Optimal ICU Management of Postoperative Cardiac Surgery Patients: Techniques, Monitoring, and Complications

• Intensive care and costs for cardiac surgery patients:
  • Intensive care may account for more than one-third of the total hospital costs for cardiac surgery patients.
  • Perioperative events contribute to short-term morbidity and mortality.
• Challenges in the initial days of care for cardiac surgery patients:
  • Life-threatening problems such as low cardiac output, arrhythmias, and coagulopathy may occur during the first 24-48 hours in the ICU.
  • After 48 hours, the problems encountered become similar to those experienced by other critically ill patients.
• History and changing epidemiology of cardiac surgery:
  • The development of modern cardiac surgery is closely linked to the development of the ICU.
  • Advancements in cardiology have reduced the need for surgical approaches except for complex cases or after failed interventions.
  • The population of patients treated with cardiac surgery has changed, with a leveling off and subsequent decrease in the overall number of patients undergoing coronary artery bypass grafting (CABG).
  • Cardiac surgery is being performed on older, sicker, and more complicated patients.
• Alternative techniques for cardiac surgery:
  • Minimally invasive cardiac surgical techniques have been developed to decrease postoperative morbidity, reduce hospital stay, reduce costs, and hasten recovery.
  • Three major techniques are Minimally Invasive Direct Coronary Artery Bypass (MIDCAB), Off-pump Coronary Artery Bypass (OPCAB), and Port Access Technique.
  • Each technique has specific advantages and considerations in patient selection and outcomes.
• Organization of the postoperative cardiac surgery unit:
  • Optimal results from cardiac surgery require a skilled, dedicated, and multidisciplinary ICU team.
  • Patients are admitted to the hospital on the day of surgery and transferred to a step-down unit after 24-48 hours in the ICU.
  • Guidelines outline the requirements for cardiac surgical ICUs, including protocol-driven care, appropriate bed-to-surgery ratio, and one-to-one nursing care during the first night in the unit.
• Surgeon-intensivist relationship:
  • The intensive care specialist must be involved in the continuum of care, working closely with surgeons, anesthetists, and cardiologists.
  • A dedicated intensivist coverage in the ICU has been shown to improve outcomes after major surgeries.
• Separation from cardiopulmonary bypass and the end of surgery:
  • Understanding cardiopulmonary bypass (CPB) is crucial, as operative problems often persist after transfer to the ICU.
  • CPB involves separating the heart and lungs from the systemic circulation to allow surgical repair.
  • Managing a postoperative cardiac surgery patient starts with understanding the technical and pathophysiologic aspects of CPB.
• Cardiopulmonary bypass:
  • During cardiac surgery, a cardiopulmonary bypass (CPB) machine is used to temporarily take over the function of the heart and lungs.
  • The blood is collected from the right atrium, oxygenated, and then returned to the patient via an arterial cannula.
  • The CPB machine allows for myocardial protection and ensures adequate perfusion during surgery.
• Separation from cardiopulmonary bypass:
  • Weaning from CPB involves transferring cardiopulmonary function back to the patient's own heart and lungs.
  • Various measures are taken to restore normal cardiac, metabolic, and respiratory parameters.
  • The surgical team manipulates heart rate, preload, afterload, and myocardial contractility to achieve successful separation.
• Reversal of anticoagulation:
  • After weaning from CPB, protamine is given to neutralize any residual heparin.
  • Dosing may be based on the patient's weight or an assay of residual heparin activity.
  • Possible adverse responses to protamine administration include hypotension and allergic reactions.
• Transport and admission to the intensive care unit:
  • Transporting a critically ill patient to the ICU requires extreme vigilance and continuous monitoring.
  • A detailed sign-out from the operative team ensures continuity of care in the ICU.
  • On arrival, the intensivist-led team assumes patient care and performs a thorough examination.
• Structured handover:
  • Handover from the OR to the ICU should be structured to minimize disruption and maximize communication.
  • Key information includes surgical procedure, complications, ventilation details, and patient monitoring.
  • Thorough examination of the patient should immediately follow the handover.
• Monitoring the postoperative cardiac surgery patient:
  • All postoperative cardiac surgery patients in the ICU have continuous blood pressure monitoring.
  • Hemodynamic monitoring includes assessing cardiac output, central venous pressure, and pulmonary artery pressure.
  • Other monitoring measures include examining the endotracheal tube, chest drains, and pacing wires.
• Arterial Pressure Monitoring:
  • Accuracy of the measurements depends on calibration, leveling, and air removal from tubing.
  • After cardiopulmonary bypass (CPB), femoral arterial pressure may be more accurate, but radial artery cannulation can cause hand ischemia.
  • Vascular complications of femoral arterial lines are rare, but femoral catheters may increase infection risk.
• Central Venous Access:
  • Central venous access is required for drug administration and hemodynamic monitoring.
  • A central venous pressure (CVP) catheter may be sufficient in low-risk patients.
  • Pulmonary artery catheters allow additional measurements, but their use remains controversial.
• Electrocardiography:
  • Patients are connected to continuous ECG monitors and 12-lead ECGs are obtained.
  • Arrhythmias should be treated using established protocols.
  • ST-segment changes should be investigated if persistent, potentially leading to further revascularization.
• Chest Radiography:
  • Postoperative chest radiographs confirm proper placement of tubes and note pneumothorax or consolidation.
  • Enlarged cardiac silhouette or pleural effusions may indicate ongoing bleeding.
  • Abnormalities are detected in up to 35% of patients, but few require therapy change.
• Echocardiography in the ICU:
  • Echocardiography is used to evaluate chamber size, valve repair, tamponade, and new ischemia.
  • Transesophageal echocardiography (TEE) is particularly useful in managing postoperative hypotension.
  • TEE impacts therapy decisions in 73% of cases by changing treatment or confirming no intervention is needed.
• Unique Challenges in Image Optimization:
  • Image optimization is challenging due to mechanical ventilation, dressings, and diagnostic findings.
  • Clear visualization of all cardiac chambers is necessary to detect pericardial hematoma or massive hemothorax.
  • RV dysfunction may occur in isolation and patient-prosthesis mismatch can complicate weaning from ventilation.