Fellow’s Reference for ECMO-related Queries
Prepared by Alvey, Abu-Sayf, Al-Jasmi, Razvi, Abrencillo
| Problem | Symptoms/Signs | Differential | Possible Solutions | Who to involve |
|---|---|---|---|---|
| Decreasing Patient PO2.Think of:Increase O2 consumption, decrease O2 delivery, decrease exchange
As a general rule an arterial Sats of 85% patients on VV ECMO is acceptable if the patient is perfusing (no worsening organ dysfunction, not forming lactate) |
CyanosisAcidosisLethargyPoor perfusion
Worsening PO2 and O2sat on ABG
Patient looks well
|
Problems related to Increase O2 consumption: Seizures, Sepsis, AgitationProblems related ECMO:
Inadequate blood flow, Sweeper gas line malfunction, Oxygenator failing, FiO2 of sweep gas low
Problems related to the Native lung: Pneumothorax, ET tube malfunction, pleural effusion, hypervolemia, increased shunting
Problems related to CO: Abdominal compartment, decreased CO, Pericardial tamponade, Suspected cardiac shunt vs valvular defect, acute right heart failure,
O2 carrying capacity: Anemia, Methemoglobinemia (from NO or Nitroprusside)
Recirculation: Most common in Jugular-Femoral and Femoral-Femoral VV circuit .Least common in Femoral- Jugular VV circuit
Improved CO (Hemodynamics is improved therefore pushing more blood to the recovering lung) |
Treat underlying cause
Increase the flow, Replace or fix the line, Replace the oxygenator, Increase FiO2
know the native lung parameters and compliance before the acute event, resting lung strategy may worsen hypoxemia and increase shunting and pulm pressures Diuresis, reintubation, increasing PEEP or FiO2, extreme caution on invasive procedures
Review the last echo and the Arterial line parameters before the event Consider repeating Echo and vasopressors, consider possible conversion to VA ECMO
Although the cardiac literature asks for Hb > 10, there is no data to support against or for transfusion with Hb < 7.0 unless it is a method to increase CO. Transfusion of prbc, methylene blue
Consider switching circuit or even adding another venous line. AVLON catheter might be considered.
Consider ECMO weaning |
Fellow/Primary team with RT to make medical decision involving increasing vent supportCall Perfusion and CTS for gas, recirculation and oxygenator problem
Before placing any tubes (catastrophic bleed), if stable, please contact CT surgery. If unstable, call CVICU, team to help out
Call CT surgery if lines needed to be added or changed |
| PO2 is increasing | CyanosisAcidosisPoor perfusionHemodynamic instability
Patient is looking well |
Problems related to O2 consumption/delivery: Sepsis with peripheral shunting, tissue death with decreased O2 consumption, central shunting Problems related increasing ECMO flow secondary to decrease CO:
MI, cardiac stunning, cardiac tamponade (air,fluid), Lung (air,fluid), hypovolemia
Improving native lung compliance (better TV, lower pressures)
Cardiac stunned with adequate VA flow |
Treat the underlying reason, monitor clinically for fasciitis, gangrene or worsening sepsis, central shunt is hard to treatTreat underlying cause, increase ECMO flow, consider converting to VA, administer volume or blood
Consider lowering FiO2 on the ECMO and start weaning
Continue ECMO Full support |
Before placing any tubes (catastrophic bleed), if stable, please contact CT surgery. If unstable, call CVICU, team to help out
|
| Decreasing CO2 | Patient is apneic and alkalotic
Patient tachypneic |
CO2 in sweep gas too lowSweep gas flow too high
Overventilation
Improving lung function
CO2 in sweep gas is too high or Sweep gas flow too low (acidemia with compensatory tachypnea)
Underventilation
|
Increase CO2 in sweepDecrease flow
Adjust vent settings to decrease MV
Check compliance on vent and ABG while on 100% FiO2 (Cilley Test) on vent to assess lung recovery à consider weaning
Decrease CO2 in sweep gas or Increase gas flow
Ensure ETT in position Adjust vent to increase MV |
Call Perfusion to adjust CO2 in the blender or to change the flowCall RT for Vent changes |
| Increasing PCO2 | Tachypnea, acidosis, agitation, hypertension | Oxygenator failureCO2 in sweep gas too high or Sweep gas flow too low
Patient agitated
Increased metabolic activity
ETT positioning problem and/or Increasing airway pressures in ventilator
|
Look at oxygenation, delta P across membrane (prob clot if high)Decrease CO2 in sweep gas or decrease gas flowAddress source of agitation
look for signs of sepsis, overfeeding
Adjust ET and/or look for pneumothorax, hemothorax, effusion |
Call Perfusion to adjust CO2 in the blender or to change the flowCall RT for Vent changes |
| Coagulation problems – difficulty maintaining PTT | Too High
Too Low |
Error in lab testing, lab was drawn incorrectly, error in heparin dosingDecrease in coagulation factors
DIC
Lab error, collection error, dosing error
Recent transfusion of blood products
Heparin resistance |
Double check heparin dose, location lab was drawn, etc.Assess for Vit K deficiency, liver dysfunction, consumptive coagulopathy
r/o sepsis, r/o circuit coagulopathy (diagnosis of exclusion)
Double check heparin dose, location lab was drawn, etc.
Recheck PTT after completion of transfusion
Assess for antithrombin deficiency (esp in malnutrition, liver/renal failure) and supplement with FFP or factor concentrate; look for drug interactions
|
RN and Pharmacy for additional blood draws/ work-up and for dosing error respectivelyIf circuit is cause – call Perfusion and CT surgery for a circuit change |
| Bleeding | Visible bleeding, expanding hematoma, drop in Hgb, MAPs decreased, signs of hypoperfusion | Coagulopathy: iatrogenic from anticoags vs consumptic (DIC vs circuit).Bleeding from surgical site
hypertension |
Decrease heparin dosing Assess for sepsis, circuit coagulopathy (diagnosis of exclusion)Hold pressure. Consider Amicar, FFP, platelets
control BP |
Call CT surgery.Coordinate with CVICU team for threshold of transfusion |
| Hemolysis | Plasma free hemoglobin > 50 mg/dl, Tea colored urine | Pump Over occluded, clots in patient, clots or kinks in system, centrifugal pump issue | Change pump and inspect for clots in kinks in circuit, hemofilter or patient | CT surgery and Perfusion to help with possibly changing lines or pumps respectively |
| Hypertension | Increased BP | Fluid overload, pain, agitation, idiopathic, improved Cardiac Output(VA ECMO), high pump flow(VA ECMO), steroid use | Diuretics/CVVHD, treat pain, sedatives, anxiolytics, Anti HTN meds, Decreased ECMO flow | MICU team |
| Hypotension | Decrease BP | Massive HemorrhageHypovolemia, capillary leak syndrome, sepsis
Low pump flow |
Emergency!!! Supportive resuscitationTreat underlying cause
Increase pump flow if adequate arterial volume |
For massive bleeding CVICU to be involved STAT and CT surgery to be involved immediately |
| Arterial line tracing flat (loss of pulsatility) | VA ecmo: patient well perfusedVA ecmo: patient not perfusing
VV ecmo: not good |
Too much ecmo support or profound depression of COCode or precode situation
Code or precode situation |
Maybe appropriate if “resting” the myocardiumNO chest compression
ACLS |
If patient is sick, all services should be notified and critical care team at bedside |
| Decreased Urine Output | Oliguria/anuria | Hypotension, Hypovolemia, decreased CO, ATN | Treat underlying cause, might need to augment CO (watch out for hypoxia i.e. more de-oxgenated blood pushed to sick lung), consider HD | MICU team in coordination with CT surgery if planning to place a dialysis catheter |
| Seizure | Repetitive involuntary movements, Increased BP, Decreased SVO2, Cyanosis, Hypoxia | Ischemic brain injury, Cerebral edema, Infarction, Intracranial hemorrhage | Anticonvulsants, treat the underlying cause. Must rule out brain bleed | MICU team |
| Oxygenator Failure | Low pump atrial PO2, Decreased PCO2 clearanceIncreased pressure gradient across membrane (normal delta P = 20 to 40mmHg). Leads to hemolysis, elevated fibrin split products, worsening thrombocytopenia | Low FiO2, high PaCO2, Sweep gas line to oxygenator is loose, disconnected or crackedOxygenator Clotting off, air in the top of oxygenator or blood leaking from the exhaust gas port due to membrane leak or complete rupture
Oxygen rated flow/Efficiency exceeded
|
Increase FiO2 and check oxygen tank, increase sweep Gas if not at maximum, reattach gas line to oxygenatorReplace oxygenator
Check manufacture rated oxygenator flow and decrease blood flow if indicated |
Involve Perfusion for replacement of oxygenator or increase change gas setting |
| Low Flow | Negative pressure alarm(Bladder or venous line pressure alarm)
Positive pressure alarm (oxygenator alarm) |
Venous/Cephalic catheter malposition or kinked, clot in the systemIntravascular volume depletion
Inadequate venous return due to patient condition(pericardial tamponade, pneumothorax, increase IA pressure)
Pressure alarm limit set too low, pressure transducer malfunction, flow is adjusted too high
Malposition and kinks in the tubing/cannula, Clot in oxygenator system, clot in art line filter, wrong alarm setting, alarm malfunction |
Catheter needs to be repositioned, check for clotsConsider fluid bolus
Address the underlying issue. Can bolus in the meantime
Adjustment of alarms, flush transducer, lower flows
Remove kinks, check cannula position, inspect for clots and replace as needed, check alarm settings |
Call CT surgery for readjustmentBefore placing any tubes (catastrophic bleed), if stable, please contact CT surgery. If unstable, call CVICU, team to help out
Call Perfusion for alarms and flow adjustments
|
| Exchanger water heater | Blood in water line
Water dripping
Temperature alarm: Consider if patient is cold or Hot ( patient will usually follow the temp set it ECMO)
|
Crack in heat exchanger water/blood sealLeak
Temp set wrong, heater pump malfunction, large amount of cold water adder to reservoir, tem adjusted, water level low, consider new fevers
|
Emergency!!! turn off the heater immediately, replace the heat exchangerChange circuit
Check set temperature, replacement of water heater, add water to heater, check exhaust fan, check connections and plugs of water heating unit
|
Involve Perfusion as soon as possible if blood is in the water line |
| Air in Circuit | Preoxygenator(air in venous line)Oxygenator
Post-Oxygenator
Arterial Line |
Open/Cracked stopcocks, connectors in venous linesAir from IV infusion, air leak (venous line oxygenator, bladder), priming problem
Air from IV infusion lines, leak from venous line passing through oxygenator, gas outlet obstruction
Massive air pumped from venous side |
Air aspiration from bladder, top of oxygenatorAir aspiration (risk of embolism), oxygenator replacement, monitor for recurrence
Aspirate, stop airleak, replace oxygenator, calmp ECMO if risk of air reaching the patient
VA ECMO Emergency!!! arterial line needs to be manually kinked to stop air flow into arterial system |
Any Air in the system, Perfusion needs to be involved |
| Pump Failure | Pump without power, Pump shutting offoverheated pump
Pump rotating but no flow
|
Unplugged, battery malfunction, specific switches off, unsecured lids, alarms and knobs not in proper settingWet connections
Malfunction, inadequate seal |
Check connections, use portable power supply, hand cranking , reset the system, check for air and switchesCheck connections
Adjust occlusion/seal |
Involve Perfusion STAT |
| Negative Pressure Monitor Failure at the bladder box (venous blood reservoir) | Cavitation (space free of fluid) as pump turns Pump not stopping when venous line clampedNo alarmsBlood on floor |
Obstruction just after bladder (kicks or clots), malfunction of bladder or pressure transducer
Equipment or wrong alarm threshold
Leak in bladder |
Inspect for obstruction prior to pump, change bladder, re-zero pressures, inspect pressure transducer lines, Change bladder | Ask nurse to inspect for clots close to the bladder. Call Perfusion to inspect bladder, lines and pressure settings |
| Pump Failure | Pump without powerPump shutting off
overheated pump
Pump rotating but no flow
|
Unplugged, battery malfunction, specific switches not onUnsecured lids, alarms and knobs not in proper setting
Wet connections
Malfunction, inadequate seal |
Check connections, use portable power supply, hand crankingReset the system, check for air and switches
Check connections
Adjust occlusion/seal |
Involve Perfusion STAT |
| Negative Pressure Monitor Failure at the bladder box (venous blood reservoir) | Cavitation (space free of fluid) as pump turns Pump not stopping when venous line clampedNo alarmsBlood on floor |
Obstruction just after bladder (kicks or clots), malfunction of bladder or pressure transducer
Equipment or wrong alarm threshold
Leak in bladder |
Inspect for obstruction prior to pump, change bladder, re-zero pressures, inspect pressure transducer lines, Change bladder | Ask nurse to inspect for clots close to the bladder. Call Perfusion to inspect bladder, lines and pressure settings |
Glossary of Terms
Sweep gas: determines CO2 elimination. CO2 elimination is dependent Fresh gas flow rate but independent on blood flow rate
Flow rate: determines oxygenation. Oxygenation is dependent on blood flow rate but not fresh gas flow rate
Bladder Chamber: a reservoir for blood before the pump used to catch air and help provide constant volume to the pump
Centrifugal pump: imparts centrifugal force to fluid/blood causing increase in pressure and kinetic energy radially. This ultimately cause displacement of fluid which creates a suction effect
Oxygenator: “external lungs”; this is where gas exchange happens. The system is usually divided to pre and post oxygenator
Oxygen rated flow: manufacturer-set-predicted PaO2 on post oxygenator blood at a given flow and hemoglobin
Delta P: Pressure gradient across the oxygenator (pre and post).
Re-circulation: blood that goes around the circuit and not delivered to patient
Chattering: Low amplitude shaking of tubes representing high variation in flow
Cavitation: intermittent collapse of the vessel which may lead to hemolysis
Cilley Test: Increase FiO2 to 1.0 with no other changes. Positive test is rapid increase to SaO2 100%