Neonatal Emergencies Flashcards
1
Q
The left shift on the oxyhemoglobin curve for neonates is primarily due to what factor?
A
- No 2,3 DPG
2
Q
What is the oxygen consumption rate of the Neonate?
A
- 4-7 mL/kg/min
3
Q
In periods of hypoventilation, what factor in the neonatal physiology leads to a decrease in blood oxygen levels?
A
- High rate of 02 consumption
4
Q
Body composition of water of a fetus?
A
- 90%
5
Q
Body composition of water of a preterm infant?
A
- 80%
6
Q
Body composition of water of a full-term infant?
A
- 70%
7
Q
Body composition of water of a 6-12 month old?
A
- 60%
8
Q
Factors that have implications for drug dosing in infants?
A
- High relative body water composition
- Increased volume of distribution
- Decreased body fat percentage
- Decreased muscle
9
Q
What effect does anesthesia induction have on infants?
A
- Higher incidence of cardiovascular instability and cardiac arrest
10
Q
What two classes of medications do neonates have an increased sensitivity?
A
- Barbiturates
- Morphine
11
Q
T/F, Neonates have a decreased response to pain relative to that of adults.
A
- False
- Physiologic response to pain is similar to adults
12
Q
Because neonates are sensitive to barbiturates and morphine, what is a good alternative?
A
- Remifentanil
13
Q
Relative to their body size, what is the proportion of neonatal lung volumes?
A
- Disproportionately small
14
Q
What effect does the high metabolic rate and minute ventilation have in the oxygen consumption of neonates?
A
- 02 consumption per body weight is twice as high that of adults
15
Q
What two factors put the neonate at high risk for desaturation?
A
- Less reserve lung volumes
- Less gas excahnge surface area
16
Q
The increased Cardiac Output in the neonate has what effect on volatile anesthetic delivery?
A
- Increased delivery to vessel rich group
- Partial pressure of VAA in venous blood rapidly approaches that of alveoli and speeds FA/FI. “Whisking away”
17
Q
What effect do more soluble VAA have on anesthetic delivery?
A
- Faster rate of rise of FA/FI
- Halothane, Isoflurane
18
Q
What effect do less soluble VAA have on anesthetic delivery?
A
- No change from adults
- Sevoflurane, Desflurane
19
Q
- What effect does a right/left shunt have on VAA delivery?
A
- Slows rate of rise of FA/FI, prolonged induction
- More “whisking away”
20
Q
How are less soluble volatile agents effected in a right to left shunt?
A
- More prolonged induction compared to more soluble agents
- Soluble agents are already “whisked away” more in the alveoli. Therefore less soluble agents are more affected by the shunt.
21
Q
What type of fluids are best to use with neonates
A
- Non-glucose containing (plasmalyte, LR)
Unless glucose is indicated
22
Q
What is the normal hemoglobin range at birth for a neonate?
A
- 14-20 g/dL
23
Q
What is the hematologic reason for increased risk of infection in neonates?
A
- Immature leukocyte function
24
Q
What hematologic reasons puts the neonate at risk for hemorrhage?
A
- Immature liver causes low levels of Vitamin-K dependent factors
- All infants are administered Vitamin K
25
Which part of the Central Nervous System is dominant in utero?
- Parasympathetic Nervous System
26
What is the premature heart rate?
- 120-170 bpm
27
What is the mean heart rate at birth?
- 12o bpm
28
What is the normal heart rate range at one month?
- 100-160 bpm
29
What is the mean systolic blood pressure at birth?
- 65 mmHg
- Except in coarctation of the aorta, there is increased blood pressure in the upper extremities and decreased in the lower extremities
30
How does the neonate control cardiac output?
- Neonates are highly dependent on HR to maintain CO
| - CO= 200 mL/kg/min
31
What are the factors that contribute to the rapid decompensation of the cardiac output of the neonate?
- Low compliance of ventricles
- Sensitivity to drugs that produce negative inotropic and chronotropic drugs
- Parasympathetic Nervous System is fully mature at birth
- Sympathetic Nervous System is immature at birth
32
What are the major physiologic implications of the neonatal renal system?
- Decreased ability to excrete saline
- Decreased ability to excrete water loads
- Decreased ability to excrete and drugs
- Normal renal function occurs at 6 months, reaches adult levels at 2 years old
- GFR is 15-30% at birth, reaches adult values by end of first year
33
Why does physiologic acidemia occur at birth?
- Low renal tubular threshold for bicarbonate (reduced acid buffer)
- Low level of production and excretion of urea
34
What is the major carrier protein in the fetus?
- Alpha fetoprotein
35
Albumin production begins in the first 3-4 months of gestation and levels are normal at birth. However, what albumin-dependent blood components remain low for the first few weeks of life?
- Clotting factors
36
What is a consequence of the immature liver in neonates?
- Impaired conjugation
- Increased bilirubin
- Drug metabolism is not effective in first few weeks of life
37
What are the primary causes of reflux in the neonate?
- Absent peristaltic waves in the lower esophageal sphincter
- Immature pharyngoesophageal sphincter
- LES becomes normal after 3-6 weeks
- 40% incidence of regurgitation in newborns
38
What GI condition is associated with neonatal apnea and bradycardia?
- GERD
| - Peds should be induced with RSI
39
What three factors contribute to rapid heat loss to the environment in the neonate?
- Thin skin
- High surface area relative to weight
- low fat content
40
What condition delays awakening from anesthesia, causes cardiac irritability, respiratory depression, increased pulmonary resistance, and altered drug response?
- Hypothermia
- Please note that pulmonary resistance, cardiac irritability, and respiratory depression are all factors associated with persistent fetal circulation
41
Compared to adults, what are the anatomical differences of the neonatal tongue?
- Larger than in adults
- Difficulty viewing larynx
- Difficult to stabilize tongue with larygoscope
42
Describe Poiseuille's Law.
- Resistance is inversely proportional to the 4th power of the radius
- Increased resistance in small airways
43
What is airway resistance in neonates? In adults? And what anatomical region is responsible for increased resistance?
- 19-28 cmH20/L/sec
- 2 cmH20/L/sec
- trachea-12th bronchial generation
- Resistance is normal at five years old
44
What is an anesthesia-related concern int he immature trachea?
- Tracheal collapse can occur during inspiration or expiration
- Airways may collapse without PEEP during PPV
45
What are the differences between the neonatal and the adult trachea?
- More cephalad in the neck
- @ level C3-C4 (C4-C5 in adults)
- Hyoid bone is at C2-C3
- Trachea is more anterior
46
Describe the neonatal epiglottis
- Narrow
- Omega-shaped (U-shaped)
- More difficult to lift with a laryngoscope
- Miller-0 or Miller-1 common in pediatrics
47
Describe the neonatal subglottic region
- The narrowest part of the larynx is the cricoid cartilage
- Funnel-shaped
- Edema of tracheal mucosa reduces luminal diameter and increases airway resistance (Poiseuille's Law)
- Do not inflate cuff or use uncuffed ETT
48
What is the consequence of the narrow airways of the neonate?
- Obligate mouth breathers
49
What are some of the factors that will narrow the neonatal airway and its' consequence?
- Long ETT of small diameter?
- Obstructed ETT
- Physically narrowed ETT
- Will increase work of breathing
50
Neonatal airways are more compressible because...?
- Their trachea is more complaint
51
Where are the areas of highest airway resistance in the neonate?
- Bronchial and small airways
- Remember, trachea-12th bronchial generation
- Small airways account for most of the work of breathing
52
What is the appropriate blade for a pretermers and neonates?
- MIL-0
53
What is the appropriate blade for neonates up to two-year-olds?
- MIL-1
54
When an ETT that is too large for the airway is used, there are changes in position during the case. multiple intubation attempts, and surgeries longer than one hour put the neonate at risk for what condition?
- Post-intubation croup
55
What is the treatment for post-intubation croup?
- Humidified mist
- Nebulized Epinephrine
- Dexamethasone
56
Describe laryngotracheal stenosis of the neonate
- Cause by ischemic injury secondary to lateral wall pressure from the ETT (Think of it as a decubitus ulcer in the trachea)
- Scar tissue narrows the airway
- 90% of acquired subglottic stenosis is caused by prolonged intubation
57
What is the best monitor to assess changes in breath and heart tones?
- Precordial stethoscope
58
What are the important neonatal considerations regarding blood pressure cuffs?
- Have appropirately-sized cuff
| - Do not cycle more than every 3-4 minutes
59
What are the important neonatal considerations regarding arterial line placement?
- 22 or 24 Gauge
| - Placed on radial, dorsalis pedis, or posterior tibial arteries
60
What are important considerations with 02 saturation monitoring of the neonate?
- Maintain preductal (Right hand) saturation between 93-95%
- Risk of retinopathy of prematurity
- Probability of blood shunting through patent ductus arteriosus
- Post-ductal is monitored from the lower extremities
61
What are indications for a CVP in neonates?
- Blood administration
- TPN
- Monitoring central venous pressures
62
What are the three types of apnea possible with neonates?
- Central apnea
- Obstructive apnea
- Mixed apnea
63
What are the characteristics that make a neonate more prone to apnea?
- Prematurity
- History of apnea
- Chronic lung disease
64
What are the post-anesthesia care recommendations for preterm infants?
- Monitoring for 12 apnea-free hours post-anesthesia
- 24-hour hospitalization after anesthesia
- Most common in preterm infants younger than 60-weeks postconceptional age.
65
What are the important anesthesia considerations with SIDS?
- Can occur with infants between 1-12 months
- Increased risk with; prematurity, history of bronchopulmonary dysplasia, presence of infant apnea syndrome (not apnea from prematurity)
- No evidence that general anesthesia triggers SIDS
66
Describe Kernicterus
- Increased bilirubin affecting the CNS
- Immature blood-brain barrier
- Disruption of blood-brain barrier
- S/S- hypertonicity, opisthotonos (extreme hyperextension of head/neck/spine), and spasticity
67
What are the anesthetic implications of kernicterus?
- GERD
- Cerebral palsy
- Mental retardation
68
Why do infants develop RDS?
- Respiratory Distress Syndrome
- Hyaline Membrane Disease
- Surfactant deficiency
- Surfactant production occurs majorly after 32-weeks post-conception
69
What are the CXR findings with RDS?
- Loss of lung volume
| - Atelectasis
70
What are the pathophysiologic implications of RDS?
- Grunting
- Nasal flaring
- Chest retractions
- Shunting
- Systemic hypoxemia
71
Describe the anesthetic implications of RDS
- Maintain Pa02
- Be wary of anesthetic agents
- Preductal monitoring
- PEEP
- Be wary of barotrauma
- Maintain HCT
- Be wary of fluids
72
Describe Bronchopulmonary Dysplasia
- Common with a history of RDS
- Reactive airway with increased resistance
- Decreased pulmonary compliance
- Increased V/Q mismatch
- Decreased oxygenation
- Tachypnea
- Symptoms decrease w/ age
73
How is BPD diagnosed?
- Abnormal CXR of the infant requiring high levels of 02 therapy before 36-weeks postconceptual age
- Chronic lung disease seen in premature infants
74
What is the treatment for infants with BPD?
- Prolonged expiratory time to avoid air trapping
- Bronchodilators to reduce airway resistance
- Diuretics (keep lungs dry)
- Corticosteroids (reduce bronchiole inflammation)
75
What is unique about ETC02 monitoring in the neonate?
- May UNDERestimate the C02 levels in exhaled gases
| - May use special ETT with C02 sampling port
76
What is a unique consideration in mechanical ventilation of the neonate?
- May need advanced ventilator
| - High-frequency oscillation
77
What are unique considerations of intra-op monitoring of urine output of the neonate?
- U/O is 0.5-2mL/kg per hour
| - Difficult to assess in an infant weighing less than 1 kg
78
What is the cause of choanal atresia/stenosis?
- Failure of the bone in the nasopharynx to regress during development (may cause an obstruction)
- May manifest as cyanosis at rest, resolves with crying or placement of an oral airway
- Often associated with a constellation of other congenital abnormalities
79
When caring for the patient with choanal atresia, what is the single most important intervention the anesthesia provider should perform?
- PLACE AN ORAL AIRWAY
80
What is a laryngeal abnormality that creates an airway emergency at the time of birth?
- Webs
- A thin layer of tissue narrowing the tracheal lumen
- Will need a tracheostomy
81
Describe anesthesia induction in the patient with Congenital Subglottic Stenosis
- INHALATION WITH A FACE MASK WHILE MAINTAINING SPONTANEOUS VENTILATION
- Place ETT small enough to pass through the level of the obstruction
- The severity of condition dependent on the degree of airway occlusion
- Tracheostomy and dilation attempts may be necessary in severe cases
82
What are the signs and symptoms of Esophageal Atresia?
- (DOC)
- Life-threatening gastric DISTENTION that may require one-lung ventilation until it is decompressed
- ORAL catheter cannot be passed into the stomach
- CYANOSIS and coughing during oral feeding
83
Describe the treatment of esophageal atresia
- Ligation of defect and anastomosis of esophageal segments
| - Gastrostomy under LA in preemies with anomalies with delayed repair when they are stable
84
What is the relationship between Esophageal Atresia and Tracheoesophageal Fistula
- 20% of EA and TEF have co-existing disease and cardiac anomalies
- (VATER-L)
- Vertebral Defects
- Anal atresia
- TEF
- Esophageal atresia
- Renal anomalies
- Limb anomalies
85
S/S of EA and TEF?
- (RED-R)
- Regurgitation of feeds
- Excessive oral secretions
- Difficulties swallowing
- Respiratory distress exacerbated by feedings
86
How is EA w/ TEF diagnosed?
- Inability to pass an OGT into stomach or by radiographic studies
- KUB will show bowel gas
87
What are some preoperative interventions used to optimize the patient w/ Tracheal Esophageal Fistula
- Avoid feedings
- Upright position, minimize reflux
- Intermittent suctioning of the upper pouch
- Administration of antibiotics to treat sepsis or aspiration pneumonia
88
What are critical monitoring modalities indicated for surgery on the patient w/ TEF?
- Arterial Line
| - Pre- and Post-ductal 02 saturation (Right-hand, one foot) if Right to Left shunting is present
89
What is the surgical approach to repairing TEF?
- Right thoracotomy
- If repair is delayed the fistula is ligated and a gastrostomy tube is inserted
- Definitive repair is delayed until the child is 3-6 months (this approach improves outcomes)
90
What is the anesthetic technique for a case involving Tracheal Esophageal Fistula?
- Awake intubation
- FENTANYL OR MORPHINE FOR INTUBATION
- Secure tip of ETT distal to the fistula
- Movement of ETT may lead to the inability to ventilate
91
What are the anesthetic implications associated with Esophageal Atresia and Tracheal Esophageal Fistula?
- (TREAD)
- TRACHEAL Collapse
- REFLUX and Pneumonitis (may present)
- EXCESSIVE Airway Pressures (avoid)
- AWAKE Extubation
- DECOMPRESS Upper Pouch
92
What are the typical S/S associated with Congenital Diaphragmatic Hernia?
- POLYHYDRAMNIOS (Excess Amniotic Fluid)
- Intrathoracic Gastric Bubble
- Mediastinal shift away from defect
- Barrel-chest
- SURGICAL EMERGENCY
93
Why is persistent fetal circulation likely with Congenital Diaphragmatic Hernia?
- Hypoxia
- Elevated pulmonary vascular resistance
- (High perioperative mortality, left-sided most common, pulmonary hypoplasia, bowel sounds on chest auscultation, evident on CXR)
94
What are some of the S/S of Congenital Diaphragmatic Hernia?
- The hallmark is the abnormal compression of pulmonary structures
- Lung growth is severely retarded
- Pulmonary hypertension
- Right-to-left shunting via the PFO and PDA causes severe HYPOXEMIA
- Caval compression by intrathoracic contents reduces preload and CO
95
What are the congenital anomalies associated with Congenital Diaphragmatic Hernia?
- Cardiac
- GI
- GU
- Skeletal
- Neural
- Trisomy-21
96
What is the classic triad associated with Congenital Diaphragmatic Hernia?
- Cyanosis
- Dyspnea
- Dextrocardia (flipped heart)
97
What are the assessment findings that will be apparent with Congenital Diaphragmatic Hernia?
- Scaphoid Abdomen
- Bulging chest
- Decreased breath sounds
- Distant or right-placed heart sounds
- Bowel sounds in the chest
98
What are the anesthetic implications in the treatment of the patient with Congenital Diaphragmatic Hernia
- Preoxygenation with AWAKE intubation
- Decompression of stomach
- Watch for persistent fetal circulation (monitor right arm)
- Avoid nitrous oxide
- Do no re-expand hypoplastic lung (barotrauma)
- Beware abdominal closure, contents may not fit the under-developed cavity
- Requires prolonged intubation
99
Describe initial management of the patient w/ Congenital Diaphragmatic Hernia
- Improve oxygenation and ventilation
- Airway control is a priority
- Do no mask ventilate infant (more air in the bowel, more intrathoracic pressure)
- Decompress contents w/ NGT after intubation
- ABG
- CXR
- ECHO
- Cranial U/S
- IV Access
- Arterial Line
100
What are the unique consideration when ventilating the patient w/ Congenital Diaphragmatic Hernia?
- The goal is to avoid barotrauma and increased PVR
- Vent. settings should allow rapid low tidal volumes and limit PIP to avoid barotrauma (and/or a little PEEP)
- Deliberate alkalosis increases pulmonary blood flow
101
Why can't you use N20 during anesthesia care of the patient w/ Congenital Diaphragmatic Hernia?
- Limits oxygen Fi02
| - Intestinal diffusion may worsen lung compression
102
What are the two types of GI-associated surgical emergencies?
- Lesions that are obstructive
| - Conditions that compromise blood suppy
103
What S/S may be seen in infants with obstructive GI lesions?
- May present w/ vomiting, abdominal distention, late passage of meconium
- Treatment is to establish euvolemia and a steady metabolic state prior to surgery if not an emergency
104
Describe the surgical implications of infants presenting with obstructive GI lesions
- Awake intubation if problems are anticipated, RSI if airway is normal
- Ketamine if surgery is an emergency and volume status is tenuous
- GETA w/ VAA or Opioid technique and muscle relaxant
- AVOID N20
- Blend Air/02
105
What are the anesthetic implications of the patient w/ emergency GI issues that compromise blood supply?
- Present w/ abdominal distention, bloody stools, vomiting, hypotension, metabolic abnormalities, anemia, thrombocytopenia
- Emergency surgery required to remove necrotic tissue, close perforations, establish perfusion to intestines
106
Describe the anesthetic implications in treating the infant w/ obstructive GI lesions
- Adequate IV access
- T&C, blood products must be immediately available
- Arterial line
- Optimize volume status
- Dopamine to increase perfusion to the gut
107
Describe pyloric stenosis and is it a surgical emergency?
- It is not a surgical emergency
- Hallmark is hypertrophy of the muscularis layer of the pylorus palpated as olive-shaped mass in the middle and RUQ
- Non-bilious vomiting in 2nd-8th week of life
- Renal response to vomiting consists of:
- sodium and potassium loss from alkaline urine to maintain serum pH
- As electrolytes deplete, kidneys secrete acidic urine , worsening metabolic alkalosis
- Further fluid loss results in prerenal azotemia and metabolic acidosis
108
Describe the anesthetic implications of treating the patient with pyloric stenosis
- Empty stomach w/ OFT PRIOR to induction (unique)
- Awake intubation or RSI (PULMONARY ASPIRATION IS A RISK)
- Maintenance w/ VAA or balanced anesthesia technique
- Extubation w/ infant fully awake
- LA at incision site for analgesia
- Monitor for apnea
- Caution w/ opioids
- Procedure < 30 min.
109
What are the unique considerations in the postoperative care of the patient with pyloric stenosis?
- Extubate w/ infant fully awake
- Possible ventilatory depression (CSF alkalosis and intraoperative hyperventilation of infant's lungs)
- Must have acceptable patterns of ventilation
110
What are the critical anesthetic considerations associated with Necrotizing Enterocolitis (NEC)?
- Considered a surgical emergency
- Affects infants younger than 32 weeks of gestational age
- Necrosis and increased mucosal permeability related to sepsis
- Sepsis (DIC, acidosis, perf. bowel, short bowel syndrome)
- Decreased mesenteric blood flow, iscemia
- Most commonly in (ileocolic region, can involve large AND small intestine)
- Bacterial growth causes pneumatosis intestinalis
- AWAKE INTUBATION
111
What are the S/S associated with NEC?
- Poor feedings
- Vomiting
- Malabsorption of feedings
- Lethargy
- Hyperglycemia
- Bloody stools
- Abdominal distention
- Retained gastric secretions
- Adynamic ileus
- pneumoperitoneum
112
What are the critical preoperative assessment findings associated w/ NEC?
- Evaluate and correct respiratory, circulatory, metabolic, and hematologic disorders
- Check labs (ABG, Glucose, Electrolytes, H/H, coags)
- 3rd-space fluid losses (Give crystalloids or colloids)
- Increasing respiratory support as abdominal distention, and/or metabolic/respiratory acidosis worsens
- Consider NICU ventilation/Manual ventilation/anesthesia machine
113
What are the indications for surgery related to NEC?
- Bowel perforation
- Peritonitis
- Air in portal system
- Bowel wall edema
- Ascites
- Deteriorating hemodynamic status
- Treat sepsis (Fluids, inotropes, vasopressors)
114
What are the surgery and anesthetic considerations associated w/ NEC?
- Coagulopathies, have products available (preemie pack consists of irradiated blood)
- RSI if no airway issues, Awake intubation otherwise (usually intubated in NICU, maintain sp02 85-90%)
- Septic and volume depleted, no VAA (high opioid and muscle relaxant), NO N20
- High volume requirements (albumin 1-2 time blood volume)
- Inotropes
- Monitor glucose
- Control hypotermia
- Remain intubated post-op
115
Describe an Omphalocele
- Hernial sac at the base of the umbilicus
- Occurs predominantly in males
- Associated w/ other congenital defects
- 30% mortality rate
- Bowel usually functional
- Medical emergency, not surical emergency
116
Describe a Gastroschisis
- Lateral to the umbilicus
- No hernia sac
- Rarely occurs w/ other congenital defects
- Medical emergency not surgical emergency
117
What are the hallmarks of treatment of Omphalocele and Gastroschisis?
- Reduction of fluid loss from exposed viscera, minimize heat loss, minimize infection (sterile silo)
- Fluid resuscitation is major part of treatment
- LR BOLUSES, 5% ALBUMIN @ 3-4 TIMES USUAL MAINTENANCE (150-300 ML/KG/DAY)
118
What are the critical anesthetic implications in treating the neonate w/ an omphalocele or gastroschisis?
- Awake intubation or RSI (ventilation w/ 02/air and low VAA)
- ASSESS INTRAGASTRIC PRESSURES AND CVP
- Aspirate stomach contents
- Muscle relaxation
- Staged closure may be necessary
- NO N20
119
What are the abnormalities associated w/ Prune Belly Syndrome?
- 97% of cases occurs in males
- TOF, VSD
- Abdominal and Lung abnormalities
- Congenital hip dislocation
- Cryptorchidism (undescended testicles)
- Club feet
- GU tract abnormalities
120
Describe the anesthetic management of the patient w/ Prune-Belly?
- Chronic aspiration risk
- Limited coughing ability
- ETT necessary
- Controlled ventilation
- Minimize muscle relaxants, maximizes extubation possibility
121
What are the complications that come from abnormal vascular development in the retina?
- Retinopathy of prematurity
- Risk of vasoconstriction and hemorrhage
- Creates scars
- Retinal detachment and blindness occur as scars retract
