Pediatrics II Flashcards
Premature Infant
Anesthetic Considerations
Already intubated ICU transport
Uncuffed/cuffed ETTs
Difficult intubation - subglottic stenosis
Difficult ventilation - poor compliance; avoid barotrauma & excessive oxygen
Position change → check ETT
NSAIDs contraindicated
Consider IV caffeine to prevent apneas
Why are NSAIDs contraindicated in premature infants?
Immature renal system
Premature PDA closure
Avoid IV Ketorolac until 6mos-1yo
What effect do inhalational anesthetics have on premature infants?
More susceptible to the cardio-depressant effects
Neonatal heart dependent on plasma Ca2+
Neonate MAC
Sevo 3.2% (2)
Iso 1.6% (1.2)
Des 9.2% (6)
Infant MAC
Sevo 3.2% (2)
Iso 1.8% (1.2)
Des 10% (6)
Child MAC
Sevo 2.5% (2)
Iso 1.4% (1.2)
Des 8.2% (6)
Fentanyl
↑Vd
↓elimination 1/2 life
Premature infants 6-32hrs
Children & adults 2-3hrs
Propofol
Protracted hypotension & ↓CO
↓dosages
Infusions rarely used long-term
Midazolam
↓clearance especially w/ impaired liver function
Dexmedetomidine
Propofol pre-treatment to alleviate neuronal cytotoxicity
HbF
Fetal hemoglobin
Main O2 transport protein in fetus during development in-utero & persists until 6mos
↑oxygen binding affinity
LEFT SHIFT
Carries 20-50% more oxygen than maternal Hgb
Physiologic Anemia
Transition HbF → HbA
Full-term infants 10-11g/dL
↓erythropoiesis & shorter RBC lifespan
Premature infants 7-9g/dL
Consider transfusion when Hct <30%
3mos Hgb level stabilizes to 11-12g/dL until 2yo
PDA
L → R shunt
Excessive pulmonary blood flow
CHF & respiratory failure
R → L shunt
Pulmonary HTN → cyanosis
PDA Ligation
Medical: - Admin COX inhibitor - Indomethacin (Indocin) or Ibuprofen Surgical: - L thoracotomy w/ lung retraction - Clip or transcatheter closure "plug"
PDA Ligation
Preop
Assess arterial pressure ↓diastolic (widened pulse pressure), HR, arterial blood gas, ventilator setting, FiO2
PRBCs on hold
Antibiotics - endocarditis risk
PDA Ligation
Intraop
Blood pressure monitoring on R arm (reflects cerebral perfusion & pre-ductal)
Pox pre & post-ductal
ETCO2 monitoring
Minimal ETT leak (lung retraction ↑ventilator inspiratory pressures & FiO2)
Opioids, amnesia, & muscle relaxation
Intercostal nerve block placed by surgeon at surgery completion
PDA Ligation
Complications
Inadvertent aorta or pulmonary artery ligation or laceration
Aorta clamp → Pox loss signal LE
Pulmonary artery clamp ↓oxygen saturation & ETCO2
NEC
Necrotizing enterocolitis
Low birth weight infants mortality up to 50%
85% cases infants < 1,500g birth weight
Morbidity associated w/ short bowel syndrome, sepsis, & adhesions
Intestinal mucosal injury 2° to bowel ischemia & ulceration
NEC S/S
Early signs - abdominal distension, bloody diarrhea, temperature instability, & lethargy
Metabolic & hematologic abnormalities - hyperkalemia, hyponatremia, metabolic acidosis, hypo/hyperglycemia, coagulopathy, DIC, anemia
Often already intubated d/t abdominal distension w/ OG/NG tube suctioning & hemodynamic instability
NEC Treatment
1° NICU medical management
Peritoneal drainage often performed at bedside
Bowel perforation & free air present in abdominal cavity → urgent/emergent surgery
Exploratory laparotomy w/ necrotic bowel resection
Risk life-threatening sepsis after perforation d/t bacteria entering bloodstream
NEC
Anesthetic Considerations
Aspiration risk → RSI or awake intubation
Inhalational agents poorly tolerated
- Consider narcotic technique w/ muscle relaxation to maintain hemodynamic stability
Avoid nitrous oxide
PIV x2
A-line or UAC
Fluid & blood loss
- Admin PRBCs (10-15mL/kg), FFP (10-15mL/kg), platelets
Correct electrolytes
Monitor glucose
Allowable Blood Loss
[EBV x (starting Hct - allowable Hct)] / starting Hct
25%
Relatively small amount blood loss → severe hypovolemia
NEC
Preop
Optimize hemodynamic & coagulation status
Check blood product availability
ETT & catheter placement
Adequate IV access
Know acceptable hemodynamic parameters (HR, BP, SpO2, FiO2)
NEC
Intraop
Standard monitoring Arterial catheter Maintain hemodynamic stability Vasoactive support (Dopamine or Epi gtt) Opioids or low-dose inhalation anesthetic agent w/ neuromuscular paralysis Check glucose levels & electrolytes Fluid resuscitation PRBC, FFP, cryo Temperature homeostasis - forced air warmer
NEC
Postop
Mechanical ventilation
Sedation
Analgesia
Inguinal Hernia
1/3 pre-term infants
1% full-term neonates
Inguinal Hernia
Complications
Incarcerated bowel Intestinal obstruction Gonadal infarction Infection Hematoma Recurrent hernias
Inguinal Hernia Repair
General or regional anesthesia
Small defect consider LMA
Large defects requiring muscle relaxation → ETT
Ilioinguinal, iliohypogastric, or caudal/epidural blocks
ROP Treatment
Cryotherapy - freezing probe to avascular retina, requires general anesthesia, 32-42wks corrected
Laser photocoagulation - moderate ROP 10-30min every few weeks
Scleral bucking surgery or vitrectomy - severe ROP w/ retinal detachment > 6mos-1yo
- Requires general
CDH
Congenital diaphragmatic hernia
Anatomic defects permit abdominal contents to intrude into thoracic cavity
Asymptomatic → life-threatening
Early - abdominal mass inhibits normal cardiopulmonary growth; severe lung hypoplasia associated w/ morbidity & mortality; negatively correlates w/ gestational age at time hernia occurred
Late - occurs near or even after delivery, mature well-developed lungs, minimal problems w/ ventilation
When does the diaphragm formation complete in utero?
Week 7-10
Most common CDH type
Bochdalek hernia 95%
More likely to have concurrent birth defects & chromosomal abnormalities
L sided lesions 7x more frequent
CDH S/S
Hypoxia
Scaphoid abdomen
Bowel sounds in thorax
CDH Complications
Abdominal viscera present in thoracic cavity itself not life-threatening rather the compression effects on developing pulmonary structures obstruct smooth transition from fetal to neonatal circulatory pattern
- Hypoplastic lungs
- Intrapulmonary shunting & inadequate gas exchange
- ↓total cross-sectional area results in pulmonary arteriole HTN
CDH
Anesthetic Considerations
Initial management - airway control & optimize oxygenation/ventilation
Avoid mask ventilation to limit gastric insufflation
Place NG tube to decompress stomach
Supine or lateral dependent on defect location
Pre & post-ductal monitoring R → L shunt or pulmonary HTN
- PIV x2 and/or CVC
- A-line or UAC
- Serial ABGs
- EBL 5-10mL/kg
- PRBCs available
Limit inhalational agent, paralysis, & narcotics
Avoid nitrous oxide
Prevent excessive oxygenation
Sedation important to limit catecholamine response
CDH
Surgical Approaches
Recurrent defects - minimally invasive approach through abdomen
Primary closure vs. synthetic path
Delay closure until cardiorespiratory & medically stabilization
Before, during, or after ECMO
Transiently worsens pulmonary HTN → persistent fetal circulation (PDA open & shunts blood R → L bypassing lungs)
Outcomes 1° dependent on underlying pulmonary hyperplasia & HTN
Stabilize cardiorespiratory status during transition from intrauterine to extrauterine before surgical repair
- 48hrs to 4-6 days old
- Stabilize in NICU before OR
Inhaled Nitric Oxide
Pulmonary vasodilator (avoids systemic hypotension)
Refractory pulmonary HTN treatment ↓ R → L shunt & improve oxygenation
Short acting
VV ECMO
Temporary measure allows lungs to rest & mature while providing appropriate gas exchange through membrane oxygenators
Venovenous
Double lumen resides in IJ vein
VA ECMO
Temporary measure allows lungs to rest & mature while providing appropriate gas exchange through membrane oxygenators
Venoarterial
Two catheters - IJ vein & carotid artery
ECMO Contraindications
IVH
Obtain HUS 1st
How should CRNAs approach & treat severe cardiovascular compromise in CDH?
Volume & inotropic support
Dopamine
Malrotation
Intestines twist around superior mesenteric artery → kink & compress vascular supply
Atretic segments, compromised perfusion, & intestinal ischemia
Volvulus
Bowl strangulation & shock
Malrotation & Midgut Volvulus
Presentation
Bilious emesis Abdominal distension Hemodynamic instability Hypotension Hypovolemia Electrolyte abnormalities Bloody stools
Surgical emergency - necrosis risk
Omphalocele
Hernia or rupture at the umbilicus
Failure gut to migrate from yolk sac into the abdomen
Associated genetic, cardiac, urologic, & metabolic abnormalities
Viscera emerge from umbilicus & covered w/ membranous sac
Gastroschisis
Herniated viscera exposed to air after delivery
Risk inflammation, edema, & dilation /w abnormal bowel function
Not usually associated w/ other congenital abnormalities
Omphalocele & Gastroschisis
Medical Management
Maintain perfusion & prevent fluid loss
Goal = abdominal closure (often delayed to avoid exposing the viscera to excessive pressure)
↑intra-abdominal pressure → cardiorespiratory failure, renal failure, ↓hepatic function, ischemic bowel, & death
Pressures >20mmHg poorly tolerated
Omphalocele & Gastroschisis
Postop
Assess ability to extubate
Continue gastric suction
IV nutrition TPN weeks → months
Often remain intubated w/ IV sedation, paralytics, & opioids
Criteria to Abort 1° Closure
Intra-gastric pressure >20mmHg
Intra-vesical pressure >20mmHg
ETCO2 >50mmHg
PIP (ventilatory pressures) >35cmH2O
VACTERL
Vertebral abnormalities Imperforated anus Congenital heart disease Tracheo- Esophageal fistula Renal abnormalities Limb abnormalities
Esophageal Atresia
Esophagus does not connect to stomach
Tracheoesophageal Fistula
S/S
TEF
Normally diagnosed immediately after birth
Excessive secretions, coughing, & choking after 1st feeding
Additional indicators - recurrent pneumonias & unable to pass OG
TEF Associated Risks
Pneumonia, poor nutrition, gastric distension → impaired ventilation
TEF Types
Esophageal atresia w/ distal TEF Isolated esophageal atresia 8% Isolated TEF 4% Esophageal atresia w/ proximal TEF 1% Esophageal atresia w/ double TEF 1%
Most common TEF type _____
Esophageal atresia w/ distal TEF 87%
Type C/IIIB
TEF
Anesthetic Considerations
Consider "awake" fiberoptic intubation Avoid +pressure ventilation RSI induction Place ETT b/w fistula & carina Avoid nitrous oxide Surgical traction effect on lung, vasculature, trachea, heart, & Vagus nerve
What does precipitous O2 desaturation in TEF repair indicate?
Atelectasis & secretions → pulmonary blood flow shunt
Lung tissue retraction
Tracheal & bronchial compression
Bleeding
ETT malposition (utilize L sided precordial to assess tube migration)
Arterial hypoxia → surgeon release traction & perform alveolar recruitment maneuvers
TEF Complications
Anastomosis leaks & strictures GERD Feeding aversions Esophageal dysmotility Strictures Pulmonary disease Tracheomalacia
Average neonate oxygen consumption
5-8mL/kg/min
Adult 2-3mL/kg/min
What causes an increased CO2 production in neonates?
How do they compensate for this change?
↑metabolic rate ↑CO2 production
↑respiratory rate to facilitate CO2 elimination
Fetal Hgb has an _____ oxygen affinity
INCREASED
↓oxygen Hgb release → tissues
What postop complication needs to be closely monitored for in neonates?
APNEA
