Module 6: Bronchopulmonary Dysplasia Flashcards
1
Q
What are 2 major factors contributing to the etiology of BPD?
A
- prematurity and
- mechanical ventilation
2
Q
What are 4 major risk factors of BPD?
A
- preterm birth,
- the need for supplemental oxygen and positive pressure ventilation,
- patent ductus arterious (PDA) and
- pre- and postnatal infection
**these risk factors trigger a systemic and pulmonary inflammatory response
3
Q
What are the two major forms of BPD?
A
- “classic/old” or severe and
- “new” or mild.
**old BPD is more severe
4
Q
What is the classic “old” BPD?
A
The severe form of chronic lung disease is seen less frequently due to the current treatment and management of infants suffering from respiratory distress (surfactant replacement, CPAP and ventilation, limiting hyperoxia).
5
Q
Injury to relatively immature and surfactant-deficient lung is inflicted secondary to?
A
- high inspired oxygen concentrations (through production of free radicals) and
- high positive airway pressures (causing pulmonary barotrauma).
6
Q
What are 2 things chronic lung disease characterized by?
A
- increased airway resistance resulting from airway inflammation, and
- to bronchial hyperresponsivenes.
7
Q
What are two conditions infants with severe chronic lung disease develop?
A
- tracheomalacia and/or bronchomalacia,
- resulting in atelectasis and/or hyperinflation due to dynamic airway obstruction.
8
Q
What does infant with “new” or mild form of BPD require?
A
- only low or moderate concentrations of oxygen and mechanical ventilation with low pressures, and usually respond favorably to the administration of surfactant
9
Q
What is the lung development at 24-28 weeks of gestation?
A
- (the canalicular stage of human lung development extends to 26-28 weeks gestation) the lung is just beginning to develop into a gas exchanging organ.
- In the saccular (primitive alveolar) stage the distal saccules are alveolarised with parallel development of the alveolar capillary bed;
- alveoli are present at approximately 32 weeks.
10
Q
Why is that the most important pathogenetic factors of infants who develop new BPD is not oxidant injury and mechanical ventilation?
A
- premature birth with initiation of pulmonary gas exchange interrupts normal alveolar development.
11
Q
What are the lungs of infants with new BPD is characterized by?
A
- minimal alveolarisation,
- less airway epithelial disease,
- less severe vascular disease, and
- less interstitial fibrosis compared with lungs with alternating zones of overdistention and atelectasis in infants with severe BPD.
12
Q
What is the new BPD understood to be reflect of?
A
- is understood to reflect extreme lung immaturity with an arrest of alveolar growth and development and
- an inflammatory response to treatment induced injury that leads to cycles of lung injury and repair.
13
Q
What is the characteristic of old BPD
A
GA: 32 weeks
Infants at risk: more mature
BW: 1900g
- Airway injury: severe
- Interstitial fibrosis: severe
- Alveoli: Well developed in regions without fibrosis
- Causes: Oxygen toxicity and mechanical ventilation
14
Q
What is the characteristic of new BPD
A
GA: 24-26 weeks
Infants at risk: LGA
BW: 600g
- Airway injury: mild to none
- Interstitial fibrosis: minimal
- Alveoli: Disruption in lung development (Vascular and alveolar impairment, Large simplified alveoli, Dysmorphic capillary configuration)
- Causes: interference with lung development
15
Q
What are 2 primary culprits in the development of BPD?
A
- birth weight and gestational age
- although family predisposition to asthma, PDA, etc. have been associated with development of BPD
16
Q
What is the relationship between free oxygen radicals and the development of BPD?
A
- We know that premature infants are prone to hypoxia.
- Under these hypoxic conditions, these infants often require oxygen therapy.
- However, not only can the rate of production of these (free oxygen radicals) exceed the capacity of these protective systems but also the systems themselves are immature and functioning at a lower level than those of the adult.
- Further, these free radicals have a direct toxic effect on pulmonary epithelial cells, causing cell membrane injury, enzyme inactivation and structural protein damage.
- Because of these damaging effects of free oxygen radicals, oxygen is not a harmless drug!
- Unfortunately, infants with BPD need supplemental oxygen … this supplemental oxygen, in turn, contributes to the ongoing damage to infants’ lungs.
17
Q
What is the relationship between capillary leak syndrome and BPD?
A
- Capillary leak syndrome refers to the damage done to pulmonary capillaries, partly as a result of free oxygen radicals and partly due to the inflammatory process occurring in damaged lungs.
- Capillary leak syndrome results in loss of integrity of the pulmonary capillary walls.
- This enables fluid and protein that is normally confined to the vascular bed to leak into the lung tissue.
- This results in pulmonary edema and further lung damage.
18
Q
Use your own words to describe the damage that occurs in the lungs of a premature infant who is receiving both positive pressure mechanical ventilation and supplemental oxygen.
A
- premature infants who require mechanical ventilation incur pulmonary damage because their immature lungs cannot withstand the damaging effects of oxygen toxicity (free radicals) and barotrauma (high inflating pressure).
- The result is alveolar and bronchiolar inflammation, edema, necrosis, atelectasis, overdistention, fibrotic scarring, and loss of elasticity.
- Unfortunately, all of this damage often means that further oxygen and ventilation support is required … and a vicious cycle of damage to lung tissue is established.
19
Q
How can nurses either prevent or minimize BPD?
A
- Ultimately, preventing preterm birth would prevent BPD!
- Failing that, preventing the initial respiratory distress due to RDS that preterm infants develop would help to prevent and/or minimize BPD.
- Failing that, understanding the vicious cycle of BPD and providing care aimed at breaking the cycle would help to prevent and minimize BPD.
- Specifically, it is helpful for nurses to aim their care at both supporting infants’ normal ventilation and minimizing infants’ oxygen needs.
For example:
- minimizing pain, stress, and handling would serve to decrease oxygen consumption.
- Maintaining thermal regulation would decrease oxygen consumption.
- Maintaining Sp02 within target parameters, helps to prevent hypoxia and hyperoxia.
- Proper positioning can both decrease stress for infants and can serve to support normal breathing.
Reflect also upon resuscitation of these vulnerable infants.
Ensuring adequate, effective resuscitation with maintenance of body temperature is essential for reducing the incidence and severity of this disease.
20
Q
What does infant with BPD is very labile?
A
meaning that it can change quickly without much warning.
21
Q
What is one reason for the lability of infant with BPD?
A
- one of the reasons for this lability is that the lungs of infants with BPD are often damaged to the extent that there is very little in the way of respiratory reserve.
- Minor changes in an infant’s condition, such as a small amount of pulmonary edema, a small amount of secretions, fluid overload, a slight increase in atelectasis - any of these changes can cause an infant with BPD to decompensate.
22
Q
What is another reason for labile respiratory status of infants with BPD?
A
- relates to the effect of hypoxia on pulmonary blood vessels.
- Hypoxia causes pulmonary vasoconstriction.
- This, in turn, leads to decreased pulmonary perfusion.
- Decreased perfusion leads to further hypoxia, which increases pulmonary vasoconstriction.
- A vicious cycle of hypoxia and pulmonary vasoconstriction can become established in these infants.
23
Q
What the range of O2 saturation be for infant with BPD?
A
- 88-92% if < 36 weeks gestation and
- 90-94% if > 36 weeks gestation,
***while being mindful that hyperoxia is detrimental as well.
24
Q
How does BPD affect infants blood gases?
A
- Typically, pCO2 is elevated; accumulation of CO2 is a result of decreased elimination, 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.
- This process is known as compensation and, in infants with BPD, results in a compensated respiratory acidosis.
25
In your own words, explain the relationship between the pathophysiology of BPD and the difficulty weaning infants with BPD from mechanical ventilation and supplemental oxygen. In other words, why do infants with BPD need to be carefully weaned from mechanical ventilation and supplemental oxygen?
- Atelectasis, scarring, and pulmonary arteriolar changes all conspire to keep infants with BPD dependent on supplemental oxygen and mechanical ventilation.
- Atelectasis, for example, often worsens without the high inflating pressures of mechanical ventilation.
- Scarring means that diffusion of oxygen across the alveolar membrane is inefficient leading to high supplemental oxygen needs.
- Pulmonary alveolar changes are such that pulmonary hypertension and decreased pulmonary perfusion occur in response to hypoxia.
- 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.
- This leads to hypoxia because of poor pulmonary perfusion
- The hypoxia may be severe enough to require more supplemental oxygen than the infant was receiving prior to being weaned!
Similarly, weaning inspiratory pressures too quickly can result in atelectasis.
- Atelectasis results in decreased gas exchange.
- Decreased gas exchange results in CO2 accumulation and respiratory acidosis.
- Acidosis causes pulmonary vasoconstriction, adding to the problem of gas exchange.
- In the end the infant may require higher inspiratory pressures to reverse the effects of weaning pressure too quickly!
26
What do you think about the plan to wean Abby today?
Weaning is always the goal when caring for infants with BPD - the sooner they can be without mechanical ventilation and supplemental oxygen, the sooner they can escape the ongoing damage caused by these treatments. Have we explored noninvasive respiratory support with Abby? Having said this weaning, in order to be successful rather than creating a setback, must be carefully timed, initiated, conducted, and evaluated.
If Abby is not tolerating handling well on her current ventilation and oxygen settings, is it reasonable to expect her to tolerate being weaned? Further, we don’t know what it is that is causing Abby’s intolerance of handling and her increased oxygen needs. What is her respiratory drive like? If some pulmonary or non-pulmonary pathology is at work here, we need to find out what it is before we proceed with weaning or any other changes in her treatment.
27
What will you tell Abby’s parents, Denise and Etienne, when they call or come in to visit?
- In my view, honesty is always the best policy with parents, particularly with parents who have had infants in hospital for long periods of time
- Over time, these parents have generally established collaborative relationships with health care professionals.
- They are generally very involved in decision making and, in order to be involved, they need honest information.
- Having said that, it is also important to be sensitive to parents’ insecurities, anxieties, and uncertainties, etc.
- Denise and Etienne have been disappointed in the past when Abby could not be successfully extubated.
- I would want to keep this in mind as I discussed her current condition with them.
- I might say something that both provides honest information and maintains a positive, hopeful tone.
- I will also want to ensure that I give Denise and Etienne a chance to express what this experience is like for them.
For example, I might say something like this. “Tell me about how you think Abby is doing”. This open ended question may lead to these parents expressing concerns regarding her labile saturations - particularly when being handled.
So I may respond with, “I also have some concerns about the way Abby is responding to handling today and I think it is important that we pay attention to what she might be trying to tell us before we go ahead and wean her. I’d really like this extubation to be successful and I know you feel the same way. What would you think about us really focusing on Abby’s behavior today? You know her better than I do, so I think it would be really helpful if we did this together and at the end of the day we can talk about our impressions of what might be going on with Abby. How does that plan sound to you?”
28
What are some pulmonary morbidity associated with BPD?
- some infants are discharged home with supplemental oxygen, a tracheostomy and ventilator, or Bilevel/Bipap.
- Infants with BPD have higher rates of re-hospitalizations, with many very low birth weight infants with severe BPD needing re-hospitalization in the first and second year of life
29
What are 3 common reasons for re-hospitalization for infants with BPD?
- reactive airway disease,
- pneumonia,
- respiratory syncytial virus (RSV) infection
- worsening BPD.
30
What 2 airway issues can be long term for infants with BPD?
- Small airway abnormalities
- airway hyperresponsiveness can be long term for many of these infants.
31
What are 2 things that will result from prolonged and repeated intubations?
- Tracheomalacia and bronchomalacia
32
What are 2 airway problems due to mechanical ventilation?
- subglottic stenosis and
- airway granulomas.
33
What is the outcome neurodevelopmentally for VLBW infant with BPD in comparison to VLBW infant without BPD?
- greater fine and gross motor skill impairment
- cognitive function and language delay
34
What may cause Abby’s hematocrit to fall significantly in three days?
This is a tricky question. In other words, we don’t know if her hematocrit has in fact fallen because we don’t know her lab values! I would want to know previous results and look at what her Hct has been doing over time. What’s important here is whether or not there are reasonable reasons that it may have and that Abby’s increased oxygen needs are due to anemia.
For an infant of Abby’s age, there are very few reasons for anemia.
- Internal bleeding is a possible cause. For example, bleeding due to intraventricular hemorrhage, pulmonary hemorrhage, peritoneal hemorrhage, liver or spleen hemorrhage, or gastrointestinal hemorrhage could lead to anemia. Abby is not particularly at risk for any of these problems.
- Another more plausible cause of anemia for Abby is iatrogenic blood loss due to blood sampling. In fact, this is not an unusual problem for infants with health challenges in hospital. Frequent blood sampling can, and does, over time deplete infants’ red blood cells more quickly than they can be replaced. It is important to monitor how much blood we are taking from Abby on our flow sheet.
35
If anemia is not Abby’s problem, what other problems could be causing the responses you are seeing in Abby?
- Worsening BPD,
- pneumonia,
- sepsis,
- influenza, and
- congestive heart failure are all possible causes of Abby’s responses.
36
How would you rule in and/or rule out these problems as likely causes of Abby’s current health status?
- respiratory assessment,
- tracheal aspirate for culture and sensitivity,
- chest x-ray,
- CBC, and
- echocardiogram could all help to rule in/rule out these potential problems.
- However, many of these procedures involve a lot of handling and stress; therefore, the decision to go ahead and complete these assessments should be made cautiously, with consideration of Abby’s need for rest.
37
Is there information normally obtained in a physical assessment of an infant that we don’t have in this case?
- urine output: fluid status
- blood pressure,
- peripheral pulses, and
- perfusion.
All of these pieces of data would help determine the source of Abby’s problem. Urine output, in particular, would tell us about her fluid status. We also don’t yet know her abdominal girth; however, that piece of information may not be particularly helpful in determining why Abby’s oxygen needs are increasing. Having said that, I recall an infant in moderate respiratory distress who, as it turned out, was full of meconium … the infant had a distended abdomen which was putting a lot of pressure on the diaphragm and thorax, making breathing quite difficult. I would also want to know if she had been trialed on noninvasive respiratory support and how she tolerated that.
38
What are 4 cardiovascular involvement accompanying BPD?
- congestive heart failure,
- cyanosis,
- arrhythmias, and
- murmurs
39
What is congestive heart failure (CHF)?
- condition in which the “blood supply to the body is insufficient to meet the metabolic requirements of the organs
- related to the heart’s inability to adequately dispose of venous return, to provide sufficient cardiac output/systemic perfusion to meet the body’s metabolic demands, or a combination of the two
**CHF is a manifestation of an underlying disease or defect, rather than a disease itself
40
What are some causes of CHF?
Increased volume
Obstruction to flow
Ineffective myocardial function
Arrhythmias
Excessive demand for cardiac output
Congenital Heart Defects
Hypoplastic left heart syndrome
Interrupted aortic arch
Coarctation of the aorta
Total anomalous pulmonary venous return with obstruction
Ateriovenous malformation (cranial or hepatic)
Transposition of the great arteries
Patent Ductus Arteriosus (in preterm infants)
Acquired Heart Defects
Myocardial dysfunction
Anemia
Polycythemia or hyperviscosity
Tachyarrhythmias
Myocarditis
41
Why does CHF have effect on the already vulnerable newborn?
- When the right ventricle is unable to pump blood into the pulmonary artery, less blood is oxygenated by the lungs, there is increased pressure in the right atrium and systemic venous circulation, and edema occurs in the extremities and viscera.
- When the left ventricle is unable to pump blood into the systemic circulation, there is increased pressure in the left atrium and pulmonary veins.
- The lungs therefore become congested with blood, causing elevated pulmonary pressures and pulmonary edema.
42
What is the end effects of CHF include?
- decreased cardiac output,
- decreased renal perfusion,
- systemic venous engorgement, and
- pulmonary venous engorgement,
**and their consequent effects.
43
In your own words, explain congestive heart failure.
- Congestive heart failure is an inability of the heart to meet the metabolic demands of the body and/or to manage venous return.
- Typically, CHF is described as being either right or left sided in origin.
- Right sided heart failure results when the right ventricle cannot manage venous return.
- Left sided heart failure results when the left ventricle cannot supply body tissues with oxygen and nutrients.
- While one side of the heart may initially fail, over time, CHF generally progresses to involve both left and right sides of the heart.
44
Explain how each of the following affect cardiac output:
heart rate
preload
afterload
contractility
Cardiac output (CO) is the volume of blood pumped by the heart in one minute. As such, CO is a function of both heart rate and stroke volume. Stroke volume is the volume of blood pumped with each contraction and it is a function of preload, afterload, and contractility.
- an increase in heart rate generally functions to increase cardiac output. However, at very high heart rates stroke volume is decreased because ventricular filling time becomes so short.
- preload is the amount of blood in the ventricles prior to contraction. An increase in preload generally results in an increase in cardiac output.
- afterload is the pressure against which the ventricles must pump; it is measured via the mean arterial pressure. An increase in afterload generally decreases cardiac output.
- contractility is the strength with which the ventricular muscles contract. An increase in contractility results in an increase in cardiac output. Ventricular contractility in infants is generally maximized. In other words, infants’ ventricles are functioning at maximum contractility. Therefore, infants have a limited ability to increase cardiac output by increasing ventricular contractility.
45
Why is tachycardia a common response to hypoxia, decreased perfusion, acidosis, etc.?
- In situations that require an increase in cardiac output, infants respond in the one way that they can: by increasing their heart rates.
*an increase in heart rate generally functions to increase cardiac output
46
Is Abby at risk for CHF? Why or why not?
- Yes, Abby is at risk for CHF.
- Abby and other infants with BPD are at risk for CHF because of right sided heart failure.
- In these infants right sided heart failure occurs because the lungs become congested and edematous, making it difficult for the right ventricle to pump blood through the pulmonary artery.
In this way, right ventricular afterload is increased. Subsequently, blood backs up into the right ventricle, right atrium, inferior and superior vena cava, liver, and eventually forms edema in other body tissues.
- In conjunction with increased right ventricular afterload, left ventricular preload falls.
- Blood that is pooling in the right heart, liver, and tissue edema means that less blood gets through the lungs to the left heart.
- Decreased left ventricular preload means decreased cardiac output.
- This leads to compensatory responses, including fluid retention and decreased urine output.
- Think about what was explained in the previous paragraph. What effect will fluid retention have on right ventricular preload? (It will increase). Will the right ventricle be able to manage this increase in preload? Not likely, given the resistance offered by the lungs to the flow of blood.
47
Is Abby demonstrating any clinical responses which suggest that she may be developing CHF?
Yes.
- Abby’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.
48
What further information would help you rule in and/or rule out CHF as a possible problem for Abby?
It would be helpful
- to know her urine output and
- to assess her peripheral perfusion and pulses.
With CHF, urine output would be deceased, liver may be enlarged, peripheral perfusion would be decreased, and peripheral pulses may be decreased.
- We may also want to consider obtaining a recent chest x-ray as well.
49
What is one of the most effective intervention in prevention of BPD?
- antenatal steroids is one of the most effective interventions
*Prevention of BPD is obviously dependent on the prevention of premature labour and birth.
Preventing preterm birth and appropriate ventilatory management during the neonatal period remain of utmost importance to make an impact on the morbidity and mortality associated with BPD
50
Why is the use of steroids to prevent BPD contraindicated?
- due to the risk of cerebral palsy,
- but that therapy for ventilator dependency or early BPD it may be warranted
51
What is the pros and cons of using dexamethasone to treat BPD?
pro:
- the clinical responses seen in BPD were reduced. The result is increased lung function, thereby decreasing the need for mechanical ventilation and supplemental oxygen.
cons:
- Dexamethasone interferes with normal brain development, specifically neuronal migration, and is implicated with increased rates of cerebral palsy
52
What type of diuretic therapy was used to treat BPD?
- In the past infants with BPD were frequently treated with diuretics such as Lasix (short- term use) and
- thiazides in combination with a potassium sparing diuretic such as spironolactone (long-term use).
53
Why are units choosing not to use diuretics to treat BPD?
- There is limited data that demonstrates significant benefit in routine use of diuretics when outcomes such as mechanical ventilation duration, length of hospitalization, or improved clinical outcomes (less asthma, pulmonary infections) were looked at.
- Furthermore, improvements such as reduction in edema appear to be short term and when weighed against the associated potential side effects (ototoxicity, electrolyte disturbances, metabolic bone disease) many units are choosing not to use diuretics in the routine management of BPD.
54
What are 3 indications for mechanical ventilation?
- hypoxia, hypercapnia, and apnea.
55
Why is mechanical ventilation both a treatment and a factor contributing to the ongoing damage characteristic of BPD.
- 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.
56
What is being suggested in regards to mechanical ventilation and BPD?
- avoid mechanical ventilation whenever possible
- permissive hypercapnia to avoid over ventilation
- avoid hypoventilation
- avoid nosocomial pneumonia
- establish pulse oximeter parameters that permit weaning and avoid hypoxia
- establish gentle ventilation when possible to limit the damage we cause
57
There are several factors which create nutritional challenges for infants with BPD. What are these factors and why do they interfere with providing adequate nutrition for infants with BPD?
- Infants with BPD struggle with nutrition maintenance.
- Although metabolic demands are increased, excessive fluid volumes can potentiate pulmonary edema and lung injury.
- Also, increased work of breathing limits their intake.
- Poor nutrition can lead to abnormal lung development, decreased surfactant administration, increased oxygen toxicity, and further risk for infection (Merenstein and Gardner, 2016).
- Finding a balance between optimizing nutritional needs and restricting fluids can be a challenging part of caring for these infants.
58
What are some of the side effects of diuretic therapy that Abby is at risk for? What are the nursing implications?
- 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.
59
What is the benefits of permissive hypercapnia?
- Permissive hypercapnia, in conjunction with low tidal volumes may decrease volutrauma and protect against detrimental effects of hypocapnia, such as hypoperfusion of the brain and PVL
**Hypercapnia can also cause interventricular hemorrhage and therefore there is a fine balance between over and under treatment.
60
What is family centered care?
- conceptualized as a way of individualizing family participation, requires that Denise and Etienne have some input into decisions that are made about their involvement in Abby’s care.
- Therefore, asking parents about their needs and then listening to them (communicating and collaborating) in a way that reflects an appreciation for who they are as individual people are important cornerstones of family-centered care.
61
What is the relationship between free oxygen radicals and the development of BPD?
- free radicals have a direct toxic effect on pulmonary epithelial cells,
- causing cell membrane injury, enzyme inactivation and structural protein damage.
62
BPD typically alters what blood gas value?
increased pCO2
63
Why is there decreased CO2 removal in BPD?
due to damaged alveoli:
- inflamed,
- scarred,
- atelectatic,
- hyperinflated
64
Sometimes diuretics may be used as a treatment in BPD, are there long term benefits to using this medication?
No,
- reduction in edema appear to be short term
- may cause electrolyte disturbances, ototoxicity & metabolic bone disease
- the risks can be long lasting & there is a lack of evidence for long term benefit.
65
Which electrolyte is commonly low and needs to be replaced?
- sodium (hyponatremia)
66
What is the major side effect of diuretic use?
- electroylte imbalances
67
How is hyponatremia treated, what problem may occur?
- it is treated by adding sodium to either feeds or IV fluid, however, to much supplmental sodium can lead to fluid retention, which is treated by increasing diuretic doses.
- This can lead to hyponatremia ... and so on.
68
What is permissive hypercapnia
- Permissive hypercapnia (PHC) or controlled ventilation is a strategy that minimizes baro/volutrauma by allowing relatively high levels of arterial CO(2), provided the arterial pH does not fall below a preset minimal value.
*the most common conditions where permissive hypercapnia occurs is in infants with bronchopulmonary dysplasia.
- In infants with BPD their blood gases often show a normal pH with a higher than normal pCO2 (compensated respiratory acidosis).
