The St.Emlyn’s Podcast

Back in late 2018 we gathered in Manchester for the inaugural #stemlynsLIVE conference. Our friend Dr George Wills gave a great talk on Aortic Emergencies.

All emergency physicians know that it's all to easy to miss an aortic catastrophe. Listen to George's wisdom on common pitfalls and top tips to make you a better emergency clinician.

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Also check out these excellent #FOAMed resources.

• Subscribe to the blog (look top right for the link)

Back in late 2018 we gathered in Manchester for the inaugural #stemlynsLIVE conference. Our friend Dr George Wills gave a great talk on Aortic Emergencies.

All emergency physicians know that it's all to easy to miss an aortic catastrophe. Listen to George's wisdom on common pitfalls and top tips to make you a better emergency clinician.

vb

S

Also check out these excellent #FOAMed resources.

• Subscribe to the blog (look top right for the link)

Last year we were honoured to bring Kat Evans to Manchester to talk at the #stemlynsLIVE conference. We've covered emergency medicine in South Africa before on the blog, but there is no substitute to hearing about it from someone who actually works there.

Last year we were honoured to bring Kat Evans to Manchester to talk at the #stemlynsLIVE conference. We've covered emergency medicine in South Africa before on the blog, but there is no substitute to hearing about it from someone who actually works there.

Welcome to St Emlyn's blog, where we delve into the complex world of P values—a crucial element in medical research. For emergency medicine clinicians, understanding P values is essential for interpreting study results and applying them effectively in clinical practice. This post aims to demystify P values and enhance your critical appraisal skills.

P values are a measure of the probability that an observed difference could have occurred just by chance if the null hypothesis were true. The null hypothesis generally states that there is no difference between two treatments or interventions. Thus, a P value helps us determine whether the observed data is consistent with this hypothesis.

To grasp P values fully, we start with the null hypothesis. In any trial, we begin with the premise that there is no difference between the treatments being tested. Our goal is to test this null hypothesis and ideally disprove it, a process known as significance testing.

When we calculate a P value, we express the probability of obtaining a result as extreme as the one observed, assuming the null hypothesis is true. For instance, a P value of 0.05 suggests a 5% chance that the observed difference is due to random variation alone.

The threshold of 0.05 has become a benchmark in research. A P value below this threshold is often considered statistically significant, while one above is not. However, this binary approach oversimplifies statistical analysis. The figure 0.05 is arbitrary and does not imply that results just above or below this threshold are vastly different in terms of practical significance.

Distinguishing between statistical significance and clinical significance is crucial. A statistically significant result with a very small P value may not always translate into clinical importance. For example, a large study might find that a new treatment reduces blood pressure by 0.5 millimetres of mercury with a P value of 0.001. While statistically significant, such a small reduction may not be clinically relevant.

Conversely, a clinically significant finding might not reach the strict threshold of statistical significance, particularly in smaller studies. Therefore, it's essential to consider both the magnitude of the effect and its practical implications in clinical practice.

The fragility index is an alternative measure that addresses some limitations of P values. It calculates the number of events that would need to change to alter the study's results from statistically significant to non-significant. This index provides insight into the robustness of the findings. Surprisingly, even large trials can have a low fragility index, indicating that their results hinge on a small number of events.

Recognizing the limitations of the 0.05 threshold, some researchers advocate for more stringent criteria, such as a P value of 0.02, particularly in large randomized controlled trials (RCTs). This approach aims to reduce the likelihood of false-positive results and improve the reliability of findings. However, it also raises the bar for demonstrating the efficacy of new treatments, which can be a double-edged sword.

A significant challenge in research is multiple testing. Conducting numerous statistical tests increases the probability of finding at least one significant result purely by chance. This issue is particularly relevant in exploratory studies where multiple outcomes are assessed.

One method to address this problem is the Bonferroni adjustment, which adjusts the significance threshold based on the number of tests performed. While this approach helps control the risk of false positives, it can be overly conservative and reduce the power to detect true effects. Therefore, it should be used judiciously.

Interim analysis is a crucial aspect of clinical trials, allowing researchers to assess the effectiveness or harm of an intervention before the study's completion. However, performing multiple interim analyses can increase the risk of false-positive findings. To mitigate this risk, researchers use techniques like P value spending functions, which adjust the significance threshold for each interim analysis.

Additionally, the number of interim analyses should be limited and pre-specified in the study protocol. This ensures that decisions to stop a trial early are based on robust evidence and not on arbitrary or opportunistic analyses.

P values alone do not provide a complete picture of the study results. It's equally important to consider the effect size, which measures the magnitude of the difference between treatments. A small P value might indicate statistical significance, but without a substantial effect size, the clinical relevance of the finding remains questionable.

Confidence intervals (CIs) complement P values by providing a range within which the true effect size is likely to lie. A 95% CI means that if the study were repeated multiple times, 95% of the calculated intervals would contain the true effect size. CIs offer valuable context for interpreting P values and understanding the precision of the estimated effect.

1. Understand the Null Hypothesis: Always start with a clear understanding of the null hypothesis and what the study aims to test.

P values are a fundamental aspect of medical research, but their interpretation requires a nuanced understanding. By considering the null hypothesis, clinical significance, effect size, and confidence intervals, we can make more informed decisions based on the data. As emergency medicine clinicians, our goal is to apply research findings judiciously to improve patient care.

We hope this deep dive into P values has clarified their role and limitations in research. Remember, the journey to mastering statistical concepts is ongoing, and continuous learning is key. If you have any questions or thoughts, please share them in the comments below. Happy appraising, and stay curious!

St. Emlyn's January Roundup: Key Insights and Innovations

Hello and welcome to the St. Emlyn’s Podcast. I’m Simon Carley, joined by Rick Body. Today, we’re bringing you our January roundup, sharing the most intriguing and impactful content we've covered this month. From reflecting on 2018 to exploring new guidelines and innovations in emergency medicine, we have a lot to discuss. Let’s dive in!

As we started January, we reflected on 2018, a year filled with significant achievements and insights. One standout discussion was our review of key books that left a lasting impact. A personal favorite of mine is "Why We Sleep" by Matthew Walker. This book has been transformational for me, influencing how I live and advise others on health, well-being, and performance. The insights on sleep’s importance in education, creativity, and overall health are profound.

Rick, did anything from our 2018 review resonate with you?

Rick Body: Absolutely, Simon. The variety of books we discussed was impressive. It was enlightening to hear about others' achievements in 2018 and their goals for 2019. This exercise really focused my mind on what I hope to achieve this year.

As we moved from reflections to aspirations, we set our sights on exciting projects for 2019. One major highlight is the AI incubator for emergency care. This initiative aims to support academic careers and foster partnerships between data and industry to enhance medical technologies. It’s an exhilarating time for advancements in emergency care.

Rick is incredibly busy with groundbreaking work, particularly in diagnostics in Manchester. His research and speaking engagements are making waves in the medical community. For more details on these projects, check out the blog where all the information is comprehensively covered.

We explored New Year’s resolutions with Liz Crowe, who offered a fresh perspective on well-being and resolutions. Instead of focusing on all-or-nothing goals, Liz suggests starting small and seeking rewards rather than punishments. This approach makes significant lifestyle changes more manageable and sustainable. Committing to resolutions publicly or with a friend can enhance accountability and success.

Rick, do you have any New Year’s resolutions?

Rick Body: It’s challenging to pinpoint one or two, but Liz’s advice on avoiding binary thinking is crucial. Recognizing progress rather than dwelling on setbacks can make a big difference.

In January, we delved into updated tetanus guidelines, highlighting significant changes. Previously, a single booster in your early 20s was deemed sufficient, but the new guidelines recommend a 10-year booster. This change stems from the recognition that immunity wanes over time. Interestingly, point-of-care testing is now available to detect active tetanus immunization, allowing for more tailored booster decisions.

These updates are crucial for emergency physicians to ensure compliance with current standards and provide optimal patient care. The blog post simplifies these guidelines, making them accessible and easy to understand.

We featured Claire Richmond, a hero in the emergency medicine community. Claire, who works with Sydney HEMS, delivered an inspiring keynote at the St. Emlyn’s live conference. Her talk focused on excellence, performance, training, and development in retrieval medicine. She emphasized the importance of honesty, feedback, and continuous improvement.

For those aspiring to achieve self-actualization in emergency medicine, Claire’s insights are invaluable. We’ve shared the video and podcast of her talk, and we highly recommend checking them out.

Another highlight of January was Professor Dan Horner’s discussion on serum neurofilament light chains, a promising tool for prognosticating cardiac arrest outcomes. This research, stemming from the TTM trial, suggests that these biomarkers can provide early predictions about patient outcomes. Early identification of patients likely to have poor neurological outcomes can significantly impact family discussions, treatment decisions, and overall management.

This research is groundbreaking and holds potential for future clinical applications, although it’s not yet ready for immediate practice.

We’re incredibly proud of our journal club series at St. Emlyn’s, which advocates for evidence-based medicine. This series highlights the latest research, making it accessible and understandable. To celebrate the contributions over the past year, we’ve compiled an e-book available for free download. This resource is a testament to our commitment to advancing medical knowledge and practice.

One of the intriguing studies we covered this month examined pre-medication with midazolam or haloperidol for ketamine sedation. The randomized control trial suggested that pre-medication could reduce complications like abnormal behaviors and emergence phenomena. However, it also increased recovery time, requiring more resources and nursing time.

While the findings are interesting, they haven’t convinced us to change our current practice. However, it’s essential to stay informed about such research to make informed decisions in clinical practice.

We also discussed the role of HEMS in improving outcomes for traumatic cardiac arrest. The study from the UK highlighted the high-level interventions provided by HEMS teams. However, it raised questions about the overall impact on patient survival. Of the 263 patients attended, only seven survived, and all had achieved ROSC before HEMS arrival. This data suggests that while HEMS interventions are critical, their direct impact on survival needs further evaluation.

This topic is sure to spark debate, and we appreciate the transparency of HEMS services in sharing their data and encouraging open discussions.

As we wrap up January, we’re excited about the plans for the coming months. Simon is heading to Jeddah for a significant event, and we’re considering hosting another St. Emlyn’s live conference and teaching course. We’re exploring innovative formats for medical conferences and welcome your ideas on how we can make these events even more impactful.

Since 2012, we’ve funded the blog and podcast out of our own pockets, but as our audience has grown, so have the costs. If you find our content valuable, please consider making a small donation or subscribing for regular contributions. Your support helps us keep St. Emlyn’s free and accessible to all.

Thank you for your time and continued support. Stay tuned for more updates, and as always, enjoy your emergency medicine practice and take care!

In this episode of the St. Emlyn's podcast, Rick Body and Charlie Reynard discuss an influential research project conducted by Dr. Reynard during his academic foundation program. The paper, titled 'Optimizing Antiplatelet Utilization in the Acute Care Setting,' explores decision-making under clinical uncertainty, specifically in emergency medicine for suspected acute coronary syndromes (ACS). Through systematic reviews and decision tree modeling, the research evaluates the benefits and risks of various antiplatelet therapies, such as Ticagrelor and aspirin versus Clopidogrel and aspirin. The findings reveal that Ticagrelor and aspirin are often more beneficial for patients with a greater than 8% probability of ACS, while Clopidogrel holds little to no place in current practice. The discussion opened up new questions about dynamic risk prediction and the importance of modeling to inform clinical decisions.

00:00 Introduction to the Podcast

00:26 Charlie's Research Background

00:52 Overview of the Research Paper

01:17 Decision Making Under Uncertainty

03:05 Systematic Reviews and Data Collection

03:46 Building the Decision Tree Model

04:48 Results and Key Findings

08:07 Implications for Clinical Practice

09:19 Future Directions and Conclusion

In this episode of the St. Emlyn's podcast, Rick Body and Charlie Reynard discuss an influential research project conducted by Dr. Reynard during his academic foundation program. The paper, titled 'Optimizing Antiplatelet Utilization in the Acute Care Setting,' explores decision-making under clinical uncertainty, specifically in emergency medicine for suspected acute coronary syndromes (ACS). Through systematic reviews and decision tree modeling, the research evaluates the benefits and risks of various antiplatelet therapies, such as Ticagrelor and aspirin versus Clopidogrel and aspirin. The findings reveal that Ticagrelor and aspirin are often more beneficial for patients with a greater than 8% probability of ACS, while Clopidogrel holds little to no place in current practice. The discussion opened up new questions about dynamic risk prediction and the importance of modeling to inform clinical decisions.

00:00 Introduction to the Podcast

00:26 Charlie's Research Background

00:52 Overview of the Research Paper

01:17 Decision Making Under Uncertainty

03:05 Systematic Reviews and Data Collection

03:46 Building the Decision Tree Model

04:48 Results and Key Findings

08:07 Implications for Clinical Practice

09:19 Future Directions and Conclusion

This podcast and presentation was recorded at the St Emlyn's LIVE conference in Manchester 2018. In this presentation Clare takes us through the rationale, principles, training and practice that we need in order to continually develop as prehospital and resuscitation practitioners.

You can read more from the event at http://www.stemlynsblog.org 

This is a great presentation for anyone interested in continually developing their own and their colleagues practice, delivered by someone who really knows what they are talking about and who works for one of the best developed resuscitation services in the world.

Clare is an Emergency Physician and specialist in Pre-Hospital Care and Retrieval medicine based in Sydney, with Royal Prince Alfred Hospital and Sydney HEMS. She has completed a fellowship in simulation based education, and enjoys training with “real” people - patients, bystanders and the other clinicians we come across as we treat our patients every day. She is a lecturer with the University of Sydney, and is involved in education for the NSW Institute for Trauma Injury Management. When Clare is not working on helicopters or training teams, she is studying yoga or hanging out with her puppy, Archie. 

This podcast and presentation was recorded at the St Emlyn's LIVE conference in Manchester 2018. In this presentation Clare takes us through the rationale, principles, training and practice that we need in order to continually develop as prehospital and resuscitation practitioners.

You can read more from the event at http://www.stemlynsblog.org 

This is a great presentation for anyone interested in continually developing their own and their colleagues practice, delivered by someone who really knows what they are talking about and who works for one of the best developed resuscitation services in the world.

Clare is an Emergency Physician and specialist in Pre-Hospital Care and Retrieval medicine based in Sydney, with Royal Prince Alfred Hospital and Sydney HEMS. She has completed a fellowship in simulation based education, and enjoys training with “real” people - patients, bystanders and the other clinicians we come across as we treat our patients every day. She is a lecturer with the University of Sydney, and is involved in education for the NSW Institute for Trauma Injury Management. When Clare is not working on helicopters or training teams, she is studying yoga or hanging out with her puppy, Archie.