British journal of anaesthesia
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The anaesthetic risks of acromegaly include difficulties in airway management, hypertension, and cardiac, gastrointestinal and renal problems. To estimate the incidence of major complications in this rare group of patients, we reviewed 28 patients with acromegaly who had pituitary tumour excision over a 10-yr period. Each patient was matched for age, weight and sex to a non-acromegalic patient undergoing transsphenoidal pituitary surgery. ⋯ Arterial pH was significantly lower (P = 0.015), blood glucose was higher (P < 0.001) and fluid intake minus output was higher (P = 0.04) in acromegalic patients than in controls. Airway difficulty and tongue enlargement were encountered more often in acromegalic patients (P = 0.002 and P = 0.001, respectively). Our data confirm that in acromegalic patients: airway difficulties occurred more frequently; severe haemodynamic instability did not typically occur during surgery for acromegaly; pulmonary gas exchange was not altered during operation; glucose intolerance may be an intraoperative problem; and fluid regulation may be altered.
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Comparative Study
Biologically variable ventilation prevents deterioration of gas exchange during prolonged anaesthesia.
We have studied the time course of changes in gas exchange and respiratory mechanics using two different modes of ventilation during 7 h of isoflurane anaesthesia in pigs. One group received conventional control mode ventilation (CV). The other group received biologically variable ventilation (BVV) which simulates the breath-to-breath variation in ventilatory frequency (f) that characterizes normal spontaneous ventilation. ⋯ The modulation file used to control the ventilator for BVV used an inverse power law frequency distribution (I/fa with a = 2.3 +/- 0.3). After 7 h, at a similar delivered minute ventilation, significantly greater PaO2 (mean 72.3 (SD 4.0) vs 63.5 (6.5) kPa) and respiratory system compliance (1.08 (0.08) vs 0.92 (0.16) ml cm H2O-1 kg-1) and lower PaCO2 (6.5 (0.7) vs 8.7 (1.5) kPa) and shunt fraction (7.2 (2.7)% vs 12.3 (6.2)%) were seen with BVV, with no significant difference in peak airway pressure (16.3 (1.2) vs 15.3 (3.7) cm H2O). A deterioration in gas exchange and respiratory mechanics was seen with conventional control mode ventilation but not with BVV in this experimental model of prolonged anaesthesia.
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Self-citation of a journal may affect its impact factor. We investigated self-citations in the 1995 and 1996 issues of six anaesthesia journals by calculating the self-citing and self-cited rates for each journal. Self-citing rate relates a journal's self-citations to its total number of references. ⋯ This also occurred, to a lesser extent, in the European anaesthesia journals. A significant correlation between self-citing rates and impact factors was found (r = 0.899, P = 0.015). A high self-citing rate of a journal may positively affect its impact factor.
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Tracheal intubation must be performed with great care in the multiply injured patient when it must be assumed that the cervical spine may be damaged. Use of conventional direct laryngoscopy usually requires removal of the neck collar and manual in-line stabilization of the head and neck. The intubating laryngeal mask (ILMA) has been designed to facilitate tracheal intubation in the neutral position. ⋯ In only two patients was intubation successful. These problems were probably caused by the neck collar strap under the chin lifting up and tipping the larynx anteriorly. On the basis of these findings, ILMA use in a subject wearing a neck collar cannot be recommended.