Anaesthesia
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Fixed performance venturi devices should provide a predetermined oxygen concentration at an outflow which exceeds an adult's peak resting inspiratory flow rate (approximately 30 l.min(-1)). Campbell's original description mentioned the sensitivity of the venturi device to downstream resistance but gave no further details. This study examined outflow and oxygen concentration from the five standard venturi devices (24-60% O(2)) when downstream pressure increased. ⋯ The outflow at zero downstream pressure for the 24-40% O(2) venturi devices ranged from 40 to 50 l.min(-1) but only 2-3 mmH(2)O was needed to halve this flow and increase oxygen concentration. The 60% O(2) venturi delivered a maximum of only 30 l.min(-1) at zero downstream pressure and flow was reduced further by increasing this pressure. An increase in downstream pressure of only a few mmH(2)O increased oxygen concentration and decreased outflow of all the venturi devices tested, in most to less than normal peak tidal flow in adults.
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Continuous flow positive pressure devices bridge the gap between mechanical and unsupported ventilation in patients recovering from critical illness. At this point, patients are often fully awake, yet the inflated tracheostomy cuff prevents them from speaking or swallowing. The aim of this study was to investigate the effects of cuff deflation. ⋯ All patients were able to vocalise following cuff deflation. Twelve patients passed a blue dye swallow screen within a day of tolerating cuff deflation. These results suggest that pressures fall slightly following cuff deflation but this is associated with respiratory stability and may allow patients to talk and swallow.
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Randomized Controlled Trial Clinical Trial
Evaluation of a local anaesthesia regimen following mastectomy.
Breast surgery can be emotionally distressing and physically painful. Acute pain following surgery is often related mainly to the axillary surgery and is aggravated by arm and shoulder movement. We conducted a prospective double-blind, randomised, placebo-controlled trial to determine the influence of local anaesthetic irrigation of axillary wound drains on postoperative pain during the first 24 h following a modified Patey mastectomy (mastectomy with complete axillary node clearance). ⋯ Morphine consumption, visual analogue and verbal rating pain scores were recorded. There were no statistical differences in morphine requirements or pain scores between the two groups, nor were there differences in anti-emetic or supplemental analgesic consumption. Bupivacaine irrigation used in this manner does not appear to offer an effective contribution to postoperative analgesia.
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Multicenter Study
Propofol sedation using Diprifusor target-controlled infusion in adult intensive care unit patients.
This multicentre, non-comparative study investigated the range of target blood propofol concentrations required to sedate 122 adult intensive care patients when propofol was administered using Diprifusor target-controlled infusion systems together with opioid analgesia. Depth of sedation was assessed with a modified Ramsay score and the target blood propofol setting was adjusted to achieve the sedation desired for each patient. A desired level of sedation was achieved for 84% of the sedation period. ⋯ Values in brain injured and general ICU patients were 0.98 (10th - 90th percentiles: 0.60-2.55) microg.ml(-1) and 0.42 (10th - 90th percentiles: 0.16-1.19) microg.ml(-1), respectively. Measured propofol concentrations were generally close to values predicted by the Diprifusor system. Target settings in the range of 0.2-2.0 microg.ml(-1) are proposed for propofol sedation in this setting with titration as required in individual patients.