AKI “Canary in the Coalmine” for Cellular Injury

Surgical backlog discussed in TopMedTalk podcast:

The second of two Deltex-sponsored podcasts is now available on TopMedTalk. The panel turns to efficiency and effectiveness as vital in tackling the weight of post-COVID surgical cases. The subject of Acute Kidney Injury (AKI) avoidance features heavily in the discussion. Indeed the contributors emphasize the importance of maintaining perfusion. In so doing clinicians can optimize outcomes. And while this is always important, it’s never more so than when faced with a huge surgical backlog.

Contributors include Desiree Chappell, Monty Mythen and guest Michael Scott, M.B., Ch.B, Professor of Anesthesiology & Critical Care Medicine at University of Pennsylvania, USA.

Mike Scott is president of the ERAS society. He was formerly UK-based at Royal Surrey, Guildford which boasted some of the best colorectal cancer outcomes in the UK within their ERAS/FastTrack surgery protocol.

Setting the scene, the experts discuss getting patients “in and out” as quickly as possible, with the “least amount of iatrogenic harm.” They also talk of pressure from patients who “don’t want to be in hospital for any longer than necessary.” 

The panel agree that adoption of Enhanced Recovery after Surgery (ERAS) principles is key to reducing the massive surgical backlog that has accumulated during the pandemic. 

Importance of ERAS in AKI avoidance

Professor Scott describes Acute Kidney Injury (AKI) as the “Canary in the coalmine” for cellular injury of anything that is perfused, from the brain to the intestine. Do the best thing for the kidneys and overall outcomes improve, is the message.

AKI can be considered the canary in the coalmine for all tissues that are perfused

Prof Scott goes on to talk of his experience in AKI reduction, specifically his use of hemodynamic therapy. He talks of the principle that everyone undergoing major surgery “deserves” flow-based monitoring, because by definition major surgery is a harm-inducing activity. He claims it’s important to ensure that nobody is overtly hypovolemic if vital organs are to be protected. This means the anesthesiologist must understand the patient’s hemodynamic status and, crucially, be able to track changes. 

The counter-argument from many healthcare providers would be their claim not to face meaningful incidence of AKI. The reality however is that most are not attuned to identifying any other than serious cases. Strikingly, a goal-directed approach to tracking changes in hemodynamic status is supported by evidence. Indeed Prof Scott talked from experience of a reduction in secondary AKI from 14% to 8% in colorectal surgery. More significantly they completely eliminated what he referred to as “bad AKI”.

“Everyone is ultra focused on pressure, which is not the answer”

The panel discussed fluid at length. They agreed that “when to give” is important. In the words of Prof Scott, “timing is absolutely crucial.” (in fact studies on TrueVue EDM+ suggest timing may be more important than ultimate volume, which is often similar in treatment/control groups). 

“Unless you’re measuring flow, you don’t know”

Prof Scott goes on to say that “unless you’re measuring flow, you don’t know” with the caveat that “the problem is that pressure is easy to measure, flow isn’t… otherwise we’d all be doing it” 

“We know from an actuarial point of view that we’re having an enormous impact on downstream outcomes including life expectancy.”

“We’d advise having monitoring on as early as you can. Fill the tank early then maintain during surgery to deliver the required restrictive regime. We need to take an individualizing approach to what we do… there are patient factors and there are surgical factors. You need a roadmap for each of these. In Virginia there exists a hemodynamic framework for each of the specialties, depending on approach, type of surgery and patient factors.”

Key ERAS principles

The group wrapped up by agreeing on the four opportunities for ERAS at a time when surgical capacity is so limited. The things that make the biggest difference are:  

  • What the surgeon does: primary injury and blood loss
  • Reduction of opioids in immediate peri-operative period
  • Goal-Directed Hemodynamic therapy 
  • Patient education and preparation

An unmatched body of clinical evidence backs the use of TrueVue EDM+. Deltex has identified 24 RCTs that relate uniquely to oesophageal Doppler. The link between improving hemodynamic management with reduced AKI and improved outcomes is proven. For example, in the 450 patient FEDORA RCT, post-operative AKI was reduced by 92% when anaesthetists used EDM+. On that basis we should not be surprised to see the subject featuring so prominently in this discussion.

Deltex CEO comments

Commenting on the podcast, Deltex Medical CEO Andy Mears states; “It’s reassuring to see hemodynamic therapy featuring so strongly in the ERAS top four. Evidence we’ve collected and researched over the years has pointed to the importance of flow data, as so uniquely derived using Doppler monitoring. Using pressure as a surrogate, while acceptable to identify fluid changes in stable patients, is clearly inferior in more dynamic settings. That’s what the papers tell us and that’s what this expert panel tells us. We’re most grateful for the opportunity to support this initiative and help to spread the message that ERAS is a vital part of clearing the surgical backlog.”

Find the podcast here

Grateful thanks to Desiree Chappell, Professor Monty Mythen and guest Professor Michael Scott. 

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