Episode #148 Liver Transplantation Anesthesia: Blood Transfusions and Hemodialysis

Hello and welcome back to the Anesthesia Patient Safety Podcast.  My name is Alli Bechtel, and I am your host. Thank you for joining us for another show. Last week, we talked about providing anesthesia care for patients for one of the most challenging cases in the operating rooms with frequent hemodynamic changes, the possibility for massive blood loss and coagulopathy in sick patients and often takes place in the middle of the night. Today, we are continuing the conversation about keeping patients safe during anesthesia care for liver transplantation.

Before we dive into the episode today, we’d like to recognize Medtronic, a major corporate supporter of APSF. Medtronic has generously provided unrestricted support to further our vision that “no one shall be harmed by anesthesia care”. Thank you, Medtronic – we wouldn’t be able to do all that we do without you!”

Our featured article is once again “Evolving Safety Challenges in Patients Presenting for Liver Transplantation Today: A Single-Center Experience” by Tran, Sedra, and Szokol. To follow along with us, head over to APSF.org and click on the Newsletter heading. First one down is the current issue. From here, scroll down until you get to our featured article today. I will include a link in the show notes as well.

We are heading back into the main operating room to talk about one of the most challenging cases, liver transplant. So, go ahead and refresh your cup of coffee or tea because here we go!

Last week, we talked about calculating the MELD score and the associated 3-month mortality. We also talked about some of the threats to anesthesia patient safety during liver transplant today since patients are more likely to present with the following characteristics:

• Higher MELD scores
• Advanced liver disease
• Older age
• More significant preoperative comorbidities
• More renal and electrolyte abnormalities
• Increased transfusion and vasopressor requirements during surgery

Plus, it is important to have a designated liver transplant anesthesia team to help keep patients safe and this is associated with reductions in the following:

• Transfusions
• time of postoperative ventilation
• length of stay in the intensive care unit
• perioperative mortality

Last week, we introduced the process of blood management during liver transplantation and talked about the importance of minimizing blood transfusions to help keep patients safe. Let’s pick up right where we left off.

Remember, increased blood transfusions area associated with increased length of hospital stay as well as higher rates of infection, graft failure, and mortality. This is a threat to patient safety. The evidence that supports a more restrictive transfusion strategy is newer, in the past 10 years and ongoing. The authors describe the preliminary data from a retrospective study being conducted when this article was written. The preliminary data results are:

20% decrease in RBCs, platelets, and plasma administered during liver transplant cases in 2021

This was compared to 2020 and there were more cases performed in 2021.

So, how was this significant reduction accomplished?

The interventions included the following:

First, a hospital-wide campaign to educate and promote a change in the culture away from liberal blood utilization practice which included the slogan, “Why give 2 when 1 will do?” which is quite catchy and helped to support a choosing wisely campaign to reduce orders for automatic multi-unit RBC transfusions.

Next, there was the implementation of intraoperative thromboelastography or TEG. Intraoperative TEG may have only become recently available in an operating theatre near you, but viscoelastic tests were first used to evaluate hemostatic control in liver transplantation by Thomas Starzl who performed the first one in the 1960s. Over time viscoelastic tests have been used in clinical practice, but recent technological advances and further clinical trials have further increased the availability and use. The author’s report that the use of TEG in the operating rooms and ICU was expedient and efficient and provided rapid, real-time, qualitative assessment of various components of hemostasis and can be used to guide appropriate transfusions when necessary. Another important step for appropriate blood management is the communication between the liver anesthesia and surgical teams. This communication may include a discussion about surgical bleeding as well as the results from the TEG in order to guide and likely reduce intraoperative transfusions. There is a call to action for multidisciplinary teams to work together to significantly decrease blood and blood product transfusions during liver transplantation.

Next up, we are going to talk about intraoperative hemodialysis during liver transplantation. This is important since patients with renal dysfunction are at risk for significant fluid shifts, acidosis, and electrolyte and coagulation abnormalities that may need to be treated with large volumes of blood products and crystalloid solutions. Have you provided anesthesia care for a patient with renal dysfunction or renal failure undergoing liver transplant surgery without intraoperative hemodialysis? The anesthesia care likely required strict fluid management and a close eye on the electrolytes and acid-base status, but even then it may have been complicated by significant fluid and metabolic changes. Enter intraoperative renal replacement therapy for patients with renal failure undergoing liver transplant to help with the major hemodynamic instability, coagulation abnormalities, and metabolic derangements. The author’s discuss the use of intraoperative hemodialysis during liver transplant since their institution was the first to demonstrate the safety and feasibility of intraoperative hemodialysis for critically ill patients with MELD greater than 37 during liver transplantation.

In clinical practice, deciding to use intraoperative HD requires input from the surgeon, anesthesia team, and nephrologist, depends on the degree of renal dysfunction, and depends on the patient’s need for postoperative renal replacement therapy. Here are some considerations for intraoperative hemodialysis:

Patients will likely have glomerular filtration rate less than 60ml/min or Serum creatinine greater than 1.4mg/dL.

If there is no permanent dialysis access, a dual-lumen HD catheter may be placed in the internal jugular, subclavian, or femoral vein.

Before the surgery, the nephrologist must decide on the concentration of sodium, calcium, potassium, and bicarbonate in the dialysate solution for each patient depending on their preoperative laboratory values.

During the operation, the HD nurse works with the anesthesia team

Frequent arterial blood gas assessments, every 30-60 minutes, are used to guide changes in the dialysate throughout the surgery with particular attention to the bicarbonate and potassium levels.

There are many benefits for using intraoperative hemodialysis including management of the following:

• Temperature
• Acidosis
• Hyperkalemia
• Volume overload

Check out Table 2 in the article for an overview of treatment variations that are available during intraoperative HD. We are going to review it now.

First up, temperature:

• Dialysate temperature is kept between 37-37.5 degrees Celsius
• Aids in prevention of hypothermia-related coagulopathy and cold irrigation from graft

Next up, sodium adjustments which includes routinely started at 138mEq/L which may be adjusted between 130-138 mEq/L. Careful monitoring is necessary to prevent rapid rise in serum sodium concentrations associated with CPM or Central Pontine Myelinosis.

Calcium adjustments may be made as well. Levels are started at 3.5mEq/L and may be adjusted between 3-3.5mEq/L. This is important to help manage hypocalcemia during massive blood transfusion.

Let’s talk about the potassium and bicarbonate adjustments next. It is routine to start with a dialysate with a potassium level of 3mEq/L which may be adjusted between 1-4 mEq/L to help with the management of hyperkalemia during massive blood transfusion and pre-existing renal dysfunction. For bicarbonate, the levels usually start with a dialysate level of 35mEq/L which may be adjusted between 25-35 mEq/L to help with the treatment of refractory acidosis that may occur in patients with renal dysfunction especially during the anhepatic phase. Finally, let’s talk about ultrafiltration flow rates which may be managed with a goal to maintain an even fluid balance, but this may change depending on consultation with the anesthesia team. For example, ultrafiltration flow rates may be increased to treat volume overload with rapid volume removal. This may be necessary if there is right heart strain post-reperfusion or graft congestion.

The authors advocate for intraoperative HD to help keep patients with high MELD scores and renal dysfunction safe during liver transplantation with considerations for preoperative evaluation, appropriate monitoring, and continuous interventions with input from a multidisciplinary team.

For all liver transplant anesthesia professionals and any members of the multidisciplinary team who help to take care of liver transplant patients, there is a call to action to recognize the increasing complexity of patients presenting for liver transplant and meet the challenges to help keep these critically ill patients safe. Going forward to improve perioperative patient safety for liver transplant patients, more comprehensive data and studies are needed to characterize the evolving safety challenges in liver transplantation today.

If you have any questions or comments from today’s show, please email us at [email protected]. Please keep in mind that the information in this show is provided for informational purposes only and does not constitute medical or legal advice. We hope that you will visit APSF.org for detailed information and check out the show notes for links to all the topics we discussed today.

Have you checked out the Conferences and Events heading over at APSF.org? What are you waiting for? You can scroll down and check out the Upcoming events featuring the APSF. Then, you can see that in just a couple days there is an Anaesthesia Patient Safety Symposium Pre-conference Event on May 6, 2023 with a focus on technology and anesthesia patient safety. Some of the featured talks will discuss the pulse oximeter, training for advanced anesthesia technology, alarm fatigue, and personal electronic devices. You don’t want to miss it! Then, on May 20-21, there is the Anaesthesia Patient Safety Symposium 2023 focused on Advancing Anesthesia Patient Safety Together. Registrations are open now for this virtual event. This meeting will bring together global and local leaders and practitioners who are all committed to improving patient safety. The registration fee includes attendance to all live sessions from 20-21 May and access to video on demand after the symposium. Plus, you can let us know you are attending by tagging us on twitter @APSForg. We would love to hear from you.

Until next time, stay vigilant so that no one shall be harmed by anesthesia care.

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