(Written with assistance from Thomas Doyle, MS, CCP)
CPS used by EMS …
An interesting paper on using expanding percutaneous cannulas with CPS.
Click to read article…
Procedure for CPS
A. Disposable Equipment:
1. CPS Pack
2. Percutaneous cannulae (arterial/venous)
3. Membrane oxygenator with integral heat exchanger and holder.
4. Disposable centrifugal pump head
5. Disposable flow probe
6. Balanced electrolyte solution
7. Heparin (access to NaHCO3, Mannitol, and CaCl2 is advised)
8. Perfusion flow sheet/pump record
9. Anticoagulation Test Supplies
1. Centrifugal pump console
2. Flow transducer
4. ACT machine/anticoagulation monitor
5. O2 cylinder
6. Tubing clamps
7. Mobile cart with blender / IV pole / power supply
B. Procedure for Implementation:
1. Turn pump console off.
2. Clamp prime line.
3. Clamp line between the prime line and the double sash wrapped A-V loop.
4. Clamp line between the double sash wrapped A-V loop and the oxygenator outlet.
5. Open sash wrap, hand tubing onto the table, and securely fasten coil of tubing to the table.
6. Identify the venous line (inlet to the pump head) and the arterial line (outlet from the oxygenator) and have physician or scrub nurse/technician clamp and divide the A-V loop on the sterile field.
7. Attach the venous line to the venous catheter. Attach the arterial line to the arterial catheter.
8. Remove clamps on the venous line.
9. Turn the pump console to approximately 1200 RPM’s.
BE SURE THE HEATER/COOLER IS STILL RECIRCULATING AND THE PRIME IS WARM. IF PATIENT IS AWAKE, THEY WILL FEEL IT IF THE PRIME IS COLD.
10. Remove the arterial clamps slowly and initiate flow.
11. TURN GAS FLOW ON TO APPROPRIATE MINUTE VENTILATION. If the patient was being ventilated, you can assess this requirement with anesthesia.
12. Slowly increase the RPM’s and the flow until adequate support has been established as evidenced by arterial blood gases, blood pressure, etc.. It is crucial that close hemodynamic monitoring be carried out during the initiation period.
THE PRIME LINE SHOULD BE DOUBLE CLAMPED AT ALL TIMES DURING BYPASS. IF FLUID IS TO BE ADDED TO THE PATIENT IT CAN BE DONE SO THROUGH THIS LINE. TO ADD ADDITIONAL PRIME SOLUTION OR FLUID TO THE PATIENT, SLOWLY REMOVE THE CLAMP ON THE PRIME LINE AND ALLOW FLUID FROM THE BAG TO ENTER THE SYSTEM THROUGH THE PRIME BAG. (CARE SHOULD BE TAKEN TO ENSURE THAT ALL THE AIR IS OUT OF THE BAG AFTER THE SPIKE HAS BEEN PLACED IN THE BAG. THIS WILL PREVENT THE INADVERTENT POSSIBILITY OF AIR ENTERING THE SYSTEM THROUGH THE BAG PRIME PORT SYSTEM.)
C. Procedure for Patient Management:
The percutaneous cannulae are designed to be introduced into the femoral arteries and veins by use of the Seldinger technique. These cannulae should have flexible vessel dilators, be wire reinforced, thin wall design, and have a smooth surface for non-traumatic introduction into the vessels. The cannulation kit should include vessel dilators, guidewires, thin wall needles and a scalpel. The venous cannulae should be of sufficient length to reach the right atrium (usually 50-60 cm.). Currently there are several manufacturers that produce such cannulae. These include but are not limited to: DLP, Bio-Medicus, Research Medical INC., and Bard Cardiovascular.
B. Anticoagulation :
Before going on CPS, the target ACT is 400 seconds. Once on CPS, the ACT should be maintained at 480 seconds or above. Anticoagulation monitoring should be carried out in the standard fashion for your institution.
Flows for CPS are and should be based upon individual patient requirements. Limits to such flow may be seen due to inadequate venous return. Every effort should be made to achieve a cardiac index of 2.2 L/min/m2.
D. Monitored Parameters:
1. The patient must be appropriately monitored (ECG, arterial, pulmonary artery, and venous pressures). Since the initial period on CPS is very dynamic, adequate supplies for volume replacement (packed cells, FFP, colloids) should be available in the room and during transportation (if done). A defibrillator and medication infusion pumps are also required.
2. Lab values should include, but are not limited to the following: CBC, SMA-7, PT, PTT, fibrinogen, fibrin split products, ACT, serum osmolality, oncotic pressure (if available), albumin, and total protein
1. Prior to termination, an accurate measurement should be made of anticoagulation status. If the case has been performed with little or no heparin (in the presence of a heparin bonded circuit), you should consider raising the ACT to approximately 180-200 seconds and the aPTT to 1.5 times normal. Be sure the hematocrit has been optimized as myocardial oxygen consumption will increase dramatically during the weaning process. This being the case and especially in the presence of right heart failure, hematocrit greater than 35% would be preferred to increase the O2 content and carrying capacity.
2. Termination of CPS will be carried out upon orders from the attending physician. It will be done in a step-wise fashion of decreasing flow and allowing the patient to progressively resume his native cardiac filling cycle and cardiac output. Both the venous and arterial lines should be clamped once it is decided that the weaning procedure has been completed. When the surgeon has decided that the heart can support the required cardiac output, the CPS cannulae are removed from the patient in the SICU or operating room under strict aseptic technique.
1. If the patient is to be transferred while on the CPS system, a portable power supply for the pump console is essential. (Most pumps have a built in battery pack. Be sure it is fully charged prior to transport.) The handcrank should be available during transportation in the event of a battery malfunction (the interruption of the CPS flow should be treated as a cardiac arrest or failure and treated as such).
2. Advance planning as to the size of doorways, areas required to make turns around corners, width of beds, length and width of elevators will save frustration and time during the actual move of the patient. The patient may be on the intra-aortic balloon pump, so the space required to move through the halls, doorways and into elevators is sometimes more than what is available.