Anaesthesia
-
Randomized Controlled Trial
The effect of gel lubrication on cuff leakage of double lumen tubes during thoracic surgery.
High-volume, low-pressure tracheal cuffs of disposable double lumen tubes may offer limited protection to the dependent lung if fluid leaks through folds in the inflated cuffs. This study was undertaken to determine the incidence of fluid leakage past the tracheal cuff and whether gel lubrication reduces the incidence. Fifty-five patients were randomly assigned to receive a double lumen tube with or without gel lubrication. ⋯ Three patients were excluded. Dye leakage was seen in 12/27 and 3/25 patients in the unlubricated and lubricated group, respectively (p = 0.014). Gel lubrication significantly reduces fluid leakage past the tracheal cuff of a double lumen tube and should be considered for all thoracic surgical patients requiring one-lung ventilation.
-
Randomized Controlled Trial
Minimum local anaesthetic dose (MLAD) of intrathecal levobupivacaine and ropivacaine for Caesarean section.
We determined the minimum local anaesthetic dose (MLAD) of spinal levobupivacaine and ropivacaine for Caesarean section. Ninety women were randomly allocated to two groups and received 3 ml of study solution by a combined spinal/epidural technique. The initial dose was 12 mg for levobupivacaine and 17 mg for ropivacaine groups. ⋯ Effective or ineffective responses determined, respectively, a 0.3 mg decrease or increase of the same drug for the next patient in the same group, using up-down sequential allocation. The MLAD of levobupivacaine was 10.58 mg (CI 95%: 10.08-11.09) and the MLAD of ropivacaine 14.22 mg (CI 95%: 13.67-14.77), using the Dixon and Massey formula. The potency ratio between spinal levobupivacaine and spinal ropivacaine was 1.34.
-
Randomized Controlled Trial Comparative Study
A comparison of the Soft Seal disposable and the Classic re-usable laryngeal mask airway.
Many new supraglottic airway devices have been recently introduced, their development motivated by the need for a single-use equivalent to the original re-usable laryngeal mask airway. We performed a randomised cross-over study in spontaneously breathing patients comparing the re-usable Laryngeal Mask Airway-Classic (LMA) and the disposable Soft Seal Laryngeal Mask in sizes 3, 4 and 5. Sixty patients had an LMA and a disposable laryngeal mask placed in random order. ⋯ The disposable laryngeal mask required significantly less air to inflate the cuff to produce a seal (10 [10-25] ml with disposable laryngeal mask and 15 [10-30] ml with laryngeal mask) and the cuff pressure produced was significantly lower (35 [20-80] cmH(2)O with disposable laryngeal mask and 75 [20-120] cmH(2)O with LMA). Data are median and range. We conclude that the disposable laryngeal mask is an acceptable alternative to the re-usable LMA.
-
Melodic alarms proposed in the IEC 60601-1-8 standard for medical electrical equipment were tested for learnability and discriminability. Thirty-three non-anaesthetist participants learned the alarms over two sessions of practice, with or without mnemonics suggested in the standard. Fewer than 30% of participants could identify the alarms with 100% accuracy at the end of practice. ⋯ Participants responded faster (p < 0.00001) and more accurately (p = 0.002) to medium priority alarms than to high priority alarms, even though they rated the high priority alarms as sounding more urgent (p < 0.00001). Participants with at least 1 year of formal musical training identified the alarms more accurately (p = 0.0002) than musically untrained participants, and found the task easier overall (p < 0.00001). More intensive studies of the IEC 60601-1-8 alarms are needed for their effectiveness to be determined.