Acidic and highly protein bound drugs
a bilirubin induced brain dysfunction
Basic medications such as alfentanil, lidocaine, diphenhydramine, and atropine typically bind to
plasma alpha-1 acid glycoprotein
Preterm and term infants have a greater proportion of body weight in the form of water than in older children, so
The net effect on water-soluble medications is a greater Vd in infants--> the loading dose will increase
Examples of water soluble drugs
- some antibiotics
intracellular fluid compartments ___________ with age
extracellular fluid compartments _________ with increasing age
Phase 1 metabolic reactions
- oxidation, reduction, hydrolysis
- CP450 reactions
- makes drugs more polar
Phase 2 metabolic reactions
glucuronidation, sulfation, acetylation
Increases the hydrophilicity of molecules to facilitate renal excretion
Morphine sulfate, Tylenol, and lorazepam undergo _________ metabolism
Phase 2- glucuronidation
What is used to treat apnea and bradycardia in infants, and what drug category are they in?
1. Caffeine and Theophylline
In terms of renal excretion, what can be expected in premature babies?
- Immature glomerular filtration and tubular function means less drug is filtered out, creating a situation in which toxicity is easily possible.
- Glomerular filtration and tubular function are mature by 20 weeks.
First order kinetics
- A constant fraction of drug is removed per unit of time.
- Half-life is important here
Zero Order Kinetics
A constant amount of drug is eliminated per unit of time
Caffeine, aspirin, diazepam, furosemide, indomethacin, phenytoin, cholramphenicol
- Lethal dose in 50% of animals
- Significantly lower in newborn animals than adult animals
All inhalation anesthetics are ether and based on:
- methyl ethyl and
- methyl isopropyl
Which of the ethyl agents are stereoisomers?
isoflurane and enflurane
The chloride atom is closer to the ester bridge in isoflurane than enflurane
Does changing from isoflurane to desflurane at the end of the case improve wake-up time?
No. Isoflurane and desflurane are so much alike, that changing to desflurance will increase the time needed for iso to come out of the tissues
What are the 6 factors that determine uptake of the inhalational anesthetics?
- 1. Inspired concentration (overpressurization)
- 2. Alveolar ventilation (increased flow and rate)
- 3. Functional residual capacity
- 4. Cardiac Output
- 5. Solubility
- 6. Alveolar to venous partial pressure gradient
Define functional residual capacity
- is the volume of air present in the lungs,
- specifically the parenchyma tissues, at the end of passive expiration.
Inspired concentration increases works best on what type of agents?
More soluble. Because the gas leaves the alveoli and enters the blood to be distributed in tissues faster. Remember, alveolar concentration reflects brain and spinal cord concentration
What is the primary determinant of the rate of the delivery to the anesthetic to the lungs?
The ratio of alveolar ventilation to functional residual capacity
What are the B:G values for the following gases?
- 1. 0.47
- 2. 0.42
- 3. 0.6
- 4. 1.4
- 5. 2.5
Herring breuer reflex
If the alveoli are overventilated and stretched, baroreceptor activation will occur and vagal response will slow down the heart rate
Brevital IV dose
1-2 mg/kg IV
Brevital rectal dose
- without pre-op 5-6 mg/kg
- additional dosing 0.5-2mg/kg
- Max dose= 10mg/kg total
- 2.8-3 mg/kg without pre-op meds
- 5.4 mg/kg for LMA insertion
- 1-3 mg/kg IV
- 5-10 mg/kg IM
- Redose with 0.5 to 1 mg/kg
- Outside OR 0.25 to 0.5 mg/kg IV or 1-2 mg/kg IM
IV 0.1- 0.2 mg/kg
- IV 0.5-1 mcg/kg
- 0.25-0.5 mcg/kg/min infusion
- 0.2-0.3 mg/kg PO or PR
- 0.1 - 0.2 mg/kg IV
0.05-0.15 mg/kg IV
0.1 - 0.2 mg/kg IM
20-75mg po or PR
Risk factors for Retinopathy of Prematurity
maternal diabetes, exogenous bright light , maternal antihistamine use within 2 weeks of delivery
IN addition to brevital, which drugs can also help to induce seizures?
Caffiene and theophylline
Factors affecting fentanyl clearance include:
hepatic blood flow, hepatic function, age dependent changes in Vd
Low dose fentanyl-
termination of action is dependent on redistribution and liver clearance
High dose fentanyl-
accumulates in muscle and fat, may see prolonged respiratory depression
The ___ ion is the primary extracellular solute
The _____ ion is the primary intracellular solute
Primarily regulated by ADH, thirst, and renal concentrating ability
ADH is released when:
serum osmolality reaches a threshold of 280 mOsm. Threshold is decreased with hypovolemia and hypotension
Stimulated by decreased arterial blood pressure. Renin released by juxtaglomerular cells in glomerulus
What are the three severe congenital defects that always indicate a difficult airway?
- Pierre Robin
- Treacher Collins
When do the frontal sinus's develop?
2-6 years of age
When do the ethmoidal, shpenoidal, and maxillary sinuses develop?
after 6 years of age
Low birth weight
infant weighing less than 2500 grams
Very low birth weight
infant weighing less than 1500 grams
Extremely low birth weight
infant weighing less than 1000 grams
Infant weighing less than 750 grams
infant is born before 37 weeks
infant born between 37 and 42 weeks
Post term means
Infant born after 42 weeks
an infant that weighs less than 2500 grams at birth, regardless of gestational age
an increase in physical size
an increase in complexity and function
What is the best indicator of growth?
What is the most sensitive indicator of well being?
The anterior fontanelle closes at
9 to 18 months of age
The posterior fontanelle closes at
about 4 months of age
premature synostosis of sutures that can result in abnormal head shape and may retard brain growth and development
What are the 3 stages of lung development?
- G- glandular
- C- canalicular
- A- alveolar
vital 24 week is in canalicular stage
Three types of attachment
- Securely attached
- Anxiously attached
- Insecurely attached
Three dimensions that infants temperament are classified as:
Components of informed consent
- Decision making ability
The two parameters that place patients at most risk of aspiration pneumonitis are:
- gastric fluid volume > 0.4ml/kg and
- pH < 2.5
Emergence delirium incidence is highly correlated with:
doctrine of parens patriae
The state has an obligation to intervene to protect the interests of incompetent patients
i.e. Jehovah's Witness and blood products in children
Alkalotic and acidic or neutral drugs will bind readily with it.