SEE exam Questions Flashcards
What is placenta accreta?
adherence to the myometrium WITHOUT invasion of or passage through uterine muscle
What is placenta increta?
INVADES and is confined to the myometrium
What is placenta percreta?
INVADES and may PENETRATE the myometrium, the uterine serosa, or other pelvic structures
If mom has had a previous c-section or had uterine trauma, she is at risk for developing placenta _________.
accreta; the more c-sections the > the incidence.
Are the MRI and ultrasonography good indicators for the diagnosis of placenta accreta?
NO; they are poor
What is the MOST common indication for obstetric hysterectomy?
placenta accreta; most cases require cesarean or post partum hysterectomy without delay
What is the key anesthetic consideration for intra-op management during a case involving placenta abnormalities?
VOLUME
When is the APGAR scoring performed?
at 1 minute and again at 5 minutes
An APGAR of _______ is considered normal.
8-10
An APGAR of _______ is considered moderate distress or impairment.
4-7
An APGAR of _______ is considered to indicate need for immediate resuscitation.
0-3
How many parameters does the APGAR score include?
5
What are the 5 parameters for APGAR scores?
HR, respiratory effort, muscle tone, reflex irritability (nasal catheter, suctioning, etc), and color
How do you score an infant’s APGAR?
Either give 0, 1, or 2 on each parameter.
HR: none is 0; 100 is 2
resp effort: none is 0; irregular or shallow is 1; robust or crying is 2
muscle tone: none is 0; some flexion is 1; active movement is 2
reflex irritability: no response is 0; grimace is 1; active coughing or sneezing is 2
color: cyanotic is 0; acrocyanotic (trunk pink, ext blue) is 1; pink is 2
When is hyperreflexia seen?
in 85% of spinal cord injury patients with lesions above T5; occurs when the hypothalamus and brainstem can no longer modulate segmental spinal sympathetic nerves and thereby inhibit their output–> acute phase has diminished sympathetic activity–> sympathetic activity returning to viable cord below the lesion is isolated from upper inhibitory control
What are signs of hyperreflexia?
paroxysmal HTN, bradycardia, and cardiac dysrhythmias in response to stimulation below the level of transection (bladder cath, childbirth)
Is hyperreflexia seen immediately after injury?
No, it is not seen until the spinal shock phase has passed (usually after 2 to 3 weeks of spinal cord injury)
How do you treat autonomic hyperreflexia?
remove stimulus, deepen anesthesia, and administer direct acting vasodilators (Na nitroprusside is reliable/rapid/titratable, but continuous monitoring of cyanide toxicity; Nifedipine can be sublingual/quick onset/relatively short duration, but unreliable and delayed absorption; BEST is NICARDIPINE which is primary arterial dilator, whereas Na Nitroprusside is veno and arterial); bradycardia is treated with atropine or glyco
What happens to untreated autonomic hyperreflexia?
HTN crisis may progress to seizures, intracranial hemorrhage, or MI
What spinal lesions are usually associated with autonomic hyperreflexia?
lesions above T5 tend to be associated with AH because the majority of spinal sympathetic efferents arise below this level; below T10 are NOT associated with AH
What are some side effects seen after fasciculations caused by succinylcholine administration?
myalgia, myoglobinemia (RARE), elevated intragastric pressure, elevated ICP
When should a burn patient not receive a dose of succinylcholine?
after 24 hours following the burn
Why does fasciculation occur after administration of succinylcholine?
b\c is it a depolarizing muscle blocker; AcH-like drug binds with the nicotinic receptor at skeletal muscle nerve endings and causing depolarization
How many cervical vertebrae are there?
7
How many thoracic vertebrae are there?
12
How many lumbar vertebrae are there?
5
How many sacral vertebrae are there?
5
How many coccygeal vertebrae are there?
4
What is P50 and what is the normal #?
P50 is the partial pressure of oxygen at which Hgb is 50% saturated by oxygen; normal is 26-27mmHg
Is oxygen release from Hgb to the tissues increased or decreased by acidosis? by alkalosis?
increased by acidosis d\t curve shift to the right–> facilitates unloading of oxygen at the tissues; OPPOSITE for alkalosis
How much oxygen is dissolved in arterial blood if PaO2 is 90mmHg?
formula is: dissolved oxygen= 0.003 x PO2 (units are ml O2/100mL blood)…. so 90 x 0.003=0.270mlO2/dl
Calculate the increase in dissolved oxygen in the arterial blood if PaO2 increases from 50mmHg to 300mmHg.
dissolved O2 (PaO2, 50mmHg)= 0.003 x 50= 0.15 dissolved O2 (PaO2, 300mmHg)= 0.003 x 300= 0.90 So.... 0.90 minus 0.15= 0.75mlO2/100mL increase
Whose law permits the amount of dissolved oxygen in the blood to be calculated?
Henry’s law; gases dissolve better in colder liquids
To calculate the amount of oxygen bound to hemoglobin, you need to know:
1) amount of oxygen carried by each gram of fully saturated Hgb?
2) normal concentration of Hgb?
3) the percent saturation? 90%
1) amount of oxygen carried by each gram of fully saturated Hgb= 1.34mlO2 per g Hgb
2) normal concentration of Hgb= 15g Hgb per 100mL blood
3) the percent saturation? 90%= 90/100= 0.9
Calculate the total amount of O2 bound to Hgb when it is 90% saturated (assume normal Hgb concentration).
O2-Hgb= (1.34mlO2/gHgb) x (15g Hgb/100mL blood) x (0.9)= 18.1mLO2/100mL blood= 18.1 mL O2/dl bound
Remember that when blood is 70% and 90% saturated, respectively, the PO2 can be estimated to be at ____ and ____mmHg.
40 and 60mmHg PO2 at 70% and 90% saturation
Calculate the PO2 when blood is 90% saturated (assume normal Hgb concentration).
remember that even if you are not given PO2, you can estimate off of saturation (40 and 60 at 70% and 90%)…. so 0.003 x 60= 0.18ml O2/dl
Calculate the total amount of O2 carried by blood when it is 90% saturated (assume normal Hgb concentration).
to get the total amount carried you have to add the amount of oxygen bound to Hgb to the amount dissolved in blood: so 90% gives you PO2 of 60…. 60 x 0.003=0.18; next step is 1.34 x 15/100 x 0.9= 18.1 bound; next add 0.18 + 18.1= 18.28mL O2/100mL blood
What is the formula for blood oxygen content?
O2 content= (PaO2 x 0.003) + (Hb content[1.34] x Hg [15] x O2 saturation %)
What is the Parkland formula?
prescribes fluids based on % of body surface area burned: volume over 24 hours= kg x 4 x %BSA burned; half of this volume in first 8 hours, 25 % next 8 hours, 25 % final 8 hours
What are some common errors in the use of the t-test?
multiple application without correction; use of independent groups form for paired data and vice versa; use for ordinal data
What is the purpose of a t-test?
in independent groups: to test the difference between the means of two independent groups
in dependent samples: to test the difference between dependent, paired samples outcome
A statistical examination of two population means. A two-sample t-test examines whether two samples are different and is commonly used when the variances of two normal distributions are unknown and when an experiment uses a small sample size. For example, a t-test could be used to compare the average floor routine score of the U.S. women’s Olympic gymnastic team to the average floor routine score of China’s women’s team. –> helps determine p value
What is a dependent variable?
a DV is the object of the study, or the variable being measured
What is the difference in dependent and independent variables?
a DV is the variable being measured…. the IV is the one that affects the dependent variable and is presumed to cause or influence it
In a study of a new IV drug that may have fewer cardio effects than thiopental during induction of pediatric patients….. separated into two groups, the thiopental group and the new drug group; BP, HR and rhythm are measured by a dedicated observer who is unaware of the two groups. What are the independent and dependent variables?
The DV is the cardio parameters: BP, HR, etc
The IV is the drug, either thiopental or new drug
What positions can be used for a popliteal block?
lateral, supine, or prone
What nerve does the popliteal block cover?
sciatic
What is the landmarks for a popliteal block?
place probe in popliteal fossa and identify the nerve, popliteal vein, and popliteal artery–> at this level it is only the tibial component, but as you scan up you will see the tibial and peroneal which then join to form the sciatic
In respect to positioning, where is tibial and peroneal components of the sciatic nerve located?
tibial is medial and peroneal is lateral
When performing a popliteal block, what muscles can be seen on either side?
semitendonosis and semimembranous muscle is seen on the medial side; on the lateral side you see the biceps femoris (long and short heads)
Where does the sciatic nerve innervate?
Sciatic nerve supplies motor and sensory innervation to the posterior aspect of the thigh as well as the entire lower leg, except for medial leg … Which is supplied by the saphenous nerve (terminal branch of the femoral nerve)
* Requires adequate setup because this nerve resists local anesthetic penetration, leading to longer block onset times
Where does the sciatic nerve arise from?
Arises from the ventral rami of L4 through S3, which forms most of the sacral plexus (L4-S4)
- It is actually two nerves in close apposition, the tibial and common peroneal (fibular) nerves
- These nerves usually do not separate until the mid thigh, although separation as proximal as the pelvis occurs in about 12% of patients
- Sciatic leaves the pelvis via the greater sciatic foramen amd continues distally toward the posterior thigh between the greater trochanter and ischial tuberosity
- Although it does not inner age any muscles in the gluteal region, it supplies motor innervation to the posterior thigh muscles as well as all muscles of the leg and foot
- Provides sensory innervation to the skin of most of the leg and foot
What is the classical approach to blocking the sciatic nerve?
Labat’s sciatic nerve block: targeting it in the gluteal region; has advantage of also blocking posterior femoral cutaneous nerve, which is important when tourniquets are on for long periods
What are the landmarks for Labat’s sciatic nerve block?
- Patient is placed in lateral decubitus (operative side up) and the leg is flexed at the knee (if patient is unable to flex the knee, the leg should be extended at the hip as far as possible without discomfort)
- Draw a line between the greater trochanter to the posterior superior iliac spine (PSIS)
- Draw second line from greater trochanter to the patients sacral hiatus
- Determine the point of needle insertion by drawing a line perpendicular from the midpoint of the first line to its intersection with the second line
- A fourth line can be drawn along the “furrow” formed by the medial edge of the gluteus Maximus muscle and the long head of the biceps femoris muscle (the furrow represents the course of the sciatic nerve towards the lower leg
- The triangle formed by the 1st, 2nd, and 4th lines further defines initial needle placement, and subsequent adjustments of the needle within the triangle to improve stimulation
Where is norepinephrine synthesized?
Cytoplasm of sympathetic postganglionic nerve endings and stored in vesicles
How is the action of norepinephrine terminated?
Primarily by reputable into the postganglionic nerve terminals (which is inhibited by tricyclic antidepressants); but also by diffusion from receptor sites, or metabolism by MAO or COMT
How is norepinephrine and ultimately epinephrine synthesized?
Hydroxylation of tyrosine to dopa is the rate limiting step; norepinephrine can be converted into epinephrine in the adrenal medulla: phenylalanine to tyrosine in liver–> dopa to dopamine in postganglionic cytoplasm–> norepinephrine to epinephrine in adrenal medulla
Before how many weeks old is considered to be a premature infant?
Before 37 weeks
What is more common, omphalocele or gastroschisis?
Omphalocele ….. 1:5,000 vs 1:15,000
Where is an omphalocele located?
Base of the umbilicus
Where is a gastroschisis located?
Lateral to umbilicus
Which has a sac, omphalocele or gastroschisis?
Omphalocele