Preterm infant Flashcards
Definitions:
- Neonate is first how many days after birth?
- Gestational age is the time elapsed between the first day of the last normal what and the day of what? (MP, B)
- Chronological age is the time elapsed after what? (B)
- Post-Conceptual Age is the sum what of what 2 ages?
- 28 days
- menstrual period, birth
- birth
- gestational and chronologic
Definitions:
1. Preterm is birth before how many gestational weeks?
2. “Preemies” should have what 2 ages
to help identify where infant is their maturation of their physiologic processes?
- 37
2. gestational and chronologic age
Classified Weight:
- Low Birth Weight is < how many grams?
- Very Low Birth Weight is < how many grams?
- Extremely Low Birth Weight is < how many grams?
- 2500 grams
- 1500 grams
- 1000 grams
Classified age:
- Mod to Late prematurity is what week range?
- Very Premature is what week range?
- Extremely Premature is what week range?
- 32 to < 37
- 28 to < 32
- < 28
Small airways:
- Increase in resistance to what? (A)
- Resistance to airflow is inversely proportional to the radius of the lumen to the what power for laminar flow to the what power for turbulent flow?
- Turbulent flow is from what to what bronchial division?
- Laminar flow is beyond what bronchial division?
- does the ETT increase or decrease resistance and work of breathing?
- does adding anesthesia increase or decrease WOB?
- anesthesia causes a loss in muscle toning creating a partial what? (O)
- airway
- 4th, 5th
- mouth to 4th bronchial division
- 5th
- increase
- increase
- obstruction
Subglottic Stenosis
- is the narrowing of airway below what? (VC)
- what are 3 causes? (PI, C, TFE)
- does this necessitate a smaller than normal ETT?
- how much smaller?
- vocal cords
- prolonged intubation, congenital, trauma from ETT
- yes
- 0.5
Tracheal Stenosis
- is the narrowing of trachea below what and above what? (VC, C)
- what are 4 causes? (PI, PT, C, T)
- may not need a smaller ETT because the stenosis is what to ETT? (D)
- will there still be an increased resistance and WOB?
- may there be trouble ventilating because of increased resistance?
- vocal cords, carina
- prolonged intubation, prolonged tracheostomy, congenital, trauma
- distal
- yes
- yes
Tracheobronchomalacia
- does the airway collapse during inhalation or exhalation?
- what are 2 things to stent open the airway? (C, P)
- is a higher PEEP usually is needed?
- Mechanical ventilation is better than spontaneous ventilation because it will help do what to the airways and decrease what 2 things? (SO; F, W)
- Should you use larger or smaller I:E ratios to prevent air trapping and hyperinflation?
- exhalation
- CPAP, PEEP
- yes
- stent open; fatigue, work of breathing
- smaller
Respiratory: High Metabolic Rate
- neonates have an increased in what 2 things? (AV, OC)
- what is average neonate alveolar ventilation ml/kg/min?
- what is average adult alveolar ventilation ml/kg/min?
- what is average neonate oxygen consumption ml/kg/min?
- what is average adult oxygen consumption ml/kg/min?
- what can be difficult to maintain normal d/t a neonates alveolar ventilation? (E)
- is the premature oxygen consumption higher or lower than neonates?
- do neonates have a rapid decrease in PaO2?
- alveolar ventilation, oxygen consumption
- 130 ml/kg/min
- 60 ml/kg/min
- 5-8 ml/kg/min
- 2-3 ml/kg/min
- ETCO2
- higher
- yes
Lungs: Pulmonary Gas Exchange
- lungs are immature in what 2 things? (S, F)
- Alveoli are what 3 things? (T, FF, SD)
- do alveoli require greater or lesser pressure to expand?
- production of what by type 2 alveolar pneumocytes is inadequate? (S)
- what gestational week range does surfactant production start?
- surfactant remains inadequate until what week?
- preemies are born with what syndrome? (RDS)
- structure, function
- thick, fluid filled, surfactant deficient
- greater
- surfactant
- 23-24 weeks
- 36 weeks
- respiratory distress syndrome
Immature lungs lead to Respiratory Distress Syndrome (RDS)
- decreases in what 2 things (LV, C)?
- increase intrapulmonary shunting leads to what mismatch and increases the risk of what? (VP, H)
- what are 3 clinical signs? (G, NF, CR)
- anesthesia decrease lung volumes even more which leads to increase in what mismatch and an increase risk of what? (VP, H)
- lung volume, compliance
- VP, hypoxia
- grunting, nasal flaring, chest retractions
- VP, hypoxia
Pulmonary Gas Exchange and Atelectasis
- Large abdomen pushes diaphragm cephalad causes disruption in what and places the what capacity within the expiratory reserve volume? (GE, CC)
- Closing capacity is the volume in the lungs at which the smallest airways do what? (C)
- expiratory reserve volume is the amount of air exhaled during what type of exhale? (F)
- do alveoli close quicker in premature infants?
- what other 3 things can increase abd pressure resulting in the closing capacity to be within the ERV? (OM, SP, SR)
- gas exchange closing capacity
- collapse
- forced
- yes
- overzealous masking, surgical procedure, surgical retraction
- anatomic forces that disrupt gas exchange result in what 2 things? (A, IS)
- what are 4 strategies to help improve a disrupted gas exchange? (MV, P, ES, CSA)
- atelectasis, intrapulmonary shunting
2. mechanical ventilation, PEEP, empty stomach, change surgical position
Mechanical lung injury:
- this can be caused by increased what volumes and frequent collapsing and reopening of what? (EILV, A)
- are micropreemies more susceptible to mechanical lung injuries?
- not having enough what contributes this micropreemies being more susceptible to mechanical lung injuries? (S)
- to prevent lung injuries we use what range of tidal volumes (ml/kg), greater what, sufficient what and permissive what? (RR, P, H)
- what is the permissive range we allow?
- end-inspiratory lung volume, atelectasis
- yes
- surfactant
- 4-6 ml/kg, RR, PEEP, hypercapnia
- 45-55 mmHg
Bronchopulmonary Dysplasia (BPD)
- defined as the need for supplemental oxygen at what postnatal days?
- In BPD, high levels of what and what type of ventilation disrupts maturation of alveoli in preemies? (O, M)
- at what weeks gestation does alveolarization begin?
- are alveoli larger or smaller and more or fewer?
- do alveoli have an increased or decreased SA which increases or decreases O2 requirements?
- 28 days
- oxygen, mechanical
- 36 weeks
- larger, fewer
- decreased SA, increases
Bronchopulmonary Dysplasia (BPD)
- severity is based on what 2 things? (F, P)
- greater risk for perioperative what? (C)
- goal is SpO2 in what % range and PaO2 in what mmHg range?
- FiO2, PPV
- complications
- 90-94%, 50-55 mmHg
How do we prevent BPD?
- what is one thing we can give mom and baby? (AC)
- what is one type of therapy? (EST)
- early and aggressive use of what to prevent ETT?
- what 2 type of meds can we give? (D, B)
- antenatal corticosteroids
- exogenous surfactant therapy
- CPAP
- diuretics, bronchodilators
Hyperoxia
1. what 2 prematurity-related diseases are associated with hyperoxia? (R, B)
2. Oxygen toxicity from hyperoxia leads
to the formation of reactive oxygen what that impair intracellular macromolecules and lead to cell what? (I, D)
3. formation of oxygen free radicals promotes an extensive inflammatory response, leading to what damage and cell what? (T, D)
4. Oxygen-induced vascular endothelial growth factor (VEGF) signals disturbances associated with abnormal what, which it may be detected in what 2 diseases? (A; R, B)
5. oxygen supplementation strategy: recent evidence suggest a graded approach according to what age, meaning increasing O2 saturation targets with increasing what? (G, A)
- retinopathy of prematurity, bronchopulmonary dysplasia
- intermediaries, death
- tissue damage, cell death
- angiogenesis; retinopathy of prematurity, bronchopulmonary dysplasia
- gestational age, age
Respiratory control:
- premature infants have what type of ventilatory response to hypoxia? (B)
- Initially ventilation increases or decreases but after several minutes they do what and then what ensues? (D,A)
- Ventilatory response to what is decreased in micropreemie and what further blunts this response? (C,H)
- does anesthesia increase or decrease the ventilatory responses to hypoxia and hypercapnia?
- biphasic
- increases, decrease, apnea
- CO2, hypoxia
- decrease
Apnea of Prematurity
- occurs commonly in micropreemies and increases or decreases with post-conceptual age?
- is it centrally, obstructively or both?
- central apnea is caused by a decrease in output from where? (RC)
- this decreased output is exacerbated by what 3 things? (H, H, H)
- obstructive apnea occurs because of the incoordination of what muscle? (P)
- is this incoordination made better or worse by anesthesia?
- decreases
- both
- respiratory center
- hypothermia, hypoglycemia, hypocalcemia
- pharyngeal muscle
- worse
Postoperative Apnea
- the incidence of this depends on what 3 things? (PCA, A, ToS)
- which of these is the most significant risk factor?
- occurs in what % of micropreemies?
- increased risk what hct is < what %?
- is it more common after major procedures like laparotomies or peripheral surgical procedures like inguinal hernia repairs?
- usually how many hours after emergence and can be up to how many hours?
- defined as apnea greater than how many seconds or brief apnea with HR less than or equal to how many beats?
- post-conceptual age, anemia, type of surgery
- post-conceptual age
- 50%
- < 30%
- after major
- 1 hour, 48 hours
- > 15 sec, less than or equal to 80
Postoperative Apnea: intraop prevention strategies
- Avoid what type of drugs? (N)
- prevent what 2 things? (H, A)
- can it occur with regional anesthesia?
- what 2 methylxanthines can be give to help prevent? (C, T)
- why is caffeine preferred over theophylline?
- what is the mg/kg IV dose of caffeine?
- caffeine increases the respiratory centers sensitization to what? (H)
- narcotics
- hypovolemia, anemia
- yes
- caffeine, theophylline
- longer half-life
- 10 mg/kg
- hypercarbia
Fetal circulation:
- oxygenated blood from placenta travels via the what vein through the ductus venosus in the what to the what and into which atrium?
- Oxygenated blood from the IVC preferentially enters the which ventricle then goes to which artery?
- oxygen rich blood supplies the what prior to mixing with the oxygen poor blood coming through the what?
- Deoxygenated blood from the superior vena cava enters which ventricle and is pumped to the which artery?
- It then passes through the what to meet the oxygenated blood in the aorta? (DA)
- umbilical vein, liver, inferior vena cava, right atrium
- left ventricle, aorta
- brain, ductus arteriosus
- right ventricle pulmonary artery
- ductus arteriosus
Fetal Circulation to Neonatal Circulation: With first breath…
- lungs do what? (E)
- O2 tension increases or decreases?
- pulmonary vascular resistance increases or decreases?
- blood flows to where? (L)
- does SVR increase or decrease with cord clamping?
- expand
- increases
- decreases
- lungs
- increase
Fetal Circulation to Neonatal Circulation:
- ductus arteriosus functionally closes what hour range after birth and anatomically closes what week range after birth?
- increase in what tension and loss of what from the placenta is thought to close the ductus arteriosus?
- any factors that increase what may revert back to fetal circulation? (P)
- what are 4 things that can increase PVR? (H, H, H, A)
- what shunt do these cause?
- 12-24 hours; 2-3 weeks
- O2 tension, prostaglandins
- pulmonary vascular resistance
- hypoxia, hypercarbia, acidosis, hypothermia
- right to left
Failure of Patent ductus arteriosus closure:
- 1 in how many thousands of full term births?
- what % of extremely low-birth-weight infants?
- immature smooth muscle cells fail to do what? (C)
- immature lungs can’t metabolize what? (P)
- 1/2000
- 60%
- constrict
- prostaglandins
PDA left to right shunt:
- increase or decrease in SVR and increase or decrease in PVR at birth causes this?
- results in excess BF to where as well as what 2 types of failure?
- does the pulse pressure widen or narrow?
- is there a risk for coronary ischemia?
- what is restricted and what type of meds are given to offload lungs? (F, D)
- increase, decrease
- lungs; congestive heart failure, respiratory failure
- widen
- yes
- fluids, diuretics
PDA right to left shunt:
- occurs in neonates with persistent what and what syndrome?
- this type of shunt results in what? (C)
- flow ends up going out what and not to where?
- persistent pulmonary hypertension, respiratory distress syndrome
- cyanosis
- patent ductus arteriosus, lungs
PDA and NSAIDs:
- what 2 NSAIDs are given? (I, I)
- these meds inhibit the production of what by decrease the activity of cyclooxygenase?
- what % closure rate?
- ibuprofen, indomethacin
- prostaglandins
- 80%
what 6 things increase pulmonary vascular resistance? (H, H, A, A, P, P)
- hypercarbia
- hypoxia
- acidosis
- atelectasis
- PPV
- PEEP
what 4 things decrease pulmonary vascular resistance? (N, O, A, H)
- nitric oxide
- oxygen
- alkalosis
- hypocarbia
Persistent Pulmonary Hypertension (PPHN)
- occurs in how many births out of 1000?
- PPHN is diagnosed when what-to-what shunting of blood occurs through a PDA and/or PFO in the absence of what disease?
- this shunt occurs because what vascular resistance fails to decrease at birth? (PVR)
- is the etiology understood?
- Suspected in hypoxic neonates with no increase in preductal or postductal O2 sat despite being on vent and high FiO2?
- what limb/limbs for preductal?
- what limb/limbs for postductal?
- 2/1000 births
- right to left shunt; congenital heart disease
- pulmonary vascular resistance
- no
- postductal
- R arm
- L arm and either leg
Persistent Pulmonary Hypertension (PPHN)
- Greater preductal saturation or post ductal saturation supports diagnosis because all the oxygenated blood is going through PDA?
- timely diagnosis and treatment is imperative to prevent what 4 things? (ND, CP, D, B)
- do Premature infants tend to have worse outcomes requiring Extracorporeal membrane oxygenation (ECMO) compared to term infants?
- preductal saturation
- neurodevelopmental delay, cerebral palsy, deafness, blindness
- yes
Persistent Pulmonary Hypertension Treatment:
- maintain what pressure adequately? (SBP)
- optimize lung management by preventing what? (O)
- avoid what which will increase PVR? (A)
- maximize the delivery of what? (O)
- what invasive technique? (E)
- inhaled what med? (N)
- systemic blood pressure
- overdistention
- acidosis
- oxygen
- ECMO
- nitric oxide
Pulm HTN and iNO
- selectively what vasodilator by diffusing into what type of muscle and increasing what which causes vascular relaxation? (P, SM, cG)
- iNO decreases what 2 things and increases what thing? (P, RtLS; SO)
- does iNO decrease the need for ECMO?
- do all infants respond to iNO?
- what is the initial dose of iNO in ppm?
- pulmonary vasodilator, smooth muscle, cGMP
- PVR, R to L shunt; systemic O2
- yes
- no
- 20 ppm
Pulmonary HTN and iNO
- iNO oxidizes hemoglobin into what making it something to monitor? (M)
- slowly wean iNO to avoid rebound what? (PH)
- what med type can be added during weaning? (PI)
- name 2 of these meds (S, M)
- both of these meds increase what leading to smooth muscle vascular relaxation? (cG)
- is sildenafil PDE 3 or PDE 5?
- is milrinone PDE 3 or PDE 5?
- methemoglobin
- pulmonary htn
- phosphodiesterase inhibitors
- sildenafil, milrinone
- cGMP
- PDE 5
- PDE 3
Cardiovascular:
- fetal hearts have more what type of tissue? (C)
- are the contractile elements more or less organized?
- increased or decreased dependents on extracellular Ca?
- high or low resting HR?
- frank-starling more or less flat because of decreased ventricular compliance?
- connective tissue
- less
- increased
- high
- more flat
Cardiovascular:
- more or less sensitive to catecholamines?
- Greater or lesser blood volume per kilogram but larger or smaller absolute blood volume?
- Small amount of EBL can cause what 3 things? (H, H, S)
- is autoregulation developed or not well developed?
- May the HR not increase in response to hypovolemia?
- can perfusion to brain decrease with very little EBL?
- are micropreemies more prone to C/V collapse during anesthesia and surgery?
- less sensitive
- greater volume per kg; smaller absolute
- hypovolemia, hypotension, shock
- not well developed
- yes
- yes
- yes
Immature Brain
- is CNS fully developed at birth?
- what week range does preoligodendrocytes and astrocytes multiply and cortical and subcortical structures develop?
- During this week range, what white matter is most susceptible to injury? (P)
- this white matter is termed watershed region because it is susceptible to poor what? (P)
- this white matter is susceptible to injury when what is decreased and during what other states? (DCO, H, H, H)
- is a baby born at 30 weeks still susceptible to these injuries?
- no
- 24-27 weeks
- periventricular
- perfusion
- decreased cardiac output, hypotension, hypoxemia, hypercarbia
- yes
Pain perception
- First trimester: withdrawal reflex to what type of stimuli? (N)
- Second trimester: transmission of what type of stimuli? (N)
- Third trimester: pathways between what and what cortex are functional? (T, SC)
- should we still treat pain in micropreemies?
- non-noxious stimuli
- noxious
- thalamus, somatosensory cortex
- yes
Glucose and brain
1. do neonates require a lot of glucose?
2. in regards to ischemic events, is hyperglycemia protective or harmful in neonates?
3. can mild hypoglycemia cause brain damage in preterm infants?
4. Micropreemie is more or less at risk because they have more or less glucose stores and consume more or less glucose?
5. Mild or moderate hyperglycemia during surgery is best managed by reducing the rate of infusion of and not
administering what? (DCS, I)
- yes
- protective
- yes
- more, less, more
- dextrose-containing solution, insulin
Complications of prematurity:
- what are 5 long term disabilities? (CP, CD, BA, HI, VI)
- ELBW only what % were normal developed at age 5 and what % were exhibited major disabilities?
- Most common abnormality is problems in the periventricular cerebral white matter seen on what scan?
- on the scan, Increased water content, and delayed white matter maturation suggest what type of injury? (IR)
- cerebral palsy, cognitive deficits, behavioral abnormalities, hearing impairments, visual impairments
- 25%, 20%
- MRI
- ischemia-reperfusion
Intraventricular Hemorrhage (IVH)
- one in how many micropreemies have IVH?
- associations between IVH and fluctuations in what?
- what scan is used to determine severity?
- 1/3
- BP
- ultrasound
IVH grading:
- Grade 1- hemorrhage limited to what matrix? (G)
- Grade 2- extending into the what system? (V)
- Grade 3- extending into the ventricular system with dilation of what? (V)
- Grade 4- extending into brain what? (P)
- Long term neurocognitive sequelae associated with what grades?
- germinal matrix
- ventricular system
- ventricles
- parenchyma
- grade 3 and 4