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Adequate Oxygenation (adequate + oxygenation)
Selected AbstractsPercutaneous transtracheal emergency ventilation with a self-made device in an animal modelPEDIATRIC ANESTHESIA, Issue 10 2007RAIK SCHAEFER Summary Background:, Special equipment for emergency percutaneous transtracheal ventilation is often not immediately available. We used a self-made device consisting of a three-way stopcock connected between a G-15 transtracheal airway catheter and an oxygen supply in a simulated 'cannot intubate, cannot ventilate' scenario and tested the hypothesis that the effectiveness of the device depends on the body weight of the experimental animals. Methods:, With approval of the local animal protection committee, two groups of six pigs each with a body weight of 21 ± 2 and 36 ± 6 kg, respectively, were tracheally intubated and mechanically ventilated after induction of anesthesia. Hemodynamic monitoring included cardiac output and arterial, central venous and pulmonary artery pressures. An emergency transtracheal airway catheter was inserted into the trachea and a situation of partial expiratory airway obstruction was created. Each animal was ventilated for 15 min via the transtracheal airway catheter with the self-made device (FiO2 1.0 at an oxygen flow of 15 l·min,1; respiratory rate of 60 min,1; I/E ratio approximately 1 : 1). Results:, Whereas satisfactory oxygenation was achieved in all animals, sufficient ventilation was obtained only in the lightweight animals. Conclusions:, Adequate oxygenation could be provided by jet-like transtracheal ventilation with a simple self-made device using easily available materials. Sufficient ventilation depends on the body weight of the animals. [source] Design of an Ultrasound Contrast Agent for Myocardial PerfusionECHOCARDIOGRAPHY, Issue 2000Michel Schneider Ph.D. Myocardial contrast echography (MCE) has been a major research objective in cardiovascular ultrasound for almost two decades. The design of a contrast agent fulfilling the needs of MCE requires taking into consideration a number of points: a basic decision has to be made whether a deposit agent or a free-flowing agent would be more appropriate and whether an agent active at low/medium mechanical index (MI) is preferable to an agent active only at high MI; only a small percentage of the cardiac output enters the coronary microcirculation, which means that highly sensitive bubble detection methods, such as harmonic imaging or pulse inversion, are needed; the low velocity of blood in the microcirculation that leads to extensive bubble destruction during imaging means that intermittent imaging and/or an agent active at low MI is (are) required; the duration of the contrast effect must be sufficient to allow a complete examination and is affected by the rate of contrast administration; the performance of the contrast agent should not be equipment-dependent. The ultimate goal in MCE is to be able to quantify blood flow in the various segments to determine if adequate oxygenation is achieved. Ultrasound-mediated bubble destruction followed by the measurement of bubble replenishment kinetics opens new perspectives for quantification. SonoVue is a free-flowing ultrasound contrast agent made of sulphur hexafluoride microbubbles stabilized by a highly elastic phospholipid monolayer. SonoVue is able to produce myocardial opacification at a wide range of acoustic pressures and in particular at Mis as low as 0.1. Its performance is not equipment-dependent. Good results for myocardial opacification have been observed in all animal species tested (dogs, minipigs, rabbits), using continuous as well as intermittent imaging. Trials are in progress to demonstrate the clinical utility of SonoVue for rest and stress perfusion studies, in particular for the diagnosis of CAD, the detection of myocardial infarction, the assessment of the success of interventions and myocardial viability, and the detection of hibernating myocardium. [source] The Role of the Kidneys in HypertensionJOURNAL OF CLINICAL HYPERTENSION, Issue 9 2005L. Gabriel Navar PhD The devastating long-term consequences of high blood pressure include stroke, heart disease, atherosclerosis, renal disease, and other end-organ damage. From a physiologic perspective, it is not apparent why the propensity for hypertension is so widespread in the general population. Clearly, an adequate arterial pressure is essential for perfusion of the tissues to provide adequate oxygenation and nutrition to the brain and other critical organs. Although the various microcirculatory beds have the capability to adjust vascular resistance to autoregulate blood flow, systemic arterial pressure is usually maintained at levels greater than required for requisite tissue perfusion. The myriad of neurohumoral mechanisms designed to protect against decreases in systemic arterial pressure provide a reserve capacity for increased perfusion when there are increased tissue demands. The unfortunate consequence of having these powerful physiologic control mechanisms is that they may be inappropriately activated in certain circumstances or by genetically determined traits, leading to hypertension and cardiovascular injury. Evidence continues to accumulate indicating that the kidney not only is victim to hypertension-related injury, but also contributes as a villain to the hypertensinogenic process. [source] Overnight Hospital Stay Is Not Always Necessary after Uvulopalatopharyngoplasty,THE LARYNGOSCOPE, Issue 1 2005FACS, Jeffrey H. Spiegel MD Abstract Objectives: To determine whether patients with obstructive sleep apnea who undergo uvulopalatopharyngoplasty (UPPP) have a significant incidence of postoperative complications that would justify overnight postoperative observation in the hospital. Study Design: Part 1: review of published medical literature to determine incidence of postoperative complications. Part 2: retrospective review of 117 patients undergoing UPPP with or without additional procedures. Methods: A literature search for existing studies describing the postoperative complications after UPPP for obstructive sleep apnea was conducted. After this, the records of 117 patients who had undergone UPPP at a university-based medical center during a 5-year span were reviewed. Results: Respiratory events occur in 2% to 11% of cases. These include airway obstruction (e.g., laryngospasm), postobstructive pulmonary edema (POPE), and desaturation. Airway obstruction occurred in the immediate postoperative setting. POPE was rare and usually occurred within minutes after the conclusion of the surgical procedure. Desaturation could occur at any time, but the severity was usually equivalent to that found on preoperative sleep study. Hemorrhage occurred in 2% to 14% of cases and had a biphasic incidence, occurring either immediately postoperatively or several days after surgery. Depending on definition, hypertension was observed in between 2% and 70% of patients postoperatively. This was most commonly diagnosed and treated in the immediate postoperative setting. In most reports, arrhythmia and angina occurred in less than 1% of cases. Conclusions: The majority of complications after UPPP with or without additional procedures occur within 1 to 2 hours after surgery. Postoperative oxygen desaturation is usually no worse than that that was observed on preoperative polysomnography findings. A 2 to 3 hour observation period may be suitable for patients after UPPP; if a patient experiences no complications and is maintaining adequate oxygenation and analgesia, same-day discharge from recovery room may be considered. [source] The Aachen Miniaturized Heart-Lung Machine,First Results in a Small Animal ModelARTIFICIAL ORGANS, Issue 11 2009Heike Schnoering Abstract Congenital heart surgery most often incorporates extracorporeal circulation. Due to foreign surface contact and the administration of foreign blood in many children, inflammatory response and hemolysis are important matters of debate. This is particularly an issue in premature and low birth-weight newborns. Taking these considerations into account, the Aachen miniaturized heart-lung machine (MiniHLM) with a total static priming volume of 102 mL (including tubing) was developed and tested in a small animal model. Fourteen female Chinchilla Bastard rabbits were operated on using two different kinds of circuits. In eight animals, a conventional HLM with Dideco Kids oxygenator and Stöckert roller pump (Sorin group, Milan, Italy) was used, and the Aachen MiniHLM was employed in six animals. Outcome parameters were hemolysis and blood gas analysis including lactate. The rabbits were anesthetized, and a standard median sternotomy was performed. The ascending aorta and the right atrium were cannulated. After initiating cardiopulmonary bypass, the aorta was cross-clamped, and cardiac arrest was induced by blood cardioplegia. Blood samples for hemolysis and blood gas analysis were drawn before, during, and after cardiopulmonary bypass. After 1 h aortic clamp time, all animals were weaned from cardiopulmonary bypass. Blood gas analysis revealed adequate oxygenation and perfusion during cardiopulmonary bypass, irrespective of the employed perfusion system. The use of the Aachen MiniHLM resulted in a statistically significant reduced decrease in fibrinogen during cardiopulmonary bypass. A trend revealing a reduced increase in free hemoglobin during bypass in the MiniHLM group could also be observed. This newly developed Aachen MiniHLM with low priming volume, reduced hemolysis, and excellent gas transfer (O2 and CO2) may reduce circuit-induced complications during heart surgery in neonates. [source] Gas embolism: pathophysiology and treatmentCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2003Robert A. van Hulst Summary Based on a literature search, an overview is presented of the pathophysiology of venous and arterial gas embolism in the experimental and clinical environment, as well as the relevance and aims of diagnostics and treatment of gas embolism. The review starts with a few historical observations and then addresses venous air embolism by discussing pulmonary vascular filtration, entrapment, and the clinical occurrence of venous air emboli. The section on arterial gas embolism deals with the main mechanisms involved, coronary and cerebral air embolism (CAE), and the effects of bubbles on the blood,brain barrier. The diagnosis of CAE uses various techniques including ultrasound, perioperative monitoring, computed tomography, brain magnetic resonance imaging and other modalities. The section on therapy starts by addressing the primary treatment goals and the roles of adequate oxygenation and ventilation. Then the rationale for hyperbaric oxygen as a therapy for CAE based on its physiological mode of action is discussed, as well as some aspects of adjuvant drug therapy. A few animal studies are presented, which emphasize the importance of the timing of therapy, and the outcome of patients with air embolism (including clinical patients, divers and submariners) is described. [source] | ||||||||||