Quantification of muscle tone by using shear wave velocity during an anaesthetic induction: a prospective observational study.

OBJECTIVES: The quantitative assessment of muscle stiffness or weakness is essential for medical care. Shear wave elastography is non-invasive ultrasound method and provides quantitative information on the elasticity of soft tissue. However, the universal velocity scale for quantification has not been developed. The aim of the study is to determine the shear wave velocities of abdominal muscle during anesthetic induction and to identify methods to cancel the effects of confounders for future development in the quantitative assessment of muscle tone using the universal scale. METHODS: We enrolled 75 adult patients undergoing elective surgery with ASA-PS I - III in the period between December 2018 and March 2021. We measured and calculated the shear wave velocity (SWV) before and after opioid administration (i.e., the baseline at rest and opioid-induced rigidity condition), and after muscle relaxant administration (i.e., zero reference condition). The SWV value was adjusted for the subcutaneous fat thickness by our proposed corrections. The SWVs after the adjustment were compared among the values in baseline, rigidity, and relaxation using one-way repeated-measures ANOVA and post hoc Tukey-Kramer test. A p-value of < 0.05 was considered to be statistically significant. UMIN Clinical Trials Registry identifier UMIN000034692, registered on October 30, 2018. RESULTS: The SWVs in the baseline, opioid-induced rigidity, and muscle relaxation conditions after the adjustment were 2.08 ± 0.48, 2.41 ± 0.60, and 1.79 ± 0.30 m/s, respectively (p < 0.001 at all comparisons). CONCLUSION: The present study suggested that the SWV as reference was 1.79 m/s and that the SWVs at rest and opioid-induced rigidity were ~ 10% and ~ 30% increase from the reference, respectively. The SWV adjusted for the subcutaneous fat thickness may be scale points for the assessment of muscle tone.

Effects of oxytocin on responses to nociceptive and non-nociceptive stimulation in the upper central nervous system.

Oxytocin is known as a social bonding hormone, but it also functions as an anxiolytic or analgesic neurotransmitter. When oxytocin regulates pain or anxiousness centrally as a neurotransmitter, it is secreted by neurons and directly projected to targeted regions. Although the function of oxytocin at the spinal level is well studied, its effects at the supraspinal level are poorly understood. We aimed to investigate the effect of oxytocin at the supraspinal level in vivo using C57BL/6J (wild-type [WT]), oxytocin-deficient (Oxt-/-), oxytocin receptor-deficient (Oxtr-/-), and oxytocin receptor-Venus (OxtrVenus/+) mice lines. Response thresholds in Oxtr-/- mice in Hargreaves and von-Frey tests were significantly lower than those in WT mice, whereas open field and light/dark tests showed no significant differences. Moreover, response thresholds in Oxt-/- mice were raised to those in WT mice after oxytocin administration. Following the Hargreaves test, we observed the co-localisation of c-fos with Venus or the oxytocin receptor in the periaqueductal gray (PAG), medial amygdala (MeA), and nucleus accumbens (NAc) regions in OxtrVenus/+ mice. Furthermore, in the PAG, MeA, and NAc regions, the co-localisation of oxytocin with c-fos and gamma-aminobutyric acid was much stronger in Oxtr-/- mice than in WT mice. However, following von-Frey test, the same findings were observed only in the MeA and NAc regions. Our results suggest that oxytocin exerts its analgesic effect on painful stimulation via the PAG region and a self-protective effect on unpleasant stimulation via the MeA and NAc regions.

Aortic valve replacement in a 41-year-old woman with uncorrected tetralogy of Fallot, pulmonary atresia, and major aortopulmonary collateral arteries: a case report.

BACKGROUND: Tetralogy of Fallot (TOF) is a complex cyanotic congenital heart disease. As most patients with TOF undergo palliative or radical surgical repair during childhood, cardiac surgery under cardiopulmonary bypass (CPB) for adult survivors with unrepaired TOF is exceedingly rare. CASE PRESENTATION: A 41-year-old woman with unrepaired TOF, pulmonary atresia (PA), and major aortopulmonary collateral arteries (MAPCAs) developed acute infectious endocarditis (IE). As vegetation gradually increased despite intravenous antibiotic administration, she was scheduled for urgent aortic valve replacement under CPB. Pulmonary blood flow was primarily provided by the MAPCAs originating from the descending aorta. Intra-aortic balloon occlusion for MAPCAs was performed to ensure a bloodless surgical field. Aortic valve replacement was successful. CONCLUSION: An adult with uncorrected TOF developed acute IE and subsequently had successful cardiac surgery under CPB. Understanding TOF physiology with PA and MAPCAs, particularly pulmonary blood flow through MAPCAs, is crucial.

Sevoflurane administration from extracorporeal membrane oxygenation via the AnaConDa device for a patient with COVID-19: A breakthrough solution for the shortage of intravenous anesthetics.

One of the major issues encountered during the coronavirus disease 2019 (COVID-19) pandemic has been the shortage of intravenous anesthetics. Moreover, patients undergoing extracorporeal membrane oxygenation (ECMO) need large quantities of intravenous anesthetics for sedation. We report the case of a 52-year-old man who was admitted to our hospital due to acute respiratory distress syndrome by COVID-19 and treated with ECMO. As controlling sedation with intravenous anesthetics was challenging, we attempted to administer inhaled anesthetics via the gas flow of ECMO. We decreased the quantity of intravenous anesthetics and opioids. This method might help overcome the shortage of intravenous anesthetics.

Sonoclot® predicts operation time and blood loss after cardiopulmonary bypass in children.

Background: As the circulating blood volume is relatively small in pediatric patients, blood components are quickly lost when bleeding, which make it more difficult to stop the bleeding. Particularly in pediatric cardiac surgery, loss of clotting factors associated with cardiopulmonary bypass (CPB) would likely to be prominent. As a result, bleeding is further promoted and the operation time is extended. In order to search for the relation between clotting factors and the amount of bleeding, we used a viscoelastic point of care test. Objectives: We used Sonoclot® as viscoelastic point of care test to evaluate coagulation function before CPB and before weaning from CPB in pediatric cardiac surgery. Design: Retrospective. Setting: Single-institutional. Participants: We included 55 pediatric patients (median age 13 months [IQR 5-32]) who underwent cardiac surgery under CPB from December 2015 to November 2016. Interventions: None. Measurements and main results: Sonoclot® analysis was performed after induction of anesthesia (pre-data, or baseline data) and before any heparinized saline was given, and right after modified ultrafiltration after weaning from CPB (post-data). Post-data was compared with post-CPB operation time and post-CPB blood loss by multiple regression analysis. Furthermore, effects of fresh frozen plasma (FFP) added on CPB on coagulation function and post-platelet function (describe as PFSC) was assessed. Activated coagulation time (describe as ACTSC) and clot rate (describe as CRSC) showed no significant change between baseline data and post-data. Post-PFSC was worsened by prolonged CPB time (p < 0.05) and correlated to bleeding amount and operation time after CPB (p < 0.05). Total amount of platelet concentrate (PC) transfused was higher in patients with smaller PFSC (p < 0.05). Total amount of FFP and PC transfused correlated with bleeding amount and operation time after CPB (p < 0.05). In the subgroup analysis, PFSC declined in the FFP-included group, whereas there was no significant difference in coagulation function. Addition of FFP to CPB did not significantly affect CR, whereas PFSC deteriorated as CPB time was prolonged (CPB time = 1/(0.0021∗PFSC + 0.0055)). Conclusion: Sonoclot® is useful to evaluate coagulation function in pediatric patients who undergo CPB. Preventive administration of FFP or PC in CPB circuit could reduce bleeding after CPB.