PICU Quiz

1. A 9-month-old boy presents with diffi culty breathing. His mother states that he has been treated for croup twice already in the last 4 months with similar symptoms. He has had 2 days of upper respiratory tract infection symptoms and now has expiratory stridor on examination. Which of the following is correct?

a. Recurrent acute laryngotracheobronchitis (croup) needs further investigation and should not be ignored
b. Intrathoracic airway obstruction is typically worse during inspiration
c. Extrathoracic airway obstruction is typically worse during inspiration
d. Croup (viral laryngotracheobronchitis) is typically characterized by intrathoracic airway obstruction
e. All are true

2. A patient with acute respiratory distress syndrome has been managed with high-frequency oscillatory ventilation for the past 2 hours. A blood gas study shows pH of 7.48, PaCO2 of 30 mm Hg, PaO2 of 70 mm Hg, bicarbonate level of 22 mEq/L, and oxygen saturation of 97% on a FIO2 of 0.6. Which of the following is the most appropriate intervention?

a. Wean the mean airway pressure.
b. Increase the delta P.
c. Decrease the frequency.
d. Increase the mean airway pressure.
e. Increase the frequency.

3. A 2 year old child is ventilated for 3 days with bronchiolitis. You extubate him today and almost immediately notice a signifi cant stridor. Which of the following is true of this condition?

a. Occurs in 50% of children.
b. Begins within 18 hours, peaks at 48 hours, andresolves by 5 days.
c. Patients with active coughing and very light sedation are less likely to develop this
d. More prevalent in children above 5 years of agewho have undergone neck surgery.
e. All of the above.

4. A 12 year 48 kg boy with deep burns to about 85% body surface area involving most of trunk and lower extremities is admitted to your ICU, intubated and ventilated. His ventilatory parameters are: Synchronized intermittent mandatory ventilation+Pressure Control/Pressure Support, rate 25, pressures (Peak inspiratory pressure over PEEP/PEEP) 32+6/6, (Tidal volume generated 160ml) Inspiratory time 0.9 sec, FiO2 1. ABG shows pH 7.2, pCO2 82, pO2 52, HCO3 18. Chest Radiograph: clear fi elds. What is the most appropriate measure?

a. Acceptable parameters, continue on same settings avoiding further injury to lungs
b. Escharotomy of chest wound
c. Increase PEEP, likely developing ALI (Acute lung injury)
d. Switch to High Frequency Oscillatory Ventilation (HFOV), needs higher Mean Airway Pressure
e. Bronchoscopic toilet of lungs

5. A 15-day-old child is brought in respiratory distress. A Chest radiograph done shows markedly increased pulmonary vascularity. The echocardiogram shows Double Inlet Right Ventricle(DIRV) and confi rms torrential pulmonary fl ows. The vitals: HR 178, BP 50/28, RR 90, SPO2-98%.ABG: pH 7.25, pCO2 35, pO2 90, BE -13, lactate 6.
The child is intubated and initiated on mechanical ventilation. The cardiologist and surgeons plan for pulmonary artery banding which can only happen the next morning. Over the next few hours the child has drop in urine output and the ABG on room air shows- pH 7.20, pCO2 40, pO2 84, BE -17, lactate 9.
Which of the following is the most appropriate step?

a. iNO
b. Nitrogen
c. Epinephrine infusion
d. Increase FiO2
e. NaHCO3 infusion

6. A 9 month old girl presents to the ED with stridor and respiratory distress for the last 2 days, no fevers. She was recently discharged from the hospital about 3 weeks back when she was admitted for sepsis, hypernatremia and encephalopathy needing mechanical ventilation for 4 days during her PICU stay. She was normal on discharge. A laryngoscopy done shows signifi cant obstruction below the cords. Which of the following is likely to be associated with her condition?

a. Sepsis
b. Larger endotracheal tube
c. Gastroesophageal refl ux
d. Eosinophilic esophagitis
e. All of the above

7. A 4 year old child has been on ventilator for streptococcus pneumonia for the last 3 days and is improving in lung condition.Ventilator settings are down and FiO2 requirement is only 0.25. You are worried that he might fail extubation as he has SIADH and positive fl uid balance in past 24 hours. You decide to extubate him from the ventilator. Which of the following statements holds true for his condition?

a. SIADH is likely to improve with improving pneumonia and with discontinuation of positive pressure ventilation.
b. Concurrent frusemide must be given to improve chances of successful extubation
c. Low dose dopamine should be commenced to offset the increase in afterload on extubation
d. Infi ltrates would worsen after extubation with higher chances of reintubation than usual

8. A 7 year old child is admitted in your PICU with fevers, yellow discoloration of eyes and altered sensorium over the last week. On examination you fi nd him deeply icteric, drowsy with fl exion response to painful stimulus. The lab reports show an INR of 4.3. All of the following are appropriate for this child except?

a. Tracheal intubation
b. IV antibiotics
c. Lactulose
d. Vitamin K
e. 3% NaCl

9. All of the following are true regarding periextubation corticosteroids and stridor/ reintubation except

a. Steroids given prophylactically have not shown any benefi t in infants
b. Steroids have shown a benefi t in children with airway abnormalities
c. Multiple doses begun 12-24 hours before extubation are of benefi t in adults
d. Steroids before extubation reduces the risk of reintubation in adults
e. All are true

10. A 15 kg child is on Total parenteranl nutrition(TPN) in your unit. He is getting 1100ml of TPN in a day giving him a total of 1250 kcal, through a central line. He is on 2gm/kg of proteins and 3gm/kg of fats. All of the following statements are true for this child except ?

a. An adequate ratio of non-protein calorie is required to avoid oxidation of exogenous proteins
b. The protein to non-protein calorie ratio is around 1: 30 and adequate
c. The Nitrogen to non-protein calorie ratio is around 1: 200 and adequate
d. This concentration of TPN should not be given through a central line
e. All the statements are true

Quiz: Answers and explanations

1. Answer: c
Acute laryngotracheobronchitis presents with inspiratory stridor and is typical of extrathoracic obstruction. Extrathoracic obstruction worsens during inspiration. Obstruction increases the velocity of air and hence drops the pressures intraluminally (Venturi principle). The surrounding atmospheric pressure collapses the airway during inspiration because of a more negative intraluminal pressure.

2. Answer: e
A child with ARDS is hyperventilated on the HFOV as suggested by the pH and the PaCO2 levels. The SpO2 is reasonable on 60% FiO2 and attempts to wean mean airway pressure would be a little premature. Ventilation (CO2 washout) is a function of tidal volume (read delta P) and frequency on the HFOV. Increasing delta P would washout CO2 even further by increasing the swing of the piston and the tidal volume. Contrary to conventional ventilation, frequency has an inverse relationship to CO2 and increasing the frequency (hertz) would increase the PaCO2.

3. Answer: e
This is the condition of postextubation croup. It occurs in approximately 5% of intubated children and usually resolves in 24 hours. It is more common in patients with frequent coughing episodes and in patients who are more agitated and moving frequently while intubated. It has been shown to be more prevalent in children 1–4 years or age, particularly in association with any type of surgery in the head/neck area.

4. Answer: b
The scenario is of extrinsic restriction of lung expansion most likely due to eschar formations on trunk. Escharotomy of all circumferential burns should be undertaken as an emergency. Some incomplete eschars may need excision too to help chest expansion.

5. Answer: b
This is a situation of single ventricle physiology. Unrestricted pulmonary blood fl ows is causing systemic hypoperfusion and shock.Pulmonary artery(PA) banding is the emergency procedure of choice but in a situation that it cannot be performed immediately inhaled nitrogen or carbon dioxide can be used to induce hypoxemic pulmonary vasoconstriction to improve systemic blood fl ow.

6. Answer: e
Subglottic stenosis is an uncommon complication of tracheal intubation. A larger than adequate tube is the most common association but sepsis, GER and eosinophilic esophagitis have all been implicated in the formation of subglottic stenosis.

7. Answer: a
Lung infection and positive pressure ventilation both cause an inappropriate increase of ADH and cause the body to hold on to free water. Extubation would reverse this and cause spontaneous diuresis. For a child who has improved, use of Frusemide or Dopamine cannot be justifi ed.

8. Answer: c
The child has fulminant hepatic failure. Control of airways in a comatose child, hemodynamic support, prophylactic antibiotics and antiedema measures are all accepted treatment modalities for the child. Lactulose is not preferred because of the risks of aspiration, ileus and lack of outcome benefi ts and is no longer recommended.

9. Answer: d
The Cochrane metanalysis and review on this topic (Khemani RG, Randolph A, Markovitz B. Corticosteroids for the prevention and treatment of post-extubation stridor in neonates, children and adults. Cochrane Database of Systematic Reviews 2009) shows that steroids may be of benefi t in infants and children with airway abnormalities in reducing post extubation stridor. Steroids begun pre-extubation in adults does reduce the incidence of stridor but not of reintubation.

10. Answer: d
An adequate ratio of nitrogenous to total calories is justified to ensure proper utilization of exogenous proteins. The desired ratio of N: NonNitrogen calorie of 1: 250-350 is generally recommended. This is the same as having a protein: non-protein calorie ratio of 1: 25-35. This calorie concentration can be safely given through the central line.

Journal of Pediatric Critical Care

PICU Quiz

Nameet Jerath, MD

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