Immediate Postop Management (#4)

Question 1

Effect of acidosis on the heart?

Answer 1

• decreased cardiac output
• decreased contractility
• decreased vascular response to catecholemines
• lowered threshold for VF, more sensitive to dysrhythmias

Question 2

Respiratory effects of acidosis?

Answer 2

impaired respiratory muscle function, dyspnea, tachypnea

Question 3

Respiratory acidosis will cause (increase/decrease) in PA pressures.

Answer 3

Respiratory acidosis will cause an increase in PA pressures.

Question 4

common causes of respiratory acidosis after cardiac surgery

Answer 4

1) oversedation
2) NMB
3) shivering
4) neurologic issues

Question 5

A PE will cause respiratory (acidosis/alkalosis)? Why?

Answer 5

Severe hypoxemia causes hyperventilation as a compensatory mechanism…ABG will show respiratory ALKALOSIS. (lowered CO2.)

Question 6

LR is metabolized into what compound?

Answer 6

Bicarbonate (HCO3)

…so it should not be used in pts who are alkalotic.

Question 7

Risk of giving more than 1-2 L of fluid to postop pt?

Answer 7

Increased risk of pulmonary edema, hemodilution, diluted clotting factors, increased bleeding risk

Question 8

Hyperkalemia manifestations on EKG?

Answer 8

Peaked T wave
ST depression
Prolonged PR
Wide QRS

Question 9

Hyperkalemia has what effect on cardiac pacemakers?

Answer 9

Can cause loss of capture (increases the sensitivity threshold)

Question 10

CaCl versus Calcium gluconate

Answer 10

CaCl has 3x as much calcium concentration as calcium gluconate, and causes increase in BP/CO when given rapidly.

Question 11

How does blood transfusion cause metabolic alkalosis?

Answer 11

Citrate in banked blood is a bicarbonate precursor. When broken down, it can cause metabolic alkalosis.
(in a patient with liver dysfuction it may cause metabolic acidoseis, because they are unable to metabolize the citratrate

Question 12

Pacemaker output

Answer 12

amount of stimulation used to capture the heart

Question 13

Pacemaker capture

Answer 13

muscle depolarization following an electrical stimulus

Question 14

stimulation threshold

Answer 14

minimum output needed to consistantly capture the heart

Question 15

sensitivity

Answer 15

degree that the pacemaker senses signals

Question 16

why do pacemaker wires fail 4-5 days after surgery?

Answer 16

inflammation around the wire/myocardial interface causes increased thresholds

Question 17

a LOW sensitivity means the pacer will see more or less of the patient’s intrinsic rhythm?

Answer 17

More (imagine the bar is low to the EKG waveform)

Question 18

What is atrial tracking?

Answer 18

each pacemaker atrial event triggers a ventricular event (use only in SR, not afib/aflutter)

Question 19

What is the av interval?

Answer 19

length of time between atrial sensing/pacing and ventricular pacing (default 170 ms)

Question 20

which type of heart surgery are pts most likely to need a pacer?

Answer 20

aortic valve replacement - due to the proximity of the aortic suture line to the conduction pathway

Question 21

Why are atrial EKGs useful?

Answer 21

Helps identify atrial dysrhythmias of unknown origin

Question 22

Is bubbling in the chest tube a normal finding?

Answer 22

No - indicated pulmonary or system air leak

Question 23

The highest incidence of VTE occurs when? And in which leg?

Answer 23

POD 4-6, in the non-harvested leg