prepared by dr. mahmoud abdel-khalek pediatric anesthesia

Prepared byDr. Mahmoud Abdel-Khalek

Pediatric Anesthesia

Not just a small adult The principles of pre-operative assessment,

anesthetic management and post-operative care described for adults apply equally well to the pediatric patient

Specific variations in management of the pediatric patient result from differences in anatomy and physiology in this patient population, as compared to adult patients. Some of these differences are discussed briefly hereinafter

Respiratory system The occiput is relatively prominent in infants and

young children. This means that the “sniffing position” is often best achieved with the head in the neutral position, without the use of a pillow.

The relatively large tongue may hinder visualization of the larynx or contribute to upper airway obstruction under anesthesia.

The epiglottis is long, angled and mobile. Because of this, a Magill blade is often used (in infants and young children) to lift the epiglottis directly to expose the larynx.

The larynx itself is positioned higher (C4 vs. C6 in adult) and more anteriorly.

Respiratory system The narrowest part of the pediatric airway is the

subglottic region, at the level of the cricoid cartilage. Therefore, the use of a cuffed endotracheal tube (ETT) in a child less than 8 years of age is unnecessary and undesirable, as the narrow subglottic region provides its own seal.

Because the trachea is narrowed, short and easily traumatized, appropriate selection of an ETT is critical.

Recommended sizes of ETT by age can be estimated using the formula age/4+ 4

Respiratory system

Respiratory system The pediatric airway is relatively more prone to

obstruction than the adult airway. Infants are obligate nose breathers and the nares

are small and easily obstructed by edema or mucous.

Due to subglottic narrowing, a small amount of edema resulting from ETT trauma or pre-existing infection (trachiitis or croup) can seriously compromise airway patency.

Finally, laryngospasm is common in children. In order to avoid laryngospasm, pediatric patients

are extubated either at a deep plane of anesthesia or wide awake.

Respiratory system The pediatric patient is more prone to hypoxemia

than most adults. Children have smaller functional residual capacity

In addition, the pediatric patient has a markedly increased oxygen consumption which is usually maintained with an increased minute ventilation.

The result of both of these factors is that the pediatric

patient will desaturate much more rapidly during apnea.

Adequate pre-oxygenation is key to the airway management of the pediatric patient.

Respiratory system

Lung mechanics and respiratory variables in neonates

Cardiovascular system Infants and young children have a heart-rate

dependent cardiac output. This means that with bradycardia, their stiff left

ventricles are unable to increase stroke volume to maintain cardiac output.

This explains why bradycardia is undesirable in pediatric patients. Curiously, the vagus nerve is dominant and they are prone to develop bradycardia in response to certain types of noxious stimuli e.g. hypoxemia and laryngoscopy.

It is common practice, therefore, to pre-treat infants and young children with atropine just prior to the induction of anesthesia. Bradycardia in the pediatric patient must always be assumed to be a result of hypoxemia until proven otherwise.

Pediatric ABP& HR

GIT The risks of regurgitation and aspiration are lower

than adult patients. Pediatric patients are easy to become dehydrated

during a period of fasting. Thus, NPO guidelines for pediatric patients are not strict like that for adult population.

It is common practice to allow – clear fluids from 2-4-hours pre-operatively– breast milk up to 4 hours pre-operatively– formula up to 6 hours preoperatively

CNS MAC values of inhalational anesthetics are higher

in infants and children, compared to adults By 6 months to a year of age, infants can feel

anxiety in the immediate pre-operative period so pediatric patients may be pre-medicated with benzodiazepines, opioids (which may delay recovery)

In many centers a parent is allowed in the operating room for induction to avoid separation anxiety for the child.

Inhalation (“mask”) inductions are often used in order to avoid having to insert an IV in the awake child.

EMLA cream can be useful for awake insertion of IV cannula

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