pediatric drug calculations 03
TRANSCRIPT
•Drug dosages differ greatly from adults because of physiologic differences
•Neonates and infants have immature kidney and liver function-delays metabolism and elimination of many drugs
•Decreases drug absorption- neonates have delayed gastric emptying, children younger than 3 years old has decreased gastric secretions
•Have lower concentration of plasma proteins – can cause toxicity with highly protein bound drugs
•Young children have less total body fat and more body water
•All injections must be given in a manner that minimizes physical and psychosocial trauma
Fried’s Rule
•applies to children younger than 1 year of age
Child’s dose (age <1 yr) = infant’s age (in months) x average adult dose150 months
Young’s Rule
• for children 1 to 12 years of age
Child’s dose (1- 12 yrs) = child’s age (in years) x average adult dose Child’s age (in yrs) + 12
Clark’s Rule
•uses the child’s weight to calculate and assumes that the adult dose is based on a 150 lb person
Child’s dose =weight of child ( in pounds) x average adult dose 150
Paediatric Guidelines for IM injections According to Muscle Group
Amount by Muscle Group (ml)
AGE Vastus lateralis
Gluteus Maximus
Ventrogluteal Deltoid
Birth to 4months
0.5-1 Not safe 0.5-1 Not safe
Infants 0.5-1 Not safe 1 Not safe
Toodlers 0.5-2 0.5-1 0.5-1 0.5-1
Preschool and older children
2 0.5-2 2-3 0.5-1
Adolescents 2 2 2-5 1-1.5
LIFE SPAN CONSIDERATIONS
•Beginning to end of life –body changes in many ways
•Changes that have an effect on the four phases of drug action
Drug Therapy during Pregnancy•A fetus is exposed to many of the same
substances as the mother, including any drugs that she takes.
•First trimester – period of greatest danger of drug induced developmental defects.
•The FDA classifies drugs according to their safety for use during pregnancy
FDA Pregnancy Categories•Category A – no risk to fetus•Category B – little or no risk•Category C – animal studies shows risk to
fetus•Category D – risk to human fetus has
been proven; may be used in life-threatening conditions
•Category X – avoid during pregnancy due to proven risk to human fetu
Neonatal and Pediatric PatientsCLASSIFIACTION OF YOUNG PATIENTS
AGE RANGE CLASSIFICATION
Younger than 38 week gestation Premature or preterm infant
Younger than 1 month Neonate or newborn infant
1 month to younger than 1 year Infant
1 year to younger the 12 y/o child
Absorption•Gastric ph is less acidic because acid-
producing cells in the stomach are immature until approximately 1-2 years of age.
•Gastric emptying is slowed because of slow or irregular peristalsis
• First pass elimination by the liver is reduced because of the immaturity of the liver and reduced level of microsomal enzymes
• Intramuscular absorption is faster and irregular
Distribution
•Total body water is 70% to 80% in full term infants, 85% in premature NBs, 64% in children 1-2 years
•Fat content is lower in young patients because of greater total body water
•Protein binding is decreased •More drugs enter the brain because of
immature blood brain barrier
Metabolism
•Levels of microsomal enzymes are metabolism because the immature liver has not yet producing enough
•Older children may have increased and require higher dosages once hepatic enzymes are produced
Excretion
•GFR and tubular secretion and reabsorption are all decreased in young patients because of kidney immaturity
•Perfusion to the kidneys may be decreased and result in reduced renal function, concentrating ability, and excretion of drugs
NB : Strictly follow the guidelines for Pediatric dosage calculations
The Elderly PatientsPHYSIOLOGIC CHANGES
SYSTEM PHYSIOLOGIC CHANGE
Cardiovascular Dec. CO = Dec. Absorption and Dist. Dec. Blood flow=Dec. Absorption and
Dist.
Gastrointestinal Increased PH = altered absorptionDecreased peristalsis =dec. Gastric
emptying
Hepatic Decreased enzyme and blood flow =decreased metabolism
Renal Decreased blood flow, function, and GFR =dec. excretion
Absorption•Gastric PH is less acidic because of gradual
reduction in the production of HCL acid in the stomach
•Gastric emptying is slowed because of a decline in smooth muscle tone and motor activity
•Movement throughout the GIT is slower• Blood flow to the GIT is reduced by 40%-
decreased CO and Perfusion• Absorptive surface area is decreased because
the aging process blunts and flattens villi
Distribution
•40 to 60 y/o, total body water is 55% in males, 47% in females, over 60 y/o, total body water 52% in male, 46 in females
•Fat content is increased because of decreased lean body mass
•Protein binding sites are reduced because of decreased production of proteins by the aging liver and reduced protein intake
Metabolism
•The levels of microsomal enzymes are decreased because the capacity of the aging liver to produce them is reduced
•Liver blood flow is reduced by approximately 1.5% per year after 25 years of age, which decreases hepatic metabolism
Excretion
•GFR is decreased by 40% to 50% primarily because of decrease blood flow
•The number of intact nephrons is decreased
Medication error• defined as any preventable event that may cause
or lead to inappropriate medication use or patient harm, while the medication is in the control of the health care professional, patient, or consumer.
• Such events may be related to professional practice, health care products, procedures, and systems including: prescribing; order communication; product labeling, packaging, and nomenclature; compounding; dispensing; distribution; administration; education; monitoring; and use.
Types of Medication Errors
Common types of medication errors include:• Administering the wrong dosage• Prescribing the wrong dosage• Prescribing the wrong medication all together• Prescribing medication that cannot safely be mixed with
other medications the patient is currently taking• Failing to check a patient’s medical history to determine
whether or not the patient can safely consume the drug• Dispensing the wrong medication• Including the wrong dosage instructions on the prescription
bottle
Contributing factors• Miscommunication• Look-alike medication names• Confusion of generic and brand namesMajor causes of error:▫Distractions and interruptions during
administration▫ Illegible written orders▫ Incorrect dosage calculations▫Similar drug names and packaging
Examples of Errors• Prescribing: Illegible handwriting or unclear orders• Non-compliance with order-writing guidelines• Wrong order form used• Therapeutically incorrect orders• Decimal point errors• Documenting -Improper therapeutic screening of order at
time of taking• order off by nursing or pharmacy (dose, allergy check)• Incorrect/incomplete transcription of order on MAR or
Kardex• Not transcribed onto MAR or Kardex• Pharmacy transcription error• Incorrect documentation of medication administered
• Incorrectly dispensed/reconstituted/labeled by pharmacy• Incorrectly diluted/reconstituted/labeled by nursing• Administration -Misread orders/MAR/Kardex/label• Forgot to give• Incorrect pump setting/drip rate• Gave to wrong patient• Incorrect dose calculation• Incorrect administration• Equipment/device/tubing problem (e.g., tubing
disconnects, tubing• clamped)• Monitoring -Improper monitoring of drug effect (e.g.,
narcotic administered to patient with low RR
Reporting and Responding to Medication Errors•Checking the patient by assessing all
relevant parameters and documenting accordingly
•Assessing patient for effects of the drugs and consulting reference materials and colleagues as needed.
•Performing medication reconciliation to verify all of the patient’s correct medications at each point of care
•Regularly asking the patient to verify his or her identity and date of birth
•Completing ME reporting forms after contacting the health care team.
•Monitoring the progress of patient’s condition regularly
•Thinking and acting critically and modifying nursing practice to prevent further errors
Medication Reconciliation
•A procedure that seeks to prevent medication errors through the ongoing assessment and updating of every patients’ list of medications throughout the health care process and the timely communication of such information to both patients and health care team.
• Involves three steps
1. VERIFICATI ON- Collection of patient’s medication
information with a focus on medications currently used ( Prescription and OTC)
2. Clarification- Professional review of this information to
ensure that medications and dosages are appropriate for the patient
3. RECONCILIATION- Further investigation of any discrepancies
and documentation of relevant communications and changes in medication orders.
To ensure ongoing accuracy of medication use, these steps should be repeated at each stage of health care delivery:1. Admission2. Status Change ( Critical to stable)3. Patient Transfer4. Discharge
Nursing Measures to Prevent Medication Errors•Minimize the use of verbal and telephone
orders•List the indication next to drug order on
the medication record•Avoid use abbreviations, medical
shorthand, and acronyms•Never assume anything about any drug
order or prescription including route
• If a medication order is questioned for any reason, never assume that the prescriber is always correct. Always act as patients’ advocate.
•Do not try to decipher illegibly written orders
• If in doubt of the correctness of the order, double check with the prescriber
•Compare the medication order against what is on hand
•Never use trailing zeros
Other measures....
•Carefully read all labels for accuracy, expiration dates, and dilution requirements
•Be familiar with techniques of administration
•Encourage the use of both trade and generic name in drug orders
•Always double check a medication product’s labeling
•Always verify new medication administration records if they have been rewritten or re entered for any reason
Client Education for Medication Usage
• Find out what drug you're taking and what it's for. Rather than simply letting the doctor write you a prescription and send you on your way, be sure to ask the name of the drug.
• Find out how to take the drug and make sure you understand the directions
• Keep a list of all medications, including OTC drugs, as well as dietary supplements, medicinal herbs, and other substances you take for health reasons, and report it to your health care providers.