Prematurity Flashcards
Anesthetics have both________and _________ properties.
_________protect against __________Ischemic injury
Anesthetics have both neuroprotective and neurotoxic properties
• Volatiles protect against hypoxic-ischemic injury
• Better than IV agents
c/surgeries c/ risk of brain ischemia
• VP shunt, cardiac, vein embolization
Anesthesia DOES
PRE CONDITIONING in heart and brain
• Studies showed prolonged exposure of commonly used anesthetics in primates and rats →
neuroapoptosis
• Human premies might have more risk of
anesthetic neurotoxicity
• However, neurodegeneration and apoptosis is part of
normal developmental phenomenon
When anesthesia is combined with surgery, more
neuroapoptosis occurs than with either alone
• Anesthetic neuro-degeneration depends on
age, brain region, and duration
- Inhalational anesthetics
* MAC of isoflurane in micropremie (
32 weeks PCA; 20% less than term neonates
• All ages experienced a @ 1 MAC of iso
20-30% decrease in SBP (SVR goes down, myocardial suppression)
Premies might have more risk of cardiac depression
•
Neonatal heart depends on iCa2+ for contractractility
Inhalational anesthetics block calcium channels
Only FDA approved for induction
SEVOFLURANE
NO inhalation with bad lung condition s
DESFLURANE
- Intravenous agents
- Preterm infant might be inherently amnestic by virtue of age
- Fentanyl =
hemodynamic stability, no amnesia or areflexia
Conditions to PRODUCE ANESTHESIA
Sedation, amnesia, analgesia, AREFLEXIA
Clearance in premies remained constant up to_______
120 minutes = ↓clearance
- Elimination ½ life in premies =
* ↑
6-32 hours (2-3 hr in children/adults)
Vd of fentanyl
Hepatic in PREMIES
• Might be due to immature CYP 450 3A4 and ↓hepatic function
PREMIES have
ABNORMAL PHARMACOKINETICS May go apneic, BRADYCARDIA Slow to recover RESPIRATORY DEPRESSIOn MORE RISK OF POST OP APNEA
- Intravenous agents
- Morphine
- Elimination half-life in micropremie =
- Reduced elimination of__________
- More _________effects when compared c/ fentanyl
6-16hrs (2-4 in adults)
morphine-6-glucuronide
hemodynamic
Remifentanil
• Elimination half-life =_________
•____________
• Premies have normal-high levels of_____________
3-4 min in all pts
Independent of duration
nonspecific esterase activity
REMIFENTANYL
NO PAIN RELIEF AFTERWARDS
CAUTION with Fentanyl products
CHEST WALL RIGIDITY
Ketamine •\_\_\_\_\_\_\_,\_\_\_\_\_\_\_,\_\_\_\_\_\_ • Minimal\_\_\_\_\_\_\_\_\_\_\_\_ • Can\_\_\_\_\_\_\_\_\_ → • Always\_\_\_\_\_\_\_ unless brief painful procedure
Analgesia, amnesia, unconsciousness
↓CV function (stimulates)
↓ventilation/airway reflexes; airway obstruction, apnea, aspiration
use ETT
• Caution c/ blousing (1-3mg/kg IV) =
protracted hypotension +↓CO in otherwise stable infants → hypoxia
• Possibilities of Propofol
systemic vasodilation, acute pulmonary HTN with reversion to persistent fetal circulation
• Recovery delayed in micropremies
(↓ fat/muscle for redistribution, ↓ clearance)
- Intravenous agents
- Midazolam
- ______clearance in micropremie
- Further prolonged________
- _______________
- Hypotension even greater if administered
↓
with ↓ liver function
Systemic hypotension, ↓ ventilation, impaired airway reflexes in premies
c/ fentanyl
- Regional anesthesia
* None of the complications listed above!
↑risk of infection, injury, bleeding
↑local doses per kg required in infants (↑Vd in CSF, ↑surface area of spinal cord/nerve roots, ↑CO/BF to spinal cord = faster distribution, uptake, and elimination = ↓ DOA
Preparation for a Neonatal Emergency
- Is it an “urgent” emergency?
- Normally have time to medically optimize
- Warm the patient
- ↑OR temp 80°F to 85°F (normally 60-65°F)
- Radiant warming units
- Forced air heating pads
- Humidify FGF (or rebreathe)
Preparation for a Neonatal Emergency: Monitors
• EKG, chest/esophageal stethoscope, BP, temperature probe, pulse oximeter, ETCO2 and agent analyzer
Preparation for a Neonatal Emergency: Oxygen saturation
Normally limit use of O2 to keep SpO2 between 83-95% to ↓ oxidative stress
• Anesthesia and surgery adversely affect oxygenation → we use it!
• In event of PDA still present, take sats at right hand and left hand/foot to assess extra-pulmonary shunting of DeO2 blood via PDA
- Circuit adds __________ → ETCO2 underestimates _______
- Large VD when neonates use ___________
- Usually have _________
- Might need to _____ ________ during parts of surgery
- Esp with old ventilators
- Consider asking NICU to send one
- Umbilical venous catheter =________
- Umbilical arterial catheter = _________
- Umbilical catheters can only be used up to______Days
- Circuit adds dead space volume (VD) → ETCO2 underestimates PaCO2
- Large VD when neonates use very small TV
- Usually have bad lungs
- Might need to ventilate manually during parts of surgery
- Esp c/old ventilators
- Consider asking NICU to send one
- Umbilical venous catheter = central line
- Umbilical arterial catheter = A-line
- Umbilical catheters can only be used up to 7-10 days
Equipment to always have on hand
Suction catheters, various face masks, oral airways, pediatric breathing circuits, laryngoscopes, numerous small ETT, IVF warmer, body warmers, LR, D10W, NS, 5%
albumin
• Emergency drugs:
atropine, epi (1:10,000),
dopamine, calcium, bicarbonate,
isoproterenol
• Medication administration • Only draw up \_\_\_\_\_\_\_\_\_\_\_\_ • Tuberculin needle needed \_\_\_\_\_\_\_\_\_ (e.g. 5 mcg fentanyl) • If diluting, \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Always administer\_\_\_\_\_\_\_\_\_always \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Keep empty labeled syringes until the end of case
• Only draw up what you intend to give
• Tuberculin needle needed for small doses (e.g. 5
mcg fentanyl)
• If diluting, verify concentration c/ someone
• Always administer in port closest to pt, always
flush line after administering
• Keep empty labeled syringes until the end of case
- Fluid maintenance
- Fluid overload can open _______________
- NO _____________
- Continue whatever they were getting in ______because it Contains ______and _________
- Do NOT stop _____or _________ why?
- If no fluids are going, use ________or _____
- Fluid overload can open a DA and cause CHF
- NO AIR BUBBLES
- Continue whatever they were getting in NICU
- Contains glucose and calcium
- Do NOT stop TPN or dextrose
- Maybe slightly ↓rate to ward off hyperglycemia
- If no fluids are going, use LR or plasmalyte
**CHOANAL ATRESIA is
Developmental failure of ______ _____________
• Associated with ____________
• CHARGE syndrome
- Treacher-Collins
- Pfeiffer
- VATER
- _____________________
Developmental failure of nasal cavity to communicate c/
nasopharynx
• Associated c/ other congenital anomalies
• CHARGE syndrome
• (Coloboma,Heart disease, Atresia
choanae, Retarded growth, Genital anomalies, Ear
anomalies)
• Treacher-Collins
• Pfeiffer
• VATER
• (Vertebral defects, Anal
atresia, Tracheoesophageal fistula c/ Esophageal
atresia, and Radial and renal anomalies
*****CHOANAL ATRESIA Only a surgical emergency if\_\_\_\_\_\_\_\_\_\_\_ • Presents c/in\_\_\_\_\_\_\_\_\_ • Resp distress, \_\_\_\_\_\_\_\_\_cyanosis • High risk for airway obstruction • Oral airway early
bilateral stenosis present
5 days of life
(associated c/feeding; relieved by crying)
**TEF is
Error in _______________ around______week gestation
• VACTERL association
__________________
• Diagnosis: ____________________
MOST SEEN IS ______________
Early postnatal s/s: excessive salivation,
choking/coughing/regurgitation at first feed → cyanosis and/or respiratory distress, distended abdomen (stomach filling c/ air every time the baby cries) → may compress the lung and ↓ resp
Error in separation of trachea from floor of the foregut around 4th-5 th wk gestation
• VACTERL association
• (Vertebral anomalies, imperforate Anus, Congenital heart
disease,Tracheoesophageal fistula, Renal abnormalities, LIMB ABNORMALITIES*)
• Diagnosis: polyhydramnios (cant swallow)
Early postnatal s/s: excessive salivation,
choking/coughing/regurgitation at first feed → cyanosis and/or
respiratory distress, distended abdomen (stomach filling c/ air every
time the baby cries) → may compress the lung and ↓ resp
MOst common TEF
TYPE C
Most common type TEF
(Gross classification C, type IIIB in Vogt) consists
of blind proximal esophageal pouch (atresia) c/ a distal TEF just above the carina • (80%–90% of cases)
TEF • NOT a \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • IV access, correct anemia, F/E imbalances, type and crossmatch, *****look for o\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_*****, place \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Surgical repair • Traditional =\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Thorascopic repair gaining popularity • OLV no longer required
• NOT a surgical emergency
• IV access, correct anemia, F/E imbalances, type and crossmatch, look for
other congenital anomalies, place gastrostomy tube
• Surgical repair
• Traditional = open thoracotomy c/manual lung retraction
• Thorascopic repair gaining popularity
• OLV no longer required
With TEF
Can’t feed through ESOPHAGUS
TEF Anesthesia Considerations
- Anesthesia considerations
- Option 1: keep baby spont. vent.
- Inhalation induction
- Avoiding positive pressure ventilation ↓ amount of gas entering stomach
Option 2: gentle mask ventilation c/low peak pressure ventilation
• ↓ amount of gas entering stomach
• Tip of ETT must be placed above carina but distal to fistula
• Right mainstem tube on purpose, then slowly c/draw until you have first bilateral breath sound
• Fiberoptic scope
• Pain: epidural catheter threaded from caudal to thoracic space
Congenital Diaphragmatic Hernia (CDH) ✤ Failure of \_\_\_\_\_\_ • Inhibits normal\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_ of bronchi/alveoli •\_\_\_\_\_\_\_\_\_\_PVR/ Pulmonary HTN ✤ Etiology \_\_\_\_\_\_\_\_\_ ✤ Diaphragm formation at \_\_\_\_\_\_\_\_\_\_ Separates the chest and abdomen • Hernia forms around \_\_\_\_\_\_\_\_ ✤ Hernia: Intestine penetrates the hole in the diaphragm and enters the chest ✤ Not a surgical emergency • Optimize medically first
✤ Failure of closure of pleural + peritoneal canal → herniation of abd contents into thorax • Inhibits normal lung growth • ↓# of bronchi/alveoli • ↑PVR + primary pulmonary HTN ✤ Etiology unknown ✤ Diaphragm formation at 5 - 10 wks gestation • Separates the chest and abdomen • Hernia forms around 8 wks ✤ Hernia: Intestine penetrates the hole in the diaphragm and enters the chest ✤ Not a surgical emergency • Optimize medically first
Congenital Diaphragmatic Hernia
CDH
Left side closes last
• 90% CDH occur at foramen of Bockdalek
• Largest degree of pulm hypoplasia
• Associated c/ congenital heart defects,
chromosomal abnormalities, GU/GI malformations
• ↑PVR → R-to-L shunt via PFO and DA
• Hypoxemia
• Respiratory distress, tachycardia, tachypnea, and
cyanosis observed shortly after delivery
• At birth: ↓ breath sounds, bowel sounds in
thorax, resp insuff, barrel chest, scaphoid abd
Anesthesia considerations of CONGENTIAL DIAPHRAGMATIC HERNIA Anesthesia considerations: • Gentle mechanical ventilation to avoid \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Frequent, small \_\_\_\_\_\_\_\_\_\_\_\_ • Permissive hypercapnia \_\_\_\_\_\_\_\_\_\_\_ • Avoid \_\_\_\_\_\_\_\_ • \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Avoid introducing \_\_\_\_\_\_\_\_\_\_\_\_ • Insert \_\_\_\_\_\_\_\_ • Avoid\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Avoid \_\_\_\_\_\_\_\_\_\_\_
- Gentle mechanical ventilation to avoid pneumothorax/barotrauma/volutrauma
- Frequent, small TV breaths c/limited peak inspiratory pressures (< 20 cm H2O)
- Permissive hypercapnia 60-65 mm Hg
- Avoid ↑PVR
- Hypoxemia, acidosis, hypothermia, hypercarbia
- Avoid introducing air to GI tract
- Insert NGT before induction
- Avoid CPAP and prolonged mask vent
- Avoid N2O
CDH surgical
• Open surgical transabdominal approach vs
thoracoscopy
• If abd too small to accommodate additional
bowels → intense ↓pulm compliance,
desaturation, hypercapnia
• OLV not always necessary anymore
• CO2 insufflation to collapse lung
CHD Temporary fetoscopic tracheal plugging Performed \_\_\_\_\_\_weeks of gestation • Prevents outflow of\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ • Retained fluid helps enlarge lungs, accelerates growth, reduces mass effect of herniated bowels
• Temporary fetoscopic tracheal
plugging • Performed 25 -28 weeks gestation
• Prevents outflow of surfactant -rich fetal fluid
GI PATHOLOGY
NOT a surgical emergency UNLESS
• All considered full stomachs
• Suction gastric contents first, then RSI
• Avoid N2O d/t intestinal distention
NOT a surgical emergency unless compromised organ blood flow*
• Correct underlying medical issues and achieve euvolemia
• Prone to:
• ↓BP
• Metabolic abnormalities (↑K+)
• Anemia
• Thrombocytopenia
Hypertrophic Pyloric Stenosis
What kind of Vomiting?
How long does it take for metabolic derangements to be fixed?
Signs of proper optimization
• 1/500 live births
• Usually presents 2-8 weeks of age c/:
• Nonbilious projectile vomiting
→ ↓K+ ↓Cl- metabolic alkalosis–>Severe cases progress to metabolic acidosis
NOT a life threatening emergency
Fixing metabolic derangements and fluid
status takes 24-48hrs
Signs of proper medical optimization: UOP of 1-2 mL/kg/hr or more Na+ > 130 mEq/L K+ > 3.0 mEq/L Cl- > 85 mEq/
Hypertrophic is______Vomiting
NON-BILIOIUS
Treatment of HPS
pyloromyotomy
• Anesthesia considerations:
• Modified RSI
• Maybe inhalation induction
• Muscle relaxation not always necessary in every case
• Opioids typically not needed
• Local combined c/ acetaminophen or an NSAID normally enough
Duodenal Atresia • Duodenal Atresia it is a \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_ associated c/ other congenital anomalies (OBSTRUCTION after bile duct) • Presentation: \_\_\_\_\_\_\_\_vomiting beginning \_\_\_\_\_\_\_\_\_\_→\_\_\_\_\_\_\_\_\_\_\_\_ NOT a surgical emergency, medically optimize first • Abdominal XR show \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
Congenital absence or complete closure of a portion of the lumen of duodenum
50 -70% associated c/ other congenital anomalies
Presentation: • Bilious vomiting beginning 24 -48hrs
after birth →dehydration + F/E imbalance
• NOT a surgical emergency, medically optimize first
• Abdominal XR show “double bubble” sign • Air trapped in stomach and proximal duodenum
INGUINAL HERNIA
IT is a Protrusion of _____________
• Typically occurs within _____________
_____________ →***true surgical emergency
• Elective should receive _______ • Caudal, spinal, ilioinguinal block, TAP block
Protrusion of abdominal cavity and gonadal structures through the inguinal canal • Failure of process vaginalis to close
• Typically occurs c/in 6 mo of life and more
prevalent in males
• Incarcerated or strangulated hernia →true
surgical emergency
• Elective should receive regional • Caudal, spinal, ilioinguinal block, TAP block
Necrotizing Enterocolitis (NEC)
It is a multifactorial ____________
_____mortality rate
Potential etiologies:
Associated with
Multifactorial disease that can lead to bowel necrosis
• Leading cause of neonatal mortality
• 10-50% mortality rate
• Potential etiologies:
• Unbalanced inflammatory responses of bowel mucosa, alterations in normal intestinal flora by antibiotics and feeds, and lack of a fully developed intestinal mucosal barrier → breakdown of intestinal wall and bowel necrosis
Associated c/:
• Prematurity, low systemic cardiac output, hypoxia, PDA, infection, red blood cell transfusion, and enteral feedings (especially formula-fed neonates)
Leading cause of NEONATAL MORTALITY
NECROTIZING ENTEROCOLITIS
Early signs of NEC
• Early Signs • Temp instability, poor feeding c/ residual
volumes or vomiting, lethargy, apnea,
bradycardia, mild abdominal distention, and
bloody stools
Late signs of NEC
• Late signs • Tachycardia, poor perfusion/hypotension,
metabolic acidosis, thrombocytopenia, abdominal tenderness, and peritonitis
• Abd XR of NEC shows
ileus c/ thickened bowel walls and dilated
loops, later gas in the intestinal wall and in
hepatobiliary tract or portal venous system
***PROMPT SURGICAL INTERVENTIO of NEC, if you find
**• Finding free air in abd cavity = prompt surgical
intervention
- Fast preop prep of NEC
- Predisposed to ________________
- Septic and volume depleted c/ ______________as the result of massive third-space losses
- Enormous need for ____________ just to maintain intravascular volume (up to 1 blood volume of more) because of third spacing
- Hypokalemia c/ renal failure common
- Commonly need plt and FFP transfusion
- CVP for inotropic support (dopamine, epi)
Predisposed to hypovolemia, CV and resp failure, capillary leak syndrome, DIC, and hypoglycemia
• Septic and volume depleted c/ very large fluid requirements as the result of massive third-space losses
• Enormous need for 5% albumin just to maintain intravascular volume (up to 1 blood volume of more) because of third spacing
• Hypokalemia c/ renal failure common
• Commonly need plt and FFP transfusion
• CVP for inotropic support (dopamine, epi)
OMPHACELE
Failure of gut to migrate from yolk sac into
abd during gestation
• 1/5000 births
• Commonly have other issues:
• associated genetic, cardiac, urologic, metabolic abnormalities, visceromegaly, macroglossia, hypoglycemia, polycythemia
• Bowel looks and functions normally
Gastroschisis
• Results from occlusion of the omphalomesenteric artery during gestation
• 1/2000 births
• Usually not associated c/congenital anomalies
• Due to exposure, present c/inflammation, edema, and dilated,
foreshortened, functionally abnormal bowel
• Keep covered c/ saline-soaked dressings
• Extreme evaporative volume loss and hypothermia –> More than omphalocele
Anesthesia Considerations for GASTRO and OMP
Volume replacement • Prevention hypothermia • Monitor intra-abdominal pressure (IAP) • > 20 mm Hg after surgery → abd ischemia, urgent reoperation → ↓ organ perfusion and ventilatory reserve, including perfusion of the intestines, kidney, and liver •
Altered metabolism/eliminatio n/prolongation of meds
Malrotation and Midgut Volvulus
Etiology:
• Abnormal migration or incomplete rotation of intestines from yolk sac back into abdomen
• 1/500 births
• 30-60% have other congenial anomalies
Presentation: • Bilious emesis, tender and distended abdomen, increasing abdominal girth, hypotension, hypovolemia, and electrolyte abnormalities • True neonatal surgical emergency • Do NOT delay surgery to correct F/E imbalances
Hirschsprung Disease
• Absence of parasympathetic ganglion
cells in large intestine • Nonperistaltic segment, tonically
contracted anorectal sphincter, and delayed passage of meconium • Functional obstruction
• Symptoms: bilious vomiting, abd distention
• Compromised blood supply
→perforation
• Enteric bacteria invasion of bowel
wall to bloodstream → toxic megacolon
• 60% have other associated anomalies • Require massive volume replacement and vasopressor support
Ligation of Patent Ductus Arteriosus
• Controversial procedure due to conflicting
evidence • 1/3 develop severe cardiovascular instability • Increased risk of chronic lung disease, ROP,
and neurosensory impairment after ligation
• Medical management: cyclooxygenase inhibitor,
such as indomethacin or ibuprofen • Indomethacin in premies may cause: thrombocytopenia, renal failure,
hyponatremia, and intestinal perforation
• Ibuprofen works just as well s/complications • Paracetamol being used c/ equal effectiveness
Ligation of Patent Ductus Arteriosus surgica
• Surgical correction: Left thoracotomy c/ manual
retraction of lung
• Hard to distinguish PDA from aorta
• Monitoring BP and pulsox on right arm
(preductal) and oximetry on the foot
(postductal) will assist surgeon to ID
correct vessel to be ligated
• Temporary clamp placed on perceived PDA
• If aorta is clamped → loss of post ductal oximetry
• If PA is clamped → ↓in both oximeters and ↓ETCO2
• Successful PDA ligation → ↑MAP (↑DBP) + NO changes in pulse oximeters
Ligation of Patent Ductus: Transcatheter occlusion of PDA
MOST COMMON complications are
- Coils or occlude device
- Similar efficacy to traditional surgery
- Can be done in NICU c/ echo guidance
- More rapid recovery of resp function
• Most common complications
- ->Femoral artery thrombosis
- -> Left pulmonary artery stenosis
- -> Aortic coarctation
COMPARE OMPHACELE and GASTROCHISIS
Know
