Perioperative management of patients on glucagon-like peptide-1 receptor agonists

PURPOSE OF REVIEW

To summarize the mechanism of action, clinical outcomes, and perioperative implications of glucagon-like peptide-1 receptor agonists (GLP-1-RAs). Specifically, this review focuses on the available literature surrounding complications (primarily, bronchoaspiration) and current recommendations, as well as knowledge gaps and future research directions on the perioperative management of GLP-1-RAs.

RECENT FINDINGS

GLP-1-RAs are known to delay gastric emptying. Accordingly, recent case reports and retrospective observational studies, while anecdotal, suggest that the perioperative use of GLP-1-RAs may increase the risk of bronchoaspiration despite fasting intervals that comply with (and often exceed) current guidelines. As a result, guidelines and safety bulletins have been published by several Anesthesiology Societies.

SUMMARY

While rapidly emerging evidence suggests that perioperative GLP-1-RAs use is associated with delayed gastric emptying and increased risk of bronchoaspiration (particularly in patients undergoing general anesthesia and/or deep sedation), high-quality studies are needed to provide definitive answers with respect to the safety and duration of preoperative drug cessation, and optimal fasting intervals according to the specific GLP-1-RA agent, the dose/duration of administration, and patient-specific factors. Meanwhile, clinicians must be aware of the potential risks associated with the perioperative use of GLP-1-RAs and follow the recommendations put forth by their respective Anesthesiology Societies.

Competencies for proficiency in basic point-of-care ultrasound in anesthesiology: national expert recommendations using Delphi methodology

PURPOSE

Point-of-care ultrasound (POCUS) allows for rapid bedside assessment and guidance of patient care. Recently, POCUS was included as a mandatory component of Canadian anesthesiology training; however, there is no national consensus regarding the competencies to guide curriculum development. We therefore aimed to define national residency competencies for basic perioperative POCUS proficiency.

METHODS

We adopted a Delphi process to delineate relevant POCUS competencies whereby we circulated an online survey to academic anesthesiologists identified as POCUS leads/experts (n = 25) at all 17 Canadian anesthesiology residency programs. After reviewing a list of competencies derived from the Royal College of Physicians and Surgeons of Canada's National Curriculum, we asked participants to accept, refine, delete, or add competencies. Three rounds were completed between 2022 and 2023. We discarded items with < 50% agreement, revised those with 50-79% agreement based upon feedback provided, and maintained unrevised those items with ≥ 80% agreement.

RESULTS

We initially identified and circulated (Round 1) 74 competencies across 19 clinical domains (e.g., basics of ultrasound [equipment, nomenclature, clinical governance, physics]; cardiac [left ventricle, right ventricle, valve assessment, pericardial effusion, intravascular volume status] and lung ultrasound anatomy, image acquisition, and image interpretation; and clinical applications [monitoring and serial assessments, persistent hypotension, respiratory distress, cardiac arrest]). After three Delphi rounds (and 100% response rate maintained), panellists ultimately agreed upon 75 competencies.

CONCLUSION

Through national expert consensus, this study identified POCUS competencies suitable for curriculum development and assessment in perioperative anesthesiology. Next steps include designing and piloting a POCUS curriculum and assessment tool(s) based upon these nationally defined competencies.

Analgesia for rib fractures: a narrative review

PURPOSE

Rib fracture(s) is a common and painful injury often associated with significant morbidity (e.g., respiratory complications) and high mortality rates, especially in the elderly. Risk stratification and prompt implementation of analgesic pathways using a multimodal analgesia approach comprise a primary endpoint of care to reduce morbidity and mortality associated with rib fractures. This narrative review aims to describe the most recent evidence and care pathways currently available, including risk stratification tools and pharmacologic and regional analgesic blocks frequently used as part of the broadly recommended multimodal analgesic approach.

SOURCE

Available literature was searched using PubMed and Embase databases for each topic addressed herein and reviewed by content experts.

PRINCIPAL FINDINGS

Four risk stratification tools were identified, with the Study of the Management of Blunt Chest Wall Trauma score as most predictive. Current evidence on pharmacologic (i.e., acetaminophen, nonsteroidal anti-inflammatory drugs, gabapentinoids, ketamine, lidocaine, and dexmedetomidine) and regional analgesia (i.e., thoracic epidural analgesia, thoracic paravertebral block, erector spinae plane block, and serratus anterior plane block) techniques was reviewed, as was the pathophysiology of rib fracture(s) and its associated complications, including the development of chronic pain and disabilities.

CONCLUSION

Rib fracture(s) continues to be a serious diagnosis, with high rates of mortality, development of chronic pain, and disability. A multidisciplinary approach to management, combined with appropriate analgesia and adherence to care bundles/protocols, has been shown to decrease morbidity and mortality. Most of the risk-stratifying care pathways identified perform poorly in predicting mortality and complications after rib fracture(s).

Dobutamine and Goal-Directed Fluid Therapy for Improving Tissue Oxygenation in Deep Inferior Epigastric Perforator (DIEP) Flap Breast Reconstruction Surgery: Protocol for a Randomized Controlled Trial

BACKGROUND

Breast reconstruction is an integral part of breast cancer care. There are 2 main types of breast reconstruction: alloplastic (using implants) and autologous (using the patient's own tissue). The latter creates a more natural breast mound and avoids the long-term need for surgical revision-more often associated with implant-based surgery. The deep inferior epigastric perforator (DIEP) flap is considered the gold standard approach in autologous breast reconstruction. However, complications do occur with DIEP flap surgery and can stem from poor flap tissue perfusion/oxygenation. Hence, the development of strategies to enhance flap perfusion (eg, goal-directed perioperative fluid therapy) is essential. Current perioperative fluid therapy is traditionally guided by subjective criteria, which leads to wide variations in clinical practice.

OBJECTIVE

The main objective of this trial is to determine whether the use of minimally invasive cardiac output (CO) monitoring for guiding intravenous fluid administration, combined with low-dose dobutamine infusion (via a treatment algorithm), will increase tissue oxygenation in patients undergoing DIEP flap surgery.

METHODS

With appropriate institutional ethics board and Health Canada approval, patients undergoing DIEP flap surgery are randomly assigned to receive CO monitoring for the guidance of intraoperative fluid therapy in addition to a low-dose dobutamine infusion (which potentially improves flap oxygenation) versus the current standard of care. The primary outcome is tissue oxygenation measured via near-infrared spectroscopy at the perfusion zone furthest from the perforator vessels 45 minutes after vascular reanastomosis of the DIEP flap. Low dose (2.5 μg/kg/hr) dobutamine infusion continues for up to 4 hours postoperatively, provided there are no associated complications (ie, persistent tachycardia). Flap oxygenation, hemodynamic parameters, and any medication-associated side effects/complications are monitored for up to 48 hours postoperatively. Complications, rehospitalizations, and patient satisfaction are also collected until 30 days postoperatively.

RESULTS

Funding and regulatory approvals were obtained in 2019, but the study recruitment was interrupted by the COVID-19 pandemic. As of October 4, 2023, 34 participants have been recruited. Because of the significant delays associated with the pandemic, the expected completion date was extended. We expect the study to be completed and ready for potential news release (as appropriate) and publication by July 2024. No patients have suffered any adverse effects/complications from participating in this study, and none have been lost to follow-up.

CONCLUSIONS

CO-directed fluid therapy in combination with a low-dose dobutamine infusion via a treatment algorithm has the potential to improve DIEP flap tissue oxygenation and reduce complications following DIEP flap breast reconstruction surgery. However, given that the investigators remain blinded to group randomization, no comment can be made regarding the efficacy of this intervention for improving tissue oxygenation at this time. Nevertheless, no patients have been withdrawn for safety concerns thus far, and compliance remains high.

TRIAL REGISTRATION

Clinicaltrials.gov NCT04020172; https://clinicaltrials.gov/study/NCT04020172.

Systemic Heparinization After Neuraxial Anesthesia in Vascular Surgery: A Retrospective Analysis

OBJECTIVES

The American Society of Regional Anesthesia and Pain Medicine's guidelines recommend a 1-hour interval after neuraxial anesthesia (NA) before systemic heparinization to mitigate the risk of spinal hematoma (SH). The study authors aimed to characterize the time interval between NA and systemic heparinization in vascular surgery patients (primary outcome). The secondary outcomes included the historic incidence of SH, and risk estimation of the SH formation based on available data. Heparin dose, length of surgery, difficulty and/or the number of NA attempts, and patient demographics were recorded.

DESIGN

A retrospective analysis between April 2012 and April 2022.

SETTING

A single (academic) center.

PARTICIPANTS

Vascular surgery patients.

INTERVENTIONS

Intravenous heparin administration.

MEASUREMENTS AND MAIN RESULTS

All (N = 311) vascular patients were reviewed, of whom 127 (5 femoral-femoral bypass, 67 femoral-popliteal bypass, and 55 endovascular aneurysm repairs [EVAR]) received NA and were included in the final analysis. Patients receiving general anesthesia alone (N = 184) were excluded. Neuraxial anesthesia included spinal (N = 119), epidural (N = 4), or combined spinal-epidural (N = 4) blocks. The average time between NA and heparin administration was 42.8 ± 22.1 minutes, with 83.7% of patients receiving heparin within 1 hour of NA. The time between NA and heparin administration was 40.4 ± 22.3, 50.1 ± 23.4, and 31.3 ± 12.5 minutes for femoral-femoral bypass, femoral-popliteal bypass, and EVAR, respectively. Heparin was administered after 1 hour of NA in 20% of femoral-femoral bypass, 27% of femoral-popliteal bypass, and 3.9% of EVAR patients. No SHs were reported during the study period.

CONCLUSIONS

The vast majority of vascular surgery patients at the authors' center received heparin within 1 hour of NA. Further studies are required to assess if their findings are consistent in other vascular surgery settings and/or centers.

Relationship between perioperative semaglutide use and residual gastric content: A retrospective analysis of patients undergoing elective upper endoscopy

STUDY OBJECTIVE

Semaglutide is a long-acting glucagon-like peptide-1 receptor agonist used for management of type 2 diabetes and/or obesity. To test the hypothesis that perioperative semaglutide use is associated with delayed gastric emptying and increased residual gastric content (RGC) despite adequate preoperative fasting, we compared the RGC of patients who had and had not taken semaglutide prior to elective esophagogastroduodenoscopy. The primary outcome was the presence of increased RGC.

DESIGN

Single-center retrospective electronic chart review.

SETTING

Tertiary hospital.

PATIENTS

Patients undergoing esophagogastroduodenoscopy under deep sedation/general anesthesia between July/2021-March/2022.

INTERVENTIONS

Patients were divided into two (SG = semaglutide, NSG = non-semaglutide) groups, according to whether they had received semaglutide within 30 days prior to the esophagogastroduodenoscopy.

MEASUREMENTS

Increased RGC was defined as any amount of solid content, or > 0.8 mL/Kg (measured from the aspiration/suction canister) of fluid content.

MAIN RESULTS

Of the 886 esophagogastroduodenoscopies performed, 404 (33 in the SG and 371 in the NSG) were included in the final analysis. Increased RGC was observed in 27 (6.7%) patients, being 8 (24.2%) in the SG and 19 (5.1%) in the NSG (p < 0.001). Semaglutide use [5.15 (95%CI 1.92-12.92)] and the presence of preoperative digestive symptoms (nausea/vomiting, dyspepsia, abdominal distension) [3.56 (95%CI 2.2-5.78)] were associated with increased RGC in the propensity weighted analysis. Conversely, a protective [0.25 (95%CI 0.16-0.39)] effect against increased RGC was observed in patients undergoing esophagogastroduodenoscopy combined with colonoscopy. In the SG, the mean time of preoperative semaglutide interruption in patients with and without increased RGC was 10.5 ± 5.5 and 10.2 ± 5.6 days, respectively (p = 0.54). There was no relationship between semaglutide use and the amount/volume of RGC found on esophagogastroduodenoscopy (p = 0.99). Only one case (in the SG) of pulmonary aspiration was reported.

CONCLUSIONS

Semaglutide was associated with increased RGC in patients undergoing elective esophagogastroduodenoscopy. Digestive symptoms prior to esophagogastroduodenoscopy were also predictive of increased RGC.

A simple technique to assess postoperative epidural functionality

To describe an alternative method of measuring the Epidural Waveform Analysis (EWA), a technique through which anesthesiologists can confirm the position of a needle and/or catheter tip in the epidural space. EWA consists of epidural catheter transduction with a pressure system typically used for invasive arterial blood pressure monitoring which generates a characteristic oscillatory waveform (provided the catheter tip is within the epidural space) in synchrony with the pulsatile epidural circulation. The technique requires a double-male connector, a 3-way stopcock and an arterial pressure extension tubing along with the patient's existing arterial line setup while ensuring a meticulously sterile technique to mitigate the risks of neuraxial infection. The technique described herein has been successfully and routinely applied within our institution to measure EWA with the advantage of being potentially less wasteful. EWA allows anesthesiologists to confirm the correct position of an epidural needle/catheter. We describe a method of successfully measuring EWA while reducing wastefulness.

Plasma bupivacaine levels (total and free/unbound) during epidural infusion in liver resection patients: a prospective, observational study

INTRODUCTION

Liver resection patients may be at an increased risk of local anesthetic (LA) toxicity because the liver is essential for metabolizing LA and producing proteins (mainly α1-acid glycoprotein (AAG)) that bind to it and reduce the free (and pharmacologically active/toxic) levels in circulation. The liver resection itself, manipulation during surgery, and pre-existing liver disease may all interfere with normal hepatic protein synthesis and result in an attenuation of the increased AAG (a positive acute-phase protein) that normally occurs postoperatively. The purpose of this study was to determine whether the AAG response is attenuated postoperatively following liver resection and whether patients approach toxicity thresholds with continuous postoperative epidural infusion of bupivacaine.

METHODS

Prospective, observational study with blood drawn preoperatively, in the postanesthetic care unit, on postoperative day (POD) 2, and prior to discontinuation of epidural analgesia on POD3/POD4. Plasma was analyzed for total and unbound bupivacaine via liquid chromatography-mass spectrometry and AAG via ELISA. Signs/symptoms of local anesthetic systemic toxicity (LAST), pain, and sedation scores were also recorded.

RESULTS

For the 19 patients completed, total plasma bupivacaine was correlated with total administered, but unbound levels were not associated with the total administered. Unlike non-hepatectomy surgery where unbound LA plasma levels remain stable (or decrease) with continuous postoperative epidural administration, we observed an overall increase. Several patients approached toxicity thresholds and 47% reported at least one symptom of LAST, but no epidurals were discontinued because of LAST. In contrast to the AAG response reported following major non-liver surgery where AAG levels increase twofold, we observed a reduction until POD2 and the magnitude was proportional to resection weight.

DISCUSSION

Our results are supported by the literature in suggesting that major liver resection patients may be at an increased vulnerability for LAST. Factors such as the extent of liver disease, resection and intraoperative blood loss should be considered when using continuous postoperative epidural infusion of bupivacaine and vigilance should be used in monitoring, for signs/symptoms of LAST, even for those subtle and non-specific. Future research will be required to verify these findings.

TRIAL REGISTRATION NUMBER

NCT03145805.

Caudal catheter placement for repeated epidural morphine doses after neonatal upper abdominal surgery

Effective pain control after major surgery in neonates presents many challenges. Parenteral opioids (and co-analgesics) are often used but inadequate analgesia and oversedation are not uncommon. Although continuous thoracic epidural analgesia is highly effective and opioid-sparing, its associated risks and the need for staff with specialised skills and/or neonatal intensive care unit staff buy-in may preclude this option even in many academic centres. We present the case of a six-day-old infant who underwent upper abdominal surgery and received intermittent morphine doses via a tunnelled caudal epidural catheter, which provided satisfactory analgesia and facilitated early extubation.

Retrospective review of time to uterotonic administration and maternal outcomes following post-partum hemorrhage

OBJECTIVE

Despite advances in health care and ample resources, post-partum hemorrhage (PPH) rates are increasing in high income countries. Although guidelines recommend therapeutic uterotonics, timing of administration is open to judgement and most often based on (inherently inaccurate) visual estimates of blood loss. With severe hemorrhage, every minute of delay can have significant consequences. Our objective was to examine the timing of uterotonic administration and its impact upon maternal outcomes. We hypothesized that increased time to uterotonic administration following the identification of PPH, would be associated with a greater decline in hemoglobin (Hb) and higher odds of hypotension and transfusion.

METHODS

We reviewed all cases of PPH that occurred at an academic centre between June 2015 and September 2017. All cases of primary PPH (i.e., those declared within 24 h of delivery with estimated blood loss [EBL] >500 mL for vaginal and >1000 mL for cesarean deliveries) were analyzed. Patient records were excluded if they were missing information regarding time of PPH declaration, uterotonic administration, and/or Hb measures, or if a pre-existing medical condition could have contributed to PPH.

RESULTS

Of 4397 births, there were 259 (5.9%) cases of primary PPH, of which 128 were included in this analysis. For these patients, each 5-minute delay in uterotonic treatment was associated with 26% higher odds of hypotension following delivery of any type. For vaginal deliveries (n = 86), each 5-minute delay was associated with 31% and 34% higher odds of hypotension and transfusion, respectively.

CONCLUSION

In this study, delay in administration of therapeutic uterotonics was associated with a higher incidence of hypotension and transfusion in primary PPH patients.

Comparison of strategies for adherence to venous thromboembolism prophylaxis in high-risk surgical patients: a before and after intervention study

BACKGROUND

Venous thromboembolism (VTE) is a major cause of perioperative morbimortality. Despite significant efforts to advance evidence-based practice, prevention rates remain inadequate in many centres.

OBJECTIVE

To evaluate the effectiveness of different strategies aimed at improving adherence to adequate VTE prophylaxis in surgical patients at high risk of VTE.

METHOD

Before and after intervention study conducted at a tertiary hospital. Adherence to adequate VTE prophylaxis was compared according to three strategies consecutively implemented from January 2019 to December 2020. A dedicated hospitalist physician alone (strategy A) or in conjunction with a nurse (strategy B) overlooked the postoperative period to ensure adherence and correct inadequacies. Finally, a multidisciplinary team approach (strategy C) focused on promoting adequate VTE prophylaxis across multiple stages of care-from the operating room (ie, preoperative team-based checklist) to collaboration with clinical pharmacists in the postoperative period-was implemented.

RESULTS

We analysed 2074 surgical patients: 783 from January to June 2019 (strategy A), 669 from July 2019 to May 2020 (strategy B), and 622 from June to December 2020 (strategy C). VTE prophylaxis adherence rates for strategies (A), (B) and (C) were (median (25th-75th percentile)) 43.29% (31.82-51.69), 50% (42.57-55.80) and 92.31% (91.38-93.51), respectively (p<0.001; C>A=B). There was a significant reduction in non-compliance on all analysed criteria (risk stratification (A (25.5%), B (22%), C (6%)), medical documentation (A (68%), B (55.2%) C (9%)) and medical prescription (A (51.85%), B (48%), C (6.10%)) after implementation of strategy C (p<0.05). Additionally, a significant increase in compliance with adequate dosage, dosing interval and scheduling of the prophylactic regimen was observed.

CONCLUSION

Perioperative VTE prophylaxis strategies that relied exclusively on physicians and/or nurses were associated with suboptimal execution and prevention. A multidisciplinary team-based approach that covers multiple stages of patient care significantly increased adherence to adequate VTE prophylaxis in surgical patients at high risk of developing perioperative VTE.

Adductor canal block with or without added magnesium sulfate following total knee arthroplasty: a multi-arm randomized controlled trial

PURPOSE

Postoperative analgesia following total knee arthroplasty (TKA) often includes intrathecal opioids, periarticular injection (PAI) of local anesthetic, systemic multimodal analgesia, and/or peripheral nerve blockade. The adductor canal block (ACB) provides analgesia without muscle weakness and magnesium sulphate (MgSO₄) may extend its duration. The purpose of this trial was to compare the duration and quality of early post-TKA analgesia in patients receiving postoperative ACB (± MgSO₄) in addition to standard care.

METHODS

Elective TKA patients were randomized to: 1) sham ACB, 2) ropivacaine ACB, or 3) ropivacaine ACB with added MgSO₄. All received spinal anesthesia with intrathecal morphine, intraoperative PAI, and multimodal systemic analgesia. Patients and assessors remained blinded to allocation. Anesthesiologists knew whether patients had received sham or ACB but were blinded to MgSO_4. The primary outcome was time to first analgesic (via patient-controlled analgesia [PCA] with iv morphine) following ACB. Secondary outcomes were morphine consumption, side effects, visual analogue scale pain scores, satisfaction until 24 hr postoperatively, and length of stay.

RESULTS

Of 130 patients, 121 were included. Nine were excluded post randomization: four were protocol violations, three did not meet inclusion criteria, and two had severe pain requiring open label blockade. There were no differences in the median [interquartile range] time to first PCA request: sham, 310 min [165-550]; ropivacaine ACB, 298 min [120-776]; and ropivacaine ACB with MgSO₄, 270 min [113-780] (P = 0.96). Similarly, we detected no differences in resting pain, opioid consumption, length of stay, or associated side effects until 24 hr postoperatively.

CONCLUSION

We found no analgesic benefit of a postoperative ACB, with or without added MgSO₄, in TKA patients undergoing spinal anesthesia and receiving intrathecal morphine, an intraoperative PAI, and multimodal systemic analgesia.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02581683); registered 21 October 2015.

Immune-Related Adverse Events Associated With Immune Checkpoint Inhibitor Therapy

As part of immune surveillance, killer T lymphocytes search for cancer cells and destroy them. Some cancer cells, however, develop escape mechanisms to evade detection and destruction. One of these mechanisms is the expression of cell surface proteins which allow the cancer cell to bind to proteins on T cells called checkpoints to switch off and effectively evade T-cell-mediated destruction. Immune checkpoint inhibitors (ICIs) are antibodies that block the binding of cancer cell proteins to T-cell checkpoints, preventing the T-cell response from being turned off by cancer cells and enabling killer T cells to attack. In other words, ICIs restore innate antitumor immunity, as opposed to traditional chemotherapies that directly kill cancer cells. Given their relatively excellent risk-benefit ratio when compared to other forms of cancer treatment modalities, ICIs are now becoming ubiquitous and have revolutionized the treatment of many types of cancer. Indeed, the prognosis of some patients is so much improved that the threshold for admission for intensive care should be adjusted accordingly. Nevertheless, by modulating immune checkpoint activity, ICIs can disrupt the intricate homeostasis between inhibition and stimulation of immune response, leading to decreased immune self-tolerance and, ultimately, autoimmune complications. These immune-related adverse events (IRAEs) may virtually affect all body systems. Multiple IRAEs are common and may range from mild to life-threatening. Management requires a multidisciplinary approach and consists mainly of immunosuppression, cessation or postponement of ICI treatment, and supportive therapy, which may require surgical intervention and/or intensive care. We herein review the current literature surrounding IRAEs of interest to anesthesiologists and intensivists. With proper care, fatality (0.3%-1.3%) is rare.

Erector Spinae Plane Block When Neuraxial Analgesia Is Contraindicated by Clotting Abnormalities

We describe 4 cases in which patients with coagulopathies, an absolute contraindication to epidural/paravertebral blocks, received an erector spinae plane block to manage severe thoracic pain with respiratory impairment. Intubation was avoided in 2 cases, and weaning from the ventilator was facilitated in 2 cases. Ultrasound-guided erector spinae plane block is simple to perform, has a low risk profile, and provides an excellent analgesic alternative.

Orotracheal intubation incorporating aerosol-mitigating strategies by anaesthesiologists, intensivists and emergency physicians: a simulation study

Background

Orotracheal intubation (OTI) can result in aerosolisation leading to an increased risk of infection for healthcare providers, a key concern during the COVID-19 pandemic.

Objective

This study aimed to evaluate the OTI time and success rate of two aerosol-mitigating strategies under direct laryngoscopy and videolaryngoscopy performed by anaesthesiologists, intensive care physicians and emergency physicians who were voluntarily recruited for OTI in an airway simulation model.

Methodology

The outcomes were successful OTI, degree of airway visualisation and time required for OTI. Not using a stylet during OTI reduced the success rate among non-anaesthesiologists and increased the time required for intubation, regardless of the laryngoscopy device used.

Results

Success rates were similar among physicians from different specialties during OTI using videolaryngoscopy with a stylet. The time required for successful OTI by intensive care and emergency physicians using videolaryngoscopy with a stylet was longer compared with anaesthesiologists using the same technique. Videolaryngoscopy increased the time required for OTI among intensive care physicians compared with direct laryngoscopy. The aerosol-mitigating strategy under direct laryngoscopy with stylet did not increase the time required for intubation, nor did it interfere with OTI success, regardless of the specialty of the performing physician.

Conclusions

The use of a stylet within the endotracheal tube, especially for non-anaesthesiologists, had an impact on OTI success rates and decreased procedural time.

Postpartum reverse-Takotsubo from pheochromocytoma diagnosed by bedside point-of-care ultrasound: A case report

Point-of-care ultrasound is invaluable in the setting of obstetric anesthesia, where the differential diagnosis for dyspnea, hypoxemia and/or hemodynamic abnormalities is broad. This report describes a previously apparently healthy parturient with an uncomplicated pregnancy at 35-weeks gestation who underwent an emergency cesarean section under general anesthesia due to severe acute abdominal pain and fetal bradycardia. Intraoperatively, she presented with severe hypertension and tachycardia that were difficult to control and associated with ischemic ECG changes. In the immediate postoperative period, she developed retrosternal tightness and dyspnea, and a bedside point-of-care ultrasound scan revealed a grossly dilated and hypokinetic left ventricle, as well as diffuse B-lines throughout all lung fields - consistent with cardiogenic pulmonary edema. She was admitted to the intensive care unit, where she recovered over several days. Pheochromocytoma was subsequently diagnosed, and she eventually underwent uneventful elective adrenalectomy after appropriate endocrine and hemodynamic optimization.

Efficacy and Safety of Magnesium for the Management of Chronic Pain in Adults: A Systematic Review

Chronic pain is a highly prevalent and complex health problem that is associated with a heavy symptom burden, substantial economic and social impact, and also, very few highly effective treatments. This review examines evidence for the efficacy and safety of magnesium in chronic pain. The previously published protocol for this review was registered in International Prospective Register of Systematic Reviews (PROSPERO), MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched until September 2018. We included randomized controlled trials (RCTs) comparing magnesium (at any dose, frequency, or route of administration) with placebo using participant-reported pain measures. A total of 9 RCTs containing 418 participants were included. Three studies examined neuropathic pain (62 participants), 3 examined migraines (190 participants), 2 examined complex regional pain syndrome (86 participants), and 1 examined low back pain with a neuropathic component (80 participants). Heterogeneity of included studies precluded any meta-analyses. No judgment could be made about safety because adverse events were inconsistently reported in the included studies. Evidence of analgesic efficacy from included studies was equivocal. However, reported efficacy signals in some of the included trials provide a rationale for more definitive studies. Future, larger-sized trials with good assay sensitivity and better safety assessment and reporting, as well as careful attention to formulations with optimal bioavailability, will serve to better define the role of magnesium in the management of chronic pain.

Interscalene Block in an Anesthetized Adult with Hypertrophic Obstructive Cardiomyopathy Undergoing Clavicle Fracture Reduction

Whether regional anesthesia procedures should be performed in heavily sedated/anesthetized adults remains controversial. One of the purported advantages of performing regional nerve blocks in conversant patients is early warning against major nerve injury and, arguably, early detection of local anesthetic systemic toxicity. A 60-year-old man with hypertrophic obstructive cardiomyopathy (HOCM) underwent a clavicle fracture repair under general anesthesia. Intraoperative transesophageal echocardiography revealed dynamic left ventricular outflow track obstruction and systolic anterior motion of the posterior mitral valve leaflet. In part based on such echo findings, he received an ultrasound-guided interscalene plus a superficial cervical plexus block for postoperative analgesia prior to emergence from general anesthesia. Given the lack of robust data on the safety of ultrasound-guided regional techniques in heavily sedated/anesthetized adults, we use the example of echographic evidence of significant HOCM to argue for a pragmatic and individualized approach when faced with unusual situations in which the pros of such an approach may outweigh the cons - in this case for performing an interscalene block on an anesthetized adult.

Co-induction with a vasopressor "chaser" to mitigate propofol-induced hypotension when intubating critically ill/frail patients-A questionable practice

Prophylactic administration of a vasopressor to mitigate the hypotensive effect of propofol (and/or other co-induction agents) during sedation/anesthesia immediately prior to tracheal intubation in frail patients in the intensive care unit and emergency and operating rooms appears to be not an uncommon practice. We submit that this practice is unnecessary and potentially harmful. Despite restoring the blood pressure, phenylephrine, for instance, may have an additive or synergistic effect with propofol in reducing the cardiac output and, ultimately, organ perfusion. Airway instrumentation often leads to sympathetic activation and hypertension (thereby increasing myocardial oxygen consumption) which may be exacerbated by an arbitrary prophylactic dose of phenylephrine. Finally, in spite of the well-recognized need to reduce dosages of propofol in frail patients, excessive doses are commonly given, leading to hypotension. We herein discuss each of these points and suggest alternative techniques to promote a stable induction in frail patients.

[Knowledge retention after focused cardiac ultrasound training: a prospective cohort pilot study]

BACKGROUND AND OBJECTIVES

Focused Cardiac Ultrasound (FoCUS) has proven instrumental in guiding anesthesiologists' clinical decision-making process. Training residents to perform and interpret FoCUS is both feasible and effective. However, the degree of knowledge retention after FoCUS training remains a subject of debate. We sought to provide a description of our 4-week FoCUS curriculum, and to assess the knowledge retention among anesthesia residents at 6 months after FoCUS rotation.

METHODS

A prospective analysis involving eleven senior anesthesia residents was carried out. At end of FoCUS Rotation (EOR) participants completed a questionnaire (evaluating the number of scans completed and residents' self-rated knowledge and comfort level with FoCUS), and a multiple-choice FoCUS exam comprised of written- and video-based questions. Six months later, participants completed a follow-up questionnaire and a similar exam. Self-rated knowledge and exam scores were compared at EOR and after 6 months. Spearman correlations were conducted to test the relationship between number of scans completed and exam scores, perceived knowledge and exam scores, and number of scans and perceived knowledge.

RESULTS

Mean exam scores (out of 50) were 44.1 at EOR and 43 at the 6-month follow-up. Residents had significantly higher perceived knowledge (out of 10) at EOR (8.0) than at the 6-month follow-up (5.5), p=0.003. At the EOR, all trainees felt comfortable using FoCUS, and at 6 months 10/11 still felt comfortable. All the trainees had used FoCUS in their clinical practice after EOR, and the most cited reason for not using FoCUS more frequently was the lack of perceived clinical need. A strong and statistically significant (rho=0.804, p=0.005) correlation between number of scans completed during the FoCUS rotation and 6-month follow-up perceived knowledge was observed.

CONCLUSION

Four weeks of intensive FoCUS training results in adequate knowledge acquisition and 6-month knowledge retention.

Use of Recombinant Activated Factor VII after Axillofemoral Bypass Grafting

Recombinant activated factor VII (rFVIIa) is a powerful prohaemostatic agent that theoretically predisposes to thrombosis after peripheral vascular surgery. We report the use of rFVIIa to reduce bleeding in a patient after axillofemoral bypass grafting for ruptured aorto-iliac pseudoaneurysm. Despite the increased risk of thrombosis, the patient made an uneventful recovery with preserved graft patency. The favourable result suggests that rFVIIa should be considered even in vascular surgical patients, if the risks of continued bleeding outweigh those of thrombosis. Better risk estimation is only possible if reports of rFVIIa use in vascular patients continue to appear and through controlled trials.

Right Upper Lobe Collapse Secondary to an Anomalous Bronchus after Endotracheal Intubation for Routine Surgery

Perioperative hypoxaemia is a common but serious problem with well recognised causes. However, an anomalous bronchus causing lobar collapse as a cause is seldom mentioned. A healthy young male patient was anaesthetised for a knee operation. He required reintubation immediately postoperatively for hypoxia. He was found to have right upper lobe collapse. Fibreoptic examination of the trachea demonstrated an anomalous bronchus as the cause. Intra-operatively, the endotracheal tube had been inserted too deeply and the bronchial orifice had been obstructed by the tip. It took several hours for the lung to re-expand. Greater awareness of this potential complication is needed.

Magnesium for the Management of Chronic Noncancer Pain in Adults: Protocol for a Systematic Review

Background

Chronic pain is a highly prevalent and complex health problem that is associated with a severe symptom burden, as well as substantial economic and social impact. Many patients with chronic pain still suffer from unrelieved or undertreated pain due to the incomplete efficacy and dose-limiting adverse effects of current therapies. Long-term and high-dose opioid use has considerably increased in the past 20 years despite limited evidence supporting its effectiveness in several chronic pain conditions, and serious concerns have emerged regarding adverse effects and potential misuse. Until recently, the steady increase in opioid prescribing rates has been associated with rising opioid-related mortality and other serious problems, emphasizing the need for better nonopioid therapies. Emerging evidence supports the safe use of magnesium in controlling chronic pain, but its overall efficacy and safety is still unclear.

Objective

This paper aims to assess the efficacy and safety of magnesium compared with a placebo for the treatment of chronic noncancer pain.

Methods

We will conduct a detailed search on Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE from their inception until the date the searches are run to identify relevant randomized controlled trials. The reference lists of retrieved studies as well as Web-based trial registries will also be searched. We will include randomized double-blind trials comparing magnesium (at any dose, frequency, or route of administration) with placebo using participant-reported pain assessment. Two reviewers will independently evaluate studies for eligibility, extract data, and assess trial quality and potential bias. Risk of bias will be assessed using criteria outlined in the Cochrane Handbook for Systematic Review of Interventions. Primary outcomes for this review will include any validated measure of pain intensity or pain relief. Dichotomous data will be used to calculate the risk ratio and number needed to treat or harm. The quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

Results

This protocol is grant-funded and has undergone a peer-review process through the Queen’s University Department of Anesthesiology and Perioperative Medicine Vandewater Endowed Studentship. This project is also supported, in part, by the Chronic Pain Network of the Canadian Institutes of Health Research Strategy for Patient-Oriented Research. The electronic database search strategies are currently being developed and modified. The entire review is expected to be completed by January 1, 2019.

Conclusions

The completion of this review is expected to identify available high-quality evidence describing the efficacy and safety of magnesium for the treatment of chronic noncancer pain.

International Registered Report Identifier (IRRID)

PRR1-10.2196/11654

Inattentional blindness in anesthesiology: A simulation study

STUDY OBJECTIVES

Inattentional blindness is the psychological phenomenon of inability to see the unexpected even if it is in plain view. We hypothesized that anesthesiologists may overlook unexpected intraoperative events whereas medical students, lacking in intraoperative monitoring experience and knowledge, may be more likely to notice such events.

DESIGN

A simulation study using a video of a simulated septic patient undergoing abdominal surgery.

SETTING

A large academic center.

PARTICIPANTS

31 certified anesthesiologists and 46 upper-year medical students.

INTERVENTIONS

None. Participants watched a video of a simulated surgery and scored the abnormalities they saw.

MEASUREMENTS

These abnormalities included abnormal physiologic parameters consistent with the condition of the simulated septic patient, and two unexpected but plausible events: head movement and a leaky central line catheter.

MAIN RESULTS

Students were significantly more likely than anesthesiologists to notice head movement (p<0.001).

Hemorrhagic shock after minor laparoscopic procedures

Severe bleeding from injury to abdominal wall blood vessels during minor laparoscopic procedures can occur. Two cases of shock presenting several hours after surgery are presented.