Advanced Pediatrics

Question 1

3 year old child is to undergo outpatient surgery and had a recent upper respiratory infection 2 weeks ago, which is the best plan for this child:

A. Proceed so long as the child does not have thick secretions or fever
B. Proceed so long as an LMA or mask ventilation is planned
C. Proceed if the patient is not wheezing
D. All of the above are correct
E. Delay the case

Answer 1

D: All of the above are correct

Airway reactivity following a URI is increased (4-6 weeks). The incidence of laryngospasm, bronchospasm, episode of hypoxia, atelectasis, and post-intubation croup is increased in children with URIs, but this did not affect the overall outcome (children were discharged home, etc). The evidence shows that the above listed problems are greatly increased with tracheal intubation and much less with LMAs and mask ventilation. Patients with productive cough, fever, worsening symptoms, wheezing, snoring, nasal congestion, or are exposed to smokers at home are at the very highest risk.

Question 2

Which of the following is proven to decrease the incidence of adverse outcomes associated with URI:

A. Preoperative albuterol nebulization
B. Preoperative ipratropium nebulization
C. Preoperative glycopyrolate
D. Humidification of airway gasses
E. None of the above

Answer 2

E: None of the above

Each of the following have a sensible physiological grounding, but are without evidence that it has any clinical significance. One of the reasons that studying these interventions are low yield is that significant morbidity associated with URIs is unproven (see question 1). Airway reactivity has a strong parasympathetic component and anticholinergics such as answers B & C are sensible options, but have shown no benefit in this population. The same goes for attacking the sympathetic system with B2 agonism (answer A). Humidification of airway gasses help prevent drying secretions (snot) and preserving mucociliary function, but there is a lack of data supporting an actual clinical benefit.

Question 3

Just so you’ll know:
Just to clarify, although after 6 weeks airway associated complications decrease, overall morbidity does not
Should you avoid desflurane in URI?

Answer 3

Ok right , right
Desflurane (answer E) is an airway irritant, but with deep levels, airway reflexes are depressed as with all volatiles. It might make sense to avoid desflurane in URI, but there are no data to support this.

Question 4

Formula for depth and size of ETT in children

Answer 4

The formula for calculating ETT size is: 4 + (Age/4). The formulas used for estimating correct depth of the ETT are: 12 + (Age/2), Kg/5 + 12, or 3 X diameter of ETT

Question 5

Laryngospasm is due to what:

Answer 5

Laryngospasm is secondary to superior laryngeal nerve stimulation

Question 6

A 2 year old child finished a 3 hour anesthetic with a size 5.0 ETT and is making high pitched inspiratory noises in the PACU. All vital signs are normal and respiratory effort appears normal at this time. Which of the following is the BEST next step:

A. Albuterol nebulization
B. Racaemic epinephrine nebulization
C. Dexamethasone iv
D. Immediate intubation with a 4.0 ETT
E. No treatment at this time, but continue close observation

Answer 6

Racaemic epinephrine nebulization

Post-intubation croup is more common the smaller the child (and therefore airway). Other risk factors are ETTs without leaks, long procedures, frequent movement of ETT, head and neck procedures, and large fluid shifts
Dexamethasone (answer B) and upright position may be helpful prior to extubation as the time needed to treat are relatively long (both aimed at reducing swelling). Racaemic epinephrine (answer B) decreases airway swelling almost immediately by constricting exposed vasculature. Albuterol is a B2 agonist and would not help this situation. The patient is currently stable with a patent (but constricted) airway and intubation is not needed at this time. Furthermore, in most cases, the oedema is self-limited and can be effectively treated as described above. Answer E is incorrect because the noises indicate an impending danger. It is impossible to know at this time if the oedema will be so severe to limit ventilation or if it will continue to be sub-clinical.

Question 7

Epiglottis-how will it present, how to manage the airway?

Answer 7

Epiglotitis is inflammation of the epiglottis leading to complete airway obstruction. Incidence is greatly decreased now that the most common causative bacteria (H. influenza) has a vaccine administered to nearly all children in the US
Epiglotitis is an airway emergency, especially with any sign of distress. There are multiple strategies to deal with this, but all focus around a few important principles: 1) patient should be kept calm as crying can result in airway obstruction; 2) airway obstruction only gets worse, never better; 3) intubation may prove to be difficult and emergency invasive airway equipment should be present; 4) airway obstruction can occur if the epiglottis is manipulated; 5) spontaneous ventilation should be employed for intubation. The classic airway algorithm goes as follows: do not delay intubation for definitive diagnosis, call an ENT for back-up, bring patient to the OR where emergency airway equipment is available, significant sedation should be avoided, inhalational induction or awake trach are preferred, patient should be in semi-recumbent position during the inhalational induction. Some sources prefer a fiberoptic intubation under general anesthesia (following inhalational induction or alternative technique)

Question 8

What sign would you see and on which type of imaging with epiglottis?

Answer 8

X Ray, thumbprint

Question 9

What is viral croup? Signs? What sign on which imaging modality? Treatment?

Answer 9

Croup is inflammation of the larynx, trachea, and bronchi, which at the narrowest part if the airway (just below the glottis) nearly occludes air movement (steeple sign on X-ray (answer D)) and leads to stridor, hoarseness, and the barking cough. Most cases are due to parainfluenza virus; whereas RSV leads to life threatening bronchiolitis in susceptible individuals (premature, lung, heart disease). Treatment of croup is supportive with racaemic epinephrine leading to vast improvements in most cases (answer B). Cool mist (humidified air) is not effective. Steroids are very effective as well (answer C), although its effect is far from immediate. Croup rarely requires heroic measures such as tracheal intubation or tracheotomy (0.2% of cases), but is definitely not completely benign.

Question 10

A 3 year old is in respiratory distress after eating lunch at home. Auscultation of the lungs reveal diffuse wheezing on the LEFT side. Which of the following is the most likely chest X-ray (CXR) finding: Explain each one
kids and the right mainstem?
A. Hyperinflation and air trapping on the LEFT lung with mediastinal shift towards the LEFT
B. Hyperinflation and air trapping on the LEFT lung with mediastinal shift towards the RIGHT
C. Atelectasis and volume reduction of the LEFT lung with mediastinal shift towards the LEFT
D. Atelectasis and volume reduction of the LEFT lung with mediastinal shift towards the RIGHT

Answer 10

B: Hyperinflation and air trapping on the LEFT lung with mediastinal shift towards the RIGHT

To figure out this question you need to make an educated guess between TWO possible answers (answers B & C), as answers A & D are nonsensical. Aspiration of foreign bodies result in two common lung pathologies: 1) air-trapping with resultant hyperinflation distal to the foreign body (a bit more common in children) or no air flow past the foreign body with resultant atelectasis and lung volume loss (a bit more common in adults). Since this patient had diffuse wheezing (indicative of obstructive air movement), air trapping is more likely. If the lung is hyperinflated, then the mediastinum will be pushed away towards the right (answer B). If the lung is atalectatic with volume loss, the mediastinum will be pulled towards the left (answer C). Also of note, children’s right mainstem takeoff tends to be more acute than adults making the mantra of right sided aspiration less common.

Question 11

Pt had object in right main bronch, they got it out but dropped it near the glottis, and the sat keeps dropping every second. Now what?!?!?!

Answer 11

First the object can be rapidly retrieved or pushed back into the main stem by the rigid bronchoscope, or an ETT can be placed to push the object back into the main stem.

Question 12

Which of the following endotracheal tubes (ETTs) are best suited for laryngeal polyp excision using a CO2 laser:

A. Metal ETT
B. PVC (standard) ETT with metal tape
C. Red rubber ETT
D. PVC ETT

Answer 12

A: Metal ETT

This is a question about airway fire risk. CO2 laser can ignite highly flammable gases such as oxygen and nitrous oxide, therefore either a metal ETT is preferred or no ETT at all (intermittent intubation and ventilation, for example). Metal tape can also be used, but is not as reliable as a metal ETT. The red rubber ETTs have the advantage of having a less irritating reaction in the setting of a fire.

Question 13

Following an airway fire, bronchoscopic exam reveals unexpectedly mild damage. Which of the following actions of the anesthesiologist most likely explains this:

A. Water, instead of air, was used in the endotracheal tube (ETT) cuff
B. A metal instead of a PVC ETT was used
C. Dexamethasone was given preoperatively
D. The patient was NOT muscle relaxed
E. A 50/50 mix of oxygen and nitrous oxide was used

Answer 13

A: Water, instead of air, was used in the endotracheal tube (ETT) cuff

A theoretical advantage of using water instead of air in the ETT cuff is that the water will limit the heat/ fire damage from an airway fire. The thought is, when temperatures increase, the cuff will break releasing the water. Some even advocate adding methelyne blue to the water as an early indication of fire. Using a metal tube will help prevent fire, but should it occur it has no advantage in reducing the fire’s damage (answer B). Steroids can be used to treat airway oedema occurring from a fire, but does not limit the amount of damage (answer C). There is no evidence that patient movement is an early sign of airway fire (answer D). Both oxygen and nitrous are very flammable.

Question 14

During laryngeal polyp excision using a CO2 laser in a 10 year old child, you notice smoke coming from the ETT tube, what is the NEXT best step:

Answer 14

Remove the tube!

Question 15

Cobb angle:

Answer 15

Above 10 degrees, the spine appears scoliosed, but usually does not cause cardiopulmonary pathology until the angle is at least 60 degrees.

Question 16

Long term effects of scoliosis

Answer 16

Long-standing pulmonary hypertension can lead to cor pulonale.

Question 17

What is a wake up test?

Answer 17

The wake up test is a snap shot in time and only demonstrates neurologic integrity at the time of the test. Therefore damage that occurred hours prior to the test may be irreversible and damage that occurs after the test will not be monitored.

Question 18

Risks of a wake up test:

Answer 18

Wake-up tests have had major complications including unintentional extubation, dislodgement of lines and instrumentation, and finally air embolism with deep inspiration (negative venous pressures) drawing in air through the vertebral veins (answer C)

Question 19

Can osa cause right heart failure in kids?

Answer 19

This is certainly not common, but cor pulmonale does occur in children and treatment of the OSA can have dramatic effects on the natural course of the disease (unlike adults which generally make only small improvements). Laryngomalacia is probably the second best choice as the symptoms of OSA can be found in these children, but laryngomalacia is, in fact, the actual cause of the obstruction. In this question, you are told the child has OSA, and that should be accepted as the diagnosis. Laryngomalacia (answer E) is discussed below and represents a variable extrathoracic obstruction on inspiration due to incomplete maturation of the laynynx.

Question 20

Flow volume loops and how intrathoracic vs extrathoracic ones look:
Look at question #21 in this section

Answer 20

Lesions with variable obstructions that are extrathoracic have limited ability to pull air on inspiration and intrathoracic lesions have limited ability to push air out on expiration

Question 21

Which of the following IS NOT associated with difficult intubation:

A. Pierre-Robin syndrome
B. Treacher-Collins syndrome
C. Carpenter syndrome
D. Crouzon disease
E. Niemann-Pick

Answer 21

E: Niemann-Pick

The boards love to ask you about rare congenital disease that are difficult to intubate. The most commonly seen are Pierre-Robin and Treacher-Collins which both have micrognathia and cleft palate. Other conditions you might run into is Carpenter, Crouzon, Freeman-Shldon, Goldhenar, Anderson, Apert, Cri du chat, and many, many others. Neiman-Pick is a lysosomal storage disease.

Question 22

1 year old child with DiGeorge syndrome undergoing late cleft palate repair has two distinct episodes of laryngospasm following extubation. After the patient is in the PACU stabilized, which of the following blood tests would be most helpful:
and how can you remember DiGeorge syndrome?
A. Haemoglobin (Hb)
B. Potassium (K)
C. Interferon
D. Calcium (Ca)
E. Glucose

Answer 22

D: Calcium (Ca)

There are two clues that Ca is the right answer. First, DiGeorge syndrome has a very high incidence of hypoparathyroidism with hypocalcaemia; and second, hypocalcaemia can increase the incidence of laryngospasm. Tetany (involuntary contraction of muscles) is a common sign of hypocalacaemia and one that every medical student knows. So it should make sense that if facial muscles are predisposed to spasm (Chvostek sign), why shouldn’t the muscles that control the glottis? You will see this issue also come up on the boards in the setting of a thyroidectomy where the parathyroids were not spared with resultant hypocalcaemia. The other answers are pure distractors. DiGeorge is remembered by CATCH-22: Cardiac (tetralogy of Fallot), Abnormal facies, Thymic aplasia (increased infections), Cleft palate, and Hypocalcaemia, due to a deletion on chromosome 22.

Question 23

An otherwise healthy 6 month old child is to undergo surgery for craniosynostosis in the supine position with Mayfield head support. Physical exam and head CT show no evidence of high intercranial pressure (ICP). The anesthetic plan is induction with propofol, lidocaine, fentanyl, and succinylcholine followed by propofol and remifentanyl infusion. Which of the following is the greatest anesthetic concern for this patient:

A. Bleeding
B. Venous air embolism (VAE)
C. Brain herniation
D. Malignant hyperthermia (MH)
E. Propofol infusion syndrome (PRIS)

Answer 23

The correct answer is: A: Bleeding

Craniostenosis (premature fusion of skull sutures) surgery involves dividing the skull along the suture lines, just above the cerebral venous sinuses, which can bleed quickly and profusely (answer A). These structures are typically avoided with routine intracranial surgery. VAE (answer B) can occur with open venous sinuses as they are tented open, but in the supine position where venous pressure is nearly always higher than atmospheric pressure it is less of a concern (see Neurosurgery questions 21 & 22 for more on VAE). Brain herniation should not occur with normal ICP (answer C). MH (answer D) is increased in children (although especially rare under 1 years of age), but still rare altogether. PRIS (answer E) is more likely to occur with much longer propofol infusions (48 hours +) and is described in detail in Neonatology question 27.

Question 24

What is a landmark for caudal anesthesia? Walk me through it:

Answer 24

22 to 20 gauge angiocath is positioned at the sacral hiatus (at 45 degrees) until the sacrococcygeal membrane is penetrated, then the needle angle is dropped and advanced into the epidural space. Aspiration should be negative for CSF or blood. Epinepherine should be added as an additional monitor for intravascular injection.

Question 25

which of the following doses of 0.25% bupivacaine with epinephrine is the minimum dose administered to cover post-operative pain for perineal surgery

A. 0.05 ml/ kg
B. 0.1 ml/ kg
C. 0.5 ml/ Kg
D. 1 ml/ kg
E. 2 ml/ kg

Answer 25

The correct answer is: C: 0.5 ml/ Kg

O.5 cc/kg of a dose of bupivicine greater than 0.175% will cover perineal surgery pain. Upper abdominal surgery can be covered with 1.25 ml/ Kg dose.

Question 26

What is the dose of preservative free morphine epidural doses should be administered to a child for post-operative pain:

Answer 26

0.1 mg/kg

Question 27

2 year old child received caudal anesthesia with 15 ml of 0.5% ropivicaine under general anesthesia just prior to a 15 minute inguinal hernia repair. At the end of the case, the patient is found to be completely apneic even though no opioids were administered and the end tidal sevoflurane concentration is 0.01%. What is the most likely cause:
Explain why each one is right or wrong:

A. The angiocath penetrated the spinal cord
B. The angiocath penetrated the dural sac
C. The angiocath punctured the sacrococcygeal membrane
D. The patient has an epidural haematoma
E. Intravascular injection of ropivicaine

Answer 27

B: The angiocath penetrated the dural sac

The patient has a high spinal from dural puncture. Just like in adults large volumes of local anesthetics can lead to respiratory collapse. Also, just like adults, dural puncture can lead to post-dural puncture headaches, although probably less frequently in children. Epirdural blood patches can be used for children and adults for this complication. Damage of spinal elements (answer A) is very rare with caudal approach, and presents with nerve distribution specific injuries (not apnea). The puncture of the sacrococcygeal membrane is the distinct pop felt when placing a caudal anesthetic properly (answer C). An epidural haematoma would more likely result in bladder/ bowel dysfunction and sensory/ motor loss of the lower extremities (answer D). Intravascular injection of ropivicaine or bupivacaine can lead to bradycardia, heart block, and cardiovascular collapse unresponsive to epinephrine, defibrillation, and chest compressions. Intralipid is given in this situation to bind ropivicaine (answer E).

Question 28

Which of the following has a positive correlation with malignant hyperthermia:

A. Duchenne’s muscular dystrophy (DMD)
B. Ataxia telangiectasia (AT)
C. Treacher-Collins syndrome (TCS)
D. Central-core disease (CCD)
E. Osteogenesis imperfect (OI)

Answer 28

D: Central-core disease (CCD)

If you saw three right answers (answers A, D, & E), you have mastered the information of review books, which are superficial in knowledge and out dated despite recent publication dates. DMD does not have an increased rate of MH, as compared to the general population (see Neurosurgery question 29). MH-like reactions involve muscle breakdown causing rhabdomyolysis, hyperthermia, and hyperkalaemia in response to volatile agents. Hyperkalaemic cardiac arrest can occur at any point in the anesthetic (earliest being 10 minutes after induction, latest 20 minutes after surgery). OI have a high mortality rate with fragile, easily broken bones (answer E) and is NOT associated with MH despite what some certain review books say. CCD does have a MH susceptibility (answer D). CCD involves muscle dystrophy without muscle wasting. TCS (answer C) is a classic difficult to intubate condition (along with Pierre-Robin) but has no association with MH. AT is associated with cerebellar ataxia, skin and conjuctival telangiectasia, and immune deficiency, but not MH (answer B).

Question 29

Triggering agents for MH:

Answer 29

Triggering agents are halogenated volatiles and succinylcholine

Question 30

Pathophys behind MH

Answer 30

Abnormalities in calcium induced release of calcium (CIRC)

CIRC is the MH buzzword I think you will have to know for the boards (also described as ECRC = excitation calcium release coupling). Multiple genes have been identified leading to MH, with many of them involving the ryanodine receptor. Normally, extra-cellular calcium enters the myocyte through the dihydropyrodine receptors on the T-tubule, which is adjacent to the SR. The calcium from the dihydropyrodine receptors open the ryanodine receptor, allowing a very large calcium release from the SR, resulting in muscle contraction. In MH, the ryanodine receptor is essentially stuck in the open position where calcium is continually released and leads to contraction (see Cardiology Physiology question 3 for description of contraction). This unopposed contraction (hyperthermia, oxygen consumption, increased CO2 production) leads to ATP depletion, and muscle breakdown (thus rhabdomyolysis, hyperkalaemia, increased creatinine kinase). Therefore the abnormal CIRC signaling underlies the pathology.

Question 31

MH ABG:

Answer 31

MH is associated with a mixed respiratory (increased CO2 production) and metabolic (increased O2 consumption, lactic acid production) acidoses.

Question 32

A patient with full-blown malignant hyperthermia (MH) would most likely have which of the following laboratory values:

A. Hyperphosphataemia
B. Decreased creatine kinase
C. Haemoglobinuria
D. Hypokalaemia
E. Thrombocytopaenia

Answer 32

E: Thrombocytopaenia

Of the above choices, thrombocytopaenia would be most likely. MH leads to increased oxygen consumption and CO2 production leading to a mixed respiratory and metabolic acidosis. With myocyte death, potassium, creatine kinase and myoglobin are released leading to hyperkalaemia, increased creatinine kinase (answer B), and myoglobinuria (not answer C, haemoglobinuria). Hyponatraemia is commomly seen in MH, not hypokalaemia (answer D). Tissue thromboplastin release leads to disseminated intravascular coagulation (DIC) with resultant thrombocytopaenia (answer E). See Haematology questions 9 & 10 for more detail on DIC. Increased creatine kinase and myoglobin are essentially universally seen with MH, but neither are very specific.

Question 33

Why is rocuronium NOT effective in malignant hyperthermia?

Answer 33

Acetycholine signals do not result in action potentials under blockade, therefore voltage gated calcium channels do not open, and calcium induced release of calcium (CIRC) does not occur (resulting in sarcoplasmic release of calcium and muscle contraction). However, in MH, the muscle endplate is circumvented as CIRC continues without any input from neuron signaling. Therefore, MH is unaffected by muscle relaxants

Question 34

The halothane-caffeine contracture test (HCCT) is:

A. Is a highly sensitive test for MH
B. Is a highly specific test for MH

Answer 34

A: Is a highly sensitive test for MH

HCCT is highly sensitive, as most people susceptible to MH will have a positive test. However, it is not very specific, in that many of the people who test positive on the HCCT do not have MH. HCCT remains a more sensitive test as compared to genetic testing (of the ryanodine alleles).

Question 35

What do thiopental and pancuronium have to do with MH?

Answer 35

Raise the triggering threshold for MH

Both thiopental and pancurionium appear to be mildly protective in that they may increase the triggering threshold for MH.

Question 36

NMS-what causes it? How can you treat it? Do muscle relaxants work?

Answer 36

Both MH and NMS can be treated with dantrolene. Bromocriptine and amantadine will only work with NMS. NMS (answer E) is the only one other than MH to have associated rigidity (which is the one of the most specific signs for MH) and is due to withdrawal* of neuroleptic medicines (more specifically, depletion of dopamine in the basal ganglia leading to rigidity…sound familiar: Parkinsons). Unlike MH, NMS’s rigidity responds to muscle relaxation and succinylcholine is not contraindicated. Although textbooks love to give a MH differential, only NMS closely resembles MH.

Question 37

Steps to take for patients with MH
Which of the following is NOT part of preparing an anesthesia machine for a malignant hyperthermia (MH) patient:

A. Taping the sevoflurane vaporizer to the OFF position
B. Flushing the machine with 10 L/ min oxygen for 20 minutes
C. Replacing fresh outlet gas hose
D. Replacing the CO2 absorbent and canister
E. Replacing the circle system circuit

Answer 37

Taping the sevoflurane vaporizer to the OFF position

Halogenated volatile agents must be physically removed from the machine, taping the vaporizer to the off position is not recommended practice. Answers B-E are all important steps in making a machine “clean.” Some sources also say that the bellows should be changed as well, although numerous studies have shown an oxygen flush to be sufficient.

Question 38

5 year old boy with a confirmed episode of malignant hyperthermia (MH) one year ago has a successful “clean” anesthetic and is in the PACU at this time with no evidence of MH. The patient is otherwise ready for discharge 30 minutes after being admitted to the PACU. The best next step is to:

Answer 38

Watch the patient for 6 hours and then send them home

Question 39

A 9 year old boy with a remote family history of malignant hyperthermia (MH) has masseter muscle spasm (MMS) after succinylcholine administration. Which of the following is the BEST answer:

A. Discontinue surgery and observe the patient for 6 hours
B. Discontinue surgery and observe the patient for 24 hours
C. Send a stat creatinine kinase (CK) level
D. Administer dantrolene
E. Administer cisatracurium

Answer 39

D: Administer dantrolene

MMS can occur in response to succinylcholine administration in up to 1% of pediatric patients and is discussed in detail in Neonatal question 30. MMS is reason to cancel elective surgery (and observe) or use clean technique for an emergent one. Patients with MMS should be tested for MH susceptibility (caffeine-halothane contracture test). A patient with a high pretest probability of MH (family history, personal history, etc) in which MMS occurs should be considered an MH episode until proven wrong; therefore, emergency therapy should begin. In this setting, further diagnostic tests (answer C) will only delay treatment. Non-depolarizing muscle relaxants will not break the MMS (answer E), see question 35.