Anaesthesia
-
Randomized Controlled Trial Observational Study
The discriminatory value of cardiorespiratory interactions in distinguishing awake from anaesthetised states: a randomised observational study.
Depth of anaesthesia monitors usually analyse cerebral function with or without other physiological signals; non-invasive monitoring of the measured cardiorespiratory signals alone would offer a simple, practical alternative. We aimed to investigate whether such signals, analysed with novel, non-linear dynamic methods, would distinguish between the awake and anaesthetised states. We recorded ECG, respiration, skin temperature, pulse and skin conductivity before and during general anaesthesia in 27 subjects in good cardiovascular health, randomly allocated to receive propofol or sevoflurane. ⋯ The phase coherence was reduced by both agents at frequencies below 0.145 Hz (p < 0.05), whereas the cardiorespiratory synchronisation time was increased (p < 0.05). A classification analysis based on an optimal set of discriminatory parameters distinguished with 95% success between the awake and anaesthetised states. We suggest that these results can contribute to the design of new monitors of anaesthetic depth based on cardiovascular signals alone.
-
Randomized Controlled Trial
A randomised controlled trial of bilateral dual transversus abdominis plane blockade for laparoscopic appendicectomy.
We investigated the effects of pre-operative ultrasound-guided bilateral dual transversus abdominis plane blocks on pain when sitting up and pain at rest after laparoscopic appendicectomy. We allocated 28 participants to injection with 60 ml ropivacaine 0.375% and 28 participants to 60 ml isotonic saline. The median (IQR [range]) cumulative pain scores during the first 12 postoperative hours were less after ropivacaine than saline (maximum 120): on sitting, 34 (19-46 [0-59]) vs 50 (30-59 [0-97]), respectively, p = 0.009; and at rest, 25 (10-33 [0-49]) vs 31 (24-43 [0-72]), respectively, p = 0.035. There were no differences in morphine consumption, nausea, vomiting, time in recovery or time to walk.
-
Randomized Controlled Trial Comparative Study
A comparison of the i-gel(™) and the PRO-Breathe(®) laryngeal mask during pressure support ventilation in children.
Many studies comparing the i-gel(™) with laryngeal masks include patients in whom laryngeal mask cuff inflation pressures are higher than recommended, or involve the use of neuromuscular blocking drugs and positive pressure ventilation. We compared the i-gel with the PRO-Breathe(®) laryngeal mask in anaesthetised, spontaneously breathing children. Two hundred patients aged up to 16 years were randomly allocated to either the i-gel or the PRO-Breathe laryngeal mask. ⋯ Leakage volume was significantly higher with i-gel sizes 1.5 (p = 0.015), 2 (p = 0.375), 2.5 (p = 0.021) and 3 (p = 0.003) compared with the equivalent-sized PRO-Breathe device. Device dislodgement following successful initial placement was more frequent with the i-gel (5%) compared with the PRO-Breathe laryngeal mask (0%). We conclude that the PRO-Breathe laryngeal mask is superior to the i-gel in terms of leakage volume and device dislodgement.
-
Randomized Controlled Trial
The effect of a forced-air warming blanket on patients' end-tidal and transcutaneous carbon dioxide partial pressures during eye surgery under local anaesthesia: a single-blind, randomised controlled trial.
Surgical drapes used during eye surgery are impermeable to air and hence risk trapping air underneath them. We investigated the effect of a forced-air warming blanket on carbon dioxide accumulation under the drapes in patients undergoing eye surgery under local anaesthesia without sedation. Forty patients of ASA physical status 1 and 2 were randomly assigned to either the forced-air warmer (n = 20) or a control heated overblanket (n = 20). ⋯ We measured transcutaneous and end-tidal carbon dioxide partial pressures, heart rate, arterial pressure, respiratory rate, temperature and oxygen saturation before and after draping, then every 5 min thereafter for 30 min. The mean (SD) transcutaneous carbon dioxide partial pressure in the forced-air warming group stayed constant after draping at 5.7 (0.2) kPa but rose to a maximum of 6.4 (0.4) kPa in the heated overblanket group (p = 0.0001 for the difference at time points 15 min and later). We conclude that forced-air warming reduces carbon dioxide accumulation under the drapes in patients undergoing eye surgery under local anaesthesia.