Anesthesia Patient Safety Podcast

#218 Unmasking the Risks: The Dangers of Low Blood Pressure During Surgery

• Anesthesia Patient Safety Foundation • Episode 218

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Ever wondered about the dangers of low blood pressure during surgery? This episode features Amy Yerdon, a certified registered nurse anesthetist and assistant professor at the University of Alabama, Birmingham, who brings to light the critical issue of intraoperative hypotension. Alongside co-authors Matt Scherrer and Desiree Chappell, Yerdon underscores the often-overlooked consequences that patients face post-surgery due to intraoperative hypotension, including acute kidney injury, myocardial injury, and even mortality. This discussion is a must-listen for anesthesia professionals dedicated to improving perioperative patient safety.

Tune in to understand how monitoring and managing blood pressure can significantly reduce postoperative complications and healthcare costs. We discuss the alarming gaps in knowledge among anesthesia professionals, largely due to insufficient postoperative reporting. This episode is packed with invaluable insights that could shape the future of anesthesia care and patient outcomes. Don't miss this crucial conversation on how proactive measures can prevent future harm by working to decrease and prevent intraoperative hypotension.

For show notes & transcript, visit our episode page at apsf.org: https://www.apsf.org/podcast/218-unmasking-the-risks-the-dangers-of-low-blood-pressure-during-surgery/

© 2024, The Anesthesia Patient Safety Foundation

Speaker 1:

You're listening to the Anesthesia Patient Safety Podcast, the official podcast of the Anesthesia Patient Safety Foundation. We're bringing you the very best from the APSF newsletter and website, as well as the latest information in perioperative patient safety. Thanks for joining us.

Speaker 2:

Hello and welcome back to the Anesthesia Patient Safety Podcast. My name is Allie Bechtel and I'm your host. Thank you for joining us for another show. Let's open the June 2024 APSF newsletter. Once again, we have an important public safety announcement for you today. Before we dive into the episode, we'd like to recognize BD, a major corporate supporter of APSF. Bd has generously provided unrestricted support to further our vision that no one shall be harmed by anesthesia care. Thank you, bd. We wouldn't be able to do all that we do without you. Our featured article today is Interoperative Hypotension a public safety announcement for anesthesia professionals by Amy Yurden, matt Scherer and Desiree Chappell. To follow along with us, head over to apsforg and click on the newsletter heading First. One down is the current issue. Then scroll down until you get to our featured article today. I will include a link in the show notes as well To help kick off the show. Today we are going to hear from one of the authors.

Speaker 3:

Let's take a listen now, hi my name is Amy Yurden and I am a certified registered nurse anesthetist. I'm also an assistant professor and the assistant program director of the nurse anesthesia program at the University of Alabama in Birmingham in the United States, and I also work clinically at Huntsville Hospital in Huntsville, alabama.

Speaker 2:

I asked Fjorden why she wrote this article. Here is her response.

Speaker 3:

My co-authors, matt Scherer and Desiree Chappell, and I believe that there's an urgent need to raise awareness for all anesthesia professionals on this important issue. We wrote this review article to highlight the associations between intraoperative hemodynamic management, or potential mismanagement, and patient morbidity and mortality. There's a lack of reporting postoperative patient outcomes to frontline anesthesia professionals, which further complicates the potential knowledge gap. Without up-to-date education or post-op data, many anesthesia professionals do not believe their patients ever experience any adverse effects of their anesthetic care. When talking with colleagues about this issue, I often hear them say I've never had a patient experience any post-op issues because of hypotension. We felt it was time to sound the alarm on this important patient safety issue. As one of the most read journals by all types of anesthesia professionals, we felt the APSF newsletter was the best place to publish this article to impact the most patients by reaching the most anesthesia professionals.

Speaker 2:

Thank you so much to Yurden for helping to introduce this important article and topic. Let's get into the article now. Let's get into the article now. Interoperative hypotension is a big threat to anesthesia patient safety. Interoperative hypotension is associated with a variety of postoperative outcomes, including acute kidney injury, myocardial injury after non-cardiac surgery and mortality. There may also be associations between intraoperative hypotension and delirium, stroke and hospital readmissions. There are significant risks associated with low blood pressures in the operating room, and this is something that anesthesia professionals may be able to do something about. To help keep patients safe, monitoring blood pressure is required during anesthesia care, and blood pressure management is part of the job for anesthesia professionals, and it is a very important part of the job, since intraoperative hypotension may have significant adverse effects even after the patient leaves the operating room. There is evidence to support the association between intraoperative hypotension and acute kidney injury, myocardial injury after non-cardiac surgery and mortality, as well as delirium, stroke and hospital readmissions. These adverse outcomes may continue to have a big impact on patient safety during the postoperative period. For example, patients who develop acute kidney injury are at risk for additional complications, including stroke, myocardial injury, chronic kidney disease, in-hospital mortality and one-year mortality. Acute kidney injury may also involve increases in hospital length of stay, healthcare resource utilization and healthcare costs. Anesthesia professionals may not be aware of the downstream effects from intraoperative hypotension once the patient leaves the recovery room, and this is an important area where anesthesia professionals can work to decrease intraoperative hypotension to then avoid future harm and keep patients safe. Let's start with some definitions. Interoperative hypotension occurs when the blood pressure drops below a safe threshold, leading to end-organ hypoperfusion. When evaluating the incidence of interoperative hypotension, it depends on the reduction of blood pressure and the duration of the reduction. First, we are going to look at the study by Salmasi and colleagues published in Anesthesiology in 2017, relationship Between Interoperative Hypotension Defined by Either Reduction from Baseline or Absolute Thresholds, and Acute Kidney Injury and Myocardial Injury After Non-Cardcardiac surgery a retrospective cohort analysis. Check out the show notes for the citation. This study used a 20% reduction from preoperative baseline blood pressure and an absolute threshold to define intraoperative hypotension. The authors discovered that using the relative threshold or the absolute threshold had a similar ability to differentiate between patients with myocardial and kidney injury and those without. Thus, it may be possible to use an absolute threshold to determine intraoperative hypotension. The results from the study revealed that mean arterial blood pressure less than 65 mmHg for one minute was associated with an increased risk of acute kidney injury and myocardial injury. The risk increased as the duration of the hypotension increased as well, increased as the duration of the hypotension increased as well.

Speaker 2:

Following this study, interoperative hypotension was defined as mean arterial blood pressure less than 65 mmHg for at least 1 minute. Now, if we scan the literature on interoperative hypotension between the first definition in 2017 until 2022, we can see that the most common definitions include the following any map less than 65, or any map less than 65 for at least one minute. With these definitions, it becomes clear that this is a very common event. How common? Well, if we look at a recent retrospective observational multicenter study of over 22,000 patients by Shaw and colleagues, over 88% of non-cardiac surgery patients had at least one episode of intraoperative hypotension for greater than or equal to one minute, and 33% of patients for at least 10 minutes. The mean duration of the hypotensive events was found to be about 28 minutes. Check out table 1 in the article for a comparison of the different incidences of intraoperative hypotension with mean arterial blood pressure less than 65 reported in the literature. In these studies of thousands of patients, the incidence of intraoperative hypotension ranged from 19.3% to 88%. Ranged from 19.3% to 88% and the mean duration of intraoperative hypotension was between 22 and 36 minutes.

Speaker 2:

What about in your practice? Do you see intraoperative mean arterial blood pressure values of less than 65 when you are providing anesthesia care? When you are providing anesthesia care, interoperative hypotension is getting more attention and is recognized as a new quality measure by the Centers for Medicare and Medicaid Services. Map. Less than 65 millimeters of mercury for greater than 15 minutes is a new criterion in the Merit-Based Incentive Payment System, or MIPS. The Merit-Based Incentive Payment System. Total score depends on quality, cost, promoting, interoperability and improvement activities. For this specific measure, a lower interoperative hypotension score means that the patient spent less time with a mean arterial blood pressure less than 65. This is one of six different anesthesia measures that may be submitted for the quality part of the MIPS score and the final MIPS score is used to determine payment adjustments for Medicare Part B claims. Adjustments for Medicare Part B claims.

Speaker 2:

Using this quality measure, we can continue to evaluate the incidence of interoperative hypotension. Let's check out the 2023 article Incidence of Interoperative Hypotension During Non-Cardiac Surgery in Community Anesthesia Practice a Retrospective Observational Analysis. I will include the citation in the show notes as well. In this study, the incidence of hypotension was found to be 29% during non-cardiac procedures and there was varying incidence among clinicians, which signifies practice variation. This is an area where, if we can reduce practice variation with quality improvement initiatives, we hope to improve interoperative hypotension management and reduce the incidence of this modifiable risk. If we continue to look into the threat of interoperative hypotension, we see that more severe hypotensive events and longer duration was associated with increased risk for morbidity and mortality. Keep in mind that MAP less than 65 for longer periods of time, or any MAP less than or equal to 55 is associated with an increased risk for adverse postoperative outcomes.

Speaker 2:

Anesthesia professionals are charged with minimizing the occurrence, severity and duration of intraoperative hypotension as part of every anesthesia plan. An important step for keeping patients safe involves careful blood pressure monitoring. We often use non-invasive intermittent oscillometric blood pressure monitoring with an arm cuff. However, this type of blood pressure monitoring may lead to delayed or missed detection of blood pressure changes or hypotensive events, inaccurate measurements with extremes of blood pressure and overestimation of blood pressure during hypotension, leading to more severe hypotensive events than what is recognized by the anesthesia professional. We may even be missing hypotensive events with non-invasive blood pressure cuff measurements, depending on the frequency of the monitoring and the default settings of the monitor. The most common frequencies for this monitoring are every 2-5 minutes. Without constant monitoring, there may be a longer duration of hypotension or a period of time when hypotension remains undetected, which increases the threat to patient safety. There are several benefits for continuous blood pressure monitoring, including the following Less blood pressure variability, improved hemodynamic stability, detection of hypotensive events that are missed by intermittent blood pressure monitoring, earlier recognition and treatment of intraoperative hypotension and an overall reduction of intraoperative hypotension.

Speaker 2:

Continuous blood pressure monitoring may be done with invasive intra-arterial blood pressure monitoring. The risks for this procedure include infection, nerve damage, thrombus and pseudoaneurysm. Non-invasive continuous blood pressure monitoring may be done with a finger cuff, which avoids the risks of an invasive procedure but is limited by the additional cost of this technology compared to a blood pressure cuff and the potential for less accuracy in older patients and those with atherosclerosis. Do you have a non-invasive finger cuff available at your institution? This device uses volume clamp technology using varying cuff pressure over the finger arteries to maintain constant volume. Then the finger arterial blood pressure is reconstructed into an arterial waveform, which can then be used for pulse wave analysis and the resultant advanced hemodynamic variables of stroke volume, cardiac output and stroke volume variation. These variables may be able to help determine the cause of the hypotension so that you can then provide the necessary treatment. Cause of the hypotension, so that you can then provide the necessary treatment. This is an excellent monitoring choice when you want a continuous blood pressure monitor but you do not need to collect samples of arterial blood during the surgical procedure.

Speaker 2:

We have made it to the end of the show, but not the end of the article. We hope that you tune in next week as we continue the conversation about intraoperative hypotension and the threat to anesthesia patient safety. The big takeaway for today is the following Clinicians should minimize the occurrence, severity and duration of intraoperative hypotension. We hope that you will make this your new mantra and incorporate it into your anesthesia practice to help keep patients safe. If you have any questions or comments from today's show, please email us at podcast at apsforg. 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 apsforg for detailed information and check out the show notes for links to all the topics we discussed today.

Speaker 2:

It has been a couple of months since the last APSF newsletter was published and we are eagerly awaiting the next release in October. In the meantime, we hope that you will check out the articles between issues over on our website. Recent articles include can we apply the lessons we have learned or not from our recent pandemic to mass casualty readiness, perioperative handoff, education resources and case report. Needle thoracostomy the right equipment for the job. So what are you waiting for? Check out the link in the show notes or head over to apsforg and click on the newsletter heading. Second one down is articles between issues. Until next time, stay vigilant so that no one shall be harmed by anesthesia care.