Minimum alveolar concentration-awake of Xenon alone and in combination with isoflurane or sevoflurane

BACKGROUND: The minimum alveolar concentration (MAC)-awake is a traditional index of hypnotic potency of an inhalational anesthetic. The MAC-awake of xenon, an inert gas with anesthetic properties (MAC = 71%), has not been determined. It is also unknown how xenon interacts with isoflurane or sevoflurane on the MAC-awake. METHODS: In the first part of the study, 90 female patients received xenon, nitrous oxide (N2O), isoflurane, or sevoflurane supplemented with epidural anesthesia (n = 36 for xenon and n = 18 per group for other anesthetics). In the second part, 72 additional patients received either xenon or N2O combined with the 0.5 times MAC-awake concentration of isoflurane or sevoflurane (0.2% and 0.3%, respectively, based on the results of the first part; n = 18 per group). During emergence, the concentration of an assigned anesthetic (xenon or N2O only in the second part) was decreased in 0. 1 MAC decrements every 15 min from 0.8 MAC or from 70% in the case of N2O until the patient followed the command to either open her eyes or to squeeze and release the investigator's hand. The concentration midway between the value permitting the first response to command and that just preventing it was defined as the MAC-awake. RESULTS: The MAC-awake were as follows: xenon, 32.6 +/- 6.1% (mean +/- SD) or 0.46 +/- 0.09 MAC; N2O, 63.3 +/- 7.1% (0.61 +/- 0.07 MAC); isoflurane, 0.40 +/- 0.07% (0.35 +/- 0.06 MAC); and sevoflurane, 0.59 +/- 0.10% (0.35 +/- 0.06 MAC). Addition of the 0.5 MAC-awake concentrations of isoflurane and sevoflurane reduced the MAC-awake of xenon to 0.50 +/- 0.15 and 0.51 +/- 0.16 times its MAC-awake as a sole agent, but that of N2O to the values significantly greater than 0.5 times its MAC-awake as a sole agent (0.68 +/- 0.12 and 0.66 +/- 0.14 times MAC-awake; P < 0.01, analysis of variance and Dunnett's test). CONCLUSIONS: The MAC-awake of xenon is 33% or 0.46 times its MAC. In terms of the MAC-fraction, this is smaller than that for N2O but greater than those for isoflurane and sevoflurane. Unlike N2O, xenon interacts additively with isoflurane and sevoflurane on MAC-awake.     

Plasma concentration of fentanyl with xenon to block somatic and hemodynamic responses to surgical incision

BACKGROUND: Although anesthesia with xenon has been supplemented with fentanyl, its requirement has not been established. This study was conducted to determine the plasma concentrations of fentanyl necessary to suppress somatic and hemodynamic responses to surgical incision in 50% patients in the presence of 0.7 minimum alveolar concentration (MAC) xenon. METHODS: Twenty-five patients were allocated randomly to predetermined fentanyl concentration between 0.5 and 4.0 ng/ml during 0.7 MAC xenon anesthesia. Fentanyl was administered using a pharmacokinetic model-driven computer-assisted continuous infusion device. At surgical incision each patient was monitored for somatic and hemodynamic responses. A somatic response was defined as any purposeful bodily movement. A positive hemodynamic response was defined as a more than 15% increase in heart rate or mean arterial pressure more than the preincision value. The concentrations of fentanyl to prevent somatic and hemodynamic responses in 50% of patients were calculated using logistic regression. RESULTS: The concentration of fentanyl to prevent a somatic response to skin incision in 50% of patients in the presence of 0.7 MAC xenon was 0.72 +/- 0.07 ng/ml and to prevent a hemodynamic response was 0.94 +/- 0.06 ng/ml. CONCLUSIONS: Comparing these results with previously published results in the presence of 70% nitrous oxide, the fentanyl requirement in xenon anesthesia is smaller than that in the equianesthetic nitrous oxide anesthesia.     

Applications of the transfibular approach to the hindfoot: A systematic review and description of a preferred technique

BackgroundThe indications and technique for the transfibular approach to the tibiotalar joint have evolved since its initial popularization in 1942. The purpose of this systematic review is to assess the indications, techniques, and postoperative outcomes among procedures performed with the transfibular approach.MethodsA comprehensive search of PubMed, Medline, and Embase databases from 1942 to 2018 was performed in accordance with PRISMA guidelines. After an initial broad search of transfibular approach indications, articles were stratified into 4 major surgical categories for assessment: (1) tibiotalar arthrodesis (2) tibiotalocalcaneal arthrodesis (3) total ankle replacement and (4) distal tibial tumor excision. Data was analyzed according to these 4 categories.ResultsA total of 32 studies (874 ankles) were included. Fibular non-union rates were 0.7 % (5 of 672) across all studies, 0.6% (2 of 329) for tibiotalar arthrodesis, 0.0% (0 of 12) for tibiotalocalcaneal arthrodesis, 1.0 % (3 of 296) for total ankle arthroplasty and 0.0% (0 of 15) for other procedures. Rates of deep infection were 2.5% (23 of 903) across all studies, 3.2% (15 of 466) for tibiotalar arthrodesis, 3.7% (4 of 106) for tibiotalocalcaneal arthrodesis, 1.3% (4 of 296) for total ankle arthroplasty, and 0.0% (0 of 15) for other procedures.ConclusionsThe transfibular approach is useful for cases requiring extensile exposure of the tibiotalar joint. This study provides evidence that the transfibular approach yields satisfactory results, with low complication and infection rates.Level of evidenceIV     

Effect of variable annular reduction on functional tricuspid regurgitation and right ventricular dynamics in an ovine model of tachycardia-induced cardiomyopathy

ObjectiveTo investigate the effect of variable tricuspid annular reduction (TAR) on functional tricuspid regurgitation (FTR) and right ventricular (RV) dynamics in ovine tachycardia-induced cardiomyopathy.MethodsNine adult sheep underwent implantation of a pacemaker with an epicardial lead and were paced at 200 to 240 bpm until the development of biventricular dysfunction and functional TR was noted. During reoperation on cardiopulmonary bypass, 6 sonomicrometry crystals were placed around the tricuspid annulus (TA) and 14 were placed on the RV epicardium. Annuloplasty suture was placed around the TA and externalized to an epicardial tourniquet. After weaning from cardiopulmonary bypass, echocardiographic, hemodynamic, and sonomicrometry data were acquired at baseline and during 5 progressive TARs achieved with suture cinching. TA area and RV free wall strains and function were calculated from crystal coordinates.ResultsAfter pacing, changes in left ventricular (LV) ejection fraction and RV fractional area decreased significantly. Mean TA diameter increased from 25.1 ± 2.9 mm to 31.5 ± 3.3 mm (P = .005), and median TR (range, 0-3+) increased from 0 (0) to 3 (2) (P = .004). Progressive suture cinching reduced the TA area by 18 ± 6%, 38 ± 11%, 56 ± 10%, 67 ± 9%, and 76 ± 8%. Only aggressive annular reductions (67% and 76%) decreased TR significantly, but these were associated with deterioration of RV function and strain. A moderate annular reduction of 56% led to a substantial reduction of TR with little deleterious effect on regional RV function.ConclusionsA moderate TAR of approximately 50% may be most advantageous for correction of functional TR and simultaneous maintenance of regional RV performance. Additional subvalvular interventions may be needed to achieve complete valvular competence.     

Substance use education in US schools of pharmacy: A systematic review of the literature

Background: The authors sought to systematically review the quantity and quality of literature describing substance use disorders (SUDs) education in US schools of pharmacy and determine the effectiveness of the educational interventions employed. Methods: The authors conducted a systematic review of SUDs education studies in US pharmacy schools. All literature database searches were performed on April 30, 2016, in 5 databases: Ovid MEDLINE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Embase.com, ERIC via FirstSearch, and CINAHL via EBSCOhost. The study authors conducted this systematic review according to the Preferred Reporting Items for Systemic Reviews and Meta-analyses guidelines and registered it with PROSPERO, which is an international prospective register of systematic reviews. The PROSPERO registration number is CRD42016037443. The study authors created a modified data extraction sheet based on the Best Evidence in Medical Education coding sheet. A Medical Education Research Study Quality Instrument (MERSQI) score was calculated for included articles. Results: From the 1626 retrieved records, 7 were included in the present review. The studies assessed students’ impressions and abilities regarding SUDs pre- and post-intervention. The mean ± SD MERSQI score of the 7 studies was 9.86 ± 1.21 (range: 8–11.5). The included articles assessed pharmacy students at various academic years, with the majority students in either their first or second year of pharmacy school, and described both required and elective courses. The educational interventions varied in design and outcomes measured. Education included nicotine, alcoholism, and SUDs in general. None of the included articles reported on education regarding opioid use disorders. Conclusions: The studies included in this systematic review demonstrate that teaching pharmacy students about SUDs produces a positive impact in their attitudes and knowledge on this subject.     

Serum vascular endothelial growth factor receptor 3 as a potential biomarker in psoriasis

To discover novel biomarkers of psoriasis, a target‐specific antibody array screening of serum samples from psoriasis patients was initially performed. The results revealed that vascular endothelial growth factor receptor 3 (VEGFR‐3) was significantly elevated in the sera of psoriasis patients, compared to healthy controls. Next, ELISA validation studies in a larger cohort of psoriasis patients (N = 73) were conducted, which confirmed that serum VEGFR‐3 was indeed significantly increased in patients with psoriasis compared to healthy controls (P < 0.001). Furthermore, receiver operating characteristic curve analysis demonstrated that serum VEGFR‐3 exhibited potential in distinguishing healthy controls from psoriasis patients: area under the curve = 0.85, P < 0.001. In addition, serum levels of VEGFR‐3 were correlated with Psoriasis Area Severity Index scores (R = 0.32, P = 0.008) in psoriasis patients. Interestingly, serum VEGFR‐3 levels were significantly elevated in psoriatic arthritis compared to non‐psoriatic arthritis (P = 0.026). A pilot longitudinal study demonstrated that serum levels of VEGFR‐3 could reflect disease progression in psoriasis. Collectively, serum VEGFR‐3 may have a clinical value in monitoring disease activity of psoriasis.     

Ileal dysgenesis coexisting with multiple enteric duplication cysts in a child—MR enterography, CT, and Meckel scan appearances

There are numerous causes of iron deficiency anemia due to gastrointestinal tract bleeding in children. While a very thorough history may elucidate common etiologies, such as cow’s milk protein-induced colitis and nonsteroidal anti-inflammatory drug-related gastritis or peptic ulcer disease, other less frequent causes often present a diagnostic challenge. We present the MR enterography (MRE), CT and Meckel scan findings of ileal dysgenesis coexisting with multiple enteric duplication cysts in a young child who presented with chronic iron deficiency anemia, recurrent gastrointestinal tract bleeding and unexplained bowel perforation. In this case, MRE was able to identify and characterize each individual lesion and directly guide appropriate surgical management.     

Anatomic structures at risk in anteroposterior screw fixation of posterior malleolar fractures: A cadaver study

IntroductionPercutaneous anterior-posterior (AP) screw is an option for posterior malleolus fracture fixation when the fracture fragment can be reduced indirectly by the mean of ligamentotaxis. However, anterior anatomic structures could be injured during screw placement.Materials and methodsEleven below-knee cadavers were employed for the placement of AP screws in an attempt of fixing assumed Haraguchi Type-I posterior malleolar fractures. Three entry points were selected as medial to the anterior tibial tendon (ATT), lateral to the ATT, and lateral to the extensor digitorum longus (EDL). Three AP screws were placed under guidance of fluoroscopy. After dissection, measurements were made (mm) from each screw to nearby structures. Distances were calculated and damage to structures was documented.ResultsMean, minimum, and maximum distances from the medial screw to the greater saphenous vein, TA, EHL, anterior tibial artery (ATA), and deep peroneal nerve (DPN), were 18.1 (12–25) mm, 2.0 (0–5) mm, 13.6 (9–20) mm, 16.6 (9–25) mm, and 20.1 (12–27) mm. From the middle screw to the ATA, DPN, TA, EHL, and EDL, were 1.2 (0–3) mm, 4.9 (3–9) mm, 3.8 (1–7) mm, 0.4 (0–2) mm, and 13.6 (10–18) mm. From the lateral screw to the superficial peroneal nerve (SPN), EDL, DPN, and ATA, were 10.8 (0–16) mm, 1.2 (0–4) mm, 15.9 (11–25) mm, 19 (15–27) mm. The SPN was found partially cut by the lateral screw on 1 specimen.ConclusionsLateral and middle percutaneous AP screw placement put certain anatomic structures at-risk of injury. Medial screw placement did not result in appreciable damage to adjacent structures. Entry point of AP screws should be selected with respect to posterior malleolar fracture and anatomic structures.Level of evidenceIV.     

The Impact of Comprehensive Care for Joint Replacement Bundled Payment Program on Care Delivery

Background

Comprehensive Care for Joint Replacement (CJR) is a Medicare initiative to test the impact of holding a hospital accountable for services provided during an episode of care for a lower extremity joint arthroplasty on costs and quality. This study examines whether hospital participation in CJR is associated with having programs focused on improving posthospitalization care or reducing costs using a survey of orthopedic surgeons.