Pediatric Anesthesia Quiz #7 Flashcards
(95 cards)
1
Q
Pediatric Trauma.
A
- Injuries: Leading cause of DEATH and DISABILITY in the pediatric population of the US
- Up to 40% of polytrauma patients die as result of circulatory shock from acute blood loss
- Besides surgical control of hemorrhage, adequate volume resuscitation with blood products and fluids is crucial for survival of these victims
2
Q
Unintentional Cause of Injury.
A
- 1 to 4: 10.6:100,000
- 15-19: 32.5:100K
3
Q
Assault Cause of Injury
A
- 1 to 4: 2.2:100K
- 15-19: 9.1:100K
4
Q
Self harm or suicide
A
Highest: 7.1:100K
5
Q
What is the most common cause of death from injury for victims of all ages?
A
- Traumatic brain injury
- Vehicular trauma is the major threat
- Initial management and definitive care of child with traumatic head injury: optimize cerebral perfusion to minimize extension of injury and maximize recovery of the damaged neurons while simultaneously managing extracranial injury so as to assure return to full functionality
6
Q
Primary Goals of management of pediatric trauma pts.
A
- Delivery of O2
- Appropriate ventilation
- Perfusion to vital organs
- Maintenance of normothermia to mild hypothermia
- Assurance of renal function
- Neurologic stability
- Correction of coagulopathies
- Avoidance of overhydration
- Meticulous management of metabolic demands
7
Q
Report from the Field
A
-Age, sex, mechanism of injury (MVA vs. FALL), obvious injuries, airway management (SV vs. intubation), VS, IV access, loss of consciousness, ETA
Prepare for trauma pt. with estimated weight:
-Blood availability, RSI and Rescue drugs, suction, anesthesia machine check, blades/ETT, airway cart/fiberoptic bronchoscope/LMA, rapid infuser/IV fluids
8
Q
RSI drugs for Pediatric Trauma Pts.
A
Atropine: 10-20 mcg/kg (min 0.1 mg) Glyco: 10 mcg/kg Midazolam: 0.05-0.1 mg/kg Fentanyl: 1-2 mcg/kg Lidocaine: 1-1.5 mg/kg Propofol: 2-4 mg/kg Ketamine: 1-2 mg/kg Thiopental: 4-6 mg/kg Etomidate: 0.3 mg/kg Rocuronium: 1.2 mg/kg Succinylcholine: 1.5-2 mg/kg
9
Q
Resuscitation Drugs
A
Epinephrine: 1 mcg/kg to treat hypotension
Epinephrine: 10 mcg/kg for cardiac arrest
Atropine: 20 mcg/kg IV for symptomatic bradycardia
max dose: 1 mg for child, 2 mg for adolescent
Bicarbonate: 1-2 mEq/kg IV (guided by ABG results)
CaCl: 10-20 mg/kg IV (preferred CVC, slowly)
Ca Gluconate: 30-60 mg/kg IV (PIV is ok)
Lidocaine: 1 mg/kg IV, followed by 20-50 mcg/kg/MIN infusion
Adenosine (adenocard):
- 1st dose: 100 mcg/kg rapid IV bolus and flush (max 6 mg)
- 2nd dose: 200 mcg/kg and flush (max 12 mg)
Amiodorone: 5 mg/kg IV (max 300 mg) for Vfib/Vtach
Procainamide (Pronestyl): 5-15 mg/kg IV loading dose over 30-60 min, then 20-80 mcg/kg/MIN infusion. ECG monitoring required
Magnesium: 25-50 mg/kg IV (max 2 gm) for torsades de pointes
10
Q
Vasoactive Drugs
A
- Via IV pump
- Consider Arterial pressure monitoring
Dopamine: 1-20 mcg/kg/min
Dobutamine: 1-20 mcg/kg/min
Epinephrine: 0.1-1 mcg/kg/min
Isoproterenol: 0.1-1 mcg/kg/min
Norepi: 0.1-1 mcg/kg/min
Phenylephrine: 0.1-1 mcg/kg/min
Milrinone (primacor):
- 50-100 mcg/kg loading dose
- 0.5-1 mcg/kg/min
Nitroprusside (nipride): 1-10 mcg/kg/min
Nitroglycerine: 1-10 mcg/kg/min
Prostaglandin E1: 0.05 mcg/kg/min
Vasopressin (pitressin): 0.0001-0.0005 units/kg/min
11
Q
Donor Blood
A
- When there is no time for blood typing and crossmatching: Group O RBCs and AB plasma products and platelets should be used until the patient’s blood type is known
- Women of childbearing potential: receive group O- RBCs until type-specific and cross-match blood is available
- Men and women post-childbearing age could receive O+ RBCs if supply of O- RBCs is limited
12
Q
How much does 4 ml/kg of PRBCs increase hemoglobin?
A
-by 1 g/dL
13
Q
How much does 5-10 ml/kg of Platelets increase plt count?
A
-by 50-100K/mm^3
14
Q
How much does 10-15 ml/kg of FFP increase factor level?
A
-by 15-20%
15
Q
How much does 1-2 units/kg increase fibrinogen level?
A
-60-100 mg/dL
16
Q
What are the reasons for up to 50% of deaths in the first 24 hours after injury and greater than 80% of deaths in the OR?
A
- Hemorrhagic shock
- Exsanguination
- Death typically occurs quickly within 6 hours of injury
- 3-5% of civilian trauma pts will require a massive blood transfusion
17
Q
T or F: Recent studies have shown that at least 25% of poly-trauma pts arrive at trauma center already coagulopathic
A
- True
- These pts are at a markedly higher risk of mortality
- With this combination of massive blood loss and coagulopathy, it has become increasingly more common to transfuse EARLY the trauma pts and with a combination of: PRBC, plasma (FFP), and platelets
18
Q
Trauma Triad of Death.
A
- Coagulopathy
- Acidosis
- Hypothermia
These have led to the concepts of damage control surgery and resuscitation
19
Q
Massive Blood Transfusion.
A
-Transfusion of large quantities of blood components
May seriously affect:
- Coagulation (coagulopathy)
- Potassium and calcium concentrations
- Acid/base balance (acidosis)
- Body temperature (hypothermia)
- Oxygen-hemoglobin dissociation
- Hematocrit (oxygen-carrying capacity)
20
Q
What do we need to create a blood clot?
A
-Platelets (stick to exposed collagen, release XII, activate and support coagulation cascade, create platelet plug)
21
Q
Clotting Factors
A
Extrinsic: Tissue factor, VII, V
Intrinsic: XII, XI, IX, VIII
Common: X, thrombin (II), fibrinogen (I), XIII (fibrin stabilizer)
22
Q
Ca+ Ions
A
-Play major role in activating clotting factors, vasoconstriction of blood vessels
23
Q
RBCs:
A
-Transport of respiratory gases to and from tissues
24
Q
Platelets:
A
-If overt signs of bleeding are present or a more significant hemostatic challenge in the form of a surgical procedure is imminent: required level is 30K-50K/mm^3!!!
- Platelets should be filtered only by large-pore filters (≥150 micrometers)
- Should NOT be refrigerated or placed in cooler with ice!!
25
FFP:
- Fresh Frozen Plasma
- Contains ALL of the clotting factors
- All regulatory proteins
- Only massively transfused pts could potentially benefit from a higher FFP:RBC (1:1) ratio.
- However, increased FFP transfusions to non-massively transfused pts were associated with a trend toward increased mortality (ARDS) and increased risk of developing transfusion related acute lung injury (TRALI)
- Rapid admin. of FFP can cause Citrate Toxicity
26
Citrate Toxicity:
- Citrate chelates Ca and Mg and is added to FFP and platelets to prevent clotting during storage in BB
- Remaining citrate in blood products during massive blood transfusions will cause hypocalcemia
- S&S of hypocalcemia: hypotension and arrhythmias
- Citrate intoxication: more likely in setting of hypothermia, liver disease/transplantation (citrate is mostly metabolized by liver), and is more likely in pediatric pts
27
How do you treat Citrate Toxicity?
Ca Gluconate: 30-60 mg/kg IV
CaCl: 10-20 mg/kg IV
28
Cryoprecipitate
- Contains 20-50% of Factor VIII form the original unit of plasma
- Also contains von Willebrand factor (vWF), fibrinogen (approx. 250 mg), and factor XIII
- Indicated for treatment of: factor XIII deficiency, dysfibrinogenemia, and hypofibrinogenemia
29
Preterm neonate EBV
90-100 ml/kg
30
Full-term neonate EBV
80-90 mL/kg
31
Infant(=12 months) EBV
70-80 mL/kg
32
Toddler/school-age child (≤ 12 yrs) EBV
70 ml/kg
33
Teenager (> 13 yrs)/Adult EBV
65-70 mL/kg
34
Obese Child EBV
60-65 ml/kg
35
Maximal Allowable Blood Loss (MABL)
- EBV
- Pts hematocrit before blood loss (Hct)
- Pt's minimum accepted hematocrit (maHct) before transfusion
MABL = EBV x (Hct - maHct)/Hct
36
-10 kg child (infant) with Hct of 42% who will be allowed to drift down to Hct of 25% (maHct)
- EBV = 80 ml/kg: 800 ml
- MABL = 800 x (42-25)/42 = 324 ml
- The child can lose 324 ml blood before a potential blood transfusion
37
Volume of PRBCs to be transfused...
EBV (ml) x (desired Hct - present Hct)/ Hct of PRBCs (~60)
38
- Volume of PRBCs to be transfused of 10 kg child
- Desired Hct: 35
- Present Hct: 23
(80 x 10) x (35 - 23)/ 60 = 800 x 12/60 = 160 ml PRBCs
16o ml of PRBCs should be transfused to increase the Hct from 23 to 35
39
Hematocrit:
- Balance between O2 supply and demand depends on a number of factors, including the O2 content of blood, CO, and its regional distribution, and metabolic needs
- A child with severe pulmonary disease or cyanotic CHD requires a GREATER HCT than a healthy child
- Preterm infants may require a GREATER HCT to prevent apnea, reduce cardiac and respiratory work, and possibly improve neurologic outcomes
40
What is an acceptable Hct in healthy infants up to about 3 months of age if there is little potential for post-op bleeding? 3 months or older?
- 20-25% Hct
- 20% in older
- Observe operative field (EBL)
- Monitor VS, Hct, U/O, and CVP
- Each help to assess the adequacy of volume replacement!!
41
Cervical Spine Precautions:
Cervical Spine Precautions -Risk of spine injury increased: child subjected to INERTIAL force from Falls, or the chaotic Rotary Forces associated with Motor Vehicle crashes
- If suspected: Cervical Spine Precautions implemented (collar device immobilization, etc)
- In-line stabilization should always be maintained when airway manipulation is attempted
42
Intubation of a child with a cervical fracture may require up to how many individuals?
- Four!
- One to provide in-line stabilization
- Second to perform the intubation
- Third to perform cricoid pressure and either hold the ETT or retract the cheek for the individual performing the intubation
- Fourth to administer the drugs
43
What two scales are useful for initial and ongoing assessments of severity of CNS injury?
- Glasgow Coma Scale
| - Modified Glasgow Coma Scale for pediatric patients
44
T or F: Regardless of whether the brain injury is a result of trauma or 2* to global hypoxia, there is Immediate Disruption of the integrity of the BBB resulting in Cerebral edema and diminished neuronal oxygenation
- True
- Children with head trauma may have minimal neurologic abnormalities at time of initial eval
- Increased ICP and neurologic deficits may progressively develop
45
T or F: Brain injuries occur in 2 stages.
-True
Primary insult:
- Occurs at the time of impact
- Results from the biomechanical forces that disrupt the cranium, neural tissue, and vasculature
Secondary insult:
- Parenchymal damage caused by pathologic sequelae subsequent to the primary insult
- Can result from Hypotension, Hypoxia, Cerebral edema, or intracranial HTN/IICP
46
Where should PaCO2 be maintained on a child with cerebral injury?
- Betw. 35 and 40 mmHg
- Routine Mild Hyperventilation (30-35 mmHg): AVIOD!!
- Hyperventilation, even during rescue from acute intracranial HTN, preferentially decreases blood flow to the penumbra of injured neurons surrounding the area of acute brain injury
- Actually worsens flow to the area most in need of perfusion
47
"Calming of the brain"
- Excessive elaboration of excitatory neurotransmitters that are common characteristic of neuronal damage
- IMMEDIATE admin. of OPIOIDS and BENZOdiazepines: titrated to an appropriate level of analgesia and sedation for calming of brain
- Seizure prophylaxis (phenotoin, phenobarbital): in pediatric trauma patient, associated with decreased mortality
48
Basilar Skull Fractures:
Basilar Skull Fractures -Should be considered when caring for children with altered mental status, seizures, or associated trauma requiring surgery
S/S:
- Periorbital ecchymoses (raccoon eyes)
- Retroauricular ecchymosis (Battle's sign)
- Hemotympanum
- Clear rhinorrhea
- Otorrhea
**Nasotracheal intubation or passage of nasogastric tube is best avoided bc these tubes could inadvertently traverse these skull fx's and enter the cranium
49
Subdural Hematoma:
Subdural Hematoma. -D/t rupture of usually VEINS betw. the brain and the dura
- The hematoma compresses the brain tissue
- If hematoma keeps enlarging, a progressive decline in consciousness occurs, possibly even resulting in death
Three types:
1. Acute:
- Most dangerous!!
- Generally caused by a severe head injury
- S/S usually appear immediately
2. Subacute
3. Chronic subdural hematomas
- Both 2 and 3 Develop slower
50
Epidural Hematoma:
Epidural Hematoma -AKA Extradural hematoma
- Occurs when blood vessel (usually an ARTERY) ruptures betw. the dura and the skull
- Blood leaks betw. the dura mater and the skull to form a mass that compresses the brain tissue
- Some people remain conscious, but most become drowsy or comatose from the moment of trauma
- CAN BE DEADLY unless prompt treatment is started (ARTERY!!)
- Infants and children may not demonstrate an altered mental status in early stages after injury
- However, as hematoma expands, it can lead to a LOC, hemiparesis, and pupillary dilatation.
- This deterioration can be quite rapid once a mass effect occurs
51
Epidural Hematoma Treatment:
Epidural Hematoma Treatment -Prompt surgical evacuation!
- Delays are associated with increased morbidity
- Medical therapy directed at Decreasing ICP should be instituted as soon as a diagnosis is suspected
- Children generally recover well after these hemorrhages, although morbidity is usually a reflection of underlying brain injury
52
Acute Subdural Hematoma:
Acute Subdural Hematoma -Almost always traumatic
- Frequently a result of abuse (Shaken Baby Syndrome)
- Infants
53
Shaken Baby Syndrome:
Shaken Baby Syndrome -Baby's head can weigh 1/4th of total body weight
- Neck muscles are still weak
- Any violent shakes will cause the head to fling out of control
- Impact on the brain can be up to 30 times the force of gravity and cause permanent or fatal damage to the baby
- Damage is internal: signs of danger may not be seen until it's too late
- Blood vessels that lead from the brain to the dura membrane are most susceptible to tearing since the subdural space between the brain and the skull is greater for babies
- Nerves in side brain may sever
- If this happens, the brain will swell, cutting off oxygen to the brain in surviving babies: blindness and brain damage may also occur
- Brain stem: vital sensors are located
- If this is severed or damaged, the baby will experience respiratory problems and vomiting
- Optic nerve is often damaged: causes retinal bleeding
- Retinal hemorrhage has an incidence of 50-80% in SBS
- If bilateral, the incidence increases up to 90%
54
S/S of cerebral injury from Shaken Baby Syndrome:
- "Not acting right"
- Poor feeding
- Vomiting
- Irritability
- Lethargy
- Seizure
- Apnea
- Altered LOC
- Visual impairment (retinal hemorrhage)
- Unexplained infant death
**Majority of surviving infants will have some form of neurologic or mental disability: cerebral palsy, or mental retardation, requiring lifelong medical care
55
Bruised areas that are suspect for possible child abuse
- Neck
- Cheeks
- Bottom
- Perineum
56
Physical Abuse definition:
Physical Abuse definition -Physical, mental injury or sexual abuse of a child under the age of 18 years by a person who is responsible for the child's welfare
57
Neglect:
-Care provider responsible for the child either deliberately or by extraordinary inattentiveness permits a child to suffer, or fails to provide conditions generally deemed essential for developing a child's physical, intellectual or emotional capacities
58
Non-Accidental Trauma (NAT): Who is at Risk?
- Children born with physical or developmental disabilities
- Born to single parents who are themselves younger, lesser-educated with less/no prenatal care
- Children with a family history of violence or other abused siblings
***Children 3 and under: HIGHEST RISK for maltreatment and subsequent mortality
- Bruising from physical abuse: tends to be bilateral, widespread and on soft tissue areas (ex. inner thighs, axillary regions) that do not usually come in contact with hard surfaces on falling
- Multiple bruises with different colors, belt whips, finger and hand marks, burns from cigarette butts or hot iron, multiple fractures in different healing stages
- Immersion of children in hot fluids usually present with bilateral burns or equal severity, usually of palms or lower half of the body with sparing of the flexor creases bc the child would be pulling up their legs to avoid the hot fluid
59
What does supplementing GETA with central neuraxial block and/or peripheral nerve blocks result in?
- Pain free awakening
- Postop analgesia WITHOUT potentially deleterious side effects (N/V or altered sensorium) associated with opioids
- Improves pulmonary function in children who have undergone thoracic or upper abdominal surgery
60
How are AMIDES degraded (metabolized)?
- Degraded in liver by cytochrome P450 enzymes
| - Local anesthetics with TWO "i's": lidocaine, bupivacaine, ropivacaine, etc...
61
How are ESTERS metabolized?
- Hydrolyzed primarily by plasma cholinesterases
| - Local anesthetics with ONE "i": procaine, tetracaine, 2-chloroprocaine, etc...
62
T or F: The LA of choice depends on the desired speed of onset, duration of action, and potential toxicity.
True
63
Amides: Bupivacaine
- Most commonly used amide LA for regional blockade in infants and children
- After a single administration, analgesia: up to 4 hours (maybe less in small infants)
- Most commonly used concentration for peripheral nerve block: 0.25%
- Reduced concentration for continuous epidural: 0.0625-0.1%
64
Amides: Ropivacaine
- 0.2%
- Reduced risks of cardiac and neurologic toxicities compared with bupivacaine
- Use of ropivacaine increases in popularity
65
Amides: Mepivacaine & Prilocaine
-Neonates DO NOT metabolize mepivacaine!!!!
- Prilocaine: hepatic metabolism yields O-toluidine
- O-toluidine: can produce methemoglobinemia (redering RBCs less capable of carrying O2)
- Prilocaine unsuitable LA for use of neonates: decreased activity of methemoglobin reductase and increased susceptibility of fetal hemoglobin to oxidization
***Prilocaine is one component of EMLA cream
66
Which LA is NOT metabolized in neonates?
- Mepivacaine
- Controversial, but generally accepted
- The neonatal enzyme systems are adequately developed to metabolize most drugs, with the possible exception of mepivacaine
67
LA Esters
- Plasma cholinesterase activity in infants: decreased c/t adults
- The plasma 1/2 life of ester LA may be prolonges
- 2,3-Chloroprocaine (1.5%): recommended for neonatal regional techniques, including epidural blockade
***Chloroprocaine comes in: 1,2, and 3%...3% easiest to dilute to 1.5%
68
T or F: Pharmacokinetics are different in infants and small children, c/t older children and adults.
- True
- Absorption of drugs: rapid
- The CO and regional tissue blood flow are: Higher
- Epidural space contains: Less fat tissue to buffer the uptake
- Drugs sprayed into the airway are very rapidly absorbed
- Vd of drugs: Larger!
-Plasma levels of Bupivacaine after administration of a standard 2.5 mg/kg dose into epidural space are therefore LOWER in infants than in young children and adults
- The greater Vd also extends the elimination HL
- The extent of protein binding is LESS
- Serum albumin and alpha-1-acid glycoprotein levels are LOW in the neonate
-Bilirubin may further reduce the potential for protein binding
***Caution: when LA is being considered in the JAUNDICED neonate!!
69
Is elimination of amide local anesthetics shortened or prolonged in the neonate c/t the adult?
- Half-time elimination of amide LA is PROLONGED 2-3 times in the neonate
- Approaches adult values after 6 months of age
70
Procaine Max dose and duration of action.
- Max dose: 10 mg/kg
| - DOA: 60-90 min
71
2-Chloroprocaine max dose and DOA
- Max dose: 20 mg/kg
| - DOA: 30-60 min
72
Tetracaine max dose and DOA
- Max dose: 1.5 mg/kg
| - DOA: 180-600 min
73
Lidocaine max dose and DOA
- Max dose: 4.5 mg/kg
| - DOA: 90-200 min (1.5-3.3 hours)
74
Mepivacaine max dose and DOA
- Max dose: 7 mg/kg
| - DOA: 120-240 min (2-4 hours)
75
Bupivacaine max dose and DOA
- Max dose: 2.5 mg/kg
| - DOA: 180-600 min (3-10 hrs)
76
Ropivacaine max dose and DOA
- Max dose: 2 mg/kg
| - DOA: 120-240 min (2-4 hrs)
77
T or F: Doses of amides should be decreased by 30% in infants if less than 6 months of age.
-True
78
What is the duration of LA dependent on?
- Concentration
- Total dose
- Site of administration
- Child's age
79
Dose of LA should be determined by the child's...?
- Age
- Physical status
- Area to be anesthetized
- Weight according to lean body mass
80
Prevention of LA toxicity.
- If a large volume of LA is required for a particular procedure, a diluted concentration should be used
- Doses of AMIDES should be decreased by 30% in infants if less than 6 months of age
-Injection of LA into very vascular areas leads to greater blood concentrations
Remember ICE Block Mnemonic:
```
I = Intercostal (greatest order of uptake)
C = Caudal
E = Epidural
Block = peripheral nerve blocks (brachial, femoral, sciatic, etc.)
```
81
Toxicity of LA's
- Major toxic effects of LA: CV and CNS (LA cross BBB readily)
- Lower threshold for cardiac toxicity with bupivacaine: cardiac and CNS toxicity may occur virtually simultaneously in infants and children
- GETA with volatile anesthetics: may obscure the signs of CNS toxicity until devastating CV effects are apparent
CNS/CV signs of toxicity:
-Circumoral paresthesia, lightheadedness, tinnitus, slurred speech, muscle twitching, seizures, resp. depression/arrest, ventricular arrhythmias/cardiac arrest
Bupivacaine:
- Has a particular affinity for Na+, K+, and Ca++ channels
- Makes RESUSCITATION effort DIFFICULT after a toxic dose
- Highly bound to plasma proteins (alpha-1-acid glycoprotein)
- Concentration of albumin and a1-acid glycoprotein are less in neonates: INCREASED FREE (UNBOUND) FRACTION OF THE LA THAT PRODUCES TOXICITY)
82
Treatment of Toxic Reactions.
- Progression from Prodromal signs to CV collapse may be rapid
- Resuscitation: ABC's: patent airway, supplemental O2, reestablishing circulation and normal cardiac rhythm
- Midazolam: 0.05-0.2 mg/kg
- Thiopental: 2-3 mg/kg
- Both will prevent or terminate seizure activity
- Cardiac Arrest: THINK INTRALIPIDS!!!
- 1.5 ml/kg of 20% intravenous lipid emulsion
- Very effective for resuscitation of cardiac arrest with bupivacaine toxicity
- Mechanism: poorly understood...possibly binds to free fractions of bupivacaine?!
- Dose can be repeated: max of 3 ml/kg
- Maintenance infusion rate: 0.25 ml/kg/MIN until circulation is restored
83
Is a lipid emulsion of PROPOFOL ok to give for LA toxicity?
-NO!!
Supportive treatment should include:
- IV fluid loading: 10-20 ml/kg of isotonic crystalloid
- Peripheral vasopressors: phenylephrine, norepi
- Antiarrhythmic drugs
- Phenytoin
- ECMO (extracorporeal membrane oxygenation)
- etc...
84
Central Neuraxial Blockade: Differences between adults vs. children.
- Conus Medullaris (terminus of the SC) in neonates/infants (up to 1 year) location: at L3 (adults: L1)
- Lumbar puncture for subarachnoid block/spinal in neonates/infants is performed at: L4-L5 and L5-S1 to avoid needle injury to the SC
85
Infant's sacrum vs. Adult's sacrum
Tip of SC in a Neonate ends at: L3...does not achieve normal adult position (L1-2) until approximately 1 YEAR of AGE!!
- Neonatal sacrum is NARROWER and FLATTER than adults
- Approach to the subarachnoid space from the caudal canal is much more likely, so the needle must NOT BE ADVANCED deeply in neonates
86
What does the presence of a Deep Sacral Dimple possibly associated with?
- Spina Bifida Occulta
- Greatly increases the possibility of dural puncture
- Caudal Block is CONTRAINDICATED!!!
87
Subarachnoid Blockade: Differences betw. Adults vs. Children.
- CSF volume as a percentage of body weight: greater in infants and young children than in adults
- May account in part for the comparatively larger doses of LA requirement for surgical anesthesia with subarachnoid block in infants and young children
- CSF turnover rate: Considerably GREATER in infants and children
- Much briefer duration of subarachnoid block with any given agent c/t adults
- These anatomic differences necessitate meticulous attn. to detail to achieve successful and uncomplicated spinal and epidural anesthesia
- In contrast to older children and adults, neuraxial blocks in infants and small children: hemodynamic stability, even when the level of block reaches the upper thoracic dermatomes
- Infants: PNS is stronger than SNS
- HR appears to attenuate and clinically significant BP changes DO NOT occur in young infants after a subarachnoid block
88
Caudal Epidural Anesthesia:
Caudal Epidural Anesthesia -Place the anesthetized pt. in a lateral decubitus position with spine and shoulder in neutral curvature
- Palpate cornua of caral hiatus: these are 2 bony ridges that are easily palpated, about 0.5-1 cm apart...often found just at the beginning of the crease of the buttocks
- Appropriate insertion spot: slightly more caudal from the palpated sacral corni
- Prep site with Iodine, Chlorohexadine, and alcohol pads (wiping TOWARDS buttocks)
- Have your prepared 22 G IV catheter with a pig-tail and a LA-filled syringe readily available
- Don sterile gloves, palpate injection site and insert needle BEVEL facing DOWNWARD: initially directed cephalad at a 45° angle
- The needle advances through skin until it "pops" through the sacrococcygeal ligament into the caudal canal, which is contiguous with the epidural space
- If bone is encountered before the sacrococcygeal ligament, needle should be withdrawn several mm's, the angle with the skin decreased (~30°), and again gently advanced until ligament is pierced
- As the needle is farther advanced, the angle of the needle should be decreased and nearly parallel to the plane of the child's back
- The IV catheter stays in place, while the needle is removed. The pigtail-syringe filled with LA will be attached
- Once a negative aspiration for both blood or CSF is confirmed, a test dose of LA is administered
- If neither hemodynamic nor ECG changes are evident after test dose: remainder of dose of LA for a single-shot caudal anesthesia should be SLOWLY injected with intermittent aspiration
- IO injection of LA: very rapid uptake (similar to direct IV injection)
- Remove the IV catheter, wipe off the site and place a bandaid over it
89
Selection of Drug for Epidural Blockade.
-Drug dose required for epidural blockade to a given dermatomal level: depends on VOLUME (not concentration!!) of the LA and the volume of the epidural space, which may change with age
Concentration of LA: based on the desired density of the block and on the risk of toxicity:
- Less dense for post-op analgesia
- More dense for intra-op; anesthesia
90
How much Volume for an Epidural Blockade?
- 1 ml/kg (up to 20 ml) of 0.125% bupivacaine w/epi 1:200,000
- Generally provides a sensory block with minimal motor block up to T4-T6 level
- After initial block is established, a continuous infusion should maintain the block at a constant level
91
Where does the spinal cord end in the neonate?
-At the lower border of L3
92
A neonate is underlying a surgical procedure with the use of a spinal blockade. What sign would indicate a "high" or "total" spinal?
- Decreasing O2 sat is the earliest sign of a high or total spinal in the neonate
- A high/total spinal, produced either with a primary spinal technique or 2* to an attempted epidural presents as: resp. insufficiency rather than hypotension owing to a relatively immature SNS system in the neonate
- With an immature SNS, the CV parameters are remarkably stable in the neonate with a high or total spinal
93
What is the max dose of 0.25% bupivacaine that should be used for pediatric caudal anesthesia?
-Bupivacaine 0.25% at a volume of 1 ml/kg up to a max of 25 ml can provide 3-6 hours of anesthesia for surgical procedures below the level of the diaphragm
94
For a pediatric pt. weighing 2-20 kg, what volume (ml/kg) of 0.25% bupivacaine should be administered caudally for a block to L1 or T12? To T10? To T4 or T5?
- L1 to T12: 0.35 ml/kg
- For T10: 0.5-0.75 ml/kg
- For T4-T5: 0.75-1.25 ml/kg
95
What is the appropriate volume for a pediatric epidural blood patch?
- In child who is awake: stop blood infusion once child feels discomfort of pressure in the back
- Anesthetized Pt: no more than 0.3 ml/kg of blood should be injected into the epidural space
