or lower
than predicted if measuring inaccurate.
Inappropriate timing of Digoxin levels and
uninterpretable results if drug delivery
delayed.
References
• 1. Comprehensive Pediatric Nursing. New York:
McGraw-Hill; 1986: Appendix 1.
• 2. Leff RD, Roberts RJ.Principles and techniques of
IV administration. In Practical aspects of intravenous
drug administration.ASHP 1992(2):4-41.
• 3. Nahata M. Methods of intravenous drug infusion in
pediatric patients. The Am J Intravenous Therapy &
Clin N 1984: May: 6-7.
• 4. Hunt, Max L. Training Manual for Intravenous
Admixture Personnel Fifth Edition.Baxter
Healthcare Corporation & Precept Press, USA,
1995.
• 5. Roberts RJ. Intravenous administration of
medication in pediatric patients: problems and
solutions. Ped Clin N Amer 1981; 28:23-34.
• 6. The Hospital for Sick Children. Policies and
Drug Information for Nurses Manual. Parenteral
therapy - not intravenous. Toronto; 2000:4.014.03.
• 7. Rice, Stephen P., A Review of Parenteral
Admixtures Requiring Select Containers and
Administration Sets, International Journal of
Pharmaceutical Compounding, Vol 6, No 2,
March\April 2002.
• 8. Turco, Salvatore J. , Editor. The Sourcebook
for IV Therapy IVAC Corporation, San Diego, Ca,
1985.
• 9. http://www.hc-sc.gc.ca/hpbdgps/therapeut/zfiles/english/advcomm/eap/deh
p/eap-dehp-final-report-2002-jan-11_e.html
Health Canada Expert Advisory Panel On DEHP
In Medical Devices, Final Report 220 January 11,
Health Canada, 2002.
• 10. http://www.fda.gov/cdrh/ost/dehp-pvc.pdf
Safety Assessment of Di(2-ethylhexyl)phthalate
(DEHP) Released from PVC Medical Devices
Centre for Devices and Radiological Health, U.S.
Food and Drug Administration, Rockville, MD,
2001.