Anesthesia Student Survival Guide.pdf - Index of

PhysiOlOGy And AnesthesiA fOr CArdiAC And thOrACiC surGery ● 273
preoperative ECG with a rhythm strip to assess for rhythm abnormalities and
a chest X ray to assess for signs of heart failure (pulmonary edema) or other
co-existing pulmonary disease. An echocardiogram will give a determination
of a patient’s left and right ventricular function as well as provide information
about any valvular abnormalities. Finally, many patients who present for cardiac
surgery will have either a stress test or cardiac catheterization performed – both
of which will provide an understanding of areas of the myocardium which are
at risk for ischemia during the perioperative period.
Monitoring
Monitoring should include a pre-induction arterial line and at least one large
bore (16–18 gauge or greater) IV line. A CVP line, and sometimes a PA catheter
will be placed before or after induction depending on IV access and severity
of the patient’s disease (See Chap. 11 on Patient Monitoring). After induction,
a transesophageal echocardiography (TEE) probe is placed to evaluate heart
anatomy and function. In addition to standard ASA monitors, the patient’s
temperature and urine output are also monitored.
Induction and Maintenance
Induction is typically performed with a high dose opiate induction (fentanyl
5–50 mcg/kg) and either etomidate, propofol, or thiopental, depending on the
patient’s underlying disease state. Sevoflurane and isoflurane are acceptable, provided
that hemodynamics are well controlled. Pancuronium, cisatracurium, and
vecuronium are good choices for paralytics, although pancuronium may cause
tachycardia which is undesirable in coronary artery disease. Succinylcholine can be
used carefully when indicated with a precurarizing dose of non-depolarizing neuromuscular
junction blocker. Avoid using ketamine, which can increase the risk of
myocardial ischemia, and can cause cardiac dysfunction in patients who are already
catecholamine-depleted. During CPB procedures, nitrous oxide is avoided
because of its ability to expand the size of gas emboli that can arise in the pump.
Pre-Bypass Considerations
During sternotomy, deflate the lungs to prevent injury during chest opening
using the electric saw. Reoperation patients require a great degree of preparation
and large bore IV placement, since the heart and large vessels can be
adhesed to the chest wall anteriorly and ruptured upon chest entry. Consider
an antifibrinolytic agent such as epsilon-aminocaproic acid or tranexamic acid