Module 9: Jasmine

Question 1

There are 5 stages of lung development:

Answer 1

• Embryonic
• Pseudoglandular
• Canicular
• Saccular
• Avelolar

Question 2

Embryonic

Answer 2

weeks 3 to 6. Initial budding and branching of the lung buds from the primitive foregut. Ends with the development of the presumptive broncho-pulmonary segment.

Question 3

Pseudoglandular

Answer 3

weeks 6 to 16. By the end of this period, all of the major lung elements, except those required for gas exchange (alveoli), have appeared. Respiration is not possible during this phase, and fetuses born during this period are unable to survive.

Question 4

Canicular

Answer 4

weeks 16 to 24. The lumens of the bronchi enlarge and lung tissue becomes highly vascularized. By week 24, respiratory bronchioles and alveolar ducts have developed from the terminal bronchioles. Respiration is possible towards the end of this period.

Question 5

Saccular

Answer 5

weeks 24 to 40. The important blood-air barrier is established. Specialized cells of the respiratory epithelium appear at this time, including type I alveolar cells across which gas exchange occurs, and type II alveolar cells which secrete pulmonary surfactant. This surfactant is important in reducing the surface tension at the air-alveolar surface, allowing expansion of the terminal saccules.

Question 6

Avelolar

Answer 6

Alveolar period, birth to 2 years of age. During this stage the terminal saccules, alveolar ducts, and alveoli increase in number.

Question 7

The lungs are the last of the vital organs to complete development, and fetal lung development is not complete until:

Answer 7

• the alveoli possess an adequate surface area for gas exchange
• the pulmonary vascular system have sufficient capacity to transport an adequate amount of blood through the lungs for gas exchange
• the alveoli are structurally and functionally stable
• alveoli are elastic enough to overcome the stretching associated with breathing

Question 8

More on lung development

Answer 8

The infant’s gestation when born will reflect the stage of lung development and their risk for respiratory complications. Infants born before 33 weeks will most likely need assistance to support respiration by either a ventilator or a CPAP machine, due to lung immaturity. In some circumstances doctors who anticipate a premature delivery of an infant will give the mother steroid shots to promote lung develop before delivery.

Jasmine, being born at 28 weeks, is a prime example of lung immaturity; however, it is important to remember that even a birth at 40 weeks gestation does not signal the end of lung development.

Question 9

Structural development of the lungs occurs late in gestation and continues over the first few years of life:

Answer 9

• There is an increase in the total number of alveoli.
• Lung volume will increase.
• There is an increase in alveolar surface area.
• Lung weight will increase.
• Oxygen intake will increase as the infant body weight increases.

Question 10

CPAP

Answer 10

Continuous Positive Airway Pressure, or CPAP, is a non-invasive form of respiratory support that applies continuous pressure on an infant’s airway, so that at the end of expiration, some air remains in the lungs, and the alveoli do not collapse. CPAP helps reduce surface tension, prevents atelectasis, and maintains adequate lung volume, particularly functional residual capacity (FRC) and tidal volume. This reduces the infant’s reliance on tachypnea as a way to eliminate carbon dioxide.

Unfortunately, CPAP does not work for all infants. To be successful on CPAP as a mode of respiratory support you need to have a respiratory drive and adequate respiratory muscles to support and sustain good respiratory effort and tidal volumes.

Question 11

Mechanical Ventilation

Answer 11

Mechanical ventilation is an invasive form of respiratory support that assists or replaces spontaneous breathing. Because of the associated pulmonary pathophysiology, infants with BPD can and often do experience hypoxia, hypercapnia, and apnea and, therefore, may require mechanical ventilation. Unfortunately, mechanical ventilation, while it does effectively treat hypoxia, hypercapnia, and apnea, also increases pulmonary damage: the very damage that is contributing to hypoxia, hypercapnia, and apnea. Mechanical ventilation is a good example of a therapy that has many benefits but that also increases an infant’s vulnerability.

Question 12

Jasmine was born at 28 weeks gestation, Using the Stages of Lung Development graph found on the “Lung Development” page and the Smith article, describe her stage of lung development and why she is at risk?

Answer 12

Jasmine was born during the saccular phase of lung development, which is about the midpoint of fetal development, when the lung volume increases markedly due to saccule development, and subdivision of the saccules into alveoli commences. During this time, surfactant production is just beginning. Jasmine’s lungs are not fully developed and also lack surfactant. This will put her at risk for respiratory complications that may require respiratory support.

Question 13

What if Jasmine was born at 24 weeks gestation? How would this affect her lung development/risk?

Answer 13

If Jasmine was born at 24 weeks she would be in the cannicular/saccular stage of lung development. Her lungs will be underdeveloped and lacking in surfactant. Jasmine would most definitely experience respiratory distress and need respiratory support.

Question 14

Bronchopulmonary Dysplasia

Answer 14

Respiratory distress syndrome (RDS) and its effects were discussed in Module 3 (Sarah). Recall that RDS is the most common cause of respiratory distress for preterm infants and often requires mechanical ventilation and oxygenation to prevent hypoxia and to assist with gas exchange. The long-term sequelae of RDS can be significant. One of the consequences of RDS is bronchopulmonary dysplasia (BPD).

Bronchopulmonary dysplasia (BPD) is associated with increased mortality and significant long-term cardio-respiratory and neuro-developmental sequelae (Schulzke, 2010). It is the most common chronic lung disease in preterm infants and is characterized by respiratory distress and impaired gas exchange.

here are many definitions of BPD within the literature but the most commonly accepted definitions include the need for oxygen supplementation at 28 days of life or at 36 weeks Postmenstrual age

Question 15

old and new BPD

Answer 15

timing and exposure of pulmonary insults during lung maturation will either result in an arrest or delay in lung development (new BPD) or a structural injury (old BPD).

Question 16

Old BPD

Answer 16

Gestational age: 32 weeks
Infants at risk: more mature
airway injury: severe
Interstitial fibrosis: severe
alveoli: Well developed in regions without fibrosis, some over-inflation
Causes:Oxygen toxicity
Ventilator-induced injury
Barotraumas/volutrauma
Infection

Question 17

New BPD

Answer 17

Gestational age: 24-26 weeks
Infants at risk: low gestational age
airway injury: mild to none
Interstitial fibrosis: minimal
alveoli: Disruption in lung development
Vascular and alveolar growth impairment
Large, simplified alveoli
Dysmorphic capillary configuration
Variable interstitial cellularity

Causes: Interference with lung development
Infection
Oxygen toxicity
Ventilator-induced injury
barotrauma/volutrauma
Infection
Perinatal, postnatal

Question 18

Using the readings and figure by Deakins (2009) describe how each of the following affects an infant’s lung development.

Intrauterine Lung Development: Infection/Cytokines

Answer 18

Reduction in alveolar development

Question 19

Intrauterine Lung Development: Stress

Answer 19

Pro-inflammatory cytokines are released in response to oxidative stress and cause inflammation

Question 20

Intrauterine Lung Development: Antenatal Glucocorticoids

Answer 20

Accelerates the development of type 1 (gas exchange) and type II (surfactant) alveolar cells.

Question 21

Initiation of Ventilation

Answer 21

Can cause ventilator induced lung injury (alveolar damage, fibrosis, pulmonary edema)

Question 22

Postnatal Lung Development: Inflammation, Oxygen, Over Distension, Infection

Answer 22

Alters surfactant development and production, reduction in alveolar development

Question 23

Postnatal Lung Development: Nutrition

Answer 23

Optimizes caloric needs for lung growth and development

Question 24

Postnatal lung Development: Glucosteroids

Answer 24

Anti-inflammatory effects on lung that can improve ventilation

Question 25

What risk factors (prenatally and postnatally) have placed Jasmine at an increased risk for developing BPD?

Answer 25

born at 26 weeks gestation
Denise had a prenatal infection
potential for infection with cerclage insertion
required weeks of mechanical ventilation
oxygen supplementation
history of a PDA

Question 26

Describe care, both prenatally and postnatally, that can help to minimize or prevent BPD.

Answer 26

Ultimately preventing preterm birth would prevent BPD:

Prenatally:

antenatal corticosteroids
antibiotics to treat infections
Postnatally:

minimize invasive ventilation
minimize hyperoxia
administer surfactant
early detection and treatment of PDA
caffeine administration

Question 27

Analyze Jasmine’s blood gas.
pH – 7.35
pCO2 – 50
pO2 – 39
HCO3 – 28

Answer 27

pH – normal
pCO2 – high
pO2 – low (but not accurate as this is likely a capillary blood gas)
HCO3 – high
Compensated Respiratory Acidosis

Question 28

BPD affects infants’ blood gases.

Answer 28

Typically their pCO2 will be elevated; recall that the accumulation of CO2 is a result of hypoventilation, owing to damaged (inflamed, scarred, atelectatic, hyperinflated) alveoli.
Initially, the elevated pCO2 produces an acidotic pH, often below 7.30.
Over time, the kidneys compensate for the chronic respiratory acidosis by retaining HCO3–, a base.
The combination of excess CO2 (acid) and increased HCO3– (base) results in a neutralized pH. In other words, over time, the pH returns to normal or near normal.
This process is known as compensation and, in infants with BPD, results in a compensated respiratory acidosis. Jasmine’s most recent blood gas is a good example of compensated respiratory acidosis.

Question 29

In your own words, explain why infants with BPD need to be carefully weaned from mechanical ventilation and supplemental oxygen.

Answer 29

Atelectasis, scarring, and pulmonary arteriolar changes all conspire to keep infants with BPD dependent on supplemental oxygen and mechanical ventilation. As a result, infants with BPD are quite dependent on the very treatments that are contributing to ongoing pulmonary damage. In addition, pulmonary reserves are minimal. This means that minor deterioration in lung function and/or minor withdrawal of treatment can initiate major setbacks for these infants. For example, weaning oxygen too quickly can result in pulmonary vasoconstriction. This leads to decreased perfusion of pulmonary vascular beds, and as a result of the poor pulmonary perfusion: hypoxia. The hypoxia may be severe enough to require more supplemental oxygen than the infant was receiving prior to being weaned.

Question 30

What type of respiratory support could you provide to Jasmine that would help her to be able to wean her oxygen requirements?

Answer 30

• minimize oxygen consumption by maintaining normothermia, and managing pain and discomfort
• provide developmentally supportive care
• monitor blood gases, O2 saturation (via pulse oximetry), Hct, CXR
• assess color, HR, RR, work of breathing, air entry
• administer diuretics to reduce pulmonary edema
• maintain fluid balance
• wean appropriately and monitor closely

Question 31

What do you think about Jasmine’s current condition? Summarize how you think she is doing, based on what you know about BPD and what you have read about Jasmine.

Answer 31

Jasmine’s lungs seem to be just barely meeting her needs, with supplemental oxygen. Her blood gases demonstrate that while ventilation is adequate, her CO2 is slightly elevated, but her kidneys are able to compensate. Her respiratory rate and indrawing suggest increased work of breathing. Her desaturation illustrates poor reserve and limited ability to cope with increased oxygen demands. Jasmine is doing OK without mechanical ventilation, but could easily deteriorate.

Question 32

What are some of the other problems that could be causing Jasmine’s deterioration?

Answer 32

worsening BPD
sepsis
feeding intolerance – too much volume may be putting pressure on Jasmine’s diaphragm and causing difficulties breathing

Question 33

Is there information normally obtained in a physical assessment of an infant that we don’t have in this case?

Answer 33

There are several pieces of information that we don’t have that would be of great benefit:

urine output
blood pressure
peripheral pulses
central and peripheral perfusion
amount and frequency of feeding

Question 34

What are the causes of pulmonary hypertension in infants with BPD?

Answer 34

abnormal lung development

Question 35

Is Jasmine demonstrating any clinical responses that would suggest that she may be developing pulmonary hypertension?

Answer 35

Jasmine’s pulmonary vasculature can definitely be causing pulmonary hypertension. Jasmine’s cardiovascular system must work harder to overcome the increased pressure within the lungs. In response, the right side of the heart works harder to move the blood through these arteries and it becomes enlarged. Eventually overworking the right side of the heart may lead to right-sided heart failure.

Jasmine’s increased weight, puffy hands and feet, moist chest, indrawing, restlessness, decreased tolerance of handling and increasing oxygen needs all suggest that she may be developing CHF.

Question 36

BPD and Diuretic Therapy

Answer 36

The most commonly used diuretics are thiazides (hydrochlorothiazide) in combination with a potassium sparing (spironolactone) diuretic or Lasix. Used in combination and given on a regular basis, these medications work to decrease edema, particularly pulmonary edema. In this way, they can improve lung compliance.

Question 37

BPD and Feeding

Answer 37

Prematurity is yet another factor that can make feeding infants with BPD challenging. Disorganized suck and swallow, immature oral musculature, and an inability to engage in nutritive sucking are common feeding challenges for premature infants. Jasmine, at 37 weeks corrected age, would not be expected to have these problems; however, the development of her feeding abilities may have been delayed by her illness, and she may experience problems more typical of infants at lower gestational ages.

Negative perioral experiences may also undermine Jasmine’s ability to feed orally. Oral intubation, oral suctioning, and insertion of oral gavage feeding tubes are all thought to contribute to a problem often referred to as “oral aversion.” It develops in some infants who have frequent, repeated, and unpleasant experiences with these procedures. They associate pain with oral stimulation, making it difficult for them to accept a nipple. Oral aversion can often be quite challenging and can continue into their toddler years.

“Pacing” is another important aspect of feeding infants with BPD. Pacing means paying attention to individual infant cues and removing the source of fluid as needed so that an infant does not become unstable. A breast-fed infant will need less pacing than a bottle-fed infant as the flow of milk from the breast is more controlled by the infant.

Skin-to-skin contact with the mother and non-nutritive sucking are some interventions that have been shown to be helpful in establishing feeds.

Question 38

What are some of the side effects of diuretic therapy that Jasmine is at risk for? What are the nursing implications?

Answer 38

Fluid and electrolyte imbalances are the major side effects associated with diuretic use. Liver and renal damage can occur with long-term use. Regarding fluid and electrolyte balance, sometimes these infants get into a cycle of hyponatremia (due to diuretics), which is treated by adding sodium to either feeds or IV fluid. Too much supplemental sodium can lead to fluid retention, which is treated by increasing diuretic doses. This can lead to hyponatremia …and so on. To avoid this problem, clinicians should avoid over treating both hyponatremia and fluid over retention.

Question 39

Describe why management of infants with BPD can be viewed as a “balancing act”, particularly in terms of fluids, calories, and respiratory status. Think about the cardiopulmonary sequelae of BPD.

Answer 39

Caring for Jasmine involves weighing and balancing risk and benefits. Once begun, weaning of Jasmine’s oxygen is closely evaluated for efficacy and tolerance. Close observation and monitoring and frequent re-evaluation of goals and progress are required. Because nurses know infants like Jasmine well, they play a key in evaluating weaning.

Question 40

How could you support Jasmine to be successful at breastfeeding?

Answer 40

• alternate nipple and gavage feeding to decrease tiredness
• feed upright
• reduce stimulation during feeds
• pace all care, including feeds, based on infant cues
• reduce stress and handling immediately prior to and after feeds
• increase supplemental O2 during feeds as needed
• use high calorie formulae or fortified breast milk