UBP 4.3 (Long Form): Pediatrics – CDH and Prematurity Flashcards
Secondary Subject -- Prematurity / Respiratory Distress of the Newborn / Pulmonary Hypertension / Umbilical Artery or Vein Access in the Neonate / Retrolental Fibroplasia / Abdominal Compartment Syndrome / Pneumothorax / Neonatal Temperature Regulation / Patent Ductus Arteriosus
Intra-operative Management:
The baby presents for surgery.
Where would you obtain intravenous access?
Does it matter?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
I would obtain central venous access via the umbilical or femoral veins,
avoiding the use of neck veins, which may be needed if ECMO became necessary.
I would also consider placing an upper extremity peripheral line to provide reliable access in case the replacement of the abdominal contents led to increased abdominal pressure and subsequent partial obstruction of the inferior vena cava.
Intra-operative Management:
You decide to cannulate the umbilical vein.
How would you do this?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
To cannulate the umbilical vein I would:
- sterilize and drape the area,
- place caudal traction on the umbilical stump
- (caudal traction facilitates insertion during umbilical vein catheterization;
- cephalad traction facilitates insertion during umbilical artery catheterization),
- carefully insert a soft catheter filled with heparinized solution a distance that approximates the length between the insertion site and the right atrium (the desired position for the catheter tip),
- obtain a radiograph to confirm proper placement at the junction of the inferior vena cava and the right atrium, and
- secure the catheter at the insertion site with suture, antibiotic ointment, and a protective covering.
Intra-operative Management:
You are unable to advance the catheter into the inferior vena cava.
Can you still use the catheter?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
I could still temporarily utilize the catheter for the administration of fluids and medications if I ensured the tip was inserted no more than 2 cm beyond the abdominal surface or to the point where blood was freely aspirated.
Unlike the desired catheter position at the junction of the inferior vena cava and the right atrium, this location would NOT allow for central venous pressure monitoring.
It is important to recognize that sometimes the catheter tip may become wedged in the liver after failing to traverse the ductus venosus on its way to the inferior vena cava.
http://classes.midlandstech.edu/carterp/Courses/bio211/Chap28/figure_28_14_labeled.jpg
Utilizing the catheter in this position can lead to hepatic injury (portal necrosis and cirrhosis) with the administration of hyperosmolar or sclerosing solutions, such as calcium, sodium bicarbonate, and 25-50% glucose.
Clinical Note:
The ductus venosus is a communication present in fetal circulation that allows oxygenated blood from the placenta to bypass the liver; preferentially shunting oxygenated blood to the fetal brain.
Intra-operative Management:
What are complications associated with umbilical vein catheterization?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
Complications associated with umbilical vein catheterization include:
- infection and sepsis,
- thrombosis of portal and mesenteric veins,
- portal cirrhosis,
- endocarditis,
- cardiac tamponade,
- liver abscess,
- hemorrhage, and
- subcapsular hematoma.
Since many of these complications are associated with the duration of cannulation, the catheter should be removed as soon as alternative intravenous access is established.
Intra-operative Management:
If you were going to place the catheter in the umbilical artery, to what position would you advance the tip of the catheter?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
My preference would be to advance the tip of the catheter through the iliohypogastric artery into the descending aorta to the level of T7-T9, recognizing that this positioning may increase the risk for embolization to renal or mesenteric vessels.
Alternatively, the catheter tip could be advanced to just to the level of L3-L5, just above the bifurcation of the descending aorta, placing it below the origin of the renal and mesenteric vessels.
However, the higher position (T7-T9) is recommended - since positioning just above the aortic bifurcation is more difficult to maintain and risks catheter tip migration into one of the iliac arteries with subsequent tissue necrosis.
Intra-operative Management:
Is it acceptable to utilize an umbilical artery catheter for drug administration?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
An umbilical artery catheter can be used for the emergency administration of fluids, blood products, and drugs until alternative access can be obtained.
However, when possible, it may be best to limit the use of an umbilical artery catheter to blood pressure monitoring and blood gas analysis in order to minimize complications associated with its use, such as –
air embolism, exsanguination (i.e. accidental disconnection of stopcock), vasospasm, and refractory hypoglycemia (may occur when the catheter tip is opposite the celiac plexus resulting in the direct infusion of glucose into the vessels of the pancreas with subsequent hyperinsulinemia).
Intra-operative Management:
What FiO2 will you use?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
In establishing the appropriate Fio2, my goal would be to avoid hypoxemia,
which can lead to metabolic acidosis and increased pulmonary vascular resistance,
while, at the same time, avoiding unnecessary exposure to high concentrations of oxygen.
This is important because higher concentrations of oxygen can lead to pulmonary oxygen toxicity (although this would be more clinically significant with prolonged exposure) and would place this neonate under 44 weeks gestation at increased risk of developing retinopathy of prematurity (the risk of retinopathy of prematurity is negligible following vascularization of the retina, which is completed by 44 weeks postconceptual age).
Therefore, if tolerated, I would maintain an oxygen saturation of about 92-96% and a PaO2 of about 60-80 mmHg while monitoring for the development of hypoxemia or acidosis.
Intra-operative Management:
What is the pathophysiology of retinopathy of prematurity (ROP)?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
ROP is a vasoproliferative retinopathy that is multifactorial in origin;
occurring in premature infants who are less than 44 weeks postconceptual age.
Vascularization of the retina begins around the 16th week of gestation and progresses through the 44th week postconception.
Exposure to high concentrations of oxygen leads to vasoconstriction and obliteration of retinal vessels (phase 1), resulting in insufficient vascularization of the retina to meet the metabolic demands that occur with ongoing retina growth.
The relative hypoxia that subsequently develops leads to abnormal neovascularization (the development of new vessels) extending into th vitreous humor.
In severe cases, neonates may experience retinal and vitreal fibrous tissue formation, hemorrhage, and/or retinal detachment (occurs with retraction of scar tissue).
Risk factors for this disorder include:
- hyperoxia,
- prematurity (probably the most important risk factor; especially < 32 weeks and a birth weight of < 1000 g),
- carbon dioxide fluctuations,
- hypotension,
- sepsis,
- red blood cell transfusions,
- cyanotic congenital heart disease,
- respiratory distress syndrome,
- intraventricular hemorrhage,
- corticosteroid therapy,
- mechanical ventilation,
- hyperglycemia,
- maternal diabetes,
- hypoxemia,
- fluctuations in oxygen levels,
- exposure to bright light, and
- maternal antihistamine use within 2 weeks of delivery.
While hyperoxia has long been considered a major component of this neonatal disorder, ROP has been documented to occur in the absence of oxygen supplementation.
Intra-operative Management:
The patient becomes cyanotic after induction.
The pulse oximeter on the right hand reads 95%, and the pulse oximeter on the foot reads 78%.
What do you think is going on?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
A normal reading from the pulse oximeter measuring preductal oxygen saturation (right hand), combined with a low reading from the pulse oximeter measuring postductal oxygen saturation (either foot), suggests –
a signifcant right-to-left shunt through a patent ductus arteriosus
(if the examiner does not stop you, demonstrate more knowledge by discussing what you would do to treat the problem). – see answer to next question
Intra-operative Management:
What would you do?
(Previous Question: The patient becomes cyanotic after induction.
The pulse oximeter on the right hand reads 95%, and the pulse oximeter on the foot reads 78%.)
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
I would administer 100% oxygen,
ensure adequate ventilation, and
take steps to increase systemic vascular resistance (if induction resulted in vasodilation and hypotension) and/or
reduce pulmonary vascular resistance.
Inducing a respiratory alkalosis with hyperventilation, treating any metabolic acidosis with bicarbonate, and ensuring both normothermia and an adequate depth of anesthesia to minimize catecholamine secretions would be helpful in reducing pulmonary vascular resistance.
Intra-operative Management:
The surgeon has returned the abdominal organs to the peritoneal cavity, reavealing a hypoplastic left lung. The medical student doing the case with you asks if you will attempt to expand the collapsed and hypoplastic lung with positive pressure.
How will you respond?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
Intuitively, the immediate expansion of the hypoplastic lung with positive airway pressure seems appropriate.
However, delivering the high airway pressures required to expand the hypoplastic lung places the neonate at considerable risk of pneumothorax, particularly on the contralateral side.
Even a small pneumothorax could be disastrous in this neonate who already has significantly compromised cardiopulmonary function.
Intra-operative Management:
Soon after returning the abdominal organs to the peritoneal cavity, the patient’s blood pressure suddenly drops from 74/42 mmHg to 44/26 mmHg, and the oxygen saturation drops to 68%.
What are you going to do?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
The timing of this hypotension would suggest that the replacement of his abdominal organs into the peritoneal cavity has resulted in – increased abdominal pressure with subsequent compression of the inferior vena cava (leading to reduced preload and cardiac output).
If this were the problem, the surgeon would need to relieve abdominal pressure temporarily, cover the abdominal wound, and proceed with complete closure at a later date.
However, recognizing that there are a number of potential causes for his change in vital signs, I would –
- first switch to 100% oxygen,
- check my monitors for accuracy,
- check the ECG for arrhythmia,
- begin hand ventilation,
- auscultate the chest,
- ensure proper endotracheal tube placement, and
- assess the surgical field for another surgical cause of cardiopulmonary depression.
If there were no pneumothorax, massive bleeding, or other obvious cause,
- I would ask the surgeon to relieve the abdominal pressure,
- reduce my volatile agent,
- administer fluids (volatile agents and hypovolemia can exacerbate the cardiovascular effects of abdominal compartment syndrome), and
- proceed with complete closure at a later date.
Intra-operative Management:
Will you extubate this patient at the end of the procedure?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
I would NOT extube this patient at the end of the case.
Although cardiopulmonary function often improves immediately following surgery, these patients require intensive respiratory care and are at risk for rebound pulmonary hypertension.
Controlled ventilation reduces oxygen requirements, and helps to prevent and treat hypoxemia, hypercarbia, and acidosis, all of which can induce or exacerbate pulmonary hypertension.
Post-operative Management:
You are called to evaluate the neonate postoperatively.
His blood pressure is 52/30 mmHg, his heart rate is 78, and the pulse oximeter reads 62%.
What are you going to do?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
As before, I would increase the Fio2 to 100%, hand ventilate if possible, check ECG for arrhythmia, auscultate the chest, and ensure proper endotracheal tube patency and placement.
Assuming the ETT was properly positioned, I would have a high suspicion for heart failure secondary to hypoxia, pneumothorax, and/or worsening pulmonary hypertension.
Post-operative Management:
Breath sounds are diminished bilaterally.
What are you going to do?
- (A neonate, born at 38 weeks gestation, begins to experience respiratory distress with nasal flaring, sternal retraction, and cyanosis shortly after birth.*
- PE: VS: P = 154, BP = 72/45 mmHg, R = 62, T = 36 C*
- CV: Tachycardia*
- Lungs: absent breath sounds on left*
- Abdomen: scaphoid in appearance*
- Lab: ABG: pH = 7.24, PaCO2 = 57, and PaO2 = 43 on room air*
- H/H = 16.4/56; BS = 45*
- CXR: Right mediastinal shift; loops of bowel, spleen, and liver present in left hemithorax; absence of gas in the abdomen)*
Assuming proper ETT placement, I would treat this as a right-sided pneumothorax, until proven otherwise, since breath sounds were already diminished on the left side and are now diminshed on the right.
Therefore, i would call for a surgeon to emergently place a chest tube, and consider placing a 22-gauge angiocatheter into the second intercostal place, at the midclavicular line, as a temporizing measure until a chest tube could be placed.
