Endogenous protease nexin-1 protects against cerebral ischemia.

The serine protease thrombin plays a role in signalling ischemic neuronal death in the brain. Paradoxically, endogenous neuroprotective mechanisms can be triggered by preconditioning with thrombin (thrombin preconditioning, TPC), leading to tolerance to cerebral ischemia. Here we studied the role of thrombin's endogenous potent inhibitor, protease nexin-1 (PN-1), in ischemia and in tolerance to cerebral ischemia induced by TPC. Cerebral ischemia was modelled in vitro in organotypic hippocampal slice cultures from rats or genetically engineered mice lacking PN-1 or with the reporter gene lacZ knocked into the PN-1 locus PN-1HAPN-1-lacZ/HAPN-1-lacZ (PN-1 KI) exposed to oxygen and glucose deprivation (OGD). We observed increased thrombin enzyme activity in culture homogenates 24 h after OGD. Lack of PN-1 increased neuronal death in the CA1, suggesting that endogenous PN-1 inhibits thrombin-induced neuronal damage after ischemia. OGD enhanced ß-galactosidase activity, reflecting PN-1 expression, at one and 24 h, most strikingly in the stratum radiatum, a glial cell layer adjacent to the CA1 layer of ischemia sensitive neurons. TPC, 24 h before OGD, additionally increased PN-1 expression 1 h after OGD, compared to OGD alone. TPC failed to induce tolerance in cultures from PN-1(-/-) mice confirming PN-1 as an important TPC target. PN-1 upregulation after TPC was blocked by the c-Jun N-terminal kinase (JNK) inhibitor, L-JNKI1, known to block TPC. This work suggests that PN-1 is an endogenous neuroprotectant in cerebral ischemia and a potential target for neuroprotection.

The Evolution of Cardiovascular Ultrasound: A Review of Cardiac Point-of-Care Ultrasound (POCUS) Across Specialties.

The use of cardiac point-of-care ultrasound (POCUS) is now widespread in clinics, emergency departments, and all areas of the hospital. Users include medical trainees, advanced practice practitioners, and attending physicians in many specialties and sub-specialties. Opportunities to learn cardiac POCUS and requirements for training vary across specialties, as does the scope of the cardiac POCUS examination. In this review, we describe both a brief history of how cardiac POCUS emerged from echocardiography and the state of the art across a variety of medical fields.

Early versus late tracheostomy in cardiovascular intensive care patients.

BACKGROUND: Benefits of tracheostomy have been well established. Most of the literature, refers these benefits to general intensive care population, excluding cardiac surgery or including only small number of these patients. On the other hand, there is no clear definition describing the proper time to perform the procedure and defining what are potential benefits of early compared to late tracheostomy. This retrospective cohort aims to assess the potential benefits of early tracheostomy on post-operative outcomes, length of stay and post-tracheostomy complications within cardiac surgical population. METHODS: After obtaining REB approval, we conducted a retrospective chart review in a single, tertiary care institution, identifying patients who underwent tracheostomy after cardiac surgery from 1999 to 2006. Time-to-tracheostomy was defined as "early" if < 7 days or "late" if ≥ 7 days post-cardiac surgery). RESULTS: 14,101 patients underwent cardiac surgery over the 7-year study period; from those, 147 (1.36%) received tracheostomy. 32 (22%) patients underwent early tracheostomy and 115 (78%) late tracheostomy. Incidence of atrial fibrillation (31.2% vs 61.7%; P = 0.003), kidney dysfunction (6.3% vs 27.2%; P=0.015) and kidney failure 18.8% vs 43.5%; P = 0.013) were lower in the early tracheostomy group. There were no differences on post tracheostomy infection or presence of acute respiratory distress syndrome. Both the ICU and hospital length of stay were significantly shorter in early tracheostomy group, 21.5 (ET) vs 36.9 (LT) days and 37.5 (ET) vs 57.6 (LT) days respectively. There were no differences in mortality between groups. CONCLUSIONS: There are significant benefits in reduction of postoperative morbidities with overall shorter ICU and hospital stay. These benefits may promote faster patient rehabilitation with reduced healthcare costs.

Ultrasonido de la cabeza a los pies: opinión actual sobre su utilidad en inestabilidad hemodinámica, hipoxemia, oligoanuria y en el paciente con estado neurológico alterado / Head to toe ultrasound: Current opinion on its role in hemodynamic instability, hypoxemia, oligoanuria and the patient with altered neurological status

Abstract Introduction: Bedside ultrasound is now more commonly used in anesthesiology and critical care. There are numerous applications beyond its role in regional anesthesia and vascular access. Objective: To describe how bedside ultrasound can be integrated to current clinical management is dealingwith hemodynamicallyunstable, hypoxemic, oligoanuric patient and in the patient with altered neurological status. Material and methods: Essay article describing a synthesis of the current literature, expert opinion, currentpracticeand recentclinicaltrials in the developmentofproposed algorithm dealing with the use of bedside ultrasound in the management hemodynamic instability and hypoxemia. Results: Three algorithms currently used in the hemodynamically unstable and the hypox-emic patient and the patient are described. In addition, a simple bedside ultrasound approach to oligoanuria and altered neurological status is proposed. Conclusion: Further studies incorporating head-to-toe bedside ultrasound by trained clinicians will need to be validated but are likely to demonstrate the significant advantages of incorporating bedside ultrasound in the practice of anesthesiology and critical care.

Resumen Introducción: El ultrasonido realizado al lado de la cama del paciente se utiliza cada vez con más frecuencia en anestesiología y cuidado crítico. Son muchas sus aplicaciones aparte de la anestesia regional y el acceso vascular. Objetivo: Describir la forma de integrar el ultrasonido al lado de la cama del paciente en el actual manejo clínico del paciente hemodinámicamente inestable, hipoxémico y oligoanúrico, y del paciente con estado neurológico alterado. Materiales y métodos: Ensayo que describe una síntesis de la literatura actual, las opiniones de expertos, la práctica corriente y los experimentos clínicos recientes para el desarrollo de la propuesta de un algoritmo relativo al uso del ultrasonido al lado de la cama del paciente en el manejo de la inestabilidad hemodinámica y la hipoxemia. Resultados: Se describen 3 algoritmos utilizados actualmente en el paciente hemodinámicamente inestable e hipoxémico. Adicionalmente se propone un enfoque simple de ultrasonido a la cabecera del paciente para la oligoanuria y el estado neurológico alterado. Conclusión: Será necesario validar estudios ulteriores que incorporen la realización de ultrasonido de la cabeza a los pies por parte de clínicos entrenados, pero es probable que demuestren las ventajas importantes de incorporar el ultrasonido a la cabecera del paciente en la práctica de la anestesiología y el cuidado crítico.