Module 5: Respiratory Distress Syndrome Flashcards
What is a key aspect of early intervention for infants at risk for RDS?
- stabilization
- early intervention can prevent the downward spiral described above in which surfactant deficiency leads to respiratory distress and respiratory distress interferes with surfactant production.
Describe what Wendy should check and prepare for this admission. Use the ACoRN Primary Survey of the six main areas of potential concern to guide your response.
Respiratory:
- check for functioning blended gas source with a bag with manometer/neopuff and appropriate size masks
- Make sure a transcutaneous C02 monitor is ready for use.
- gather an oxygen saturation monitor and probe, and ECG leads.
- Suction catheters and functional suctioning set up would need to be present.
- Monitors and alarms should be set per unit policy.
- Assessment of rate and respiratory effort would be ongoing.
Cardiovascular:
- Initial vital signs will include blood pressures to monitor for hypotension
- The appropriate sized B/P cuff will be needed- having a few sizes on hand is prudent.
- ensure that the equipment needed for insertion of an UAC is available (sterile line tray and supplies, fluids, infusion pump).
- Ongoing assessment of HR, color, pulses, perfusion and blood pressure will be incorporated into care.
Surgical Conditions:
- There is no history in this case to suggest that surgical intervention will be anticipated imminently.
neurology:
- Flexing of infant’s limbs to midline, providing containment and tucking, and trying to facilitate a quiet environment to support and facilitate infant organization and transition.
- have a warm, nest prepared for baby.
- Assessment of tone and monitoring for abnormal movements and jitteriness will be performed.
fluid and glucose:
- provide IV glucose for metabolic functioning.
- An IV pump will be needed.
- Equipment for insertion of a peripheral line should also be assembled. I
- have a glucometer available to monitor sugars and sample from either capillary or umbilical arterial route.
- Other labs to consider would include complete blood count with differential, possibly blood cultures and blood gas.
- Feeds are usually started in small volumes, after stabilization.
thermoregulation:
- It is of utmost importance that we keep Robyn in a neutral thermal environment in which she uses the least energy, oxygen and calories to maintain a normal temperature.
- a preheated radiant warmer and warm linen is needed in both the operating room and nursery.
- At birth, NRP guides practitioners to place the infant (for infants < 35 weeks) wet-in-bag at birth to decrease convective heat loss.
- Once stabilized in the unit, I would transfer the baby to a prewarmed, humidified incubator, and remove the bag.
- Careful temperature control is imperative in all VLBW infants and is especially important in infants with RDS to minimize metabolic demands and oxygen consumption.
- RDS can limit oxygen uptake leading to hypoxia which limits the ability of an infant to increase their metabolic rate when cold stressed, resulting in a fall in body temperature.
- Skin probe temperature monitoring should be applied to follow trending of temperature and decrease need to disturb the baby with axillary checks.
Interpret this gas:
pH: 7.26
PaCO2: 54
PaO2: 56
HCO3: 23
BE: 21
pH 7.26 acidosis
PaCO2 54 high normal (hypoventilation)
PaO2 56 low normal (poor diffusion of O2)
HCO3 23 normal
- respiratory acidosis
- this is what I would expect of an infant with RDS.
- The elevated pCO2 reflects hypoventilation. In RDS, hypoventilation is largely due to atelectasis.
- The low pO2 reflects both hypoventilation and poor diffusion of oxygen across the alveolar-capillary membrane.
- Poor diffusion may be due to edema and the large distance between alveoli and capillaries.
- The low pH is due to the effects of respiratory acidosis (pCO2).
Why are preterm infants prone to respiratory distress?
surfactant deficiency
- RDS is a condition caused by lack of pulmonary surfactant … (which) results in decreased lung volume and increased work of breathing
**This is why infants with RDS often require respiratory support to provide oxygenation and ventilation to achieve adequate respiration and ease their work of breathing.
What are some other reasons (aside from prematurity and surfactant deficiency) cause of respiratory distress (3)?
- Transient Tachypnea of the Newborn TTNB
- Pneumonia
- Pneumothorax
- Neuromuscular disorders
- Congenital abnormalities of the lung, chest wall or diaphragm
- Congestive Heart Failure
- Persistent Pulmonary Hypertension PPHN
- Meconium Aspiration Syndrome MAS
Is the 28-week gestation infant in the case at risk for any respiratory distress? If so, why?
- This infant is at risk for Respiratory Distress Syndrome.
- At 28 weeks gestation, the Type II surfactant cells, responsible for the production and secretion of surfactant, are not fully developed.
- This lack of surfactant causes the infant’s alveoli to collapse therefore their functional residual capacity (FRC) is not established.
- This all causes increased energy output in an already compromised infant.
- Merenstein and Gardner (2011) further explain that, “this infant’s immature lungs cannot support oxygenation and ventilation because her alveolar saccules are insufficiently developed, causing a deficient surface area for gas exchange. (Further), the pulmonary capillary bed is deficient and the interstitial mesenchyme is present to a greater extent, increasing the distance between the alveolar and the endothelial cell membranes” (p. 636).
- There is also a lack of development of the pulmonary capillary bed, compliant rib cage, stiff lungs and weak respiratory muscles.
- In addition, this infant has also experienced acute stress due to maternal bleeding.
What other potential health challenges leading to respiratory distress could this infant experience?
One health challenge I would want to rule out is sepsis or pneumonia.
- Although membranes have only been ruptured for 10 hours, there may be bacterial colonization which is not creating any maternal problems.
- There is also the factor that premature infants are at greater risk to a sepsis/pneumonia due to immaturity of the lungs and immune system.
- I remember a 28week gestation infant that I looked after just recently. She presented very similar to Robyn, minus maternal bleeding, and was found to have pneumonia secondary to H. influenza which had been contracted via the birth canal. Mother was asymptomatic.
A second health challenge I would anticipate this infant experiencing is TTN (transient tachypnea of the newborn) due to a cesarean birth.
- There may be some retained fetal lung fluid.
- However, this generally affects term or near to term infants’ more than preterm infants.
What other information would you like to have to assist you in anticipating this infant’s respiratory status?
I would like to gather several pieces of information:
- First, has this mother received any corticosteroids, such as Dexamethasone? If so, how many doses and when in relation to the planned delivery? If corticosteroids have been given, this infant may have less of a problem with RDS.
- Secondly, does mom have any history of infection (urinary tract, Group B streptococcus)? If so, is she being treated with antibiotics?
- Thirdly, how long has she been bleeding, and how much blood has she lost? With large blood losses, I would be anticipating problems with shock in this infant.
What does RDS stand for?
Respiratory Distress Syndrome (RDS)
once referred to as Hyaline Membrane Disease (HMD), is the most common respiratory disorder associated with preterm birth.
RDS occur as a result of what 2 things?
As a result of:
- pulmonary hypoperfusion and
- ischemia
What kind of trajectory does RDS follow?
Decreased lung volume due to surfactant deficiency.
- Decreased lung compliance
- Atelectasis
- Hypoxemia (oxygenation) and acidosis (ventilation)
Ventilation/Perfusion (V/Q) mismatch and hypoventilation.
- Increased pulmonary vascular resistance (PVR)
- Decreased pulmonary perfusion
Increased capillary permeability
- Pulmonary edema
Formation of hyaline membrane
- Increased diffusion gradient
Is the incidence of RDS inversely proportional to GA?
yes
- the incidence of RDS is inversely proportional to gestational age and
- occurs most frequently in infants of less than 1200g and 30 weeks gestation
What is the difference between respiratory distress and RDS?
- Respiratory distress refers to the way that infants respond to a variety of health challenges that interfere with gas exchange.
- There are several causes of respiratory distress, including TTN, meconium aspiration, infection, and RDS. RDS is a particular syndrome which occurs as a result of surfactant insufficiency and leads to respiratory distress.
Respiratory distress due associated with RDS is due to what 3 pulmonary challenges?
- immature lung structures,
- small and few alveoli, and
- surfactant deficiency.
What is surfactant?
a biochemical substance that lines the walls of the alveoli
What are 2 role of surfactant?
- to lower alveolar surface tension,
- helping to prevent alveolar collapse (atelectasis) at the end of an exhaled breath.
What are 3 things surfactant deficiency leads to?
- leads to increased alveolar surface tension and
- decreased lung compliance,
- therefore resulting in a tendency toward atelectasis.
What is functional residual capacity (FRC)?
- when infants exhale, some air is left in the alveoli at the end of the exhaled breath.
What is the purpose of FRC?
- to make the subsequent breath easier by allowing inflation to occur from a position of partial rather than complete collapse of the alveoli
What is the balloon analogy?
- It is easier to inflate a balloon if you inflate it once and, rather than letting all of the air out, you keep some air in the balloon (FRC) by pinching with your fingers and then re-inflate the balloon.
- Infants’ alveoli work the same way. It is easier for an infant to take a breath if some air remains in the alveoli at the end of the previous breath.
**Surfactant is a substance that allows this to happen by preventing alveolar collapse
What is the trajectory is theres inadequate surfactant?
With inadequate surfactant
- the FRC decreases,
- the alveoli become more atelectatic and,
- as a result, more effort is required for inhalation.
- In this way, the work of breathing increases for infants with surfactant deficiency.
- Breathing at a rate > 60 breaths per minute, with few and undeveloped alveoli, a compliant chest wall, inadequate surfactant, worsening atelectasis and weak respiratory muscles
- means that preterm infants with RDS tire very easily!
What are the five cardinal signs of respiratory distress?
- Indrawing
- Tachypnea
- Nasal flaring
- Grunting
- Cyanosis
What are the responses to inadequate gas exchange: O2 level?CO2 level? pH?
- Hypoxia: low O2
- hypercapnia: high CO2
- acidosis: low pH
Tachypnea is an attempt for?
- to compensate for hypoxia and hypercapnia by increasing minute ventilation
Indrawing occurs as a result?
- as a result of a compliant chest wall.
Nasal flaring is an attempt for?
- an attempt to decrease the work of breathing by decreasing airway resistance.
Grunting reflects what?
- an infant’s attempt to prematurely close his/her glottis in order to prevent alveolar collapse by keeping some air in the alveoli at the end of a breath.
Cyanosis reflects what?
- reflects (indirectly) hypoxia in that cyanosis results from hemoglobin that is not saturated with oxygen.
Why is cyanosis an unreliable assessment of oxygenation?
- because cyanosis may be due to either too little oxygen or increased circulating fetal hemoglobin.
**fetal hemoglobin has a high affinity for oxygen, making it less available to the tissues
Why are early responses to RDS compensatory (tachypnea, grunting, nasal flaring)?
- are aimed at overcoming hypoxia, hypercapnia, acidosis, and the increased work of breathing.
- Over time, these compensatory responses (particularly tachypnea) fail to adequately compensate and the result is worsening hypoxia, hypercapnia, and acidosis.
- Hypoxia, hypercapnia, and acidosis, in turn, interfere with surfactant production, making the problem all the worse.
- This is often referred to as the downward spiral or vicious cycle of RDS.