Anaesthesia and intensive care
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We have previously postulated that it is possible to accidentally insert an epidural needle or catheter into the substance of the dura during attempted epidural block, creating an intradural space. It appears that injection of local anaesthetic into an intradural space leads to an initially inadequate neuraxial block but further doses may produce an extensive life-threatening block. In the laboratory, 54 samples of human thoraco-lumbar dura were obtained from six cadavers and prepared for scanning electron microscopy. ⋯ Electron microscopy revealed the concentric laminae that compose the dura and the presence of artefactual spaces between some of these. It was possible to insert an epidural catheter into the substance of the dura in eight specimens, creating intradural spaces which remained following catheter removal. If this represents the clinical situation, it may help to explain previously reported cases of atypical neuraxial block and their associated radiological findings.
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Anaesth Intensive Care · Nov 2011
Evaluation of a humidified nasal high-flow oxygen system, using oxygraphy, capnography and measurement of upper airway pressures.
In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow, Fisher and Paykel Healthcare) by measuring delivered FiO, and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. ⋯ At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cm H20. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.
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Anaesth Intensive Care · Nov 2011
Evaluating sleep characteristics in intensive care unit and non-intensive care unit physicians.
Healthcare workers' cognitive performances and alertness are highly vulnerable to sleep loss and circadian rhythms. The purpose of this study was to investigate the changes in sleep characteristics of intensive care unit (ICU) and non-ICU physicians. Actigraphic sleep parameters, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Hamilton Depression Rating Scale were evaluated for ICU and non-ICU physicians on the day before shift-work and on three consecutive days after shift-work. ⋯ Total sleep time, total activity score and sleep efficiency scores prior to shift-work were significantly different from shift-work and the three consecutive-days after shift-work, in both groups. Working in the ICU does not have an impact on objective sleep characteristics of physicians in this study. Large cohort studies are required to determine long-term health concerns of shift-working physicians.
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Anaesth Intensive Care · Nov 2011
Surgical tension pneumothorax during laparoscopic repair of massive hiatus hernia: a different situation requiring different management.
During laparoscopic repair of massive hiatus hernia, surgical dissection can breach the parietal pleura allowing insufflating carbon dioxide to rapidly expand the pleural space, causing a tension pneumothorax. This extrapulmonary pneumothorax involves no damage to the lung parenchyma. Its rapid resolution is aided by the high solubility of carbon dioxide and it will not refill once the procedure is completed. ⋯ Cardiovascular compromise occurred in 91% of those (10/11). The aetiology, pathophysiology and management of this intraoperative capnothorax differ significantly from that of a pneumothorax secondary to lung trauma or occurring during other types of laparoscopy. Understanding the relevant pleural anatomy and pathophysiology of this condition allowed conservative management in all cases and avoided the need for chest drains, open surgery or abandonment of the procedure.
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Thrombotic microangiopathies are a rare group of disorders with features such as microangiopathic haemolytic anaemia, thrombocytopenia and renal failure. Thrombotic microangiopathy has been previously reported in association with envenomation from a number of snake species. ⋯ The presentations and recovery were similar to case presentations of other snakebite envenomation associated thrombotic microangiopathies. Normal ADAMTS13 activity suggests that plasmapharesis may not be beneficial, although this needs further investigation.