ACE 8A Flashcards
Regarding tocolytics: What class of drugs are contraindicated for additional tocolysis when magnesium sulfate is already being used?
Calcium channel blockers
Regarding tocolytics: What are the maternal side effects of calcium-channel blocking drugs?
- Transient hypotension (with sequelae such as nausea, dizziness)
- Flushing
- HA
Regarding tocolytics: What class are NOT associated with fetal/neonatal side effects?
Calcium channel blocking drugs
Name four classes of tocolytics.
- Calcium-channel blockers
- Cyclooxygenase inhibitors (NSAIDs)
- Beta-agonists
- Magnesium
Regarding tocolytics: What conditions are contraindications for NSAID use as tocolytics?
A lot of common sense things here….
- Significant renal/hepatic impairment
- PUD
- coag disorders/thrombocytopenia
- NSAID-sensitive asthma
Regarding tocolytics: What are the fetal/neonatal side effects of NSAIDs?
- PDA constriction
- pulmonary HTN
- reversible renal impairment
- oligohydramnios (2/2 above renal impairment)
- hyperbilirubinemia
- +/- intraventricular hemorrhage (data is mixed)
- +/-NEC (data is mixed)
Regarding tocolytics: What maternal conditions are contraindications to beta-agonist use?
- Poorly controlled DM
- Poorly controlled thyroid dz
- cardiac dysrhythmias
Regarding tocolytics: What are the fetal side effects of maternal beta-agonist use?
- tachycardia
- hyperinsulinemia
- hyperglycemia
- myocardial and septal hypertrophy
- myocardial ischemia
f c0-9p90-Regarding tocolytics: What are the neonatal side effects of maternal beta-agonist use?
This is actually different from the fetal side effects in many ways:
- tachycardia (same as fetal)
- hypoglycemia
- hypocalcemia
- hyperbilirubinemia
- hypotension
- intraventricular hemorrhage
Regarding tocolytics: What are the fetal/neonatal side effects of maternal magnesium sulfate use?
- Lethargy
- hypotonia
- respiratory depression
- demineralization (with prolonged use)
Regarding tocolytics: What maternal conditions are contraindications to magnesium sulfate use?
- Myasthenia gravis
- Myotonic dystrophy
Regarding tocolytics: What are the maternal side effects of magnesium sulfate?
- Flushing
- lethargy
- HA
- weakness
- diploplia
- dry mouth
- pulmonary edema
- cardiac arrest
What valvular anomaly is associated with constriction of the ductus arteriosus in a fetus?
Tricuspid regurgitation
What percentage of fetal cardiac output comes out of the right ventricle?
59%. (Thus 41% comes out of the left ventricle).
What percentage of combined ventricular output flows through the fetal pulmonary artery?
11%
What is it about congestive heart failure that causes increased production and release of brain-natriuretic peptide?
Stretch of atrial and ventricular cardiac myocytes
What is a normal value of BNP?
0 - 99
What value of BNP is consistent with heart failure?
Any value in excess of 100.
What is the gold standard for diagnosis of heart failure?
Echocardiography (…BNP values are generally used to follow the progression of CHF and the responsiveness of CHF to interventions)
Describe NYHA functional classification Class 1.
No symptoms and no limitation in ordinary physical activity.
Describe NYHA functional classification Class 2.
Mild symptoms and slight limitation during ordinary activity. COMFORTABLE AT REST.
Describe NYHA functional classification Class 3.
Marked limitation in activity due to symptoms, even during less-than-ordinary activity. Comfortable ONLY at rest
Describe NYHA functional classification Class 4.
Severe limitations. Experiences symptoms even while at rest.
What is the appropriate endotracheal tube position in a patient with bronchopleural fistula?
The tube should be placed in the mainstem of the unaffected side (regardless of whether single or double lumen is used) with position confirmed via FOB.
What is the recommended position of the patient with an infected bronchopleural fistula?
Head-up position with the side of the fistula in the dependent position will help minimize cross-contamination.
What nerve provides sensation to the plantar aspect of the foot?
posterior tibial nerve
What are the branches of the posterior tibial nerve and where does it divide?
The posterior tibial nerve divides as it passes through the flexor retinaculum.
It becomes the medial and lateral plantar nerves.
What is entrapment of the posterior tibial nerve called?
Tarsal tunnel syndrome (neuropathic pain in the feet analogous to carpal tunnel syndrome in the hands)
What nerve provides innervation to the web space between the 1st and 2nd toes?
Deep peroneal nerve
What innervates the dorsum of the foot?
The superficial peroneal nerve.
What nerve innervates the lateral foot?
The sural nerve.
List the Mapleson systems in greatest to least efficiency for prevention of rebreathing during spontaneous ventilation.
A > D = F > C > B
List the Mapleson systems in greatest to least efficiency for prevention of rebreathing during controlled ventilation.
D = F > B > C > A
Name this circuit.
Mapleson A
Name this circuit.
Mapleson C
Name this circuit.
Mapleson D
Name this circuit.
Mapleson F (Jackson Rees)
What is the minimum fasting period for breast milk? For formula?
Breast milk = 4 hours
Formula = 6 hours
During what perioperative period are adults and children most likely to aspirate?
Adults = emergence/extubation
Children = induction
Note: this is just a matter of likelihood, as anyone can aspirate anywhere, anytime. I aspirated a Chipotle burrito in California once. It was very tasty. My lungs said “gracias”.
Under what age are children at greater risk of aspiration?
Less than 3 years of age.
Is bradycardia or tachycardia a predictive indicator of a SEVERE allergic reaction?
Bradycardia
Why is immediate IV fluid adminstration vital for treatment of anaphylaxis?
Because increased vascular permeablity can lead to transfer of 50% (fifty!) of intravascular volume into the interstitium.
During anaphylaxis, what drug should be used in the event that epinephrine fails to achieve hemodynamic instability?
Vasopressin should be used in this condition which is called Anaphylactic Shock Refractory to Catecholamines.
A decelerating flow pattern is characteristic of what types of ventilation?
pressure support and pressure control
What type of ventilation is associated with these waveforms?
Assist control (volume targeted)
What type of ventilation is associated with these waveforms?
Controlled mandatory ventilation
What type of ventilation is associated with these waveforms?
Pressure controlled ventilation
What type of ventilation is associated with these waveforms?
Pressure support ventilation
What is the formula for left ventricular stroke work index?
LVSWI = (MAP – PAOP) x SVI x 0.0136 g • m • m–2
where
LVSWI = left ventricular stroke work index
SVI = stroke volume index
What is the formula for right ventricular stroke work index?
RVSWI = (MPAP – CVP) x SVI x 0.0136 g • m • m–2
Blockade of what nerve roots is required to prevent pain from traction on the uterosacral ligaments or bladder during c-section?
L5 - S4
What is the uppermost spinal level of entry of intraabdominal visceral pain afferents?
T2
Pain sensations from the pelvic organs enter the spinal cord at what levels?
T10 - L1 (although some pelvic nerves accompany sympathetic fibers to go as high as T4 – hence the higher level of neuraxial block needed for c-section)
What class(es) of neuromuscular blockers can cause histamine release?
Benzylisoquinoliniums, and succinylcholine.
What neuromuscular blockers block cardiac muscarinic receptors?
Pancuronium > Rocuronium. (Vecuronium does not)
What neuromuscular blocker blocks autonomic ganglia?
d-Tubocurarine
Name five physiologic effects of histamine.
- Positive chronotropy (via H2 receptors)
- positive or negative inotropy depending circumstances
- coronary artery effects:
- H1 = vasoconstriction
- H2 = vasodilation
- peripheral vasodilation
- bronchospasm
What type of histamine receptor causes vasoconstriction of the coronary arteries?
H1
What type of histamine receptor causes vasodilation of the coronary arteries?
H2
What type of histamine receptor causes positive chronotropy?
H2
How does epidural analgesia affect maternal core temperature?
It increases it gradually over several hours! (typically less than 1°C total, but is also associated with a higher incidence of maternal fever during labor)
What is echothiophate?
It is an acetylcholinesterase inhibitor (organophosphate) that can be used as an eyedrop to lower IOP.
What is isoflurophate?
It is an acetylcholinesterase inhibitor (organophosphate) that can be used as an eyedrop to lower IOP.
What is xalatan?
It is a prostaglandin used as an eyedrop to lower IOP by increasing uveoscleral outflow of aqueous humor.
Patients receiving topical betablockers are at risk of developing what hemodynamic complication?
Exaggerated hypotension
What is the “mainstay” of hypercalcemia treatment?
Normal saline infusion.
Name the cardiovascular complications of lupus.
Pericarditis
Hypertension
CAD
Myocarditis
AS, MS, AR, MR
What are the pulmonary complications of lupus?
Pleural effusions
pHTN (2/2 recurrent pulmonary emboli)
Interstitial lung dz (rarely severe)
What are the renal complications of SLE?
Hematuria, proteinuria
nephrotic syndrome
rapidly progressive glomerulonephritis (rare)
What are the CNS consequences of SLE?
cerebral vasculitis
cognitive dysfxn
seizures
affective disorders
carotid artery dz
stroke
What are the hematologic consequences of SLE?
anemia
leukopenia
thrombocytopenia
antiphospholipid antibodies
recurrent pulmonary emboli
thromboses
Why might a pulse oximeter not work on a person with SLE?
Poor blood flow in the digits 2/2 vasospasm
What type of heat transfer is the most important cause of heat loss in the perioperative setting?
Radiation (which is why skin surface warming is the most effective way to decrease radiant heat loss)
A healthy subject has indwelling arterial catheters simultaneously transducing pressure from the brachial, radial, femoral, and dorsalis pedis arteries. Which catheter is likely to record the HIGHEST systolic pressure?
Dorsalis pedis
(because there are more branch points in the vasculature on the way there than at the other locations resulting in greater signal amplification)
What is another name for 15-methylprostaglandin F2alpha?
Hemabate
List the regional block locations according to their associated plasma local anesthetic concentrations from greatest concentration to least concentration.
Greatest concentration
Intercostal
Caudal
Lumbar epidural
Brachial plexus
Peripheral nerve
SubQ
Least Concentration
EMLA cream is a combination of what local anesthetics at what concentration?
Lidocaine and prilocaine, each at 2.5%
What does eutectic mean?
It refers to a mixture of substances whose melting point is lower than that of either of constituents alone. EMLA cream is an example of a eutectic mixture.
What is the metabolite of prilocaine responsible for methemoglobinemia?
O-toluidine
What age group is particularly susceptible to methemoglobinemia?
Infants < 3 -4 months of age
because their nicotinamide adenin dinucleotide methemoglobin reductase levels are only 50% of adult values at birth and do not reach adult levels until 3 - 4 months of age.
What type of receptors does dobutamine affect?
beta1 and, to a lesser extent, beta2 agonism
What effect does dobutamine have on afterload?
It reduces SVR thus decreases afterload.
Does dobutamine increase or decrease systemic blood pressure?
Unpredictable. Since dobutamine increases contractility and CO but also decreases SVR, it depends on how things play out between these two sides.
What receptors does norepinephrine affect?
alpha and beta1 (agonism)
What are the side effects of supraclavicular block?
Phrenic nerve block
Horner’s
pneumothorax (0.5% -5% with risk being experience-dependent)
What is the site of needle insertion for supraclavicular block without ultrasound guidance?
1cm superior to midpoint of clavicle which places it lateral to the clavicular head of the sternocleidomastoid.
What is normal P50 of oxygen-hemoglobin in adults?
26.7mmHg
Will hypothermia cause a left or right shift of the oxygen-hemoglobin dissociation curve?
left shift
Will alkalosis cause a left or right shift of the oxygen-hemoglobin dissociation curve?
left shift
Will decreased 2,3-DPG cause a left or right shift of the oxygen-hemoglobin dissociation curve?
left shift
Will fetal hemoglobin cause a left or right shift of the oxygen-hemoglobin dissociation curve?
left shift
Will carboxyhemoglobin cause a left or right shift of the oxygen-hemoglobin dissociation curve?
left shift
Will methemoglobin cause a left or right shift of the oxygen-hemoglobin dissociation curve?
left shift
Will hyperthermia cause a left or right shift of the oxygen-hemoglobin dissociation curve?
right shift
Will acidosis cause a left or right shift of the oxygen-hemoglobin dissociation curve?
right shift
Will increased 2,3-DPG cause a left or right shift of the oxygen-hemoglobin dissociation curve?
right shift
Will increased CO2 cause a left or right shift of the oxygen-hemoglobin dissociation curve?
right shift
Will pregnancy cause a left or right shift of the oxygen-hemoglobin dissociation curve?
right shift
What are some causes of hypovolemic hyponatremia?
Diarrhea
Diuretics
Cerebral salt wasting
What are some causes of normovolemic hyponatremia?
SIADH
Adrenal insufficiency
Hypothyroidism
What are some causes of hypervolemic hyponatremia?
cirrhosis
heart failure
nephrotic syndrome
If a patient is hyponatremic but has normal serum osmolality (280 - 300 mOsm), what is the differential?
Hyperlipidemia
Hyperproteniemia
If a patient is hyponatremic but has high serum osmolality (>300 mOsm), what is the differential?
Hyperglycemia
Hypertonic sodium-free solutions
If a patient is hyponatremic but has low serum osmolality (280 - 300 mOsm) and low urine sodium (<20mmol/L), what is the diagnosis?
water intoxication
If a patient is hyponatremic but has low serum osmolality (280 - 300 mOsm) and high urine sodium (>20 mmol/L), what is the differential?
If the patient is hypovolemic:
- cerebral salt wasting
- diarrhea
- diuretics
If the patient is normovolemic:
- SIADH
- Adrenal insufficiency
- Hypothyroidism
If the patient is hypervolemic:
- cirrhosis
- heart failure
- nephrotic syndrome
Describe the effect of obstructive shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Obstructive shock
HR increased
MAP decreased
CVP increased
PAOP increased
SVR increased
Describe the effect of hypovolemic shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Hypovolemic shock
HR increased
MAP decreased
CVP decreased
PAOP decreased
SVR increased
Describe the effect of isolated RV failure cardiogenic shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Isolated RV failure cardiogenic shock
HR increased
MAP either increased or decreased
CVP increased
PAOP normal
SVR increased
Describe the effect of isolated LV failure cardiogenic shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Isolated LV failure cardiogenic shock
HR increased
MAP either increased or decreased
CVP normal
PAOP increased
SVR increased
Describe the effect of biventricular failure cardiogenic shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Biventricular failure cardiogenic shock
HR increased
MAP increased or decreased
CVP increased
PAOP increased
SVR increased
Describe the effect of early distributive shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Early distributive shock
HR increased
MAP decreased
CVP decreased or normal
PAOP decreased or normal
SVR decreased
Describe the effect of late distributive shock on HR, MAP, CVP, PAOP, and SVR (in terms of increase, decrease, or remains normal).
Late distributive shock
HR increased
MAP decreased
CVP increased or normal
PAOP increased or normal
SVR decreased
Describe how spinal shock may differ hemodynamically from all other forms of shock.
All forms of shock seem to be associated with tachycardia. In spinal shock, the HR could be decreased from normal.
Equalization of diastolic pressures and filling pressures is consistent with what pathological event?
Cardiac tamponade
In severe preeclampsia, what is the goal reduction of BP in terms of percentage?
No more than 15 - 20% reduction.
What is first line therapy for treatment of blood pressure in preeclampsia?
Labetalol and hydralazine
What nerve innervates the palmar aspect of the thumb?
Median nerve
What innervates the fifth digit and the intrinsic muscles of the hand?
ulnar nerve
Where is the ulnar nerve usually in relation to the axillary artery?
inferior (ulnar is under)
Where does the median nerve tend to lie in relation to the ulnar nerve in the axilla?
superior and superficial to the ulnar nerve
What nerve is subject to injury in a midhumeral fracture?
radial nerve
What innervates the dorsal webspace between the thumb and forefinger?
The radial nerve
The musculocutaneous nerve provides motor innervation to what muscles?
biceps brachii
coracobrachialis
brachialis
What nerve provides sensation to the lateral forearm?
musculocutaneous nerve
What provides sensory innervation to the medial hand and fifth digit?
ulnar nerve
What nerve provides sensory innervation to most of the palmar hand?
Median nerve (with the exception of the medial aspect of the hand which is provided by the ulnar nerve)
Which fingertips are innervated by the radial nerve?
None! The finger tips both dorsal and palmar are innervated by the median nerve (thumb - lateral half of ring finger) and the ulnar nerve (medial half of ring finger - pinky).
The radial nerve does innervate part of the dorsum of the proximal thumb and the dorsum proximal fingers.
What nerve provides somatic innervation to the perineum and pelvic floor?
pudendal nerve
What nerve innervates the distal two thirds of the vagina?
pudendal nerve
what nerve provides somatic innervation of the anus?
pudendal nerve
Neurolytic blockade of what nerve will affect control of urinary and anal sphincters?
pudendal nerve
What is the anatomical range of the visceral afferents contained by the celiac plexus?
From the distal esophagus to the splenic flexure of the colon. But NOT the body wall in the peritoneum.
What visceral afferents pass through the superior hypogastric plexus?
uterus, bladder, rectum (but NOT anal skin, perineum, or pelvic floor muscles–those go through the pudendal nerves).
What visceral afferents do the lumbar sympathetic ganglia contain?
They don’t. They contain efferent sympathetic fibers to the lower extremities.
What pressure in cm H20 is associated with compromised capillary blood flow in the tracheal mucosa?
> 30 cm H20
What is the single most important patient attribute affecting the risk of developing PDPH?
Patient age. Younger > older. Highest risk in late teens or early twenties.