by Michael Wong, JD (Executive Director, Physician-Patient Alliance for Health & Safety)

The Physician-Patient Alliance for Health & Safety (PPAHS) had the pleasure of interviewing Thomas W. Frederickson, MD, FACP, SFHM, MBA – lead author of the Society of Hospital Medicine RADEO guide (“Reducing Adverse Drug Events Related to Opioids”).  The guide is a comprehensive clinician manual created with the aim to decrease opioid-related adverse events in an inpatient setting.

In the first of this two-part interview, Dr. Frederickson discusses five key steps to identify and address patient conditions that pose a greater risk of respiratory depression.  For readers that have yet to listen to the podcast, please click here; it’s an insightful interview relevant for any clinician working in quality improvement or directly with patients prescribed opioids.

In part two, interviewer Pat Iyer and Dr. Frederickson switches gears and focuses on monitoring issues associated with caring for at-risk patients.  You can watch/listen to the interview below:

The discussion touches many topics related to monitoring for respiratory depression.  Three key takeaways are strategies to improve the monitoring of patients receiving opioids.

#1. Account for supplemental oxygen when monitoring

Interviewer, Pat Iyer, points out that use of supplemental oxygen is a nearly automatic reaction for patients receiving opioids.  However, administering supplemental oxygen adds an additional complication to monitoring that must be addressed, says Dr. Frederickson:

“[I]n opioid-induced respiratory or opioid induced respiratory failure, decrease in the oxygen saturation is a late marker rather than early warning sign. So, if you’re monitoring oxygen saturation as a strategy to detect respiratory failure early, you have to understand that it’s not an early warning sign – in fact is a late sign.  So, if you add oxygen supplemental oxygen it delays that effect even further.”

#2. Develop a comprehensive monitoring strategy

According to Dr. Frederickson, a key to accounting for such lagging indicators of respiratory depression is the development of a comprehensive monitoring strategy, including pulse oximetry and capnography.  During the interview, he highlights the unique advantages and limitations of these monitoring technologies.

Pulse oximetry is a common monitoring technology that several facilities have successfully implemented in the care of patients receiving opioids, says Dr. Frederickson:

“[T]here have been studies that have shown that continuous pulse oximetry, as part of a comprehensive monitoring program, that includes monitoring of vital signs and nurse monitoring of sedation, has decreased the rate of unexpected transfers to the ICU or decreased the need for rescue medications.”

#3. Recognize that pulse oximeters are a late marker of respiratory failure

However, in particular with the case of supplemental oxygen administration, the signs of respiratory depression can only be recognized in its later stages:

“Certainly, the limitation that we just talked about – decreased oxygen saturation tends to be a late marker of respiratory failure, not an early marker.”

#4. Monitoring with capnography provides an earlier warning of respiratory distress

Capnography can provide an earlier warning of respiratory distress, most notably for patients with the highest risk profiles, such as those with obstructive sleep apnea, which  Dr. Frederickson discussed in detail during part one of his interview. In the second part of the interview, Dr. Frederickson said that there are great benefits to monitoring patients with capnography:

“[I]t gets at more of the early warning signs of respiratory depression and respiratory failure.  It approximates that minute ventilation that we talked about, by looking at the approximation of end tidal CO2 and kind of continuously monitoring the respiratory rate. So, it does give you a little bit of an insight – more of an insight than pulse oximetry would to what’s happening in terms of early warning for impending respiratory failure.”

Dr. Frederickson notes that in addition to the benefits, clinicians monitoring with capnography should pay attention to the patient’s trends, and not necessarily the specific number:

“Trends and end tidal CO2 tend to be much more important than absolute numbers, and that’s harder to monitor a trend than it is an absolute number.”

#5. Understand the 3 critical patterns of unexpected hospital deaths and how to intervene

Dr. Frederickson ends the interview by talking about what studies have revealed about three clinical patterns of unexpected hospital deaths.  Most importantly, he emphasizes that opioids can play a part in all three patterns, with overlapping mechanisms of action:

1. Tissue injury

“This could be trauma, or congestive heart failure, sepsis, pulmonary embolism – any of those types of medical or trauma type insults that cause tissue injury because the resulting underlying physiologic disturbance tends to be metabolic acidosis.So, what we see when we look and monitor vital signs and so on is an increased respiratory rate – tachypnea.  And, that’s really a compensatory mechanism in these folks with the type one potential respiratory failure.”

2. Medication

“This tends to be associated with a lower respiratory rate, decreased minute ventilation, and the slow increase in end tidal CO2. This can happen over a fairly short period of time – fifteen minutes – but, it can also happen over hours.  What happens is eventually – as the end tidal CO2 or the partial pressure of carbon dioxide increases, and the patient’s ability to compensate again is lost – and respiratory arrest ensues and that’s what causes the patient’s death.

3. Sleep Apnea

“When you add a sedating medication such as an opioid into that mix, the patient’s ability to depend on arousal and to keep the respiratory mechanisms in place is impaired. And, that’s when the partial pressure of carbon dioxide continues to go up, oxygen saturation precipitously falls, and this patient – from the period of time when they no longer arouse themselves, when they no longer wake up to respiratory failure – it’s literally just a matter of minutes.”

We hope that you’ve enjoyed this two-part interview with Dr. Thomas Frederickson, lead author of the RADEO guide.

For a transcript of the interview, please click here.