Research from G.W. Glover and co-researchers provides new data on anesthesia
2009 JUL 13 - (NewsRx.com) -- "There are few data describing the performance of the Whisperflow (R) continuous positive airway pressure (CPAP) generator. (i) (a) A static test of 11 Whisperflow devices examining maximum flow generation with no load and with 2.5, 5, 7.5, 10, 15, and 20 cm H2O valve loading, at varying Fi(o2). (b) CPAP valves (Accu-peep (R), Vital Signs, Totowa, NJ, USA) were tested by measuring mean upstream pressure at varying flows in five valves (2.5, 5, 7.5, 10, 15, and 20 cm H2O). (ii) We measured the mean and minimum inspiratory mask pressure generated by a representative Whisperflow device in a model of spontaneous respiration. were made with combinations of Fi(o2), ventilatory frequency, tidal volume, and valve loading similar to those encountered in clinical practice. (i) (a) The flow generated by the Whisperflow valves decreases with increasing valve load and increasing Fi(o2) (from 140 to 20 litre min(-1)). (b) The CPAP valves maintain the required pressure within acceptable limits against varying flow. (ii) At all permutations, the mean inspiratory mask pressure was significantly lower than that required," scientists writing in the British Journal of Anaesthesia report. "At high inspiratory flow rates, the minimum inspiratory pressure approached atmospheric pressure. The Whisperflow may not perform as expected. Clinicians should be cautious when using this device, particularly with high Fi(o2) and CPAP valve load. The flow setting should be set at maximum. Failure of CPAP therapy may be due to failure of the generator," wrote G.W. Glover and colleagues. The researchers concluded: "Further in vivo data are required.." Glover and colleagues published their study in British Journal of Anaesthesia (Assessing the performance of the Whisperflow(R) continuous positive airway pressure generator: a bench study. British Journal of Anaesthesia, 2009;102(6):875-881). Additional information can be obtained by contacting S.J. Fletcher, Bradford Teaching Hospital, NHS Foundation Trust, Intensive Care Unit, Duckworth Lane, Bradford BD9 6RJ, W Yorkshire, UK. The publisher of the British Journal of Anaesthesia can be contacted at: Oxford University Press, Great Clarendon St., Oxford OX2 6DP, England. Keywords: United Kingdom, Bradford, Life Sciences, Pain Medicine, Anesthesia. This article was prepared by Pain & Central Nervous System Week editors from staff and other reports. Copyright 2009, Pain & Central Nervous System Week via NewsRx.com.
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