British journal of anaesthesia
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Randomized Controlled Trial Multicenter Study
Population pharmacokinetics of tranexamic acid in adults undergoing cardiac surgery with cardiopulmonary bypass.
Interest in antifibrinolytic tranexamic acid (TA) has grown since the widespread removal of aprotinin, but its dosing during cardiac surgery is still debated. The objectives of this study were to investigate the population pharmacokinetics (PK) of TA given with either low- or high-dose continuous infusion schemes in adult cardiac surgery patients during cardiopulmonary bypass (CPB). ⋯ The PK of TA was satisfactorily described by an open two-compartmental model, which was used to propose a dosing scheme suitable for obtaining and maintaining the desired plasma concentration in a stable and narrow range in cardiac surgery patients.
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Comparative Study
Comparison of haemoglobin measurement methods in the operating theatre.
Various methods of haemoglobin (Hb) measurement are available to guide transfusion including several methods that allow for measurement at the bedside. This study directly compared their absolute and trend accuracy compared with values from the central lab (reference method). ⋯ Bedside Hb measurement methods differ in their agreement to a laboratory haematology analyser but none would have led to transfusion errors. Trial Registry Number RCB 2009-AO1144-53.
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Respiratory rate is an important measurement in patient care, but accurate measurement is often difficult. We have developed a simple non-invasive device to measure respiratory movements in clinical circumstances, with minimal interference with the patient. We investigated respiratory patterns in patients receiving postoperative morphine analgesia to assess the capacity of the device to detect abnormalities. ⋯ In undisturbed subjects receiving patient-controlled morphine analgesia after surgery, abnormal breathing patterns are extremely common. Cyclical airway obstruction is frequent and associated with a typical pattern of changes in chest wall movement.
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Bioreactance estimates cardiac output in a non-invasive way. We evaluated the ability of a bioreactance device (NICOM®) to estimate cardiac index (CI) and to track relative changes induced by volume expansion. ⋯ The NICOM® device cannot accurately estimate the cardiac output in critically ill patients. Moreover, it could not predict fluid responsiveness through the PLR test.
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Observational Study
Neuro-ventilatory efficiency during weaning from mechanical ventilation using neurally adjusted ventilatory assist.
Neuro-ventilatory efficiency (NVE), defined as the tidal volume to electrical diaphragm-activity ratio (VT/EAdi) at the beginning and end of the weaning process after acute hypoxaemic respiratory failure, may provide valuable information about patient recovery. ⋯ These results suggest that in patients after respiratory failure and prolonged mechanical ventilation, changes in VT and NVE, between SBTs are indicative of patient recovery. Larger clinical trials are needed to clarify whether changes in NVE reliably predict weaning in patients ventilated with NAVA.