Crosstalk enables mutual activation of coupled quorum sensing pathways through "jump-start" and "push-start" mechanisms.

Many quorum sensing microbes produce more than one chemical signal and detect them using interconnected pathways that crosstalk with each other. While there are many hypotheses for the advantages of sensing multiple signals, the prevalence and functional significance of crosstalk between pathways are much less understood. We explore the effect of intracellular signal crosstalk using a simple model that captures key features of typical quorum sensing pathways: multiple pathways in a hierarchical configuration, operating with positive feedback, with crosstalk at the receptor and promoter levels. We find that crosstalk enables activation or inhibition of one output by the non-cognate signal, broadens the dynamic range of the outputs, and allows one pathway to modulate the feedback circuit of the other. Our findings show how crosstalk between quorum sensing pathways can be viewed not as a detriment to the processing of information, but as a mechanism that enhances the functional range of the full regulatory system. When positive feedback systems are coupled through crosstalk, several new modes of activation or deactivation become possible.

Perioperative Point-of-Care Ultrasound Use by Anesthesiologists.

Point-of-Care ultrasound (POCUS) is the bedside utilization of ultrasound, in real-time, to aid in the diagnosis and treatment of patients. Image acquisition from POCUS utilization by anesthesiologists involves the assessment of multiple organs in different perioperative situations. POCUS can be utilized to enhance clinical decision-making in a variety of perioperative situations due to its ability to assess endotracheal tube placement, cardiac function, pulmonary function, aspiration risk, hemodynamics, vascular access, and nerve visualization for regional procedures. The mounting clinical evidence for the value of POCUS in perioperative settings, its growing affordability, and its low associated risks are responsible for the nationwide movement across many anesthesiology residency programs to increase the focus on perioperative ultrasound training. The purpose of this review is to present to current anesthesiologists and anesthesiology trainees, a broad discussion regarding the diverse utility and importance of POCUS in perioperative settings.

Comparison of Deep Sedation and General Anesthesia With an Endotracheal Tube for Transcaval Transcatheter Aortic Valve Replacement: A Pioneering Institution's Experience.

OBJECTIVES: Transcaval transcatheter aortic valve replacement (TC-TAVR) is an alternative approach to transcatheter aortic valve replacement involving deployment of the bioprosthetic valve via a conduit created from the inferior vena cava to the descending aorta in patients for whom the traditional transfemoral approach is not feasible. By analyzing the largest known cohort of TC-TAVR patients, the authors wished to compare hospital length of stay and post-procedure outcomes between patients who underwent the procedure under deep sedation (DS) and patients who underwent general anesthesia with an endotracheal tube. DESIGN: Retrospective, single-center study. SETTING: Henry Ford Hospital in Detroit, MI. PARTICIPANTS: Patients undergoing TC-TAVR from 2015 to 2018. MEASUREMENTS AND MAIN RESULTS: Seventy-nine patients were included in the analysis, which consisted of 38 under general anesthesia with an endotracheal tube and 41 under DS. The sample was divided into a general anesthesia (GA) group and DS group. There were no significant differences in implant success rate or post-procedure outcomes, including in-hospital mortality (p = 0.999) and major vascular complication rate (p = 0.481), between the two groups. Patients in the GA group stayed a median of 24 hours longer in the intensive care unit (ICU) (p < 0.001) and one day longer in the hospital (p = 0.046) after the procedure compared to patients in the DS group. The median procedure time was significantly lower (135 minutes) in the DS group compared to the GA group (167 minutes, p < 0.001). CONCLUSIONS: Patients undergoing TC-TAVR under DS had similar postoperative outcomes and shorter post-procedure hospital and ICU lengths of stay compared to general anesthesia. In the authors' experience, DS is the preferred anesthetic technique for TC-TAVR.

Incorporating Perioperative Point-of-Care Ultrasound as Part of the Anesthesia Residency Curriculum.

OBJECTIVE: The purposes of this study were to establish whether implementing a curriculum of perioperative point-of-care ultrasound (POCUS) of the heart and lungs for current in-training anesthesia residents during their required month of cardiac anesthesia was feasible and whether an evaluation tool would demonstrate improvement in the residents' baseline knowledge of POCUS. DESIGN: Single-center, prospective, cohort, and observational study. SETTING: A tertiary-care, university-affiliated hospital. PARTICIPANTS: The study comprised 16 anesthesia residents on their third postgraduate training year during their required cardiac anesthesia rotation. INTERVENTIONS: The implementation of a curriculum to educate anesthesia residents in perioperative POCUS of the heart and lungs on patients undergoing elective cardiothoracic procedures that included both theoretical and practical approaches. A 21-question, multiple-choice, electronic-generated test was developed to gauge performance improvement from before ("pretest") to after ("posttest") the 4-week period. MEASUREMENTS AND MAIN RESULTS: Of the 16 residents, 13 (81.3%) showed improved scores between the pretest and posttest periods after the 4-week rotation. The difference between pretest and posttest mean score was 5 (p = 0.001). CONCLUSIONS: This study demonstrates that integrating a curriculum dedicated to perioperative POCUS of the heart and lungs as part of the goals and objectives during the rotation of cardiac anesthesia is feasible and that anesthesia residents who received the training proposed by the authors improved their cognitive and technical skills.

Anesthetic implications for coexisting cardiac capillary hemangioma and multiple coronary artery to pulmonary artery fistulas.

Abnormalities of the coronary vascular branches and cardiac hemangiomas represent together unusual clinical entities, with an incidence difficult to establish for the former as the vast majority of the patients with these anomalous vascular connections are usually asymptomatic and 2.8% for the latter. Symptomatic patients may develop dyspnea on exertion or chest pain secondary to a "coronary steal" phenomenon as part of the underlying pathophysiology of the disease. The authors report a case of a patient with concomitant cardiac capillary hemangioma with multiple coronary to pulmonary artery fistula connections that was successfully treated with surgical resection of the tumor and ligation of the fistula tracts. A comprehensive and balanced anesthesia management aimed to preserve tight hemodynamic stability to avoid increased myocardial demand and worsening of the coronary steal becomes essential in these patients.