UBP 4.6 (Long Form): Pediatrics - Pyloric Stenosis

Question 1

Intra-operative Management:

The patient has been medically optimized for surgery.

How will you induce her?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 1

Because of the risk of aspiration, I would first apply suction to the gastric tube in the lateral, supine, and prone positions to remove as much of the gastric contents as possible.

I would then preoxygenate and perform a rapid sequence induction with cricoid pressure to further reduce the risk of aspiration.

However, prior to induction, I would pretreat with atropine to prevent the significant bradycardia that can occur in infants following succinylcholine administration and laryngoscopy.

Question 2

Intra-operative Management:

What is your main concern during induction?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 2

Assuming the airway is normal and the patient is medically optimized,

my main concern with this induction is the increased risk of aspiration associated with pyloric stenosis.

This is why I would take the precautions of performing a RSI after attempted gastric emptying using an orogastric tube in the lateral, supine, and prone positions.

Question 3

Intra-operative Management:

So, you would use succinylcholine in a neonate?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 3

Given the risk of aspiration in this case, I would use succinylcholine to aid in rapidly securing the airway.

However, I would first treat with atropine to avoid the profound bradycardia and even sinus arrest that may occur with administration to children.

Also, I would recognize that there is increased risk of –

• hyperkalemia,
• cardiac arrhythmias,
• rhabdomyolysis,
• masseter muscle spasm, and
• malignant hyperthermia, when succinylcholine is administered to children.

Question 4

Intra-operative Management:

What is the dose of succinylcholine in neonates?

Why is it higher?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 4

The dose of 2-3 mg/kg is higher in infants secondary to relatively larger volume of distribution.

Question 5

Intra-operative Management:

Is an inhalational induction faster or slower in a neonate when compared to an adult?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 5

An inhalational induction is faster in a neonate, secondary to a higher minute ventilation-to-FRC ratio and increased blood flow to vessel-rich organs.

Additionally, the blood/gas coefficient is lower in neonates as compared to adults.

Question 6

Intra-operative Management:

You place the ETT and are unable to ventilate. What will you do?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 6

I would quickly switch to 100% oxygen, check the circuit, ensure a patent ETT, and attempt to verify proper ETT placement by auscultation and direct larygoscopy.

If I thought the ETT was in the correct place, I would consider bronchospasm the most likely diagnosis, apply positive airway pressure, take steps to deepen the anesthetic with an inhalational agent and/or anesthetic drugs, and administer a B2-agonist.

If the bronchospasm persisted, I would administer a small dose of epinephrine.

Following initial treatment, I would look for evidence of stomach contents in the oropharynx, since the patient is at high risk for aspiration and regurgitant material could have been the cause of the bronchospasm.

Question 7

Intra-operative Management:

You break the bronchospasm and bilateral breath sounds have improved on auscultation, but the airway pressures are still high.

What will you do?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 7

I would again confirm proper ETT placement,

continue to apply gentle positive pressure ventilation,

administer a B2-agonist, and

ensure a sufficiently deep plane of anesthesia.

This could be residual bronchospasm, atelectasis from hypoventilation, or the result of aspiration of gastric contents.

While I would make the surgeon aware that possible aspiration has occurred, bronchoscopy, pulmonary lavage, and antibiotics are probably not indicated even if regurgitant material was noted in the oropharynx.

Question 8

Intra-operative Management:

Are you concerned about hypothermia?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 8

It is important to avoid hypothermia given its association with delayed wakening, respiratory depression, cardiac irritability, and increased pulmonary vascular resistance.

This is of particular concern in this case because neonates are more susceptible to hypothermia with their low fat content, thin skin, and relatively higher ratio of surface area to weight.

Question 9

Intra-operative Management:

Describe temperature regulation in the neonate.

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 9

Neonates produce heat primarily through nonshivering thermogenesis,

which involves the metabolism of brown fat.

This relatively inefficient process may be further limited by the use of volatile anesthetics and in premature and sick neonates who often have reduced fat stores.

Question 10

Intra-operative Management:

Would you extubate this patient in the OR?

How?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 10

Given this patient’s continuing risk of aspiration, and

assuming she was demonstrating adequate spontaneous ventilation, maintaining normocapnea, and had undergone full reversal of nondepolarizing muscle relaxants,

I would extubate her in the OR, when fully awake, and in the lateral position.

However, since she experienced intra-operative bronchospasm, I would administer adequate narcotics and a B2-agonist prior to lightening of anesthesia, followed by intravenous lidocaine just prior to extubation.

Question 11

Post-operative Management:

What postoperative considerations do you have with this neonate?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 11

With this patient’s medical condition, I continue to be concerned about the risk of aspiration and subsequent pulmonary dysfunction.

I am also concerned about the anesthetic complications generally associated with premature neonates such as –

hypothermia, hypoglycemia, retinopathy of prematurity, and postoperative apnea.

Question 12

Post-operative Management:

Is this neonate at increased risk for postoperative apnea?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 12

Yes, she is at increased risk because she is less than 50 weeks postconceptual age and because of the effects of preoperative alkalosis on the pH of the cerebral spinal fluid.

Question 13

Post-operative Management:

What are the risk factors for post-op apnea in premature infants?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 13

The risk factors include –

• low gestational age at birth,
• a history of chronic lung disease,
• a history of apnea and bradycardia,
• multiple congenital anomalies,
• sepsis,
• anemia, and
• neurologic abnormalities.

Additionally, anything that would exacerbate respiratory depression, such as –

• narcotics for pain control, would possibly increase the risk.

Caffeine or aminophylline may be given to reduce the risk.

Question 14

Post-operative Management:

How long will you monitor this patient postoperatively?

• (A 4 kg female infant, delivered 13 days ago presents for surgery.*
• PMH: Preterm baby delivered vaginally at 35 weeks gestation had been doing well until she started vomiting 2 days ago, after which time she became increasingly lethargic. No wet diapers in the last 12 hours.*
• PE: Vital Signs: BP = 74/48, HR = 113, RR = 31, T = 37 C*
• General: Lethargic in appearance, sunken anterior fontanelle, poor skin turgor, capillary refill > 6 seconds*
• Heart: RRR*
• Lungs: CTAB*
• Abdominal: Small abdominal mass 3 cm below the right costal margin*
• Lab: Hct = 51, Na+ = 136 mEq/L, K+ = 3.0 mEq/L, Cl- = 87 mEq/L, HCO3 = 31 mEq/L, pH = 7.49*
• CXR: Normal*
• EKG: Normal)*

Answer 14

Since this patient is less than 50 weeks postconceptional age,

I would monitor her closely for at least 12 hours and maybe 24 hours postoperatively.

If this patient were between 50-60 weeks postconceptional age,

I would consider a shorter period of monitoring.