Transcript blood pressure thrust

‫به نام خالق انسان و آب وهستی‬
Preoperative Nurse Anesthesia
assessment and preparation of pediatric patient
Dr N.Nasseh
cardiac anesthesiologist
Booalisina Hospital ( Qazvin University of Medical Science)
• The American Society of Anesthesiologists (ASA) has
published a practice advisory that suggests a pre anesthesia
visit should include the following:
▪ An interview with the patient or guardian to establish a medical,
anesthesia and medication history
▪ An appropriate physical examination
▪ Indicated diagnostic testing
▪ Review of diagnostic data (laboratory, electrocardiogram,
radiographs, consultations)
▪ Assignment of an ASA physical status score (ASA-PS)
American Society of Anesthesiologists Physical Status
Classification
•
ASA 1 Healthy patient without organic, biochemical, or psychiatric disease.
•
ASA 2 A patient with mild systemic disease,
e.g., mild asthma or well-controlled HTN.
No significant impact on daily activity. Unlikely impact on anesthesia and surgery.
•
ASA 3 Significant or severe systemic disease that limits normal activity,
e.g., renal failure on dialysis OR class 2 CHF.
Significant impact on daily activity. Likely impact on anesthesia and surgery.
•
ASA 4 Severe disease that is a constant threat to life OR requires intensive therapy,
e.g., acute MI , respiratory failure requiring MV.
Serious limitation of daily activity. Major impact on anesthesia and surgery.
•
ASA 5 Moribund patient who is likely to die in the next 24 hours with or without
surgery.
•
ASA 6 Brain-dead organ donor.
*“E” added to the above classifications indicates emergency surgery,
The preoperative evaluation of a pediatric patient
differs from that of an adult in a number of respects.
•
Age and weight of the child are extremely important as equipment such as
laryngoscopes, endotracheal tubes, masks, and intravenous fluid setups are
based on the age and size of the child.
•
Pharmacologic drugs are dosed based on weight, and accuracy is critical to
avoid under- and over dosage.
•
A history of prematurity and any sequelae of prematurity such as cerebral
palsy, chronic lung disease and apnea and bradycardia are important .
•
If the child has a genetic or dysmorphic syndrome, ====> Evaluation of
potential impact on the anesthesia including craniofacial or cervical spine
abnormalities ====> ↑difficult endotracheal intubation.
•
Family history of MH, patient history of MH, and congenital myopathies OR
presence of muscular dystrophies.
•
The patient and parent should be questioned about the presence
or recent history of congestion, cough, fever, vomiting or diarrhea,
which may impact the decision to proceed with an elective
procedure.
• Vital signs, including pulse, respiratory rate, temperature, and blood
pressure, should be measured.
•
In addition, a room air pulse oximeter check is important to screen
for occult cardiac or pulmonary disease.
RECENT UPPER RESPIRATORY TRACT INFECTION
• A child with a current upper respiratory infection (or recovering from such
an infection) is at increased risk to develop laryngospasm, bronchospasm,
oxygen desaturation, post extubation croup, and postoperative atelectasis.
• The patient should be examined for nasal congestion, cough, wheezing,
and fever.
• Signs of lower respiratory tract infection require cancellation of elective
surgery
• Minor surgery being performed in the face of URI, especially ear, nose,
and throat (ENT) procedures when URI is frequent and the surgery will
often decrease the frequency of these infections.
•
Elective Major surgery (i.e., intra-abdominal, intrathoracic, cardiac) is
usually postponed for 2 to 6 weeks
PREOPERATIVE FASTING GUIDELINES
Pre-OP NPO time
Solid foods
6-8 hour
milk, infant formula
6 hours
breast milk
4 hours
clear liquids
2 hours
PREMEDICATION
 The most widely used premedication in North America is midazolam.
 It can be administered via oral, intranasal, rectal, and intramuscular
routes.
 Midazolam 0.5 to 0.75 mg/kg, (PO)provides adequate anxiolysis and
sedation approximately 20 minutes after oral administration.
 Oral midazolam in doses of 0.25 to 0.5 mg/kg does not appear to lengthen
recovery room time
 Midazolam can be reversed with Flumazenil.(The initial recommended
dose in children is 0.05 mg/kg given intravenously titrated up to 1.0 mg
total.)
 Children who are 2 to 6 years old who have had previous surgery, no
preoperative tour or education, or who fail to interact positively with
health care providers should be premedicated.
Premedication—Drugs Options and Doses
ELIMINATION
HALF-LIFE
T½(hr)
MEDICATION
ROUTE
DOSE (mg/kg)
TIME TO
ONSET (min)
Midazolam
Oral
0.25–1.0
10
2
Intranasal
0.2–0.3
<10
2–3
Rectal
0.3–1.0
10
2–3
Oral
3.0–6.0
10
2–3
Intranasal
3.0–5.0
<10
3
Rectal
5.0–6.0
20–30
3
Oral
0.002–0.004
45
8–12
Ketamine
Clonidine
Differences between the adult and pediatric airways
INFANT AIRWAY
SIGNIFICANCE
Obligate nose breathers, narrow nares
Infants can breathe only through their
noses, which can become easily obstructed
by secretions.
Large tongue
Tongue may obstruct airway and make
laryngoscopy and intubation difficult.
Large occiput
Sniffing position may be achieved with roll
under shoulder.
Glottis located at C3 in premature babies,
C3-C4 in newborns, and C5 in adults
Larynx appears more anterior; cricoid
pressure frequently helps with laryngeal
visualization.
Larynx and trachea are funnel shaped
Narrowest part of the trachea is at the vocal
cords; the patient should have an ETT leak of
<30 cm H 2 O to prevent excessive pressure
on the tracheal mucosa, barotrauma.
Vocal cords slant anteriorly
Insertion of ETT may be more difficult.
Duke's Anesthesia Secrets, Fifth Edition James C. Duke , Brian M. Keech
Differences in the adult and pediatric pulmonary systems
PEDIATRIC PULMONARY SYSTEM
SIGNIFICANCE
Decreased, smaller alveoli
Thirteen-fold growth in number of alveoli
between birth and 6 years; threefold
growth in size of alveoli between 6 years
and adulthood
Decreased lung compliance
Increased likelihood of airway collapse
Increased airway resistance, vulnerability
to smaller airways
Increased work of breathing and disease
affecting small airways
Horizontal ribs, pliable ribs and cartilage
Inefficient chest wall mechanics
Less type 1, high-oxidative muscle
Babies tire more easily
Decreased total lung capacity, faster
respiratory and metabolic rate
Quicker desaturation
Higher closing volumes
Increased dead-space ventilation
Duke's Anesthesia Secrets, Fifth Edition James C. Duke , Brian M. Keech
Cardiovascular system in a child
– Newborns are unable to increase cardiac output (CO) by increasing
contractility; they increase CO only by increasing heart rate.
– Infants have an immature baroreceptor reflex and limited ability to
compensate for hypotension by increasing heart rate ===> Therefore
they are more susceptible to the cardiac depressant effects of volatile
anesthetics and most intravenous anesthetics.
– Infants have increased vagal tone and are prone to bradycardia.
– The three major causes of bradycardia are :
• hypoxia (most commonly),
• vagal stimulation (e.g., laryngoscopy),
• volatile anesthetics.
– Bradycardia decreases CO.
Normal vital signs in children
AGE (YEARS)
HR
RR
SBP
DPB
<1
120–160
30–60
60–95
35–69
1–3
90–140
24–40
95–105
50–65
3–5
75–110
18–30
95–110
50–65
8–12
75–100
18–30
90–110
57–71
12–16
60–90
12–16
112–130
60–80
DBP, Diastolic blood pressure; HR, heart rate; RR, respiratory rate; SBP, systolic blood pressure.
A good rule of thumb is normal BP = 80 mm Hg + 2 × age.
Duke's Anesthesia Secrets, Fifth Edition James C. Duke , Brian M. Keech
Induction of Anesthesia in children
 Inhalational induction
•
•
•
is the most common induction technique in children younger than 10 years of
age who do not have intravenous (IV) access.
The child is asked to breathe a mixture of 70% nitrous oxide (N 2 O) and 30%
oxygen for approximately 1 minute; sevoflurane is then added.
The sevoflurane concentration can be increased slowly or rapidly.
 IV induction
– is used in a child who already has an IV line in place and in children older than
10 years.
– Typical medications used in children are
• propofol, 2 to 3 mg/kg,
etomidate, 0.2 to 0.3 mg/kg
• ketamine, 2 to 5 mg/kg,
methohexital, 1 to 2 mg/kg
– EMLA cream (eutectic mixture of local anesthesia lidocaine 2.5%
and prilocaine 2.5%) applied at least 60 minutes before starting the IV
infusion makes this an a traumatic procedure
The appropriate endotracheal tube size
AGE
SIZE—INTERNAL DIAMETER (mm)
Newborns
3.0–3.5
Newborn–12 months
3.5–4.0
12–18 months
4.0
2 years
4.5
>2 years
ETT size = (16 + age)/4
Duke's Anesthesia Secrets, Fifth Edition James C. Duke , Brian M. Keech
Can cuffed ETTs be used in children?
 Common teaching was that cuffed ETTs should not be used in children <8
years old.
 The reasons are twofold:
1. Avoid trauma to the narrowest part of the pediatric airway—the
cricoid.
2. Allow a bigger un cuffed ETT to be passed, which would decrease the
work of breathing .
 Tracheal mucosal inflammation and injury are related to a number of
factors, including duration of intubation and number of intubation
attempts.
 Cuffed ETTs can be used in children and neonates.
 Of course, the cuff takes up space, thus limiting the size of the ETT.
 Use the cuffed tube one half size smaller than the appropriate uncuffed
tube.
 The advantages of cuffed ETTs are that they avoid repeat laryngoscopy
decrease the number of intubation attempts and may allow use of lower
fresh gas flows. and provide better protection against aspiration
Appropriate-size laryngeal mask airway (LMA)
SIZE OF CHILD
LMA SIZE
Neonates up to 5 kg
1
Infants 5–10 kg
Children 10–20 kg
2
Children 20–30 mg
Children/small adults >30 kg
3
Children/adults >70 kg
4
Children/adults >80 kg
5
Perioperative fluid management in children
– Maintenance is calculated as follows:
• Infant <10kg :
• 10 to 20 kg :
• Child >20 kg :
4 ml/kg/hr
40 ml/hr + 2 ml/kg/hr for every kg over 10
60 ml/hr + 1 ml/kg/hr for every kg over 20
–
Estimated fluid deficit (EFD) should be calculated and replaced as
follows:
• EFD = maintenance × hours since last oral intake
–
All EFDs should be replaced for major cases. For minor cases, 10 to
20 ml/kg of a balanced salt solution (BSS) with or without glucose is
usually adequate.
Estimated blood volume (EBV) and acceptable blood loss (ABL) should
be calculated for every case.
–
The most common replacement fluid used in children
 A balanced salt solution, such as lactated Ringer with glucose (D 5 LR) or
without glucose (LR) is recommended.
 Hypoglycemia is rare in healthy children undergoing minimally invasive
procedures, and administration of 5% glucose-containing solutions results
in hyperglycemia in the majority of children.
 Others still use 5% glucose solutions for maintenance but recommend
non-glucose–containing BSS for third space or blood loss.
 In major operations it is prudent to check serial glucose levels and avoid
hyperglycemia or hypoglycemia.
Estimated blood volume in children
AGE
EBV (ml/kg)
Neonate
90
Infant up to 1 year old
80
Older than 1 year
70
EBV, Estimated blood volume.
Acceptable blood loss
ABL=[EBV×(pt hct−lowest acceptable hct)]/average hct]
ABL = acceptable blood loss,
pt = patient,
EBV = estimated blood volume,
hct = hematocrit
 The lowest acceptable hematocrit varies with circumstances.

Blood transfusion is usually considered when the hematocrit is <21% to
25%. If significant blood loss is anticipated, transfusion may need to be
started earlier.
Example
A 4-month-old infant is scheduled for craniofacial reconstruction.
He is otherwise healthy, and his last oral intake was 6 hours before arriving
in the OR;
• weight = 6 kg, preoperative hct = 33%, lowest acceptable hct = 25%.

Maintenance = weight × 4 ml/hr = 24 ml/hr
 EBV = weight × 80 ml/kg = 480 ml
 ABL = [EBV × (pt hct − lowest acceptable hct)]/average hct]
= [480 × (33 − 25)]/29 = 132 ml
Regional anesthesia in children
 Caudal epidural block is the most common regional technique.
 It is usually performed in an anesthetized child and provides
intraoperative and postoperative analgesia.
 It is used most commonly for surgery of the lower extremities, perineum,
and lower abdomen.
 Bupivacaine (0.125% to 0.25%) or ropivacaine 0.2% are most commonly
used.
common postoperative complications
 Postoperative nausea and vomiting (PONV)
 Laryngospasm and stridor
Emergence agitation
Postoperative nausea and vomiting (PONV)


is the most common cause of delayed discharge or unplanned admission.
Factors associated with PONV in children include:
o
o
o
o
o
o
o
o
o
o




age >6 years,
length of surgery >20 minutes
previous history of PONV
eye surgery
Inner ear procedures
history of motion sickness
tonsillectomy/adenoidectomy
preoperative nausea or anxiety
hypoglycemia
use of opioids and N O
2
The best treatment for PONV is prevention.
Prophylactic administration of an antiemetic should be considered for
patients at high risk for PONV.
Avoiding opioids decreases the incidence of PONV as long as pain relief is
adequate (e.g., patient has a caudal block).
Management includes administering IV fluid, limiting oral intake, and
administering dexamethasone, metoclopramide, or ondansetron.
Laryngospasm and stridor
 are more common in children than in adults.
 Management for laryngospasm includes
• oxygen
• positive pressure ventilation
• jaw thrust
• succinylcholine
• propofol
• re-intubation if necessary
 Stridor is usually treated with humidified oxygen, steroids,
and racemic epinephrine.
PAIN Management in children
 Analgesic Drugs
• Analgesic drugs used for pain
control in children include
– Acetaminophen
– NSAIDs
– Opioids
• they can be administered by
an oral, IM or IV route.
• The most common opioids
used in pediatric anesthesia
are fentanyl and morphine.
– Side effects include
sedation, respiratory
depression, pruritus, and
nausea/vomiting
 Regional Anesthesia
• for intraoperative and post-op pain
control provides excellent analgesia
with minimal side effects and
decreases the requirement for opioid
and nonopioid pain relievers.
• caudal injection with local anesthetic
is most commonly used for surgery
on or below the umbilicus.
• Nerve block (brachial plexus,
ilioinguinal nerve, femoral nerve,,
ankle, penile blocks &….)
• Spinal anesthesia has also been used
as the sole anesthetic or in
combination with a general
anesthetic for a variety of cases
KEY POINTS
- Infants may be difficult to intubate because they have a
more anterior larynx, relatively large tongues, and a floppy
epiglottis. The narrowest part of the larynx has been found to
be below the vocal cords at the cricoid cartilage.
- Children de-saturate more rapidly than adults because of
increased metabolic rate, increased dead space, inefficient
chest wall mechanics and, in neonates, immature alveoli.
- Premedication with midazolam has been shown to be
superior in decreasing a child's anxiety when compared with a
placebo or parental presence at the time of induction.
Solids are prohibited within 6 to 8 hours of surgery (generally
after midnight), formula within 6 hours, breast milk within 4
hours of surgery, and clear liquids within 2 hours of surgery.
-Mask induction of general anesthesia remains the most
common induction technique for pediatric anesthesia the United
States. There is no question that inhalation induction of
anesthesia is safe, but the incidence of bradycardia,
hypotension, and cardiac arrest during this form of induction is
higher in infants younger than age 1 year than in older children
and adults.
-Propofol is the most widely used intravenous agent for
induction and maintenance of anesthesia or sedation in children
-Prolonged infusion in the intensive care environment has been
linked to acidosis, heart failure, and a number of fatalities.
-Postoperative nausea and vomiting is particularly prominent
after certain surgeries such as orchidopexy, strabismus surgery,
and tonsillectomy. There is no single therapy that is universally
accepted as safe and effective.
-Several formulas have been used for tube selection in children
older than age 1 year, the most common being (16 + age)/4.
- The most commonly used form of regional anesthesia in
children is the caudal block. This technique can provide
postoperative analgesia following a wide variety of lower
abdominal and genitourinary surgical procedures.
Refference
1. Basics of ANESTHESIA Sixth Edition Ronald D. Miller, and Manuel Pardo,
2. Duke's Anesthesia Secrets, Fifth Edition
James C. Duke and Brian M. Keech
3. Clinical Anesthesia Sixth Edition Paul G. Barash, Bruce F. Cullen, Robert K.
Stoelting, Michael Cahalan, M. Christine Stock
Thank you for your attention