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Cardiac Anesthesiology Made Ridiculously Simple - page 4 / 13





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MR: Preload:Keep it up Afterload: Down SVR: Down HR: 50-80 Rhythm: NSR

Prebypass Hemodynamics: You should try to keep the blood pressure within ± 20% of baseline ward pressure. Heart rates between 40 and 80 are generally fine depending on the clinical situation prior to bypass.

Bypass Hemodynamics: You should keep the MAP between 40-80 during the cold period of bypass (cross clamp on) and between 60-80 during warm bypass (cross clamp off). There will be exceptions such as patients with carotid vascular disease or chronic renal insufficientcy that may need higher pressures (60-80 mmHg) for the entire pump run.

Post Bypass Hemodynamics: Systolic blood pressure greater than 80 mmHg is fine. If it is between 100 and 120 mmHg everyone will be happy. If it is greater than 120 mmHg the patient is hypertensive and there will be more bleeding. Cardiac index greater than 2.0 is fine. Pa Diastolic less than 20 mmHg, CVP less than 15 mmHg. If CVP is ever greater than PAD there is a problem: poor calibration or right ventricular failure. Always consider surgical manipulation of the heart if the chest is open, or tamponade when it is closed, for hypotension.

Preinduction Hemodynamic Measurements: If you put a PA catheter in prior to induction you have indicated that you need it for patient management. You should therefore measure and record SAP, HR, CVP, PAP, PAO, and CO prior to anesthetic induction. If there is a problem you should correct it prior to induction. You can preoxygenate the patient during this time and free up one hand by using the mask strap to hold the mask in place.

Fluids: There are lots of theories on fluids and little data to support the strongly held beliefs. Cardiac cases can easily suck up large amounts of fluid intraoperatively with little obvious benefit. All of that fluid then has to be diuresed postoperatively frequently by administering large amounts of lasix with subsequent electrolyte disturbances. Post operative extubation is frequently delayed by intraoperative fluid administration. Please attempt to limit fluid administration intraoperatively. A few suggestions. If you have two large bore IV's hep lock one of them. Try to give less than 500 cc of LR prior to bypass. Do not administer any fluids during bypass except for fluid required for vasoactive drugs. Use hespan post bypass up to 20 cc/kg, then shift to albumin. If you use hextend, the 20 cc/kg limit may or may not apply. Use a mechanical metering device on any carrier lines to prevent accidental high flows. Use neosynephrine to support pressure before giving large amounts of fluid prebypass.

Fluid Tally's: Tally the estimated blood lost, and fluids administered including crystalloid, colloid, Blood, cell saver, pump blood, bypass prime volume, and total fluid given by perfusionist on your record. This is a change from previous efforts where we ignored everything but the crystalloid, colloid, given by anesthesia, and the blood given by anesthesia and perfusionists. The perfusionists can give large amounts of crystalloid and we need to note it on the anesthesia record. if they give hespan or hextend in the pump prime we should know about it.

Ischemia: Patients have CABG surgery because of myocardial ischemia. 40% of patients undergoing CABG surgery have intraoperative episodes of myocardial ischemia. You should record a 5 lead ECG prior to induction for a baseline comparison. Ask the patient if they are having chest pain at this time. You should look at the ECG either continuously or at least every 60 seconds and ask - What is the rhythm? Is there ischemia? Only by absolute attention to the ECG will you detect a substantial fraction of the ischemia.

When the blood flow to myocardium is insufficient, it immediately stops contracting. This process takes 5 to 10 seconds. At 60 to 90 seconds the ECG ST-T wave starts to change. This focal reduction in cardiac function can be detected by watching the ECHO image. The best level is a short axis mid papillary view. You should record a fixed pre incision short axis mid papillary view for comparison. The ECHO is an adjunct to care not a requirement. Do not ignore the patient when looking at the echo.

Induction and Intubation: Never induce the patient without a surgeon who can put the patient on bypass in the room. Never induce without a perfusionist and a pump. They should be able to place the patient on bypass in less than 5 minutes if the patient arrests on induction. They can't do that, if they aren't there and you will be liable. Take care to avoid hypotension and hypoxia (really? Yes!). Try to limit the LR for the case to less than a liter. That means less than 500 cc prior to bypass. Use 500 cc bags to avoid run away infusions. Most people you put to sleep drop their blood pressure. In cardiac cases we attempt to limit the drop by giving vasoactive substances. There are two approaches to giving these drugs. You can induce the patient and then respond to the hypotension in the 95% of patients that you induce. The alternative is to start a neo infusion in all patients prior to induction and then turn it off when not needed. The second approach is vastly smoother and easier on everyone because you don’t have to scramble around getting something going.

TEE: We are not supposed to use Cidex any more to clean the probes. Therefore you will be issued something that looks like Dr. Ruth Westheimer was consulting at Marine World. Please try to maintain professional demeanor when performing this procedure. Roll the latex prophylatic over the plactic filler device. Then fill the reservoir tip with ultrasonic jelly. There are two

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