View clinical trials related to Shock.
Filter by:Shock and respiratory failure are common reasons for admission to the intensive care unit (ICU) at our institution. The various causes of acute shock and respiratory failure are traditionally assessed with the use of history, physical examination, chest x-ray, EKG and laboratory studies. Unfortunately, much of this clinical information is either insensitive or non-specific. 1 Critical care ultrasound (CCUS) is a rapid and non-invasive tool, which has been shown to be useful in the intensive care unit to assist in the diagnosis and management of patients in shock or respiratory failure.2 The investigators hypothesize that the trained fellow's interpretation of critical care ultrasound images will be accurate when compared to experts and that ultrasounds will change diagnosis and management of the patient in shock and respiratory failure.
In prehospital settings, hypovolemic shock diagnosis is based on Advanced Trauma Life Support (ATLS) shock classification. The most often used clinical signs are heart rate (HR), arterial blood pressure (BP), respiratory rate, neurologic status, diuresis, skin colour and temperature. However, some of these signs, such as hypotension and tachycardia, lack specificity and sensitivity and do not occur early enough. Even with an early preload reduction, blood pressure can remain constant due to compensatory mechanisms, such as vasoconstriction and positive chronotropism. Tachycardia occurs earlier, but has poor specificity and sensitivity. A retrospective analysis of 25,287 trauma patients showed that among 489 patients presenting with systolic BP < 90 mmHg, only 65% had tachycardia (HR > 90 bpm), while 39% of patients with systolic BP > 120 mmHg were tachycardic, probably resulting from other stimuli influencing heart rate, such as pain, fear, circulating hormones and endogenous enkephalins. Therefore, it could be very useful to have an index that identifies initial volume variation, when physiological regulatory mechanisms are still effectively maintaining normal BP. Pulse transit time (PTT) is the sum of pre-ejection period (PEP; the time interval between the onset of ventricular depolarization and ventricular ejection) and vascular transit time (VTT; the time it takes for the pulse wave to travel from the aortic valve to peripheral arteries). PEP and VTT variations depend on preload variation, and PTT increases with PEP, showing a linear correlation (R2 = 0.96). Chan et al. subjected 11 healthy volunteers to the head-up tilt test, and demonstrated that PEP increased and VTT decreased for increasing tilt angles from 0° to 80°, corresponding to light-moderate bleeding. They also observed early sympathetic activation, expressed by decreases of both RR interval (RR) and VTT, dampening the PTT increase, since PTT is influenced by both continuous PEP increase and progressive VTT decrease occurring during hypovolaemia. Here the investigators describe a new index, called indexed Heart to Arm Time (iHAT). iHAT is the mPTT/RR ratio, where mPTT is a modified PTT, measured from the onset of ventricular depolarization (the 'R' wave of the ECG trace) to the systolic peak of the photoplethysmographic pulse oxymetry (PPG) waveform. mPTT is indexed to RR interval on ECG to counteract sympathetic activation that would dampen PEP increase and enhance VTT reduction, by means of positive inotropism and peripheral vasoconstriction, respectively. iHAT therefore increases during haemorrhage because of preload reduction and the consequent PEP increase and RR interval decrease. iHAT is expressed as the time percentage of the interbeat interval (RR) it takes to the PPG waveform to travel to peripheral arteries. In this study iHAT has been calculated as the average of beat-to-beat mPTT/RR ratios over 30 heart beats (corresponding to at least 2 breathing cycles) in order to minimize the effect of spontaneous breathing on preload, and thus on PEP and PTT. In the present study, the investigators aimed to evaluate iHAT in a simulating model of hypovolaemia by using a Lower Body Negative Pressure (LBNP) chamber. LBNP chamber simulates haemorrhage by applying negative pressure to the lower limbs, thus giving an accurate model of hypovolemia. The LBNP chamber has been used for many years for research purposes, and in 2001 Convertino suggested it is a useful device to test severe haemorrhage-related hemodynamic responses. In fact, the induced volemic sequestration is an efficient technique to study physiological behaviours in humans. The primary endpoint was to evaluate the use of the iHAT as a predictor of hypovolaemia. The secondary endpoint was to compare the specificity and sensitivity of the iHAT index compared to commonly used indexes (BP, HR). Furthermore, the investigators aimed to assess feasibility of Transthoracic echocardiography (TTE) evaluation of Cardiac Output (CO) in a haemorrhagic model and to evaluate CO changes with respect to measured hemodynamic variables. TTE evaluation of CO is non invasive and comparable to thermodilution, and of possible use in an emergency setting.
The Shock Tool study is designed to improve the clinical evaluation for differentiating shock in the emergency department. The goal of this study is to evaluate and improve the accuracy of physicians differentiating causes of shock.
The relationship between shock, ischemia and reperfusion (I/R) injury, hemodynamic instability, systemic inflammatory response syndrome and multiorgan failure has been extensively investigated, but there is no consensus on the trigger mechanisms of tissue injury at the molecular level. Current therapies are targeted to reduce symptoms of shock and multiorgan damage but they are unable to act at the "beginning of the cascade", because of the lack of a model explaining the molecular basis of shock induced tissue injury and ensuing organ damage. The present observational study is aimed at identifying the molecular triggers of acute heart failure (HF) induced by shock and to identify inflammatory mediators and markers that are activated in shock, with a particular emphasis on the role of uncontrolled proteolytic activity.
Sepsis is a clinical syndrome which infection trigger systemic inflammatory response. Uncontrolled inflammatory process leads to multiple organ dysfunction and cause early mortality in severe sepsis. Unfractionated heparin is an anticoagulant that widely used either for DVT prophylaxis or treatment of disseminated intravascular coagulation. Heparin also have an anti-inflammatory effect through downregulates nuclear factor kappa B and tumor necrosis factor alpha. Aim of this study is to determine effects of low dose unfractionated heparin treatment on inflammation in severe sepsis patient.
The main objective of this study is to evaluate in a population of patients with septic shock receiving 500 ml crystalloid over 10 minutes, the proportion of patients classified as "responders" to the fluid challenge (increase of at least 15% of ITV in aortic) at the end of vascular filling (T10) and becoming "non-responders" 20 minutes after the end of the fluid challenge (T30) and whether this proportion is greater than 10 points.
The purpose of this study is to find out whether stress doses of hydrocortisone attenuate coagulation dysfunction in patients with septic shock. And discuss the probable mechanism by which little doses of hydrocortisone influence coagulation system in sepsis.
Haemorrhage following major trauma is an important preventable cause of death. Those patients who survive may have a prolonged period of debility caused by failure of key body organs. We suspect that an important contributor to this organ failure may be dysfunction in the network of small blood vessels that supply the bodies organs with oxygen and nutrients. Our study will examine the link between the microcirculation and organ failure in patients who have suffered significant bleeding after traumatic injury. We will also explore the relationship between resuscitation of the global circulation (blood pressure, cardiac output etc.)an area that is monitored in clinical practice with the state of the microcirculation, which by contrast is not monitored. Patients with severe traumatic injury commonly have problems with blood clotting. Some researchers have suggested that microcirculatory failure may be an important contributor to this problem and we will explore this in more detail. Finally, we will attempt to examine some of the mechanisms by which the microcirculation may be disrupted by trauma and subsequent bleeding. These may include inappropriate activation of white blood cells, inadequate function of oxygen carrying red blood cells and changes to the cells lining the small blood vessels. We will use a non invasive method to assess the microcirculation termed Side Stream Dark Field microscopy. This involves recorded a video image of the movement of blood within the small blood vessels under a patients tongue. In addition we will use ultrasound to assess the flow of blood from the heart. Small samples of blood will be taken to assess blood clotting and to look at possible mechanisms of microcirculatory dysfunction. We aim to study ten patients in the first instance. The study will be carried out within the intensive care units at Kings College Hospital.
The investigators hypothesize that there is a strong correlation between OSA and TBM/HDAC. Our hypothesis is based on the similarities in mechanism (airway collapse), symptoms (daytime and nocturnal dyspnea) predisposing conditions (obesity and neuromuscular abnormalities of the chest wall and the diaphragm), and effect of interventions (CPAP and BIPAP) in these diseases.
Assess the effect of fluids and norepinephrine for mean arterial pressure titration to patients' usual level on the microcirculation of initial resuscitated hypertensive septic shock patients.