Anaesthesia and intensive care
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Traditional mechanical ventilation used tidal volumes (Vt) of between 10 to 15 ml/kg of body weight in order to achieve normal values of pH and partial pressure of carbon dioxide (PaCO2). Many clinicians today however, adopt lower volumes as a conservative 'safe' ventilation strategy in most mechanically ventilated patients. The method by which this is done varies between facilities, but anecdotally doctors use Vt of 6 to 8 ml/kg, and they commonly estimate these volumes at the bedside. ⋯ Although volumes between 6 to 8 ml/kg were recorded in 33 (60%) observations, more detailed exploration of the individual's clinical circumstances reflects that the actual dialled volumes were correct in all but two patients. Intensive care unit mortality was 13% (n=2) in those patients receiving higher than anticipated Vts (n=15). This study has demonstrated that while we achieve a protective ventilation strategy by adopting lower Vts in most mechanically ventilated patients, we should be constantly monitoring exactly what volume is being achieved, not just what is dialled up to be delivered.
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Anaesth Intensive Care · Jul 2012
ReviewThe interpretation of perioperative lactate abnormalities in patients undergoing cardiac surgery.
Hyperlactataemia and lactic acidosis are commonly encountered during and after cardiac surgery. Perioperative lactate production increases in the myocardium, skeletal muscle, lungs and in the splanchnic circulation during cardiopulmonary bypass. Hyperlactataemia has a bimodal distribution in the perioperative period. ⋯ Risk factors for late-onset hyperlactataemia include hyperglycaemia, long cardiopulmonary bypass time and elevated endogenous catecholamines. Although patients with this complication may have a longer duration of ventilation and intensive care unit length of stay than those with normolactataemia, an association with increased mortality has not been demonstrated. The discovery of late-onset hyperlactataemia should not delay the postoperative progress of an otherwise stable patient following cardiac surgery.
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We endeavored to thoroughly review Greek mythology and collect tales dealing with anaesthesia and myochalasis (paralysis). Among the evaluated sources were the poems of Hesiod, the epics of Homer, the tragedies of the great Athenian poets (namely Aeschylus, Sophocles and Euripides) as well as the contributions of several Latin writers, including Ovid. We found several examples of achieving hypnosis, analgesia and amnesia through the administration of drugs (inhaled or not) and music. ⋯ We noted that providing sleep was considered a divine privilege, although several mortals (mainly women) exhibited such powers as well. The concepts of sleep and death were closely associated in ancient classical thought. This review may stimulate anaesthetists' fantasy and may help them realise the nobility of their medical specialty.
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Anaesth Intensive Care · Jul 2012
Observations on the assessment and optimal use of videolaryngoscopes.
Due to the large number of videolaryngoscopes now available, it might be difficult for novice users to assess the various devices or use them optimally. We have collated the experiences of several airway management experts to assist in the assessment and optimal use of seven commonly used videolaryngoscopes. While all videolaryngoscopes have unique features, they can be broadly divided into those inserted via a midline approach over the tongue and those inserted laterally along the floor of the mouth. ⋯ Videolaryngoscopes that use the midline approach may have an in-built airway conduit for the tracheal tube or may require a 'J-shaped' stylet in the tracheal tube to negotiate the upper airway. This may cause difficulty when the tracheal tube is inserted through the glottis and the tip abuts the anterior wall of the subglottic space. Knowledge of the mechanism used by videolaryngoscopes to achieve laryngoscopy is essential for safe and successful tracheal intubation when using these devices.