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Alexander D Stoker,1 David M Rosenfeld,1 Matthew R Buras,2 Jeremy M Alvord,1 Andrew W Gorlin1 1Department of Anesthesiology and Perioperative Medicine, Mayo Clinic Arizona, Phoenix, AZ, USA; 2Mayo Clinic Arizona, Phoenix, AZ, USACorrespondence: Alexander D StokerDepartment of Anesthesiology and Perioperative Medicine, Mayo Clinic Arizona, 5777 E Mayo Blvd, Phoenix, AZ 85054, USATel +1 480-510-7933Email Stoker.Alexander@mayo.eduIntroduction: Sub-anesthetic ketamine is frequently used as an analgesic to reduce perioperative opioid consumption and has also been shown to have antidepressant effects. Side effects of ketamine include dizziness, diplopia, nystagmus, and psychomimetic effects. It is unclear what clinical factors may be associated with ketamine-related adverse drug events (ADEs).Methods: We performed a retrospective review of 95 patients who received sub-anesthetic ketamine infusions at our institution. Data examined associations between ketamine-related ADEs and various clinical characteristics including chronic pain, depression, or psychiatric disorder, patient physical characteristics, chronic opioid use, perioperative opioid use, dose and duration of ketamine infusions, pain scores, and perioperative medications such as serotonergic agents, central nervous system (CNS) depressants, and analgesics.Results: Overall incidence of ketamine-related ADEs was 29.5% and the incidence of psychomimetic effects was 14.8%. We observed that patients with a history of depression have a lower incidence of ketamine-related ADEs compared to patients without a history of depression (10.3% vs 37.3%; p value = 0.007).Conclusion: Patients with depression were found to have a statistically significant reduction in the incidence of ketamine-related ADEs. We found no statistically significant positive associations between ketamine-related ADEs and other clinical factors such as a history of chronic pain, psychiatric disease, patient physical characteristics, perioperative opioid use, dose of ketamine infusion, or co-administration of other CNS depressants.Keywords: ketamine, pain, depression, adverse, drug-event

Andrew W Gorlin, David M Rosenfeld, Jillian Maloney, Christopher S Wie, Johnathan McGarvey, Terrence L Trentman Department of Anesthesiology, Mayo Clinic Arizona, Phoenix, AZ, USA Abstract: The conversion of high-dose intravenous (IV) opioids to an equianalgesic epidural (EP) or intrathecal (IT) dose is a common clinical dilemma for which there is little evidence to guide practice. Expert opinion varies, though a 100 IV:10:EP:1 IT conversion ratio is commonly cited in the literature, especially for morphine. In this study, the authors surveyed 724 pain specialists to elucidate the ratios that respondents apply to convert high-dose IV morphine, hydromorphone, and fentanyl to both EP and IT routes. Eighty-three respondents completed the survey. Conversion ratios were calculated and entered into graphical scatter plots. The data suggest that there is wide variation in how pain specialists convert high-dose IV opioids to EP and IT routes. The 100 IV:10 EP:1 IT ratio was the most common answer of survey respondent, especially for morphine, though also for hydromorphone and fentanyl. Furthermore, more respondents applied a more aggressive conversion strategy for hydromorphone and fentanyl, likely reflecting less spinal selectivity of those opioids compared with morphine. The authors conclude that there is little consensus on this issue and suggest that in the absence of better data, a conservative approach to opioid conversion between IV and neuraxial routes is warranted. Keywords: intrathecal pump, epidural, cancer pain

The estimation of surgical blood loss is routinely performed during and after surgical procedures and has morbidity and mortality implications related to the risk of under- and over-resuscitation. The strategies for estimating surgical blood loss include visual estimation, the gravimetric method, the colorimetric method, formula-based methods, and other techniques (e.g., cell salvage). Currently, visual estimation continues to be the most widely used technique. In addition, unique considerations exist when these techniques are applied to various clinical settings such as massive transfusion, cardiac surgery, and obstetrics. Ultimately, when using estimated surgical blood loss to guide perioperative fluid management and transfusion thresholds, it is also important to mitigate the risks associated with resuscitation by targeting a goal-directed fluid therapy approach by utilizing markers of fluid-responsiveness to optimize stroke volume (cardiac output) and delivery of oxygen., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)

Background: During orthotopic liver transplantation, allograft reperfusion is a dynamic point in the operation and often requires vasoactive medications and blood transfusions. Normothermic machine perfusion (NMP) of liver allografts has emerged to increase the number of transplantable organs and may have utility during donation after circulatory death (DCD) liver transplantation in reducing transfusion burden and vasoactive medication requirements., Methods: This is a single-center retrospective study involving 226 DCD liver transplant recipients who received an allograft transported with NMP (DCD-NMP group) or with static cold storage (DCD-SCS group). Veno-venous bypass was not used in any patients. Infusion doses of norepinephrine, epinephrine, and vasopressin as well as bolus doses of vasoactive medications during reperfusion were recorded. Blood component therapy was recorded according to phase of liver transplantation and during the first 24 hours postprocedure., Results: A total of 103 recipients in the DCD-NMP group and 123 patients in the DCD-SCS group were included. Post-reperfusion syndrome (PRS) incidence was reduced in the DCD-NMP group compared to the DCD-SCS group (10.7% [95% confidence interval, CI, 5.5%-18.3%] vs 42.3% [95% CI, 33.4%-51.5%]; P < .001). During the reperfusion period, patients in the DCD-SCS group required increased bolus doses of epinephrine and vasopressin compared to the DCD-NMP group (24.6 vs 7.5 µg; P < .001) and (5.4 vs 2.4 units; P < .001), respectively. The DCD-SCS group received a higher infusion dose of epinephrine during anhepatic phase, at reperfusion, and up to 90 minutes after reperfusion. In the postreperfusion period, there were significant increases in the transfusion of red blood cells (RBCs; 5.3 vs 3.7 units; P = .006), fresh frozen plasma (FFP; 3.4 vs 1.9 units; P < .001), cryoprecipitate (2.7 vs 1.8 pooled units; P = .015) and platelets (0.9 vs 0.4 units; P = .008) in the DCD-SCS group compared to the DCD-NMP group. During the first 24 hours postprocedure, transfusion of RBCs, FFP, and cryoprecipitate in the DCD-SCS group was increased compared to the DCD-NMP group ([2.6 vs 1.7 units; P = .028], [1.6 vs 0.8 units; P < .001], [1.5 vs 0.9 pooled units; P = .031]) respectively. Administration of tranexamic acid was more frequent in the DCD-SCS group during the post-reperfusion period compared to the DCD-NMP group (13% [95% CI, 5.7%-17.4%] vs 3.9% [95% CI, 1.1%-9.6% 95%]; P = .018)., Conclusions: In DCD liver transplantation, use of NMP was associated with reduced incidence of PRS and decreased vasopressor and inotrope requirements at the time of allograft reperfusion compared to using SCS. Additionally, NMP was associated with reduced transfusion of all blood product components as well as antifibrinolytic agent administration in the post-reperfusion period. Reduced transfusion burden in the DCD-NMP group also occurred during the first 24 hours posttransplant., Competing Interests: Conflicts of Interest, Funding: See Disclosures at the end of the article., (Copyright © 2024 International Anesthesia Research Society.)

Introduction: Obesity is a common comorbidity seen in the perioperative setting and is associated with many diseases including cardiovascular disease and obstructive sleep apnea. Laparoscopic Roux-en-Y gastric bypass is the gold standard surgical treatment for patients whose weight is refractory to diet and exercise. Caring for these patients perioperatively presents unique challenges to anesthesiologists and is associated with an increased risk of adverse respiratory events. In our study, we hypothesize that a low-dose perioperative ketamine infusion will reduce opioid consumption and improve analgesia when compared to standard therapy., Methods: This is a single-center, prospective randomized controlled study enrolling 35 patients in total. Patients were randomized equally into the ketamine and control group. Preop, intraop, and postop management regimens were standardized. The ketamine group received a 0.3 mg/kg ideal body weight ketamine bolus after induction followed by a 0.2 mg/kg/hr ketamine infusion continued into the postop setting for up to 24 hours. Data collected included total perioperative opioids used converted to oral morphine equivalents (ME), pain scores, side effects, hospital length of stay, and patient satisfaction captured via postoperative questionnaires., Results: The use of perioperative opioid consumption was significantly lower in the ketamine group when compared with the control group (179.9 ME versus 248.7 ME, P =0.03). There was no statistically significant difference in pain scores or hospital length of stay postoperatively between the two groups. There were also no reported adverse respiratory events, prolonged sedation, agitation, or other side effects reported in either group. The patient satisfaction questionnaires showed a significant difference with the ketamine group reporting lower maximum pain scores, a decrease in how pain limited activities of daily living once discharged, and increased hospital pain management satisfaction scores., Conclusions: Perioperative low-dose ketamine infusions significantly reduced opioid consumption in morbidly obese patients undergoing laparoscopic gastric bypass surgery., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Mitchell T. Seman et al.)

Background: Utilization of intraoperative transesophageal echocardiography (TEE) during orthotopic liver transplantation (OLT) is expanding annually in high-volume transplant centers. During OLT intraoperative TEE is used to gather real-time information on cardiovascular function and intravascular volume status. Although standardized TEE views exist, there are nontraditional views described in the literature which have the potential to diagnose evolving pathology and define normal variants of hepatic vasculature., Methods: A literature review was completed utilizing the PubMed database for English-only, peer-reviewed publications discussing nontraditional use of intraoperative TEE during OLT and hepatic vascular-related surgeries from 2009 to 2019. Both case reports and review articles were considered., Results: The PubMed literature search offered 8 publications for analysis, including 7 case reports and 1 article review, revealing several nontraditional TEE views not included in a comprehensive transesophageal echocardiographic examination. These nontraditional views were generally obtained using modifications to the transgastric and bicaval views to visualize liver vasculature. We present the various techniques for obtaining these views from the 8 articles identified., Conclusions: At high-volume transplant centers, TEE use during OLT is increasing. Intraoperative TEE is a valuable tool to assess hepatic vascular structures critical to allograft/organ function without interruption of the surgical procedure. Nontraditional use of TEE to diagnose intraoperative noncardiac pathology in OLT appears underutilized and underreported. The modified hepatic and modified transgastric views we describe can be used to evaluate hepatic vasculature, influence surgical decision-making and ultimately improve patient care., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2020 The Author(s). Transplantation Direct. Published by Wolters Kluwer Health, Inc.)

Background and Aims: There are limited data on the effect of ampule size on drug dosing. The objective of this study is to determine the effect of ampule size on perioperative opioid dosing and post-anesthesia care unit (PACU) outcomes., Material and Methods: This was a retrospective review of patients undergoing robotically assisted laparoscopic radical prostatectomy before and after a 5-ml fentanyl ampule was discontinued. The primary outcome was intraoperative opioid administration divided into fentanyl at induction of anesthesia, total fentanyl, and total opioid. Secondary outcomes observed in PACU included the opioid administered, visual analog scale (VAS) pain scores, postoperative nausea and vomiting, and length of stay in PACU., Results: A total of 100 patients (50 PRE and 50 POST) were included. In the intraoperative opioid administration, mean (SD) of fentanyl at induction was 117.0 (49.3) in PRE group and 85.0 (35.4) μg in POST group ( P < 0.01). The total fentanyl requirement was 247.0 (31.0) in PRE group and 158.5 (85.1) μg in POST group ( P < 0.01). The total opioid in intravenous morphine equivalents (IVME) was 34.1 (5.8) in PRE group and 23.2 (6.8) mg in POST group ( P < 0.01). Among the secondary outcomes, mean (SD) of IVME of opioid was 7.7 (8.2) in PRE group and 9.9 (8.1) mg in POST group ( P = 0.18). The VAS pain score on arrival was 0.7 (1.4) in PRE group and 3.8 (3.3) in POST group ( P < 0.01). The cumulative VAS pain score was 2.3 (2.0) in PRE group and 3.3 (2.2) in POST group ( P < 0.01). The length of stay was significantly more in POST group, 193.8 (75.8) minutes, as compared with PRE group, 138.6 (61.0) minutes ( P < 0.01)., Conclusions: A change in the ampule size significantly affected intraoperative dosing, PACU pain scores, and PACU length of stay in patients undergoing robotically assisted laparoscopic radical prostatectomy under general anesthesia. This was explained by clinician's desire to conserve the drug and avoid the complex process of narcotic waste disposal., Competing Interests: There are no conflicts of interest.

This randomised, double-blind, placebo-controlled study compared the effect of perineural with intravenous dexamethasone, both administered concomitantly with interscalene brachial plexus block for shoulder surgery. Patients received 8 mg dexamethasone mixed with ropivacaine in the block injection (n = 42), 8 mg dexamethasone intravenously at the time of the block (n = 37), or intravenous saline (n = 41) at the time of the block. Perineural and intravenous dexamethasone resulted in prolonged mean (SD) duration of block to 16.9 (5.2) h and 18.2 (6.4) h, respectively, compared with 13.8 (3.8) h for saline (p = 0.001). Mean (SD) opioid consumption (morphine equivalents) during the first 24 h after postanaesthesia recovery arrival was 12.2 (9.3) mg in the perineural dexamethasone, 17.1 (15.9) mg in the intravenous dexamethasone and 24.1 (14.3) mg in the saline groups (p = 0.001). Dexamethasone via either route reduced anti-emetic use (p = 0.046). There was no effect on patient satisfaction. These results suggest that both perineural and intravenous dexamethasone are useful adjuncts to ropivacaine interscalene block, with the intravenous route preferred as this avoids the possibility of neural toxicity of dexamethasone., (© 2016 The Association of Anaesthetists of Great Britain and Ireland.)

Ketamine, an N-methyl-d-aspartate antagonist, blunts central pain sensitization at sub-anesthetic doses (0.3 mg/kg or less) and has been studied extensively as an adjunct for perioperative analgesia. At sub-anesthetic doses, ketamine has a minimal physiologic impact though it is associated with a low incidence of mild psychomimetic symptoms as well as nystagmus and double vision. Contraindications to its use do exist and due to ketamine's metabolism, caution should be exercised in patients with renal or hepatic dysfunction. Sub-anesthetic ketamine improves pain scores and reduces perioperative opioid consumption in a broad range of surgical procedures. In addition, there is evidence that ketamine may be useful in patients with opioid tolerance and for preventing chronic postsurgical pain.

Introduction: Sexual dysfunction is a well-known side effect of antidepressants. Painful ejaculation is a rare side effect that has been reported with the use of some psychiatric drugs such as triclyclic antidepressants. Cyclobenzaprine is a muscle relaxant that is structurally similar to tricyclic antidepressants. It is the most commonly prescribed muscle relaxant in the United States and accounts for 18% of all prescriptions written for chronic back pain., Methods: A 55-year-old man was referred to our pain medicine clinic for evaluation and treatment of pain with ejaculation., Main Outcome Measure: The main outcome measure was to review the current published literature and case reports on painful ejaculation from medication use, in particular tricyclic antidepressants., Results: After discontinuation of cyclobenzaprine, our patient's sexual dysfunction resolved. This result was consistent with the literature reviewed on the topic., Conclusion: Painful ejaculation is likely an underreported side effect of tricyclic antidepressants and cyclobenzaprine use. Fortunately, these symptoms are reversible and discontinuation of these medications is typically an effective cure. K raus MB , W ie CS , G orlin AW , W isenbaugh ES , and R osenfeld DM . Painful ejaculation with cyclobenzaprine: A case report and literature review. S ex M ed 2015;3:343-345.

Objectives: Patient satisfaction is tied to outcome, but there is scant literature on the relationship of patient perceived outcome and attributes of the pain clinic visit, including the patient interaction with the pain management specialist. The primary purpose of this study is to identify attributes of the patient-provider interaction most strongly associated with patient perceived outcome of their clinic visit. The secondary aim is to correlate patient perceived outcome with patient self-rated overall health., Methods: A patient satisfaction survey conducted via phone approximately 3 weeks after the patient's pain clinic visit., Results: The response rate was 60.2%; 987 patient surveys collected between 2006 and 2010 were used in the analysis. Four factors were significantly associated with the outcome: (1) Explanations by the physician of the patient's condition and treatment, (2) clear instructions regarding post-appointment activities, (3) knowing the patient as a person, and (4) the patient's self-rated health. In terms of the secondary objective, those who answered very good/excellent regarding their self-rated health had an 87% increased odds of better (very good/excellent) outcome of their pain clinic visit (or 1.87 times the odds of better outcome) compared with those who answered poor/fair/good., Conclusions: Our results suggest that pain physicians may positively impact patient perceived outcomes of clinic visits by explaining the patient's condition and treatment, providing instructions, and taking the time to understand the patient and their values., (© 2013 World Institute of Pain.)

The transversus abdominis plane (TAP) block is a relatively new regional anesthesia technique that provides analgesia to the parietal peritoneum as well as the skin and muscles of the anterior abdominal wall. It has a high margin of safety and is technically simple to perform, especially under ultrasound guidance. A growing body of evidence supports the use of TAP blocks for a variety of abdominal procedures, yet, widespread adoption of this therapeutic adjunct has been slow. In part, this may be related to the limited sources for anesthesiologists to develop an appreciation for its sound anatomical basis and the versatility of its clinical application. As such, we provide a brief historical perspective on the TAP block, describe relevant anatomy, review current techniques, discuss pharmacologic considerations, and summarize the existing literature regarding its clinical utility with an emphasis on recently published studies that have not been included in other systematic reviews or meta-analyses.