ECMO Safety Checklist

Resus Review

Safely managing an ECMO patient requires a special level of compulsiveness and thoroughness. This is the responsibility of everyone caring for an ECMO patient including nurses, perfusionists, respiratory therapists, physicians, and surgeons. To help minimize errors and safety risks during shift change, a detailed checklist was developed to help facilitate communication and ensure that all equipment is functioning well.

The ECMO checklist is broken into two parts. The first involves communicating the patient’s condition and review of the data. The second phase, is a detailed inspection of the patient and equipment performed at the bedside.

It is useful to have a copy of the safety checklist and paper record as you perform the sign out so that the any findings can be documented immediately. This helps prevent forgetting items that can occur if the documentation is done later. I also recommend that the checklist be performed in a consistent pattern to help avoid missing items and help speed the process because everyone is familiar with the process.

Patient and Data Review

As with any ICU patient sign out, a lot of detailed and technical information needs to be conveyed as efficiently as possible. When the patient is ECMO, there is even more to think about and understand. So in addition, to routine data, special attention to ECMO parameters and data needs special attention.

ECMO Safety Data Review Checklist

  1. Patient’s condition and problem list.
  2. Vital signs and trends.
  3. Current infusions (eg. vasopressors, inotropes, maintenance fluid, tube feedings, sedation, etc).
  4. Flow settings and pump speed.
  5. Sweep gas flow rate and fraction delivered oxygen (FDO2).
  6. Ventilator settings.
  7. Recent labs. At minimum this should include pre/post oxygenator ABG, hemoglobin, platelets, lactate, bilirubin.
  8. Pre/post oxygenator pressure.
  9. Any flow issues.
  10. Anticoagulation (heparin gtt, bivalirudin, ACT, etc).
  11. Current type/cross is up to date and emergency blood supply available in blood bank.

Inspection

Once all of the data review checklist has been completed, the patient and equipment should be inspected at the bedside by both the off-going and on-coming person together. Doing this with each other allows for for two sets of eyes to perform the inspection and confirm that all of the checklist items are addressed. It also helps to identify if abnormal findings are new or changing.

Bedside ECMO Safety Inspection Checklist

  1. Ensure tube clamps are available and at patient bedside. We typically keep four clamps available, and the are hung on the pump cart. A standard location is important, so that that when needed, which is almost always an emergent situation, everyone knows where to grab them.
  2. Inspect catheter. Observe that it is positioned properly, securing sutures are in place, dressing is in place, and that there are no signs of infection, drainage, or bleeding.
  3. With flashlight observe entire length of circuit. Look for any cracks in tubing or fibrin clot formation. Identify any areas where leakage may be occurring.
  4. Observe oxygenator for any clots, fibrin formation, or air accumulation. Ensure that the yellow cap is in place, and that there is no plasma drainage. Check tightness of the blood, heated water, and air connections.
  5. Look at the ECMO pump for any air or chatter. Listen for any unusual sounds. The pump should be well seated in the cradle. The emergency hand pump should be tested and that the RPM indicator is working.
  6. The flow sensors should be attached and lubricated.
  7. Ensure heater is on and connected. Verify the set water temperature. The water tank should be full.
  8. Correct settings on the blender for the sweep gas flow rate and fraction delivered oxygen (FDO2).
  9. Verify gas supply. Gas modules connected to proper wall sources. Reserve tank is full, and the valve and wrench are attached.
  10. Zero the pressure transducer.
  11. ECMO support cart at bedside and properly stocked. See this post for list of supplies kept in the support cart.
  12. Emergency ventilator settings posted.
  13. If applicable, the CRRT circuit and parameters should be inspected at the same time.

The safety checklist items should be documented either on a paper flow sheet or in the electronic medical record.

ECMO Safety Checklist

Pediatric Supraglottic Airways

Resus Review

Pediatric airway management is one of the most stressful and fearful activities within the emergency department. We use these skills less often as compared with adults, and therefore the familiarity, mental and muscle memory are not as tuned. There is also a tremendous cognitive load during pediatric resuscitations determining the appropriate sized equipment and medication dosing, increasing the pressure.

There are numerous critical differences in managing the pediatric airway. There are anatomical differences, especially in children <2-years of age. The child’s head is much larger in proportion to their body than adults, with a large occiput which often requires position of padding behind the shoulders. The airway is also very anterior to what you are used to in adults. Given the small size of the airway, they tend to obstruct much easier, and the stimulation and pain of a resuscitation can lead to dynamic obstruction. There are physiologic differences. Child have a much higher base line oxygen consumption rate than adults and small proportional functional reserve capacity (FRC) which leads to quicker desaturations. Lastly, all medications require weight-based dosing.

While BVM ventilation, direct/video laryngoscopy (including the speciality pediatric blades) are foundation of managing the pediatric airway, the primary backup airway adjunct are the supraglottic devices. In some situations they may be useful for primary BVM ventilation.

Supraglottic airways (ie SGA, Laryngeal Mask Airway, LMA) are available in non-intubating and intubating pediatric sizes. They are sized by patient weight (which is on the device packaging) from newborn to adolescent. The reason for having both intubating and non-intubating SGAs is because both types have unique features that may be critical in a given situation. Below we will discuss which device to choose and why.

Non-intubating LMA Supreme

With infants, we can usually provide adequate Bag-Valve-Mask ventilation with an appropriately sized face mask easily. In a short time however, the stomach becomes insufflated which compresses the lungs and makes it difficult to provide adequate ventilation. This is the main problem we get into with infants.

When you are having trouble with face mask ventilation and/or the patient’s stomach is inflating during face mask ventilation, pick the non-intubating LMA Supreme and use the gastric port to empty the air out of the stomach as ventilation is ongoing. This approach allows us to ventilate through the LMA for a prolonged period without inflating the stomach. Simply remove the LMA when you have provided enough preoxygenation based on the oxygenation saturation level, and attempt your intubation. I think this is the greatest use for peds LMAs, so get used to this device. You can also use this device as the initial first-line ventilation device (instead of BVM ventilation) for newborns and infants, since it usually provides better ventilation than BMV.

They are available in sizes 1, 1½, 2, and 2½.

LMA Supreme Side View

LMA Supreme Oblique View

At the top of the LMA Supreme are two ports. There is a standard 15mm ID x 22mm OD adaptor that connects to a BVM or ventilator. There is also a separate channel for a suction catheter that leads to the esophagus.

LMA Supreme Suction Port View

The figure below shows a detailed view of the mask. At the tip of the mask you can see the exit port for the gastric suction catheter. Notice that the cross-section of the air exit port in post has an upside down U-shape to accommodate the channel for the suction catheter. This makes it difficult to pass a bougie or intubating catheter through.

LMA Supreme Mask Detail View

air-Q Intubating LMA

For a pediatric patient with difficult airway anatomy in which you want to intubate with a bronchoscope, then the preferred approach to use is the intubating air-Q LMA. This device has been tested head-to-head against other pediatric supraglottic airways and is able to accept an appropriately sized endotracheal tube for all patient sizes.

air-Q Intubating LMA Side View

Notice in the photo above, that there is no inflation mechanism (ie syringe adaptor, pilot balloon, and connector tubing). The model shown is self-pressurizing, designated as the “air-Qsp”. The mask is connected to the airway conduit, so it is inflated every time inspiratory pressure is applied either by a BVM or ventilator. It the becomes deflated during exhalation. The theory is that this prevents over-inflation of the mask causing high cuff pressures and subsequence mucosal injury.

In the oblique view below you can see the large bowel, epiglottis elevator/stabilizer, and central channel that allows for ventilation and passage of an intubating endotracheal tube. Unfortunately, as compared with the LMA supreme there is no suction port.

air-Q Intubating LMA Oblique View

A unique feature of the air-Q intubating LMA is the removable cap. With cap attached, it is a standard 15mm adaptor. When you disconnect the cap, the central channel is exposed which allows for passage of the endotracheal tube.

air-Q Intubating LMA Cap

air-Q Intubating LMA Top View

Blind intubation through these devices can be difficult, so I would not recommend it especially in an unstable patient. Use a pediatric bronchoscope. They have a diameter of 4 mm and can fit through a 4.5 or larger endotracheal tube. If your patient can handle a 4.5 ET tube (about 12 months of age and above), you now have a way to intubate in a controlled manner using a bronchoscope.

Push rods for removal of the air-Q LMA after intubation are available, but it is generally easier and faster to just use a second ET tube as a push rod.

Fastrach Intubating LMA

The Fastrach Intubating LMA is available in a size 3, which is useful for older children. it is indicated for patients weighing 30-50 kg (approximately age 10-14). The rigid shape works extremely well for seating the mask in the hypopharynx, and is reuseable. It is my preferred intubating LMA for adults and preteens.

Fastrach Intubating LMA Size 3

Airway Cart

Given the need for various sized tube, a well planned airway cart is a must for fast access and ease of restocking. The figure below is the pediatric airway cart in our pediatric resuscitation bay. It contains all of our equipment, and is labelled so that missing items can be quickly identified and restocked.

Pediatric Airway Cart

We have arranged the top drawer of the cart to contain the supraglottic airways. It contains the four available sizes of the air-Q LMA, and five sizes of the LMA supreme. It also has a size 3 Intubating Fastrach LMA. As you can see, any misisng devices are easily identifiable.

Pediatric Airway Cart Top Drawer with Supraglottic Airways

Conclusion

As we know from our experience with the ILMA in adults, having these devices readily available (and knowing how to use them) is critical to optimizing the safety of pediatric airway management. I highly encourage using these devices on straightforward patients before you are forced to use one in a difficult or failed airway.

For additional airway tips and techniques, please visit HQMedEd.com. Courtesy of Rob Reardon, MD, Hennepin County Medical Center.

Pediatric Supraglottic Airways

ECMO Ultrasonic Flow and Bubble Sensor

Resus Review

A crucial component of ECMO circuits are the flow sensors. At minimum, they provide measurement of blood flow rate and bubble detection. Newer sensors can also estimate hematocrit and oxygen saturation. The flow sensor is incorporated into the downstream side of the centrifugal pump. An additional clip-on sensor is sometimes included downstream of the oxygenator. In more advanced compact systems such as the Maquet CARDIOHELP, the sensors are built into the pump/oxygenator disposable component.

ECMO Ultrasonic Flow Bubble Sensor

Blood Flow Sensor

With positive displacement pumps, the blood flow flux through the pump is determined solely by the pump speed. However, with centrifugal flow pumps that rotate at set speeds, the flow rate through the pump also depends on the upstream and downstream pressures. Therefore, an external sensor is required to provide the blood flow rate information.


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The sensors work by by measuring the transit-time of ultrasonic pulses through the blood flow. The flow sensor surrounds the ECMO circuit tubing. Ultrasonic impulses are sent from one piezo crystal to another (either directly in an X-pattern or by a reflector with the crystals acting alternately as transmitters and receivers depending on the manufacturer). The transit time taken by each impulse is determined, and the differences times taken by the impulses flowing upstream and the ones flowing downstream are proportional to the flow rate.

ECMO Ultrasonic Flow Sensor Doppler Transit Schematic

Even though the physical path lengths of the ultrasound beams within the the sensor are the same, the transit time is longer for the beam going upstream is longer because of the Doppler effect. An object moving towards the ultrasonic beam compresses the wave, thereby increasing the signal’s frequency, whereas an object moving away from the beam reduces the signal’s frequency. The change in frequency, which is also termed the Doppler shift, provides information about the object’s speed and direction of motion.

Bubble Detection Sensor

Bubble detection is critical to maintain the steady-flowing circuit and prevent complications from air embolism especially with veno-arterial ECMo circuits. Non-invasive ultrasonic bubble sensor uses an active piezoelectric element as a piezoelectric transmitter to generate a high frequency acoustic wave. This acoustic wave travels through the sensor wall and is coupled (using coupling paste) to the tubing that is in contact with that wall. The wave then travels through the fluid-filled tubing to the opposite sensor wall and is received by a passive piezoelectric element on the other side (left figure below).

The ability to sense when air is present is due to the large acoustic impedance difference that exists between the tubing wall or fluid and air (right figure below). This large impedance mismatch creates an acoustic mirror which reflects the ultrasonic wave back in the direction of the transmitter. Since energy does not reach the receiver side, the sensor will indicate the presence of air.

ECMO Ultrasonic Bubble  Detector Acoustic Window      ECMO Ultrasonic Bubble  Detector Acoustic Mirror

Blind spots are areas within the tubing that do not lie in the acoustic path. Since they are not in the acoustic path, air bubbles that pass through these locations do not attenuate the acoustic signal and will go undetected. Most orientations are likely to detect bubbles under rapid flow conditions because fluid flow tends to center the bubble. However, under low flow conditions buoyancy will apply a force against gravity, potentially locating a bubble in a blind spot area. A horizontal sensor with vertical tubing, allows for a drifting bubble to travel faster and center itself within the tubing.

Another method for optimizing bubble detection is to clamp the tubing into the sensor channel to compress it to more of a square shape. This maximizes the acoustic window, and minimizes the blind spots which reduces the risk of undetected bubbles. This method also minimizes the effects of pressurized tubing which is important on the outflow side of a veno-arterial ECMO circuit. This method may not always be practical, but is highly recommended when possible.

ECMO Ultrasonic Flow and Bubble Sensor

Prone Positioning Tips and Checklist

Resus Review

The Rise of Prone Positioning

Prone positioning has transitioned from a salvage procedure for ARDS, to a more routine part of the armamentarium based on the dramatic success seen in the study by Claude Guérin published in the New England Journal of medicine in 2013. In this trial involving 466 patients, a mortality benefit of over 50 % was seen at 28-days and 90-days.

Prone Positioning Swimmer Crawl

Prone positioning improves lung compliance and ventilation-perfusion matching by reducing the posterior atelectatic lung. This is because the heart and anterior lung fields are placed down, instead of acting with gravity to compress the larger posterior lungs. Therefore, more of the lung parenchyma is ventilated, and at a fixed tidal volume the lung will suffer less barotrauma.

Placing a patient in the prone position requires significant effort and has serious risks. Close attention to lines, drains, and airway is critical, as is obsessive attention to pressure point padding and prevention of ulcers. Because of the “unnatural ICU position”, and the risks involved, ICU staff (physicians, nurses, respiratory therapists) have a natural reluctance for prone positioning despite its potential benefits.

Pre-Prone Planning

Should be considered a procedure, with planning, consent, and timeout. Since prone positioning is usually considered are ventilator optimization, inhaled prostacyclins, deep sedation and neuromuscular blockade have already been done, the patient is often has poor oxygenation, and tenuous respiratory and cardiovascular condition. Given the risks, careful planning and preparations are critical.

  • Identify physician to authorize and supervise procedure (attending or fellow).
  • Order for prone positioning should be entered into the patient’s chart.
  • Review inclusion & contraindications.
  • Discuss risk/benefits of the procedure with the patient’s decision maker.
  • A central venous catheter, arterial catheter, urethral catheter, and feeding tube should be placed before proning.
  • Gather staff that will be available for the 15-20 minutes to perform the proning. This usually involves 3-4 nurses, physician, and respiratory therapist.

Gather Equipment Required for Proning

  • Pillows (3-4).
  • Flat sheets (2).
  • Dry flow pads (2-3).
  • ECG leads/patches.
  • ETT holder (twill tape, E-tab, etc).
  • Extra ventilator circuit including suction catheter.
  • Doughnut pillow for head.
  • Ensure oral suction and ETT suction available (either inline or catheter).
  • Have emergency airway cart and appropriate sized ETT immediately available.
  • Consider ordering speciality bed.

Pre-Proning Preparation

  • Verify ETT is well secured.
  • Optimize ventilator settings and pre-oxygenate patient. Place patient on FiO2 100% during turn.
  • Suction ETT and oral cavity.
  • Remove and cap unnecessary lines tubes (eg, blood pressure cough, CVP monitoring, tube feedings, maintenance fluids).
  • Clean patient.
  • Perform any necessary wound care and change dressings.
  • Ensure patient is well sedated, with adequate analgesia and neuromuscular blockade.
  • Remove ECG patches and leads from limbs and anterior chest.

The Turn Checklist

  1. MD in room.
  2. Identify turn leader (usually the patient’s primary nurse).
  3. Respiratory therapist at head of bed. Responsible for ETT
  4. Minimum 2 staff each side of bed.
  5. Tuck arm under patient (arm closest to the ventilator)
  6. Place oximeter probe on limb not being turned under patient.
  7. Place two pillows on patient’s chest.
  8. Place flat sheet on top of pillows/patient.
  9. Slide patient to edge of bed (away from ventilator)
  10. Check ETT, lines, tubes.
  11. Rotate patient and slowly turn toward vent until in prone position.
  12. Check ETT, lines, tubes. Assess lines and tubes for dislodgement/kinks/air entry
  13. Position arms in modified swimmers crawl. Face is in the direction of the raised arm. Shoulder dropped and elbow below axilla and other arm at side, palm facing up (see figure above).
  14. Ensure pillows are under shins and toes are off the bed.
  15. Reattach disconnect lines/cables.
  16. Place bed in reverse Trendelenburg.
  17. Reassess ETT cuff pressures, tidal volumes, sats, BP, HR.

I recommend that initial proning be performed manually a regular patient bed to monitor the response. We have been maintaining the patient in the prone position 16 hours/day and placed in the supine position for 8 hours per day assuming the patient can tolerate it. If it appears that the patient is going to require ongoing proning, there is benefit from safety and staff resources to using a speciality rotating bed.

Prone Positioning Tips and Checklist

ECMO Flow Sensor Coupling Paste

Resus Review

Knowledge of the blood flow in the ECMO circuit is critical for managing the patient safely. If the circuit is driven by a positive displacement pump, the blood flow rates are determined solely by the pump. However, with centrifugal flow pumps, the flow rate is dependent not only on the pump rotational speed, but also upstream and downstream pressures. In this case, ultrasonic flow transducers provide are able accurate measurements on circuit blood flow.

With the Maquet ROTAFLOW Centrifugal Pump, the flow sensor is located on the downstream side of the pump. It clamps over the circuit tubing going to the oxygenator.

ECMO Pump Ultrasonic Flow Sensor

The ECMO ultrasound flow sensors require a conductive interface between the sensor and the circuit. This is usually a gel or paste. Important properties for the include:

  • Highly conductive at frequencies used by the flow sensor
  • Non-marring
  • Does not dry out
  • Easy to remove
  • Non toxic

The most popular ultrasound gel found in emergency departments and intensive care units is Parker Labs Aquasonic. It is made of a combinations of propylene glycol, glycerine, perfume, dyes, phenoxyethanol or carbopol R 940 polymer along with lots of water. While it is useful to use for ultrasound exams, when exposed to air it dries out quickly which interferes with the flow sensor operation.

Aquasonic Ultrasound Gel

A better product to use is Em-tec Ultrasonic Coupling Paste. It is designed specifically for flow sensors. It remains pliable and does not dry out when exposed to air. This allows accurate performance of the flow sensor for weeks.

Ultrasonic Coupling Paste

ECMO Flow Sensor Coupling Paste

Dantrolene for Malignant Hyperthermia

Resus Review

Malignant hyperthermia is a life-threatening reaction to volatile anesthetics and the neuromuscular blocking agent succinylcholine. A genetic mutation in the ryanodine receptor causes sequestration of intracellular calcium and rigid muscle contractions, which requires large quantities of ATP which is is replenished by uncontrolled oxidative metabolism. The result is heat production and high body temperatures.

Dantrolene acts at the ryanodine receptor blocking the release of calcium from the sarcoplasmic reticulum, and reducing the intracellular calcium, thereby countering the effects of the malignant hyperthermia. Although, Dantrolene does not block neuromuscular transmission nor interfere with reversal of muscle relaxants, the mechanical response to nerve stimulation will be depressed.

Dantrolene Administration IV

The recommended starting dose is 2.5 mg/kg intravenously based upon the patient’s true weight rather than ideal weight, although no scientific study has addressed the difference in this dosing recommendation. Following the initial dose administration, if symptoms are not improving, continuing to administer up to 10 mg/kg is also recommended.

Dantrolene is provided as a powder and is prepared by mixing with sterile water. Sterile phlebitis may follow administration of dantrolene, and should be infused through the largest possible vein. When used with calcium channel blockers (verapamil or diltiazem), dantrolene may produce life-threatening hyperkalemia and myocardial depression. Once a patient has been successfully treated for 48 hours with intravenous dantrolene may be stopped.

Dantrolene for Malignant Hyperthermia