Physical Activity and the Path to Recovery after Cardiac Surgery
The most common surgical procedure encountered is the Aorto-Coronary Bypass Graft ACBG for various indications such as left main coronary artery stenosis, severe triple-vessel disease, angina refractory to medical therapy, or recurrent CHF due to ischemia. Less common are removal of intracardiac tumors and LV aneurysmectomy. To perform the surgery, the patient is usually put on "pump" or cardiopulmonary bypass CPB.
This involves cannulation of the right atrium and aorta and later cross-clamping of the aorta , allowing the entire cardiac output to bypass the patient's heart and lungs. Blood flow is maintained using a pump and the blood is oxygenated via a membrane oxygenator incorporated into the circuit.
Several myocardial preservation techniques are used to protect the heart from ischemic damage during this period. Cardioplegic arrest is induced using a hyperkalemic solution to induce asystole and thus decrease myocardial metabolism and oxygen consumption. The heart is usually cooled. While "on pump", the patient's BP and cardiac output are controlled by by the perfusionist and also the anesthesiologist by means of vasoactive medications and inotropes.
Post cardiac surgery care pdf editor
Long pump times are associated with increased post-operative complications such as bleeding, myocardial stunning, and multi-system organ failure. It is sometimes difficult to liberate the patient from CPB or "get him off pump.
Pressors or inotropes are often used in order to aid "coming off pump. Most often, these dysrhythmias are transient and resolve. In the past few years, more cases are being done with "beating heart" or "off pump". In some operations involving the aortic root, cross-clamping and cannulation of the aorta are not feasible.
The patient is systemically cooled as much as possible usually below 28 C and a large dose of barbiturates are given as a neuroprotective agent. The circulation is then completely arrested for a brief period of time to allow completion of the surgical anastomosis.
The resident should be present in the ICU when the patient arrives from the operating room to receive a sign-over from the anesthesiologist and the cardiac surgical team. During this period, the ICU nurses will be transferring the patient to the ICU monitors and checking all lines and infusions.
The nurse will then do the initial set of hemodynamic readings. The Respiratory Technician will place the patient on a ventilator. Unless the patient is unstable it is best to stay out of the way of the nurses during this period, and wait until they are finished with their assessment before examining the patient. Patients are usually warmed to at least 34 C before transfer to the ICU. Patients are rewarmed using the "Bear Hugger".
This blows warm air over the body surface to warm by convection. The ICU Fellow or Attending should be notified about any significant bleeding whether it is believed to be "medical" or "surgical. Practically speaking, one does not always have the luxury of time with patients bleeding significantly and one may have to resort to empiric or "shotgun" therapy. The principle objective when giving PRBC's is the improvement of inadequate oxygen delivery and the minimization of adverse outcomes as a result of this.
In a patient who is actively bleeding and thus who's hemoglobin mass is not in a steady state, one must be more liberal in transfusing PRBC's to avoid severe impairments in peripheral oxygen delivery. However, with a patient who is not bleeding rapidly, one can take a more deliberate approach to transfusion.
Remember that there are several potential risks associated with the transfusion of red blood cells, including. The use of a single Hgb trigger for all patients, and other approaches that fail to consider all important physiologic and surgical factors affecting oxygenation are not recommended.
The risk of complications from inadequate O2 delivery should determine the need for transfusion. Signs of inadequate oxygen delivery include a low mixed venous oxygen saturation, high lactic acid level, or clinical signs of organ dysfunction that cannot be attributed to other causes. Most post-operative cardiac patients, who are hemodynamically stable, are not actively bleeding, and are following an otherwise uncomplicated post-operative course, tolerate a Hgb as low as 7.
After Heart Surgery
There are numerous causes for hypotension post-operatively. Proper management of the hypotensive patient in the ICU requires that the precise etiology for the hypotension is determined and therapy is directed towards reversal of this specific problem.
Equation 1 demonstrates that hypotension can be caused by a "pump problem" low cardiac output or a low SVR arterial "circuit" problem.
The following is an approach to managing the hypotensive patient;. The following is a very simplified approach to the choice of inotropes and vasopressors.
Cardiac tamponade is compression of the heart that impairs ventricular filling and leads to a low cardiac output. The presentation of tamponade can be variable and requires a high index of suspicion. No single bedside test or finding is sensitive or specific enough to absolutely rule in or out tamponade.
A "typical" presentation would be a patient who had a normal ejection fraction pre-operatively, underwent uncomplicated ACBG, initially had excellent hemodynamic parameters, bled from the mediastinal sumps moderately, then the bleeding "stopped" or blood ceased to drain from the sumps. Always check to make sure the sumps are not obstructed. This is followed by hemodynamic deterioration with tachycardia, declining cardiac output and stroke volume, and decreasing mixed venous oxygen.
The urine output typically decreases and other signs of end-organ hypoperfusion develop including CNS changes and acidosis. The IABP consists of a long cylindrical balloon placed at the end of a catheter placed in the descending thoracic aorta.
The tip of the catheter should be positioned just distal to the left subclavian artery. The balloon should also be placed so that it does not occlude the renal or mesenteric arteries. Helium is pumped into the balloon to inflate it at the beginning of diastole. The balloon is deflated at the end of diastole. It has been described as the "ideal inotrope". In the failing heart it can decrease myocardial workload while increasing coronary perfusion. IABP - A systematic review of the literature.
Enter your keywords. Section menu. Introduction to cardiac surgery Immediate post-op care History Physical exam and assessment Labs and tests Warming Bleeding Surgical bleeding Etiology of "medical" bleeding Treatment of "medical" bleeding Transfusion of packed RBC's Hemodynamic management Hypotension and low cardiac output Inotropes and vasopressors Tamponade Mechanical assist devices Intra-aortic balloon pump Introduction to cardiac surgery The most common surgical procedure encountered is the Aorto-Coronary Bypass Graft ACBG for various indications such as left main coronary artery stenosis, severe triple-vessel disease, angina refractory to medical therapy, or recurrent CHF due to ischemia.
Immediate post-op care The resident should be present in the ICU when the patient arrives from the operating room to receive a sign-over from the anesthesiologist and the cardiac surgical team. History Collect the following information from the anesthesiologist, surgeon, and the patient chart.
Difficulty coming off pump may imply problems with myocardial preservation or with the revascularization.
Introduction to cardiac surgery
Significant bleeding Other significant co morbidity, with emphasis on those conditions that may alter the post-operative management or course carotid artery disease, COPD, asthma, diabetes, renal failure, hepatic failure, etc. Remember that tube displacement or pneumothoraces can occur or become apparent at any moment.
Verify that the patient's oxygen saturation is adequate. Check the ABG results as soon as they are available.
Verify correct ventilator settings. Check the patient's heart rhythm.
Management of post-op cardiac surgery patients
Verify pacemaker settings if the patient is connected to one. Check the chest and mediastinal drainage sumps to ensure they are patent and that the patient is not bleeding excessively. Examine heart sounds.
Listen for murmurs particularly if the patient has had valve surgery. Check all peripheral pulses. Do repeated assessments if there is concern for acute limb ischemia or if the patient has a femoral arterial line or IABP in place. Examine the abdomen. Check pupillary reflexes. Do a more complete neurologic exam when the patient begins to awaken from GA.
Labs and tests Electrocardiogram? Ideally half way between the glottis and the carina. Should be at least one cm above the carina.
Verify correct position of the Swan-Ganz catheter. The tip should not be too peripheral - no more than 1 to 2 fingerbreadths beyond the lateral mediastinal shadow.
Check the position of all other tubes and drains. The ng tube, chest tubes, and mediastinal sumps. Check for pneumothorax. Check for lobar collapse, atelectasis, effusions, pulmonary edema. This can lead to significant hypokalemia and hypomagnesaemia which increases the likelihood of post-operative dysrhythmias.
Standing orders are in place to replace these electrolytes. Glucose - tight glycemic control post-operatively reduces morbidity.
Cardiac surgery: aftercare
They should be assessed as part of the overall clinical picture including the hemodynamic status of the patient and the EKG. Effects of hypothermia Predisposes to ventricular dysrhythmias and lowers VF threshold Increases SVR; increases afterload and myocardial workload Patient shivering causes increased peripheral O2 consumption Decreases CO2 production; a patient who has a respiratory alkalosis low PCO2 on initial ABG usually will increase their PCO2 with rewarming Coagulopathy; impairs platelet function and the coagulation cascade.
Rewarming is an important part of the treatment of a bleeding patient. Bleeding Bleeding can be divided into: "Medical" bleeding secondary to defects in the coagulation cascade, platelets, or fibrinogen; "Surgical" bleeding secondary to operative trauma including leaks at sites of vascular anastomosis or cannulation sites or bleeding from small mediastinal arteries or veins. Surgical bleeding requires a return to the OR for re-exploration and hemostasis.
Surgical bleeding Consider a "surgical" source of bleeding in the following situations: Persistent bleeding in the absence of a specific haemostatic defect normal coagulation parameters Sudden onset of fresh, rapid bleeding; especially if associated with a preceding sudden increase in BP.
Note that repositioning the patient turning on their side may also cause the drainage of a pre-existing collection of "old" darker blood that had pooled in the thorax.
Greater than cc of bleeding in the first post-op hour. The heparin is 'reversed' at the end of the case with protamine. Occasionally, the calculated dose of protamine given is not sufficient to completely reverse the heparin effect.
Patients may also receive additional heparin if they are given back blood that remained in the bypass circuit when the patient was disconnected from CPB "pump blood".