PReoperative very low-Energy diets for obese PAtients undergoing non-bariatric surgery Randomized Evaluation (PREPARE): a protocol for a pilot randomized controlled trial.

BACKGROUND: Patients with obesity presenting in need of surgical intervention are at 2-to-sixfold higher risk of prolonged hospitalization, infectious morbidity, venous thromboembolism, and more. To mitigate some of these concerns, prescribed preoperative weight loss via very low-energy diets (VLEDs) has become a standard of care for patients with obesity undergoing bariatric surgery. While VLEDs have become standard prior to bariatric surgery, their application in other surgical settings remains limited. A large, definitive trial is required to resolve the uncertainty surrounding their use in these patients. Prior to a definitive trial to compare the efficacy of VLEDs in patients with obesity undergoing major non-bariatric surgery, we require a pilot trial. We argue a pilot trial will provide the following critical feasibility insights: (1) assessment of recruitment ability, (2) evaluation of adherence to VLED regimens, and (3) assessment of our ability follow patients completely. METHODS: The proposed trial will be a multi-center, surgeon, outcome assessor, and data-analyst blinded, parallel pilot randomized controlled trial (RCT). Patients older than 18 years of age with a body mass index (BMI) of greater than 30 kg/m2 undergoing major elective non-bariatric surgery will be eligible for inclusion. Consecutive patients will be allocated 1:1 according to a computer-generated randomization schedule. Randomization will be stratified by center and will employ randomly permutated blocks. All patients in the intervention group will receive standard patient counseling on weight loss and an active VLED protocol. The preoperative VLED protocol will utilize commercially available weight loss products for three weeks preoperatively. The primary outcomes (randomization percentage, recruitment rate, intervention adherence, follow-up completion, network development) will assess feasibility. Descriptive statistics will be used to characterize the study sample. DISCUSSION: The PREPARE pilot RCT will aim to provide feasibility and safety data that will allow for the successful completion of the definitive PREPARE trial that has the potential to provide practice changing data pertaining to the regular use of VLEDs as a means of pre-habilitation for patients with obesity undergoing major non-bariatric surgery. TRIAL REGISTRATION: This study was registered on ClinicalTrials.gov (reference #NCT05918471) on June 23, 2023.

Conversion between B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide in perioperative risk assessment: protocol for a prospective cohort study.

INTRODUCTION: Both B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-pro-BNP) are used to identify patients at risk of perioperative vascular events, but prognostic thresholds have been established in a large prospective cohort for NT-pro-BNP only. We designed this study to inform perioperative risk interpretation of BNP values. Our primary objective is to validate a formula to convert BNP to NT-pro-BNP concentrations before non-cardiac surgery. The secondary objective is to determine the association between BNP categories (established based on conversion from NT-pro-BNP categories) and a composite outcome of myocardial injury after non-cardiac surgery (MINS) and vascular death. METHODS AND ANALYSIS: This is a single-centre, prospective cohort study in patients undergoing non-cardiac surgery who are >65 years old, Revised Cardiac Risk Index ≥1 or >45 years old with significant cardiovascular disease. BNP and NT-pro-BNP will be measured preoperatively, and troponin measurements will be analysed on postoperative days 1, 2 and 3. MINS and vascular death will be ascertained up to 30 days after surgery. The primary analyses will compare measured NT-pro-BNP values to those predicted by an existing formula (from a non-surgical population) based on BNP concentrations and patient characteristics, and recalibrate and update the formula with additional variables. Secondary analyses will estimate the relationship between categories of measured BNP (corresponding to established NT-pro-BNP thresholds) and the composite of MINS and vascular death. The target sample size of 431 patients is based on our primary analysis (assessing the conversion formula). ETHICS AND DISSEMINATION: Ethics approval has been obtained by the Queen's University Health Sciences Research Ethics Board, and all participants will provide informed consent for participation in the study. The results will be submitted for publication in conferences and in a peer-reviewed journal, and will inform perioperative vascular risk interpretation of preoperative BNP. TRIAL REGISTRATION NUMBER: NCT05352698.

Magnesium-Based Trigger Point Infiltrations Versus Local Anaesthetic Infiltrations in Chronic Pelvic Myofascial Pain: A Randomized, Double-Blind, Controlled Study.

OBJECTIVE: To determine if a novel, magnesium-based trigger point infiltration formulation is more effective in treating chronic myofascial pelvic pain than lidocaine-only infiltration. METHODS: This was a single-centre, double-blind, randomized controlled trial of women diagnosed with chronic pelvic myofascial pain associated with trigger points. We compared a novel magnesium-based infiltration formulation with lidocaine infiltration of trigger points and with a control group of participants who were waitlisted for a chronic pain clinic. Treatment groups completed a 12-week program that included 8 trigger point injection treatments and 9 visits during which pain scores were recorded and questionnaires administered. The primary outcome measure was change in mean pain score between baseline and the final visit. Secondary outcomes included pain with function scores, scores on the World Health Organization Quality of Life questionnaire, procedural pain, concomitant medication use, and complications. RESULTS: We assigned 44 women diagnosed with chronic myofascial pelvic pain associated with trigger points to either the magnesium-based infiltrate (n = 15), lidocaine infiltrate (n = 17), or waitlist (n = 12) group. In the intent-to-treat analysis, a clinically relevant decrease in mean pain score out of 10 was observed in the magnesium-based (-2.6 ± 3.2) and lidocaine (-2.9 ± 3.1) infiltration groups, but not in the waitlist group (-0.5 ± 2.3). The per protocol analysis post-hoc tests, adjusted for multiple comparisons, found a significant difference in the average change in pain score between the magnesium-based infiltrate and the waitlist groups (P = 0.045), while differences between the lidocaine infiltrate and waitlist groups approached statistical significance (P = 0.052). Both treatment groups saw improvements in pain with function and quality of life scores. CONCLUSION: While this study is underpowered, it does not support the use of a magnesium-based trigger point infiltrate in the treatment of chronic myofascial pelvic pain over lidocaine-only infiltration. Nonetheless, these results are consistent with current management recommendations and suggest improvements in pain, pain with function, and quality of life scores with either magnesium-based or lidocaine-only infiltration. We outline an approach to assessment and treatment that can be adopted by general gynaecologists.

Association between postsurgical pain and heart rate variability: protocol for a scoping review.

INTRODUCTION: Surgical interventions can elicit neuroendocrine responses and sympathovagal imbalance, ultimately affecting cardiac autonomic function. Cardiac complications account for 30% of postoperative complications and are the leading cause of morbidity and mortality following non-cardiac surgery. One cardiovascular parameter, heart rate variability (HRV), has been found to be predictive of postoperative morbidity and mortality. HRV is defined as variation in time intervals between heartbeats and is affected by cardiac autonomic balance. Furthermore, altered HRV has been shown to predict cardiovascular events in non-surgical settings. In multiple studies, experimentally induced pain in healthy humans leads to reduced HRV suggesting a causal relationship. In a different studies, chronic pain has been associated with altered HRV, however, in the setting of clinical pain conditions, it remains unclear how much HRV impairment is due to pain itself versus autonomic changes related to analgesia. We aim to review the available evidence describing the association between postsurgical pain and HRV alterations in the early postoperative period. METHODS AND ANALYSIS: We will conduct a scoping review of relevant studies using detailed searches of MEDLINE and EMBASE, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Included studies will involve participants undergoing non-cardiac surgery and investigate outcomes of (1) measures of pain intensity; (2) measures of HRV and (3) statistical assessment of association between #1 and #2. As secondary review outcomes included studies will also be examined for other cardiovascular events and for their attempts to control for analgesic treatment and presurgical HRV differences among treatment groups in the analysis. This work aims to synthesise available evidence to inform future research questions related to postsurgical pain and cardiac complications. ETHICS AND DISSEMINATION: Ethics review and approval is not required for this review. The results will be submitted for publication in peer-reviewed journals.

Scoping review of the association between postsurgical pain and heart rate variability parameters.

Surgical interventions can elicit neuroendocrine and sympathovagal responses, leading to cardiac autonomic imbalance. Cardiac complications account for approximately 30% of postoperative complications. Altered heart rate variability (HRV) was initially described in the 1970s as a predictor of acute coronary syndromes and has more recently been shown to be an independent predictor of postoperative morbidity and mortality after noncardiac surgery. In general, HRV reflects autonomic balance, and altered HRV measures have been associated with anesthetic use, chronic pain conditions, and experimental pain. Despite the well-documented relationship between altered HRV and postsurgical outcomes and various pain conditions, there has not been a review of available evidence describing the association between postsurgical pain and HRV. We examined the relationship between postsurgical pain and HRV. MEDLINE and EMBASE databases were searched until December 2020 and included all studies with primary data. Two reviewers independently assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Review of Interventions. A total of 8 studies and 1002 participants were included. Studies examined the association of postsurgical pain and HRV or analgesia nociception index derived from HRV. There was a statistically significant association between HRV measures and postsurgical pain in 6 of 8 studies. Heterogeneity of studies precluded meta-analyses. No studies reported cardiovascular outcomes. There is a potential association between postsurgical pain and HRV or analgesia nociception index, although results are likely impacted by confounding variables. Future studies are required to better delineate the relationship between postsurgical pain and HRV and impacts on cardiovascular outcomes.

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.

Humanization of critical care-psychological effects on healthcare professionals and relatives: a systematic review.

PURPOSE: To systematically review and evaluate the effects of humanized care of the critically ill on empathy among healthcare professionals, anxiety among relatives, and burnout and compassion fatigue in both groups. SOURCE: MEDLINE, PsycINFO, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL), and ProQuest Dissertations were searched from inception to 29 June 2017 for studies that investigated the effects of interventions with potential to humanize care of the critically ill on the following outcomes: empathy among critical care professionals, anxiety among relatives, and burnout and compassion fatigue in either group. We defined a humanizing intervention as one with substantial potential to increase physical or emotional proximity to the patient. Two reviewers independently selected studies, extracted data, and assessed risk of bias and data quality. PRINCIPAL FINDINGS: Twelve studies addressing four discrete interventions (liberal visitation, diaries, family participation in basic care, and witnessed resuscitation) and one mixed intervention were included. Ten studies measured anxiety among 1,055 relatives. Two studies measured burnout in 288 critical care professionals. None addressed empathy or compassion fatigue. Eleven of the included studies had an overall high risk of bias. No pooled estimates of effect were calculated as a priori criteria for data synthesis were not met. CONCLUSIONS: We found insufficient evidence to make any quantitative assessment of the effect of humanizing interventions on any of these psychologic outcomes. We observed a trend towards reduced anxiety among family members who participated in basic patient care, liberal visitation, and diary keeping. We found conflicting effects of liberal visitation on burnout among healthcare professionals.

Perioperative Management for Abdominal Surgery in Bilateral Diaphragmatic Paralysis: A Case Report and Literature Review.

The optimal approach to postoperative analgesia in patients with bilateral diaphragmatic paralysis undergoing abdominal surgery remains unclear. We report a 69-year-old woman with bilateral diaphragmatic paralysis who underwent a laparoscopic hernia repair and an open laparotomy for reversal of a Hartmann procedure under general anesthesia. Postoperative analgesia was provided by intravenous opioid and epidural local anesthetic and opioid, respectively. The patient's trachea was successfully extubated at the end of both surgical procedures. Epidural analgesia was associated with better pain control and shorter intensive care unit stay.

Managing the perioperative patient on direct oral anticoagulants.

PURPOSE: Patients are increasingly treated with direct oral anticoagulants (DOACs) for the prevention of stroke due to non-valvular atrial fibrillation and for the treatment of venous thromboembolism. When these patients present for urgent or emergent surgical procedures, they present a challenge to the anesthesiologist who must manage perioperative risk due to anticoagulation. The purpose of this module is to review the literature surrounding the perioperative management of DOACs. Timing, laboratory monitoring, and availability of reversal agents are important considerations to optimize patients being treated with DOACs who require emergent surgery. PRINCIPAL FINDINGS: Laboratory tests are not recommended for routine monitoring of DOACs since they do not correlate well with anticoagulant activity. Most widely available laboratory tests lack the sensitivity to detect anticoagulant effects at low plasma concentrations. However, a normal thrombin time for dabigatran excludes clinically significant drug levels. If the risk of bleeding is judged to be high because of a recent dose of DOAC, various options are available to mitigate bleeding. When possible, surgery should be delayed for at least 12 hr after the last dose of DOAC. Activated charcoal may mitigate the anticoagulant effect caused by DOACs if administered less than two hours after the drug was ingested. Four-factor prothrombin complex concentrates (PCCs) may be useful to reduce life-threatening bleeding associated with factor Xa inhibitors. Activated PCCs have been shown to reverse abnormal coagulation tests associated with all DOACs, but there is a lack of reported evidence of clinical benefit. Idarucizumab is a specific antidote that is effective for reversal of anticoagulation due to dabigatran. An antidote for rivaroxaban and apixaban (andexanet alfa) as well as a universal antidote for all DOACs and heparin (PER977) are in clinical development. CONCLUSION: Perioperative management of anticoagulation due to DOACs is a growing concern as the number of patients prescribed these medications increases each year. These patients can be safely optimized for urgent or emergent surgery by giving appropriate consideration to timing, monitoring, and reversal agents.

Applying functional MRI to the spinal cord and brainstem.

Functional magnetic resonance imaging of the spinal cord (spinal fMRI) has facilitated the noninvasive visualization of neural activity in the spinal cord (SC) and brainstem of both animals and humans. This technique has yet to gain the widespread usage of brain fMRI, due in part to the intrinsic technical challenges spinal fMRI presents and to the narrower scope of applications it fulfills. Nonetheless, methodological progress has been considerable and rapid. To date, spinal fMRI studies have investigated SC function during sensory or motor task paradigms in spinal cord injury (SCI), multiple sclerosis (MS) and neuropathic pain (NP) patient populations, all of which have yielded consistent and sensitive results. The most recent study in our laboratory has successfully used spinal fMRI to examine cervical SC activity in a SCI patient with a metallic fixation device spanning the C(4) to C(6) vertebrae, a critical step in realizing the clinical utility of the technique. The literature reviewed in this article suggests that spinal fMRI is poised for usage in a wide range of patient populations, as multiple groups have observed intriguing, yet consistent, results using standard, readily available MR systems and hardware. The next step is the implementation of this technique in the clinic to supplement standard qualitative behavioral assessments of SCI. Spinal fMRI may offer insight into the subtleties of function in the injured and diseased SC, and support the development of new methods for treatment and monitoring.

In contrast to BOLD: signal enhancement by extravascular water protons as an alternative mechanism of endogenous fMRI signal change.

Despite the popularity and widespread application of functional magnetic resonance imaging (fMRI) in recent years, the physiological bases of signal change are not yet fully understood. Blood oxygen level-dependant (BOLD) contrast - attributed to local changes in blood flow and oxygenation, and therefore magnetic susceptibility - has become the most prevalent means of functional neuroimaging. However, at short echo times, spin-echo sequences show considerable deviations from the BOLD model, implying a second, non-BOLD component of signal change. This has been dubbed "signal enhancement by extravascular water protons" (SEEP) and is proposed to result from proton-density changes associated with cellular swelling. Given that such changes are independent of magnetic susceptibility, SEEP may offer new and improved opportunities for carrying out fMRI in regions with close proximity to air-tissue and/or bone-tissue interfaces (e.g., the prefrontal cortex and spinal cord), as well as regions close to large blood vessels, which may not be ideally suited for BOLD imaging. However, because of the interdisciplinary nature of the literature, there has yet to be a thorough synthesis, tying together the various and sometimes disparate aspects of SEEP theory. As such, we aim to provide a concise yet comprehensive overview of SEEP, including recent and compelling evidence for its validity, its current applications and its future relevance to the rapidly expanding field of functional neuroimaging. Before presenting the evidence for a non-BOLD component of endogenous functional contrast, and to enable a more critical review for the nonexpert reader, we begin by reviewing the fundamental principles underlying BOLD theory.