Anaesthesia
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Randomized Controlled Trial Comparative Study
A randomised, controlled trial comparing the Airtraq™ optical laryngoscope with conventional laryngoscopy in infants and children.
The Airtraq(™) optical laryngoscope became available in paediatric sizes in the UK in May 2008. We conducted a randomised, controlled trial comparing the Airtraq with conventional laryngoscopy during routine anaesthesia in children. We hypothesised that the Airtraq laryngoscope would perform as well as conventional laryngoscopy. ⋯ The mean (SD) intubation time using the Airtraq was longer than conventional laryngoscopy overall (47.3 (32.6) vs 26.3 (11.5) s; p=0.002), though the difference was only significant for children (p=0.003) and not for infants (p=0.29). The Airtraq provided a better view of the larynx compared with conventional laryngoscopy (in infants (percentage of glottic opening scores 100 (95-100 [90-100]) vs 77 (50-90 [40-100]), respectively; p=0.001; visual analogue scores for field of view 9.2 (9.2-9.5 [8.2-10.0]) vs 6.8 (5.1-8.0 [4.7-10.0]), respectively; p=0.001). In children, the Airtraq provided a similar view of the larynx (percentage of glottic opening scores 100 (100-100 [40-100]) vs 100 (90-100 [50-100]), respectively; visual analogue scores for field of view 9.2 (8.6-10.0 [7.0-10.0]) vs 9.2 (8.6-10.0 [5.6-10.0]), respectively; both p>0.05), compared with conventional laryngoscopy.
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Many anaesthetic agents affect intra-ocular pressure, yet little is known about nitrous oxide and intra-ocular pressure. This study assessed the effect of nitrous oxide on intra-ocular pressure in 20 healthy adult volunteers. The intra-ocular pressure was measured at baseline, while breathing a 70:30 mix of nitrous oxide and oxygen for 12 min, and then while breathing room air for 15 min. ⋯ There was no significant difference in intra-ocular pressure between baseline and during or after nitrous oxide inhalation. Several differences in intra-ocular pressure were noted between internal time-points: pressure increased by 2.4 mmHg between 3 and 6 min of breathing nitrous oxide (p=0.01); it increased by 1.4 mmHg between 3 and 9 min of breathing nitrous oxide (p=0.046); and it decreased by 2.2 mmHg between 6 min of breathing nitrous oxide and 15 min of breathing room air (p=0.035). This study indicates that nitrous oxide inhalation does not significantly change intra-ocular pressure from baseline values in a population of healthy adults.
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The aim of the present study was to determine the precision of the PiCCO(®) system for post-cardiac arrest patients who underwent therapeutic hypothermia. The precision of the measurements for cardiac output, global end-diastolic volume, extravascular lung water and the pulmonary vascular permeability index was assessed using the least significant change; this was regarded as precise when less than 15%. ⋯ No significant differences between hypothermia (n=150) and non-hypothermia (n=312) were found. The PiCCO-derived variables were found to be precise for post-cardiac arrest patients even under conditions of varying body temperature.
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Awake videolaryngoscopy may be useful for the tracheal intubation of the morbidly obese. This prospective, observational study enrolled 50 patients undergoing bariatric surgery. After sedation and topical anaesthesia of the airway, awake tracheal intubation was attempted, assisted by videolaryngoscopy, and terminated if there was severe gagging, coughing, or inadequate laryngeal view. ⋯ In one failure, inserting the tracheal tube caused severe gagging in spite of an adequate view of the larynx, and the trachea was intubated with the videolaryngoscope after induction of anaesthesia. The second failure was due to gagging, with subsequent tracheal intubation successful using fibreoptic bronchoscopy. When managing the morbidly obese airway, awake tracheal intubation using videolaryngoscopy may be considered.
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Forced-air warming exhaust may disrupt operating theatre airflows via formation of convection currents, which depends upon differences in exhaust and operating room air temperatures. We investigated whether the floor-to-ceiling temperatures around a draped manikin in a laminar-flow theatre differed when using three types of warming devices: a forced-air warming blanket (Bair Hugger™); an over-body conductive blanket (Hot Dog™); and an under-body resistive mattress (Inditherm™). ⋯ We conclude that forced-air warming generates convection current activity in the vicinity of the surgical site. The clinical concern is that these currents may disrupt ventilation airflows intended to clear airborne contaminants from the surgical site.