British journal of anaesthesia
-
A major cause of impaired gas exchange during general anaesthesia is atelectasis, causing pulmonary shunt. A 'vital capacity' (VC) manoeuvre (i.e. inflation of the lungs up to 40 cm H2O, maintained for 15 s) may re-expand atelectasis and improve oxygenation. However, such a manoeuvre may cause adverse cardiovascular effects. ⋯ At an inspired oxygen concentration of 40%, PaO2 increased from 17.2 (4.0) kPa before to 22.2 (6.0) kPa (P = 0.013) after the VC manoeuvre. Thus in anaesthetized adults undergoing mechanical ventilation with healthy lungs, inflation of the lungs to a Paw of 40 cm H2O, maintained for 7-8 s only, may re-expand all previously collapsed lung tissue, as detected by lung computed tomography, and improve oxygenation. We conclude that the previously proposed time for a VC manoeuvre may be halved in such subjects.
-
Clinical Trial
Patient-controlled sedation using propofol in elderly patients in day-case cataract surgery.
Patient-controlled sedation (PCS) with propofol has been used successfully as an adjunct to local anaesthetic procedures. We studied a group of elderly patients (mean age 75.4 yr) undergoing cataract surgery and attempted to increase patient acceptability and comfort of local anaesthesia. Propofol was self-administered in a dose of 0.25 mg kg-1 for patients more than 60 yr of age, with a lockout period of 3 min. ⋯ However, while it is possible to administer PCS successfully to elderly patients undergoing cataract surgery and produce a decrease in the level of anxiety, we found it unacceptable because of head movement in two patients. These patients received only two and three divided doses, to a maximum of 29 and 30 mg, respectively. There were no other adverse events.
-
Editorial Comment
Rapacuronium (Org 9487): do we have a replacement for succinylcholine?