Risk Assessment & Mitigation of Perioperative Pulmonary Complications

Raed Dweik, MD:

Hello and welcome to the Respiratory Exchange Podcast. I'm Raed Dweik, Chief of the Integrated Hospital Care Institute at Cleveland Clinic. This podcast series of short digestible episodes is intended for healthcare providers and covers topics related to respiratory health and disease in the areas of lung health, critical illness, sleep, infectious disease, and related disciplines. We will share with you information that will help you take better care of your patients. I hope you enjoy today's episode.

Dan Culver, MD:

Hello and welcome to this edition of Respiratory Exchange. I'm Dan Culver, Chair of Pulmonary Medicine at Cleveland Clinic. Thank you for joining us today. I'm joined by Dr. Preethi Patel today, who's going to speak about something very important and frequent, which is preoperative pulmonary evaluation for risk factors. Dr. Patel is an assistant professor here at Cleveland Clinic Lerner College of Medicine, and she is the associate director of the Center of Perioperative Medicine. Preethi, welcome.

Preethi Patel, MD:

Thank you so much for having me here.

Dan Culver, MD:

Well, this is something that all of us encounter pretty regularly in our clinical practices. And of course, many patients who are undergoing surgery have concerns for pulmonary issues. And so, this is a good chance to review your perspectives on it and maybe some of the later advances.

Preethi Patel, MD:

Yeah, absolutely.

Dan Culver, MD:

So, let's just start off broadly about what is the overall rationale for getting a perioperative pulmonary evaluation? What's the goal and how do you approach it from a 30,000-foot view?

Preethi Patel, MD:

So surprisingly, pulmonary complications are much, much more common than cardiac complications are. So in a broad context of things, knowing how common it is, I think it becomes important for us to check every patient or at least assess them for any sort of preexisting pulmonary condition, any sort of mitigating factors that we may have in the pre-op setting entrap, what we can do to help. Just to put things in context, there are about 150,000 cardiac complications that we record every year. It's a million of pulmonary complications.

Dan Culver, MD:

So, seven times more frequent.

Preethi Patel, MD:

Seven times more frequent. And I think there was a study a long time ago, 1995, that they did a head-to-head study at the VA at about 2,500 patients. So, they saw 9.6% pulmonary complication rate versus five some percent in the cardiac complications rate. And surprisingly, about 28% of them had both. And you know, right if they have cardiac complications, they end up with some sort of pulmonary decompensation as well. So, it's important to talk about that.

Dan Culver, MD:

And when you say pulmonary complications, there's a spectrum of those. What do you mean by that?

Preethi Patel, MD:

So that's another sticky point. There is no specific definition for what constitutes a pulmonary complication as opposed to a cardiac complication, a post-op STEMI, a major cardiac event, a stroke or what have you, heart failure. These are very well defined. However, in the pulmonary realm, anything from post-op hypoxia where you're requiring oxygen for a longer duration than you would use versus ARDS and requiring intubation, reintubation, pneumonias, atelectasis, these are some of the very, very common complications we encounter.

Dan Culver, MD:

When you think about complications, some of them are annoying and might prolong hospitalization, but don't really have residual and aren't very likely to cause mortality and some are of course quite serious. How do you think about the frequency of both of those?

Preethi Patel, MD:

So, that's a very interesting question. So, how does say some patient requiring oxygen postoperatively impact them in the long term? Well, there was one study that came out of, I think, University of Colorado. There were eight academic large tertiary centers that they looked at. Again, about 2,500 patients and even the smallest pulmonary complication had an increased 30-day mortality rate for those patients. So, when you think about it that way, especially in the scheme of things, the numbers are so large, maybe the absolute numbers are not that great, but it's important to talk about it. So, any little complication can cause long-term residual defects.

Dan Culver, MD:

So directly or just as a marker of badness?

Preethi Patel, MD:

Correct.

Dan Culver, MD:

So, you've got to really think about the whole patient. You're thinking about cardiac situation, you're thinking of pulmonary risks, you're thinking about the frailty and the other aspects of the patient's condition before they go into the surgery. But when you think about pulmonary specifically, what are the main components that you're looking at as you start to first walk in the room or start to first review the chart?

Preethi Patel, MD:

So, as opposed to cardiac, the pulmonary risk is highly surgical site specific. So, when I'm looking at a patient who's going to have an upper abdominal surgery like a Whipple or something like that, or even an open cholecystectomy for that matter. So, these are patients who do have the highest pulmonary risk. That's something that's not going to be mitigated. So same thing with cardiothoracic surgery. So, if you're going to be entering the thoracic cavity, you're going to have an increased risk of pulmonary complications. So, if you look at the spectrum of surgical site in the general population, patients going for general surgery, it's about five to six percent. It goes up to 40 to 70% in cardiothoracic surgery patients that the rate of pulmonary complications is that high in those patients. Age is one big thing. We know just the absolute risk of as advanced age is high.

So, patients over the age of 50, patients over the age of 65, they absolutely have an increased risk of pulmonary complications. That's another non-modifiable risk factor we have. Frailty is another thing. Mobility, lack of mobility is something we worry about when it comes to patient risk factors and their underlying COPD, uncontrolled asthma, respiratory infection in the recent past and congestive heart failure. Those are some of the patient risk factors we're looking at. And then like we talked about the surgical risk factors is how long is the surgery going to be. There is very good data that you say surgeries that are less than two hours have a five to six% rate and that goes up to close to 20% once you're under general anesthesia for about four hours or more.

Dan Culver, MD:

And I think you pointed out that there's a difference between open procedures and laparoscopic or endoscopic procedures.

Preethi Patel, MD:

There is a higher risk.

Dan Culver, MD:

And I want to draw you out a little bit on the type of anesthesia. And I know that there are some discussions around general anesthesia, intubation versus non-intubation, spinal anesthesia. Can you elaborate on those a little bit?

Preethi Patel, MD:

So, I'm not an anesthesiologist. I want to put it out there, but we work really very closely with our anesthesiology colleagues and there's very good data to say that higher risk patients, general anesthesia is definitely higher risk for post-op pulmonary complications, bronchospasm that it induces the neuromuscular blockage is one other thing in those patients. So, all those contribute to increasing risk. Neuraxial anesthesia, regional anesthesia, wherever possible, is something that has better outcomes when it comes to post-op pulmonary complications. I saw one study where they say general anesthesia with neuraxial and anesthesia is better than just general itself.

Dan Culver, MD:

Okay. So, it's the type of surgery, it's the underlying patient, it's the anesthesia strategy and you have to synopsize all of those into some sort of estimate for the patient and the surgeon before deciding to go ahead and if there is going to be a surgery, how to mitigate things.

Preethi Patel, MD:

Right.

Dan Culver, MD:

Can you tell me a little bit about what the most common strategies you use are to mitigate risk? Quite often people just want the surgery and so does the surgeon and maybe it's a necessary surgery that's not necessarily elective. So, what are the most common modifiable things that you address in your clinic?

Preethi Patel, MD:

We'll talk about a little bit about the risk tools that we use in the clinic. One thing is we definitely assess everybody for sleep apnea, especially patients with obesity, with history of poor sleep hygiene and stuff like that. So, these patients that come in, everybody we do a stop bank score. It has very good sensitivity, very good negative predictive value to determine especially severe sleep apnea in the pre-op setting. So everybody gets STOP-Bang score. ARISCAT scoring is our tool of choice in our pre-op clinic. For one, it is more broadly with the validation happened and the derivation of the tool. This is from a Spanish registry, and it was much more broad than the older Ozula, which was derived out of the veteran's administration. So, like a huge male population we really couldn't generalize to everybody.

Dan Culver, MD:

And ARISCAT score, just to clarify, really tells you about all postoperative pulmonary complications versus Arozullah, which really focuses more on prolonged ventilation, respiratory failure, correct?

Preethi Patel, MD:

Yes. And you have other newer, the Gupta NSQIP calculators as well, which will tell you only for ARDS and ventilator need and pneumonia. But ARISCAT, like you mentioned, is for pretty much all post-op pulmonary complications and it does put patients in these buckets of low, moderate, and high risk. And there are a lot of modifiable risk factors and non-modifiable risk factors. Some of the modifiable ones that we're looking for is if the patient does have underlying pulmonary disease, is that well controlled or not? If the patient is wheezing actively in our clinic, obviously that's not somebody I would want to send for surgery so that I would optimize their inhaler therapy, maybe send them back to their pulmonologist, maybe give them a short burst of steroids for patients with uncontrolled asthma and COPD before they can go for surgery. Somebody comes in with a lower respiratory tract infection or an upper respiratory tract infection; we rather wait for a couple of weeks before we send them for surgery.

There's one study out of I think 20,000 patients with the flu with lower respiratory infections, and I think their cutoff was two to four weeks after. So, after the flu incidence, the risk of pulmonary complications is really high if we did surgery within that window period.

Dan Culver, MD:

And just to clarify, some of the things you just described are part of the ARISCAT score and other ones, for example, the severity of lung disease is not necessarily a part of that score.

Preethi Patel, MD:

Nope, it isn't. It is not. So, it's a thought-provoking question. ILD for one is not included in any of the scoring that has one of the highest post-op pulmonary complication rate and there's nothing we can do about it. The risk of ILD worsening in the post-op setting is very high. So, in those patients, it's the best we can do. If we can avoid a prolonged surgery, that's again, a shared medical decision that we want to do. And that's the whole idea of the pre-op clinic is we bring everybody together to say, "Okay, this patient is high risk. How could we mitigate some of this non-modifiable? Can we do a shorter surgery? Can we avoid general anesthesia? Can we avoid neuromuscular blockage in these patients? Do they have pulmonary hypertension? Is that something we need to assess for? Do we need to send them back to their pulmonologist to say what else we can do? And unfortunately, a lot of these things are not modifiable.

Dan Culver, MD:

So, you're really looking at number one, raising awareness and everybody being above board about what's happening before surgery, modifying the modifiable and then having a direct discussion across the team about the benefits of the surgery and how to proceed. I wonder one of the things that has come up sometimes and perhaps it's a bit now in the rear-view mirror, but still people ask about giving a course of steroids in patients with COPD before surgery to cut down on mucous secretion or to help control wheezing. What do you do in your practice?

Preethi Patel, MD:

So, if the patient is actively wheezing, especially if it's a patient with uncontrolled COPD at baseline requiring multiple courses of rescue inhalers, those patients we definitely do a short course of steroids and there's very good data to say that really does not harm patient outcomes in any way. In fact, it may be beneficial. There's one thing about adrenal insufficiency and these are patients who are really severe COPD who are on multiple courses of steroids over the years. Those are somebody we worry about, but again, if you think about it, we can fix it. But preemptively to give steroids for patient who has well controlled disease, that's not something that's necessary or is advisable.

Dan Culver, MD:

Do you have any numbers that you use? So, you mentioned some of the tests, but do you have some specific cutoffs that you use to either decide to escalate treatment or where you would call up the surgeon or the anesthesiologist and say, "I'm not happy with what I see here?"

Preethi Patel, MD:

So, we don't do bedside spirometry routinely in the clinic. We look at the spirometry data, and we look to see patients which are really high risk and high COPD, goal classification is extremely high and patients are severe COPD. In those patients, we basically looking at what is their underlying baseline medical treatment like if that is optimized or not. There are other things like VO2 max. There are other things like six-minute walk tests, but none of them have been validated or proven to say, "Okay, these are the numbers we're going to use where we're going to be treating." So, it's completely clinical decision making at the time that we're seeing the patient.

Dan Culver, MD:

I suppose oxygen requirement and the presence of hypercapnia are important.

Preethi Patel, MD:

Yeah. So those are important and we see patients who have baseline hypercapnia to begin with. They have compensated. So, if you notice that they're going into the decompensated stage, those are the patients we don't want to send for elective surgery in any way.

Dan Culver, MD:

Sure. You mentioned a little bit about some of the choices of anesthesia strategies, and I wonder if you ever have conversations with the anesthesia team about the ventilator strategy, especially with certain underlying diseases.

Preethi Patel, MD:

Well, we do talk about it just for them educating us more than the other way around, but one of the things that has come up quite a bit is the same strategy that is developed in the ICU for ARDS patients. So, the lung preserving mechanical ventilation with low tidal volumes and a higher PEEP levels, to bring down the driving pressure or reducing barrier trauma and there's been several studies. One was recently published in 2025 that looked at the strategy with a multicenter analysis, and it actually showed to improve outcomes in those patients.

Dan Culver, MD:

Yeah. I think that especially with interstitial lung disease, high stretch certainly can be damaging to the lungs. So, I'm glad that that's now become really widespread knowledge, and I think that that's pretty routinely employed now. Hopefully, that's leading to better outcomes. I recall when I was in training, almost everybody in the ICU had ARDS. We thought that was just part of being in the ICU and it really had to do with the ventilator strategy more than the underlying disease.

Preethi Patel, MD:

Right. Yeah. And again, I had to read up about this too, about customizable to patients individualized and lung recruitment maneuvers that they're using these sign breadths. It's very fascinating to say how we're trying to bring physiology into the ICU just to say, okay, this is how normal people breathe and putting high tidal volumes is not the way to go.

Dan Culver, MD:

It might make the numbers look good, but it doesn't help the patient.

Dan Culver, MD:

So, we've gotten through the preoperative assessment, the patient has gone into the OR and come out and now you're involved in the care and I wonder if you can talk a little bit about some of the postoperative strategies and specifically maybe about postoperative CPAP and where that might be useful.

Preethi Patel, MD:

So, the use of postoperative CPAP again has, you know how evidence you use through the years. So, I think in 2008 when the first study started to come out, especially in abdominal surgery patients, there was signal towards there's a benefit of using CPAP in these patients. A couple of years later, this huge PRISM study came out. This was the largest, pragmatic trial that came out in 2021, I think. And it had about 2,400 patients, and that really did not show any benefit of using CPAP preemptively for all patients with abdominal surgeries. And subsequent meta-analysis also pretty much said there is no benefit that we see by using preemptive CPAP. That said, there are a subset of patients that it's useful for, especially sleep apnea patients. So, if you have sleep apnea, severe sleep apnea, especially that is very beneficial to continue CPAP in the post-op setting. Similarly, in post-extubation hypoxia patients using non-invasive ventilation CPAP does reduce reintubation rates in those patients.

Dan Culver, MD:

What about in patients who are simply obese and who may have low tidal volumes and difficulty recruiting after surgery? Would you use it in those patients whether or not they have Pickwickian syndrome?

Preethi Patel, MD:

I would, especially if they are undiagnosed sleep apnea patients, that is somebody I would definitely try CPAP on.

Dan Culver, MD:

Great. Well, it's been nice kind of hearing your approach to this thing. I wonder if you can speculate for me a little bit about what will this whole practice look like in 10 or 20 years? What do you see changing in the field?

Preethi Patel, MD:

I think what you're going to see is a lot more individualized customizable practices that we're going to be doing. We're doing so much of ventilator management and stuff like that already in the intra-op and much more gentler way of approaching ventilation in the post-op as well. That is one thing that's going to continue to evolve. Another thing, I think pain management strategies are also going to evolve quite a bit because we are using a lot more, especially in the post-op abdominal, but these are patients we're talking about abdominal and thoracic surgery. So, the blocks that they're using to avoid using systemic opioids for patients, that's always going to be helpful, and I think that'll lead to quicker recovery times and less post-op complications as well. And I think anesthesia techniques are just getting better and better. Our anesthesiology colleagues are so confident that we are never going to lose a patient on the table. It's always going to be post-op. So, I think a lot of the emphasis will start getting to these ERAS, the enhanced recovery maneuvers, and bundled care postoperatively, that I think you're going to see a lot of that.

Dan Culver, MD:

Enhanced recovery maneuvers. Tell me more about that.

Preethi Patel, MD:

So enhanced recovery are the ERAS protocols are something that we bundle protocols that the anesthesia department uses quite a bit and it's basically starts with this pre-op, intra-op, post-op, the entire bundled care management for optimal surgical outcome. So even starts with, how long do you want to keep the patient NPO for? Do you need the patient to be NPO 24 hours after midnight? So, to reduce dehydration, we now changed our NPO orders where we saying, "You can drink clear liquids up to two hours prior to coming into the surgical time." So that way patients are not dehydrated, coming into the procedure itself. That said similarly, much more gentler way of approaching ventilation in the intraop and postoperatively mobility, physical therapy, preoperatively increased chest physiotherapy, like trying to do incentive spirometry training even before going into surgery for these patients. So, things like that into the bundled care. I think we're going to see a lot more and a lot more adapting of those techniques.

Dan Culver, MD:

That's exciting. And it sounds to me like what's really happening is that many of the conventional laws are being challenged and perhaps studied the idea of being NPO, the idea of when you can mobilize how to ventilate patients and perhaps more individualized to the particular patient.

Dan Culver, MD:

Preethi, I want to thank you very much for joining me today. It was really nice to hear about your perspective on perioperative management and preoperative assessment of pulmonary risk factors. It’s been nice talking to you.

Preethi Patel, MD:

Thank you so much for having me.

Dan Culver, MD:

Thank you everybody for joining us for this edition of Respiratory Exchange. We look forward to seeing you next time.

Raed Dweik, MD:

Thank you for listening to this episode of the Respiratory Exchange Podcast. You can find additional podcast episodes on our website, clevelandclinic.org/podcasts or wherever you get your podcasts.