Anesthesia Student Survival Guide.pdf - Index of

PhysiOlOGy And AnesthesiA fOr CArdiAC And thOrACiC surGery ● 275
Cardiopulmonary Bypass Circuit
Coronary Sucon Arterial
Reservoir
Auxiliary
filter
RA Cannula
LV Vent
Paent
Return
Arterial line
(via femoral
artery or aorta)
filter
Oxygenator
Venous return
(via RA or SVC and IVC)
Heat
exchanger
Figure 17.3 Cardiopulmonary bypass circuit. (Image courtesy J. Ehrenfeld).
Roller pump
small IV bolus. Isoflurane can be given to the patient via the perfusion pump.
Hyperglycemia can result in adverse outcomes in cardiac surgery and should
be treated appropriately with insulin as indicated.
Potential surgical or perfusion catastrophies during cardiopulmonary bypass
include aortic dissection, inadvertent carotid or innominate artery cannulation,
reversed cannulation, obstruction to venous return, and massive air embolism.
Other medical disasters include drug administration errors such as protamine
administration while still on bypass. Postoperative complications after CPB
include pulmonary edema (“pump lung”/ARDS), stroke, global cerebral
ischemia, fluid/electrolyte imbalances, coagulopathy, and renal dysfunction.
Weaning From Cardiopulmonary Bypass
The patient’s blood is rewarmed by the heat exchanger in the CPB circuit.
A core body temperature of at least 36°C is optimal. Many providers administer
benzodiazepines because recall is most common during this period of rewarming.
Potassium, glucose, and hematocrit levels are all checked and corrected
before weaning. The heart may temporarily require inotropes or pacing in
order to wean from CPB. Positive pressure ventilation is often used to evacuate
air from the heart, great vessels, and grafts. Hypotension upon weaning from
CPB can be the result of hypovolemia, myocardial dysfunction, valve abnormalities,
vasodilation, and pulmonary hypertension. Respiratory abnormalities
(“pump lung”) can also prevent a successful wean from bypass and should be
treated with aggressive respiratory therapy.