Paeds Flashcards
Estimate weight formula
Weight can be estimated using the formula:
2 × (age + 4), or
(3 × age) + 7
Dose adrenaline i arrest
For paediatric cardiac arrest the dose of adrenaline is
10 micrograms per kilogram
0.1 ml/kg of 1 in 10,000 solution
via the intravenous or intraosseous routes
Pyloric stenosis
typical presentation
electrolyte abnormality
kidney response
ongenital pyloric stenosis usually presents in male infants in the first two months of life.
The electrolyte abnormality is characteristically hypochloraemic alkalosis (not hyperchloraemic), due to the loss of chloride and hydrogen ions during vomiting.
Kidney response initially in pyloric stenosis
The initial response by the kidneys is to excrete alkaline urine (not acid),
which also contains sodium and potassium ions.
Conservation of water, sodium and chloride ions causes the kidneys to excrete potassium and hydrogen ions in exchange for sodium ions.
The acidic urine exacerbates the alkalaemia resulting in hypokalaemia.
When to perform pyloromyotomy in
Performing a pyloromyotomy is not a surgical emergency, and it should be delayed until the infant has been fluid resuscitated and the biochemical profile normalised.
Acceptable plasma electrolyte values are: in pyloric stenosis
Chloride ions >90 mmol/L
Sodium ions >135 mmol/L, and
Bicarbonate ions < 25 mmol/L.
Postoperative apnoea and hypoventilation may occur if surgery is performed before correction of the biochemical abnormality, and is due to an alkaline cerebrospinal fluid.
Fluid of choice for resus in Pyloric stenosis
why
Normal saline is the fluid of choice as it is a hydrogen ion donor and does not contribute to the bicarbonate load.
Hartmann’s solution should be avoided in patients with metabolic alkalosis.
Estimated blood volume calculation
The blood volume calculation is based on 80 ml/kg up to 2 years of age and 70 ml/kg thereafter.
The injured girl therefore has an estimated blood volume of 1120 ml or approximately 1200 ml.
In children older than one year the following formula is used to calculate the internal diameter of an appropriate endotracheal tube:
internal diameter = (age/4) + 4
The systolic blood pressure in a child can be calculated using:
systolic blood pressure = (age in years × 2) + 80.
Hypotension as a sign
Hypotension is often a late sign in hypovolaemic children,
as the blood pressure is well maintained and only falls when the heart rate reaches the maximum.
More than 25% of the blood volume may be lost before hypotension occurs,
which is >300 ml for our injured girl.
Large volumes of blood can be lost from paediatric scalp wounds and may represent a significant proportion of the child’s blood volume. Nevertheless, the child should be examined to exclude occult injuries in the head, chest or abdomen.
Apgar
0 1 2 Appearance Pale or blue Pink body, blue extremities Pink body and extremities
Pulse Absent <100 BPM ≥100 BPM
Grimace Absent Grimace or noticeable body movement Coughs, sneezes or pulls away
Activity Absent Some flexion of extremities Active and spontaneous movement of limbs
Respiration Absent Slow and irregular Good breathing with crying
APLS status epilepticus protocol recommends
that in a child with IV access the most appropriate treatment for status epilepticus is a benzodiazepine IV (lorazepam, midazolam or diazepam), up to 2 doses at 5 minute intervals. If after a further 5 minutes, seizures are still continuing then the next step is to give either phenytoin or phenobaritone IV. RSI with thiopentone is the final step.
Status epilepticus is defined
as an active part of a tonic-clonic seizure lasting 5 minutes or longer without recovering consciousness from the first one
Detailed steps in Status Epilepticus
Step 1 (Five minutes after start of seizures):
Many children may have already undergone step 1 before arrival at hospital and it is important to remember this. If intravascular access is available then initial treatment is lorazepam 0.1 mg/kg IV If no intravascular access then give buccal midazolam 0.5 mg/kg or rectal diazepam 0.5 mg/kg. Step 2 (Ten minutes after start of seizure):
If the convulsions continue give a second dose of benzodiazepine, call for senior help and start to prepare phenytoin No more than two doses or benzodiazepines should be given (including any doses given before arrival at hospital) If still no IV access then obtain intraosseous access (IO). Step 3 (Ten minutes after step 2)
Senior help along with anaesthetic/ICU help should be sought
Phenytoin 20 mg/kg IV over 20 minutes
If the seizure stops before the full dose of phenytoin is given then the infusion should be completed as this provides up to 24 hours of anticonvulsant effect
In children already receiving phenytoin as treatment for epilepsy then an alternative is phenobarbitone 20 mg/kg IV over five minutes
Once the phenytoin is started, senior staff may wish to give rectal paraldehyde 0.4 mg/kg although this is no longer incuded in the routine algorithm recommended by APLS.
Step 4 (20 minutes after step 3)
If 20 minutes after starting phenytoin the child remains in status epilepticus then rapid sequence induction of anaestheisa with thiopentone and a short acting paralysing agent is needed and the child transferred to paediatric intensive care.
narrowest part of the upper airway is
the cricoid ring.
FEV/FVC as age
FEV1/FVC ratio decreases progressively from childhood to old age. Small children have larger middle and peripheral airway sizes than are obtained from the proportional downscaling of the adult lung, and lung volumes increase more rapidly than airway calibre in early life.
