Anaesthesia
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Standard cardiorespiratory monitoring may fail to detect occult tissue ischaemia. This study assessed whether a near infra-red spectroscopy tissue oxygen saturation monitor (InSpectra™) could detect progressive peripheral tissue ischaemia and whether hyperoxia may confound tissue oxygen saturation measurement. ⋯ The rate and magnitude of decreases in tissue oxygen saturations were greater during high- than low-pressure ischaemia with a mean (SD) desaturation rate of 3.3 (0.9) vs 1.8 (0.8) %.min(-1) (p<0.01). The dose-related association and lack of confounding by hyperoxia suggest that tissue oxygen saturation monitoring may be a useful adjunct to detect occult ischaemia.
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Review Meta Analysis Comparative Study
A meta-analysis of the accuracy and precision of the ultrasonic cardiac output monitor (USCOM).
The ultrasonic cardiac output monitor is a non-invasive, continuous-wave Doppler monitor that can be used to measure cardiac output. Its accuracy and precision in peri-operative and critical care has been assessed with varied results. ⋯ The mean weighted bias was -0.39 l.min(-1) (95% CI -0.25 to -0.53 l.min(-1) ), precision 1.27 l.min(-1) and percentage error 42.7% (95% CI 38.5-46.9%). The ultrasonic cardiac output monitor achieved similar agreement with bolus thermodilution to that of other minimally invasive methods of peri-operative cardiac output monitoring, and may have a useful role in cardiac output monitoring.
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Hip fracture surgery is associated with a high rate of mortality and morbidity; heart disease is the leading cause and is often unrecognised and inadequately treated. Pre-operative focused transthoracic echocardiography by anaesthetists frequently influences management, but mortality outcome studies have not been performed to date. Mortality over the 12 months after hip fracture surgery, in 64 patients at risk of cardiac disease who received pre-operative echocardiography, was compared with 66 randomised historical controls who did not receive echocardiography. ⋯ Hazard of death was also reduced with pre-operative echocardiography over 12 months after adjustment for known risk factors (hazard ratio 0.41, 95% CI 0.2-0.85, p=0.016). Pre-operative echocardiography was not associated with a delay in surgery. These data support a randomised controlled trial to confirm these findings.
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Clinical Trial
The effect of a cervical collar on the seal pressure of the LMA Supreme™: a prospective, crossover trial.
For personnel inexperienced in airway management, supraglottic airway devices may be the first choice in an emergency. Changing head position is known to reduce the seal pressure of a laryngeal mask airway. The aim of this study was to investigate whether the use of a cervical collar improves the stability of airways secured with the LMA Supreme™ (The Laryngeal Mask Company Limited, Mahé, Seychelles). ⋯ With a cervical collar in place, the seal pressure increased to 28 (22.8-30 [17-30]) cmH(2) O (p<0.001). In the neutral head position, the seal pressure was 22 (17.6-24.5 [12-30]) cmH(2) O without and 27 (22-30 [12-30]) cmH(2) O with a cervical collar in place (p<0.001). We found that a cervical collar stabilises the airway with an LMA Supreme in place and we recommend this combination for (pre-hospital) emergency cases.