Joseph Curley, MD, is employed by Upstate Anesthesia Services, P.C., and is chief of anesthesiology at St. Mary’s Hospital in Troy, N.Y. Upstate Anesthesia Services is managed by Somnia, Inc.
Q: Why is obstructive sleep apnea (OSA) becoming more of a hot topic for anesthesiologists?
Dr. Joseph Curley: It's a very topical issue because it's something we come across more and more commonly. It has been more of a topic since 2006 when the American Society of Anesthesiologists came out with its guidelines for care of the sleep apnea patient. The Anesthesia Patient Safety Foundation has also been very good about addressing this issue.
In the past there were a group of patients, identified by the asa Closed Claims Project, who postoperatively had cardiac arrest. They were otherwise "healthy patients" that had relatively peripheral surgery who were found to have had cardiac arrest after they were checked on post-operatively. No one knew why this occurred, but they had several characteristics associated with sleep apnea. They were receiving narcotics and they may have had a respiratory arrest which eventually led to cardiac arrest. When these kinds of incidents were looked into in more detail, it was found to be likely that sleep apnea may have been at the basis of some of these postoperative respiratory events.
Q: Why is OSA a significant issue of concern for anesthesiologists?
JC: It's a very serious disease that affects some 18 million people in the United States, and about 90 percent of them are not diagnosed when we see them. As anesthesiologists, we are the first physicians who are focusing on this particular area of their health. We're asking them questions about their sleep, their degree of tiredness during daytime hours, if they snore, the kind of standard diagnostic criteria that might suggest OSA because no one has really delved into that area yet.
It has significant implications because it has to do with the potential for airway obstruction not only during anesthesia but also, and most importantly for us, after anesthesia, especially if these patients are going to be getting narcotic pain medication afterwards. So there really are a lot of concerns both in terms of the vast numbers of patients affected and in terms of the severity that has implications for what might happen to patients around the time of surgery.
Q: What are you doing at St. Mary's to identify and care for these patients?
JC: I recognized that in our institution, we really did not have a program in effect to deal with these people. When we worked on patients who had been diagnosed with sleep apnea, we would be more on alert, we knew to be especially careful of their airway, we would worry about them post-op and the occasional patient we would send to ICU for monitoring, but we really didn't have a program in place to deal with the population as a whole.
So what we did was form a committee in our hospital made up of representatives from anesthesia, surgery, nursing, administration, pulmonary, respiratory therapy, and hospitalists, and we focused on how we could screen all of our surgical patients. We looked first at what was out in the literature and what other hospitals were doing. What we found was many hospitals were in exactly the same position we were: looking for the best program they could find to identify patients who were at-risk.
We adopted the STOP-BANG questionnaire where you essentially ask patients eight questions (with each question associated with each letter in STOP-BANG):
S: Does someone Snore loudly enough to be heard through a closed door?
T: Are they Tired or sleepy during the day and falling asleep in an unstimulated environment, such as riding a car?
O: Has anyone Observed them stop breathing during sleep?
P: Do they have, or are being treated for, high-blood Pressure?
B: Do they have a BMI greater than 35?
A: Are they over the Age of 50?
N: Is their Neck circumference greater than 40 cm
G: Are they the male Gender?
About a year ago we developed this screening program and put that in effect during our pre-admission testing program, so now all surgical patients, including elective, emergent, ambulatory, and inpatients, get screened with this. According to the questionnaire, if patients answer three or more of these questions positive, they are classified as high-risk for the potential of having OSA.
We then developed a flowchart (available by clicking here (pdf)) which is our perioperative process for high-risk OSA patients. We look at giving them preemptive analgesics, non-steroidal analgesics, looking at how we do their anesthesia, focusing on more regional anesthesia, peripheral nerve blocks and trying to minimize intraoperative and postoperative narcotics as much as possible.
We pay attention to the airway like we do with all patients, but recognize that with sleep apnea patients, if you are planning deep sedation, you may be better off using general anesthesia with a secured airway than you are using deep sedation with an unsecured airway because of their potential for the airway to close off. This is something that affects not just anesthesiologists but other people who are doing sedation for endoscopy procedures, for example.
Then we stratified these patients postoperatively — the patients who are high-risk who are inpatient actually get monitored with an oxygen saturation telemetry unit in the hospital and we monitor them for 24 hours to see if they have any desaturations or other airway problems.
We've also worked with the surgeons who prescribe the IV PCA pumps in patients who are on IV narcotics and there's a special order sheet (available by clicking here (gif)) we've developed through this committee so the patients who are high-risk for OSA get IV narcotics with reduced doses — they don't have a continuous dose with the IV PCA, they only get bolus doses because that's considered a safer way to provide analgesia.
Q: How has the program worked so far?
JC: It's such a low incidence event — someone having a respiratory arrest postoperatively — that it's going to be a little difficult to say how many of these did you have before the program and how many after the program. If you prevent one of those, it's huge. So far, we have had very few events that required interventions.
Ideally we'd love to have end-tidal CO2 monitoring so we could monitor ventilation and not just oxygenation. That's something we would like to have in the future that's currently not something we have available. We thought oximetry monitoring was better than no monitoring. It's a dedicated person that watches the oximetries throughout the whole hospital to pick up on events.
The program has also had a positive byproduct. We've had at least one patient who had an unrelated bradycardic event (significantly slowed heart rate) and only because they were on telemetry for watching their saturation that they also picked up this bradycardic event that necessitated treatment.
I would have to say it's been an enlightening experience to see how many patients screen in for being at high-risk. In our practice about 40 percent of our surgical patients screen in as being high-risk for OSA so I'm personally easily seeing three or four or more patients a day that are high-risk and probably with the patients who are already diagnosed with OSA and are using home CPAP machines, I'd say one or two patients a day.
Q: What do you think other anesthesiologists should be doing for patients with OSA?
JC: In your institution, you really should have some type of screening program for these patients. I’m not saying it has to be like ours but you should have some way to identify these people because perioperatively they could run into trouble.
The normal patient has about a 2 percent incidence of difficult intubation. The OSA patient it is estimated may have 15-20 percent incidence of difficult intubation. Airway tools like GlideScopes or fiberoptic intubation we've been finding are very helpful for some patients.
At the end of the case, you must extubate them when they're fully awake. We continue to see reports of a patient seeming to be awake who was extubated and then suddenly the airway was obstructed and they couldn't be reintubated because they were difficult to intubate and suffered cardiac arrest or brain damage. Make sure the muscle relaxants are fully reversed and the patient is extubated when they're fully awake and semi-sitting up instead of lying on their back. Post-operatively, OSA patients should use their CPAP machines. High Risk for OSA patients should be monitored for respiratory depression. Work cooperatively in your institutions to develop protocols.
Q: What else do you think anesthesiologists should be considering when it comes to treating patients with OSA?
JC: Sleep apnea is something that's not exclusively the domain of the obese patient but approximately 70 percent of sleep apnea patients are obese. It is estimated that for every 10 percent increase in BMI, there's a 500 percent increase in the risk of OSA so the two have very much in common.
They should think about morbidly obese obstetrical patients as having potentially these sleep apnea issues. And we're seeing more and more obese pediatric patients now. The days of the normal-sized child having a tonsillectomy are rapidly diminishing as the population becomes more obese. Those are two areas we're going to see more of in the future.
Learn more about Somnia.
Read more from Somnia:
- 8 Steps to Building a Truly Transparent Hospital
- Somnia Issues Statement Defining Accountable Anesthesia Organization Model