Episode #42 Keeping Patients with Obstructive Sleep Apnea Safe During Anesthesia Care

Hello and welcome back to the Anesthesia Patient Safety Podcast.  My name is Alli Bechtel and I am your host. Thank you for joining us for another show.

Today, we are going to explore the APSF Newsletter archives.  For this episode and past and future similar shows, we will take a look at past articles that were published in the APSF Newsletter that you can find on our website. Keep in mind that things may have changed a lot since the publication of these articles, but they are of interest from our archives.

I hope you have your cup of coffee ready or you are out on an invigorating walk as we get ready to explore the past by looking at an area that is so important for patient safety, Obstructive Sleep Apnea!!  This remains one of the most frequently visited pages on the ASPF website. There is so much to talk about related to obstructive sleep apnea and anesthesia patient safety, but for our first show on the topic we are going all the way back to 1997 to look at factors associated with OSA and patient safety along with pre-op, intra-op, and post-op considerations. This is a big topic related to anesthesia patient safety and a lot has changed since then which will give us plenty to talk about on future shows!

Before we dive into today’s episode, we’d like to recognize Masimo, a major corporate supporter of APSF. Masimo has generously provided unrestricted support to further our vision that “no one shall be harmed by anesthesia care”. Thank you, Masimo – we wouldn’t be able to do all that we do without you!”

Now, let me set the scene for you. It is summer back in 1997 and we are discussing the article, “Anesthesia Safety Always an Issue with Obstructive Sleep Apnea” by Ogan and Plevak. To follow along with us, head over to APSF.org and click on the Newsletter heading, fourth one down is the Newsletter archives, then, scroll way down to 1997 and click on Summer 1997. Look over at the left hand column and the third one down is our featured article today. The authors begin by discussing the scope of the problem since patients with sleep apnea including obstructive sleep apnea or OSA , central, or mixed sleep apnea may require additional monitoring and care before, during, and after undergoing an anesthetic to help keep these patients safe. If we look a little closer at the different types of sleep apnea, we can see that for central sleep apnea the additional considerations include the following: making sure to ask the patient about snoring since this will require that the patients are treated in a similar manner to those with OSA, determining if the etiology is from heart failure and evaluating the patient for underlying heart disease, and evaluating for hypoventilation syndrome and being prepared to provide ventilatory support throughout the perioperative time period if needed.

Let’s switch gears to talk about OSA. We often see patients with OSA coming to the OR for surgery. The pathophysiology is important since OSA involves episodes of upper airway obstruction during sleep with associated sleep disruption and patient are at risk for hypoxemia and arterial oxygen desaturation. The cause of the obstruction or anatomic narrowing in the upper airway may be due to abnormal neuromuscular tone, redundant soft tissue, or increased upper airway adipose tissue. Obesity is a risk factor for OSA, but patients do not have to be overweight to suffer from obstructive sleep apnea especially if they have tonsillar hypertrophy or other craniofacial abnormalities. Patients with OSA who have recurrent or prolonged episodes of arterial oxygen desaturation may go on to develop cardiac and lung abnormalities such as systemic and pulmonary hypertension, cardiac rhythm abnormalities, and even right heart failure which is known as cor pulmonale. Not only does OSA put patients at risk during anesthesia care, but these secondary problems can also put patients at risk. This is way the preoperative evaluation is so important.

That is our next stop on this journey into the past, the Preoperative Assessment. A thorough medical history and physical exam is the foundation for the preoperative assessment. Did you remember to ask your patient if they have a history of sleep apnea? This is a common question, but even when patients answer, “No,” we still need to continue to investigate. OSA can occur in men and women, although it is most common in men, in patients in any BMI range, although it is more likely in overweight and obese patients, and in patient in any age range, although it is more common in adults over the age of 40 years old. Children with tonsillar hypertrophy may have OSA as well. The authors provide a list of important questions to ask during the preoperative evaluation.

• Do you snore nightly?
• Has anyone ever said that you stop breathing in your sleep?
• Do you feel tired and groggy on awakening?
• Do you fall asleep easily during the day?
• Do you frequently have headaches in the morning? (but keep in mind that this symptom is non-specific.)

Many pre-operative anesthesia clinics and anesthesia professionals use the STOP-BANG questionnaire as a tool to screen patients for OSA. The questions in the STOP-BANG include the following and I will include a link to the website and STOP-BANG calculator in the show notes as well.

1. Do you Snore Loudly?
2. Do you often feel Tired, Fatigued, or Sleepy during the daytime?
3. Has anyone Observed you Stop Breathing or Choking/Gasping during sleep?
4. Do you have or are you being treated for High Blood Pressure?
5. Is your Body Mass Index greater than 35kg/m2
6. Are you older than 50 years old?
7. Is your shirt collar 16 inches or 40 cm or larger as measured around your Adams Apple?
8. Is your gender Male?

The results of the STOP-BANG depend on how many times the patient answered YES to the above questions. Low risk for OSA occurs with YES answered in 0-2 questions, Intermediate risk occurs with Yes answered in 3-4 questions and high risk for OSA occurs with YES answered in 5-8 questions.

For patients who screen positive or reveal that they have OSA during the preoperative visit, it is important to evaluate results from their sleep study if one was conducted to determine the severity of their disease. Patients who do not undergo a sleep study may not be able to help quantify the severity of their OSA in terms of daytime sleepiness and disruptions during the nighttime. The next step is to ask about problems with anesthesia in the past and review all available records from prior anesthesia and surgery events to see what type of anesthesia the patient may have had and if there were any adverse events or additional monitoring required. Don’t forget to evaluate the patient for any cardiac or pulmonary disease as well.

Next up, is the physical exam which will provide information about upper body obesity and large neck circumference as well as a cardiac and pulmonary examination. It is so important to evaluate the patient’s airway and assess for any potential difficulty with intubation or mask ventilation. This evaluation often includes the Mallampati score, neck range of motion, mouth opening, tongue and teeth size, and any skeletal deformity. Additional studies may be required including an echocardiogram or pulmonary function testing.

Now, let’s head into the OR to talk about perioperative considerations. Patients with OSA may be morbidly obese as well and are at risk for aspiration during induction of general anesthesia and difficult to mask ventilate or intubate. It may also be difficult to obtain peripheral IV access and you may need to use an ultrasound to help with this. It is also important to consider holding or decreasing the dose for any preoperative anxiolysis or sedative medications for patients with OSA. Patients with OSA are more likely to be sensitive to these medications and are at risk for airway obstruction, hypoventilation, hypoxemia, and respiratory arrest. Another big threat for patients with OSA is during induction of general anesthesia and intubation. Patients with OSA and obesity are at increased risk for hypoxemia due to rapid desaturation. It is important to be prepared for a difficult airway. Appropriate positioning on the OR table for intubation with adequate pre-oxygenation and additional intubation equipment is vital. Patients may require an awake, fiberoptic intubation to help secure the airway safely prior to induction of general anesthesia. If possible, patients with OSA may benefit from avoidance of general anesthesia with a primary regional nerve block. Even for these cases though it is so important to monitor patients carefully especially when any sedation is provided and be prepared to provide ventilatory support.

There are threats to patient safety during sedation, induction of general anesthesia, and intubation and the risks do not go away at the end of the case. Patients with OSA are at risk for respiratory compromise and hypoventilation and hypoxemia during emergence and into the post-operative phase. Patients at higher risk are those who undergo surgery on their airway to treat OSA which can lead to airway swelling and inflammation as well as patients who receive longer acting sedative and analgesic medications. It may be necessary to extubate once patients are fully awake and able to follow commands. In addition, patients may require continuous positive airway pressure or CPAP after extubation in order to prevent further airway obstructive and desaturation post-operatively. The level of monitoring required during the postoperative phase depends on the type of surgery, severity of OSA, and additional comorbidities. Patients may require admission to a step-down unit or intensive care unit for additional monitoring and continued ventilatory support. Opioid-sparing techniques are often used for patients with OSA in conjunction with a multi-modal analgesic plan. For patients who do require opioid medications for pain control, it is imperative that monitoring of oxygenation and ventilation as well as EKG monitoring be used to help keep patients safe.

I will leave you with the author’s summary:

“Obstructive sleep apnea patients undergo surgery for a variety of reasons. Airway maintenance issues and frequently associated cardiopulmonary abnormalities place OSA patients at risk for perioperative complications. Safe anesthetic care can be provided by thorough preoperative assessment, a thoughtful and well-executed anesthetic plan, and vigilance which extends well into the postoperative period.”

This was true in 1997 and remains true today and going forward so it is important to stay vigilant anytime you provide anesthesia care for patients obstructive sleep apnea.

That’s all the time we have for today. If you have any questions or comments from today’s show, please email us at [email protected].

Visit APSF.org for detailed information and check out the show notes for links to all the topics we discussed today. Please keep in mind that the information in this show is provided for informational purposes only and does not constitute medical or legal advice. Are there any other articles from our archives that you would like to hear about on this podcast? If so, send us an email or tag us in a tweet using #ASPF podcast and tell us which article you would like to hear featured on this show. Thanks for listening and we can’t wait to hear from you!

Until next time, stay vigilant so that no one shall be harmed by anesthesia care.

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