Ultrasound Shear Wave Elastography Evaluation of the Liver and Implications for Perioperative Medicine.

Ultrasound shear wave elastography (SWE) is a non-invasive, low risk technology allowing the assessment of tissue stiffness. Used clinically for nearly two decades to diagnose and stage liver fibrosis and cirrhosis, it has recently been appreciated for its ability to differentiate between more subtle forms of liver dysfunction. In this review, we will discuss the principle of ultrasound shear wave elastography, its traditional utilization in grading liver cirrhosis, as well as its evolving role in identifying more subtle degrees of liver injury.

The Impact of Silent Liver Disease on Hospital Length of Stay Following Isolated Coronary Artery Bypass Grafting Surgery.

Risk assessment models for cardiac surgery do not distinguish between degrees of liver dysfunction. We have previously shown that preoperative liver stiffness is associated with hospital length of stay following cardiac surgery. The authors hypothesized that a liver stiffness measurement (LSM) ≥ 9.

Sex-dependent phosphorylation of Argonaute 2 reduces the mitochondrial translocation of miR-181c and induces cardioprotection in females.

Obesity-induced cardiac dysfunction is growing at an alarming rate, showing a dramatic increase in global prevalence. Mitochondrial translocation of miR-181c in cardiomyocytes results in excessive reactive oxygen species (ROS) production during obesity. ROS causes Sp1, a transcription factor for MICU1, to be degraded via post-translational modification.

A case series evaluating the effect of esmolol therapy to treat hypoxemia in COVID-19 patients on VV-ECMO.

When COVID-19 ARDS abolishes pulmonary function, VV-ECMO can provide gas exchange. If oxygenation remains insufficient despite maximal VV-ECMO support, the addition of esmolol has been proposed. Conflict exists, however, as to the oxygenation level which should trigger beta-blocker initiation.

Reversing Neuromuscular Blockade without Nerve Stimulator Guidance in a Postsurgical ICU-An Observational Study.

We aimed to determine if not using residual neuromuscular blockade (RNB) analysis to guide neuromuscular blockade reversal administration in the postsurgical ICU resulted in consequences related to residual weakness. This single-center, prospective study evaluated 104 patients arriving in a postcardiac surgical ICU. After demonstrating spontaneous movement and T > 35.

A Mouse Model of Orotracheal Intubation and Ventilated Lung Ischemia Reperfusion Surgery.

Ischemia reperfusion (IR) injury frequently results from processes that involve a transient period of interrupted blood flow. In the lung, isolated IR permits the experimental study of this specific process with continued alveolar ventilation, thereby avoiding the compounding injurious processes of hypoxia and atelectasis. In the clinical context, lung ischemia reperfusion injury (also known as lung IRI or LIRI) is caused by numerous processes, including but not limited to pulmonary embolism, resuscitated hemorrhagic trauma, and lung transplantation.

Preoperative Liver Stiffness is Associated With Hospital Length of Stay After Cardiac Surgery.

Objectives: Risk assessment models for cardiac surgery do not account for the degrees of liver dysfunction. Ultrasound shear-wave elastography measures liver stiffness (LSM), a quantitative measurement related to fibrosis, congestion, and inflammation. The authors hypothesized that preoperative liver stiffness would be associated with hospital length of stay after cardiac surgery.

Selected Transesophageal Echocardiographic Parameters of Left Ventricular Diastolic Function Predict Length of Stay Following Coronary Artery Bypass Graft-A Prospective Observational Study.

(1) Importance: Abnormal left ventricular (LV) diastolic function, with or without a diagnosis of heart failure, is a common finding that can be easily diagnosed by intra-operative transesophageal echocardiography (TEE). The association of diastolic function with duration of hospital stay after coronary artery bypass (CAB) is unknown. (2) Objective: To determine if selected TEE parameters of diastolic dysfunction are associated with length of hospital stay after coronary artery bypass surgery (CAB).

Mixing commonly used crystalloid solutions with red blood cells in five common additives does not negatively impact hemolysis, aggregometry, or deformability.

Background: Literature is beginning to challenge the belief that it is unsafe to coinfuse red blood cells (RBCs) with solutions other than isotonic saline. We recently showed that additive-free RBCs tolerated coincubation with Plasma-Lyte or catecholamines dissolved in normal saline (NS), though 5% dextrose in water (D5W) promoted hemolysis. Herein, we evaluate the effect of coincubating crystalloids on additive-preserved RBC hemolysis, aggregation, and membrane deformability.

Diazoxide preserves myocardial function in a swine model of hypothermic cardioplegic arrest and prolonged global ischemia.

Objective: Adenosine triphosphate potassium sensitive channels provide endogenous myocardial protection via coupling of cell membrane potential to myocardial metabolism. Adenosine triphosphate potassium sensitive channel openers, such as diazoxide, mimic ischemic preconditioning, prevent cardiomyocyte swelling, preserve myocyte contractility after stress, and provide diastolic protection. We hypothesize that diazoxide combined with hyperkalemic cardioplegia provides superior myocardial protection compared with cardioplegia alone during prolonged global ischemia in a large animal model.

Incomplete Cushing's reflex in extracorporeal membrane oxygenation.

We report a case of intracranial hypertension presenting with bradycardia as the only component of Cushing's triad in a patient on extracorporeal membrane oxygenation. A 41-year-old woman with recurrent driveline infections of HeartMate-II had sternotomy and debridement that was complicated by right ventricular failure requiring veno-arterial extracorporeal membrane oxygenation. Patient was comatose and acute onset of bradycardia occurred without any change in blood pressure or respiration.

Effect of incubation with crystalloid solutions or medications on packed red blood cells.

Background: American Association of Blood Banks (AABB) guidelines suggest that packed red blood cells (PRBCs) be administered through a dedicated intravenous (IV) catheter. Literature supporting this broad-scope declaration are scarce. Obtaining additional IV access is painful, costly, and an infectious risk.

Chimerism, Transplant Tolerance, and Beyond.

The present review discusses current developments in tolerance induction for solid organ transplantation with a particular emphasis on chimerism-based approaches. It explains the basic mechanisms of chimerism-based tolerance and provides an update on ongoing clinical tolerance trials. The concept of "delayed tolerance" is presented, and ongoing preclinical studies in the nonhuman primate setting-including current limitations and hurdles regarding this approach-are illustrated.

CD36 mediates H2O2-induced calcium influx in lung microvascular endothelial cells.

Elevated levels of reactive oxygen species and intracellular Ca play a key role in endothelial barrier dysfunction in acute lung injury. We previously showed that HO-induced increases in intracellular calcium concentrations ([Ca]) in lung microvascular endothelial cells (LMVECs) involve the membrane Ca channel, transient receptor potential vanilloid-4 (TRPV4) and that inhibiting this channel attenuated HO-induced barrier disruption in vitro. We also showed that phosphorylation of TRPV4 by the Src family kinase, Fyn, contributes to HO-induced Ca influx in LMVEC.

Induction of Major Histocompatibility Complex-mismatched Mouse Lung Allograft Acceptance With Combined Donor Bone Marrow: Lung Transplant Using a 12-Hour Nonmyeloablative Conditioning Regimen.

Background: Despite broad and intense conventional immunosuppression, long-term survival after lung transplantation lags behind that for other solid organ transplants, primarily because of allograft rejection. Therefore, new strategies to promote lung allograft acceptance are urgently needed. The purpose of the present study was to induce allograft tolerance with a protocol compatible with deceased donor organ utilization.

CD8(+)IL-17(+) T Cells Mediate Neutrophilic Airway Obliteration in T-bet-Deficient Mouse Lung Allograft Recipients.

Acute cellular rejection is a known risk factor for the development of obliterative bronchiolitis, which limits the long-term survival of lung transplant recipients. However, the T cell effector mechanisms in both of these processes remain incompletely understood. Using the mouse orthotopic lung transplant model, we investigated whether C57BL/6 T-bet(-/-) recipients of major histocompatibility complex (MHC)-mismatched BALB/c lung grafts develop rejection pathology and allospecific cytokine responses that differ from wild-type mice.

Alveolar macrophages and Toll-like receptor 4 mediate ventilated lung ischemia reperfusion injury in mice.

Background: Ischemia-reperfusion (I-R) injury is a sterile inflammatory process that is commonly associated with diverse clinical situations such as hemorrhage followed by resuscitation, transient embolic events, and organ transplantation. I-R injury can induce lung dysfunction whether the I-R occurs in the lung or in a remote organ. Recently, evidence has emerged that receptors and pathways of the innate immune system are involved in recognizing sterile inflammation and overlap considerably with those involved in the recognition of and response to pathogens.

Interleukin-6 mediates pulmonary vascular permeability in a two-hit model of ventilator-associated lung injury.

To test the hypothesis that interleukin-6 (IL-6) contributes to the development of ventilator-associated lung injury (VALI), IL-6-deficient (IL6(-/-)) and wild-type control (WT) mice received intratracheal hydrochloric acid followed by randomization to mechanical ventilation (MV + IT HCl) or spontaneous ventilation (IT HCl). After 4 hours, injury was assessed by estimation of lung lavage protein concentration and total and differential cell counts, wet/dry lung weight ratio, pulmonary cell death, histologic inflammation score (LIS), and parenchymal myeloperoxidase (MPO) concentration. Vascular endothelial growth factor (VEGF) concentration was measured in lung lavage and homogenate, as IL-6 and stretch both regulate expression of this potent mediator of permeability.

Interactive effects of mechanical ventilation and kidney health on lung function in an in vivo mouse model.

We hypothesized that the influence of acute kidney injury (AKI) on the sensitivity of the lung to an injurious process varies with the severity of the injurious process. Thus, we thought that AKI would exacerbate lung injury from low degrees of lung trauma but attenuate lung injury from higher degrees of lung trauma. C57BL/6 mice underwent AKI (30-min kidney ischemia) or sham surgery, followed at 24 h by 4 h of spontaneous breathing (SB), mechanical ventilation with low tidal volume (7 ml/kg, LTV), or mechanical ventilation with high tidal volume (30 ml/kg, HTV).

The role of natriuretic peptide receptor-A signaling in unilateral lung ischemia-reperfusion injury in the intact mouse.

Ischemia-reperfusion (IR) causes human lung injury in association with the release of atrial and brain natriuretic peptides (ANP and BNP), but the role of ANP/BNP in IR lung injury is unknown. ANP and BNP bind to natriuretic peptide receptor-A (NPR-A) generating cGMP and to NPR-C, a clearance receptor that can decrease intracellular cAMP. To determine the role of NPR-A signaling in IR lung injury, we administered the NPR-A blocker anantin in an in vivo SWR mouse preparation of unilateral lung IR.

Strain-specific differences in sensitivity to ischemia-reperfusion lung injury in mice.

Ischemia-reperfusion (I/R) lung injury is characterized by increased pulmonary endothelial permeability and edema, but the genetic basis for this injury is unknown. We utilized an in vivo mouse preparation of unilateral lung I/R to evaluate the genetic determinants of I/R lung injury. An index of pulmonary vascular protein permeability was measured by the ratio of left-to-right lung Evans blue dye of eight inbred mouse strains after 30 min of left lung ischemia and 150 min of reperfusion.

Effect of NADPH oxidase inhibition on cardiopulmonary bypass-induced lung injury.

Cardiopulmonary bypass (CPB) causes acute lung injury. Reactive oxygen species (ROS) from NADPH oxidase may contribute to this injury. To determine the role of NADPH oxidase, we pretreated pigs with structurally dissimilar NADPH oxidase inhibitors.

Effect of bronchial artery blood flow on cardiopulmonary bypass-induced lung injury.

Cardiovascular surgery requiring cardiopulmonary bypass (CPB) is frequently complicated by postoperative lung injury. Bronchial artery (BA) blood flow has been hypothesized to attenuate this injury. The purpose of the present study was to determine the effect of BA blood flow on CPB-induced lung injury in anesthetized pigs.

Effect of ischemia and reperfusion without airway occlusion on vascular barrier function in the in vivo mouse lung.

Ischemia-reperfusion (I/R) lung injury causes increased vascular permeability and edema. We developed an in vivo murine model of I/R allowing measurement of pulmonary vascular barrier function without airway occlusion. The left pulmonary artery (PA) was occluded with an exteriorized, slipknotted suture in anesthetized C57BL/6J mice.