Cardiac ICU Flashcards
Q:
What is the management protocol for atrial fibrillation post-operatively?
-Potassium (K⁺): Administer 10–20 mmol K⁺ via a central line to achieve a serum K⁺ level of 4.5–5.0 mmol/L.
-Magnesium (Mg²⁺): Give 20 mmol Mg²⁺ via a central line if not already administered post-operatively.
-Amiodarone: For patients with good left ventricular (LV) function, administer 300 mg amiodarone IV over 1 hour, followed by 900 mg IV over 23 hours.
-Digoxin: For patients with poor LV function, give digoxin in 125-microgram increments IV every 20 minutes until rate control is achieved, up to a maximum of 1500 micrograms in 24 hours.
-Synchronized DC Cardioversion: Use for unstable patients (consult specific graphics for technique).
Q:
What actions should be taken in response to excessive bleeding?
A:
- Immediate Help: Get immediate assistance if bleeding exceeds 400 mL in 30 minutes.
-Fluid Resuscitation: Administer colloid to achieve a central venous pressure (CVP) of 10–14 mmHg and a systolic blood pressure (BP) of 80–100 mmHg.
-Blood Products: Order 4 units of blood, 2 units of fresh frozen plasma (FFP), and 2 pools of platelets.
-Diagnostics: Send coagulation studies and complete blood count (CBC); request a chest X-ray (CXR) stat.
-Transfusion Targets: Transfuse to achieve hemoglobin (Hb) >8.0 g/dL, platelets >100 × 10^9/L, and activated partial thromboplastin time (APTT) <40 seconds.
-Medications: Administer empirical protamine 25 mg IV; consider desmopressin (DDAVP®) if indicated.
-Re-exploration: Emergency re-exploration is indicated for persistent excessive bleeding.
Q:
What steps should be taken in the event of profound hypotension?
A:
-Immediate Help: Get immediate assistance and verify the accuracy of the reading.
-Assessment: Quickly assess pulse, rhythm, rate, central venous pressure (CVP), oxygen saturation, and check for bleeding.
-Cardiac Arrhythmias: Defibrillate for ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT); treat atrial fibrillation (AF) as previously described.
-Bradycardia: Treat with atropine 0.3 mg IV or consider pacing.
-Fluid Resuscitation: Administer colloid to raise CVP to 12–16 mmHg and place the bed in a head-down position.
-Cardiac Tamponade: If suspected, prepare for re-sternotomy.
-Vasodilation: If the patient is warm and vasodilated, administer 10 micrograms of metaraminol in 10 mL saline, giving 1 mL through a central line and flush.
-Persistent Hypotension: If still very hypotensive, repeat metaraminol administration or give 1 mL of 1:10,000 epinephrine IV and start a pressor infusion, such as norepinephrine at 0.1 mcg/kg/min.
Q:
What steps should be taken if the patient’s oxygen saturation (sats) is <85% and falling?
A:
- Immediate Help: Get immediate assistance.
- Increase FiO2: Temporarily increase the fraction of inspired oxygen (FiO2) to 100% and check the pulse oximeter.
-Assessment: Assess lung expansion, auscultate the chest, and check arterial oxygen partial pressure (PaO2).
-Tension Pneumothorax: If suspected, treat immediately (refer to graphic for details).
-ET Tube: Suction the endotracheal (ET) tube and ensure the patient is not biting it.
-Drainage: Check that drain tubing is patent and drains are on suction.
-Bronchospasm: Treat with albuterol 2.5 mg via nebulizer.
-Manual Ventilation: Disconnect from the ventilator and hand-ventilate the patient.
-Chest X-ray: Obtain a CXR to check for pneumothorax, hemothorax, atelectasis, ET tube position, and lobar collapse, and treat accordingly (refer to graphic for details).
Q:
What is preload and why is it difficult to quantify directly?
A:
Preload is a measure of the wall tension in the left ventricle (LV) at the end of diastole. It is challenging to quantify directly due to the complexity of assessing the exact ventricular stretch and pressure changes.
Q:
What is afterload and what does it measure?
A:
Afterload is a measure of the wall tension of the left ventricle (LV) during systole. It reflects the resistance the LV must overcome to eject blood during contraction.
Q:
What factors determine afterload?
A:
Afterload is determined by:
-Preload: The maximum ‘stretch’ of the heart muscle before contraction.
-Resistance Against Ejection: Includes systemic vascular resistance (SVR), vascular compliance, mean arterial pressure, and any left ventricular outflow tract (LVOT) pressure gradient.
