Book 6, Case 6-Fem pop bypass, smoking, CAD, DM

Question 1

What is the ankle-brachial index?

Answer 1

a noninvasive Doppler measurement of the
ankle and brachial systolic pressures, utilized to assess the presence and severity of
peripheral artery disease.
normal ABI would range between 1. 0 and 1.1, a ratio less
than 0.9 is associated with claudication secondary to peripheral arterial disease
Moreover, a value less than 0.4 (some sources say 0.5) is
associated with rest pain, while an index less than 0.2 (some sources say 0.25) is associated
with ulceration and the development of a gangrenous extremity.

Question 2

Pre-operataive blood pressure in this fem pop bypass pt (elective) is 185/105-wyd?
Why is this bad? what will you do if the case can NOT be delayed?

Answer 2

given the increased perioperative
risk for blood pressure lability, myocardial ischemia, dysrhythmias, congestive heart failure,
and stroke associated with stage 3 hypertension (2: 180/110 mmHg), I would prefer to delay
this surgery for at least 6-8 weeks to optimize his blood pressure and allow for the
normalization of his intra vascular volume and cerebral autoregulation curve. However, if a
delay were unacceptable due to the significant risk oflimb loss, I would: (1) perform a
focused history and physical (2) obtain an ECG, electrolyte panel, blood urea
nitrogen, and creatinine to further evaluate end-organ damage and identify metabolic
derangements resulting from hypertensive medications; and (3) carefully reduce the patient’s
blood pressure with a short acting agent, like esmolol, or a renal protective agent, like
fenoldopam (a selective D 1 receptor agonist that preserves or augments renal blood flow
while reducing blood pressure), to less than 160/110 mmHg, while monitoring him carefully
for signs of end-organ hypoperfusion.

Question 3

Hypertensive urgency:

Answer 3

180/120 in absence of progessive target oragn dyfunction-often asymptomatic

emergency: organ dysfunction

Question 4

Causes of HTN (medical things-not intraop)

Answer 4

CKD, Chronic steroid therapy (Cushing’s), pheo, amphetamines

Question 5

What are signs of end organ damage?

Answer 5

left ventricular hypertrophy, (2) angina, (3)
myocardial infarction, (4) congestive heart failure, (5) coronary artery disease, (6) stroke,
(7) transient ischemic attack, (8) chronic kidney disease, (9) retinopathy, and (10)
peripheral artery disease.

Question 6

What is the significance of this patient’s left BBB? And what does LBBB look like on EKG

Answer 6

it
carries a much more significant association with ischernic heart disease, aortic valve disease,
left ventricular hypertrophy, congestive heart failure, and hypertension than does right bundle
branch block (RBBB); (2) the diagnoses of myocardial infarction by ECG is very difficult
because the bundle branch block pattern hides the ST-segment and T-wave findings
associated with cardiac ischernia; (3) the widened QRS complexes lend to mistaking
supra ventricular tachycardia for ventricular tachycardia; and ( 4) the placement of a
pulmonary artery catheter can lead to third-degree heart block (secondary to the occurrence
of transient RBBB during placement).

QRS duration must be >120 msec
QS or RS in lead V1
R, R’ in left chest leads V5 or V6

Question 7

Pt had severe claudication, LBBB and bad HTN-what kind of stress testing is most appropriate?

Answer 7

I think that pharmacologic stress myocardial perfusion scintigraphy
using adenosine or dipyridamole would be most appropriate. First, his severe claudication
would limit his ability to adequately cooperate with exercise stress testing.
Finally, while both
dobutamine stress echocardiography and pharmacologic stress myocardial perfusion
scintigraphy are recommended for patients with left bundle branch block, dobutamine should
be avoided in patients with severe hypertension

Question 8

Remember to avoid adenosine in which patients?

Answer 8

critical carotid disease or significant risk for bronchospasm.

Question 9

Delays for balloon angio?

Answer 9

Following balloon angioplasty, all non-emergent surgery should be delayed
for at least 2-4 weeks to allow sufficient time for the vessels injured during the procedure to
completely heal.

Question 10

Creatinine clearance less than ___ is risk factor for cardiac complications

Answer 10

less than 60

Question 11

Why are epidurals good as far as anesthesia?

Answer 11

attenuation of the
postoperative hypercoagulable state often associated with general anesthesia), reduce the
number of postoperative respiratory and infectious complications (due to improved pain
control and respiratory function), and decrease the incidence of myocardial
ischemia/infarction

Question 12

If a pt has received heparin for more than 4 days, what do you need to check before placing an epidural?

Answer 12

PLATELETS

Question 13

You decide to place an epidural catheter, but note bleeding through the epidural needle
after entering the epidural space. Do you need to delay surgery? (Vascular surgery)

Answer 13

recognizing that heparinization for vascular surgery usually
involves an intravenous injection of only 5,000 - 10,000 U of heparin, I would make the
surgeon aware of the increased risk of epidural or spinal hematoma associated with systemic
heparinization
However, if this patient were undergoing complete heparinization, as occurs during coronary
artery bypass surgery, I would recommend delaying the procedure for 24 hours to avoid
exposing the patient to an unacceptably high risk of developing an epidural or spinal
hematoma.

Question 14

Who is continuous ST segment analysis NOT helpful for?

Answer 14

its use is limited in those with certain
underlying electrocardiographic abnormalities.

Other baseline electrocardiographic abnormalities that would hinder

accurate computerized ST-segment analysis include Wolff-Parkinson-White syndrome, acute
pericarditis, left ventricular hypertrophy with strain, digitalis effect, and hypokalemia

Question 15

Pt has LBBB and surgeon wants you to place a PAC for post op mgmt-wyd?

Answer 15

I’d say no due to the risk of complete heart block, however if surgeon was insistent-I would alert them of risks and make sure transcutaneous pacing was available

Question 16

Absolute contraindications to PAC?

Answer 16

Right sided endocarditis, tumors, or masses

Question 17

Hypotension after induction:

Answer 17

hypotension from induction
CV
lability assoc with hypotension
perioperative continuation of beta blocker
tension ptx if you placed a central line
allergic reaction

Question 18

Risk factors for contrast induced nephropathy?

What do you do to decrease this risk?

Answer 18

renal insufficiency, diabetes mellitus, hypertension, and likely hypovolemia secondary to
poorly controlled chronic hypertension (other risk factors for contrast-induced nephropathy
include age, anemia, hypoalbuminemia, multiple myeloma, congestive heart failure, renal
transplant

Prevention:

• Hydration: 1 mL/kg 4 hours before surgery and 12 hours after dye
• Ask surgeon to use low viscosity agent
• sodium bicarb to alkalinize urine
• Ascorbic acid (anti-oxidant)

Question 19

What does fenoldopam do and will you give it for renal protection if you are giving contrast?

Answer 19

dopaminergic-1 agonist-may reduce post op renal failure, but evidence is conflicting.
Systemic vasodilation in dose dependent manner while preserving renal blood flow. Good for treating severe blood pressures in patients with renal insufficiency

Question 20

Protamine reactions:

Answer 20

-Type 1: Histamine release resulting in hypotension
Type 2 anaphylactic: type 2b anaphylactoid
type 3: severe pulm HTN leading to R. heart failure

Question 21

What are you going to do about protamine reactions?

Answer 21

Avoid any additional protamine
administration and check the patient’s pulmonary artery pressure. If his pulmonary artery
pressure were low or normal, this would be consistent with a pharmacologic reaction
(histamine-induced hypotension secondary to rapid administration), anaphylaxis, or an
anaphylactoid reaction, and I would begin with the administration of fluids and
vasoconstrictors. If the patient did not respond adequately or developed signs consistent with
an anaphylactic or anaphylactoid reaction (i.e. urticarial, facial edema, bronchospasm,
pulmonary edema, etc.), I would administer epinephrine, an inhaled -agonist,
corticosteroids, and an antihistamine.
if his pulmonary artery pressures were high
and/or there were signs of right heart failure, I would administer epinephrine and/or an
inotrope with vasodilating properties (i.e. milrinone, amrinone, or isoproterenol); and
consider providing nitric oxide, if necessary. If the patient was hemodynamically stable, but
did not respond adequately following the administration of inotropes, I would try
administering a low dose of heparin (70U/kg), with the hopes that this would break up large
heparin-protamine complexes

Still no bueno? I would talk to the
surgeon about full heparinization and the institution of cardiopulmonary bypass.

Question 22

Concerns for pts s/p fem pop bypass?

Answer 22

renal failure
graft occlusion
arrhythmias
MI-cardiac morbidity and mortality is highest in post op period

Question 23

If they ask what can be done to minimize post op complications, right answers are always:

Answer 23

employing full monitoring, to identify any hemodynamic changes,ensuring tight control of his heart rate and blood pressure;
Avoid anemia
CONTINUE BETA BLOCKER POST OP

Question 24

AGAIN, risk factors for acute renal failure:

Answer 24

preexisting renal disease,
peripheral vascular disease, recent exposure to radiocontrast dye, hypertension, diabetes,
vascular surgery, advanced age, and the perioperative continuation of his aspirin and ACE
inhibitor

Question 25

So wyd when pt has minimal urine output after big vascular surgery? How long does this usually last?

Answer 25

My primary goal in treating his acute renal failure is to limit any additional
injury. Therefore, I would inspect his urinary catheter for obstruction and evaluate his blood
pressure, central venous pressure, pulmonary capillary wedge pressure, and cardiac output to
identify a pre-renal cause of his reduced urine output. If I believed this to be pre-renal
failure, I would correct any electrolyte or acid-base derangements and treat with fluids
(hypovolemia), vasopressors (hypotension), inotropes (congestive heart failure), and diuretics
(congestive heart failure), as indicated. If I believed this was intrinsic renal failure, possibly
secondary to intraoperative radiocontrast dye injection, I would consult a nephrologist,
provide supportive care, and consider dialysis, if necessary. Fortunately, this complication is
normally self-limited, resolving within 7-14 days.

Question 26

How is contrast induced nephropathy diagnosed/

Answer 26

Contrast-induced nephropathy is diagnosed when there is a 25% or 0.5 mg/dL
( 44 μmol/L) or greater increase in serum creatinine from baseline within 3 days of
radiocontrast media injection. It is also important to rule out other potential causes of renal
insufficiency.