Extubation-Related Complications

Extubation represents an essential component of airway management. While being a common procedure in anesthesiology and critical care medicine, it is accompanied by a significant risk of morbidity and mortality. Safe extubation requires considerable skills, risk stratification and advanced planning. It is important to emphasize that intentional extubation is always an elective procedure, and as such should only be executed when conditions are optimal. The purpose of this review is to discuss the complications associated with planned extubation in the adult patient, including risk factors and management strategies, mainly focusing on the postoperative setting.

Quantified Ataxic Breathing Can Detect Opioid-Induced Respiratory Depression Earlier in Normal Volunteers Infused with Remifentanil

BACKGROUND

Ataxic breathing (AB) is a well-known manifestation of opioid effects in animals and humans, but is not routinely included in monitoring for opioid-induced respiratory depression (OIRD). We quantified AB in normal volunteers receiving increasing doses of remifentanil. We used a support vector machine (SVM) learning approach with features derived from a modified Poincaré plot. We tested the hypothesis that AB may be found when bradypnea and reduced mental status are not present.

METHODS

Twenty-six healthy volunteers (13 female) received escalating target effect-site concentrations of remifentanil with a low baseline dose of propofol to simulate typical breathing patterns in drowsy patients who had received parenteral opioids. We derived respiratory rate (RR) from respiratory inductance plethysmography, mental alertness from the Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S), and AB severity on a 0 to 4 scale (categories ranging from none to severe) from the SVM. The primary outcome measure was sensitivity and specificity for AB to detect OIRD.

RESULTS

All respiratory measurements were obtained from unperturbed subjects during steady state in 121 assessments with complete data. The sensitivity of AB for detecting OIRD by the conventional method was 92% and specificity was 28%. As expected, 69 (72%) of the instances not diagnosed as OIRD using conventional measures were observed to have at least moderate AB.

CONCLUSIONS

AB was frequently present in the absence of traditionally detected OIRD as defined by reduced mental alertness (MOAA/S score of <4) and bradypnea (RR <8 breaths/min). These results justify the need for future trials to explore replicability with other opioids and clinical utility of AB as an add-on measure in recognizing OIRD.

Perioperative Sleep Quality Disturbances in Total Joint Arthroplasty is Multifactorial

BACKGROUND

Sleep quality following arthroplasty procedures is important for patient recovery and satisfaction, but remains poorly understood. The purpose of this study was to report risk factors for sleep disturbances in the perioperative period in patients undergoing primary total joint arthroplasty procedures.

METHODS

Sleep surveys were prospectively collected on 751 consecutive patients undergoing total joint arthroplasty at our institution between June 2019 and February 2021 at their preoperative and postoperative visits (2 and 6 weeks). Data were collected on patient demographics, opioid use (preoperatively and postoperatively) as well as tobacco and alcohol use, and specific medical diagnosis that may influence sleep patterns (ie, depression). Statistical analyses were performed using the Student's t-tests and 1-way analysis of variances.

RESULTS

For both total hip and total knee patients, worse sleep patterns preoperatively were found in patients who used opioids prior to surgery (P < .001), were current smokers (P < .001), and were aged less than 65 years (P < .001). Postoperative persistent opioid use (more than 3 months) was seen in patients who had worse reported sleep quality preoperatively (P < .001). In comparison to total hip arthroplasty, patients who underwent total knee arthroplasty were more likely to report less sleep in the postoperative period. Patients who were current smokers (compared to nonsmokers or previous smokers) (P = .014) had worse sleep quality at all time points that persisted at 6 weeks, although these differences were seen more in total hip patients than in total knee patients (P = .006 versus P = .059).

CONCLUSIONS

Sleep quality disturbances around the time of surgery appear to be multifactorial.

LEVEL OF EVIDENCE

Therapeutic Level III.

External Oblique Intercostal Plane Block Versus Port-Site Infiltration for Laparoscopic Sleeve Gastrectomy: A Randomized Controlled Study

PURPOSE

Although laparoscopic sleeve gastrectomy (LSG) is a minimally invasive surgery, postoperative pain is common. A novel block, the external oblique intercostal (EOI) block, can be used as part of multimodal analgesia for upper abdominal surgeries. The aim of our study is to investigate the effectiveness of EOI block in patients undergoing LSG.

MATERIALS AND METHODS

Sixty patients were assigned into two groups either EOI or port-site infiltration (PSI). The EOI group received ultrasound-guided 30 ml 0.25% bupivacaine, while the PSI group received 5 ml of 0.25% bupivacaine at each port sites by the surgeon. Data on clinical and demographic were collected and analyzed.

RESULTS

There were no statistical differences in terms of demographic details (p > 0.05). VAS scores were statistically lower during resting at PACU, 1, 2, 4, 8, and 12 h postoperatively in the EOI group than PSI group (p < 0.05), The VAS scores were also lower during active movement at PACU, 1, 2, 4, and 8 h postoperatively in the EOI group than PSI group (p < 0.05). Twenty-four-hour fentanyl consumption was lower in the EOI than in the PSI group (505.83 ± 178.56 vs. 880.83 ± 256.78 μg, respectively, p < 0.001). Rescue analgesia was higher in PSI group than EOI group (26/30 vs. 14/30, respectively, p = 0.001).

CONCLUSION

EOI block can be used as a part of multimodal analgesia due to its simplicity and effective postoperative analgesia in LSG.

Effectiveness of erector spinae plane block for rib fracture analgesia: a systematic review protocol

OBJECTIVE

This systematic review will investigate the effectiveness of the ultrasound-guided erector spinae plane block as an analgesic technique for patients with rib fractures compared with all other standard management techniques. Comparisons will be made with both nerve blocks (neuraxial techniques and peripheral nerve blocks) and systemic treatment (with patient-controlled analgesia and/or per required need analgesia for breakthrough pain).

INTRODUCTION

Erector spinae plane block is a well-established rescue analgesia option for patients with rib fractures. The use of ultrasound-guided erector spinae plane block in clinical practice has been largely based on observational data, with recent randomized controlled trials examining it against several other options for analgesic management. This review will compare the erector spinae against all other management techniques used in practice for rib fractures to determine whether this is the most effective analgesic technique.

INCLUSION CRITERIA

The review will include all randomized controlled and pseudo-randomized controlled trials examining ultrasound-guided erector spinae plane block for the analgesic management of traumatic rib fractures. All other study designs will be excluded.

METHODS

MEDLINE (PubMed), Embase (Ovid), CINAHL (EBSCOhost), the Cochrane Central Register of Controlled Trials, the Australian and New Zealand Clinical Trials Registry (ANZCTR), ClinicalTrials.gov, and the ISRCTN registry will be searched to identify all relevant ongoing clinical trials. Study selection, critical appraisal, and data extraction will be performed by 2 independent reviewers. Data will be extracted into software for statistical analysis (including meta-analysis where possible).

REVIEW REGISTRATION

PROSPERO CRD42023414849.

Evaluation of basal rate infusion in intravenous patient-controlled analgesia for post-cesarean section pain management: A randomized pilot study

OBJECTIVE

Administering opioids via intravenous patient-controlled analgesia is a prevalent approach for managing postoperative pain. Nevertheless, due to concerns about opioid-related side effects and the potential for opioid tolerance, there is a growing emphasis on adopting opioid-sparing techniques for postoperative pain management. We aimed to investigate the effect of adding a basal rate infusion in fentanyl-based IVA following a cesarean section (CS).

METHOD

Forty-eight patients, who received pain management through IVA after CS, were assigned randomly into 3 groups based on the background rate setting: Group 0 (0 mcg/hour, n = 16), Group 1 (15 mcg/hour, n = 16), and Group 2 (30 mcg/hour, n = 16). We assessed the impact of the basal infusion rate on opioid consumption and the visual analog scale (VAS) scores during the first 48 hours post-CS and also investigated opioid-induced side effects and the requirement for rescue analgesics in the ward during the first 48 hours after CS.

RESULTS

In the initial 24 hours following CS, fentanyl consumption significantly increased in Group 2 compared with Group 0 and Group 1 (P = .037). At 24 hours, VAS scores both at rest and during movement, tended to decrease, as the basal rate increased; however, no significant differences were observed between the groups (P = .218 and 0.827, respectively). Between the first 24- and 48-hours post-CS, fentanyl consumption showed a marked increase in both Group 1 and Group 2 compared to Group 0 (P < .001). At 48 hours, the VAS scores at rest displayed a trend toward reduction; however, no significant differences between groups were evident (P = .165). Although the incidence of opioid-induced complications was noted, no statistically significant differences were recorded between groups during the initial 24 hours and subsequent 24 to 48 hours period (P = .556 and P = .345, respectively).

CONCLUSION

The inclusion of a basal fentanyl infusion in the IVA protocol did not provide any advantages over an IVA devoid of a basal rate infusion in managing acute pain following CS.

Multivalent Vaccination Strategies Protect against Exposure to Polydrug Opioid and Stimulant Mixtures in Mice and Rats

Illicit drug mixtures containing opioids and stimulants have been responsible for the majority of fatal drug overdoses among occasional users, and those with either opioid use disorder (OUD) or substance use disorder (SUD). As a complementary strategy to current pharmacotherapies, active immunization with conjugate vaccines has been proposed as a viable intervention to treat OUD as well as other SUD for which there are either limited or no treatment options. Vaccination against opioids and stimulants could help address the limitations of current medications (e.g., patient access, compliance, misuse liability, and safety) by providing an additional tool to prevent drug misuse and/or overdoses. However, more research is needed to fully understand the potential benefits and limitations of using vaccines to treat SUD and overdose and to inform us on how to deploy this strategy in the field. Previous reports have shown promise by combining two vaccines into bivalent vaccine formulations to concurrently target multiple drugs. Here, multiple individual candidate monovalent vaccines were incrementally combined in multivalent vaccine formulations to simultaneously target fentanyl, carfentanil, oxycodone, heroin, methamphetamine, and their analogs or metabolites. Bi-, tri-, and quadrivalent vaccine formulations induced the formation of independent serum antibody responses against their respective opioid targets and selectively attenuated the distribution of each individual drug to the brain in mice and rats. Results indicate that a single injection of an admixed multivalent vaccine formulation may be more effective than coinjecting multiple monovalent vaccines at multiple sites. Finally, adding a methamphetamine conjugate vaccine to an quadrivalent opioid vaccine in a pentavalent formulation did not interfere with the production of effective antiopioid IgG antibodies. Multivalent vaccines could provide multifaceted, yet selective, protection against polydrug use and exposure.

Randomized single blind trial to compare the short term post-operative outcome and cost analysis of laparoscopic versus ultrasound guided transversus abdominis plane block in patients undergoing bariatric surgery

INTRODUCTION

Laparoscopic Bariatric surgery despite being minimally invasive can cause moderate to severe pain in the immediate postoperative period. Adequate pain management remains a major challenge. Transversus Abdominis Plane (TAP) block is a regional anesthesia technique which blocks the sensory nerve supply of anterior-lateral abdominal wall.

AIMS AND OBJECTIVES

Primary: evaluate Laparoscopic versus ultrasound (USG)-guided TAP block on immediate post-operative analgesia after undergoing laparoscopic bariatric surgery. Secondary: compare cost effectiveness of Laparoscopic versus ultrasound-guided TAP block after undergoing bariatric surgery.

MATERIALS AND METHODS

Randomized Single blind study undertaken after sample size was calculated by (N) = 2(Zα + Z1-β)2σ2/δ2 which proposed 60 patients in each group. Block randomization was done after excluding redo/revision surgeries and patients were alloted Group I: Laparoscopic-guided TAP block & Group II: USG-guided TAP block. In both groups, Bilaterally, 20 ml (0.25%) bupivacaine was injected immediately after completion of bariatric surgery. SPSS v23 (IBM Corp.) was used for analysis.

RESULTS

Group I (N = 61 53F/8 M) & Group II (N = 60 42F/18 M) were demographically comparable. Group I (3.58 ± 0.67) had significantly lower procedure time compared to Group II (12.47 ± 1.61) (p-Value < 0.001). First rescue analgesia was administered at 7.07 ± 2.61 h in Group I vs 7.21 ± 2.39 h in Group II (p-Value 0.659). In first 24 h rescue analgesic dose requirement in Group I was 1.29 ± 0.53 vs 1.39 ± 0.50 in Group II (p-Value 0.487). VAS scores during rest and movement till 24 h post-operative were statistically similar. Procedural cost was more in group II.

CONCLUSION

Laparoscopic-guided TAP block is a safe and cost-effective approach for postoperative pain management after bariatric surgery and provides similar comparable analgesic effect as the USG-TAP block. Laparoscopic TAP is a surgeon delivered, easy to administer and significantly less time-consuming procedure which is feasible even when an ultrasound machine is not available.

Sleep Disturbances and Disorders in Patients with Knee Osteoarthritis and Total Knee Arthroplasty

➤

There is increasing evidence that patient-reported outcomes following total knee arthroplasty (TKA) are associated with psychosocial factors and pain catastrophizing. Sleep disturbance, pain, and mental health have a complex interaction, which, if unrecognized, can be associated with impaired patient-reported outcomes and dissatisfaction following TKA.

➤

The gold standard of objective sleep assessment is polysomnography, which is not feasible to use routinely for TKA patients. Wearable devices are a validated and less costly alternative.

➤

Subjective sleep measures, such as the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, or Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive test sleep domains, are simple to administer and provide additional insight into sleep disturbance. Although objective and subjective measures do not correlate precisely, they can be informative together.

➤

Sleep disturbances in the elderly population are common and multifactorial in etiology, stemming from the interplay of sleep disorders, medication side effects, and pain. Commonly prescribed medications following TKA as well as postoperative pain can exacerbate underlying sleep disturbances.

➤

Obstructive sleep apnea (OSA) is prevalent in patients seeking TKA. In the setting of OSA, postoperative opioids can cause respiratory depression, resulting in consequences as severe as death. A standardized multimodal pain protocol including anti-inflammatories and gamma-aminobutyric acid (GABA) analogues may allow for decreased reliance on opioids for pain control.

➤

Surgeons should reassure patients that postoperative sleep disturbance is common and transient, collaborate with the patient's primary care doctor to address sleep disturbance, and avoid prescription of pharmaceutical sleep aids.

The onset and severity of acute opioid toxicity in heroin overdose cases: a retrospective cohort study at a supervised injecting facility in Melbourne, Australia

AIM

To differentiate the severity of acute opioid toxicity and describe both the clinical and physiological features associated with heroin overdose in a cohort of witnessed overdose cases.

METHODS

Witnessed heroin overdose cases over a 12-month period (30 June 2018 - 30 June 2019) at the Medically Supervised Injecting Room (MSIR) in Melbourne, Australia were examined. The severity of acute opioid toxicity was classified according to the level of clinical intervention required to manage the overdose cases where an escalating level of care was provided. Heroin overdose cases were classified into one of three graded severity categories and a fourth complicated heroin overdose category.

RESULTS

A total of 1218 heroin overdose cases were identified from 60,693 supervised injecting visits over the study period. On the spectrum of toxicity, 78% (n = 955) of overdose cases were classified as Grade 1 severity, 7% (n = 83) as Grade 2 severity, and 13% (n = 161) as Grade 3 acute opioid toxicity severity cases, as well as 2% (n = 19) classified as complicated heroin overdose cases. The median onset time for heroin overdose cases was 17 min (IQR 11-28 min) from the time the individual was ready to prepare and inject heroin until clinical intervention was initiated.

CONCLUSION

We demonstrated that heroin overdose is a dynamic illness and cases differ in the severity of acute opioid toxicity. The risk of airway occlusion including positional asphyxia was an early and consistent feature across all levels of toxicity, while exaggerated respiratory depression together with exaggerated depression of consciousness was increasingly observed with greater levels of toxicity. We also demonstrated the importance of early intervention in overdose cases, where in a large cohort of heroin overdose cases there were no fatal outcomes, a very low hospitalisation rate and most cases were able to be managed to clinical resolution on-site.

An overview of pain assessment and management

Pain is a distressing, subjective and complex phenomenon that all nurses will encounter in their clinical practice. Effective pain management requires nurses to undertake a structured assessment to identify the probable causes of pain and guide management. Interventions used to reduce pain can be varied and multimodal. This article provides an overview of pain including its definition, classifications, assessment and management. It emphasises the importance of a person-centred approach to care which reflects Margo McCaffery's seminal quote that pain is 'whatever the experiencing person says it is'.

Postoperative Respiratory Events in Surgical Patients Exposed to Opioid Analgesic Shortages Compared to Fully Matched Patients Non-exposed to Shortages

INTRODUCTION

Shortages of opioid analgesics critically disrupt clinical practice and are detrimental to patient safety. There is a dearth of studies assessing the safety implications of drug shortages.

OBJECTIVE

We aimed to assess perioperative opioid analgesic use and related postoperative hypoxemia (oxygen saturation less than 90%) in surgical patients exposed to prescription opioid shortages compared to propensity score-matched patients non-exposed to opioid shortages.

METHODS

We conducted a retrospective study including adult patients who underwent elective surgery at The University of California San Francisco in the period August 2018-December 2019. We conducted a Gamma log-link generalized linear model to assess the effect of shortages on perioperative use of opioids and a weighted logistic regression to assess the likelihood of experiencing postoperative hypoxemia.

RESULTS

There were 1119 patients exposed to opioid shortages and 2787 matched non-exposed patients. After full matching, patients exposed to shortages used a greater mean of morphine milligram equivalents/day (146.94; 95% confidence interval 123.96-174.16) than non-exposed patients (117.92; 95% confidence interval 100.48-138.38; p = 0.0001). The estimated effect was a 1.25 (95% confidence interval 1.12-1.40; p = 0.0001) times greater use of opioids in patients exposed to opioid shortages than non-exposed patients. After full matching, a greater proportion of patients exposed to shortages (19.06%) experienced hypoxemia compared with non-exposed patients (16.91%). In addition, a greater proportion of patients exposed to opioid shortages (1.20%) experienced hypoxemia reversed by intravenous naloxone administration compared with non-exposed patients (0.44%).

CONCLUSIONS

Given the shortage prevalence, reliance on opioid medications, and related risk of respiratory depression, harm prevention measures remain critical to prevent postoperative complications that may compromise patients' safety.

Clinical implications of opioid-induced ventilatory impairment

Opioid-induced ventilatory impairment is the primary mechanism of harm from opioid use. Opioids suppress the activity of the central respiratory centres and are sedating, leading to impairment of alveolar ventilation.Respiratory physiological changes induced with acute opioid use include depression of the hypercapnic ventilatory response and hypoxic ventilatory response. In chronic opioid use a compensatory increase in hypoxic ventilatory response maintains ventilation and contributes to the onset of sleep-disordered breathing patterns of central sleep apnoea and ataxic breathing. Supplemental oxygen use in those at risk of opioid-induced ventilatory impairment requires careful consideration by the clinician to prevent failure to detect hypoventilation, if oximetry is being relied on, and the overriding of hypoxic ventilatory drive. Obstructive sleep apnoea and opioid-induced ventilatory impairment are frequently associated, with this interrelationship being complex and often unpredictable. Monitoring the patient for opioid-induced ventilatory impairment poses challenges in the areas of reliability, avoidance of alarm fatigue, cost, and personnel demands. Many situations remain in which patients cannot be provided effective analgesia without opioids, and for these the clinician requires a comprehensive knowledge of opioid-induced ventilatory impairment.

Opioids in acute pain: Towards getting the right balance

Misuse of prescription opioids forced an inevitable response from authorities to intervene with consequences felt by all.In the Australian community one person will die for approximately every 3600 adults prescribed opioids, while in the hospital setting a postoperative patient managed primarily with opioids, as opposed to epidural analgesia, has an additional risk of death as high as between one in 56 to 477.Opioids maintain a valid role in acute pain management when use is reasoned and with full awareness of the harms and how they are to be avoided, such as in those at risk of ongoing use, the opioid naïve, and when opioid-induced ventilatory impairment may occur.Clinicians managing acute pain can focus on assessing pain versus nociception, strategically apply antinociceptive medications and neural blockade when indicated, assess pain with an emphasis on the degree of bothersomeness and functional impairment and, finally, optimise the use of framing and placebo-enhancing communication to minimise reliance on medications.

Efficacy of laparoscopic transversus abdominis plane block on postoperative pain management and surgery side effects in laparoscopic bariatric surgeries

PURPOSE

Transversus abdominis plane (TAP) block is a new option for reducing postoperative pain. This study investigated the effects of laparoscopic TAP block on postoperative adverse events and analgesia and antiemetics requirements after bariatric surgery.

METHODS

In this randomized clinical trial study, patients were randomly divided into control (N = 20) or TAP block (N = 20) groups. In the TAP block group, the block was performed under direct laparoscopic guidance after surgery and before the removal of trocars.

RESULTS

Fifteen patients (75%) versus four patients (20%) received opioids within the first 6 h in the control and TAP groups, respectively (p-value < 0.001). The cumulative amount of opioids consumed in the 24 and 48 h after surgery was lower in the TAP group (p-value < 0.001). The visual analog scale (VAS) regarding general and wound-specific pain was significantly lower in the TAP group compared to the control group at 6 and 24 h both at rest and in movement. However, there was no significant difference at 48 h postoperatively. The percentages of patients having postoperative nausea and vomiting (PONV), pruritus, and resumption of bowel movement were not significantly different between the two groups at any time (6, 24, and 48 h) postoperatively.

CONCLUSION

Laparoscopic-guided TAP block is a pragmatic, applicable, and minimally invasive regional technique and can be part of effective postoperative pain management in morbidly obese patients undergoing bariatric surgery. Applying it laparoscopically without the need for ultrasound is also useful and effective.

Complete opioid transition to sublingual Buprenorphine after abdominal surgery is associated with significant reductions in opioid requirements, but not reduction in hospital length of stay: a retrospective cohort study

Background

The use of sublingual buprenorphine (SLBup) for acute pain after major abdominal surgery may offer the potential advantages of unique analgesic properties and more reliable absorption during resolving ileus. We hypothesized that complete opioid transition to SLBup rather than oral oxycodone (OOxy) in the early postoperative period after major abdominal surgery would reduce hospital length of stay, and acute pain and total OMEDD (Oral Morphine Equivalent Daily Dose) requirements in the first 24 h from post-parenteral opioid transition.

Methods

We reviewed 146 patients who had undergone elective and emergency abdominal surgery under our quaternary referral centre’s Upper Gastro-Intestinal and Colo-Rectal Surgical Units 6 months before and after the introduction of complete postoperative transition to sublingual buprenorphine, rather than oral oxycodone, in July 2017. Our primary endpoint was 24-hourly post-transition OMEDDs; secondary endpoints were 24-hourly post-transition Mean NRS-11 pain scores on movement (POM) and length of hospital stay (LOS). Univariate analysis and linear multivariate regression analyses were used to quantify effect size and identify surgical, patient & other analgesic factors associated with these outcome measures.

Results

Patients transitioning to SLBup had reduced 24-hourly post-transition OMEDD requirements on postoperative day 2 (POD) (26 mg less, p = 0.04) and NRS-11 POM at POD1 (0.7 NRS-11 units less, p = 0.01). When adjusting for patient, surgical and special analgesic factors, SLBup was associated with a similar reduction in OMEDDs (Unstandardised beta-coefficient -26 mg, p = 0.0001), but not NRS-11 POM (p = 0.47) or hospital LOS (p = 0.16).

Conclusions

Our change of practice from use of OOxy to SLBup as primary transition opioid from patient-controlled analgesia delivered full opioid agonists was associated with a clinically significant decrease in 24-hourly post-parenteral opioid transition OMEDDs and improved NRS-11 POM, but without an association with hospital LOS after major abdominal surgery. Further prospective randomized work is required to confirm these observed associations and impact on other important patient-centred outcomes.

Inpatient Respiratory Arrest Associated With Sedative and Analgesic Medications: Impact of Continuous Monitoring on Patient Mortality and Severe Morbidity

OBJECTIVES

The primary study objective was to investigate the impact of surveillance monitoring (i.e., continuous monitoring optimized for deterioration detection) on mortality and severe morbidity associated with administration of sedative/analgesic medications in the general care setting. A second objective was consideration of the results in the context of previous investigations to establish practice recommendations for this approach to patient safety.

METHODS

Retrospective review of available rescue event and patient safety data from a tertiary care hospital in a rural setting was performed for a 10-year period. Systematic analysis of all adult general care inpatient data followed by chart review for individual patients was used to identify patient death or permanent harm (i.e., ventilator dependency, hypoxic encephalopathy) related to administration of sedative/analgesics.

RESULTS

Of 111,488 patients in units with surveillance monitoring available, none died or were harmed by opioid-induced respiratory depression when surveillance monitoring was in use. One patient died from opioid-induced respiratory depression in a unit where surveillance monitoring was available; however, the patient was not monitored at the time of the adverse event. In unmonitored units (15,209 patients during 29 months of incremental implementation), three patients died from opioid overdose (19.73 deaths per 100,000 at risk patients). The reduced death rate when surveillance monitoring was available (0.0009%) versus not available (0.02%) was significant (P = 0.03).

CONCLUSIONS

For a 10-year period, the rescue system with continuous surveillance monitoring had a profound effect on death from sedative/analgesic administration in the general care setting. This approach to patient safety can help address the risk of sedative/analgesic-related respiratory arrests in hospitals.

Effect of Mobilization on the Day of Surgery After Total Hip Arthroplasty in Elderly, Obese, and Severely Diseased Patients

BACKGROUND

Mobilization on the day of surgery after total hip arthroplasty (THA) is widely used. However, elderly, obese and severely diseased patients are often excluded from early mobilization. Therefore, it was our aim to investigate the effect of mobilization on the day of surgery with focus on these patients.

METHODS

167 patients underwent THA via direct anterior approach. Exclusion criterion was the use of wound drainage. The patients were randomly allocated to two groups. Day 0 group was mobilized 4 hours after surgery, day 1 group the day after surgery. Primary outcome was the time to readiness for discharge (TRD). Secondary outcome was the occurrence of adverse events (vertigo, nausea, vomiting, severe pain) on the day of surgery. Group comparisons were calculated with respect to elderly (age ≥75 years), obese (BMI ≥30 kg/m²) and severely diseased patients (ASA≥3).

RESULTS

TRD was shorter in day 0 group (3.25 vs 3.99 days, P < .01). The rate of adverse events on the day of surgery was similar in both groups (0.28 vs 0.25, P = .73). TRD differences were higher within all subgroups (3.85vs4.81; 3.25vs4.39; 4.08vs5.11days) while the rate of immediate adverse events was reduced (0.15vs0.24; 0.25vs0.3; 0.25vs0.33). Within 90 days 3 patients of group 0 underwent revision surgery, none of group 1 (P = .12).

CONCLUSION

Mobilization on the day of surgery reduces the TRD without increasing the rate of immediate adverse events, regardless of age, BMI and ASA score. Future studies are needed to investigate if early mobility increases the 90-days complication rate.

Safety evaluation of oliceridine for the management of postoperative moderate-to-severe acute pain

INTRODUCTION

Opioids for managing postoperative pain are associated with side effects including opioid-induced respiratory depression (OIRD) and gastrointestinal complications. Opioids induce analgesia via G-protein signaling, while adverse effects are mediated by the β-arrestin pathway. Oliceridine is a biased ligand that preferentially activates G-protein signaling over β-arrestin, theoretically reducing adverse effects. Oliceridine has been approved by the Food and Drug Administration to treat acute pain severe enough to require intravenous opioid analgesics.

AREAS COVERED

Preclinical and clinical trials demonstrate the analgesic efficacy of oliceridine. Available evidence suggests that oliceridine may have a lower risk of OIRD and gastrointestinal complications compared to conventional opioids.

EXPERT OPINION

The analgesic efficacy of oliceridine has been evaluated in several clinical trials. However, safety data were obtained from an open-label observational study and studies assessing adverse effects as secondary outcomes, as post-hoc analyses, or from retrospective studies. These may be affected by gaps in detecting adverse events, heterogeneity in the original studies, and the limitations of retrospective studies. Prospective trials examining the safety of oliceridine versus conventional opioids are needed. Studies are also needed to assess the safety and efficacy of oliceridine in obstetric and pediatric populations, and in the context of multimodal analgesia and Enhanced Recovery after Surgery protocols.

Mortality and concurrent use of opioids and hypnotics in older patients: A retrospective cohort study

BACKGROUND

Benzodiazepine hypnotics and the related nonbenzodiazepine hypnotics (z-drugs) are among the most frequently prescribed medications for older adults. Both can depress respiration, which could have fatal cardiorespiratory effects, particularly among patients with concurrent opioid use. Trazodone, frequently prescribed in low doses for insomnia, has minimal respiratory effects, and, consequently, may be a safer hypnotic for older patients. Thus, for patients beginning treatment with benzodiazepine hypnotics or z-drugs, we compared deaths during periods of current hypnotic use, without or with concurrent opioids, to those for comparable patients receiving trazodone in doses up to 100 mg.

METHODS AND FINDINGS

The retrospective cohort study in the United States included 400,924 Medicare beneficiaries 65 years of age or older without severe illness or evidence of substance use disorder initiating study hypnotic therapy from January 2014 through September 2015. Study endpoints were out-of-hospital (primary) and total mortality. Hazard ratios (HRs) were adjusted for demographic characteristics, psychiatric and neurologic disorders, cardiovascular and renal conditions, respiratory diseases, pain-related diagnoses and medications, measures of frailty, and medical care utilization in a time-dependent propensity score-stratified analysis. Patients without concurrent opioids had 32,388 person-years of current use, 260 (8.0/1,000 person-years) out-of-hospital and 418 (12.9/1,000) total deaths for benzodiazepines; 26,497 person-years,150 (5.7/1,000) out-of-hospital and 227 (8.6/1,000) total deaths for z-drugs; and 16,177 person-years,156 (9.6/1,000) out-of-hospital and 256 (15.8/1,000) total deaths for trazodone. Out-of-hospital and total mortality for benzodiazepines (respective HRs: 0.99 [95% confidence interval, 0.81 to 1.22, p = 0.954] and 0.95 [0.82 to 1.14, p = 0.513] and z-drugs (HRs: 0.96 [0.76 to 1.23], p = 0.767 and 0.87 [0.72 to 1.05], p = 0.153) did not differ significantly from that for trazodone. Patients with concurrent opioids had 4,278 person-years of current use, 90 (21.0/1,000) out-of-hospital and 127 (29.7/1,000) total deaths for benzodiazepines; 3,541 person-years, 40 (11.3/1,000) out-of-hospital and 64 (18.1/1,000) total deaths for z-drugs; and 2,347 person-years, 19 (8.1/1,000) out-of-hospital and 36 (15.3/1,000) total deaths for trazodone. Out-of-hospital and total mortality for benzodiazepines (HRs: 3.02 [1.83 to 4.97], p < 0.001 and 2.21 [1.52 to 3.20], p < 0.001) and z-drugs (HRs: 1.98 [1.14 to 3.44], p = 0.015 and 1.65 [1.09 to 2.49], p = 0.018) were significantly increased relative to trazodone; findings were similar with exclusion of overdose deaths or restriction to those with cardiovascular causes. Limitations included composition of the study cohort and potential confounding by unmeasured variables.

CONCLUSIONS

In US Medicare beneficiaries 65 years of age or older without concurrent opioids who initiated treatment with benzodiazepine hypnotics, z-drugs, or low-dose trazodone, study hypnotics were not associated with mortality. With concurrent opioids, benzodiazepines and z-drugs were associated with increased out-of-hospital and total mortality. These findings indicate that the dangers of benzodiazepine-opioid coadministration go beyond the documented association with overdose death and suggest that in combination with opioids, the z-drugs may be more hazardous than previously thought.

Obesity and Obesity Hypoventilation, Sleep Hypoventilation, and Postoperative Respiratory Failure

Obesity hypoventilation syndrome (OHS) is considered as a diagnosis in obese patients (body mass index [BMI] ≥30 kg/m2) who also have sleep-disordered breathing and awake diurnal hypercapnia in the absence of other causes of hypoventilation. Patients with OHS have a higher burden of medical comorbidities as compared to those with obstructive sleep apnea (OSA). This places patients with OHS at higher risk for adverse postoperative events. Obese patients and those with OSA undergoing elective noncardiac surgery are not routinely screened for OHS. Screening for OHS would require additional preoperative evaluation of morbidly obese patients with severe OSA and suspicion of hypoventilation or resting hypoxemia. Cautious selection of the type of anesthesia, use of apneic oxygenation with high-flow nasal cannula during laryngoscopy, better monitoring in the postanesthesia care unit (PACU) can help minimize adverse perioperative events. Among other risk-reduction strategies are proper patient positioning, especially during intubation and extubation, multimodal analgesia, and cautious use of postoperative supplemental oxygen.

Opioid-Induced In-Hospital Deaths: A 10-Year Review of Australian Coroners' Cases Exploring Similarities and Lessons Learnt

Although opioids are the cornerstone of moderate-to-severe acute pain management they are appropriately recognised as high-risk medicines. Patient and health service delivery factors can contribute to an increased risk of death associated with excessive sedation and respiratory impairment. Despite increasing awareness of opioid-induced ventilation impairment (OIVI), no reliable method consistently identifies individual characteristics and factors that increase mortality risk due to respiratory depression events. This study assessed similarities in available coronial inquest cases reviewing opioid-related deaths in Australian hospitals from 2010 to 2020. Cases included for review were in-hospital deaths that identified patient factors, clinical errors and service delivery factors that resulted in opioid therapy contributing to the death. Of the 2879 coroner’s inquest reports reviewed across six Australian states, 15 met the criteria for inclusion. Coroner’s inquest reports were analysed qualitatively to identify common themes, contributing patient and service delivery factors and recommendations. Descriptive statistics were used to summarise shared features between cases. All cases included had at least one, but often more, service delivery factors contributing to the death, including insufficient observations, prescribing/administration error, poor escalation and reduced communication. Wider awareness of the individual characteristics that pose increased risk of OIVI, greater uptake of formal, evidence-based pain management guidelines and improved documentation and observations may reduce OIVI mortality rates.

Oliceridine: A Novel Drug for the Management of Moderate to Severe Acute Pain - A Review of Current Evidence

Optimal pain relief requires a balance between adequate analgesia and risk of adverse effects. Opioids remain the cornerstone for managing moderate to severe pain, but are associated with opioid-induced respiratory depression (OIRD) and gastrointestinal complications. Opioids exert their analgesic effects predominantly via G-protein signaling, however, adverse effects including OIRD are mediated by the β-arrestin pathway. Oliceridine is the first of a new class of biased opioid agonists that preferentially activate G-protein signaling over β-arrestin, which would theoretically improve analgesia and reduce the risk of adverse effects. Oliceridine is approved by the Food and Drug Administration (FDA) for the treatment of moderate to severe acute pain. The efficacy of Oliceridine was mainly established in two randomized controlled Phase III clinical trials of patients experiencing moderate to severe pain after bunionectomy (APOLLO-1) and abdominoplasty (APOLLO-2). The results of the APOLLO studies demonstrate that Oliceridine, when administered via patient-controlled analgesia (PCA) demand boluses of 0.35mg and 0.5mg, provides superior analgesia compared to placebo, and is equianalgesic to PCA morphine 1mg demand boluses, without significant difference in the incidence of respiratory complications. In a more pragmatic trial of surgical and non-surgical patients, the ATHENA observational cohort study reported rapid onset of analgesia with Oliceridine given with or without multimodal analgesia. However, these studies were designed to evaluate analgesic efficacy, and it is still uncertain if Oliceridine has a better safety profile than conventional opioids. Although several post hoc analyses of pooled data from the APOLLO and ATHENA trials reported that Oliceridine was associated with lower OIRD and gastrointestinal complications compared to morphine, prospective studies are needed to elucidate if biased agonists such as Oliceridine reduce the risk of adverse effects compared to conventional opioids.

An international multidisciplinary consensus statement on the prevention of opioid-related harm in adult surgical patients

This international multidisciplinary consensus statement was developed to provide balanced guidance on the safe peri-operative use of opioids in adults. An international panel of healthcare professionals evaluated the literature relating to postoperative opioid-related harm, including persistent postoperative opioid use; opioid-induced ventilatory impairment; non-medical opioid use; opioid diversion and dependence; and driving under the influence of prescription opioids. Recommended strategies to reduce harm include pre-operative assessment of the risk of persistent postoperative opioid use; use of an assessment of patient function rather than unidimensional pain scores alone to guide adequacy of analgesia; avoidance of long-acting (modified-release and transdermal patches) opioid formulations and combination analgesics; limiting the number of tablets prescribed at discharge; providing deprescribing advice; avoidance of automatic prescription refills; safe disposal of unused medicines; reducing the risk of opioid diversion; and better education of healthcare professionals, patients and carers. This consensus statement provides a framework for better prescribing practices that could help reduce the risk of postoperative opioid-related harm in adults.

Respiratory depression and analgesia by opioid drugs in freely behaving larval zebrafish

An opioid epidemic is spreading in North America with millions of opioid overdoses annually. Opioid drugs, like fentanyl, target the mu opioid receptor system and induce potentially lethal respiratory depression. The challenge in opioid research is to find a safe pain therapy with analgesic properties but no respiratory depression. Current discoveries are limited by lack of amenable animal models to screen candidate drugs. Zebrafish (Danio rerio) is an emerging animal model with high reproduction and fast development, which shares remarkable similarity in their physiology and genome to mammals. However, it is unknown whether zebrafish possesses similar opioid system, respiratory and analgesic responses to opioids than mammals. In freely-behaving larval zebrafish, fentanyl depresses the rate of respiratory mandible movements and induces analgesia, effects reversed by μ-opioid receptor antagonists. Zebrafish presents evolutionary conserved mechanisms of action of opioid drugs, also found in mammals, and constitute amenable models for phenotype-based drug discovery.

When it comes to treating severe pain, a doctor’s arsenal is somewhat limited: synthetic or natural opioids such as morphine, fentanyl or oxycodone are often one of the only options available to relieve patients. Yet these compounds can make breathing slower and shallower, quickly depriving the body of oxygen and causing death. This lethal side-effect is particularly devastating as opioids misuse has reached dangerously high levels in the United States, creating an ‘opioid epidemic’ which has claimed the lives of over 80,000 Americans in 2020. It is therefore crucial to find safer drugs that do not have this effect on breathing, but this research has been slowed down by the lack of animal models in which to study the effect of new compounds.

Zebrafish are small freshwater fish that reproduce and develop fast, yet they are also remarkably genetically similar to mammals and feature a complex nervous system. However, it is not known whether the effect of opioids on zebrafish is comparable to mammals, and therefore whether these animals can be used to test new drugs for pain relief.

To investigate this question, Zaig et al. exposed zebrafish larvae to fentanyl, showing that the fish then exhibited slower lower jaw movements – a sign of decreased breathing. The fish also could also tolerate a painful stimulus for longer, suggesting that this opioid does reduce pain in the animals. Together, these results point towards zebrafish and mammals sharing similar opioid responses, demonstrating that the fish could be used to test potential pain medications. The methods Zaig et al. have developed to establish these results could be harnessed to quickly assess large numbers of drug compounds, as well as decipher how pain emerges and can be stopped.

Perioperative Care and Medication-related Hypoventilation

Cumulative evidence supports the association of adverse postoperative outcomes with obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). Although current guidelines recommend preoperative screening for OSA and OHS, the best perioperative management pathways remain unknown. Interventions attempting to prevent complications in the postoperative period largely are consensus based and focused on enhanced monitoring, conservative measures, and specific OSA therapies, such as positive airway pressure. Until further research is available to improve the quality and strength of these recommendations, patients with known or suspected OSA and OHS should be considered at higher risk for perioperative cardiopulmonary complications.

A preliminary assessment of vital-signs-integrated patient-assisted intravenous opioid analgesia (VPIA) for postsurgical pain

Background

We developed a Vital-signs-integrated Patient-assisted Intravenous opioid Analgesia (VPIA) analgesic infusion pump, a closed-loop vital signs monitoring and drug delivery system which embodied in a novel algorithm that took into account patients’ vital signs (oxygen saturation, heart rate). The system aimed to allow responsive titration of personalized pain relief to optimize pain relief and reduce the risk of respiratory depression. Moreover, the system would be important to enable continuous monitoring of patients during delivery of opioid analgesia.

Methods

Nineteen patients who underwent elective gynecological surgery with postoperative patient controlled analgesia (PCA) with morphine were recruited. The subjects were followed up from their admission to the recovery room/ ward for at least 24 h until assessment of patient satisfaction on the VPIA analgesic infusion pump.

Results

The primary outcome measure of incidence of oxygen desaturation showed all patients had at least one episode of oxygen desaturation (< 95%) during the study period. Only 6 (31.6%) patients had oxygen desaturation that persisted for more than 5 min. The median percentage time spent during treatment that oxygen saturation fell below 95% was 1.9%. Fourteen (73.7%) out of 19 patients encountered safety pause, due to transient oxygen desaturation or bradycardia. The patients’ median [IQR] pain scores at rest and at movement after post-op 24 h were 0.0 [2.0] and 3.0 [2.0], respectively. The average morphine consumption in the first 24 h was 12.5 ± 7.1 mg. All patients were satisfied with their experience with the VPIA analgesic infusion pump.

Conclusions

The use of VPIA analgesic infusion pump, when integrated with continuous vital signs monitor and variable lockout algorithm, was able to provide pain relief with good patient satisfaction.

Trial registration

This study was registered on clinicaltrials.gov registry (NCT02804022) on 28 Feb 2016.

Risk factors for severe opioid-induced respiratory depression in hospitalized adults: A case-control study

Background: Opioids are commonly prescribed to hospitalized adults to promote adequate pain relief, yet they can cause potentially fatal respiratory depression.

Aim: The aim of this study was to examine the risk factors for the development of severe opioid-induced respiratory depression (OIRD) in hospitalized adults to ensure adequate monitoring of high-risk patients.

Methods: A retrospective case–control study was conducted using data from the medical records of a university-affiliated hospital in Canada. Cases were eligible if they were adults (≥18 years old) and received opioid analgesia within 24 h of naloxone administration for respiratory depression. Controls had the same eligibility criteria, except for respiratory depression and naloxone administration. The case–control ratio was 1:1, and they were matched based on sex, type of unit, opioid molecule and the presence/absence of medication errors.

Results: A total of 133 cases and 133 controls were included. Following cumulative risk factor analysis, renal failure (odds ratio [OR] = 2.176, 95% confidence interval [CI], 1.021–4.640, P = 0.044), the first 24 h of opioid administration (OR = 1.899, 95% CI, 1.090–3.309, P = 0.024), concomitant central nervous system (CNS) depressants (OR = 1.785, 95% CI, 1.023–3.113, P = 0.041), and increasing age (OR = 1.019, 95% CI, 1.002–1.035, P = 0.028) were positively associated with severe OIRD.

Conclusions: Some adult hospitalized patients were at higher risk of experiencing severe OIRD, such as those with renal failure, those in their first 24 h of opioid administration, those receiving CNS depressants in addition to opioids, and those with an advanced age. These results will assist with the screening of patients at higher risk for severe OIRD, which is key to implementing appropriate monitoring and enhancing the safety of opioid use in hospital settings.

Alternating Current Iontophoresis for Control of Postoperative Pain

Control of early postoperative pain entails the use of various medications including acetaminophen, nonsteroidal anti-inflammatory drugs, selective cyclooxygenase-2 inhibitors, tramadol, and opioids. However, these medications should be carefully administered in patients with aspirin-exacerbated respiratory disease because some medications may trigger adverse reactions after maxillofacial surgeries. The goal of postoperative pain control in patients with aspirin-exacerbated respiratory disease is to eliminate pain without complications. Local anesthesia is an efficient tool for the control of postoperative pain after maxillofacial surgeries. We utilized a transdermal drug delivery system, iontophoresis by alternating current, in order to develop an alternative technique for administering local anesthetic to control postoperative pain in 2 patients with aspirin-exacerbated respiratory disease. A visual analogue scale was used to objectively measure the severity of pain. A 55-year-old woman who underwent mandibular wisdom tooth extraction and an 18-year-old woman who underwent sagittal split ramus osteotomy of the mandible both complained of pain multiple times. After application of iontophoresis, the visual analogue scale score was reduced to zero and postoperative pain could be controlled. There were no adverse events such as bronchospasm or skin irritation after the application of iontophoresis by alternating current.

Increased Pain Sensitivity in Obese Patients After Lung Cancer Surgery

Background: Obesity and cancer are recognized worldwide health threats. While there is no reported causal relationship, the increasing frequency of both conditions results in a higher incidence of obese patients who are being treated for cancer. Physiological data indicate that there is a relationship between obesity and susceptibility to pain; however, currently, there are no specific pharmacological interventions.

Objective: To evaluate the self-reported intensity of postoperative pain in obese and nonobese lung cancer who receive either thoracotomy or video-assisted thoracic surgery (VATS) surgical therapy.

Material and Methods: In 50 obese [mean body mass index (BMI) of 34.1 ± 3.2 kg/m²] and 62 nonobese (mean BMI of 24.9 ± 3 kg/m²) lung cancer patients, the intensity of pain was estimated every 4 h using a visual analog scale (VAS, 0 indicating no pain and 10 indicating “worst imaginable pain”) beginning shortly after surgery (Day O) and continuing until the day of discharge (Day D).

Results: The self-reported pain was more severe in obese than in nonobese patients, both at the time of the operation [Day O (4.5 ± 1.2 vs 3.4 ± 1.1; p < 0.0001)] and at the day of discharge [Day D (3.9 ± 1.4 vs 2.6 ± 0.9, p < 0.0001)]. This finding was consistent both in the patients after thoracotomy and after video-assisted thoracic surgery (VATS, p < 0.0001). The patients with severe pain shortly after surgery (VAS score >4) had significantly higher BMI (31.8 ± 5.6 kg/m²vs 28.8 ± 5.2 kg/m², p < 0.01) and were hospitalized longer than the remaining patients (13.0 ± 13.6 days vs 9.5 ± 3.6 days, p < 0.05).

Conclusion: The reported perception of pain in obese lung cancer patients is greater than in nonobese patients undergoing the same thoracic surgery. In obese patients, severe pain persisted longer. Pain management is an important consideration in the postoperative care of lung cancer patients, even more so with obese patients.

Neonatal Respiratory Support on Transport

Respiratory support is frequently required during neonatal transport. This review identifies the various modalities of respiratory support available during neonatal transport and their appropriate clinical uses. The respiratory equipment required during neonatal transport and appropriate safety checks are also reviewed. In addition, we discuss potential respiratory emergencies and how to respond to them to decrease the risk of complications during transport and improve health outcomes.

Postoperative Pain Assessment Model Based on Pulse Contour Characteristics Analysis

This study aims to develop a new postoperative pain assessment model based on pulse contour analysis and to evaluate its effectiveness in postoperative pain assessment. We derived candidate features from photoplethysmography (PPG) and developed an assessment model based on multiple logistic regressions with a combination of features. This study also includes investigations into the optimal unit of analysis and number of features. For model development, PPGs obtained from 78 surgical patients with a six-min duration in pre- and post-operation conditions, including a training set of 56 pairs and a test set of 22 pairs, were used. We tested models with 5, 10, 20, 30, 40, 50, 60, 70, and 80 beats as an analysis unit, and with 1 to 8 of features for optimization, then determined 20 beats and three features to be the simplest optimal unit of analysis and number of features, respectively. The selected features were RMSSD-ACV_onset/ACA_bl, AV-A_sys/A_total, and SD-RS, where RMSSD-ACV_onset/ACA_bl is the root mean square of the successive difference of the ratio of pulse onset amplitude to the pulse onset-to-peak amplitude, AV-A_sys/A_total is the average value of a normalized systolic area of a pulse with a total pulse area, and SD-RS is the standard deviation of a rising slope of a pulse. The accuracy (AC) and the area under the curve (AUC) of the proposed model were 0.793 and 0.872 in the development set (N = 56), respectively, which were superior to those of SPI (AC: 0.643, AUC: 0.716) and ANI (AC: 0.633 AUC: 0.671). In the test set (N = 22), the AC and AUC of the proposed model were 0.712 and 0.808, respectively, which were superior to those of SPI (AC: 0.640, AUC: 0.709) and ANI (AC: 0.640, AUC: 0.680).

Challenges with take-home naloxone in reducing heroin mortality: a review of fatal heroin overdose cases in Victoria, Australia

AIM

Take-home naloxone (THN) programs have been implemented in order to reduce the number of heroin-overdose deaths. Because of recent legislative changes in Australia, there is a provision for a greater distribution of naloxone in the community, however, the potential impact of these changes for reduced heroin mortality remains unclear. The aim of this study was to examine the characteristics of the entire cohort of fatal heroin overdose cases and assess whether there was an opportunity for bystander intervention had naloxone been available at the location and time of each of the fatal overdose events to potentially avert the fatal outcome in these cases.

METHODS

The circumstances related to the fatal overdose event for the cohort of heroin-overdose deaths in the state of Victoria, Australia between 1 January 2012 and 31 December 2013 were investigated. Coronial data were investigated for all cases and data linkage was performed to additionally investigate the Emergency Medical Services information about the circumstances of the fatal heroin overdose event for each of the decedents.

RESULTS AND DISCUSSION

There were 235 fatal heroin overdose cases identified over the study period. Data revealed that the majority of fatal heroin overdose cases occurred at a private residence (n = 186, 79%) and where the decedent was also alone at the time of the fatal overdose event (n = 192, 83%). There were only 38 cases (17%) where the decedent was with someone else or there was a witness to the overdose event, and in half of these cases the witness was significantly impaired, incapacitated or asleep at the time of the fatal heroin overdose. There were 19 fatal heroin overdose cases (8%) identified where there was the potential for appropriate and timely intervention by a bystander or witness.

CONCLUSION

This study demonstrated that THN introduction alone could have led to a very modest reduction in the number of fatal heroin overdose cases over the study period. A lack of supervision or a witness to provide meaningful and timely intervention was evident in most of the fatal heroin overdose cases.

Pain and sleep : A bidirectional relationship

Disturbed sleep and persistent pain are common in old people. Persistent pain has a well proven impact on sleep but the relationship between both phenomena is bidirectional since disturbed sleep affects pain perception by lowering the pain threshold. An optimal disease management takes both phenomena into account.

Postoperative Pain Assessment Indices Based on Photoplethysmography Waveform Analysis

The purpose of this study was to derive parameters that might reflect postoperative pain from photoplethysmography (PPG) and verify the derived parameters in postoperative pain assessment. We obtained preoperative and postoperative PPG and 100-mm visual analog scale (VAS) from 65 surgical patients and extracted a total of 51 PPG morphology-based parameters and their normalized parameters from these PPGs obtained. Pain discrimination performances of these derived parameters were assessed by statistical analyses, including Wilcoxon signed rank test with Bonferroni correction, classification accuracy based on logistic regression, and 4-fold cross validation. After comparing these parameters derived from PPG in pre- and post-operative conditions, statistically significant difference was found in 36 of the 51 parameters. Using logistic classification, dynamic between-pulse parameters such as normalized systolic amplitude variation and normalized diastolic amplitude variation showed better pain classification performance than the static within-pulse parameters. VAS score was 0 in every pre-operation condition, but >60 VAS was observed in the post-operative condition. Systolic peak amplitude variation normalized by PPG AC amplitude showed the best performance in classifying post-operative pain, with accuracy, sensitivity, specificity, and positive predictivity values of 79.5, 74.0, 86.0, and 84.5%, respectively. These results are superior to those of the surgical pleth index (SPI, GE Healthcare, Chicago, IL, United States) at 65.9, 65.9, 66.5, and 66.5%, respectively.

Spectrum of postoperative complications in pulmonary hypertension and obesity hypoventilation syndrome

PURPOSE OF REVIEW

The purpose of this review is to identify chronic pulmonary conditions which may often not be recognized preoperatively especially before elective noncardiac surgery and which carry the highest risk of perioperative morbidity and mortality.

RECENT FINDINGS

This review discusses some of the most recent studies that highlight the perioperative complications, and their prevention and management strategies.

SUMMARY

Pulmonary hypertension is a well recognized risk factor for postoperative complications after cardiac surgery but the literature surrounding noncardiac surgery is sparse. Pulmonary hypertension was only recently classified as an independent risk factor for postoperative complications in the American Heart Association/American College of Cardiology Foundation Practice Guideline for noncardiac surgery. Spinal anesthesia should be avoided in most surgeries on patients with pulmonary hypertension because of it's rapid sympatholytic effects. The presence of significant right ventricle dysfunction and marked hypoxemia should prompt re-evaluation of the need for elective surgery. Obesity hypoventilation syndrome is even harder to recognize preoperatively as arterial blood gases are generally not obtained prior to elective noncardiac surgery. Amongst patients with obstructive sleep apnea this group of patients carries much higher risk of postoperative respiratory and congestive heart failure.

Effects of morphine on respiratory load detection, load magnitude perception, and tactile sensation in obstructive sleep apnea

Pharyngeal and respiratory sensation is impaired in obstructive sleep apnea (OSA). Opioids may further diminish respiratory sensation. Thus protective pharyngeal neuromuscular and arousal responses to airway occlusion that rely on respiratory sensation could be impaired with opioids to worsen OSA severity. However, little is known about the effects of opioids on upper airway and respiratory sensation in people with OSA. This study was designed to determine the effects of 40 mg of MS-Contin on tactile sensation, respiratory load detection, and respiratory magnitude perception in people with OSA during wakefulness. A double-blind, randomized, crossover design (1 wk washout) was used. Twenty-one men with untreated OSA (apnea/hypopnea index = 26 ± 17 events/h) recruited from a larger clinical study completed the protocol. Tactile sensation using von Frey filaments on the back of the hand, internal mucosa of the cheek, uvula, and posterior pharyngeal wall were not different between placebo and morphine [e.g., median (interquartile range) posterior wall = 0.16 (0.16, 0.4) vs. 0.4 (0.14, 1.8) g, P = 0.261]. Similarly, compared with placebo, morphine did not alter respiratory load detection thresholds for nadir mask pressure detected = −2.05 (−3.37, −1.55) vs. −2.19 (−3.36, −1.41) cmH2O, P = 0.767], or respiratory load magnitude perception [mean ± SD Borg scores during a 5 resistive load (range: 5–126 cmH2O·l−1·s−1) protocol = 4.5 ± 1.6 vs. 4.2 ± 1.2, P = 0.347] but did reduce minute ventilation during quiet breathing (11.4 ± 3.3 vs. 10.7 ± 2.6 l/min, P < 0.01). These findings indicate that 40 mg of MS-Contin does not systematically impair tactile or respiratory sensation in men with mild to moderate, untreated OSA. This suggests that altered respiratory sensation to acute mechanical stimuli is not likely to be a mechanism that contributes to worsening of OSA with a moderate dose of morphine.

NEW & NOTEWORTHY Forty milligrams of MS-Contin does not alter upper airway tactile sensation, respiratory load detection thresholds, or respiratory load magnitude perception in people with obstructive sleep apnea but does decrease breathing compared with placebo during wakefulness. Despite increasing concerns of harm with opioids, the current findings suggest that impaired respiratory sensation to acute mechanical stimuli with this dose of MS-Contin is unlikely to be a direct mechanism contributing to worsening sleep apnea severity in people with mild-to-moderate disease.

The impact of opioid analgesic prescription uptake on the costs of recovery from injury: Evidence from compensable orthopaedic road trauma patients

Long-term opioid prescribing after compensable orthopaedic injury may contribute to the 'long right tail' in the cost of recovery. The aim of this study was to estimate the effect of prescription opioid uptake on injury compensation cost, using orthopaedic road traffic injury claims data from Victoria, Australia. We used a maximum likelihood estimation that accounts for potential endogeneity associated with opioid uptake, utilizing information on the doctor's differential propensity to prescribe opioids when treating other compensable injury patients. Our results suggest that opioid recipients incurred significantly greater hospital costs, income compensation payments, and medical and paramedical expenses. Overall, income compensation was the primary driver of the claim cost difference between opioid recipients and non-recipients. The findings imply that there is scope to impose restrictions on long-term opioid usage, and to encourage the use of alternative pain relief medicines.