Canadian journal of anaesthesia = Journal canadien d'anesthésie
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A 76-yr-old man underwent carinal resection for squamous cell carcinoma through the right posterolateral thoracotomy approach. Ventilation was maintained by the use of two high-frequency jet ventilators, each attached to a separate catheter during the time of resection and reconstruction of the tracheal carina. ⋯ During two-lung jet ventilation there was good oxygenation, normocapnia and no cardiovascular complications. The principle advantage of using two separate high-frequency ventilators is that it allows for maximum ventilatory efficiency with lungs of different compliance.
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Desflurane is a volatile anaesthetic that combines low blood gas solubility (blood/gas partition coefficient = 0.42 at 37 degrees C), moderate potency (MAC = 6-7%), and high volatility (vapour pressure = 681 mmHg at 20 degrees C, boiling point = 23.5 degrees C). The volatility and potency of desflurane prevent its safe use in vaporizers of traditional design. We present a mathematical model which demonstrates the potential for desflurane overdose if contemporary vaporizers are misfilled with desflurane. ⋯ The calculated desflurane output of a misfilled enflurane vaporizer at a dial setting of 1% and a temperature of 22 degrees C is 57.8%, or 9.6 MAC. For misfilled enflurane, isoflurane, and halothane vaporizers at dial settings equivalent to one MAC at 22 degrees C, the calculated desflurane output is 14.0, 10.2, and 7.8 MAC, respectively. We conclude that the safe delivery of desflurane will require engineering safeguards, additional monitoring, and education of the anesthesia community.
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Case Reports
Successful epidural anaesthesia for a patient with Takayasu's arteritis presenting for caesarean section.
The management of a 24-yr-old parturient with Takayasu's arteritis (TA) presenting at term for Caesarean section is discussed. The best anaesthetic management for the patient with TA is controversial, but avoiding regional anaesthesia has been suggested by some authors because of the risk of hypotension and the subsequent need for vasopressors. We report the use of regional anaesthesia in a term parturient with severe TA undergoing Caesarean section. ⋯ The initial doses of 60 mg and 150 mg were followed by a decrease in BP (from 110/70 to 70/40) which was corrected with iv fluids and ephedrine 25 mg. Additional doses of chloroprocaine, 150 and 90 mg, were uneventful. It is concluded that an epidural can be made in safety to provide anaesthesia for Caesarean section in patients with TA.
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We report a malignant hyperthermia-susceptible patient who required investigation for a large, symptomatic anterior mediastinal mass. Multiple attempts at tissue diagnosis under local anaesthesia were unsuccessful. ⋯ Diagnostic mediastinotomy was performed without incident. We conclude that ketamine anaesthesia is appropriate for patients with anterior mediastinal masses, and is considered safe in malignant hyperthermia-susceptible patients.