Immediate Postop Management (#4) Flashcards
Effect of acidosis on the heart?
- decreased cardiac output
- decreased contractility
- decreased vascular response to catecholemines
- lowered threshold for VF, more sensitive to dysrhythmias
Respiratory effects of acidosis?
impaired respiratory muscle function, dyspnea, tachypnea
Respiratory acidosis will cause (increase/decrease) in PA pressures.
Respiratory acidosis will cause an increase in PA pressures.
common causes of respiratory acidosis after cardiac surgery
1) oversedation
2) NMB
3) shivering
4) neurologic issues
A PE will cause respiratory (acidosis/alkalosis)? Why?
Severe hypoxemia causes hyperventilation as a compensatory mechanism…ABG will show respiratory ALKALOSIS. (lowered CO2.)
LR is metabolized into what compound?
Bicarbonate (HCO3)
…so it should not be used in pts who are alkalotic.
Risk of giving more than 1-2 L of fluid to postop pt?
Increased risk of pulmonary edema, hemodilution, diluted clotting factors, increased bleeding risk
Hyperkalemia manifestations on EKG?
Peaked T wave
ST depression
Prolonged PR
Wide QRS
Hyperkalemia has what effect on cardiac pacemakers?
Can cause loss of capture (increases the sensitivity threshold)
CaCl versus Calcium gluconate
CaCl has 3x as much calcium concentration as calcium gluconate, and causes increase in BP/CO when given rapidly.
How does blood transfusion cause metabolic alkalosis?
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
Pacemaker output
amount of stimulation used to capture the heart
Pacemaker capture
muscle depolarization following an electrical stimulus
stimulation threshold
minimum output needed to consistantly capture the heart
sensitivity
degree that the pacemaker senses signals
why do pacemaker wires fail 4-5 days after surgery?
inflammation around the wire/myocardial interface causes increased thresholds
a LOW sensitivity means the pacer will see more or less of the patient’s intrinsic rhythm?
More (imagine the bar is low to the EKG waveform)
What is atrial tracking?
each pacemaker atrial event triggers a ventricular event (use only in SR, not afib/aflutter)
What is the av interval?
length of time between atrial sensing/pacing and ventricular pacing (default 170 ms)
which type of heart surgery are pts most likely to need a pacer?
aortic valve replacement - due to the proximity of the aortic suture line to the conduction pathway
Why are atrial EKGs useful?
Helps identify atrial dysrhythmias of unknown origin
Is bubbling in the chest tube a normal finding?
No - indicated pulmonary or system air leak
The highest incidence of VTE occurs when? And in which leg?
POD 4-6, in the non-harvested leg
