Pulmonary Vasodilator Response of Combined Inhaled Epoprostenol and Inhaled Milrinone in Cardiac Surgical Patients.

BACKGROUND: Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are major complications in cardiac surgery. Intraoperative management of patients at high risk of RV failure should aim to reduce RV afterload and optimize RV filling pressures, while avoiding systemic hypotension, to facilitate weaning from cardiopulmonary bypass (CPB). Inhaled epoprostenol and inhaled milrinone (iE&iM) administered in combination before CPB may represent an effective strategy to facilitate separation from CPB and reduce requirements for intravenous inotropes during cardiac surgery. Our primary objective was to report the rate of positive pulmonary vasodilator response to iE&iM and, second, how it relates to perioperative outcomes in cardiac surgery. METHODS: This is a retrospective cohort study of consecutive patients with PH or RV dysfunction undergoing on-pump cardiac surgery at the Montreal Heart Institute from July 2013 to December 2018 (n = 128). iE&iM treatment was administered using an ultrasonic mesh nebulizer before the initiation of CPB. Demographic and baseline clinical data, as well as hemodynamic, intraoperative, and echocardiographic data, were collected using electronic records. An increase of 20% in the mean arterial pressure (MAP) to mean pulmonary artery pressure (MPAP) ratio was used to indicate a positive response to iE&iM. RESULTS: In this cohort, 77.3% of patients were responders to iE&iM treatment. Baseline systolic pulmonary artery pressure (SPAP) (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.24-2.16 per 5 mm Hg; P = .0006) was found to be a predictor of pulmonary vasodilator response, while a European System for Cardiac Operative Risk Evaluation (EuroSCORE II) score >6.5% was a predictor of nonresponse to treatment (≤6.5% vs >6.5% [reference]: OR, 5.19; 95% CI, 1.84-14.66; P = .002). Severity of PH was associated with a positive response to treatment, where a higher proportion of responders had MPAP values >30 mm Hg (42.4% responders vs 24.1% nonresponders; P = .0237) and SPAP values >55 mm Hg (17.2% vs 3.4%; P = .0037). Easier separation from CPB was also associated with response to iE&iM treatment (69.7% vs 58.6%; P = .0181). A higher proportion of nonresponders had a very difficult separation from CPB and required intravenous inotropic drug support compared to responders, for whom easy separation from CPB was more frequent. Use of intravenous inotropes after CPB was lower in responders to treatment (8.1% vs 27.6%; P = .0052). CONCLUSIONS: A positive pulmonary vasodilator response to treatment with a combination of iE&iM before initiation of CPB was observed in 77% of patients. Higher baseline SPAP was an independent predictor of pulmonary vasodilator response, while EuroSCORE II >6.5% was a predictor of nonresponse to treatment.

Intra-abdominal pressure during and after cardiac surgery: a single-centre prospective cohort study.

PURPOSE: While intra-abdominal hypertension (IAH) has been associated with adverse outcomes in multiple settings, the epidemiology and clinical implications of IAH in the context of cardiac surgery are less known. In this study, we aimed to describe the prevalence of IAH in patients undergoing cardiac surgery and determine its association with patient characteristics and postoperative outcomes. METHODS: We conducted a single-centre prospective cohort study in which intra-abdominal pressure was measured in the operating room after general anesthesia (T1), after the surgical procedure (T2), and two hours after intensive care unit (ICU) admission (T3) in a subset of patients. Intra-abdominal hypertension was defined as intra-abdominal pressure (IAP) ≥ 12 mm Hg. Postoperative outcomes included death, acute kidney injury (AKI), and length of stay in the ICU and hospital. RESULTS: A total of 513 IAP measurements were obtained from 191 participants in the operating room and 131 participants in the ICU. Intra-abdominal hypertension was present in 105/191 (55%) at T1, 115/191 (60%) at T2, and 31/131 (24%) at T3. Intra-abdominal pressure was independently associated with body mass index, central venous pressure, and mean pulmonary artery pressure but was not associated with cumulative fluid balance. Intraoperative IAH was not associated with adverse outcomes including AKI. CONCLUSIONS: Intra-abdominal hypertension is very common during cardiac surgery but its clinical implications are uncertain.

RéSUMé: OBJECTIF: Bien que l'hypertension intra-abdominale (HIA) ait été associée à des issues indésirables dans de multiples contextes, l'épidémiologie et les implications cliniques de l'HIA dans le contexte de la chirurgie cardiaque sont moins connues. Dans cette étude, nous avons cherché à décrire la prévalence de l'HIA chez les patients bénéficiant d'une chirurgie cardiaque et à déterminer son association avec les caractéristiques des patients et les issues postopératoires. MéTHODE: Nous avons mené une étude de cohorte prospective monocentrique dans laquelle la pression intra-abdominale a été mesurée en salle d'opération après une anesthésie générale (T1), après l'intervention chirurgicale (T2) et deux heures après l'admission à l'unité de soins intensifs (USI) (T3) dans un sous-ensemble de patients. L'hypertension intra-abdominale a été définie comme une pression intra-abdominale (PIA) ≥ 12 mmHg. Les issues postopératoires comprenaient le décès, l'insuffisance rénale aiguë (IRA), et la durée du séjour à l'USI et à l'hôpital. RéSULTATS: Au total, 513 mesures de la PIA ont été obtenues auprès de 191 participants en salle d'opération et de 131 participants à l'USI. L'hypertension intra-abdominale était présente chez 105/191 patients (55 %) à T1, 115/191 (60 %) à T2 et 31/131 (24 %) à T3. La pression intra-abdominale était indépendamment associée à l'indice de masse corporelle, à la pression veineuse centrale et à la pression artérielle pulmonaire moyenne, mais n'était pas associée à un bilan hydrique cumulatif. L'HIA peropératoire n'était pas associée à des issues indésirables, y compris à l'IRA. CONCLUSION: L'hypertension intra-abdominale est très fréquente lors d'une chirurgie cardiaque, mais ses implications cliniques sont incertaines.

Perioperative Right Ventricular Pressure Monitoring in Cardiac Surgery.

Right ventricular (RV) dysfunction is a cause of increased morbidity and mortality in both cardiac surgery and noncardiac surgery and in the intensive care unit. Early diagnosis of this condition still poses a challenge. The diagnosis of RV dysfunction traditionally is based on a combination of echocardiography, hemodynamic measurements, and clinical symptoms. This review describes the method of using RV pressure waveform analysis to diagnose and grade the severity of RV dysfunction. The authors describe the technique, optimal use, and pitfalls of this method, which has been used at the Montreal Heart Institute since 2002, and review the current literature on this method. The RV pressure waveform is obtained using a pulmonary artery catheter with the capability of measuring RV pressure by connecting a pressure transducer to the pacemaker port. The authors describe how RV pressure waveform analysis can facilitate the diagnosis of systolic and diastolic RV dysfunction, the evaluation of RV-arterial coupling, and help diagnose RV outflow tract obstruction. RV pressure waveform analysis also can be used to guide pharmacologic treatment and fluid resuscitation strategies for RV dysfunction.

Acute Right Ventricular Failure in Cardiac Surgery During Cardiopulmonary Bypass Separation: A Retrospective Case Series of 12 Years' Experience With Intratracheal Milrinone Administration.

OBJECTIVE: To report the authors' 12 years of experience with intratracheal milrinone administration and to assess the efficacy and limitations of intratracheal milrinone bolus administration for the treatment of unexpected acute right ventricular (RV) failure in patients undergoing cardiac surgery. DESIGN: Retrospective analysis. SETTING: Single-center university hospital. PARTICIPANTS: One hundred seventy-six patients (4.6%) undergoing on-pump cardiac surgery. INTERVENTIONS: Endotracheal tube administration of milrinone (5-mg bolus) after unexpected acute RV failure during separation from cardiopulmonary bypass (CPB) weaning. RV failure was defined as the simultaneous presence of all of the following criteria: (1) hemodynamic instability or difficult separation from CPB with associated elevated central venous pressure or abnormal RV pressure waveform, (2) >20% reduction of RV fractional area change from baseline evaluated by transesophageal echocardiography, and (3) anatomical visualization of impaired or absent RV wall motion by direct intraoperative visual inspection. MEASUREMENTS AND MAIN RESULTS: Intratracheal milrinone administration was found to improve RV failure in 109 patients (61.9%) whereas RV failure persisted in 67 patients (38.1%). Using a multiple logistic regression model, severely decreased left ventricular ejection fraction (<35% v >50%) (adjusted odds ratio [OR] 3.72; 95% confidence interval [CI] 1.2-11.3; p = 0.012), longer CPB time (adjusted OR 1.014; CI 1.01-1.02; p = 0.001) and elevated postoperative fluid balance (adjusted OR 1.39; CI 1.1-1.8; p = 0.02) were found to be significant predictors of persistent RV failure. CONCLUSION: Intratracheal instillation of milrinone was associated with clinical improvement of RV failure occurring during separation from CPB in almost two-thirds of patients. Factors limiting its therapeutic efficacy include severe left ventricular dysfunction, increased fluid balance, and long CPB time.

Attitudes Toward Opioids and Risk of Misuse/Abuse in Patients with Chronic Noncancer Pain Receiving Long-term Opioid Therapy.

Objectives: To determine the attitudes of patients toward long-term opioid therapy (LtOT) and the potential risk of misuse/abuse in patients with chronic noncancer pain (CNCP). Design: Prospective, descriptive epidemiological study. Setting: Multidisciplinary tertiary care pain center within the Montreal University Health Center. Subjects: Patients who had had at least one visit at least one year prior to the invitation. Methods: We used four questionnaires: demographic questionnaire, the Drug Attitude Inventory Modified (DAI-M), the Opioid Risk Tool (ORT), and the Screening Tool for Addiction Risk (STAR). All questionnaires were administered in their validated French version. Results: Three hundred seventy patients completed questionnaires. The response rate was 79.26%. Of those who responded, 61.62% women and 38.38% men, the mean age was 57 years. The patients had been treated with LtOT for an average of 6.31 years, and the median dose per day in morphine equivalents was 48.21 mg. The DAI-M showed that 32.16% had a positive attitude toward opioids, 39.73% had a negative attitude, and 22.16% had a neutral attitude. The ORT questionnaire demonstrated that 86.2% of the patients were at low risk of abuse/misuse, 13.2% were at moderate risk, and only 0.54% were at high risk. The STAR questionnaire showed that 4.2% had a low risk of abuse/misuse. Conclusions: Despite public opinion, patients treated with LtOT for CNCP and followed in a tertiary care pain center are at low risk for opioid misuse/abuse. We need to refine the way of prescribing opioids, should be selective with our patients, and should relive their pain adequately.

"CAPS" Cardiac Acute Pain Services-A Nationwide Survey From Canada.

OBJECTIVES: Acute Pain Services (APS) are well-established worldwide; however, their availability and use in cardiac surgery units are less widespread and, even where present, may be provided less consistently. The authors undertook this survey to assess the current organization of Cardiac Acute Pain Services (CAPS) in Canada. DESIGN: This was a prospectively administered survey. SETTING: This study included all centers in Canada that conducted adult cardiac surgery. PARTICIPANTS: The participants were anesthesiologists. INTERVENTION: A 20-item questionnaire covered the demographics, functioning and APS structure. RESULTS: The authors achieved a response rate of 100% with completed questionnaires from all 31 centers. Ten centers (32.3%) stated that they had a dedicated CAPS, 9 centers (29%) stated that they did not have an APS, and 12 centers (38.7%) had APS but no CAPS. At the time of the survey for the 10 centers with CAPS, 3 of the CAPS had a physician-run model, 4 had a combined physician and nurse service, and 1 used a combination of protocols, intensivists, and nurse practitioners. Nine centers had an anesthesiologist assigned to daily acute pain rounds. Only in 2 of 10 centers with CAPS were more than 50% of their cardiac surgery patients receiving care. In general, postoperative pain management was a protocol-driven activity. CONCLUSIONS: CAPS are varied in both structure and functioning. Further work is required both at the institutional and the national levels to improve the postoperative care and the pain-related outcomes of patients undergoing cardiac surgery.

Low-Dose Versus High-Dose Tranexamic Acid Reduces the Risk of Nonischemic Seizures After Cardiac Surgery With Cardiopulmonary Bypass.

OBJECTIVE: The incidence of postoperative nonischemic seizures associated with the use of tranexamic acid (TXA) and the possibility of prevention with a low-dose regimen of TXA were evaluated. DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PARTICIPANTS: A total of 12,195 patients who underwent cardiac surgical procedures under cardiopulmonary bypass (CPB) were evaluated. INTERVENTIONS: The files of every clinical seizure case diagnosed in the surgical intensive care unit between April 2006 and April 2014 were reviewed. Patients who experienced a postoperative seizure underwent a cerebral computed tomography scan to exclude an ischemic lesion. Dosage and type of antifibrinolytic used and surgery characteristics were retrieved from perfusion files. Low-dose TXA was defined as 1,000-mg bolus, 400-mg/h infusion, and 500 mg in CPB priming. High-dose TXA was defined as 30-mg/kg bolus, 15 mg/kg/h, and 2 mg/kg in CPB priming. RESULTS: No seizure was observed in the 886 patients who did not receive antifibrinolytics. A total of 98 clinical seizures (0.8%) were recorded in the intensive care unit, and ischemic cause was excluded in the majority of them after computed tomography scan results were reviewed (91 patients [93%]). Low-dose TXA was associated with fewer seizures than was high-dose TXA (46 of 7,452 cases [0.70%] v 34 of 2,190 cases [1.55%], respectively; p < 0.0001). Open-chamber cardiac surgery also was linked to a higher incidence of seizures compared with revascularization (80 of 6,662 [1.20%] and 11 of 5,533 [0.20%], respectively; p < 0.0001). CONCLUSIONS: Lower doses of TXA were associated with a lower incidence of nonischemic seizures compared with higher doses of the drug.

Prevalence of and risk factors for persistent postoperative nonanginal pain after cardiac surgery: a 2-year prospective multicentre study.

BACKGROUND: Persistent postoperative pain continues to be an underrecognized complication. We examined the prevalence of and risk factors for this type of pain after cardiac surgery. METHODS: We enrolled patients scheduled for coronary artery bypass grafting or valve replacement, or both, from Feb. 8, 2005, to Sept. 1, 2009. Validated measures were used to assess (a) preoperative anxiety and depression, tendency to catastrophize in the face of pain, health-related quality of life and presence of persistent pain; (b) pain intensity and interference in the first postoperative week; and (c) presence and intensity of persistent postoperative pain at 3, 6, 12 and 24 months after surgery. The primary outcome was the presence of persistent postoperative pain during 24 months of follow-up. RESULTS: A total of 1247 patients completed the preoperative assessment. Follow-up retention rates at 3 and 24 months were 84% and 78%, respectively. The prevalence of persistent postoperative pain decreased significantly over time, from 40.1% at 3 months to 22.1% at 6 months, 16.5% at 12 months and 9.5% at 24 months; the pain was rated as moderate to severe in 3.6% at 24 months. Acute postoperative pain predicted both the presence and severity of persistent postoperative pain. The more intense the pain during the first week after surgery and the more it interfered with functioning, the more likely the patients were to report persistent postoperative pain. Pre-existing persistent pain and increased preoperative anxiety also predicted the presence of persistent postoperative pain. INTERPRETATION: Persistent postoperative pain of nonanginal origin after cardiac surgery affected a substantial proportion of the study population. Future research is needed to determine whether interventions to modify certain risk factors, such as preoperative anxiety and the severity of pain before and immediately after surgery, may help to minimize or prevent persistent postoperative pain.

Patient attitudes and beliefs regarding pain medication after cardiac surgery: barriers to adequate pain management.

Several studies have outlined the impact of patient's beliefs on their level of pain relief after surgery and have underlined that misconceptions are barriers to effective pain relief. The aim of this survey was to evaluate the beliefs of the patients to help create a specifically adapted pain education program. After ethics approval, all patients scheduled to undergo cardiac surgery of any kind were approached and asked to complete a voluntary, non-nominative questionnaire that included the Barriers Questionnaire and the Screening Tool for Addiction Risk (STAR) Questionnaire. All completed questionnaires were collected from the charts every evening or the morning before surgery. Of 564 patients scheduled for surgery, 379 patients (67.5%) returned questionnaires. The average age was 60.3 years, and 66.0% were male. Results of the Barriers Questionnaire showed that 31% of patients were in strong agreement that "it is easy to become addicted to pain medication," 20% agreed that "good patients do not speak of their pain," and 36% believe that "pain medication should be saved in case pain worsens." Little or no gains have been made in decreasing misconceptions related to the treatment of pain. This study underlines the considerable need for and absolute necessity to provide pain education to patients undergoing cardiac surgery.

Evaluation of autonomic reserves in cardiac surgery patients.

OBJECTIVE: Autonomic nervous system dysfunction is a well-recognized but rarely evaluated risk factor for patients undergoing cardiac surgery. By measuring autonomic reserves in patients scheduled for cardiac surgery, the authors aimed to identify those with autonomic dysfunction and to evaluate their risk of perioperative complications. DESIGN: This was a prospective, observational study. SETTING: The study was conducted in a single academic center. PARTICIPANTS: Sixty-seven patients completed the study. INTERVENTIONS: Autonomic reserves were evaluated using analysis of heart rate variability (HRV) and blood pressure variability (BPV) after a Valsalva maneuver. MEASUREMENTS AND MAIN RESULTS: The patients were divided into 2 groups depending on their response to the autonomic challenge, a group with autonomic reserves (AR, n = 38) and a group with negligible autonomic reserves (NAR, n = 29). The groups were compared for baseline psychologic distress, demographic and medical profiles, autonomic response to morphine premedication and the induction of anesthesia, hemodynamic instability, the occurrence of decreases in cerebral oxygen saturation, and postoperative complications. Patients in the NAR group had significantly higher psychologic distress scores (p < 0.001), a higher baseline parasympathetic tone (p = 0.003), were unable to increase parasympathetic tone with morphine premedication, had more severe hypotension at the induction of anesthesia (p < 0.001), more episodes of decreases in cerebral saturation (p = 0.0485), and a higher overall complication rate (p = 0.0388) independent of other variables studied. CONCLUSIONS: Patients with diminished autonomic reserves can be identified before cardiac surgery using analysis of HRV and BPV of the response to the Valsalva maneuver, and some evidence suggests that they may be at increased risk of perioperative complications.

Reversal of decreases in cerebral saturation in high-risk cardiac surgery.

OBJECTIVES: To measure the incidence of cerebral desaturation during high-risk cardiac surgery and to evaluate strategies to reverse cerebral desaturation. DESIGN: Prospective observational study followed by a randomized controlled study with 1 intervention group and 1 control group. SETTING: Tertiary care center specialized in cardiac surgery. PARTICIPANTS: All patients were scheduled for high-risk cardiac surgery, 279 consecutive patients in the prospective study and 48 patients in the randomized study. INTERVENTIONS: An algorithmic approach of strategies to reverse cerebral desaturation. In the control group, no attempts were made to reverse cerebral desaturation. MEASUREMENTS AND MAIN RESULTS: Cerebral saturation was measured using near-infrared reflectance spectroscopy. A decrease of 20% from baseline for 15 seconds defined cerebral desaturation. The success or failure of the interventions was noted. Demographic data were collected. Models for predicting the probability and the reversal of cerebral desaturation were based on multiple logistic regressions. In the randomized study, 12 hours of measurements were continued in the intensive care unit without interventions. Differences in desaturation load (% desaturation × time) were compared between groups. Half of the high-risk patients had cerebral desaturation that could be reversed 88% of the time. Interventions resulted in smaller desaturation loads in the operating room and in the intensive care unit. CONCLUSIONS: Cerebral desaturation in high-risk cardiac surgery is frequent but can be reversed most of the time resulting in a smaller desaturation load. A large randomized study will be needed to measure the impact of reversing cerebral desaturation on patient's outcome.

Perioperative Optimization of the Cardiac Surgical Patient.

Perioperative optimization of cardiac surgical patients is imperative to reduce complications, utilize health care resources efficiently, and improve patient recovery and quality of life. Standardized application of evidence-based best practices can lead to better outcomes. Although many practices should be applied universally to all patients, there are also opportunities along the surgical journey to identify patients who will benefit from additional interventions that will further ameliorate their recovery. Enhanced recovery programs aim to bundle several process elements in a standardized fashion to optimize outcomes after cardiac surgery. A foundational concept of enhanced recovery is attaining a better postsurgical end point for patients, in less time, through achievement and maintenance in their greatest possible physiologic, functional, and psychological state. Perioperative optimization is a broad topic, spanning multiple phases of care and involving a variety of medical specialties and nonphysician health care providers. In this review we highlight a variety of perioperative care topics, in which a comprehensive approach to patient care can lead to improved results for patients, providers, and the health care system. A particular focus on patient-centred care is included. Although existing evidence supports all of the elements reviewed, most require further improvements in implementation, as well as additional research, before their full potential and usefulness can be determined.

Opioid Induced Hyperalgesia, a Research Phenomenon or a Clinical Reality? Results of a Canadian Survey.

BACKGROUND: Very little is known regarding the prevalence of opioid induced hyperalgesia (OIH) in day to day medical practice. The aim of this study was to evaluate the physician's perception of the prevalence of OIH within their practice, and to assess the level of physician's knowledge with respect to the identification and treatment of this problem. METHODS: An electronic questionnaire was distributed to physicians who work in anesthesiology, chronic pain, and/or palliative care in Canada. RESULTS: Of the 462 responses received, most were from male (69%) anesthesiologists (89.6%), in the age range of 36 to 64 years old (79.8%). In this study, the suspected prevalence of OIH using the average number of patients treated per year with opioids was 0.002% per patient per physician practice year for acute pain, and 0.01% per patient per physician practice year for chronic pain. Most physicians (70.2%) did not use clinical tests to help make a diagnosis of OIH. The treatment modalities most frequently used were the addition of an NMDA antagonist, combined with lowering the opioid doses and using opioid rotation. CONCLUSIONS: The perceived prevalence of OIH in clinical practice is a relatively rare phenomenon. Furthermore, more than half of physicians did not use a clinical test to confirm the diagnosis of OIH. The two main treatment modalities used were NMDA antagonists and opioid rotation. The criteria for the diagnosis of OIH still need to be accurately defined.

Injection of Bupivacaine into the Pleural and Mediastinal Drains: A Novel Approach for Decreasing Incident Pain After Cardiac Surgery - Montreal Heart Institute Experience.

BACKGROUND: We conducted a chart review of prospectively collected data in order to demonstrate the safety and efficacy of an innovative technique of pleural and mediastinal drain injections. METHODS: Patients who had undergone cardiac surgery and who continued to have pain despite the use of a multimodal pain protocol received injections of 20 mL of 0.25% bupivacaine in pleural and/or mediastinal chest drainage tubes. RESULTS: Patients were evaluated for the incidence mediastinitis, osteitis, and deep sternal wound infection as well as the speed and intensity of pain relief. The odds ratio of infection in the infused group was 0.955 (CI = 0.4705, 1.9384). The adjusted mean "decrease in pain" was 4.01 (SEM = 0.15 and 95% CI = 3.78, 4.38), using the 11-point Likert Numerical Rating Scale. The mean adjusted "time to maximum pain relief" was 8.33 minutes (SEM = 0.42 and 95% CI = 7.50, 9.15). CONCLUSION: This technique is a powerful, safe, and efficient tool in the armamentarium of pain management and its growing use within our institution has provided a substantial benefit in the treatment of early post-operative pain.

Relative frequency and risk factors for long-term opioid therapy following surgery and trauma among adults: a systematic review protocol.

BACKGROUND: When patients have been on opioid therapy for more than 90 days, more than half of them continue using opioids years later. Knowing that long-term opioid consumption could lead to harmful side effects including misuse, abuse, and addiction, it is important to understand the risks of transitioning to prolonged opioid therapy to reduce its occurrence. Perioperative and trauma contexts are ideal models commonly used to study such transition. Long-term use of opioids might be associated with transformation of acute pain to chronic, which might be an example of a risk factor. The objectives of this knowledge synthesis are to examine the relative frequency and the risk factors for transitioning to long-term opioid therapy among patients who have undergone a surgical procedure or experienced a trauma. METHODS: The proposed study methodology is based on Preferred ReportIng Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) statements on the conduct of systematic review and meta-analysis, the MOOSE Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies, and the Cochrane Handbook for Systematic Review of Interventions. A systematic literature search will include multiple databases: Cochrane Central, EMBASE, MEDLINE, PsycINFO, CINHAL, PubMed, and the grey literature. We will identify studies related to opioid use beyond acute/subacute pain control after surgery or trauma. Two of the reviewers will screen all retrieved articles for eligibility and data extraction then critically appraise all identified studies. We will compile a narrative synthesis of all results and conduct a meta-analysis when feasible. As available data permits, we will perform a subgroup analysis of vulnerable populations. DISCUSSION: This systematic review will contribute to the prevention and harm reduction strategies associated with prescription opioids by identifying risk factors leading to the unwarranted long-term opioid therapy. The identification of common risk factors for long-term opioid therapy will help to orient further research on pain management as well as offer key therapeutic targets for the development of strategies to prevent prolonged opioid use. SYSTEMATIC REVIEW REGISTRATION: This protocol was registered in PROSPERO on March 2, 2018; registration number CRD42012018089907 .

Low-dose intravenous ketamine for postcardiac surgery pain: Effect on opioid consumption and the incidence of chronic pain.

BACKGROUND: Recent meta-analyses have concluded that low-dose intravenous ketamine infusions (LDKIs) during the postoperative period may help to decrease acute and chronic postoperative pain after major surgery. AIMS: This study aims to evaluate the level of pain at least 3 months after surgery for patients treated with a postoperative LDKI versus patients who were not treated with a postoperative LDKI. METHODS: Administrative and Ethics Board approval were obtained for this study. We performed a retrospective chart review for all patients receiving LDKI, and equal number of age-, sex-, and surgery-matched patients who did not receive LDKI. Low-dose ketamine was prepared using 100 mg of ketamine in 100 ml of normal saline and run between 50 and 200 mcg/kg/h. RESULTS: We reviewed 115 patients with LDKI and 115 without LDKI. The average age was 63.1 years, 73% of the patients were men and sex was evenly distributed between LDKI and non-LDKI. The average duration of the ketamine infusions was 26.8 h with the average dose being 169.9 mg. At an average of 9 months after surgery, 42% of the ketamine group and 38% of the nonketamine group stated that they had had pain on discharge. Of these patients, 30% of the ketamine group and 26% of the nonketamine group still had pain at the time of the phone call. Women in both groups had more acute and chronic pain than men. CONCLUSION: These results show that LDKI does not promote a decrease in long-term postoperative pain.

A new application of sound resonance technology therapy for the treatment of fibromyalgia: a retrospective analysis.

OBJECTIVE: Chart review to evaluate the effectiveness of a three-phase sound resonance technology therapy (SRTT) protocol for the treatment of fibromyalgia. RESULTS: Initial FIQ scores of 159 consecutive patients ranged from 24 to 80 (mean=58). After Phase 1, ( approximately 1 month into the protocol), FIQ scores had decreased on average by 26 points (n=128, 95% CI 23-30, p<.001). After phase 3 of the protocol 53 patients completed an FIQ questionnaire and the mean decrease in FIQ score was 38 points (95% CI 32-44, p=.004). CONCLUSIONS: This retrospective analysis suggests considerable and rapid relief of the symptoms of fibromyalgia following the use of the three-phase SRTT treatment protocol, which appears to be maintained over several years. Although these results are not conclusive they are remarkable as no other therapy reported in the scientific literature seems as efficacious for fibromyalgia. A follow-up study using an RCT design is warranted.