Opioid-induced suppression of genioglossal muscle activity: is it clinically important?

Sleep apnea syndrome in patients with methadone or buprenorphine

OBJECTIVES

This work aimed to assess the association between sleep apnea syndrome (SAS) and opioid substitution treatments (OST) dose/timing of administration in patients receiving methadone or buprenorphine for an opioid use disorder (OUD).

METHODS

We conducted a retrospective cross-sectional study by including files of adult patients treated between November 2015 and January 2023 with methadone or buprenorphine and who had a nocturnal respiratory polygraphy. We collected information on treatments and polygraphical recording data such as the apnea-hypopnea index (AHI).

RESULTS

We enrolled 60 patients on methadone and 15 on buprenorphine. The sample encompassed 72% of males, and the mean age was 36±7.49years. Moderate to severe and severe SAS were significantly associated with the daily dose and the evening administration but was not predicted by the type of OST. However, the mean and median values of AIH were significantly greater with methadone. Contrary to methadone, there was no significant correlation between the buprenorphine daily dose and the AHI. The best sensitivities and specificities for the prediction of an AHI≥15 events/h and an AHI≥30 events/h were respectively obtained with methadone dose thresholds of 77.5mg/day.

CONCLUSIONS

In this sample, the methadone daily dose of 77.5mg was the best cut-point to predict moderate to severe SAS, especially while taken in the evening, and we found no correlation between buprenorphine and the AHI. These results draw clinicians' attention to buprenorphine use as an alternative for patients treated with methadone and having SAS.

Low-Dose Ketamine Infusion for Perioperative Pain Management in Patients Undergoing Laparoscopic Gastric Bypass: A Prospective Randomized Controlled Trial

Introduction

Obesity is a common comorbidity seen in the perioperative setting and is associated with many diseases including cardiovascular disease and obstructive sleep apnea. Laparoscopic Roux-en-Y gastric bypass is the gold standard surgical treatment for patients whose weight is refractory to diet and exercise. Caring for these patients perioperatively presents unique challenges to anesthesiologists and is associated with an increased risk of adverse respiratory events. In our study, we hypothesize that a low-dose perioperative ketamine infusion will reduce opioid consumption and improve analgesia when compared to standard therapy.

Methods

This is a single-center, prospective randomized controlled study enrolling 35 patients in total. Patients were randomized equally into the ketamine and control group. Preop, intraop, and postop management regimens were standardized. The ketamine group received a 0.3 mg/kg ideal body weight ketamine bolus after induction followed by a 0.2 mg/kg/hr ketamine infusion continued into the postop setting for up to 24 hours. Data collected included total perioperative opioids used converted to oral morphine equivalents (ME), pain scores, side effects, hospital length of stay, and patient satisfaction captured via postoperative questionnaires.

Results

The use of perioperative opioid consumption was significantly lower in the ketamine group when compared with the control group (179.9 ME versus 248.7 ME, P=0.03). There was no statistically significant difference in pain scores or hospital length of stay postoperatively between the two groups. There were also no reported adverse respiratory events, prolonged sedation, agitation, or other side effects reported in either group. The patient satisfaction questionnaires showed a significant difference with the ketamine group reporting lower maximum pain scores, a decrease in how pain limited activities of daily living once discharged, and increased hospital pain management satisfaction scores.

Conclusions

Perioperative low-dose ketamine infusions significantly reduced opioid consumption in morbidly obese patients undergoing laparoscopic gastric bypass surgery.

Observation following Tonsillectomy May Be Inadequate Due to Silent Death

The focus on the first 24 hours of care for respiratory events following tonsillectomy may be misplaced and a broader focus is warranted. Nocturnal hypoxemia, an elevated apnea-hypopnea index, or obstructive sleep apnea contributes to an increased sensitivity to narcotics and postoperative complications. Narcotic pain management depresses respiration through an increase in the frequency of central sleep apnea, decreased minute ventilation, increased hypercarbia pressure, and a decrease in the hypoxic ventilator response. Residual pain gives some margin of safety as it stimulates respiration. Children dying following tonsillectomy do so silently during sleep, often without arousing the attention of caregivers or nursing personnel in close proximity. Perioperative education of caregivers, use of the least morbid surgical technique, and the control of pain rather than its elimination are prudent steps in the management of tonsillectomy patients.

A critical assessment of monitoring practices, patient deterioration, and alarm fatigue on inpatient wards: a review

Approximately forty million surgeries take place annually in the United States, many of them requiring overnight or lengthier post operative stays in the over five thousand hospitals that comprise our acute healthcare system. Leading up to this Century, it was common for most hospitalized patients and their families to believe that being surrounded by well-trained nurses and physicians assured their safety. That bubble burst with the Institute of Medicine's 1999 report: To Err Is Human, followed closely by its 2001 report: Crossing the Quality Chasm. This review article discusses unexpected, potentially lethal respiratory complications known for being difficult to detect early, especially in postoperative patients recovering on hospital general care floors (GCF). We have designed our physiologic explanations and simplified cognitive framework to give our front line clinical nurses a thorough, easy-to-recall understanding of just how these events evolve, and how to detect them early when most amenable to treatment. Our review will also discuss currently available practices in general care floor monitoring that can both improve patient safety and significantly reduce monitor associated alarm fatigue.

Neural control of the upper airway: integrative physiological mechanisms and relevance for sleep disordered breathing

The various neural mechanisms affecting the control of the upper airway muscles are discussed in this review, with particular emphasis on structure-function relationships and integrative physiological motor-control processes. Particular foci of attention include the respiratory function of the upper airway muscles, and the various reflex mechanisms underlying their control, specifically the reflex responses to changes in airway pressure, reflexes from pulmonary receptors, chemoreceptor and baroreceptor reflexes, and postural effects on upper airway motor control. This article also addresses the determinants of upper airway collapsibility and the influence of neural drive to the upper airway muscles, and the influence of common drugs such as ethanol, sedative hypnotics, and opioids on upper airway motor control. In addition to an examination of these basic physiological mechanisms, consideration is given throughout this review as to how these mechanisms relate to integrative function in the intact normal upper airway in wakefulness and sleep, and how they may be involved in the pathogenesis of clinical problems such obstructive sleep apnea hypopnea.

Patterns of unexpected in-hospital deaths: a root cause analysis

BACKGROUND

Respiratory alarm monitoring and rapid response team alerts on hospital general floors are based on detection of simple numeric threshold breaches. Although some uncontrolled observation trials in select patient populations have been encouraging, randomized controlled trials suggest that this simplistic approach may not reduce the unexpected death rate in this complex environment. The purpose of this review is to examine the history and scientific basis for threshold alarms and to compare thresholds with the actual pathophysiologic patterns of evolving death which must be timely detected.

METHODS

The Pubmed database was searched for articles relating to methods for triggering rapid response teams and respiratory alarms and these were contrasted with the fundamental timed pathophysiologic patterns of death which evolve due to sepsis, congestive heart failure, pulmonary embolism, hypoventilation, narcotic overdose, and sleep apnea.

RESULTS

In contrast to the simplicity of the numeric threshold breach method of generating alerts, the actual patterns of evolving death are complex and do not share common features until near death. On hospital general floors, unexpected clinical instability leading to death often progresses along three distinct patterns which can be designated as Types I, II and III. Type I is a pattern comprised of hyperventilation compensated respiratory failure typical of congestive heart failure and sepsis. Here, early hyperventilation and respiratory alkalosis can conceal the onset of instability. Type II is the pattern of classic CO2 narcosis. Type III occurs only during sleep and is a pattern of ventilation and SPO2 cycling caused by instability of ventilation and/or upper airway control followed by precipitous and fatal oxygen desaturation if arousal failure is induced by narcotics and/or sedation.

CONCLUSION

The traditional threshold breach method of detecting instability on hospital wards was not scientifically derived; explaining the failure of threshold based monitoring and rapid response team activation in randomized trials. Furthermore, the thresholds themselves are arbitrary and capricious. There are three common fundamental pathophysiologic patterns of unexpected hospital death. These patterns are too complex for early detection by any unifying numeric threshold. New methods and technologies which detect and identify the actual patterns of evolving death should be investigated.