Universal in-hospital respiratory depression monitoring after surgery
Myron Yaster MD, Jayant K. Desphande MD, and Justin L. Lockman MD MSEd
I’ve got to admit that I’ve been interested in the issue of monitoring for impending respiratory depression for decades.1 When my colleagues and I started the pediatric pain service at Johns Hopkins in 1989, we didn’t know how, or even whether, we could safely administer opioids to pediatric patients, particularly those less than 5 years of age. Could PCA be used? And in what age group? Could nurses or parents initiate a demand dose? Were background basal infusions safe? Additionally, there were many other non-pain patients we knew were at increased risk of respiratory depression who also needed respiratory monitoring like the very young (less than 60+ weeks post-conceptual age) following general anesthesia and surgery, patients with sleep disordered breathing, patients receiving opioids either alone or combined with sedative hypnotics, etc.
At the time and even today, the most common technique to evaluate respiration is for a human (usually a nurse or a nursing assistant) to visually or acoustically (via stethoscope) count respirations (as part of interval vital signs). Obviously, this is labor intensive, episodic, and occurs only haphazardly and randomly – sometimes only a few times per day! Should electronic vigilance/surveillance aids ("monitors") be used? And if so, in whom? Everyone or only the highest risk patients? Who are the highest risk patients? Where should patients be monitored? The ICU, step down unit, regular wards? And who should monitor the monitors and where should that person be located (centrally in a command center or locally on each inpatient unit)?
Most electronic vigilance aids monitor patients continuously and have alarm systems to alert caretakers of a problem. However, these monitors are hardly a panacea. The alarms must be sensitive enough to detect a problem (avoid “false negatives”) but not so sensitive that they alarm when no event occurs (avoid "false positives"). Patients must tolerate wearing these devices; removing the monitor or having it fall off will lead to a false alarm and great annoyance by both the patient and nursing staff.1 In fact, false alarms are so common with many of our monitors that alarm fatigue is now a daily part of life in hospitals.
More than 30 years later, many of these questions remain largely unanswered. In today’s PAAD2 and accompanying editorial,3 Blike et al and Ramachandran review many of the issues revolving around in-hospital, post operative monitoring in ADULT patients. And note: although the titles say “continuous monitoring,” they are really discussing respiratory monitoring only. The pro/con discussion touches on many issues that are just as true and relevant in our pediatric patients as they are in adults. I thought this would be a perfect PAAD review and discussion to read over your morning coffee! Myron Yaster MD
Original article
Blike GT, McGrath SP, Ochs Kinney MA, Gali B. Pro-Con Debate: Universal Versus Selective Continuous Monitoring of Postoperative Patients. Anesth Analg. 2024 May 1;138(5):955-966. doi: 10.1213/ANE.0000000000006840. Epub 2024 Apr 15. PMID: 38621283.
Editorial
Ramachandran SK. Enhanced Postoperative Monitoring: Mixed Realities and New Frontiers. Anesth Analg. 2024 May 1;138(5):951-954. doi: 10.1213/ANE.0000000000006903. Epub 2024 Apr 15. PMID: 38621282.
Respiratory complications are common after surgery, and in ADULTS result in significantly increased mortality.4 Further, recent literature indicates that vital sign abnormalities, particularly low oxyhemoglobin saturation, often occur up to 4 hours before inpatient cardiopulmonary events occur.5 “The physiology of postoperative respiratory dysfunction is well known and can be caused by residual anesthetic and neuromuscular blocking agents, analgesic regimens, combinations of sedative agents, and patient positioning.”2 [We would also add, particularly in children, underlying patient anatomic and/or physiologic risks.] The primary culprits are opioids, administered alone or combined with sedatives or gabapentin, for postoperative pain relief. Aside from higher ASA PS status (>3), obstructive sleep apnea is another important risk factor.6 The Anesthesia Patient Safety Foundation (APSF) has stated, “No patient shall be harmed by opioid induced respiratory depression (OIRD) in the postoperative period.”7 To prevent clinically significant OIRD, the guidelines from the APSF and the American Society for Pain Management Nursing recommend that all patients given postoperative opioids be continuously monitored.
Although titled a “pro/con debate,” we think there is no debate that monitoring for respiratory depression is the right thing to do. The question is “in whom?”: everyone or select/high-risk patients?
“The Pro argument advocates for continuous postoperative monitoring of ALL patients until hospital discharge by use of a surveillance-specific system at the bedside. This approach recognizes that patients requiring postoperative hospitalization are at sufficient risk of acute respiratory decompensation during their entire hospitalization and should be continuously monitored, which allows for early detection and prevention of severe respiratory depression events. A safety net surveillance system using continuous pulse oximetry can provide the needed monitoring to detect serious but treatable complications and to mobilize timely rescue by rapid response teams (RRTs). In addition, we argue that the cost of such a system is budget neutral and in fact has a positive return on investment, and that alarm fatigue can be readily managed if the system is configured properly. Note that applying risk prediction and selective monitoring with a centralized service is associated with institutional cost and will still be unreliable, allowing for preventable harm in unmonitored individuals at risk.”2
“The Con argument advocates that patients receiving opioids postoperatively should have continuous pulse oximetry and that a targeted and more nuanced approach should be used to identify patients at increased risk and to select appropriate levels of monitoring for these patients. More intensive centralized monitoring should be used for patients at high risk of respiratory compromise by screening for OSA, by using tools such as the ARISCAT or PRODIGY score, and by using PACU scoring systems for patients known to be at high risk. Resources can then be targeted for this patient population, thereby minimizing the risks of alarm fatigue for nurses, minimizing the overutilization of limited high-level monitoring systems, decreasing infrastructure needs in a rapidly changing health care environment, and decreasing overall health care costs. Because patients have abnormal vital signs several hours before their respiratory condition deteriorates, robust RRTs can also be a resource health care institutions use to prevent respiratory decompensation. Thus, a targeted approach to use of monitoring systems can allow health care institutions to focus on value of care by identifying systems that can provide high-quality, safe patient care.”2
What monitors are they actually advocating for and will these monitors work in “combat” in pediatric patients? Acceptance of monitors by the patient and nursing staff “decreases as complexity, weight, wires, and nuisance alarms increase.” I (MY) learned this years ago in a study I did with Dr. Connie Monitto and others looking at capnography and impedance pneumography.1 Although capnography may be the gold standard in adults, it simply didn’t work in pediatrics because the patients wouldn’t wear the nasal yoke continuously. In today’s PAAD, the primary respiratory monitor the authors advocate for is continuous pulse oximetry. Although well tolerated by children, we think it isn’t a very good monitor as an early warning respiratory depression detection system. Most patients don’t become hypoxemic for several minutes after apnea. Further, if the patient is receiving supplemental oxygen, which is very common in perioperative patients, hypoxemia occurs very late in the cycle. Indeed, in what we know is a very controversial statement, I (MY) have advocated for room air rather than supplemental oxygen in monitored anesthesia care or when using nasal cannula during propofol general anesthesia. Again, the reason was simple. By giving supplemental oxygen, pulse oximetry becomes a very late sign of respiratory depression.
Are there alternative monitors? Yes, although we are unsure if anyone is using them routinely. One, transcutaneous CO2 monitors, have been around for a long time but have never really caught on except in (N)ICUs (for patients on high-frequency ventilation, for example) and select surgical indications.8 This monitor is also limited by a slow response rate to sudden apnea, although hypopnea would be readily picked up. Alternatively, thoracic bioimpedance monitors (ExSpiron, Senzime, Inc.) can be used to noninvasively detect respiratory rate and tidal volume.9 We’ve seen the ExSpiron monitor demonstrated at ASA meetings and have no personal experience with the monitors. We think it may fulfill the needs of patient tolerability and as an early warning pediatric respiratory depression monitor and has been studied in children. Is anyone using this monitor? Finally, isn’t about time that we get past wired monitors and get wireless technology for all of our monitors, in the OR, PACU, ICU, and on the floors? Aren’t you fed up with the tangle of wires that you have to untangle when you bring a patient to the PACU or ICU?
We are concluding today’s PAAD by reaching out to those of you in academic practices. It’s past time to investigate how to monitor and prevent respiratory depression in pediatric patients of all ages. There is so much we don’t know and need to know. Please send Myron your experience with these or other monitors and we’ll post in a Friday Reader Response.
References
1. Miller KM, Kim AY, Yaster M, et al. Long-term tolerability of capnography and respiratory inductance plethysmography for respiratory monitoring in pediatric patients treated with patient-controlled analgesia. Paediatric anaesthesia 2015;25(10):1054-9. (In eng). DOI: 10.1111/pan.12702.
2. Blike GT, McGrath SP, Ochs Kinney MA, Gali B. Pro-Con Debate: Universal Versus Selective Continuous Monitoring of Postoperative Patients. Anesthesia and analgesia 2024;138(5):955-966. (In eng). DOI: 10.1213/ane.0000000000006840.
3. Ramachandran SK. Enhanced Postoperative Monitoring: Mixed Realities and New Frontiers. Anesthesia and analgesia 2024;138(5):951-954. (In eng). DOI: 10.1213/ane.0000000000006903.
4. Fernandez-Bustamante A, Frendl G, Sprung J, et al. Postoperative Pulmonary Complications, Early Mortality, and Hospital Stay Following Noncardiothoracic Surgery: A Multicenter Study by the Perioperative Research Network Investigators. JAMA surgery 2017;152(2):157-166. (In eng). DOI: 10.1001/jamasurg.2016.4065.
5. Andersen LW, Kim WY, Chase M, et al. The prevalence and significance of abnormal vital signs prior to in-hospital cardiac arrest. Resuscitation 2016;98:112-7. (In eng). DOI: 10.1016/j.resuscitation.2015.08.016.
6. Sun X, Yu J, Luo J, Xu S, Yang N, Wang Y. Meta-analysis of the association between obstructive sleep apnea and postoperative complications. Sleep Med 2022;91:1-11. (In eng). DOI: 10.1016/j.sleep.2021.11.019.
7. Weinger MB, Lee LA. No patient shall be harmed by opioid-induced respiratory depression. APsF Newsletter 2011;26(2):21.
8. Halani SH, Hembd AS, Li X, et al. Flap Monitoring Using Transcutaneous Oxygen or Carbon Dioxide Measurements. J Hand Microsurg 2022;14(1):10-18. (In eng). DOI: 10.1055/s-0040-1718862.
9. Atkinson DB, Sens BA, Bernier RS, Gomez-Morad AD, Imsirovic J, Nasr VG. The Evaluation of a Noninvasive Respiratory Volume Monitor in Mechanically Ventilated Neonates and Infants. Anesthesia and analgesia 2022;134(1):141-148. (In eng). DOI: 10.1213/ane.0000000000005562.