Anaesthesia and intensive care
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Anaesth Intensive Care · Jan 2010
Randomized Controlled TrialIncidence of residual neuromuscular blockade in a post-anaesthetic care unit.
We conducted a prospective observational study to assess the incidence of residual neuromuscular blockade (RNMB) in a post-anaesthetic care unit (PACU) of a tertiary hospital. The subjects were 102 patients undergoing general anaesthesia with neuromuscular blockade (NMB). The procedural anaesthetists were unaware of their patients' inclusion in the study, and the choice of muscle relaxant and use of reversal agents were at the anaesthetists' discretion. ⋯ Our findings suggest that RNMB in the PACU is common. As RNMB may predispose to postoperative complications, anaesthetists should utilise quantitative monitoring to assess neuromuscular blockade and optimise reversal use. Anaesthetists should be aware that intervals between the last dose of relaxant of well over one hour do not exclude the possibility of RNMB, even when using intermediate-acting neuromuscular blockade agents.
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Anaesth Intensive Care · Jan 2010
Clinical TrialEpisodic waveforms in the electroencephalogram during general anaesthesia: a study of patterns of response to noxious stimuli.
Previous studies of the electroencephalogram (EEG) during anaesthesia have identified two distinct patterns of change in response to a noxious stimulus, a classical arousal pattern and a paradoxical arousal pattern. We developed methods of EEG analysis to quantify episodic EEG patterns--namely sleep spindle-like ('10 Hz-score') and burst-suppression-like fluctuations in high frequencies ('high frequency variation index')--and used traditional power spectral quantification of non-episodic delta waves. We studied 30 healthy adult patients undergoing elective surgery under general anaesthesia with propofol, fentanyl (1.0, 2.5 or 4.0 microg/kg, n=10 for each group), muscle relaxant and sevoflurane. ⋯ The nociception-induced reduction in spindles was greater in the low-dose fentanyl group (P = 0.01). There was less tachycardia in the high-dose fentanyl group (P = 0.002). It is possible to quantify such episodic EEG patterns during general anaesthesia and in this study noxious stimulation tended to reduce the prevalence of these patterns.
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Anaesth Intensive Care · Jan 2010
Randomized Controlled TrialFentanyl dose for the insertion of Classic Laryngeal Mask Airways in non-paralysed patients induced with propofol 2.5 mg/kg.
The aim of this randomised, controlled trial was to determine the optimum dose of fentanyl in combination with propofol 2.5 mg x kg(-1) when inserting the Classic Laryngeal Mask Airway. Seventy-five ASA I or II patients were randomly assigned to five groups of fentanyl dosage: 0 microg x kg(-1) (placebo), 0.5 microg x kg(-1), 1.0 microg x kg(-1), 1.5 microg x kg(-1) and 2.0 microg x kg(-1). Anaesthesia was induced by first injecting the study drug over 10 seconds. ⋯ We found that there was a high rate of successful first attempt at insertion with 1 microg x kg(-1) and 1.5 microg x kg(-1), 93% and 87% respectively, compared to 87% in the 2.0 microg x kg(-1) group. The 1.0 microg x kg(-1) group also achieved an 80% optimal insertion conditions score of 4, compared to 73% in the 1.5 microg x kg(-1) group and 80% in the 2 microg x kg(-1) group. Therefore we recommend 1.0 microg x kg(-1) as the optimal dose of fentanyl when used in addition to propofol 2.5 mg/kg for the insertion of the Classic Laryngeal Mask Airway.
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Laryngeal mask airways (LMA) are commonly used in paediatric anaesthesia. A well-placed LMA should provide a direct view of the vocal cords facilitating bronchoscopy or fibreoptic intubation. The aim of this audit was to assess the bronchoscopic view of the glottis obtained through an LMA with regard to its size. ⋯ The epiglottis impinged on the LMA opening, partially obstructing the view of the glottis in 36.3% of size 1 LMAs, 31.5% of size 1.5, 21% of size 2 and 17.8% of size 2.5. In 13.7% of size 1 LMAs, 11% of size 1.5, 6.3% of size 2 and 4.4% of size 2.5, the epiglottis was completely downfolded, obstructing the view of the glottic aperture. The findings indicate that even if ventilation is judged as adequate, smaller paediatric LMAs are more commonly associated with suboptimal anatomical positioning with partial obstruction of the glottic aperture than larger LMAs, and therefore may require repositioning more often.
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Anaesth Intensive Care · Jan 2010
Comparative StudyIntubation through the LMA-Supreme: a pilot study of two techniques in a manikin.
The LMA-Supreme is a single-use disposable laryngeal mask that combines features of several laryngeal mask airways in one device. The primary aim of our study was to compare ease of use and operator preference for fibreoptic-aided intubation through the LMA-Supreme using an Aintree Intubating Catheter or Arndt Airway Exchange Catheter Set. Twenty participants experienced in fibreoptic-aided intubation performed a total of 40 intubations on an AirSim airway manikin through a #4 LMA-Supreme. ⋯ All 20 (100%) Arndt Airway Exchange Catheter Set-assisted intubations and 18/20 (90%) of Aintree Intubating Catheter-assisted intubations were successful. Aintree Intubating Catheter and Arndt Airway Exchange Catheter Set-assisted intubations can be performed quickly, successfully and with minimal difficulty through the LMA-Supreme by experienced operators. While the Arndt Airway Exchange Catheter may be easier the Aintree Intubating Catheter is faster.